Part 2: Clean and safe
Stan Abbott, head of the Roof Water Harvesting Centre, at its windblown rooftop research station at Massey University’s Wellington campus. Photo: Rachel Rose
Typically, how clean is the rainwater being drunk in rural New Zealand? Often, not very. Stan Abbott heads up the Roof Water Harvesting Centre at Massey University. In 2006 Stan and his colleagues tested roof water samples from 560 homes for total coliforms (an indicator of environmental contamination e.g. soil and vegetation) and E. coli (an indicator of faecal contamination). Seventy percent of the sample failed the drinking water standard for New Zealand, which requires zero of either indicator in the mains supply. The study considered a level of 60 organisms per 100 ml to be ‘still contaminated but acceptable’, yet 53 percent of samples contained total coliforms in excess of this level and 30 percent had E. coli in excess of this somewhat arbitrary cut-off.
There’s something in the water
So what’s in the water? Faecal contamination sounds like … shit? Yes, it is: typically from birds, rodents and animals like possums that have defecated on the roof and gutters. But research shows animal and bird droppings can also be wind-blown from nearby trees. This brings the risk of E.coli, Salmonella, Campylobacter and others, all capable of making humans very sick.
Other sources of contamination include lead, leaves, soil and other organic debris, ash, chemicals, and the bodies of dead animals or insects in the gutters – or worst, in the tank itself.
Yet let’s remember humans have been collecting and drinking rainwater for thousands of years and vast numbers of the world’s current population still do. And the research also shows that people are not getting sick nearly as often as the data may lead us to expect.
Stan describes most rural rainwater systems as very rudimentary. “But a lot of people [drinking that water] will swear blind they never get sick – and I believe them,” he says.
The explanation for that is likely twofold, starting with under-reporting. “If people get sick, they’re more likely to think it’s food poisoning and blame last night’s takeaways,” Stan says. And unless a whole household gets very ill, the health authorities are unlikely to hear of it.
The other reason is human adaption: if people have been drinking the water for their whole life, they’ve built up immunity to the germs in their water supply.
Sean Lynch of Clearflow Contracting installs a lot of rainwater systems on large lifestyle blocks in the Manawatu and he’s often called in when townies move to the country onto a block with old tanks. “They’re used to town water, and they get sick on the tank water,” Sean observes. He sees far fewer issues with new tanks.
Getting clean
So how to make your tank water safe to drink? There is a bewildering array of accessories available and it’s hard to know where to start – and when to stop. Stan recommends these steps in this order.
1. Make sure your roof is a suitable material for collecting water. That means no lead paint, nails or flashings, no treated timber shingles, asphalt or tar roofing materials, and preferably not roofing materials containing asbestos. What’s suitable? Steel; concrete, clay or factory-painted tiles; slate; glass; PVC (without lead stabiliser added); fibreglass; polycarbonate; and untreated timber shingles.
2. Make sure the roof is clean and the gutters are clean and unblocked. Blocked gutters mean a lot of water will be spilled and won’t reach your tank. If gutters regularly clog or foul, Stan recommends installing gutter mesh. And be careful up that ladder when you’re clambering up onto the roof!
3. Install screened rain heads (ones with a single screen) on each downpipe. These are sold under various trade names but all work as a physical barrier that stops debris like leaves entering the pipes connected to your tank.
4. Consider a first-flush diverter. This is a chamber installed before the tank that collects the first amount of each rainfall, which in theory carries away any contamination that has built up on the roof since it last rained. Once the chamber is filled, a floating ball seals the chamber and subsequent water runs straight to the tank. The diversion chamber empties to the ground in a slow trickle via a nozzle. Small first-flush diverters can be wall-mounted or post-mounted beside the tank. You can make one yourself or buy a kit that fits onto a length of pipe, usually 90 mm or 300 mm for bigger systems. A diverter can also be fitted onto each downpipe. They can be buried, but this is officially recommended only on a sloping site where the contour allows the end of the chamber to be above ground (so the nozzle can be periodically removed and cleaned).
First-flush diverters
First-flush diverters introduce a lot of complexity into a rainwater harvesting system. You’ll collect less water – something to consider in drought-prone areas. It also makes for complex equations when estimating how much water you can capture, because you must consider not just total rainfall but the distribution of rain. How many rainfall events occur in a month or season? Remember, the larger the tank, the more diluted any incoming contaminants – many rural tanks are 15,000 litres or more.
There is another benefit to first-flush diverters: they can convert the typical ‘wet system’ to a dry system. In a wet system, there is always water in the pipes, to the height of the top of the tank. That water will become stagnant when days or weeks pass between rain falling, but it is pushed into the tank when it next rains. That fouled water would be sent to the first flush diverter if it is appropriately sized and properly sited within the system.
That’s a big if! First-flush diverters are not common; Sean has installed hundreds of tanks in the past five years, but only a handful of systems included a first-flush diverter and only because the client specified it. Stan’s met plumbers who didn’t even know what they were and the most common mistake he finds when consulting is incorrectly installed first-flush diverters (see case study on the Organic NZ website).
“Why is the message not getting through? Some tradespeople seem unwilling to read even the most basic technical information,” says Stan. He believes suppliers need to do more to educate the industry. Meanwhile, he suggests asking a lot of questions of prospective tradies: “How many rainwater tanks have you put in? How many first flush diverters? How often do you fit screened rain heads? Keep asking questions, and you’ll soon get a feel for what they know.”
It’s common to find sales material suggesting first flush diverters that hold a mere 15 or 20 litres of water. Stan advises 50 litres as a minimum. If you connect a first-flush diverter at the top of the vertical riser entering the tank, that won’t drain a wet system.
There are in-between solutions. Sean builds flushing points into the systems he installs, that can be uncapped on a rainy day to flush out physical debris. He typically installs two tanks on rural blocks. The tanks are level at the bottom; water collects into one tank and is drawn off the other. That makes for cleaner water because sediment settles at the bottom of the first tank and physical debris like leaves float on the top. Sean connects the tanks in series about 200–300 mm from the bottom via a fat connector (40–50 mm). That means the water level in each tank will always be equal, and water will move freely between the tanks even in heavy rain. Remember two tanks will always cost more than one large tank of equal capacity.
Filters and treatments
There is a whole other suite of filtering and water cleansing treatments that can be applied after the tank, before the water is pumped back into the house for consumption: coarse and fine filters, ultra-violet light, ozonation, charcoal under-bench filters … much is possible. Without doubt these all produce very clean water but professionals we spoke to aren’t convinced of the need and haven’t installed these systems in their own houses.
‘Going the whole hog’ gets expensive and requires ongoing maintenance. Sean has encountered clients who are willing to outlay the capital expense of sophisticated filtering but then baulk at the cost of replacing UV bulbs and physical filters. These might need replacing every year or removing and cleaning every few months.
Even a simple system requires maintenance. It’s a good idea to make a habit of regularly opening the access hatch. Is the water clear? Does it smell OK? These are basic and reliable indicators of water quality. Make sure the hatch is always secured. The writer has lived in remote communities reliant on rainwater where dead possums fouled large tanks for weeks before detection. More tragic are some cases in Australia of children drowning in water tanks left unsecured.
Cleaning and maintenance
Gutters should be checked and cleared when necessary. Stan emphasises designing the rainwater harvesting system so the tank can be easily and swiftly disconnected from the pipes. This is crucial in an emergency: the last time there was a volcanic eruption on the Central Plateau and ash was falling from the sky, some people had to cut their downpipes to isolate their tanks. It’s also necessary if you need to wash down your roof. Tip: don’t glue in your screened rainheads. They may need securing; do this with a single screw. When necessary, remove them and block the open downpipe. A tennis ball does an adequate job in 90 mm pipes! Otherwise, design fittings at the tank that can be disconnected but consider where the water will discharge.
Some authorities are saying tanks must be drained and cleaned every year but Stan considers this unnecessary and expensive. “Rather, concentrate on preventing stuff from getting into the tank in the first place. Draining and cleaning is only called for if someone has got very sick or you have ongoing problems.”
Most councils require backflow prevention devices to be fitted when tank water is plumbed into the house. That will likely require a building consent: always check with your local and regional authority because regulations vary considerably throughout the country. All plumbing work must be carried out by a qualified plumber.
Beware spraydrift
One final and important warning for rural areas: beware spraydrift of agrichemicals. There’s a code of practice that should be followed but there are still real risks of roof contamination. See Appendix 3 in this document for guidelines:http://bit.ly/1tbbBHl.
Rachel Rose is establishing an urban permaculture property in Whanganui.
Rainwater butts revisited
In Part I, we looked at small rainwater butts that provide some emergency drinking water supply in urban areas. The open wooden barrel that illustrated the story looks beautiful, in a rustic, traditional way, but an open container of water is an invitation to massive contamination from bird and animal droppings (and dead animals and insects: rotting possum, anyone?) and the sunlight will produce algae. You’ll also create a mozzie breeding paradise, right next to your house.
Do consider the plastic butts – with lids! – of which many types are available.
You can also recycle a food-grade plastic barrel with a tight fitting lid: ensure it was only ever used to transport food, not chemicals.
Remember you must treat this water if you have to drink it in an emergency. Boil it; or use additives like Acquasafe or Pour N Go, which are preferable to chlorine bleach. They break down without residuals.
A cautionary tale
Poor design and installation is costly and inefficient. Consider this litany of problems that arose in a recent installation of a small suburban rainwater harvesting system. Its primary function was to buffer the release of stormwater into a block that is waterlogged in winter. Physical and geological constraints required siting a small (5400-litre) tank close to the house. Plumbing into the laundry etc. was ruled out, after a $10K quote.
The system was put in by an experienced drainlayer who claimed to have installed lots of rainwater tanks. Turns out he had done a few: basic systems on farms, with no additional fittings. Screened rainheads were new to him and he was flummoxed by the first-flush diverter. The homeowner knew how she wanted the system to function and specified the components but did not supervise the work closely, relying on the tradie’s supposed expertise. Mistake #1: Tradesperson’s expertise not established, references not checked.
The homeowner wanted to use the water on the garden and as an emergency drinking supply, so was concerned about water quality. Mistake #2: the roof wasn’t inspected or cleaned prior to plumbing into the tank. Screened rainheads were cut into the four downpipes. Three are easily accessible; the fourth is cut in 3.3 m above ground (mistake #3), requiring an extension ladder and assistance to remove the screen and clean it. Result: six months later, it hasn’t been cleaned. (One plus: the rainheads were not glued into the pipes.)
It was with the first-flush diverter that things really went awry. The supplier calculated that about 230 litres of water needed to be diverted given the size of the roof and the relatively small tank. That required a three-metre length of 300 mm pipe that needed to run underground: not cheap, and a lot of digging too. Fittings were bodged to save costs and the bottom of the system was sealed with a rubber gasket fitted to a trickle-fed nozzle that discharged the diversion chamber. The diversion chamber was at the bottom of the whole system, about 1.2 metres lower than the bottom of the tank. The wrong components were installed and the ball didn’t block the diversion chamber once it was full. The water pressure from heavy rain blew the rubber gasket clear off the pipe: water gushed out and nothing reached the tank. How to count the mistakes here? (#4) Well-meaning and helpful suppliers lacked experience with first-flush diverters and (#5) the tradesperson was completely out of his depth. And out of patience too, which made for a tense environment.
Site visits ensued from the local agent and the supplier – and by Massey University’s Stan Abbott, with two French PhD students in tow. Upshot? The problems outlined above were identified. The first-flush diverter was dug up and the fittings scrapped. A Marley first-flush diverter kit was fitted to the 300 mm pipe, a new ditch dug, the correct components installed and buried at the exact 12 degree angle specified by Stan … and breath was held until the next rain, at which point the system operated correctly.
But it wasn’t entirely over. Months later, problems emerged with the positioning of the tank. The drainlayer didn’t use fittings to connect the inlet and outlet pipes into the tank (#6); rather he’d made a rough hole with a jigsaw (rather than a hole saw)(#7), and used a cheap silicone substitute to patch around the holes (#8). Exposed to UV, this compound quickly broke down and the tank started leaking around the inlet pipe. These pipes should have been plumbed in beside the access hatch. Instead they were on the opposite side of the tank (#9) – so in order to repair the pipe fittings, someone had to climb into the tank, two-thirds full of water. That someone was the slender homeowner, because the plumber called in to fix up the shoddy work was too burly to fit through the hatch!
The joy in crop swapping
/in Features, Magazine ArticlesFranziska von Hünerbein writes about a movement that’s about sharing excess produce, community connection, and so much more.
We hope you enjoy this free article from OrganicNZ. Join us for access to exclusive members-only content.
It all began with a tree, a big lemon tree full of bright juicy fruit. There it was, radiating beauty and offering abundance – unfortunately not to us, as it was growing in a neighbour’s garden down the road. I admired it from afar and was longing for lemons to cook my rhubarb jam with.
One day I gathered all my courage, knocked on my neighbour’s door and asked politely whether they were planning to eat these hundreds of lemons by themselves or whether they would be happy to give us a few. He quickly got a box, filled it with fruits and swapped it for a jar of rhubarb jam.
I have been a hedge peeker, a garden sneaker, a fruit stealer all my life. Spotting a tree full of fruits fills me with joy; seeing fruits rotting on the ground highly irritates me and brings up questions. When researching online I came across green swaps, vege swaps, food swaps and crop swaps all over the world. Names, logos and formats vary; the concept is the same. People meet, bring what they have, and exchange it for what they need. After a good read I knew we would do this!
Let me take you to a Crop Swap Taranaki gathering. People carry full boxes and baskets into the community hall, sign in, find a free table and proudly display their goods. Neighbours and friends greet each other, walk around, admire produce, exchange gardening tips and welcome newcomers. Children run around, eye cupcakes and pet the ducklings. The whole room is buzzing with excitement and anticipation. The variety on offer is huge: vegetables, fruits, plants, flowers, seedlings, herbs, eggs, preserves, jams, baking, liquid manure, gardening books, magazines, planting containers, sometimes even chooks who need a new home. After half an hour of admiration and connection time, the swap is opened with a brief introduction and everyone is welcome to take a fair share of what they are interested in. Everything is free. Baskets fill, tables clear and after a quick clean-up everyone leaves with fresh local produce and a big smile.
Where does this immense joy come from, that floods everyone who enters the Crop Swap temple? Is it really just about swapping local produce to fill our stomachs? Crop Swap gatherings seem to meet many profound human needs. Connection is a biggie. For some people it is the social highlight of their week. They meet neighbours and friends, learn from the elders, hold a baby, are seen, are greeted, are hugged.
We all have a need to be of service, to give and be recognised for that. The joy of generosity shows in the immense effort that some put into preparation and presentation: jars are labelled, fruits polished, muffins beautifully decorated, bunches of flowers bring colour to the tables.
Most Crop Swappers are keen gardeners. Having our hands in the soil, witnessing growth, experiencing the seasons, observing and caring for all the expressions of life around us gives us peace and a sense of belonging. Sharing the fruits of this work with others is the cherry on top.
Crop Swap gatherings have potential beyond the generous sharing of food. So far we have had mini workshops on seed sowing, organic gardening, sourdough bread making, food fermentation and the benefits of raw milk. Crop Swap Taranaki is connected to the food bank, the seed bank, the time bank, the environment centre Hive, and to our future community café. Imagine the possibilities of cooperation!
Since the first Crop Swap gathering in New Plymouth our movement is constantly growing. We have three venues around Mount Taranaki (see box below), and there are more to come. Ideally we will have a Crop Swap Hub in every suburb and village of New Zealand, or, let’s say, the world. Creating one is easy. All you need is a venue and the people. In Taranaki we use a community hall, a church hall and a café as venues. Costs are covered by gold coin donations. We communicate via our local newspaper, school newsletters, email lists and our Facebook page.
On Saturday 5 September we celebrated Crop Swap Taranaki’s 2nd birthday. And while we shared a huge birthday cake, we also celebrated being part of a paradigm shift, where giving with a mindset of abundance and taking with a mindset of fairness will lead into a future of collective wellbeing.
Thank goodness it’s lemon season again.
Note from the Organic NZ office: as this article was published in 2015, some of the below information may be outdated. Use their Facebook page or get in touch with Franziska for current times.
Taranaki venues
More information
Franziska von Hunerbein, 06 769 6841, franziska@babuli.eu
Facebook: Crop Swap Taranaki
Franziska von Hünerbein lives with her family, a cat, chooks and a beehive in suburban New Plymouth, and is passionate about creating an abundant local food production in and for her community.
Why ban glyphosate?
/in Farming and Horticulture, Magazine ArticlesWe hope you enjoy this free article from OrganicNZ. Join us for access to exclusive members-only content.
Glyphosate is the active ingredient in Monsanto’s herbicide Roundup, and other proprietary brands by Bayer, Dow, Zeneca, Nufarm and others.
It is the most used herbicide worldwide in agriculture, horticulture, viticulture, forestry, industrial and public sites, aquatic environments, gardens, sports and school grounds. A US patent even covers in vivo use for animals or humans as an antibiotic treatment of pathogenic infections.
Such widespread use provides uncountable exposure pathways, and concerns about the effects of glyphosate are increasingly raised.
More than the ‘active’ ingredient
In tests of active and added ingredients in nine pesticides, glyphosate was found the most toxic, challenging ‘the relevance of the acceptable daily intake for pesticides because this norm is calculated from the toxicity of the active principle alone’.[1]
Glyphosate is not included in compounds tested by the US FDA’s Pesticide Residue Monitoring Program or the USDA’s Pesticide Data Program and, in assessing safety, the cumulative effects of approved levels on the human or physical environment are not taken into account.
Environmental effects
Glyphosate-resistant and other transgenes have transferred to weeds and non-transgenic crops. Glyphosate-resistant weeds exist in 18 countries, with significant impacts in the USA, Brazil, Australia, Argentina and Paraguay. In the American South, 86% of corn, soy and cotton farmers are affected by herbicide-resistant weeds. Resistance has been identified in some New Zealand locations, attributed to ‘over application’ of the herbicide.[2]
Glyphosate is a chelator of minerals; it combines with other minerals to make them available only under certain conditions. In plants, root uptake and shoot translocation of manganese and iron are severely depressed by glyphosate applications.[3],[4]Copper adsorption decreases in general with increasing concentration of glyphosate in solution.[5]Glyphosate also reduces seed and leaf concentrations of calcium, manganese, magnesium, and iron in non-glyphosate-resistant soybeans,[6]decreases in seed concentration being specific and potentially affecting seed quality.[7]
Glyphosate’s median half-life in soil is between two and 197 days, depending on soil and climate conditions, and can reach 1699 days under anaerobic conditions. Its median half-life can reach 91 days in water.[8] It adsorbs to suspended soil particles, and is not readily broken down by water or sunlight in surface water.[9],[10]
Denmark has banned autumn spraying of glyphosate where it contaminates groundwater to five times over the allowed limit and where it is a source of drinking water.[11]
Pesticide Action Network Asia Pacific says of greatest concern are the effects ‘that occur at a subtle level, and can result in significant disruption of aquatic and terrestrial eco-systems, including the agro-ecosystem’.[12]
Human health effects
An estimated 90% of transgenic crops grown globally are engineered to be glyphosate-resistant. In 2012, they accounted for45.2% of the total glyphosate demand. Glyphosate-resistant canola/rapeseed, corn/maize, cottonseed, soybeans and sugar beet provide common ingredients in a huge range of food products. Transgenic soy alone represents 77% of global soy production.
The only known peer-reviewed study on human volunteers ingesting transgenic DNA revealed detectable levels in the gut bacteria of participants.[13]For two decades, US citizens in particular have ingested multiple unlabelled transgenes every day. Medical professionals in the US point to this fact to help explain the huge rise in chronic diseases since the release of commercial transgenic crops.
Evidence is mounting that glyphosate interferes with many metabolic processes in plants and animals, and glyphosate residues have been detected in both. Correlation analyses of official statistics revealed strong significance of the effects of glyphosate and transgenic crops on human health.[14]
Negative impacts of transgene ingestion can manifest slowly over time by damaging cellular systems, including oxidative stress, endocrine disruption as general mechanisms of harm that result in insidious effects. A 2002 paper on the effect on cell cycle regulation of glyphosate-containing Roundup concluded: ‘results question the safety of glyphosate and Roundup on human health’.[15]
A 2009 study concluded that glyphosate-based herbicides ‘present DNA damages and CMR [carcinogenic/mutagenic/reprotoxic] effects on human cells and in vivo.[16]Even at very low doses, exposure to glyphosate-based herbicides may result in reproductive and hormonal problems, miscarriages, low birth weights, pre-term deliveries, and birth defects.
Accumulating through the food chain
Urine samples taken from 182 participants in 18 European countries revealed glyphosate in 43.9% of the samples.[17]Breast milk samples given by lactating mothers revealed glyphosate levels of 76–166 micrograms per litre (µg/l), which is 760–1600 times higher than the European Drinking Water Directive allows for individual pesticides, but less than the 700 µg/l maximum contaminant level allowed by the US EPA based on the premise that glyphosate is not bioaccumulative.[18]
Animal feed imported into New Zealand frequently contains ingredients from glyphosate-resistant crops, resulting in the bioaccumulation of glyphosate and/or glyphosate metabolites in feeding animals, adding to the human end-user intake.
All animals, including humans, bioaccumulate nutrients, and can bioaccumulate substances in the body to levels that can cause harm. A typical food chain bioaccumulation process is plant uptake from soil or spray, animal eating plant, human eating animal. Each step can result in increased bioaccumulation including toxins where absorption of a substance is at a rate greater than that at which the substance is lost or eliminated. One study concluded that animals and humans eating transgenic soy ‘chronically incorporate unknown amounts of this herbicide’.[19]
Novel proteins, increased allergens
Introducing novel DNA into a plant’s genome can result in the production of proteins new to the human diet, and increasing levels of existing, known allergenic proteins, e.g. lectins and trypsin inhibitors in transgenic soy. The more transgenic plants are present in the food chain, the more potential for consuming proteins new to a diet.
Allergic reactions to these proteins may not reveal themselves immediately. Many symptoms identified in a study into allergic reactions to glyphosate-resistant soy may be related to glyphosate exposure, e.g. irritable bowel syndrome, digestion problems, chronic fatigue, headaches, lethargy, and skin complaints.[20]
Why we need a ban
Two decades after the introduction of genetically engineered crops, there remains no official monitoring of the consequences to the human population ingesting resistant transgenes and/or glyphosate-based herbicides (which are used on 80% of the GE crops worldwide), and consumers have no official notification of risks.
From pre-emergence to pre-harvest, glyphosate is applied to food crops. Almost every non-organic processed food item in the supermarket or on a menu is likely to be contaminated by glyphosate in some way.
Authorities need to apply the precautionary principle and ban the use of glyphosate.
Doctors and scientists say: ban glyphosate
Read why Physicians and Scientists for Global Responsibility are calling for a ban on glyphosate:www.psgr.org.nz/glyphosate-calling-for-a-ban/finish/8-uncategorised/25-glyphosate-calling-for-a-ban
REFERENCES
[1]Mesnages, R et al. 2014. Major pesticides are more toxic to human cells than their declared active principles. BioMed Research International. www.hindawi.com/journals/bmri/aip/179691
[2]www.far.org.nz/index.php/media/entry/glyphosate-resistance-confirmed-in-new-zealand
[3]Eker, S. 2008. Foliar-applied glyphosate substantially reduced uptake and transport of iron and manganese in sunflower (Helianthus annuus L.) plants. J Agric Food Chem. 54(26).www.ncbi.nlm.nih.gov/pubmed/17177536. Tesfamariam, T et al. 2009. Glyphosate in the rhizosphere: Role of waiting times and different glyphosate binding forms in soils for phytotoxicity to non-target plants. European Journal of Agronomy, 31.
wyofile.com/wp-content/uploads/2011/07/2009_Glyphosate_Rhizosphere_Waitingtimes_Bindingformsinsoils_Tesfamariamaetal.pdf
[4]www.ncbi.nlm.nih.gov/pubmed/24562182
[5]Jayasumana, C et al. 2014. Glyphosate, hard water and nephrotoxic metals: are they the culprits behind the epidemic of chronic kidney disease of unknown etiology in Sri Lanka? Int J Environ Res Public Health.www.sciencedirect.com/science/article/pii/S0045653501003381.
[6]Cakmak, I et al. 2009.Glyphosate reduced seed and leaf concentrations of calcium, manganese, magnesium, and iron in non-glyphosate resistant soybean. European J Agronomy. 31(3).www.sciencedirect.com/science/article/pii/S1161030109000665
[7]research.sabanciuniv.edu/13147/1/2009_Glyphosate_reduced_seed_and_leaf_concentrations_of_calcium_etc.pdf
[8]npic.orst.edu/factsheets/glyphotech.html
[9]maps.thefullwiki.org/Glyphosate
[10]“Registration Decision Fact Sheet for Glyphosate (EPA-738-F-93-011)” 1993.
[11]Politiken. organic.com.au/news/2003.09.15
[12]Watts MA. 2009. Glyphosate Monograph. Pesticide Action Network Asia and the Pacific, Penang.www.panap.net/sites/default/files/monograph_glyphosate.pdf,
[13]Trudy Netherwood et al. 2004. Assessing the survival of transgenic plant DNA in the human gastrointestinal tract.Nature Biotechnology22. www.nature.com/nbt/journal/v22/n2/full/nbt934.html
[14]Swanson, Net al. 2014. Genetically engineered crops, glyphosate and the deterioration of health in the United States of America. Journal of Organic Systems, 9(2), 2014. www.organic-systems.org/journal/92/JOS_Volume-9_Number-2_Nov_2014-Swanson-et-al.pdf
[15]Marc J et al. 2002. Pesticide Roundup provokes cell division dysfunction at the level of CDK1/cyclin B activation.
Chem Res Toxicol. 15(3). www.ncbi.nlm.nih.gov/pubmed/11896679.
[16]Gasnier, C et al. 2009. Glyphosate-based herbicides are toxic and endocrine disruptors in human cell lines. Toxicology 262.
www.gmoseralini.org/wp-content/uploads/2013/01/Gasnieral.TOX_2009.pdf
[17]www.foeeurope.org/sites/default/files/glyphosate_studyresults_june12.pdf
[18]www.momsacrossamerica.com/glyphosate_testing_results
[19]Kruger, M et al. 2014. Detection of glyphosate residues in animals and humans. Journal of Environmental and Analytical Toxicology 4:210.dx.doi.org/10.4172/2161-0525.1000210
[20]Jeffrey Smith. 2007.Genetically engineered foods may cause rising food allergies: Genetically engineered soybeans. institute for responsible technology. www.responsibletechnology.org/gmo-dangers/health-risks/articles-about-risks-by-jeffrey-smith/Genetically-Engineered-Foods-May-Cause-Rising-Food-Allergies-Genetically-Engineered-Soybeans-May-2007
Illustration: Duncan Hill, http://hilldogg-visionary.blogspot.com
Rainwater harvesting, part 2: Clean and safe
/in Building and Technology, Magazine ArticlesPart 2: Clean and safe
Stan Abbott, head of the Roof Water Harvesting Centre, at its windblown rooftop research station at Massey University’s Wellington campus. Photo: Rachel Rose
Typically, how clean is the rainwater being drunk in rural New Zealand? Often, not very. Stan Abbott heads up the Roof Water Harvesting Centre at Massey University. In 2006 Stan and his colleagues tested roof water samples from 560 homes for total coliforms (an indicator of environmental contamination e.g. soil and vegetation) and E. coli (an indicator of faecal contamination). Seventy percent of the sample failed the drinking water standard for New Zealand, which requires zero of either indicator in the mains supply. The study considered a level of 60 organisms per 100 ml to be ‘still contaminated but acceptable’, yet 53 percent of samples contained total coliforms in excess of this level and 30 percent had E. coli in excess of this somewhat arbitrary cut-off.
There’s something in the water
So what’s in the water? Faecal contamination sounds like … shit? Yes, it is: typically from birds, rodents and animals like possums that have defecated on the roof and gutters. But research shows animal and bird droppings can also be wind-blown from nearby trees. This brings the risk of E.coli, Salmonella, Campylobacter and others, all capable of making humans very sick.
Other sources of contamination include lead, leaves, soil and other organic debris, ash, chemicals, and the bodies of dead animals or insects in the gutters – or worst, in the tank itself.
Yet let’s remember humans have been collecting and drinking rainwater for thousands of years and vast numbers of the world’s current population still do. And the research also shows that people are not getting sick nearly as often as the data may lead us to expect.
Stan describes most rural rainwater systems as very rudimentary. “But a lot of people [drinking that water] will swear blind they never get sick – and I believe them,” he says.
The explanation for that is likely twofold, starting with under-reporting. “If people get sick, they’re more likely to think it’s food poisoning and blame last night’s takeaways,” Stan says. And unless a whole household gets very ill, the health authorities are unlikely to hear of it.
The other reason is human adaption: if people have been drinking the water for their whole life, they’ve built up immunity to the germs in their water supply.
Sean Lynch of Clearflow Contracting installs a lot of rainwater systems on large lifestyle blocks in the Manawatu and he’s often called in when townies move to the country onto a block with old tanks. “They’re used to town water, and they get sick on the tank water,” Sean observes. He sees far fewer issues with new tanks.
Getting clean
So how to make your tank water safe to drink? There is a bewildering array of accessories available and it’s hard to know where to start – and when to stop. Stan recommends these steps in this order.
1. Make sure your roof is a suitable material for collecting water. That means no lead paint, nails or flashings, no treated timber shingles, asphalt or tar roofing materials, and preferably not roofing materials containing asbestos. What’s suitable? Steel; concrete, clay or factory-painted tiles; slate; glass; PVC (without lead stabiliser added); fibreglass; polycarbonate; and untreated timber shingles.
2. Make sure the roof is clean and the gutters are clean and unblocked. Blocked gutters mean a lot of water will be spilled and won’t reach your tank. If gutters regularly clog or foul, Stan recommends installing gutter mesh. And be careful up that ladder when you’re clambering up onto the roof!
3. Install screened rain heads (ones with a single screen) on each downpipe. These are sold under various trade names but all work as a physical barrier that stops debris like leaves entering the pipes connected to your tank.
4. Consider a first-flush diverter. This is a chamber installed before the tank that collects the first amount of each rainfall, which in theory carries away any contamination that has built up on the roof since it last rained. Once the chamber is filled, a floating ball seals the chamber and subsequent water runs straight to the tank. The diversion chamber empties to the ground in a slow trickle via a nozzle. Small first-flush diverters can be wall-mounted or post-mounted beside the tank. You can make one yourself or buy a kit that fits onto a length of pipe, usually 90 mm or 300 mm for bigger systems. A diverter can also be fitted onto each downpipe. They can be buried, but this is officially recommended only on a sloping site where the contour allows the end of the chamber to be above ground (so the nozzle can be periodically removed and cleaned).
First-flush diverters
First-flush diverters introduce a lot of complexity into a rainwater harvesting system. You’ll collect less water – something to consider in drought-prone areas. It also makes for complex equations when estimating how much water you can capture, because you must consider not just total rainfall but the distribution of rain. How many rainfall events occur in a month or season? Remember, the larger the tank, the more diluted any incoming contaminants – many rural tanks are 15,000 litres or more.
There is another benefit to first-flush diverters: they can convert the typical ‘wet system’ to a dry system. In a wet system, there is always water in the pipes, to the height of the top of the tank. That water will become stagnant when days or weeks pass between rain falling, but it is pushed into the tank when it next rains. That fouled water would be sent to the first flush diverter if it is appropriately sized and properly sited within the system.
That’s a big if! First-flush diverters are not common; Sean has installed hundreds of tanks in the past five years, but only a handful of systems included a first-flush diverter and only because the client specified it. Stan’s met plumbers who didn’t even know what they were and the most common mistake he finds when consulting is incorrectly installed first-flush diverters (see case study on the Organic NZ website).
“Why is the message not getting through? Some tradespeople seem unwilling to read even the most basic technical information,” says Stan. He believes suppliers need to do more to educate the industry. Meanwhile, he suggests asking a lot of questions of prospective tradies: “How many rainwater tanks have you put in? How many first flush diverters? How often do you fit screened rain heads? Keep asking questions, and you’ll soon get a feel for what they know.”
It’s common to find sales material suggesting first flush diverters that hold a mere 15 or 20 litres of water. Stan advises 50 litres as a minimum. If you connect a first-flush diverter at the top of the vertical riser entering the tank, that won’t drain a wet system.
There are in-between solutions. Sean builds flushing points into the systems he installs, that can be uncapped on a rainy day to flush out physical debris. He typically installs two tanks on rural blocks. The tanks are level at the bottom; water collects into one tank and is drawn off the other. That makes for cleaner water because sediment settles at the bottom of the first tank and physical debris like leaves float on the top. Sean connects the tanks in series about 200–300 mm from the bottom via a fat connector (40–50 mm). That means the water level in each tank will always be equal, and water will move freely between the tanks even in heavy rain. Remember two tanks will always cost more than one large tank of equal capacity.
Filters and treatments
There is a whole other suite of filtering and water cleansing treatments that can be applied after the tank, before the water is pumped back into the house for consumption: coarse and fine filters, ultra-violet light, ozonation, charcoal under-bench filters … much is possible. Without doubt these all produce very clean water but professionals we spoke to aren’t convinced of the need and haven’t installed these systems in their own houses.
‘Going the whole hog’ gets expensive and requires ongoing maintenance. Sean has encountered clients who are willing to outlay the capital expense of sophisticated filtering but then baulk at the cost of replacing UV bulbs and physical filters. These might need replacing every year or removing and cleaning every few months.
Even a simple system requires maintenance. It’s a good idea to make a habit of regularly opening the access hatch. Is the water clear? Does it smell OK? These are basic and reliable indicators of water quality. Make sure the hatch is always secured. The writer has lived in remote communities reliant on rainwater where dead possums fouled large tanks for weeks before detection. More tragic are some cases in Australia of children drowning in water tanks left unsecured.
Cleaning and maintenance
Gutters should be checked and cleared when necessary. Stan emphasises designing the rainwater harvesting system so the tank can be easily and swiftly disconnected from the pipes. This is crucial in an emergency: the last time there was a volcanic eruption on the Central Plateau and ash was falling from the sky, some people had to cut their downpipes to isolate their tanks. It’s also necessary if you need to wash down your roof. Tip: don’t glue in your screened rainheads. They may need securing; do this with a single screw. When necessary, remove them and block the open downpipe. A tennis ball does an adequate job in 90 mm pipes! Otherwise, design fittings at the tank that can be disconnected but consider where the water will discharge.
Some authorities are saying tanks must be drained and cleaned every year but Stan considers this unnecessary and expensive. “Rather, concentrate on preventing stuff from getting into the tank in the first place. Draining and cleaning is only called for if someone has got very sick or you have ongoing problems.”
Most councils require backflow prevention devices to be fitted when tank water is plumbed into the house. That will likely require a building consent: always check with your local and regional authority because regulations vary considerably throughout the country. All plumbing work must be carried out by a qualified plumber.
Beware spraydrift
One final and important warning for rural areas: beware spraydrift of agrichemicals. There’s a code of practice that should be followed but there are still real risks of roof contamination. See Appendix 3 in this document for guidelines:http://bit.ly/1tbbBHl.
Rachel Rose is establishing an urban permaculture property in Whanganui.
Rainwater butts revisited
In Part I, we looked at small rainwater butts that provide some emergency drinking water supply in urban areas. The open wooden barrel that illustrated the story looks beautiful, in a rustic, traditional way, but an open container of water is an invitation to massive contamination from bird and animal droppings (and dead animals and insects: rotting possum, anyone?) and the sunlight will produce algae. You’ll also create a mozzie breeding paradise, right next to your house.
Do consider the plastic butts – with lids! – of which many types are available.
You can also recycle a food-grade plastic barrel with a tight fitting lid: ensure it was only ever used to transport food, not chemicals.
Remember you must treat this water if you have to drink it in an emergency. Boil it; or use additives like Acquasafe or Pour N Go, which are preferable to chlorine bleach. They break down without residuals.
A cautionary tale
Poor design and installation is costly and inefficient. Consider this litany of problems that arose in a recent installation of a small suburban rainwater harvesting system. Its primary function was to buffer the release of stormwater into a block that is waterlogged in winter. Physical and geological constraints required siting a small (5400-litre) tank close to the house. Plumbing into the laundry etc. was ruled out, after a $10K quote.
The system was put in by an experienced drainlayer who claimed to have installed lots of rainwater tanks. Turns out he had done a few: basic systems on farms, with no additional fittings. Screened rainheads were new to him and he was flummoxed by the first-flush diverter. The homeowner knew how she wanted the system to function and specified the components but did not supervise the work closely, relying on the tradie’s supposed expertise. Mistake #1: Tradesperson’s expertise not established, references not checked.
The homeowner wanted to use the water on the garden and as an emergency drinking supply, so was concerned about water quality. Mistake #2: the roof wasn’t inspected or cleaned prior to plumbing into the tank. Screened rainheads were cut into the four downpipes. Three are easily accessible; the fourth is cut in 3.3 m above ground (mistake #3), requiring an extension ladder and assistance to remove the screen and clean it. Result: six months later, it hasn’t been cleaned. (One plus: the rainheads were not glued into the pipes.)
It was with the first-flush diverter that things really went awry. The supplier calculated that about 230 litres of water needed to be diverted given the size of the roof and the relatively small tank. That required a three-metre length of 300 mm pipe that needed to run underground: not cheap, and a lot of digging too. Fittings were bodged to save costs and the bottom of the system was sealed with a rubber gasket fitted to a trickle-fed nozzle that discharged the diversion chamber. The diversion chamber was at the bottom of the whole system, about 1.2 metres lower than the bottom of the tank. The wrong components were installed and the ball didn’t block the diversion chamber once it was full. The water pressure from heavy rain blew the rubber gasket clear off the pipe: water gushed out and nothing reached the tank. How to count the mistakes here? (#4) Well-meaning and helpful suppliers lacked experience with first-flush diverters and (#5) the tradesperson was completely out of his depth. And out of patience too, which made for a tense environment.
Site visits ensued from the local agent and the supplier – and by Massey University’s Stan Abbott, with two French PhD students in tow. Upshot? The problems outlined above were identified. The first-flush diverter was dug up and the fittings scrapped. A Marley first-flush diverter kit was fitted to the 300 mm pipe, a new ditch dug, the correct components installed and buried at the exact 12 degree angle specified by Stan … and breath was held until the next rain, at which point the system operated correctly.
But it wasn’t entirely over. Months later, problems emerged with the positioning of the tank. The drainlayer didn’t use fittings to connect the inlet and outlet pipes into the tank (#6); rather he’d made a rough hole with a jigsaw (rather than a hole saw)(#7), and used a cheap silicone substitute to patch around the holes (#8). Exposed to UV, this compound quickly broke down and the tank started leaking around the inlet pipe. These pipes should have been plumbed in beside the access hatch. Instead they were on the opposite side of the tank (#9) – so in order to repair the pipe fittings, someone had to climb into the tank, two-thirds full of water. That someone was the slender homeowner, because the plumber called in to fix up the shoddy work was too burly to fit through the hatch!
Rainwater Harvesting
/in Building and Technology, Magazine ArticlesPart 1
Water is a precious resource, the stuff of life itself. Around the world, water aquifers are drying up, groundwater is being contaminated and irrigation schemes are stressing the river systems that span continents.
Yet here in New Zealand, we usually take water for granted; we turn on the tap, out comes water we can drink.
Harvesting rainwater has long been the norm in rural areas that reticulated water doesn’t reach, yet it’s still not common in New Zealand’s urban areas. We lag far behind Australia, where drought and pressure on water supply are motivating changes in household water use and government subsidies for rainwater collection. More than half of Adelaide households have rainwater tanks for example.
There’s a lot to consider about how you harvest rainwater. But for urban households already connected to reticulated water, first you need to consider why you might do that.
Water security
Your family needs water to survive an emergency. That’s the single most compelling reason to have some means to harvest rainwater. Urban water researcher Martin Payne lives in Wellington city, where water comes from Kaitoke in the Hutt Valley. “The pipeline is about 45 km long and it crosses a major fault line three times. In an earthquake, it is very likely the network will be significantly affected. It may be years before some houses can be connected to the water network again.”
How much water do you need in an emergency? Some guidelines say three litres per person per day, but that’s the absolute bare minimum for short-term survival, says Martin. WHO guidelines call for 20–40 litres.
A four-person household may need at least 80 litres of water per day. “That’s 80 kilos you have to transport, every day, in whatever containers you have available,” warns Martin. “In my opinion, that’s what will drive half the population out of the city following an emergency.”
The Wellington Region Emergency Management Office (WREMO) has partnered with a local manufacturer to make 200-litre rainwater butts available at cost to Wellington ratepayers. The butts are cheap, and quick and easy to connect to a single downpipe – no plumber required.
In an emergency, boil the water gathered from a simple system like this before drinking it, or use an additive. You may prefer a hydrogen peroxide solution like Pour N Go to household bleach.
Is 200 litres enough storage? It’s a start, says Scott Dray, WREMO emergency management adviser. “We still encourage people to store emergency water supplies in containers. And here in Wellington, we don’t usually go more than a week without rain [that would replenish the rainwater butt].”
Water conservation
Harvesting rainwater from your own roof is a way to get around water restrictions applied by local bodies in many parts of the country. Many local bodies have introduced water meters, so reducing your use of town supply will save money on water charges.
However, there are bigger issues that go beyond a simple dollar calculation. “City surfaces are increasingly impermeable, so rainwater becomes stormwater and it’s shed quickly,” says Martin. High volumes are released quickly into urban streams, disturbing the ecosystem and reducing water quality.
There’s a lot of infrastructure and cost involved in treating reticulated water to drinking water quality – but very little of that water is used for drinking. Much of it is used to flush toilets.
Martin’s modelling suggests that a Wellington household with a modest 1000–3000 litre rainwater tank (plumbed to the laundry, toilet and outside taps), combined with reasonably efficient water use, could still halve its use of potable water.
Water quality
Rainwater may be preferable to town supply in places where reticulated water is poor quality. (Adelaide has so many rainwater tanks because of the salinity of the Murray River, from which town supply is drawn.) And some organic gardeners prefer to use rainwater rather than chlorinated town water on their gardens.
Rainwater tanks: things to consider
So you want a rainwater tank? Invest in some research and planning before opening your wallet.
This advice assumes your home is connected to reticulated water. (Stand-alone systems will be covered in the next issue ofOrganic NZ.) Experts and authorities want you to use that potable town supply in your kitchen and for showering/bathing. Plumbing your tank into your toilet, laundry and outside taps will typically meet 65 percent of your household water needs.
All models and brands are mentioned only as examples to help you begin your research.
The cheapest and simplest option, suitable for emergency water supply, is to connect a small plastic tank to a single downpipe, anything from 200–1000 litres, and empty it using a bucket, watering can or drip-fed irrigation system. Costs will be limited to the tank, simple fittings and minimal site preparation.
Slimline tanks like an 800-litre tank by Urba Water or 1020-litre Aqua Tank (SL01000) will fit under your eaves, take up less space, and multiple tanks can be fitted in series. They can be connected to a downpipe using a Superfill Deluxe device from Rainline Water Solutions, another an all-in-one fitting (screen/inlet/overflow). Tall tanks like these should be strapped to reduce the risk of damage in an earthquake.
You may want a bigger tank if you have room, collection area, and can take advantage of contour to gravity feed to gardens – or if you need to buffer stormwater discharge on site. You’ll pay more for fittings and drainpipe and probably need a plumber. You’ll need to consider how you’ll handle overflow when the tank is full. If stormwater is currently discharged into the city system, plumb the overflow into existing piping.
It’s a big jump in cost and complexity to the next step, plumbing water into your house: more fittings and pipe, plus a pump. Beware of plumbers trying to sell you pumps oversized for your system.
What sort of tank?
The many options available include concrete, timber, stainless steel and plastic tanks in many colours and shapes. If it looks good, expect to pay a premium.
Polyethylene is considered among the most inert of plastics and the tanks are long lasting; many are warranted for 15 or even 20 years. Still, some people think a plastic tank affects the taste of the water or have concerns about possible leaching of chemicals. Marine-grade stainless tanks are available (in smaller sizes) – nice if you can afford it.
If you need to bury a tank, you’ll need a concrete one. Some, not all, plastic tanks can be dug in a little bit, typically 0.6 m, to reduce their height.
In a small urban section, getting a concrete tank on site may be impossible or expensive. The other alternative is to build in situ. It’s a nice DIY project if you’re handy. Some people like concrete because it neutralises the natural acidity of rainwater.
Rectangular tanks can fit into spaces round tanks can’t, but must be strengthened with special reinforcing. This increases weight and cost.
You have more options if you’re incorporating a tank into a new build, such as bladders that fit underneath decks, or tanks buried near the house site.
Rachel Rose is establishing an urban permaculture property in Whanganui.
Rainwater collection 101
1. Calculate your roof area in square metres and estimate the area draining to each downpipe.
2. Assess your roof’s suitability for water harvesting. Ensure there is no lead-based paint or fixings present. Prune back overhanging trees to reduce leaf fall and fouling by birds or small animals.
3. Look up NIWA data for your region at http://bit.ly/XSLeOt and record your area’s rainfall (yearly average and by month).
4. Use this formula to calculate the volume of water you could potentially harvest: Annual rainfall x catchment x co-efficient %. Here’s an example, using the author’s house in Whanganui: 918 (mm rainfall) x 160 (roof size in sq m) x 0.9 = 132,192 litres per annum. The formulas get more complicated when you factor in first-flush diverters! Marley literature provides advice for calculating this: www.marley.co.nz. The co-efficient relates to the impossibility of harvesting all water that lands on your roof. In heavy downpours, some water will spill over gutters. Some will evaporate. If you have an absorbent roof material like concrete tiles, the co-efficient will be much less: seek further advice. Also review NIWA data for number of days of rain and consider how long your region may go without any rainfall, to calculate how long you may have to store water for.
5. Explore what space you have available for siting a tank, taking into account downpipes and overflow.
6. Check your council’s regulations about siting tanks. A tank not plumbed into the house is unlikely to require a consent, but may have to comply with regulations about placement.
Wooden barrels have been used for centuries to collect and store rainwater, and are still seen occasionally.
Now other materials are more common for tanks: plastic, concrete and stainless steel – see page 23 ‘What sort of tank?’
to get you thinking about what would work best in your situation.
This 15,000-litre plastic tank is huge for a suburban section but melts into the permaculture garden.
The tank collects rainwater from the roof of the house and pumps water back into it. The house is also connected
to town supply but can be switched entirely to rainwater if necessary.
Photo: Rachel Rose
Is your soil toxic?
/in Gardening, Magazine ArticlesTremane Barr in his vege garden after the February 2011 earthquake.
His copy of Organic NZ arrived in the mail a few hours before the quake.
(Photo: Tremane Barr)
The Canterbury earthquakes of 2010 and 2011 have shaken the lives and properties of many that live here, but one aftershock that has come as a complete surprise to the public was the release of information by the regional council – Environment Canterbury (ECAN) – that at least 11,000 properties might have some form of toxic contamination.
The following content is only available to members. Join us for access.
What’s in your milk? A consumer guide
/in Health and FoodMilk has been an important source of nutrition for generations of New Zealanders. There is a huge range of types of milk choose from today, but not all of it provides the same benefits. Kyra Xavia investigates.
This article was featured in the July/August 2014 issue of Organic NZ magazine, under the Health and Food section.
We hope you enjoy this free article from OrganicNZ. Join us for access to exclusive members-only content.
Under current regulations, milk sold over the counter must be pasteurised. It commonly goes through additional processing to standardise its taste, texture and appearance, extend shelf-life and boost market appeal, all of which alter its composition and nutritional status. Conventional and intensive farming practices also negatively affect milk quality, and so can storage. Fluorescent light in supermarket chillers destroys up to 50% of vitamin C in milk stored in clear containers. As with all food, the fresher and less processed it is, the better.
Raw
Raw milk is totally unprocessed, tasty and wholesome, containing a full complement of vitamins, minerals, enzymes and beneficial bacteria, with just the right ratio of protein, fat and carbohydrates for optimal nutrient absorption. More effectively digested and tolerated than pasteurised and homogenised milk (many people with lactose intolerance and dairy sensitivities can digest raw milk), when drunk regularly, it can relieve the symptoms of asthma, eczema and hayfever, and even prevent these conditions from developing.1
Raw milk also helps recolonise the gastrointestinal system with friendly bacteria, which can rebuild and strengthen the immune system. In New Zealand, the only legal way for farmers to sell raw milk is directly to customers from their farm gate. Village Milk imports automated raw milk dispensing machines which make it easier for farmers selling from the farm gate (see www.villagemilk.co.nz and ‘Raw milk success story’ by Annie Wilson in Organic NZ Sept/Oct 2012).
Pasteurised
Pasteurisation heats milk while under pressure to temperatures above 72ºC for 15 seconds in order to destroy potentially harmful bacteria. Although manufacturers claim this does not significantly change its qualities, so many of the health-giving substances present in raw milk are heat sensitive. (For a full list visit www.euphory.com/raw-milk-benefits) Pasteurisation also destroys or deactivates most enzymes in milk, including the majority of enzymes necessary for the digestion of milk and the absorption of calcium. It destroys beneficial bacteria (probiotics) and lactic acids, diminishes vitamin content; denatures whey proteins, and harms important immunoglobulins which provide resistance to many bacteria, bacterial toxins and viruses. Last but not least, pasteurisation damages butterfat, which boosts immunity, protects against disease, and prevents stiffness in joints.
Photo: Kyra Xavia
UHT
UHT stands for ultra high temperature. Milk is heated up to 150°C for 5 seconds, killing all living enzymes and bacteria. This sterilisation process enables UHT milk to be conveniently transported and stored for months without refrigeration, but UHT not only significantly changes the taste, appearance and structure of milk (denaturing proteins and oxidising milk sugars), it also causes the marked loss of the amino acid lysine, vitamins B9 and C, and a reduction in other water-soluble vitamins, folate-binding protein (crucial for the assimilation, distribution and retention of B9 in the body), vitamin A, and calcium.
Organic
Healthy soil, nutrient-dense, antioxidant-rich pasture, and rotational grazing methods provide cows with an optimal diet, giving organic milk its nutritional advantage, full taste, and slightly yellow colour. Recent studies show that organic milk has significantly higher levels of omega 3 essential fatty acids (up to 62%), than conventional milk. Omega-3 EFAs play a crucial role in development and are particularly important for pregnant women, infants and children.2 Organic milk is safer for humans, and better for ruminants and the planet, because sustainable systems use natural compost and soil enrichment methods, and cows eat a completely natural diet. Although organic milk is healthier, this applies only to whole (unhomogenised) milk, not processed products. Nor should truly organic milk be ‘enriched’, ‘fortified’, or contain additives.
Non-organic
Nutritional deficiencies in the soil and diet result in the same deficiencies in milk. Land that is chemically treated and dependent upon synthetic nitrogen fertilisers will produce inferior feed and living conditions for cows. Sadly, it’s standard practice with many conventional and all intensive dairy farms in New Zealand to supplement cows with genetically engineered (GE) soy, corn, and/or cottonseed meal, as well as palm kernel expeller (a waste product from unsustainable palm oil extraction.) Not only that, the various pesticides, herbicides, fungicides, nitrate inhibitors, antibiotics, hormones (for more frequent and shorter calving cycles, to increase milk production) and chemical cleaning agents used in conventional farming, pollute the food chain. Permeate (a waste product from cheese-making and the ultra-filtration of milk), is added to certain blue-top (homogenised) or ‘lite’ varieties to cheaply standardise milk for consistent levels of fat and protein year round. As it’s derived from milk, it’s not considered an additive and therefore escapes labelling.
Whole
Whole milk is non-homogenised – the old ‘silver top’. Contrary to what nutritional experts have been saying for years, research reveals that the dietary intake of saturated fats does not contribute to heart disease and obesity. In fact, it’s the opposite. Saturated fats, especially those found in dairy products, have been proven to be protective, even preventing these conditions from developing.3,4 Whole milk keeps the body lean by providing a sense of satiety (satisfaction), regulating appetite, stabilising blood sugar, boosting metabolism, and improving the assimilation of minerals and nutrients.2,3
Homogenised
Most milk is homogenised unless labelled whole or non-homogenised. The homogenisation process forces whole milk through small orifices under very high pressure to make fat globules so small they disperse evenly, preventing cream from rising to the top. This alters the colour, flavour and most likely, the nutritional status of milk. Homogenisation lengthens shelf life by 11 days or more, and makes reduced-fat milk appear less watery. Homogenised milk has been incorrectly blamed as a leading contributor to the development of heart disease, cancer and diabetes, but more research is needed to prove that it is benign.
‘Lite’, trim or skim: low-fat
These products have had the butterfat removed and are lower in calories and nutrients than whole milk. Although they are targeted at consumers concerned about health and weight loss, they are in fact linked to illness and obesity. (Skim milk used to be considered a waste product and is so effective at weight gain it’s been used to fatten pigs.)3,4,5 Butterfat removal strips away important nutrients. Adding extra calcium and vitamin D afterwards (misleadingly marketed as ‘enriched’ milk) is pointless because milk fat is required by the body to absorb both substances, along with other nutrients. Low-fat milk has a higher glycemic index rating than whole milk and causes fluctuations in blood sugar. Without butterfat, milk is blue, watery and chalky tasting, lacking the pleasant full mouthfeel and taste of whole milk, so manufacturers add processed skim milk powder and/or milk solids (protein, lactose and minerals.) Homogenisation of whatever fat remains makes the milk seem less thin.
A1 and A2
The A2 type of beta-casein component of milk protein is believed to be better for humans because, unlike A1 (a mutation of A2), consumption of A2 milk is not linked to heart disease, type 1 diabetes, autism, schizophrenia and some autoimmune diseases.6 A1 beta-casein may be particularly problematic to infants and those with a leaky gut (hyper gut permeability.) Some people who believe they are lactose intolerant and dairy sensitive may instead be reacting to A1 beta-casein. Heirloom breeds such as Jersey, Ayrshire, Brown Swiss, and Milking Shorthorn tend to produce milk with more A2, with some Guernsey producing 100 percent A2, while breeds like Holstein, Friesian and Kiwicross (preferred by large dairy farms for their high milk output) produce more A1. Many organic dairy farms have heirloom breeds, which produce milk with high butterfat.
In summary: It’s well worth sourcing raw, whole organic milk from a local farmer. Failing this, choose organic unhomogenised whole milk.
Kyra Xavia is a freelance writer, photographer and qualified nutritionist, naturopath, herbalist, homeopath and aromatherapist.
References
1. G Loss, et al., 2011, ‘The protective effect of farm milk consumption on childhood asthma and atopy’, J of Allergy and Clin Immun., 128:4
2. C Benbrook, et al. 2013., ‘Organic production enhances milk nutritional quality by shifting fatty acid composition’, PLoS ONE 8(12)
3. S Holmberg and A Thelin, 2013, ‘High dairy fat intake related to less central obesity’, Scand J Prim Health Care, 31(2)
4. R Chowdhury, et al., 2014, ‘Association of dietary, circulating, and supplement fatty acids with coronary risk’, Ann Intern Med., 160(6)
5. A Oliver and E Potter, 1930, ‘Fattening pigs for market’, Oregon State Agricultural College, http://hdl.handle.net/1957/14694
6. M Sodhi, et al. ‘Milk proteins and human health: A1/A2 milk hypothesis’, 2012, Indian J Endocrinol Metab.,16(5)
To source raw milk
Ask around or contact your closest Weston A Price Foundation chapter.
Further reading
Jo Robinson, Eating on the Wild Side (2013)
W Price, Nutrition and Physical Degeneration (first published 1939)
R Schmid, The Untold Story of Milk (2009)
K Woodfood, Devil in the Milk (2009)
D Gumpert and J Salatin, The Raw Milk Revolution (2009)
W Douglass, The Raw Truth About Milk (2007)
B Macfadden, The Miracle of Milk (1923)
Websites
www.eatwild.com
www.raw-milk-facts.com
www.realmilk.com
www.westonaprice.org
NZ Alliance for Raw Milk: www.facebook.com/nz.arm
Amber light for dung beetles?
/in Farming and Horticulture, Magazine ArticlesCopris lunaris: one of the dung beetle species approved for release in New Zealand. The dung beetle is the only insect known to navigate using the Milky Way.
Photo: Siga / Wikimedia Commons
Dr Nick Waipara explores the biosecurity issues of introducing exotic dung beetles onto organic farms in New Zealand.
Recent months have seen the first of a series of releases of exotic dung beetles on New Zealand farms. Organic farmers potentially have much to gain from dung beetles, but may also be vulnerable should dung beetle introductions have unwelcome side-effects. So, should organic farmers (and the rest of us) be concerned about new dung beetle introductions, and if so, why?
The following content is only available to members. Join us for access.
GE food: A Trojan horse – what is it sneaking into us?
/in Farming and Horticulture, Health and Food, Magazine ArticlesMinolta DSC
Obviously the admonition to ‘never look a gift horse in the mouth’ was around in the time of the Greek–Trojan war. The Trojans were not aware of the dangers of accepting things at face value or they would not have been conquered. Today, consumers are being presented with food products that are not as portrayed by their proponents and also with potentially dire consequences.
I refer to genetically engineered (GE) crops, in particular to Roundup Ready (glyphosate-resistant) and Bt crops (engineered with the bacteriumBacillus thuringiensis). These crops are designated ‘safe’ for human and animal consumption by New Zealand’s regulatory authorities: Food Standards Australia New Zealand (FSANZ) and the Ministry of Primary Industry (MPI), despite the transgenic crops not having undergone even adequate safety tests independent of the companies developing and marketing them, e.g. Monsanto, Dow and Syngenta.
The following content is only available to members. Join us for access.
The ‘dirty dozen’ – latest update
/in Health and Food, Magazine ArticlesWhich foods in New Zealand are more likely to have pesticide residues?
What’s wrong with pesticide residues in food?
How can pesticide residues in food be reduced?
Alison White answered these questions in Organic NZMay/June 2010. Here she revisits them and gives us an update.
Which foods have the most pesticide residues? Grapes, celery, a range of fruit, pak or bok choi, spring onions, cucumber and bread are all ranked in the top dozen of foods available in New Zealand which are more likely to contain pesticide residues. Close contenders behind this ‘dirty dozen’ are apples, spinach, olive oil, muesli and tomatoes.
The following content is only available to members. Join us for access.
Hemp: The comeback crop for building
/in FeaturesHemp is an ancient crop, grown for its fibre and put to thousands of uses. Unreasonably lumped in with cannabis, hemp was supplanted and restricted for nearly a hundred years – but it is now being heralded as an outstanding building material for our time.
We hope you enjoy this free article from OrganicNZ. Join us for access to exclusive members-only content.
New Zealand’s first house made of hemp will be finished this summer. Lance and Miranda Palmer are building a 195 m2 home in Taranaki using hempcrete for their walls.
Why hemp? “I wanted a home that would breathe naturally,” explains Lance. “When we learnt about hemp, it ticked all the boxes. It’s unusual in that it’s both a great insulator and yet provides a lot of thermal mass.”
Benefits for building
Hemp as a building material delivers an impressive list of benefits, say proponents like Greg Flavall, a builder and entrepreneur encouraging the use of hemp in New Zealand. He claims hempcrete is a carbon neutral or even carbon negative material. The fast growing hemp sequesters carbon and, once processed, the fibres are mixed with a lime and cement binder to create ‘hempcrete’. The lime continues to harden over time, absorbing more carbon as it calcifies. Some 110 kg of carbon is locked up per cubic metre of hempcrete, according to UK consulting firm Hemp-Lime Construct.
Hemp building materials are lightweight, insulating, and highly breathable, producing homes with excellent air quality, according to Greg. It’s fireproof and rodent and insect resistant. It’s extremely durable, with an expected lifespan of several hundred years. Hemp is also versatile; just vary the ratio of binder to make floors, walls, or insulation. And it can be deconstructed and recycled in another building project!
What it isn’t, is load bearing: hempcrete is being used in New Zealand as infill between timber structural framing.
Eco-architect Graeme North also has an interest in hempcrete but takes a more cautious view. He questions the claim about carbon neutrality, saying that manufacturing lime produces more carbon than it subsequently absorbs. “Claims of both insulation and thermal mass need to be considered carefully,” he warns, as it depends on the thickness and density of the wall.
Hemp growing in Taranaki
Different varieties of industrial hemp are grown depending on the desired yield (seed, fibre or fabric). They are alike in having extremely low levels of tetrahydrocannabinol (THC), the active ingredient in the Cannabis sativa grown for marijuana use: 0.3% compared with 3–22%.
A regulatory scheme was established in 2006 that makes it legal for license holders to grow, process and distribute hemp in specific circumstances. A grower must send crop samples to a lab before harvesting, to ensure THC levels are below prescribed limits. Crops not meeting this requirement may be destroyed. As at 23 September 2013, 27 licences to grow industrial hemp have been issued by the Ministry of Health, with a further two being processed.
Last summer, two Taranaki farmers working with Greg Flavall got their hemp licenses and 4.45 ha was sown, including at Avonstour, an organic, rare breeds family farm east of Stratford.
From field to house
Hemp is a fast-growing and robust annual broadleaf, with a root system that can extend two metres. It is naturally insect and pest tolerant and may not require fertilising.
Hemp’s history spans some 12,000 years, having been grown in Asia and the Middle East for fibre to make fabric, cloth and rope. It was grown extensively in the US from the seventeenth century. But its cultivation was outlawed in the US and UK in the 1920s and 30s when fears about cannabis use were running high, and fell away in Europe last century as hemp was supplanted by newer, synthetic fibres.
After harvesting, the plant is retted: soaked in water to loosen the fibres from the woody core. The fibres are separated out in a mechanical process called decortication before the stem is dried and chopped to produce shiv. To make hempcrete, the shiv is mixed with a small amount of hydrated lime-rich binder. Greg advocates a 5:1 mix of lime and cement, which means the binder is about two percent of finished volume. Natural pigments can also be added to create striking natural colours or patterns.
Greg runs workshops designed for owner builders, architects and building professionals, who get their hands on the raw material, building their own small hempcrete block. This is a miniature example that shows how hemp walls can be constructed, by lightly tamping hempcrete in place in between single or double-sided formwork. “Professionals come along and say, ‘Wow, this isn’t difficult at all!’,” grins Greg.
Houses that Greg is involved with are using single-sided forms. “We’re framing into the interior edge of a [400-450 mm] thick wall and lining the interior of the house with magnesium oxide building board, a gib replacement. Mag oxide board is inert, fire-resistant and it breathes with the hemp,” he explains.
There are other possibilities. “Boxing both sides around a timber frame is common in many parts of Europe,” says Graeme. “The wall is then clad for protection from the weather, especially wind driven rain, or simply plastered with lime plasters. Inside can be left as is, or any breathable natural finish [applied].”
Hemp can also be used as loose fill insulation and a flooring material. In Europe, large commercial buildings have been built with pre-fabricated hemp wall panels hoisted onto a post-and-beam structure.
Buildings made from hemp can have any kind of look you want, says Greg. For instance, the first US house built of hemp materials, in Ashville, North Carolina in 2010 – with which Greg and his Canadian based company were involved – is a high-end example of striking contemporary architecture (see www.gizmag.com/first-us-hemp-house/17115/ for photos and construction details). But hemp is also just as suited to natural renders that make a feature of the colour and texture of the natural fibre.
Notwithstanding information you’ll find on the internet, Greg is adamant that hemp is not suitable as a foundation material. “We know from history that hempcrete doesn’t work below ground. If subjected to constant moisture, it will break down and the lime will not carbonate. It’s the carbonation that preserves the hemp.”
Hemp construction underway
The Palmer house is being built on concrete foundations topped with insulated concrete forms. Building consent applications for this and other hemp houses have used alternative solution provisions provided in the New Zealand Building Code. The Palmer house was approved by the New Plymouth District Council in 20 days. “We introduced the building method first and asked the Council what information they wanted from us,” says Lance. “They were really good to deal with.”
“The building inspectors were pleased to see lime coming back,” says Greg. “We provided documentation from the US and Europe – and a sample block! The fact that the hemp was the aggregate was of no importance.”
The first New Zealand houses of hemp are being built with shiv imported from Europe but Greg wants to establish a Taranaki based co-op (a ‘hemp village’) that will grow and process hemp and produce local hemp products.
Meanwhile, plans are being drawn up for homes made with hemp and building consent applications have been lodged with Auckland and Waikato councils. The 14 projects between Dunedin to Northland range from expensive, architecturally designed homes to owner-builder homes that will be slowly completed as funds and time permit.
More information
Interested in growing hemp in New Zealand? Growers, processors and suppliers require a license, administered by the Ministry of Health. Start here:
www.health.govt.nz/our-work/regulation-health-and-disability-system/medicines-control/hemp-industrial-hemp
Rachel Rose is establishing an urban permaculture property in Whanganui.
Proudly published by the Soil & Health Association NZ
Proudly published by the Soil and Health Association NZ