How safe is your well water?
Ominously, in the light of the Walkerton tragedy, the occurrence of E. coli in rural well water has doubled since the 1950sBy Don Stoneman
As the potload of finished cattle rolled out of the yard in the early morning sunshine, Ayr beef farmer John Gillespie nodded towards the concrete casement between the house and the barn."Had the water tested last week. It was perfect," said a grinning Gillespie, easing back into the farm routine after a weekend long reunion which brought 150 family members to the farm from across the continent.
Like many farm families across Ontario, the tragedy in Walkerton has made prominent Waterloo Region farmers John Gillespie and Mary O'Connor question the safety of their farm water supply, a 30-foot well drilled into bedrock in sandy, gravel-bottomed ground.
They are not alone. Private testing facilities have been stressed to the maximum. Furthermore, recent history shows that Ontario farm families do indeed have cause for concern about their water supply. An extensive survey of 1,300 farmstead domestic wells in Ontario in 1991 and 1992 revealed that 40 per cent contained contaminants in excess of acceptable limits.
But the ripple created when the Centre for Land and Water Stewardship at the University of Guelph released the study was quickly forgotten. A follow-up survey in 1997 brought even less attention. The Walkerton disaster, where a resource long assumed to be safe was harbouring a killer, has made drinking water safety a top issue. The Land and Water Stewardship study measured the occurrence of nitrates, which are associated with manure and nitrogen fertilizers; bacteria; commonly used pesticides; as well as petroleum possibly escaping from leaking fuel tanks.
No petroleum products were found in well water, and few herbicides were found in the tested wells. However, the occurrence of nitrates and bacteria levels beyond standards considered safe raised researchers' eyebrows. About 34 per cent of wells had too many coliforms, 14 per cent contained nitrates above the acceptable levels, and seven per cent had both bacteria and nitrate contamination.
A comparison with past surveys showed that contamination with nitrates hadn't changed in 40 years. Nitrates are a known health hazard for infants. More alarmingly, the occurrence of E. coli of all types had almost doubled since the 1950s. One third of tested wells contained E. coli at one time of the year or another.
Dave Rudolph of the University of Waterloo, who co-wrote the report, says some wells were always clean while others were always contaminated. Some wells that were 100 metres deep were contaminated, but generally, deeper wells were cleaner.
His associate, University of Guelph professor Mike Goss, resurveyed 300 wells in 1997. Then, 20 per cent were positive for bacteria types which points towards animal manure as a likely source. Between five and 10 per cent of wells were most likely contaminated by septic systems.
Wells in sandy soils, such as the Gillespies, were less likely to be contaminated with bacteria than wells in tighter, finer soils. Sandy soils are more conducive to nitrate contamination. Though Goss has gone on record that there has been a change in the percentage of wells with E. coli between the 1950s and the 1990s, he says there is no evidence to support charges that liquid manure systems are to blame for the E. coli increase.
In general, the study found that the deeper the well is, the less likely it is to be contaminated. Older wells are more likely to be contaminated than newer wells. However, at 100 feet of depth, a 100-year-old well is only a little more likely to be contaminated than a five-year-old well.
If there is a positive test for contamination, Goss says farmers should check if their well casings are in good condition. Any possibility that runoff has entered the well is a danger sign. A simple check inside the well for dead animals "will solve a lot of the problems," he says.
The Ontario Ground Water Association is (OGWA) concerned about wells that are abandoned rather than being properly decommissioned, says its president, well driller Terry Marquardt of Palmer Rapids in eastern Ontario. Financial incentives to property owners will likely be necessary, he says. "We keep raising that issue with the environment ministry," he says but admits that "we don't know how they would come up with the funding." Marquardt believes there are tens of thousands of wells in the province which haven't been properly closed and could cause contamination of aquifers. Wells that are being decommissioned should be filled with at least 20 feet of Portland cement or a similar thickness of bentonite, a natural Wyoming clay which isn't susceptible to shrinkage.
Older wells are particularly susceptible to earwig contamination, Marquardt says. They cause more grief than rodents or any other insect. Their dead bodies and droppings create bacterial contamination.
Once a new well is drilled, a homeowner still has to flush out house plumbing if there was previous bacteria contamination. Marquardt says bacteria still make their way back into wells from contaminated systems in houses, against the water flow and in spite of one-way check valves.
He recommends that farmers read the following literature: Best Management Practices, Water Wells, Agriculture and Agri-food Canada, Ontario Ministry of Agriculture, Food and Rural Affairs, One Stone Road, Guelph. 519-826-3556. BF
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The next concern - microbial infections from irrigation
The quality of the water that fruit and vegetable growers use to irrigate and wash their produce will likely be at the top of the agenda this coming winter.Ontario agriculture ministry fruit and vegetable specialist Craig Hunter, who has been seconded to the industry to work on special projects, says a proposal has been put together for funding of a project to look at the quality of all the water that farmers use when irrigating and packing vegetables and fruit.
The first part of the project is to develop a water sampling protocol so that growers can get reproducible results and relate it to the quality of the produce that comes from their farms. The plan calls for the study of water used from all sources -- deep and shallow wells, ponds and running streams. Also under consideration will be plans for remediation of contaminated water, such as chlorinating.
"There has never been contamination of fresh produce documented in Ontario," Hunter says. "The logic would say that the current practices of farmers are pretty good. But that's not sufficient these days; you have to be able to prove it."
The microbial issue has come up fast this summer for produce farmers, says Jeff Wilson, a prominent vegetable grower in Hillsburgh, Wellington County. Fortunately, the early rains mean that farmers didn't have to irrigate their berry crops and will have a chance to think about it before putting practices into effect. He thinks that it will take a season for growers to "get their heads around" the concept of dealing with possible microbial infections from irrigation.
Wilson says farmers need to know if there is microbial contamination in the ponds that they use to irrigate crops. Particularly important would be crops that are eaten raw such as berries and snow peas.
The first draft of an on-farm food safety program under development by the Canadian Horticulture Council sits unread on Wilson's desk in the scramble of the harvest season, until he has time to read it. Wilson expects that testing of water will likely be added to that plan, if it isn't already part of it. Pesticide concerns may take a backseat to bacterial concerns in this, he says. "This whole microbial thing is a little more daunting," Wilson says. "How far down do you take it?"
Wilson thinks that American growers are ahead of Canadians on these issues. The industry to the south has been tuned into the issue for a couple of years and has been considering putting all produce through a chlorinated dip. But Wilson wonders if that really improves food quality or just makes growers feel good. "Let's do this right rather than band-aid something together that may do more harm than good," Wilson says. "Fruit and vegetables are increasingly becoming a source of food-borne illnesses," says Doug Powell, an assistant professor of food safety at University of Guelph. "Producers will be the ones who lose if there is any problem. They need to demonstrate due diligence."
Powell defines that as taking all reasonable steps to ensure safe product. That may include irrigation water testing, Powell says. "There are systems where you can put a chlorinator right on the irrigator." BF
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