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The e-coli contamination of
Walkerton’s water supply in May, 2000 which resulted in the illness and
death of many Walkerton residents appears to have originated from a
livestock operation proximate to the town’s wells. Evidence heard by The
Walkerton Inquiry indicates that this contamination occurred despite
compliance by the livestock operation with present guidelines and best
management practices concerning manure storage and spreading. What is the
possibility of similar well contamination elsewhere? Is present manure
management regulation sufficient to address this risk? If not, how should
manure management be regulated to protect drinking water supplies?
A coalition of rural
landowner groups concerned about manure management issues and the Sierra
Club of Canada (the Alert-Sierra Coalition) has recently argued before The
Walkerton Inquiry that present manure management guidelines and best
practices are inadequate to protect Ontario’s surface and groundwater
resources and that a systematic, coordinated risk-based approach to manure
management regulation is required for the protection of this resource.
Studies presented to the
Inquiry have established that over 150,000 wells in Ontario may be
contaminated by bacteria in excess of maximum acceptable levels established
under the Ontario Drinking Water Objectives. These studies indicate that
this contamination results twice as frequently in fields where manure is
routinely applied. Evidence heard by the Inquiry also indicates that the
pathogens contained in the manure may survive in the soil for months or
years and may travel through the soil to enter underground aquifers many
kilometers from their point of origination.
The position of
Alert-Sierra is that, even where mandated by municipal bylaw, nutrient
management plans are ineffective to prevent manure contamination of water
resources because they focus on the nutrient requirements and capacity of
growing crops and fail to address the pathogens contained in manure and the
fate of those pathogens in the environment. OMAFRA has acknowledged in
evidence before the Inquiry that many of the variables relevant to the
ability of the subsurface soils at a particular site and within an entire
watershed to absorb manure are not considered as a part of nutrient
management planning. Similarly, present voluntary best management practices,
if followed, provide no assurance of protection of water resources because
they do not require consideration of site-specific hydrogeological
conditions prior to the release of manure into the environment. In
announcing the new Nutrient Management Act, 2001, the Province has proposed
by regulation to simply make mandatory nutrient management planning,
agricultural best management practices and environmental farm plans.
Alert-Sierra argues that such a limited regulatory approach may be no more
successful than the present regulatory regime in preventing contamination of
drinking water supplies.
Alert-Sierra’s position is
that responsible management of Ontario’s surface and groundwater resources
requires that the contamination risks of specific development be assessed,
taking into consideration the vulnerability of resources in the area of the
proposed development and the nature of the development proposed. This
risk-based approach to water resource management should include regional
aquifer vulnerability mapping and site-specific hydrogeological
investigation before permitting development of new agricultural facilities
for manure storage or the spreading of manure. The risk assessment should
take into consideration factors affecting the absorption capacity of the
on-site soils and watershed as a whole in the area of spreading. These
factors may include climatic and soil conditions; manure composition; time
and rate of spreading; the geology and hydrogeology of the site, plus
vulnerability of the local aquifer to contamination; proximity of the site
to wellhead recharge areas; and, existing aquifer and surface water quality.
Implementation of this
risk-based approach to water resource management will necessitate a
comprehensive aquifer mapping and vulnerability assessment program with
continuing monitoring. Well-head recharge areas must also be defined. It is
Alert-Sierra’s position that only with such a comprehensive regulatory
regime in place can current and future groundwater impacts of manure storage
and spreading be evaluated. In areas where aquifers are considered to be
vulnerable to contamination, such regulation will require site assessment
with the risks of agricultural development to be controlled through
restricted approvals of specific manure management practices. |