Manitoba Sustainable Development advises that retesting of soil from dozens of areas around central Winnipeg has found a significant decrease in the level of lead found in the soil compared to similar testing done in the 1980s and in 2007-08. This latest round of testing has confirmed there are some areas that still exceed the guidelines for lead in soil, but the risk to the public is low.
Following the results from two studies done in the Weston area of Winnipeg in 1981 and 2007-08 that showed multiple areas exceeded the Canadian Council of Ministers of the Environment (CCME) guideline of 140 parts per million (ppm) for lead in soil, the province retested many of the same areas. The CCME guidelines are national reference levels used to trigger further assessment of potential human exposures to the soil.
A total of 17 school yards were also sampled, and all but one were found to be well below the CCME guidelines, with lead levels ranging from 11.5 to 97.5 ppm.
Previous studies found a number of samples from the soil at Weston School greatly exceeded CCME guidelines. Retesting found the levels at Weston School have dropped substantially, but on average are still higher than the guideline of 140 ppm. The average concentration has now dropped to 219.3 ppm, compared to 463 ppm in 2007. Readings at Weston School ranged from 96.3 to 446 ppm.
Further testing of 20 parks and playgrounds found that 19 of the areas were well below the CCME guidelines, and only one park, Westview Park, showed levels above the guideline. The sample from Westview Park, in the Sargent Park area, was found to have a level of 439 ppm. Westview Park is a former landfill, converted to greenspace.
No exceedances were found in the Wolseley-Minto or Riverview-Lord Roberts areas. A single sample in the Glenelm-Chalmers area exceeded the guideline, but only by one ppm. Though the level of lead in soil in Point Douglas also declined significantly from previous levels, nine of the 22 samples showed levels of lead above the CCME guideline, in amounts ranging from 150 to 755 ppm.
The risk of health effects related to lead in soil is very low. It should be noted the guideline of 140 ppm is based on year-round exposure. With Manitoba’s climate, soil is covered or frozen, meaning the risk of exposure to lead in soil is present for only part of the year. At the current time, with the snow cover and frozen ground, the risk of exposure to lead in soil is negligible.
The source of lead in soil contamination may have been exhaust from cars burning leaded gasoline before the switch to unleaded fuel. Many of the areas with heavier concentrations are also near areas with heavy traffic volumes. Other common sources of lead in soil are lead in paint from older homes (usually near houses or fences) and lead in soil deposited from industrial sources. These sources of lead exposures are present in many urban centres and may be present in other parts of Winnipeg as well.
There can be some risks associated with eating food grown in soil with high lead content, particularly if soil is consumed. Manitobans are reminded to thoroughly wash and peel vegetables they grow in their gardens before eating, to wear gloves when gardening and to wash their hands after coming into contact with soil. People in areas with higher lead concentrations may want to use a raised garden and regularly replenish the soil. There is a link below to a provincial fact sheet about gardening and soil contaminants offers information for all Manitobans on how to manage the risk of lead in gardening soil.
Manitoba Sustainable Development and Manitoba Health, Seniors and Active Living are in the process of analyzing the results which were received earlier this week. Initial results for areas with increased lead in soil will be made available online soon. Staff from Public Health and Manitoba Sustainable Development are connecting with the school divisions, City of Winnipeg and the communities with increased levels of lead in the soil. Further discussions will occur over the winter months to identify any additional actions that may be suggested prior to spring.
Lead exposure may also come from other sources, such as lead paint in older buildings or lead service lines supplying drinking water. These exposures can pose a greater risk than lead in soil.
