Concerns Grow Over Toxic Heavy Metals in Urban Gardens

January 21, 2015- Researchers at the University of British Columbia warn that what looks like a beautiful garden may still be contaminated, after finding elevated levels of toxic heavy metals at a Vancouver site.

Soil at an Oak Street community garden in Vancouver had concentrations of lead reaching 219 parts per million; zinc in the soil was at 456 parts per million.

The total metal contamination — including air and soil — at the 16 Oaks community garden was even higher than an industrial brownfield they measured, says Gladys Oka, lead author on the study published in the Journal of Soil Science and Plant Nutrition.

"I was surprised...that this community garden which looks beautiful, contains much more metals than the brownfield," said Oka.

The news highlights a potential problem with urban gardens. Vancouver has been encouraging people to establish new community gardens for several years, with more than 75 gardens across the city. Many are along busy streets or on former industrial sites.

Researchers don't want to make gardeners afraid, but they want to encourage the city to establish a framework for testing the soil health at urban farming sites.

The 16 Oaks' site had previously been a restaurant and parking lot, but its full history is not clear, said Oka, who notes the contamination may come from traffic at the busy street corner.

Read the full cbc.ca post here.

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