Chloride Trends In Ontario Lakes And Streams

Session: 55. - Solutions for Lake Ontario: Addressing the Human Footprint on Regional Water Quality

Shelley Arnott, Queen's University, [email protected]
Martha Celis, Queen's University, [email protected]
Anna DeSellas, Ontario Ministry of the Environment and Climate Change, [email protected]
Claire Holeton, Ontario Ministry of the Environment and Climate Change, [email protected]
Chris Jones, Ontario Ministry of the Environment and Climate Change, [email protected]
Georgina Kaltenecker, Ontario Ministry of the Environment and Climate Change, [email protected]
Michelle Palmer, Ontario Ministry of the Environment and Climate Change, [email protected]
Andrew Paterson, Ontario Ministry of the Environment and Climate Change, [email protected]
James Rusak, Dorset Environmental Sci. Ctr., [email protected]
Ryan Sorichetti, Ontario Ministry of the Environment and Climate Change, [email protected]
Aaron Todd, Ontario Ministry of the Environment and Climate Change, [email protected]
Norman Yan, York University, [email protected]
Huaxia Yao, ON Ministry of Environment and Climate Change, [email protected]

Abstract

In partnership with Ontario Ministries and universities, the Ontario Ministry of the Environment and Climate Change (MOECC) has monitored chloride in lakes and streams for more than four decades. Here we present long-term trends in chloride concentrations from various monitoring programs across Ontario. It was found that chloride concentrations in impacted lakes and streams are significantly increasing compared to reference systems. The greatest increases in concentration were in areas of high human population and road density. A positive significant relationship was found between road density and median chloride concentration in 142 streams sampled between 2004 and 2008. Despite the observed increasing chloride concentrations, many lakes and streams in Ontario remain below the Canadian Water Quality Guideline for the protection of aquatic ecosystems. Some streams in southern Ontario associated with high population and road density have concentrations that exceed this standard, or may soon if current rates of increase continue. The ecotoxicity of chloride on aquatic organisms remains uncertain, as evidence suggests regional differences in species-specific tolerance to chloride levels. These results suggest long-term road salt use is contributing to an increase in lake and stream chloride concentrations, which may have significant ecosystem health implications for aquatic organisms and their habitats.

1. Keyword
monitoring

2. Keyword
ecosystem health

3. Keyword
water quality

4. Additional Keyword
road salt

5. Additional Keyword
chloride

6. Additional Keyword
Canadian water quality guideline