May 2006
Summary of Lake Whatcom Risk Assessment Project
by Christina Maginnis
Christina Maginnis is an environmental science graduate student at Western Washington University whose research focuses on integrating ecological and human health risk assessment models for a drinking water source. She worked for the city of Bellingham Public Works Department conducting environmental site assessments and restoration projects on Lake Whatcom watershed properties, working with the mayorÂ’s Watershed Advisory Board, assessing stormwater outfalls for dry weather flows and assessing erosion control measures for construction sites. She also coordinated the statewide acid rain monitoring project, and the stream continuity project for the Water Resources Research Center in Amherst, MA.
An integrated human health and ecological risk assessment will be conducted for the Lake Whatcom watershed in Whatcom County, using the relative risk model. This watershed serves as the sole drinking water source for approximately 85,700 people and has multiple uses including logging, recreation and residential development.
As with any comprehensive approach to managing a water supply, there are many stakeholder groups all placing different priorities and values on this watershed. This screening level ecological and human health risk assessment will be conducted to assess the potential risks from different stressors within and outside the Lake Whatcom watershed that could be adversely impacting Lake Whatcom water quality. An evaluation will also be conducted of how these risks are affected by management tasks outlined on the Lake Whatcom Management Plan 2005-09.
There are many sources of stress to the Lake Whatcom watershed. The lake has been listed as an impaired waterbody under section 303(d) of the Clean Water Act by the Washington Department of Ecology on behalf of the United States Environmental Protection Agency for dissolved oxygen. In 2004, Lake Whatcom was listed for phosphorus, mercury, polychlorinated biphenyls (PCB) and dieldrin. The original 303(d) listing for dissolved oxygen mandated the Department of Ecology to conduct a Total Maximum Daily Loading (TMDL) study to set an allowed quantity of these listed pollutants to be discharged per day into Lake Whatcom. The study carried out during the past three years is tentatively scheduled for completion this year. The city and county managers of Lake Whatcom and its watershed are required by law to reduce pollution levels to the allowable amount specified in the TMDL.
Risk characterizations will be composed of the study region, identifying sources of stressors in each risk region, and the potential impacts to endpoints that stakeholder group’s value. These risk characterizations will provide a rank-based assessment of ecological and human health risks that exist in a multi-use drinking water supply, as well as ranking of risks associated with the Lake Whatcom Management Plan tasks for future management of this drinking water supply.
This work has been funded by a grant from the city of Bellingham. Results from this study are expected in the fall of 2006. §
