Page 15 - Lake Roosevelt Forum 2020 Public Guide

CALCULATING LEAD, CANCER, AND NON-CANCER RISKS
Calculating Lead, Cancer, and Non-Cancer Human Health Risks
The graphic below shows exposure pathways to people from chemicals entering the UCR and settling in the Upper Columbia Valley.
Depending on the pathway, exposure to chemicals of concern could
come by ingestion (oral), dermal (skin), or inhalation (breathing-
in). For each population of concern (residents, recreational visitors,
workers and tribal members), multiple exposure pathways were evaluated. The range of chemicals evaluated included metals, pesticides, human-made compounds like PCBs and PBDEs contained in industrial and household products, and toxic substances like dioxins/furans that are a byproduct of burning waste or produced as part of a manufacturing process.
The Human Health Risk Assessment (HHRA) uses the outcome of site- specific investigations to calculate possible lead, cancer, and non- cancer human health risks. Critical to informing calculations was an extensive Recreational Uses Survey conducted in 2010-2011 that showed how often recreational users in the Upper Columbia Valley consume fish, visit beaches, and participate in other recreational activities.
Upper Columbia Human Health Risk Assessment Exposure Pathways
Contaminant Sources
Smelting operations in Trail, Canada are the primary source of metals contamination. Effluent and slag were released into the river and emissions into the air.
Other contaminant sources include pulp and paper production
in Canada and previous localized mining operations.
Water
Contaminants from effluent (wastewater) and slag moved downstream, settling in sediment on the river bottom, banks and beaches. They can also attach to fine particles that travel through the water column.
Air
Emissions drifted south, causing atmospheric deposition
in the Northport area (Upper Columbia Valley).
POTENTIAL HUMAN EXPOSURE AREAS
Bioaccumulation
Sediment contaminants can directly impact or accumulate in the tissues of worms, clams, insect larvae and other organisms (the benthic community) that inhabit the lake bottom.
RIVER BASED
Sediment
Beaches
Relict Floodplains Subsurface Beach Areas
Surface Water
Fish, Shellfish & Wildlife Consumption
Fish Waterfowl Mussels Amphibians/
Reptiles
Species can accumulate contaminants in their tissue and organs, and these toxic chemicals can move up the food chain to humans, birds, and other species consuming fish.
UPLAND BASED
Air
Outdoor Indoor
Soil & Direct Soil Contact
Residential Properties
Tribal Allotments Public Lands
Terrestrial Plants
Game Birds & Mammals
Biomagnification & Food Chain
Organic contaminant concentrations (like PCBs) and mercury can biomagnify (increase) in the tissues of species as they move higher in the food chain, e.g. stonefly to fish to wildlife to humans.
METHOD OF HUMAN EXPOSURE
Dermal (Skin) Contact Inhalation Consumption Incidental Ingestion
Crayfish
15