Mercury In Fish

EPA began a cooperative effort in 1995 to assemble a nationwide data base on total mercury concentrations in fish tissue. The first objective of this project was to assemble and review data on the mercury contamination in fish tissue. This step included identifying appropriate state, such as Oklahoma DE, and federal agencies and other groups with relevant data on mercury concentrations in fish. The second step in this project involved the development of a fish tissue data base, organizing relevant data to be used for future analyses. EPA focused data compilation efforts on obtaining results of state monitoring efforts during 1990-1995. These data can be used to derive estimates of tissue concentrations, determine the number and frequency of samples (see chart below) taken and analyzed by state, and calculate descriptive statistics on mercury concentrations in fish tissue. The current data base will facilitate EPA’s ability to determine additional and future data needs. In the future, the data base may be used to identify and evaluate factors affecting mercury contamination in fish.

Fish Tissue Concentrations (mg/kg) Consumption Rate (Meals per Month) Sensitive Population* Consumption Rate (Meals per Month) General Population*
< 0.5 No Restriction No Restriction
0.5 – 1.0 2 Meals per Month No Restriction
1.0 – 1.5 No Consumption 2 Meals per Month
> 1.5 No Consumption No Consumption
*Sensitive population is defined as children less than 15 and women of childbearing age (15-45). General population is men older than 15 and women older than 45. Meal size is 8 oz. with the assumption that younger children will eat smaller meals.


Below is the data for fish caught and analyzed for mercury in Oklahoma lakes.


* Lake with no advisory