The State of Colorado Water Quality Control Division, together with the Colorado Division of Parks and Wildlife (CPW), monitors fish from over 100 lake and river sites in Colorado for the presence of contaminants. Each fish tissue sample is tested for total mercury, selenium and arsenic for the purpose of risk assessment. If the mean fish tissue concentrations of these contaminants exceed levels in which the general population would have to limit consumption to less than 3 meals per month (0.3ppm for Hg), a Fish Consumption Advisory (FCA) is issued for the waterbody. The advisory includes meal frequency advice for all species of concern from a given waterbody with elevated levels of contaminants. A minimum of 10 fish and 5 composites are required in order to post an FCA. In order to assess the risk associated with each waterbody and species, the weighted mean for each contaminant is compared to established threshold values specific to each contaminant.
For more information about the Colorado Fish Consumption Program, see the following documents: