Introduction:
Mercury is a heavy metal that is toxic to humans at low concentrations. Although very small amounts are naturally present in the environment, human activities such as coal combustion and industrial processes have increased its concentration dramatically. Once in an ecosystem, mercury bioaccumulates in organisms such as fish, and its concentration can be biomagnified up the food chain. It is a neurotoxin with a host of negative effects on the brain and nervous system in humans. Therefore, consumption of fish high in mercury is discouraged. In this exercise, we will examine data on mercury content from a variety of common fish and seafood species.
DATA SETS:
Data for Mercury_Fish: FDA 1990-2010, available at http://www.fda.gov/food/foodborneillnesscontaminants/metals/ucm115644.htm
Data for California_Lakes: Davis, J.A., A.R. Melwani, S.N. Bezalel, J.A. Hunt, G. Ichikawa, A. Bonnema, W.A. Heim, D. Crane, S. Swenson, C. Lamerdin, and M. Stephenson. 2010. Contaminants in Fish from California Lakes and Reservoirs, 2007-2008: Summary Report on a Two-Year Screening Survey. A Report of the Surface Water Ambient Monitoring Program (SWAMP). California State Water Resources Control Board, Sacramento, CA. Available at http://www.waterboards.ca.gov/water_issues/programs/swamp/docs/lakes_study/lake_survey_yr2_full_rpt.pdf
We will begin by looking at the average mercury content in a variety of fish species. These data are based on measurements taken during the period from 1990 to 2010. To display the data on the graph select “Mercury Content in Fish” from the drop-down menu. The values displayed on the graph are in ppm, or parts per million. If these values seem small or negligible, recall that mercury is toxic even at very low concentrations.
Congratulations! You have completed this activity.