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EPA's Region 6 Office

Serving: Arkansas, Louisiana, New Mexico, Oklahoma, Texas, and 66 Tribal Nations

Biomonitoring Laboratory


Picture of  biologist examining fathead minnow larvae for acute toxicity testing.The Biomonitoring Laboratory conducts toxicity test for use in the National Pollutant Discharge Elimination System (NPDES) and the Region 6 TOXNET program to identify effluents, receiving waters, ambient waters and sediments containing toxic materials in acute or chronic toxic concentration. Acute and chronic refer to the length of time organisms are exposed to toxicants before adverse responses are observed.

The Biomonitoring Laboratory maintains both marine and freshwater vertebrate and invertebrate brood stock from which test organisms are obtained . The majority of tests conducted by the Houston Biomonitoring Laboratory is for vertebrate and invertebrate chronic testing.

Picture of biologist examining test cultures for possible mortality.    Invertebrate freshwater tests are conducted on young less than twenty four hours old. One juvenile is added to each of ten replicates for the control culture water and to each concentration of test solution. Test chambers are 30 ml beakers containing 15 ml of test or control water. The organisms are fed daily. Mortality and number of young produced is monitored daily. After seven days, the tests are terminated. Mortality and reproduction data are then analyzed statistically to determine differences between control organisms and those exposed to the test solutions.

Picture of biologist examining cerioduphnia  dubia for acute toxicity testing.Vertebrates (freshwater and marine) fish embryos less than thirty six hours old are used to initiate the tests. Ten embryos are added to each of three replicated for the control culture water and each concentration of test solution. Test chambers are 400 ml Nalgene culture dishes containing 250 ml of test ml of test or control water. Larvae generally hatch on day five of the seven day test. Mortality, dissolved oxygen, and temperature is recorded daily. At the termination of the test, mortality and growth (weight) are analyzed statistically to determine differences between control organisms and those exposed to the test solutions. The Biomonitoring Laborarory is part of the Laboratory Support Team , under the direction of the Associate Branch Chief.

 

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