Toxicological Chemistry and Water Pollution

Aquatic organisms may be affected directly by water pollutants. One important example is the feminization of some organisms by exposure to estrogenic pollutants. Mussels and other sedimentdwelling organisms in the hydrosphere have been adversely affected by organotin water pollutants. 

Another important aspect of the toxicological chemistry of water pollutants involves biotransformations and biodegradation of pollutants. Some of the compounds found as markers of water 

Microorganisms in water and sediments can act to detoxify organic water pollutants. As noted in Section 3.14, this most commonly takes place through the process of co-metabolism. In most favorable cases, the pollutants are completely mineralized to inorganic forms. As discussed in Section 3.9, an indirect pathway to detoxification of toxic heavy metal ions occurs when reducing conditions in the bottom regions and sediments in bodies of water convert sulfate ion, SO , to H2S, which precipitates heavy metals as biologically less available metal sulfides. 

Which of the following statements is true regarding chromium in water (a) chromium(III) is suspected of being carcinogenic (b) chromium(III) is less likely to be found in a soluble form than chromium(VI) (c) the toxicity of chromium(III) in electroplating wastewaters is decreased by oxidation to chromium(VI) (d) chromium is not an essential trace element  

What do mercury and arsenic have in common in regard to their interactions with bacteria in sediments  

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