Aquatic environment contamination

The occurrence of PCDE residues in biota shows that PCDEs have potential for bioaccumulation. The same PCDE congeners have been detected in biota compared to sediment from the same study area and elevated levels of PCDEs are detected in aquatic environment contaminated with PCDEs [33] (Fig. 5). Higher chlorinated PCDEs like octaCDEs seem to bioaccumulate, as well, since they have been measured in fish, seals, and birds [33, 57, 113,124] (Figs. 5 and 6). 

Many authors reported poor elimination of antiepileptic drug carbamazepine [6,13,17,49, 54]. Pharmacokinetic data indicate that only 1-2% of carbamazepine is excreted unmetabolized. However, glucuronide conjugates of carbamazepine can presumably be cleaved in the sewage, and thus increase its environmental concentrations [51]. This is confirmed by its high ubiquity in the enviromnent at concentration levels of several hundred nanograms per liter in different surface waters. Due to its recalcitrant nature, it can be used as anthropogeiuc marker for the contamination of aquatic environment. 

Sumpter, J.P. and Johhng, S. (1995). Vitellogenesis as a biomarker for estrogenic contamination of the aquatic environment. Environmental Health Perspectives 103, 173-178. 

Vethaak, A.D., Lahr, J., and Schrap, S.M. et al. (2005). An integrated assessment of estrogenic contamination and biological effects in the aquatic environment of the Netherlands. 

It is well established that important photochemical reactions are mediated by humic material in the aquatic environment (Zepp et al. 1981a,b), and that these are particularly signihcant for hydrophobic contaminants. Partial reductive dechlorination of the persistent insecticide mirex associated with... 

Golet WJ, Haines TA. 2001. Snapping turtles (Chelydra serpentina) as monitors for mercury contamination of aquatic environments. Environ Monit Assess 71 211-220. 

Traina, S. and Laperche, V., Contaminant bioavailability in soils, sediments, and aquatic environments, Proc Natl Acad Sci USA, 96 (7), 3365-3371, 1999. 

Hunter, J.V., Origin of organics from artificial contamination, in Organic Compounds in Aquatic Environments, Faust, S.D. and Hunter, J.V., Eds., Marcel Dekker, New York, 1971, pp. 51-94. 

We illustrate these concepts by applying various fugacity models to PCB behavior in evaluative and real lake environments. The evaluative models are similar to those presented earlier (3, 4). The real model has been developed recently to provide a relatively simple fugacity model for real situations such as an already contaminated lake or river, or in assessing the likely impact of new or changed industrial emissions into aquatic environments. This model is called the Quantitative Water Air Sediment Interactive (or QWASI) fugacity model. Mathematical details are given elsewhere (15). 

Sites near industrial areas in the Ebro have been found to have the highest concentration of priority contaminants [15, 47—49], while dispersion of agricultural products by drift, runoff and drainage has resulted in residues being found in ground-waters, rivers, coastal waters and lakes far from point sources [50]. Priority contaminants in aquatic environments include persistent organic pollutants (POPs) such as dichlorodiphenylethylenes (DDT) and polybrominated diphenyl ethers (PBDEs). 

Sediments are important compartments for many organic contaminants in the aquatic environment, in particular for hydrophobic POPs such as PAHs and PCBs. Sediments have been recognised as important sinks for these compounds but with the reduction in levels of them in water, the question arises of whether the older highly contaminated sediments will function in the future as secondary sources of the compounds or whether burial by recent, cleaner sediment will prevent exchange with the water phase. This will depend on the strength of turbulence/bioturbation and on anthropogenic influences such as dredging. 

In aquatic environments where point sources of industrial contamination have been identified, the elimination of mercury discharges has usually improved environmental quality. Such improvement has been reported for Minamata Bay (Table 5.4) for sediments in Saguenay Fjord, Quebec,... 

Hothem, R.L. and D. Welsh. 1994. Contaminants in eggs of aquatic birds from the grasslands of central California. Arch. Environ. Contamin. Toxicol. 27 180-185. 

Zwiener C. and Frimmel F., 2004. LC-MS analysis in the aquatic environment and in water treatment-a critical review. Par II Applications for emerging contaminants and related pollutants, microorganisms and humic aicd. Anal Bioanal Chem 378 862. 

Allan, R. J. (1994). Transport and Fate of Persistent Toxic Organic Chemicals in Aquatic Ecosystems the Niagara River to St. Lawrence River Estuary Example. In Hydrological, Chemical a. Biological Processes of Transformation a. Transport of Contaminants in Aquatic Environments, Proc. of the Rostov-on-Don symposium. May 1993, IAHS Publication, 219, pp. 21-32. 

---