Pollutants, fish tissue

Klumpp, D.W., Hong, H.S., et al., 2002. Toxic contaminants and their biological effects in coastal waters of Xiamen, China. I. Organic pollutants in mussels and fish tissues. Marine Pollut. Bull. 44, 752-760. 

Interim Methods for the Sampling and Analyses of Priority Pollutants In Sediments and Fish Tissue," U.S. Environmental Protection Agency, 1981. 

BIOACCUMULATION will probably not bioconcentrate in fish predicted to be a little higher in fish tissues than the water the fish was in in microorganisms used to simulate anaerobic conditions, 50% of the pollutant disappeared in 5-6 months... 

The first results of ecotoxicological studies revealed no bioaccumulation of harmful matter in fish tissues. Such data were quite expected, since the samples were collected during May, shortly after pollutants were discharged into the Danube. 

Sediments can be sources of toxicants and are an important consideration in toxicological chemistry. Although heavy metal sulfides such as PbS and CdS are removed from water into sediments, when the sediments are stirred up the sulfides can be oxidized to toxic soluble forms. The dense, toxic pollutants polychlorinated biphenyls (PCBs) have accumulated in Hudson River sediments as discussed in Chapter 4, Section 4.12. As noted in Section 3.11, anoxic bacterial processes in sediments may convert insoluble inorganic mercury to mobile methylmercury compounds that contaminate fish tissue. Bottom-feeding organisms may bioaccumulate metal and organic pollutants that have accumulated in sediments. 

First discovered as environmental pollutants in 1966, polychlorinated biphenyls (PCB compounds) have been found throughout the world in water, sediments, bird tissue, and fish tissue. These compounds constitute an important class of special wastes. They are made by substituting from 1 to 10 Cl atoms onto the biphenyl aryl structure as shown on the left in Figure 4.13. This substitution can produce 209 different compounds (congeners), of which one example is shown on the right in Figure 4.13. 

While the most of metallothionein research has been carried out on mammals or vertebrates, there are only few studies focused on invertebrates. Application of invertebrates as a suitable model for detection and monitoring the metal pollution of the environment has been shown in several works [129-134]. MT was usually determined as a biomarker of contamination of aquatic environment by heavy metals. Connection between increased levels of metallothionein as a biomaiker in different fish tissues and environmental pollution has been published in many papers [73,76,93,135-142]. On the other hand, application of MT as a biomaiker of metal pollution has been shown for the other animal species too [25, 26, 102, 103, 143-152]. 

Fish bioaccmnulation and biomarkers in environmental risk assessment have been reviewed by Oost et al. [360]. Fish bioaccmnulation markers may be applied in order to elucidate the aquatic behavior of enviromnental contaminants and to assess exposme of aquatic organisms. The feasibility of PAH tissue concentrations in marine species as a monitoring parameter for PAH exposme depends on their uptake, biotransformation and excretion rates. Since it remains hard to accmately predict bioaccumulation in marine species, even with highly sophisticated models, analyses of tissue levels are required. The main problem is that PAHs do not tend to accumulate in fish tissues in quantities that reflect the exposme. The analysis of PAH metabolite levels in fish bile can be used to assess the actual PAH uptake, rather than the analysis of the non-hydroxylated PAHs content [328,361]. A number of sentinel fish species have been proposed to asses pollution by PAHs [325,326], as well as several mussels [322,323,326,352]. Several studies have also correlated the high levels of 1-OHPy and B(a)Py metabolites found in the bile of cat-shark with contamination sources such as boat traffic and combustion-based industries present in the sampling area [362]. 

Measurement of contaminants in fish has concentrated on muscle tissue since the aim has generally been to protect the health of the consumer rather than that of the fish. Endocrine tissue such as the gonads has been much more rarely examined, while data for adrenal, thyroid and pituitary levels are virtually non-existent. More data are available for the liver, as a lipid rich tissue and the major site of xenobiotic catabolism, but the concentrations have rarely been related to its capacity to produce vitellogenin or metabolise endogenous hormones. Tissue concentrations of a wide range of chemicals, are at a level which suggests that, either alone or in combination, they will cause significant endocrine disruption in fish in many polluted habitats. 

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