Biota, aquatic, sediment effect

The most obvious impact of sediment-associated pollutants on aquatic biota is direct acute toxicity and there is considerable literature on both laboratory and field effects of toxic substances on marine and freshwater invertebrates (Baker, 1980 Reynoldson, 1987). For example, Warwick (1980) and Wiederholm (1984) observed deformities in chironomid larvae mouthparts at polluted sites of lakes in Canada and Sweden Milbrink (1983) has shown setal deformities in oligochaetes exposed to high sediment mercury levels. Indirect effects resulting from sediment contamination oftenly include changes in benthic invertebrate community structure. For example, Lock et al. (1981) evidenced increased growth of bacterial flora and algal cells on oiled substrates and a consequent stimulation of macroinvertebrates. Chapman et al. (1982) have shown effects of life history alterations (e.g., impairment of reproduction and age selective toxicity) which have been linked to sediment contaminants. ... 

The toxicological or cumulative effect of illicit drugs on the ecosystems has not been studied yet. Moreover, their fate and transport in the environment is to a big extent still unknown. Due to their physical-chemical properties (octanol-water partition coefficient, solubility, etc.) some of them, such as cannabinoids, are likely to bioaccumulate in organisms or concentrate in sediments whereas the rest, much more polar compounds, will tend to stay in aqueous environmental matrices. However, continuous exposure of aquatic organisms to low aquatic concentrations of these substances, some of them still biologically active (e.g., cocaine (CO), morphine (MOR) and MDMA) may cause undesirable effects on the biota. 

The introduction of estrogens and progestogens into the environment is a function of the way several factors are combined. The manufactured quantity and the dosage applied (amount, frequency, and duration) combined with the excretion efficiency of the compound and its metabolites, the capability of adsorption and desorption on soil, and the metabolic decomposition in sewage treatment are examples of necessary factors to assess environmental exposure. In general the fate and effect of a substance in the environment is dependent on the distribution into the different natural systems, such as air, water, and solids (soil, particles, sediment, and biota). Information on the physical and chemical properties (Ku, Kd, and Kim vapor pressure) of a compound may help determine whether it is likely to concentrate in the aquatic, terrestrial, or atmospheric... 

The presence of surfactants and their biodegradation products in different environmental compartments can invoke a negative effect on the biota. The ecotoxicity of surfactants to aquatic life has been summarised in the scientific literature [1—5]. Nevertheless, some information is still lacking in relation to the aquatic toxicity of surfactants, especially knowledge regarding the toxicity of the degradation products, the effect of surfactants on marine species, the ecotoxicity of mixtures of chemical compounds with surfactants, the relationship between toxicity and chemical residue and the effect of surfactant presence in specific environmental compartments (water, particulate matter, pore-water, sediment). 

Polychlorinated biphenyls (PCBs) were manufactured by catalytic chlorination of biphenyl to produce complex mixtures, each containing 60-90 different PCB molecular species or congeners (see Chaps. 1 and 4). In the United States, PCB mixtures were manufactured by Monsanto under the trade name Aroclor and were widely used as dielectric fluids in capacitors and transformers from 1929 to 1978. PCBs are widespread contaminants of aquatic sediments and continue to be a focus of environmental concern because they tend to accumulate in biota and are potentially toxic. The following sections show the most effective bioremediation techniques applied to various PCB contaminated environments ... 

Research on the behavior of Pu and other actinides in aquatic ecosystems of Oak Ridge National Laboratory involves field studies at White Oak Lake, a 10.5-ha impoundment formed by Mahattan Project operations. This final settling basin has received releases from the Laboratory and associated facilities since 1944. Some of the key questions addressed are (a) the partitioning of Pu between the suspended particulate and soluble fractions in the water column, (b) the partitioning of Pu between the bed sediments and overlying water column, (c) the uptake of Pu by biota from these fractions, and (d) food chain transfers and trophic effect on Pu concentrations in biota of the system. 

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