Aquatic environments

A substantial volume of information has been reviewed for the environmental effects assessment. 

Much of this is in the public domain, but various additional unpublished information has been supplied by industry. For the purposes of the environmental effects assessment, the focus is on the freshwater environment. 

Data on the toxicity of the various organotin species to aquatic organisms are summarized in Table 23. 

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R53 may cause long-term adverse effects in the aquatic environment c... 

Aquatic Toxicity. The standard tests to measure the effect of substances on the aquatic environment are designed to deal with those that are reasonably soluble ia water. Unfortunately this is a disadvantage for the primary phthalates because they have a very low water solubiUty (ca 50 p.g/L) and this can lead to erroneous test results. The most common problem is seen ia toxicity tests on daphnia where the poorly water-soluble substance forms a thin film on the water surface within which the daphnia become entrapped and die. These deaths are clearly not due to the toxicity of the substance but due to unsuitable test design. 

Use of dry chemical, alcohol foam, or carbon dioxide is recommended for cycloahphatic amine fire fighting. Water spray is recommended only to flush spills away to prevent exposures. In the aquatic environment, cyclohexylamine has a high (420 mg/L) toxicity threshold for bacteria (Pseudomonasputida) (68), and is considered biodegradable, that is, rnineralizable to CO2 and H2O, by acclimatized bacteria. 

Because of their hydrophobic nature, siUcones entering the aquatic environment should be significantly absorbed by sediment or migrate to the air—water interface. SiUcones have been measured in the aqueous surface microlayer at two estuarian locations and found to be comparable to levels measured in bulk (505). Volatile surface siloxanes become airborne by evaporation, and higher molecular weight species are dispersed as aerosols. 

Linear alkylbenzenesulfonate showed no deleterious effect on agricultural crops exposed to this material (54,55). Kinetics of biodegradation have been studied in both wastewater treatment systems and natural degradation systems (48,57,58). Studies have concluded that linear alkylbenzenesulfonate does not pose a risk to the environment (50). Linear alkylbenzenesulfonate has a half-life of approximately one day in sewage sludge and natural water sources and a half-life of one to three weeks in soils. Aquatic environmental safety assessment has also shown that the material does not pose a hazard to the aquatic environment (56). 

D. R. E. Hademan, Feport of a Workshop on the Impact of Thermal Power Cooling Systems on Aquatic Environments, CONE-750.980, EPRI SR-38, Asildmar, Pacific Grove, Calif., Sept. 28—Oct. 2, 1975, pp. 128—135. 

P. Pitter and J. Chudoba, Biodegradability of Organic Substances in the Aquatic Environment, CRC Press, Boca Raton, Ela., 1990. 

In several cases, such as shellfish areas and aquatic reserves, the usual water quaUty parameters do not apply because they are nonspecific as to detrimental effects on aquatic life. Eor example, COD is an overall measure of organic content, but it does not differentiate between toxic and nontoxic organics. In these cases, a species diversity index has been employed as related to either free-floating or benthic organisms. The index indicates the overall condition to the aquatic environment. It is related to the number of species in the sample. The higher the species diversity index, the more productive the aquatic system. The species diversity index is computed by the equation K- = (S — 1)/logjg I, where S is the number of species and /the total number of individual organisms counted. 

Environmental. The toxicity of cyanide in the aquatic environment or natural waters is a result of free cyanide, ie, as HCN and CN . These forms, rather than complexed forms such as iron cyanides, determine the lethal toxicity to fish. Complexed cyanides may revert to free cyanide under uv radiation, but the rate is too slow to be a significant toxicity factor. Much work has been done to estabhsh stream and effluent limits for cyanide to avoid harmful effects on aquatic life. Fish are extremely sensitive to cyanide, and the many tests indicate that a free cyanide stream concentration of 0.05 mg/L is acceptable (46), but some species are sensitive to even lower concentrations. 

E. J. Weber, Fate of Textile Dyes in the Aquatic Environment Degradation of Disperse Blue 79 in Anaerobic Sediment-Water Systems, Environmental Research Laboratory, U.S. EPA, Athens, Ga., Mar. 1988. 

M. H. Depledge, in Toxic Impacts of Wastes on the Aquatic Environment, ed. J. F. Tapp, S. M. Flunt... 

The biogeochemical processes that generally describe the interaction of elements with particles are quite well known dissolution, flocculation, ion exchange, sorption, (co)precipitation, electron transfer, and biological uptake. In aquatic environments these reactions often occur simultaneously and competitively. In order to utilize marine tracers effectively, we must understand how elements are associated with particles and sediments. 

As Guardians of the Water Environment , the National Rivers Authority (NRA) has statutory duties and powers to protect the aquatic environment from... 

Until recently, the NRA has not participated during the approval process in assessing the potential environmental impact of pesticides. However, the NRA does supply monitoring data to MAFF and HSE for pesticide reviews. These occur once a pesticide has been approved for use for a certain length of time, or when further information is needed on an approved pesticide. In supplying these data, the NRA comments on any areas of concern. This contributed to the 1993 ban on the use of atrazine and simazine on non-cropped land. In January 1995 the NRA s National Centre for Toxic and Persistent Substances (TAPS) was made advisor to the DoF, on the potential impact on the aquatic environment of... 

Strict control is necessary over pollutant levels, acidity, temperature, turbidity, etc. because of their impact upon aquatic environments. Common pollutants in aqueous effluents are identified in Table 16.11. 

Organohalogenated compounds and substances which may form such compounds in the aquatic environment Organophosphorus compounds Organotin compounds... 

Substances which have a deleterious effect on the taste and/or smell of the products for human consumption derived from the aquatic environment Toxic or persistent organic compounds of silicon Inorganic compounds of phosphorus and elemental phosphorus Non-persistent mineral oils and hydrocarbons of petroleum origin Cyanides, fluorides... 

Tapp, J. et al. (ed.) (1996) Toxic Impact of Wastes on the Aquatic Environment, Royal Society of Chemistry, London. 

Biomass All organic matters including those belonging to the aquatic environment that grow by the photosynthetic conversion of low energy carbon compounds employing solar energy. 

The mechanisms by which Pu(IV) is oxidized in aquatic environments is not entirely clear. At Oak Ridge, laboratory experiments have shown that oxidation occurs when small volumes of unhydrolyzed Pu(IV) species (i.e., Pu(IV) in strong acid solution as a citric acid complex or in 45 percent Na2Coj) are added to large volumes of neutral-to-alkaline solutions(23). In repeated experiments, the ratios of oxidized to reduced species were not reproducible after dilution/hydrolysis, nor did the ratios of the oxidation states come to any equilibrium concentrations after two months of observation. These results indicate that rapid oxidation probably occurs at some step in the hydrolysis of reduced plutonium, but that this oxidation was not experimentally controllable. The subsequent failure of the various experimental solutions to converge to similar high ratios of Pu(V+VI)/Pu(III+IV) demonstrated that the rate of oxidation is extremely slow after Pu(IV) hydrolysis reactions are complete. 

Fukai, R. Yamato, A. Thein, M. and Bilinski, H., "Techniques for Identifying Transuranic Speciation in Aquatic Environments" STI/PUB/613, International Atomic Energy Agency, Vienna, 1981, pp. 37-41. 

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