Sediments environmental fate

Methyltins are less likely than the butyl- and octyl-tins to partition to sediments, soils, and organic carbon. Modelled data for K c suggest much lower capacity for binding to organic carbon than do measured values, often by several orders of magnitude. Measured data have been used in preference to model environmental fate of the compounds. The compounds also bind strongly to clay minerals, montmorillonite in particular. 

Environmental Fate. Endosulfan partitions to the atmosphere and soils and sediments. It is transported in the atmosphere (Gregor and Gummer 1989 Strachan et al. 1980), but it is immobile in soils (Bowman et al. 1965 El Beit et al. 1981c Hodapp and Winterlin 1989 Stewart and Cairns 1974). 

In Chapter 3, the distribution of enviromnental chemicals through compartments of the gross environment was related to the chemical factors and processes involved, and models for describing or predicting environmental fate were considered. In the early sections of the present chapter, the discnssion moves on to the more complex question of movement and distribntion in the living environment— within individuals, communities, and ecosystems—where biological as well as physical and chemical factors come into play. The movement of chemicals along food chains and the fate of chemicals in the complex communities of sediments and soils are basic issues here. 

An appropriate mineral medium supplemented with the organic compound that is to be studied is inoculated with a sample of water, soil, or sediment. In studies of the environmental fate of a xenobiotic in a specific ecosystem, samples are generally taken from the area putatively contaminated with the given compound so that a degree of environmental relevance is automatically incorporated. Attention has, in addition been directed to pristine environments, and the issues of adaptation or preexposure have already been discussed. 

Saski EK, A Vahatalo, K Salonen, MS Salkinoja-Salonen (1996b) Mesocosm simulation on sediment formation indnced by biologically treated bleached kraft pulp mill wastewater in freshwater recipients. In Environmental Fate and Effects of Pulp and Paper Mill Effluents (Eds MR Servos, KR Munlittrick, JH Carey, and GJ van der Kraak), pp. 261-270. St Lucie Press, Delray Beach, FL. 

Environmental fate Persistence - P Soil or sediment >1 80 Soil, sediment >50 to Soil, sediment 30 to Soil, sediment <30 days... 

Adams WJ, Ziegenfuss PS, Renaudette WJ, et al. 1986. Comparison of laboratory and field methods for testing the toxicity of chemicals sorbed to sediments. In Poston TM, Purdy R, eds. Aquatic toxicology and environmental fate, Vol. 9. American Society for Testing and Materials Special Technical Publication 921,494-513. 

Heitkamp MA, Huckins JN, Petty JD, et al. 1984. Fate and metabolism of isopropylphenyl diphenyl phosphate in freshwater sediments. Environmental Science and Technology 18 434-439. 

Environmental Fate. Hydrogen sulfide is known to easily evaporate into the air (EPA 1993 Layton and Cederwall 1986 Leahey and Schroeder 1986), although its solubility in water may also cause it to persist in unperturbed, anoxic sediments. Additional information on the transport, transformation, and persistence of the compound in soils and groundwater, particularly at hazardous waste sites, would be useful in identifying the most important routes of human exposure to hydrogen sulfide. 

Such simulations suggest that because of their relatively high water solubility which in combination with low vapor pressure causes low air-water partition coefficients, the phenols tend to remain in water or in soil and show little tendency to evaporate. Their environmental fate tends to be dominated by reaction in soil and water, and for the more sorptive species, in sediments. Their half-lives are relatively short, because of their susceptibility to degradation. 

Endrin ketone may react with photochemically generated hydroxyl radicals in the atmosphere, with an estimated half-life of 1.5 days (SRC 1995a). Available estimated physical/chemical properties of endrin ketone indicate that this compound will not volatilize from water however, significant bioconcentration in aquatic organisms may occur. In soils and sediments, endrin ketone is predicted to be virtually immobile however, detection of endrin ketone in groundwater and leachate samples at some hazardous waste sites suggests limited mobility of endrin ketone in certain soils (HazDat 1996). No other information could be found in the available literature on the environmental fate of endrin ketone in water, sediment, or soil. 

Both the NP + A9PEOi+2 concentrations in sediment with and without overlying macroalgae and the increased concentrations in resuspended material during the algal bloom showed the important role played by algae in the environmental fate of A9PE0. 

In conclusion, the processes dominating the environmental fate of non-ionic surfactants in estuaries are biodegradation in the water column, sorption/sedimentation and volatilisation, together with the dynamics of the estuary, in particular water residence times. 

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