Pore waters, sediment

Toxicity in estuarine sediments—use of Mutatox and Microtox to evalu- 173 ate the acute toxicity and genotoxicity of organic sediments Toxicity tests for the analysis of pore water sediment a comparison of 4 174... 

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). 

It is important to note two things in this analysis first, the reactions which govern silicate phase equilibria occur in a system closed to large-scale chemical migration. This corresponds to a pore-water sediment system of local equilibrium. Second, the most striking mineralogical change—the crystallization of feldspar—is, in fact, the result of the instability of another phase, montmorillonite. The use of... 

Morse J.W. and Mucci A. (1984) Composition of carbonate overgrowths produced on calcite crystals in Bahamian pore waters. Sediment. Geol. 40, 287-291. 

Aller, R.C. (1978) Experimental studies of changes produced by deposit-feeders on pore water, sediment and overlying water chemistry. Am. J. Sci. 278, 1185-1234. 

The aquatic sampling and surveillance campaign was conducted over four weeks using five naval vessels. Gamma spectrometric surveys were made of the sea bed in order to optimise sampling. Over 300 samples were collected (from lagoon water, ocean water, sediment pore water, sediment, corals and biota). Some 13 000 litres of water and 1 tonne of solid samples were collected, processed, packaged and transported to Monaco for distribution to analytical laboratories. 

Important for understanding factors controlling the biogeochemical cycle of PCBs In the environment more specifically aquatic ecosystems Including estuaries. Our data have demonstrated this for the case of a severely polluted coastal estuarine area, both for the data discussed herein and for pore water, sediment and water column data presented and discussed elsewhere (10, 30). 

Hesse, R. (1990) Early diagenetic pore water/sediment interactions modem offshore basins. In Diagenesis (Eds Macllreath, I.A. Morrow, D.W.). Geosci. Can. Reprint Series 4, 277-316. 

Fig. 3.25 Inverse relationship between carbon content of sediments (normalized to grain surface area) and exposure time to oxygen (after Gelinas et al. 2001). Oxygen exposure time (OET) = (depth of 02 penetration in sediment pore waters)/(sediment accumulation rate). Ctotaloiganic (mgm 2) = —0.161ogeOET + 1.28 and Cnoll protein (nignE2) = -0.0431ogeOET + 0.32 (r2 = 0.96 for both OET measured in years). Low OETs are typical of coastal sediments and high OETs of deep-sea sediments.

For environmental testing, bioassays provide an integrated picture of the overall toxicity of pore water, sediment elutriate or sediment from a contaminated site. Various aquatic organisms, such as vertebrates, invertebrates, protozoa, algae, macrophytes and bacteria are used to test environmental samples. The idea behind these toxicity tests is that the test organisms will react in a predictable way to various types of environmental contaminants. 

Sediment contact tests are biological methods for the determination of toxic effects induced by whole sediments in direct contact with test organisms, taking into account all possible pathways of contaminant uptake (particle contact, food, pore water). Sediment contact tests are highly relevant in order for an ecosystem approach to consider the actual bioavailability of contaminants sufficiently. 

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