A comparative study of the toxicity of 1,1,2-trichloroethane,dieldrin, pentachlorophenol and 3,4 dichloroaniline for marine and fresh water organisms

The aquatic toxicity of 1,1,2-trichloroethane, dieldrin, pentachlorophenol and 3,4-dichloroaniline was determined for about 15 marine and fresh water animals and several unicellular algae. Acute, subchronic and chronic tests including reproduction studies, were carried out. The results are summarized in five tables.     

Effects of fluoride on soil fauna mediated litter decomposition

To evaluate the effect of potentially toxic compounds on soil fauna mediated carbon and other mineral fluxes in poplar litter, a terrestrial micro-ecosystem (MES) was developed, with the isopod Porcellio scaber as a representative soil fauna species. An experiment was conducted, in which MES with isopods were compared to MES without isopods. Potassium fluoride was used as a model compound. The isopods influenced the microbial respiration negatively. No effect was found for the isopods on the nitrogen and phosphorus mineralization. After the first four weeks of the experiment the total respiration of the MES was increased and the phosphate concentration decreased at the highest fluoride concentration. After nine weeks, fluoride decreased ammonium, nitrate and phosphate concentrations in the litter. It is concluded that nitrogen and phosphorus mineralization in the MES are more sensitive to effects of fluoride that microbial respiration. The no observed effect concentrations for net mineralization of ammonium, nitrate and phosphorus were, respectively, 17, 5.3 and 53 micromol fluoride per gram dry weight of litter. Fluoride seems to be toxic for microbial processes at concentrations found in moderately polluted areas.     

A guideline supplement for determining the aquatic toxicity of poorly water-soluble complex mixtures using water-accommodated fractions

Regulatory guideline methods for aquatic toxicity testing have generally been developed for pure chemicals tested at concentrations below the limit of their water solubility where exposure concentration can be quantified in terms of a concentration in solution. The same methods may also be applied to testing products which are complex chemical mixtures at product: water ratios that do not exceed the water-solubility of any of the product components. A different approach is required for testing complex mixtures at ratios which exceed water-solubilities of some of the components.     

Ecotoxicological testing in relation to the prior consultation procedure

The methods for testing the toxicity of wastes to be dumped in the sea to marine organisms are reviewed in the light of the requirements of the Oslo Convention. The difficulties in the use of the terms “trace contaminants”, “non toxic”, “harmless” and “rapidly” are discussed.