Josef Steber

Properties of hydroxyethane diphosphonate affecting its environmental fate: Degradability, sludge adsorption, mobility in soils, and bioconcentration

Abstract No indication of aerobic or anaerobic biodegradability of HEDP was found. Nevertheless, the abiotic degradability of HEDP, particularly in natural waters under sunlight exposure, yielding acetate and inorganic phosphate excludes its environmental persistence. From adsorption and leaching studies a considerable HEDP elimination by sludge adsorption in sewage treatment plants and a characterization as moderately to little mobile in soils can be deduced. The results of a dynamic bioaccumulation test with fish show that HEDP has a very low bioconcentration potential.

Comparative evaluation ofanaerobic biodegradability of hydrocarbons and fatty derivatives currently used as drilling fluids

The examination of a number of potential and currently used carrier fluids for invert emulsion drilling fluids in the ECETOC screening test revealed clear differences with respect to their easy anaerobic biodegradability. Fatty acid- and alcohol-based ester oils exhibited excellent anaerobic degradation to the gaseous final end products of the methanogenic degradation pathway, methane and carbon dioxide. Mineral oils, dialkyl ethers, alpha-olefins, polyalphaolefins, linear alkylbenzenes and an acetal-derivative were not or only slowly degraded. Although the poor degradation results obtained in the stringent ECETOC screening test may not be regarded as final proof of anaerobic recalcitrance, nevertheless, these results were found to be in line with the present understanding of the structural requirements for anaerobic biodegradability of chemicals. The validity of the conclusions drawn is corroborated by published results on the anaerobic biodegradation behaviour of ester oils, mineral oils and alkylbenzenes in marine sediments.

Properties of aminotris (methylenephosphonate) affecting its environmental fate: Degradability, sludge adsorption, mobility in soils, and bioconcentration

Abstract In spite of its low aerobic and anaerobic biodegradability ATMP was shown to be quantitatively decomposed in a number of natural and synthetic waters. The primary products formed are iminodi (methylenephosphonate) (IDMP) and the biodegradable hydroxymethylenephosphonate (HMP). Furthermore, IDMP is abiotically degraded yielding HMP and aminomethylenephosphonate (AMP). The latter was shown to be biodegradable under certain environmental conditions. A degradation mechanism similar to that of ATMP was indicated for ethylenediaminetetra (methylenephosphonate) (EDTMP). ATMP was characterized by adsorption studies as having moderate to low mobility in soils. A very low bioconcentration potential of ATMP was demonstrated in a dynamic bioaccumulation fish test.

The time-window: an inadequate criterion for the ready biodegradability assessment of technical surfactants

The attainment of the biodegradation pass-level within a distinct time period (10 days after the end of the lag-phase) is one of the criteria for assessing the ready biodegradability of chemical substances. The time-window as a simple approach for describing biodegradation kinetics is a poor descriptor in the case of mixtures and poorly soluble compounds. Technically used surfactants are a mixture of numerous homologues and isomers and many are composed of two organic moieties which will be degraded sequentially. The associated problems in fulfilling the time-window requirement and the inadequacy of this criterion for the ready biodegradability assessment of surfactants are illustrated and discussed.

The 'two-phase closed bottle test' : A suitable method for the determination of 'ready biodegradability' of poorly soluble compounds

The Two-Phase Closed Bottle test (BODIS test) is a cost-effective supplement of the existing OECD tests for ready biodegradability (OECD 301) due to its entire compatibility with them and its particular suitability for testing poorly soluble compounds. The comparison of a number of test data from this and other ready biodegradability tests showed that the BODIS test has a similar stringency in terms of the attainment of the pass level and the time window criterion as well. A significant influence of the strength of the bacterial inoculum on the test results was not observed.

Assessment of bioconcentration and secondary poisoning of surfactants

The relevance of the bioconcentration behaviour of surfactants for the secondary poisoning assessment and for the risk characterisation in the bird and mammalian food chain has been investigated. The approach used is described in the recently revised EU Technical Guidance Document for the Risk Assessment of Substances. The results demonstrate that, based on experimentally derived bioconcentration factors, environmental concentrations and effects in animals, there is a clear level of safety for both linear alkylbenzene sulphonate (LAS) and alcohol ethoxylates (AE), the most important surfactants by volume. To assess other surfactants used in detergents, a bioconcentration factor that would need to be attained for secondary poisoning to be of concern has been estimated from predicted environmental concentrations and known long-term effects data in animals. Based on the known structural similarity of these surfactants to LAS and AE and the ubiquitous nature of the enzymatic systems that are present in biotransformation processes in organisms, it is concluded that bioconcentration of these surfactants to these levels is highly unlikely. Therefore the potential for secondary poisoning effects of these surfactants is extremely low.

Prevention of nitrification-caused erroneous biodegradability data in the Closed Bottle Test

Abstract Comparative studies showed that a reduction of the ammonium concentration of the test medium is sufficient to prevent a nitrification-caused oxygen consumption in the Closed Bottle Test when testing nitrogen-free compounds. In case of N-containing test substances a BOD due to nitrification cannot be excluded completely even after substitution of ammonium by nitrate. Analysis of nitrite and nitrate in the final test solutions and correction of the measured BODs for N-oxidation can help to obtain realistic degradation data for N-containing test materials.

3 – The Ecotoxicity of Cleaning Product Ingredients

This chapter discusses the test methods for evaluating the ecotoxicological properties of chemicals and explains how this data can be used for derivation of the (predicted) no-effect concentration (PNEC) as an essential element of the environmental risk assessment process. Subsequently, the ecotoxicological aspects of the most important chemicals used as ingredients in cleaning products are described in more detail. The ecotoxicity of a chemical compound; for example, its toxic impact to the organisms living in an environmental compartment like water, sediment, or soil; is a substance-specific property forming an essential element of the environmental safety assessment too. There is a sensible hierarchy of ecotoxicity tests starting with relatively simple acute toxicity tests allowing a first general evaluation if a substance is to be considered very toxic, toxic, moderately toxic, or poorly toxic to aquatic organisms. The acute tests are followed by more sensitive and more expensive chronic or subchronic tests which have a higher predictive value for the situation normally prevailing in practice. It is the objective of all the tests to establish a dose–response relationship considering the concentration of the test substance and the ecotoxicological effect.