F. Korte

Prediction of ecotoxicological behaviour of chemicals: Relationship between physico-chemical properties and bioaccumulation of organic chemicals in the mussel Mytilus edulis

Abstract The analysis presented in this paper shows that water solubility as well as the n-octanol/water partition coefficient are useful indicators of the tendency of organic chemicals to bioaccumulate. It is suggested that these physico-chemical data be used as screening test for organic chemical bioaccumulation in aquatic organisms, such as the mussel Mytilus edulis .

Polychlorinated biphenyls (PCBs) in the marine environment, particularly in the Mediterranean

Polychlorinated biphenyls (PCBs) possess a low water solubility, a high n-octanol/water partition coefficient, and a high persistence, particularly those which are highly chlorinated. Because of these properties they are bioaccumulated in many organisms in the environment. PCBs are still manufactured industrially and used in the Mediterranean countries (e.g., Italy, Spain, and France). Production figures for these countries and for the FRG, the United Kingdom, and the United States between 1973 and 1979 are given. The concentrations of PCBs in marine air, water, sediments, microplankton , algae, mussels, fish, and other marine organisms including seabirds from the Mediterranean area are reviewed and compared with PCB concentrations in marine samples from non-Mediterranean regions. Levels of PCBs in seawater are highest in the western and central Mediterranean. The data for mussels and fish give a clear indication that the PCB levels are higher in the Northwest and the Tyrrhenian Sea than in the eastern Mediterranean. The FDA in June 1979 set 2 mg/kg as the temporary maximum concentration for PCBs in fish and shellfish. The PCB residues in some fish from the northwestern Mediterranean and Tyrrhenian Sea and in some mussels from the Adriatic Sea are higher than this limit. The amount of PCBs ingested via food by the Mediterranean population is unknown.

QSAR for organic chemical bioconcentration in Daphnia, algae, and mussels.

Prediction of the bioconcentration of organic chemicals from water by aquatic organisms has important applications in the management of hazardous chemicals. This study gives a compilation of bioconcentration factors on a wet weight basis (BCFw) of 52 organic chemicals by Daphnia magna from aqueous solution. The bioconcentration factors for the chemicals in Daphnia were successfully correlated with their n-octanol/water partition coefficients (log Kow) using a linear regression analysis. In addition to the ordinary least-square regression technique, the geometric mean regression technique is also used because this takes into account deviations in Kow values. Both results show that the Kow value of a chemical is a good predictor of the BCF in Daphnia. The BCF-Kow relationships between Daphnia, algae (Chlorella), and mussels (Mytilus edulis) are compared with each other.

Correlation between acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and total body fat content in mammals

Single oral 30-day LD50s of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were correlated with total body fat (TBF) content in various species and strains of laboratory mammals. LD50 values and TBF contents were either obtained from the literature or determined by experiments. A log (LD50) vs. log (TBF) plot yielded a highly significant linear regression equation (r2 = 0.834, P less than 0.001, n = 20). It is suggested that this correlation exists for at least two reasons: (1) increasing TBF content in organisms represents an enhanced capacity to remove TCDD from the systemic circulation and (2) different TBF content reflects a differential role and regulation of fat metabolism for various organisms. Extrapolation of this correlation to man suggests that adult humans are among the less sensitive species to the acute toxicity of TCDD.

Relationship between water solubility of organic chemicals and their bioaccumulation by the alga Chlorella

This paper reports the bioaccumulation of 34 organic chemicals in and on the green alga Chlorella fusca and their relationship to water solubility.

Release characteristics of herbicides from Ca alginate gel formulations

Abstract The usefulness of Ca alginates as matrix material for controlled release formulations was investigated with the herbicides monolinuron (1), desmetryn (2), chloridazon (3), atrazine (4), MCPB (5), simazine (6) and chloroxuron (7) as active ingredients. Release rates of these substances were measured from hydrated and dried gel beads. The results obtained indicate that release from both gel types corresponds to the water solubilities of the active ingredients. Sufficient retardation of herbicide release up to several months could be attained with the hydrated and dried Ca alginate formulations of 6 and 7 (water solubilities 5 and 3.7 ppm, respectively) and the dried formulations of 4 and 5 (water solubilities 70 and 44 ppm, respectively).

Photoinduzierte hydroxylierungsreaktionen organischer chemikalien in natürlichen Gewässern - Nitrate als potentielle OH-radikalquellen -

Abstract Organic chemicals are concentrated in natural waters, where they undergo complex reactions under the influence of solar radiation and catalyzed by substances such as humic acid as well as nitrate and nitrite salts. Nitrates are present in high concentrations in natural waters (5 – 50 mg/l). The photolysis of the nitrate ion leads to the formation of OH-radicals. In this investigation the steady-state concentration of OH-radicals in different aquatic environments is estimated (∼ 5 · 10 −16 mol/l). It depends on the amount of nitrate dissolved in the water. Under the conditions of this work the half life for a great number of organic chemicals lies in the range 80 – 400 hours (for the reaction with OH-radicals).

Determination of adenine nucleotides in soil by ion-paired reverse-phase high-performance liquid chromatography

Abstract A ion-paired reverse-phase high-pressure liquid chromatographic method using fluorescence detection for the determination of adenine nucleotides in soil has been developed. Dimethylsulfoxide (DMSO) was added to soil to stop biological activity; then, phosphate buffer (pH 11.7) was added for a further dispersion. An aliquot of soil suspension was mixed with an equal volume of nucleotide releasing agent (NRB) and then sonified. The adenylates separated from the mixture by passing through a membrane filter were reacted with chloroacetaldehyde to form their corresponding 1.N 6 -etheno-derivatives. These derivatives were eluted on an ODS (C-18) column with 0.05 M ammonium acetate, 1.0 mM EDTA and 0.2 mM tetrabutylammonium hydrogen sulfate (pH 6.3) mixed with methanol (water phase/methanol 9:1 v/v) as a mobile phase. The minimum detection limits of this analytical method were 0.2, 0.1 and 0.05 μg·g −1 dry soil for ATP, ADP and AMP in soil, respectively. The recoveries of soil samples fortified with 1.0, 2.0 and 5.0 μg·g −1 dry soil of the adenine nucleotides were > 80%.

A simple effective procedure for the determination of adenosine triphosphate in soils

Abstract A simple method for the extraction and determination of adenosine 5′-triphosphate (ATP) in soil is described. ATP was extracted by stirring with dimethyl sulphoxide (DMSO), followed by adding 0.01 M trisodium phosphate (Na 3 PO 4 ) buffer solution for a further dispersion. The ATP content was quantitatively measured by luciferin-luciferase system employing a standard addition technique. The method was most efficient in comparison with 7 other extraction procedures. The recoveries of ATP in spiked soil were found to be approximately 100 %. ATP contents in 16 selected soils were in ranges of 0.76±0.05 – 7.79±0.83 μ g/g (dry weight). A significant correlation between ATP amounts and biomasses in these soils was also observed.

Long-term fate of organochlorine xenobiotics in aquatic ecosystems: Distribution, residual behavior, and metabolism of hexachlorobenzene, pentachloronitrobenzene, and 4-chloroaniline in small experimental ponds

Hexachlorobenzene (HCB), pentachloronitrobenzene (PCNB), and 4-chloroaniline (4-CA) were dosed into the water of small experimental ponds in Southern Germany. The average concentration of the chemicals in the pond water during the application period (4-6 weeks) was about 50 micrograms/liter. Chemical residue concentrations were determined in water, sediment, and flora and fauna species up to 166 weeks after application. The decrease of all chemicals in the water phase follows exponential functions and can be correlated to some extent with the physicochemical properties such as volatility from water and vapor pressure. Although chemically quite different, the residual behavior of the model compounds followed a similar pattern resulting in relatively high initial concentrations in biota and a slow buildup and subsequent decline of concentrations in the sediment. As to some fauna species (backswimmers and libellula larvae) and to sediment (0- to 20-cm layers), even 3 years after application, 14C residues of about 0.1 mg/kg could be found. In all analyzed flora species, however, no more residues could be measured in the new vegetation period after application. The amounts of the chemicals used did not cause detectable symptoms of poisoning over the investigation period. Anisols and azo compounds were found to be conversion products of pentachloronitrobenzene and 4-chloroaniline.