IVL har pa uppdrag av Naturvardsverket genomfort en screening av sotningsmedlet sukralos. Sukralos ar en disackarid, som modifierats i tre positioner med klor. Amnet ar ca 600 ganger sotare an sack ...

Summary IVL has performed a "screening study" of sucralose on commission from the Swedish EPA. Sucralose is a chlorine containing derivative of sucrose, manufactured by selectively substituting three hydroxyls with chlorine. The substance is used as a sweetener in food products; on a weight basis it tastes ca. 600 times sweeter than the parent compound. The objectives of the study were to determine the concentrations of sucralose in media in the Swedish environment related to wastewater effluents and to highlight important transport pathways. In total 57 samples were analysed representing wastewater and sludge from sewage treatment plants as well as surface waters.

Summary Amines are important chemicals that are being used in a vast number of chemical processes. As an assignment from the Swedish Environmental Protection Agency, a screening study of a selected number of amines has been performed. The overall objective of the screening was to determine the concentrations of amines in a variety of media in the Swedish environment.

Juvenile zebrafish (Danio rerio) were exposed to different dilutions (0, 0.67, 2.5, 10, and 50%) of effluent water from a Swedish pulp mill that previously has been reported to be androgenic to fish. Exposure was performed between days 10–38 days post-hatch. Fish were sampled for whole-body vitellogenin concentrations at day 38 post-hatch and for histological examination of gonads at day 60 post-hatch. In fish exposed to the highest concentration of pulp mill effluent, elevated concentrations of vitellogenin were measured. The androgenicity of the pulp mill water was confirmed by the increased number of males recorded at 60 days post-hatch. Image analysis of testes indicated stimulation of spennato genesis. Intersex fish were observed in all exposure groups. An androgenic activity equivalent to 5.6 ng/L dihydroxytestosterone was measured using the yeast androgen screen (YAS) assay. The present study demonstrates that both androgenic and estrogenic effects can be detected when exposing zebrafish during the juvenile period to complex mixtures of chemicals.

Estrogenicity in Swedish wastewaters was surveyed. Estrogenicity was examined using a recombinant yeast cell test and analyses of the yolk protein precursor in the blood of caged juvenile rainbow trout at sites close to wastewater outlets or in continuous flow tanks of undiluted wastewater. Estrogenic effects corresponding to <0.1 to 15 ng estradiol equivalents were found in municipal effluents. In 9 of 12 industrial effluents, estrogenic effects were below the detection limit of the screen test. None of the six effluents from the pulp and paper industry, from a steel works, and from two chemical industries had a detectable estrogenic effect. Two assays were used for analysis of plasma vitellogenin, a heterologous enzyme-linked immunosorbent assay and a homologous radio immunoassay. Exposure to undiluted municipal wastewater resulted in increased levels of vitellogenin in the plasma of juvenile trout. Using the more sensitive RIA test, increased levels of plasma vitellogenin were detected in cage exposure of rainbow trout in municipal effluent receiving waters. Textile industry effluents mixed with domestic wastewater were estrogenic probably due to contributions from the domestic effluent. In some effluents, toxicity may have masked estrogenic effects.

Elemental sulfur occurs naturally in marine and limnic sediments. Elemental sulfur, brought in solution in aqueous media by using organic solvents such as methanol as carrier solvent, was toxic in a bacterial luminescence test, known as the Microtox test. Previously, it has been shown that the toxicity in the luminescence test of whole sediments also was correlated to i.a. elemental sulfur using multivariate statistical analysis. Organic solvent extracts of sediments obtained in receiving waters of effluents from a pulp and paper mill was toxic in the luminescence test, and using a toxicity evaluation procedure, the toxic substance was identified as octameric cyclic sulfur, S-8. The substance dominated the toxicity in extracts of both a contaminated sediment and a sediment from a control area. Since the toxicity in the Microtox test of aqueous solutions of S-8 decreased upon storage, a conversion process of the toxic form was indicated. Acute toxicity of S-8 was not limited to the luminescent bacteria in the Microtox test, but was observed in tests with fish larvae if tested with the transient form of elemental sulfur. Tests of acute toxicity with zebra fish and perch larvae were responsive to elemental sulfur. Probably, the toxic form of elemental sulfur is the single cyclic octamer, that due to low aqueous solubility, binding to particulate sediment material or aggregation is converted into a nontoxic form. Acute toxic effects may occur in sulfur containing sediments of varying,redox potentials or where elemental sulfur deposits are turbated. (C) 1998 by John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 217-224,1998.

The effluent from deinking of high-yield pulp-based newsprint and tissue production exhibited slight toxicity to bioluminescent bacteria, a green alga and fish. The toxicities are expressed in toxic units (TU) that are in the range of 1.1 to 2. These values are also applicable to chronic toxicity for fish and sublethal effects such as the sensitivity of offsprings from parent fish preexposed for the effluent. The organic content of the effluent was biologically degradable to ca. 70% based on COD and TOC. The biologically stabilised effluent was non-toxic to the organisms assayed. The residual organic matter of the stabilised effluent contained mostly fatty acids in concentrations comparable to those in the raw water used in production. The daily discharge of potentially bioaccumulative organic matter from the production amounted to about 6.2 kg, while the river water from which the raw water is taken and which enters the same recipient as the effluent, transports about 1,700 kg per day.

Single-species laboratory tests were used to assess the acute toxicity of halogenated phenolic compounds. No single test system was most sensitive to all of the compounds examined, substantial variations in the sensitivity of the various organisms were noted, and there was no correlation between the toxicities assayed with different test systems. The zebra fish (Brachydanio rerio) embryo/larvae system was used to examine subacute effects using two of the compounds, and a protocol was developed with 6 weeks preexposure to the toxicant. Preexposure decreased the lowest observable effect concentration by a factor of about 4, and the effect was completely reversible during a 6-week postexposure period in the absence of the toxicant. An enclosed system for carrying out the zebra fish embryo/larvae test was developed and evaluated with three neutral volatile compounds: the median survival time and the frequency of occurrence of deformation were examined as end points. The effect of pH on toxicity was evaluated in buffered media for four of the test systems: toxicity increased markedly at the lower pH values, and it could be shown that the ionized forms of the phenols were not the only contributors to toxicity. It is proposed that the zebra fish system incorporating preexposure could be incorporated into a hierarchical system using a range of organisms for assessing acute toxicity in single species under laboratory conditions and multicomponent systems simulating natural ecosystems.

This paper reports on a set of interacting chemical, biological, and microbiological procedures which can be used to assess the impact of organic chemicals discharged into the aquatic environment. The authors have applied this set of procedures to chloroguaiacols, chlorocatechols, and chlorovanillins-components of bleachery effluents. In this analysis, biodegradation is distinguished from biotransformation. Metabolic transformations may result in the synthesis of compounds not necessarily less toxic nor more readily degradable than their precursors. Anaerobic microbial reactions are important, since substantial amounts of chlorophenolic compounds can be recovered from contaminated anaerobic sediments. These compounds can become bound to natural matrices-particularly sediments-but there are inherent problems on the bioavailability of the compounds. In a valid assessment of environmental hazard, all of these factors should be taken into account.

An account is given of microbial transformations of chloroguaiacols and chlorocatechols. Experiments were carried out with pure cultures of aerobic bacteria and endogenous anaerobic bacteria in contaminated samples of sediment. Particular attention was directed to the role of environmental parameters in determining the fate of compounds discharged into the aquatic environment and to the potentially toxic effects of metabolites. An attempt has been made to assess the environmental significance of the results of laboratory experiments, and the data incorporated into a hypothetical ‘guaiacol cycle'.

AbstractA protocol for determination of “no-effect” concentrations on hatch and survival in the zebrafish (Brachydanio rerio) has been evaluated at five laboratories for variability using chromium (K2Cr2O7) and zinc (ZnSO4 × 7H2O) as toxicants. Repeatability (r) and reproducibility (R), expressed as C.V. (coefficient of variation), for logarithmic median survival time ranged between 1% and 9% for r and between 1% and 29% for R depending upon concentration of toxicant. Variability increased at high concentrations, especially for zinc. For logarithmic median hatching time, C.V. for r ranged from 6% to 24% and for R between 11% and 27% for the various concentrations of chromium and zinc. Estimated logarithmic “no-effect” concentrations on survival of zinc and chromium had a C.V. for r below 10% and a C.V. for R below 15% for zinc and below 25% for chromium. Zinc delayed the time to hatch at lower concentrations than those that reduced survival time, for the estimated logarithmic “no-effect” concentrations of zinc on hatch r was around 75% and R around 100%. The “no-effect” concentrations based on all nine or ten tests from the five laboratories were 15 mg Cr/L and 0.5 mg Zn/L. Because of the cumulative toxicity of chromium in fish the chronic “safe” concentration may be considerably lower, but the “no-effect” concentration of 0.5 mg Zn/L for effects on hatching time is consistent with the chronic “safe” concentration found in other species of fish at the same hardness (100 mg/L expressed as CaCO3).

Short-term screening tests with the zebra fish (Brachydanio rerio) have been developed for predicting the potential of xenobiotics to impair reproductive success in fish. The aim was to find simple and sensitive test parameters and to simulate exposure situations typical for anadromous fish species (salmonids), which generally cross heavily polluted coastal areas or estuaries before they reach uncontaminated upstream spawning areas. Therefore, particular attention was directed to tests designed to assess adverse effects induced during gametogenesis in adult fish. The test protocol involves exposure of adults prior to, but not during, spawning and the effects are measured in the offspring as alterations in hatching frequency and hatching rate of eggs, and survival and stress tolerance of embryos and larvae. Some representative examples of the application of these tests are given, and it is shown that impairment of reproductive success can be induced by exposure of parent fish prior to spawning at concentrations of xenobiotics at least five times lower than those yielding effects during direct exposure of embryos and larvae. It is suggested that, in hazard assessment programs, tests of the effect of xenobiotics on the offspring of preexposed adults be routinely incorporated.

We have demonstrated that strains of bacteria belonging to the genera Pseudomonas and Acinetobacter possessed the ability to transform, by O-methylation, components of spent bleachery effluent such as 4,5,6-trichloroguaiacol and high molecular weight chlorinated lignin. O-Methylation could be enhanced by the presence of a cosubstrate such as succinate or 4-hydroxybenzoate. We have used zebra fish (Brachydanio rerio) to examine bioconcentration potential, toxicity to embryos and larvae, and the sensitivity of the offspring of exposed adults. Bioconcentration factors (total wet weight) on a logarithmic scale were 3.5 and 4.4 for 3,4,5-trichloroveratrole and tetrachloroveratrole, respectively. The potential for bioconcentration of the other neutral metabolites was inferred from estimated values of the octanol–water partition coefficients. 3,4,5-Trichloroveratrole, tetrachloroveratrole, pentachloroanisole, and 1,2,3-trichloro-4,5,6-trimethoxybenzene had threshold toxic concentrations to zebra fish embryos and larvae of 450, 100, 2.8, and 450 μg∙L−1, respectively, and all of them were capable of inducing, at somewhat lower concentrations, various deformations including curvature of the larvae and distortion of the notochord. Experiments on the effect of preexposure of adults to tetrachloroveratrole at a concentration of 16 μg∙L−1 showed that the offspring were adversely affected, e.g. in a decreased viability of the embryos, lowered median survival time for larvae, and greater sensitivity to tetrachloroveratrole. Both 3,4,5-trichloroveratrole (5–150 μg∙kg liver fat−1) and tetrachloroveratrole (40–400 μg∙kg liver fat−1) were detected in fish from localities subjected to discharge of bleachery effluent, and were absent in fish from uncontaminated localities. Identification of these compounds was based on gas chromatographic, and for tetrachloroveratrole, mass spectrometric, comparison with authentic compounds. We conclude that not only compounds present in bleachery effluent, but those that may be produced in the environment by bacterial O-methylation, have potentially hazardous biological activities. These results shed fresh light on a hitherto neglected aspect of environmental hazard assessment, and we suggest that data for a given compound must be supplemented with that for metabolites that could be produced in the environment.