Line Emilie Sverdrup

Toxicity of eight polycyclic aromatic compounds to red clover (Trifolium pratense), ryegrass (Lolium perenne), and mustard (Sinapsis alba).

The effect of eight polycyclic aromatic compounds (PACs) on the seed emergence and early life-stage growth of three terrestrial plants (Sinapsis alba, Trifolium pratense and Lolium perenne) were studied in a greenhouse, using a Danish agricultural soil with an organic carbon content of 1.6%. After three weeks of exposure, seed emergence and seedling weight (fresh weight and dry weight) were determined. Exposure concentrations were verified with chemical analysis. The substances tested were four polycyclic aromatic hydrocarbons (fluoranthene, pyrene, phenanthrene and fluorene), the N-, S-, and O-substituted analogues of fluorene (carbazole, dibenzothiophene and dibenzofuran, respectively), and the quinoline representative acridine. Seedling growth was a far more sensitive endpoint than seed emergence for all substances. Concentrations estimated to give a 20% reduction of seedling fresh weight (EC20-values) ranged from 36 to 290 mgkg(-1) for carbazole, 43 to 93 mgkg(-1) for dibenzofuran, 37 to 110 mgkg(-1) for dibenzothiophene, 140 to 650 mgkg(-1) for fluoranthene, 55 to 380 mgkg(-1) for fluorene, 37 to 300 mgkg(-1) for phenanthrene, and 49 to 1300 mgkg(-1) for pyrene. For acridine, no toxicity was observed within the concentration range tested (1-1000 mgkg(-1)). As illustrated by the EC20-values, there was a rather large difference in sensitivity between the species, and T. pratense was the most sensitive of the species tested.

Effects of the antibacterial agents tiamulin, olanquindox and metronidazole and the anthelmintic ivermectin on the soil invertebrate species Folsomia fimetaria (Collembola) and Enchytraeus crypticus (Enchytraeidae)

Veterinary pharmaceutical products such as antibacterial agents and antiparasitics are widely used to control diseases and promote production in the agricultural sector. Exposure of non-target organisms are a likely result of using manure from treated live stocks or from dung dropped on the field by grazing animals. The aim of this study was to determine the toxic threshold levels of three antibacterial agents (tiamulin, olanquindox and metronidazole) and one anthelmintic (ivermectin) to two species of soil dwelling organisms (springtails and enchytraeids), that are often found in bio-solids such as manure or dung. The antibacterial agents were not toxic to adults and effects on reproduction occurred generally above concentrations normally found in soil or dung. The threshold values for toxicity (10% reduced reproduction or EC10 values) were in the range of 61-111 mg kg(-1) dry soil for springtails and 83-722 mg kg(-1) dry soil for enchytraeids. Ivermectin was significantly more toxic with EC10 values of 0.26 mg kg(-1) dry soil for the springtails and 14 mg kg(-1) dry soil for the enchytraeids. A comparison of these results with rough estimates of likely and worse case environmental concentrations indicates a potential risk of ivermectin to non-target species such as springtails and enchytraeids, whereas direct toxic effect of antibacterial agents is very unlikely to occur at environmental realistic concentrations. However, indirect effects of antibacterial agents driven through changes in the food web cannot be abolished at this stage.

Environmental risk assessment of acrylamide and methylolacrylamide from a grouting agent used in the tunnel construction of Romeriksporten, Norway.

Increased focus on the possible evironmental risk associated with large-scale use of grouting agents has revealed that leakage of chemicals from grouting activities may cause harm to the environment. Chemical grouting agents are used to reduce water leakages in e.g. tunnel constructions. The present study focuses on monitoring results and environmental risk caused by releases of non-polymerised monomers during use of the acrylamide-based grouting agent Rhoca-Gil (Siprogel). Drainage water from the tunnel Romeriksporten was monitored with respect to acrylamide and methylolacrylamide, as leakage of these substances was observed earlier in connection with similar constructions where Rhoca-Gil was used. Concentrations of acrylamide and methylolacrylamide in the draining water showed that these substances leaked out both in connection with the injection of Rhoca-Gil and in connection with after-injection using other grouting agents. Gel formation studies with Rhoca-Gil showed that a low degree of polymerisation (and hence, large leakages of monomers) can be expected if the product is diluted with water. Results from investigation of the environmental fate of methylolacrylamide showed that this substance is chemically transformed at the high-pH conditions of the tunnel. Ecotoxicological testing of the substances and an environmental effects assessment for the receiving water (River Alna and the Oslofjord) showed that the discharge of acrylamide and methylolacrylamide may have caused effects on the aquatic life in the river and in a limited area of the fjord.

Recovery of cholinesterase activity in the earthworm Eisenia fetida Savigny following exposure to chlorpyrifos

Organophosphorus (OP) insecticides inhibit cholinesterase activity, an essential process in the nervous system of most animals. Re-establishment of active enzymes is slow and depends on elimination of the insecticide from the body followed by two lengthy processes: Reactivation and/or biosynthesis of new enzymes. Earthworms (Eisenia fetida) were exposed to either clean or chlorpyrifos-containing (240 mg/kg) soil for 48 h. After transfer to clean soil, we monitored two cholinesterases (E1 and E2) and chlorpyrifos content of the earthworms for 12 weeks. After 14 to 21 d of recovery, the exposed and control worms were indistinguishable in terms of appearance and behavior. Chemical analysis showed a rapid elimination of chlorpyrifos from the earthworms, with only minor levels detected after one week. The activities of E1 and E2 were measured spectrophotometrically in whole specimen homogenates using acetylthiocholine as the substrate. Carbaryl, which selectively inhibits E1, was used to discriminate the enzyme activities. Mean +/- standard error of mean of E1 and E2 activity in the controls immediately after exposure were 1.57 +/- 0.18 nanokatal (nkat)/mg protein (n = 3) and 0.95 +/- 0.07 nkat/mg protein, respectively, and 0.48 +/- 0.07 nkat/mg and 0.45 +/- 0.06 nkat/mg, respectively, in exposed worms. After three weeks, E1 had regained an activity comparable to the controls, whereas E2 remained depressed throughout the 12-week monitoring period. The non- or late recovery of E2 makes this enzyme a potential biomarker candidate for previous OP insecticide exposure in Eisenia fetida, provided the protocol for measurements is improved and standardized.

Relative sensitivity of one freshwater and two marine acute toxicity tests as determined by testing 30 offshore E & P chemicals

Acute toxicity of 30 offshore E & P (Exploration and Production) chemicals was measured using the three standard test organisms Daphnia magna (freshwater cladoceran), Acartia tonsa (marine copepod) and Skeletonema costatum (marine diatom alga). Test chemicals included 20 water-soluble and 10 (partially) non-soluble products. For 22 out of the 30 chemicals, the difference in sensitivity between the three tests varied within one order of magnitude. A very good correlation was found between the two marine tests (r = 0.96, P < 0.01, n = 30), and a correlation coefficient of r = 0.78 (P < 0.01, n = 30) was found between D. magna and both A. tonsa and S. costatum, individually. When the comparison of D. magna and A. tonsa sensitivity was based only on the water-soluble chemicals, a significantly higher correlation was obtained (r = 0.84, n = 20), indicating that the sample preparation method used for the (partially) non-soluble chemicals (the water accommodated fraction (WAF) method) induces additional variation between tests performed with different test media. (Partially) non-soluble chemicals are characterised by phase separation or precipitation at the concentrations used for testing. In a WAF-based test, each test concentration/exposure level is prepared separately, and following mixing and separation, only the water phase is used for testing. Toxicity is related to the amount of substance originally added to the mixing vessels. For 25 of the 30 chemicals, D. magna was found to be less sensitive than the marine copepod by a factor >2. The generally higher sensitivity of the marine toxicity tests compared to the Daphnia test emphasise the importance of using marine data for environmental hazard classification as well as for environmental risk assessment purposes.

Comparative toxicity of acrylic acid to marine and freshwater microalgae and the significance for environmental effects assessments

In this study, we compared the sensitivity of freshwater and marine organisms to two structurally similar substances, acrylic acid and methacrylic acid. Reported acute toxicity data (L(E)C50-values) for freshwater organisms range from 0.1 to 222 mg/l and 85 to >130 mg/l for acrylic acid and methacrylic acid, respectively. The large variation in toxicity data for acrylic acid is due to a specific toxicity to certain species of freshwater microalgae, with algae EC50-values being two to three orders of magnitude lower than L(E)C50-values reported for fish and invertebrates. To evaluate the sensitivity of marine organisms, ecotoxicity data was generated for ten species of microalgae, one invertebrate species and one fish species. For methacrylic acid, we found a marine acute toxicity that ranged from 110 to >1260 mg/l, which is comparable to reported data on freshwater organisms. In strong contrast, the resulting L(E)C50-values for acrylic acid ranged from 50 to >1000 mg/l, and there was no specific sensitivity of marine algae when compared to marine invertebrates and fish. For acrylic acid, therefore, use of the available freshwater toxicity data for an effects assessment for the marine environment is likely to overestimate the hazard and risk from this substance. Overall, the results of the study suggest that ecotoxicity data generated on freshwater species may not always be appropriate for the effects assessments of organic chemicals in the marine environment, thus emphasising the importance of using ecologically relevant data to assess environmental risk.

Polycyclic aromatic hydrocarbon ecotoxicity data for developing soil quality criteria.

With the overall perspective of calculating soil quality criteria (SQC) for the group of polycyclic aromatic hydrocarbons (PAHs), the existing ecotoxicity data for the soil compartment have been reviewed. The majority of data useful in the context of deriving SQC are of recent origin. Soil quality criteria are considered valuable tools for assessing the environmental risk of contamination, as they may give guidance on concentration limits for various chemicals to protect the function and structure of ecosystems. Soil quality criteria for soil-dwelling species were calculated using various assumptions and two internationally accepted methods, i.e., application of assessment factors and species sensitivity distributions, respectively. It was suggested to derive ecotoxicological soil quality criteria, which focus on the lower molecular weight PAHs, i.e., those with log Kow values lower than 5.5 or 6; this is the log Kow range where a cutoff in toxicity for terrestrial species is expected for narcotic substances. Predicted values from the two methods were similar. Calculations showed that, for four individual PAHs of three or four rings, SQC fall in the range of 1.0 and 2.5 mg kg(-1). However, as no individual PAH is fond alone it is suggested to use a sum criterion for a group of PAHs instead. The different possibilities to calculate such a sum criterion are discussed. Based on toxicity data presented here and the average abundance of different PAHs in nearly 1000 Danish soil samples, an ecotoxicological soil quality criterion of 25 mg kg(-1) dry weight for the sum of the eight PAHs acenaphthene, fluorene, anthracene, phenanthrene, pyrene, fluoranthene, benz[a]anthracene, and chrysene is suggested.

Effects and uptake of polycyclic aromatic compounds in snails (Helix aspersa)

The International Standardization Organization recently launched a soil toxicity test with snails (Helix aspersa). We assessed the sensitivity of this test for seven polycyclic aromatic compounds. Control animals had 100% survival and low variability for growth measurements. Maximum exposure concentrations of 2800 mg/kg (4000 mg/kg for acridine) had no effect on survival. Similarly, growth (biomass and shell size) was not affected by pyrene, fluoranthene, fluorene, carbazole, phenanthrene, or acridine, whereas dibenzothiophene gave a 10% effect concentration of 1600 mg/kg. Measured internal concentrations of carbazole, dibenzothiophene, and acridine increased with increasing soil concentrations, but biota-soil accumulation factors were low (0.002-0.1). Compared to previously tested organisms, with all being exposed in the same soil type and under similar test conditions, the H. aspersa test was relatively insensitive to all substances.