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Current recommended ecotoxicological tests with the parthenogenetic springtail Folsomia candida using standard OECD soil do not allow for continuous monitoring during the exposure period. Effects of chemicals cannot be determined until the end of the experiment (typically after 4 weeks), since the animals stay below the soil surface. In this study, F. candida were maintained on a plaster of Paris/graphite substrate for 7 weeks and were supplied with an aqueous suspension of yeast contaminated with Cd, Cu, Pb, and Zn as nitrate salts. Growth rate, time to first batch of eggs, quantity of food consumed, and the presence of graphite in the gut (a sign of avoidance of yeast) were all affected by metal contaminated diets. The relative toxicities of Cd:Cu:Pb:Zn in the yeast were 1.0:1.07:12.0:4.3, respectively (on a weight basis) with Cd being the most toxic. Internal body concentrations increased, and the concentration factor (metal concentration in F. candida/metal concentration in yeast) decreased with increasing metal exposure. In general, metals are much less toxic when added to the food of F. candida than when incorporated into soil in standard tests. It is suggested that Collembola have a greater tolerance of metals in the diet since they avoid contaminated food, and are able to excrete assimilated metals at moulting via exfoliation of the midgut epithelium where the elements are retained as part of a storage--detoxification system. The methodology described in this article allows effects on growth to be observed as early as 7 days after the beginning of the experiment.

Eisenia fetida was exposed in the laboratory to a range of elevated soil copper (Cu) concentrations under two different contamination histories. An EC10 for reproduction was observed at 34 mg Cu/kg for soil spiked with Cu 1 d prior to running the experiment (newly spiked soil). Soil contaminated with Cu in the field more than 70 years previously (field-contaminated soil) caused a 10% decrease in reproduction at 248 mg Cu/kg. Survival and cocoon wet weights were not affected by soil concentrations up to 1,400 mg Cu/kg under either contamination history. Adult growth was reduced at 428 mg Cu/kg (EC10) in newly spiked soil but not in field-contaminated soil at concentrations up to 1,400 mg Cu/kg. The contamination history, as well as the toxicological parameter, was important in the interpretation of the outcome of a standard laboratory toxicity test. The lysosomal membrane stability of coelomocytes, measured as neutral-red retention time (NRR-time), was reduced at soil Cu concentrations lower than those affecting reproduction and demonstrated a dose–response relationship. The NRR-time was more severely reduced in worms exposed to newly Cu-spiked soil (EC10 = 8 mg Cu/kg) than worms exposed to field-contaminated soil (EC10 = 69 mg Cu/kg). The NRR-time reflected the bioactive Cu fraction, showing a good correlation with reproduction under both contamination histories.

Zinc tolerance in Lumbricus rubellus populations from two metal-polluted (smelter and mine) sites was studied by comparing the effects of zinc with responses in a reference site strain. For the study, adult worms were collected directly from the field. Thus, no attempt was made to differentiate between tolerance resulting from population-level genetic adaptation or phenotypic plasticity in metal physiology. To compare relative sensitivity for zinc, worms from the three populations were exposed in laboratory tests. Effects on survival, weight change, cocoon production, and internal zinc levels were measured. Prior to exposure, it was anticipated that worms from the metal-contaminated sites would show substantially increased tolerance to zinc. This was not the case for all measured parameters. Thus, although differences in the shape of the dose-response relationships for survival and cocoon production were found, substantial variations in measured responses, effect concentrations, or zinc accumulation rates were not apparent. Overall, therefore, zinc tolerance is unlikely to be a major factor influencing the distribution of L. rubellus in contaminated regions.http://link.springer-ny.com/link/service/journals/00244/bibs/37n3p332.html

Exposure of the collembolan Folsomia fimetaria L. to nickel via soil caused significant mortality and reduced growth and reproductive output. Nickel may be present in elevated concentrations due to anthropogenic discharge. Although collembolans are very numerous and important organisms in the soil ecosystem, the effect of nickel has not previously been studied on these organisms. The aim of this study was to investigate the toxic effects of high soil nickel concentrations on the collembolan F. fimetaria following a 3-week exposure in a loamy sand spiked with nickel up to 1000 mg Ni/kg. A 10% decrease in adult female numbers at 427 mg Ni/kg and at 645 mg Ni/kg for adult male numbers was observed for nickel-spiked soil. Juvenile numbers were reduced at 701 mg Ni/kg following a 3-week exposure. The corresponding EC50 values were 786 mg Ni/kg for females, 922 mg Ni/kg for males, and 859 mg Ni/kg for juveniles. The reproductive output seems to be the most sensitive parameter being reduced at soil nickel concentrations above 173 mg Ni/kg (EC10). Adult growth was not affected by soil nickel concentrations up to 1000 mg Ni/kg, but juvenile growth was reduced at concentrations above 480 mg Ni/kg (EC10).

The uptake and excretion kinetics of cadmium, copper, lead and zinc were studied for Eisenia fetida exposed to mixtures of these metals in field and OECD artificial soil. Body burdens in worms exposed to all contaminated soils increased over the duration of the experiment. Highest accumulation rates were for worms exposed to the most polluted soils. Pronounced differences were found in the uptake and excretion patterns for essential and non-essential elements (particularly in field soils). For cadmium and lead (non-essential), an equilibrium plateau was not reached during the uptake study and slow excretion was found on transfer of worms to clean soil. For copper and zinc (essential), fast initial uptake was followed by equilibrium after only a few days exposure. Rapid excretion was found after transfer to clean soil, with half-lives of less than 1 day for both metals. A previous study of the effects of metals on worms exposed in OECD and field soils had indicated a higher toxicity in the artificial medium. Thus, in the present study, it was anticipated that greater toxicity would be reflected by increased body burdens for worms in OECD soil. This was, however, not the case. Explanations are given that might account for the fact that the greater toxicity in OECD soil is not invariably accompanied by higher metal burdens. These include the presence of high concentrations of very toxic and highly available ions in laboratory tests and potential differences in the importance of soluble and total metal concentration for determining toxicity and body burdens.

The toxic effects of nickel on survival, growth, and reproduction of Eisenia veneta were investigated following 4 weeks of exposure to a nickel-chloride spiked loamy sand soil. The ability of a simple earthworm biomarker, the lysosomal membrane stability of coelomocytes, to reflect nickel exposure was also studied. Nickel caused a significant toxic effect on E.veneta at soil concentrations above 85 mg Ni/kg. Reproduction (cocoon production) was the most sensitive parameter being reduced at soil concentrations above 85 mg Ni/kg (EC10 = 85 mg Ni/kg). Survival of adults was only reduced at concentrations above 245 mg Ni/kg, while adult and cocoon wet weight were not affected by soil nickel concentrations up to 700 mg Ni/kg. The lysosomal membrane stability, measured as neutral-red retention time, was reduced at soil nickel concentrations similar to those that reduced reproduction, and demonstrated a dose-response relationship. The neutral-red retention time showed large individual variation for the earthworms within each exposure concentration. It was concluded that the lysosomal membrane stability, measured as neutral red retention time, has a potential role in risk assessment, but care should be taken conducting this test.

EC50s for cadmium, copper, lead and zinc were determined for juvenile production of Folsomia candida at pH6.0, 5.0 and 4.5 in a standard laboratory test system. In contrast to most previous studies where metal toxicity was increased at low pHs, in our experiments there was no clear relationship between soil acidity and EC50-reproduction in this species. The EC50-reproduction values (microgram g-1) for cadmium and zinc were similar at all three pHs (pH6.0: Cd 590, Zn 900; pH5.0: Cd 780, Zn 600; pH4.5: Cd 480, Zn 590). In contaminated field sites adjacent to primary zinc smelters, zinc is invariably present in soils at concentrations of at least 50 times that of cadmium. Thus deleterious effects of mixtures of these metals on populations of Collembola in such sites can be attributed to zinc rather than cadmium.

An assessment was performed of the risk to predators of cadmium, copper, lead and zinc in the food chain soil—earthworm—vertebrate. To estimate risk, the scheme proposed by Romijn et al. (1993, 1994) was used. The procedure compares mean bioconcentration factors (BCFs) (concentration in earthworms divided by concentration in soil) for the pollutants in prey with a predator sensitivity value. This allows maximum permissible concentrations (MPCs) to be determined for each metal. For the study, BCFs of the four metals were recorded in the tissues of earthworms collected from a number of sites located around a primary smelting works where soils are heavily contaminated with cadmium, copper, lead and zinc. Predator sensitivity was estimated using literature toxicity data as a hazardous concentration for 5% of species (HC5) by the technique of Aldenberg and Slob (1993). Comparison of field BCFs and literature HC5predator values gave MPCs for metals in soil of 0.017 μg Cd g−1, 18.9 μg Cu g−1, 30.4 μg Pb g−1 and 36.1 μg Zn g−1 which would theoretically protect 95% of predators from poisoning. A comparison of the calculated MPCs for cadmium, copper, lead and zinc with the concentrations of these metal found in a range of field soils indicates that the MPCs are almost always exceeded, even in uncontaminated agricultural soils. Possible causes for the overassessment of the risk of secondary poisoning are discussed and an alternative strategy based on the use of critical target organ levels is outlined.

The effects of cadmium, copper, lead and zinc on survival, growth, cocoon production and cocoon viability of the earthworm Eisenia fetida (Savigny) were determined in three experiments. In experiment 1, worms were exposed to single metals in standard artificial soil. For experiment 2, worms were maintained in contaminated soils collected from sites at different distances from a smelting works situated at Avonmouth, south-west England. In experiment 3, worms were exposed to mixtures of metals in artificial soil at the same concentrations as those present in the field soils. A survey of earthworm populations was carried out also. Population densities and species diversities of earthworms declined with proximity to the smelting works. No earthworms were found within 1 km of the factory. Comparison of toxicity values for the metals determined in the experiments indicated that zinc is most likely to be limiting earthworm populations in the vicinity of the works. Zinc was at least ten times more toxic to E. fetida in artificial soil than in contaminated soils collected from the field. This difference was probably due to the greater bioavailability of zinc in the artificial soil. The results are discussed in the context of setting 'protection levels' for metals in soils based on laboratory toxicity data.

Porcellio scaber Latreille (Crustacea: Isopoda) of one month in age were reared for a year on leaf litter of field maple (Acer campestre) contaminated in the laboratory with a range of concentrations of cadmium, copper, lead or zinc. The metals were applied topically to the leaves as nitrates. Growth and survival, numbers of live offspring produced by females that matured, and concentrations of metals in adult isopods at the end of the experiment were measured.'Critical concentrations' of metals in food at which all the isopods died before producing offspring were 100 μg Cd g(-1), 100 μg Cu g(-1), 2000 μg Pb g(-1) and 1000 μg Zn g(-1) (on a dry weight basis). The relative toxicities of the four metals in the laboratory were compared with concentrations of cadmium, copper, lead and zinc in surface leaf litter in the vicinity of a primary smelting works at Avonmouth, South West England. The results support the hypothesis that the absence of Porcellio scaber from sites in the immediate vicinity of the factory is due to zinc poisoning. Although cadmium is approximately ten times more toxic to isopods than zinc in the laboratory, zinc is most likely to be killing isopods in the field because its concentration is always at least 30 times higher than cadmium in Avonmouth leaf litter, and more than 100 times higher at most sites.Populations of Porcellio scaber survive in field sites where surface leaf litter contains up to 5000 μg Zn g(-1). This is at least five times higher than the 'critical concentration' in laboratory experiments. Thus, the methodology for assessing metal toxicity described in this paper, exaggerates the potential effects of metals to isopods in the field. Such differences between laboratory and field toxicities of metals should be taken into account when environmental protection levels for metals are being proposed for soil invertebrates based on ecotoxicological tests conducted in the laboratory.

The earthworm Eisenia fetida (Annelida: Oligochaeta) was exposed to a geometric series of concentrations of cadmium, copper, lead and zinc in artificial soil using the OECD recommended protocol. Mortality, growth and cocoon production were measured over 56 days to determine LC50 and EC50 values. No observed effect concentrations (NOECs) were also estimated. Furthermore, the percentage of viable cocoons and number of juveniles emerging per cocoon was recorded. Cocoon production was more sensitive than mortality for all the metals, particularly cadmium and copper for which NOEC reproduction values were an order of magnitude lower than those for NOEC mortality. However, there was no significant effect of metals on the viability of cocoons. The weights of earthworms declined in all treatments (including the controls) during the experiment. This was probably due to the lack of suitable food in the OECD standard soil medium used. It was concluded that future experiments should include animal manure in the test medium. The LC50, EC50 and NOEC values determined in this study were compared with concentrations of metals in soils in the vicinity of a smelting works at Avonmouth, southwest England. The 14-day LC50 for zinc in Eisenia fetida was exceeded in soils covering an area of 75 km2 around the works, compared to 4.2 km2 for copper and 4.7 km2 for lead. Soil values for cadmium did not exceed the LC50 value anywhere in the region. Similar estimates of relative effects on reproduction confirmed that zinc is most likely to be responsible for the absence of earthworms from sites close to the Avonmouth works. However, the OECD standard test overestimated the potential effects of metals on populations, since earthworms can be found as close as 1 km from the smelting works. The discrepancy between test and field observations was probably due to the greater availability of the metals in the artificial soil.

The capacity of species to adapt both physiologically and genetically to contaminants may allow populations to persist in pol- luted environments. Such 'adaptation' can have important implications for risk assessment, since it may mean that prediction based on extrapolation of toxicity studies with naive populations may prove invalid for long-term contaminated sites. To investigate the evolution of zinc resistance in Eisenia fetida, worms from a previously unexposed population (parent) were selected and reared over two generations (F1, F2) while exposed to zinc in the laboratory. Relative sensitivities of unexposed and selected generations were then compared by exposing parent, F1 and F2 individuals to zinc in contact filter papers tests. Calculation of eAect concentrations from this work indicated diAerences in sensitivity to zinc for successive generations, with higher toxicity values (LC50 ,L C90 ,L C99) found for the selected worms. The increases in resistance found for F1 and F2 worms were confirmed in a discriminating dose study. In addition to comparing the sensitivities of the parent, F1 and F2 generations for zinc, toxicity tests were also conducted with copper to assess if there was evidence of cross-resistance between the two metals. Results indicated similar increases in resis- tance to copper to those found for zinc. Mechanisms underlying the increased metal resistance were studied in toxicokinetic experiments. Results indicated no clear trends between the three generations indicating that physiological responses, other than diAerences in kinetic parameters, are responsible for the increased resistance found in the selected worms. # 2000 Elsevier Science Ltd. All rights reserved.

EC50s for cadmium, copper, lead, and zinc were determined for juvenile production of Folsomia candida Willem, 1902, at 25, 20, and 15 degrees C in a standard laboratory test system. Juvenile production of F. candida was too low at 25 degrees C for reliable EC50-reproduction values to be determined. The EC50-reproduction values (micrograms g-1) for cadmium, copper, and zinc were similar at both 20 and 15 degrees C (20 degrees C: Cd, 590; Cu, 700; Zn, 900; 15 degrees C: Cd, 540; Cu, 640; Zn, 590). Corresponding values for lead were considerably higher (20 degrees C: Pb, 2790; 15 degrees C: Pb, 1570). In aerially contaminated field sites adjacent to primary zinc smelters, zinc is invariably present in surface soils at concentrations of at least 50 times those of cadmium. The similarity of the EC50-reproduction values for cadmium and zinc in F. candida at 20 and 15 degrees C determined in this study strongly suggests that deleterious effects of mixtures of these metals on populations of Collembola in such sites can be attributed to zinc rather than cadmium.

Juvenile Eisenia fetida (Savigny) were exposed for 20 weeks to an uncontaminated soil and to soils contaminated with cadmium, copper, lead, and zinc collected from seven sites at different distances from a smelting works at Avonmouth, southwest England. The survival, growth (= weight after 5 weeks exposure), time to sexual maturation (= percentages of adults present after 8 weeks), and reproduction (= number of cocoons produced by the worms) were compared with soil metal concentrations. Of the parameters measured, growth and sexual maturation time had the lowest EC50 values. The effects of metal-contaminated soils could be attributed both to the direct toxicity of the metals and to changes in the "scope for growth" of the exposed worms. A comparison of the results with those of an earlier toxicity test conducted with adult worms indicated that juveniles are more sensitive to metals than adults. Significant toxic effects on the growth and sexual maturation times of juveniles were detected in soils from sites for which no significant effects on the cocoon production of adults could be detected. The greater sensitivity of juvenile worms indicates the importance of considering effects on a variety of life history stages when conducting a risk assessment of the effects of pollutants in soils. Although E. fetida does not occur naturally in soils at Avonmouth, the present study provides evidence to support the suggestion that pollution from the smelter is responsible for the absence of worms within 2 km of the factory. Results presented in this paper, and from previous studies, suggest the observed absence is due to the effects of zinc on the growth and maturation of juveniles and the cocoon production rate of adult worms.

Juveniles and adults of the Brown garden snail (Helix aspersa Mull.) were fed on an artificial diet contaminated with Zn (ca. 40-12,000 micrograms.g-1 dry wt), Cu (ca. 9-1600 micrograms.g-1 dry wt), pb (ca. 0.4-12,700 micrograms.g-1 dry wt), Cd (ca. 0.16-145 micrograms.g-1 dry wt), and all four metals mixed together for 120 days. Significant negative exponential regressions of food consumption and fecundity on concentrations were found for all treatments. Growth rate was affected significantly only by Zn and mixed treatments. The calculated EC20(consumption) values for juveniles were (in microgram.g1): Zn, 855; Cu, 248; Pb, 5290; Cd, 60; and for adults: Zn, 1240; Cu, 275; Pb, 3120; Cd, 147. In mixed treatment EC20(consumption) values were substantially lower indicating the additive effect of pollution with these four metals. EC20(consumption) for Zn in mixed treatment was 329 micrograms.g-1 for juveniles and 661 micrograms.g-1 for adults. The following EC20 values were estimated for fecundity (in micrograms.g-1): Zn, 1740; Cu, 533; Pb, 6140; Cd, 120; Zn in mixed treatment, 2210. The relative toxicities of the four metals were compared with their ratios in contaminated field sites. Comparing Zn and Cd, for example, even though Zn is ca. 13-24 times less toxic than Cd, it is usually present in plants and forest litter in concentrations ca. 100 times greater than those of Cd. Thus, of these two metals, Zn appeared to be potentially the most important pollutant in ecologically relevant situations. No effect of any treatment on mortality was found during the 4-month experiment. The calculated scenarios of population dynamics under the stress of chronic pollution with mixtures of the four metals revealed that the delayed reproduction due to estivation of snails may be the main cause of population decline at high metal concentrations in food. However, at concentrations at and below ca. 1000 micrograms Zn.g-1 in food, if the reproduction is not delayed the population may persist for a long time (0.25 control number after 50 years).

Accumulation of Zn, Cu, Pb and Cd was studied in snails fed for 120 days on diets contaminated with each metal separately and with all metals mixed together. The concentrations of Zn in food were in the range 39 to 12 200 mg kg −1 , Cu 9–1640 mg kg −1 , Pb 0.4–12 700 mg kg −1 , and Cd 0.16–146 mg kg −1 on a dry weight basis. At the highest concentrations of all metals the consumption rates decreased significantly. For the remaining concentrations, Zn and Cu were accumulated in soft tissue in proportion to their concentrations in food. The lowest treatments of Pb and Cd did not cause any increase in soft tissue concentrations of these metals but at average treatments, a clear increase was observed. Copper was accumulated especially efficiently, exceeding concentrations in food throughout the whole range of treatments. Except for the lower end of experimental treatments, Zn was accumulated approximately in direct proportion to its concentration in the diet. Lead was the most efficiently regulated metal, with soft tissue concentrations always substantially lower than in food. Approximately 60% of Zn, 90% of Cu, 43% of Pb and 68% of Cd on average was assimilated from food. The assimilation efficiency of food alone was ca 74%. The concentrations of metals in shells increased significantly with exposure, but (with one exception) the concentrations in shells did not exceed 5% of those found in soft tissue. We argue that snails are more important as agents of food-chain transport of Cu and Cd, than of Zn or Pb. Our results indicate also that snails are not able to deposit significant quantities of metals in their shells, at least during the time scale of our laboratory experiment.

A method is described for assessing the effects of metals on the food consumption rate of isopods from measurements of fecal production. The effects of zinc in the diets of two isopod species, Porcellio scaber and Oniscus asellus , were tested. The metal was fed to the isopods on leaves of field maple ( Acer campestre ) contaminated with concentrations ranging between 1000 and 10,000 μg Zn g −1 leaf dry wt. Significant reductions in feeding rates were observed of the highest concentrations of zinc. The test employed in this study is quick, cheap, and relevant for estimating sublethal effects of metals on isopods.

Terrestrial isopods (woodlice) have been the subject of numerous publications on the dynamics of metals in terrestrial invertebrates. They are of particular interest due to the ability of the hepatopancreas of woodlice to accumulate zinc, cadmium, lead and copper to very high concentrations. In a recent study, Hopkin showed that O. asellus from a zinc-contaminated site was able to excrete this metal at a faster rate than P. scaber when both species were fed an uncontaminated diet. In contrast, O. asellus had a greater affinity for cadmium and retained this metal to a much greater extent than P. scaber. In this paper, the rates of assimilation and excretion of two of these metals have been quantified by feeding O. asellus and P. scaber on leaves contaminated with radioactive isotopes of zinc and cadmium.

In this paper, an experiment is described on the assimilation of zinc, cadmium, lead, copper and iron by Dysdera crocata collected from a site in central Bristol. The spiders were fed on woodlice from their own site, and on woodlice from a site contaminated by a smelting works which contained much higher levels of zinc, cadmium and lead than the spiders would have been used to in their normal diet.

The concentrations of zinc, cadmium, lead and copper have been determined in the hepatopancreas, hindgut and rest of the body tissues of Oniscus asellus collected from eight sites in the U.K. The hepatopancreas is by far the most important storage organ of heavy metals, particularly cadmium, and at each site, contains a mean of at least 89% of the total body load of this element. Specimens of Oniscus asellus from contaminated sites may contain concentrations of zinc, cadmium, lead and copper in the hepatopancreas of about 1%, 0.5%, 2.5% and 3% of the dry weight respectively, which are among the highest so far recorded in the soft tissues of any animal.There is a significant positive correlation between the mean relative dry weight of the hepatopancreas of Oniscus asellus and the concentrations of zinc or cadmium in leaf litter from all eight sites. It is suggested that animals from sites which are contaminated heavily with zinc or cadmium have a large hepatopancreas because this enables them to 'de-toxify' a greater amount of the metal.

Des specimens de L.v. sont collectes dans un bois de feuillus contamine par les metaux lourds et dans une zone similaire, non contaminee; ils sont nourris de tissus d'Oniscus asellus contenant des quantites connues de divers metaux lourds. Les resultats sont variables selon le metal considere et l'origine des O.a. mais on peut en conclure que O.a. ne forme pas une part importante du regime de L.v. dans les forets de feuillus