Transfer of heavy metals in the food chain earthworm Black-tailed godwit (Limosa limosa): comparison of a polluted and a reference site in The Netherlands.

The Black-tailed godwit (Limosa limosa) is a migratory wader that favours wet meadows for breeding. The species has a Red List status in The Netherlands, as it strongly declined in numbers since the 1960s. Intensification of agriculture and land use change resulting in habitat loss are considered major causes of this decline. In some areas the breeding habitat is contaminated with heavy metals. Adult godwits mainly feed on earthworms in the breeding season, which are known to accumulate heavy metals from the soil. In this paper we investigate the transfer of heavy metals from the soil to the Black-tailed godwit, which may have an additive negative effect on the viability of local populations. We measured heavy metal concentrations in soil, earthworms, and godwit eggs and feathers at a polluted and a reference site. The results suggest that Lead, Mercury and Cadmium are transferred from the soil to godwits even though the species spends only a few months in the breeding area during the year.

Population growth and development of the earthworm Lumbricus rubellus in a polluted field soil: possible consequences for the godwit (Limosa limosa).

Many soils are polluted with mixtures of moderate levels of contaminants. In The Netherlands 175,000 sites in rural areas are classified as highly polluted. However, it remains unclear to what extent local ecosystems are endangered. In this paper, we report on the effect of contaminants on earthworms in a meadow system. We tested a polluted and a reference field soil with similar soil characteristics and agricultural use. In the polluted soil copper, mercury, and lead were elevated by more than 200% compared with the reference soil. Bioassays on growth and reproduction in the earthworm species Lumbricus rubellus were executed in both soils, and a population model was used to assess the population-level consequences of changes in growth and reproduction. No significant effects were seen on reproduction and survival in L. rubellus, but development was retarded in the polluted soil. This resulted in a 23% lower growth rate and a change in demography toward younger individuals. Field data on population composition of earthworms were used to support the laboratory results, and the relevance of the results for the godwit (Limosa limosa), which mainly feeds on earthworms during the breeding season, is discussed.

C60 exposure induced tissue damage and gene expression alterations in the earthworm Lumbricus rubellus.

Effects of C60 exposure (0, 15 or 154 mg/kg soil) on the earthworm Lumbricus rubellus were assessed at the tissue and molecular level, in two experiments. In the first experiment, earthworms were exposed for four weeks, and in the second lifelong. In both experiments, gene expression of heat shock protein 70 (HSP70) decreased. For catalase and glutathione-S-transferase (GST), no significant trends in gene expression or enzyme activity were observed. Gene expression of coelomic cytolytic factor-1 (CCF-1) did not alter in earthworms exposed for four weeks, but was significantly down-regulated in the lifelong exposure. Histology of earthworms exposed to C60 in both experiments showed a damaged cuticle, with underlying pathologies of epidermis and muscles, as well as effects on the gut barrier. However, tissue repair was also observed in these earthworms. Overall, these data show that sub-lethal C60 exposure to earthworms via the soil affects gene expression and causes tissue pathologies.

Effects of soil properties on food web accumulation of heavy metals to the wood mouse (Apodemus sylvaticus).

Effects of soil properties on the accumulation of metals to wood mice (Apodemus sylvaticus) were evaluated at two sites with different pH and organic matter content of the soil. pH and organic matter content significantly affected accumulation of Cd, Cu, Pb and Zn in earthworms and vegetation. For Cd, Cu and Zn these effects propagated through the food web to the wood mouse. Soil-to-kidney ratios differed between sites: Cd: 0.15 versus 3.52, Cu: 0.37 versus 1.30 and Zn: 0.33-0.83. This was confirmed in model calculations for Cd and Zn. Results indicate that total soil concentrations may be unsuitable indicators for risks that metals pose to wildlife. Furthermore, environmental managers may, unintentionally, change soil properties while taking specific environmental measures. In this way they may affect risks of metals to wildlife, even without changes in total soil concentrations.