Extrapolation of the laboratory-based OECD earthworm toxicity test to metal-contaminated field sites

Abstract

: 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.

Determining the bioavailability and toxicity of lead contamination to earthworms requires using a combination of physicochemical and biological methods

“…Grelle and Descamps (1998) also found that soil total Pb concentration was a better predictor of earthworm body burden than CaCl 2 -extractable Pb levels. Previous studies demonstrated that soil physicochemical properties have a significant impact on Pb uptake by E. andrei (Spurgeon and Hopkin, 1995;Peijnenburg et al, 1999;Bradham et al, 2006;Smith et al, 2012). For example, soil pH has been suggested as the most important factor for controlling the bioavailability of Pb in soil, followed by organic matter content (Thomas, 1997;Peijnenburg et al, 1999).…”

Earthworm ( Eisenia Fetida ) Bioassay to Assess the Possible Effects of Platinum Tailings Disposal Facilities on the Environment Along a Gradient

“…Cd, Co and Pb were all higher than the TCs but lower than the IC and SBs for all the sites (TDF−15 km). The effects of Cr [18,19], Cu [20,21], Ni [22] and Zn [23] on either growth or reproduction of earthworms has been reported on. These reported effects were, however, at higher metal concentrations than found in the present study, but it has to be taken into account that these studies were conducted using single metals as contaminants.…”

Earthworms Eisenia fetida affect the uptake of heavy metals by plants Vicia faba and Zea mays in metal-contaminated soils

“…Many other studies have reported the metal's toxicity to earthworms, tested both in artificial and field soil (Neuhauser et al, 1985;Spurgeon et al, 1994;Spurgeon and Hopkin 1995). They concluded that the toxic effects of metals were less severe in field soils (Spurgeon and Hopkin, 1995). It should be noted that simultaneous exposure to several metals can also lead to antagonistic, not necessarily to additive or synergistic effects, as observed by Khalil et al (1996).…”

“…In our study, soil pH remained in the neutral to slightly alkaline range. Many other studies have reported the metal's toxicity to earthworms, tested both in artificial and field soil (Neuhauser et al, 1985;Spurgeon et al, 1994;Spurgeon and Hopkin 1995). They concluded that the toxic effects of metals were less severe in field soils (Spurgeon and Hopkin, 1995).…”