Biological assessment of contaminated land using earthworm biomarkers in support of chemical analysis

• Published in: The Science of the total environment 2004-09, Vol.330 (1), p.9-20
• Main Authors: Hankard, Peter K., Svendsen, Claus, Wright, Julian, Wienberg, Claire, Fishwick, Samantha K., Spurgeon, David J., Weeks, Jason M.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Bioassay; Biological and medical sciences; Biomarkers - analysis; Contaminated land; Ecotoxicology, biological effects of pollution; Environmental Monitoring - methods; Fundamental and applied biological sciences. Psychology; Heavy Metal Poisoning; Immune System - physiology; Industrial Waste; Lysosomes - physiology; Neutral red retention; Oligochaeta; Oligochaeta - physiology; Polycyclic Aromatic Hydrocarbons - analysis; Polycyclic Aromatic Hydrocarbons - poisoning; Risk assessment; Soil Pollutants - analysis; Soil Pollutants - poisoning; Survival Analysis; Terrestrial environment, soil, air; Total immune assay
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2003.08.023

Biological indicators can be used to assess polluted sites but their success depends on the availability of suitable assays. The aim of this study was to investigate the performance of two earthworm biomarkers, lysosomal membrane stability measured using the neutral red retention assay (NRR-T) and the total immune activity (TIA) assay, that have previously been established as responsive to chemical exposure. Responses of the two assays were measured following in situ exposure to complexly contaminated field soils at three industrial sites as well as urban and rural controls. The industrial sites were contaminated with a range of metal (cadmium, copper, lead, zinc, nickel and cobalt) and organic (including polycyclic aromatic hydrocarbons) contaminants, but at concentrations below the ‘New Dutch List’ Intervention concentrations. Exposed earthworms accumulated both metals and organic compounds at the contaminated sites, indicating that there was significant exposure. No effect on earthworm survival was found at any of the sites. Biomarker measurements, however, indicated significant effects, with lower NRR-T and TIA found in the contaminated soils when compared to the two controls. The results demonstrate that a comparison of soil pollutant concentrations with guideline values would not have unequivocally identified chemical exposure and toxic effect for soil organisms living in these soils. However, the earthworm biomarkers successfully identified significant exposure and biological effects caused by the mixture of chemicals present.