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Environmental Toxicology and Chemistry, Vol. 22, No. 4, p. 691 2003q 2003 SETAC

Printed in the USA0730-7268/03 $12.00 1 .00

Editorial

ORGANIC CONTAMINANTS IN SOIL

For scientists, there is no shortcut to performing serioussoil ecotoxicology. A fate description of the contaminants isincluded to explain effects; sometimes the effect assessmentmust be used to point to the presence of a chemical even thoughthe fate is not clearly understood. Details of fate and effectsare sometimes useless for risk assessment due to a lack ofprecision or a failure to link convincingly the fate to the effectsor the biological parameters to the healthiness of the ecosys-tem. This is not a surprise in the single risk assessment casebecause limited resources preclude an iterative research strat-egy to reveal the mechanisms.

Widespread risk assessment practices based on legislation,however, provide shortcuts by requiring an effect assessmentderived from single-species laboratory tests. To derive pre-dicted no-effect concentrations (PNECs) such tests have hith-erto been used in connection with assessment factors and morerecently with species sensitivity distribution models [1]. Thelatter assumes that the PNEC can be based on a complementof independent single-species toxicity data. During a confer-ence held in Copenhagen Denmark that focussed on the fateand effects of organic contaminants in soil, it was shown thatspecies interactions indeed are important for the toxicity levelsof the individual species. Multispecies tests performed in astandardized manner are now slowly emerging, and they ob-viously include species interactions. Realism is gained at thecost of interpretability. This does not pose a problem, however,because interpretability is not paramount for risk assessment.

There is still an important need to integrate the availableinformation on the effects of all kinds of factors exerting en-vironmental influences. Aging and bioavailability of the or-ganic contaminants must be included and will greatly changethe ecotoxicological setting of limit concentration in soil [2].Subtle knowledge of chemical fate and effects is useless inthe process of making sound environmental risk assessment ifconcomitant disturbances from other human or natural sourcesare not included. The risk assessment procedure would gainrespect from all parties—academia, industry and environmen-tal protection agencies—if it could be done in an integratedrisk assessment process. Soil management in agriculture is a

good example of an important factor whose impact can sur-mount effects of chemicals in many cases or change bioavail-ability in others. The reluctance to provide more environmentalinformation is not rational; improved risk assessments willmost probably ease the burden of administrating low-limit val-ues and ensure that hazard is not overestimated.

Variability in soil physicochemical properties represents asubstantial scientific challenge to understanding the toxicologyof soil contaminants. Bioavailability of organic soil contam-inants became the driving theme of the Copenhagen meeting,and the role of this subject will have increased importance inthe future. Scientists must focus on the general applicabilityof their results and consider the soil-aging factor as a majorsink of persistent organic compounds. The political importanceof this subject was clearly demonstrated: One leading Danishnewspaper devoted its front page to quoting Martin Alexanderon the role of aging in risk assessment of contaminated soils.

In this issue of Environmental Toxicology and Chemistryyou will find a selection of papers presenting current researchon biodegradation and chemical availability.

Paul Henning KroghSoil Fauna and Ecotoxicology Research Unit

National Environmental Research InstituteDenmark

Kaj HenriksenAalborg University

Denmark

Carsten Suhr JacobsenGeological Survey of Denmark and Greenland

Denmark

REFERENCES1. Jensen J, Løkke H, Holmstrup M, Krogh PH, Elsgaard L. 2001.

Effect and risk assessment of linear alkylbenzene sulphonates inagricultural soil. 5. Risk assessment of LAS in sludge amendedsoils. Environ Toxicol Chem 20:1690–1697.

2. Alexander M. 2000. Aging, bioavailability, and overestimationof risk from environmental pollutants. Environ Sci Technol 34:4259–4265.