Influence of environmental changes on degradation of chiral pollutants in soils

• Published in: Nature (London) 1999-10, Vol.401 (6756), p.898-901
• Main Authors: Lewis, David L, Garrison, A. Wayne, Wommack, K. Eric, Whittemore, Alton, Steudler, Paul, Melillo, Jerry
• Format: Article
• Language: English
• Subjects: 2,4-Dichlorophenoxyacetic Acid - analogs & derivatives; 2,4-Dichlorophenoxyacetic Acid - chemistry; 2,4-Dichlorophenoxyacetic Acid - metabolism; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Anthropogenic factors; Applied ecology; Assessments; Biodegradation, Environmental; Biological and medical sciences; Biological effects; Brazil; Carcinogenicity; Chemical pollutants; Chemical pollution; Degradation; Ecotoxicology, biological effects of pollution; Enantiomers; Endocrine disruptors; Energy; Environment; Environmental changes; Environmental perception; Fundamental and applied biological sciences. Psychology; Genotypes; Herbicides; Humanities and Social Sciences; Insecticides; Insecticides - chemistry; Insecticides - metabolism; letter; Microorganisms; Microscopy; multidisciplinary; Mutagenicity; Norway; Nutrients; Organophosphorus compounds; Organophosphorus Compounds - chemistry; Organophosphorus Compounds - metabolism; Organophosphorus pesticides; Pasture; PCB; Pesticides; Phthalates; Phytotoxicity; Pollutants; Polychlorinated biphenyls; Public health; Radiation; Ratios; Science; Science (multidisciplinary); Soil; Soil and water pollution; Soil Microbiology; Soil Pollutants - metabolism; Soil pollution; Soil science; Soils; Stereoisomerism; Terrestrial environment, soil, air; Toxicity; United States; X-rays
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/44801

Numerous anthropogenic chemicals of environmental concern-including some phenoxy acid herbicides, organophosphorus insecticides, polychlorinated biphenyls, phthalates, freon substitutes and some DDT derivatives-are chiral. Their potential biological effects, such as toxicity, mutagenicity, carcinogenicity, and endocrine disrupter activity, are generally enantiomer-selective, and different enantiomers are preferentially degraded (transformed) by micro-organisms in various environments. Here we use field and laboratory experiments to demonstrate that environmental changes in soils can alter these preferences, and to suggest that the preferences shift owing to different groups of related microbial genotypes being activated by different environmental changes. In Brazilian soils, almost all pasture samples preferentially transformed the non-herbicidal enantiomer of dichlorprop ((RS)-2-(2,4-dichlorophenoxy)propionic acid), while most forest samples either transformed the herbicidal enantiomer more readily or as rapidly as the non-herbicidal enantiomer. Organic nutrient enrichments shifted enantioselectivity for methyl dichlorprop ((RS)-methyl 2-(2,4-dichlorophenoxy)propionic acid) strongly towards preferentially removing the non-herbicidal enantiomer in soils from Brazil and North America, potentially increasing phytotoxicity of its residues relative to that of the racemate. Assessments of the risks chemical pollutants pose to public health and the environment need to take into account the chiral selectivity of microbial transformation processes and their alteration by environmental changes, especially for pesticides as up to 25 per cent are chiral.