title: A Meta-Analysis Evaluating the Relationship between Aquatic Contaminants and Chironomid Larval Deformities in Laboratory Studies.
abstract: Chironomid larval deformities have been widely investigated as an aquatic pollution toxicity end point. Field chironomid surveys often show a spatial association between contaminants and deformities, suggesting contaminants cause deformities. However, over 40 years of laboratory assays have not been able to confirm this causality. We therefore conducted a review of the literature and meta-analysis, in order to (A) assess whether trends across assays indicated dose-response effects, (B) characterize the consistency of results, and (C) investigate whether experimental issues and publication bias were contributing to inconsistency and/or reducing confidence in results. The experimental issues we investigated were extraneous nonchemical laboratory stressors (which may mask or interact with chemical effects), and mortality (which can confound deformity results). Our meta-analysis of the most commonly tested chemicals suggested dose-response effects for copper, but not lead or zinc. However, we also found substantial inconsistency across studies. Both mortality and extraneous stressors were potentially contributing to this inconsistency, reducing confidence in most published data. We observed no evidence of publication bias. We conclude that any causal link between contaminants and deformities remains uncertain, and suggest improved experimental and data reporting procedures to better assess this relationship.
authors: Centre for Aquatic Pollution Identification and Management (CAPIM), BioSciences 4, School of BioSciences, The University of Melbourne , Melbourne, Victoria 3010 Australia.
authors: Bryant S
authors: BS
authors: Gagliardi
authors: Centre for Aquatic Pollution Identification and Management (CAPIM), BioSciences 4, School of BioSciences, The University of Melbourne , Melbourne, Victoria 3010 Australia.
authors: Vincent J
authors: VJ
authors: Pettigrove
authors: Centre for Aquatic Pollution Identification and Management (CAPIM), Bio21 Institute and School of BioSciences, The University of Melbourne , 30 Flemington Road, Parkville, Victoria 3010 Australia.
authors: Sara M
authors: SM
authors: Long
authors: Centre for Aquatic Pollution Identification and Management (CAPIM), Bio21 Institute and School of BioSciences, The University of Melbourne , 30 Flemington Road, Parkville, Victoria 3010 Australia.
authors: Ary A
authors: AA
authors: Hoffmann
mesh_terms: D000818:Animals; D001681:Biological Assay; D002683:Chironomidae; D003300:Copper / Q000494:pharmacology; D007814:Larva / Q000187:drug effects*; D015032:Zinc / Q000633:toxicity*
chemical_list: D003300:Copper; D015032:Zinc