title: Toxicity interaction between chlorpyrifos, mancozeb and soil moisture to the terrestrial isopod Porcellionides pruinosus.
abstract: A main source of uncertainty currently associated with environmental risk assessment of chemicals is the poor understanding of the influence of environmental factors on the toxicity of xenobiotics. Aiming to reduce this uncertainty, here we evaluate the joint-effects of two pesticides (chlorpyrifos and mancozeb) on the terrestrial isopod Porcellionides pruinosus under different soil moisture regimes. A full factorial design, including three treatments of each pesticide and an untreated control, were performed under different soil moisture regimes: 25%, 50%, and 75% WHC. Our results showed that soil moisture had no effects on isopods survival, at the levels assessed in this experiment, neither regarding single pesticides nor mixture treatments. Additivity was always the most parsimonious result when both pesticides were present. Oppositely, both feeding activity and biomass change showed a higher sensitivity to soil moisture, with isopods generally showing worse performance when exposed to pesticides and dry or moist conditions. Most of the significant differences between soil moisture regimes were found in single pesticide treatments, yet different responses to mixtures could still be distinguished depending on the soil moisture assessed. This study shows that while soil moisture has the potential to influence the effects of the pesticide mixture itself, such effects might become less important in a context of complex combinations of stressors, as the major contribution comes from its individual interaction with each pesticide. Finally, the implications of our results are discussed in light of the current state of environmental risk assessment procedures and some future perspectives are advanced.
authors.affiliation: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: ruimorgado@ua.pt.
authors.forename: Rui G
authors.initials: RG
authors.lastname: Morgado
authors.affiliation: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Pedro A D
authors.initials: PA
authors.lastname: Gomes
authors.affiliation: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Nuno G C
authors.initials: NG
authors.lastname: Ferreira
authors.affiliation: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Diogo N
authors.initials: DN
authors.lastname: Cardoso
authors.affiliation: Environmental Protection Authority, Level 10, 215 Lambton Quay, Private Bag 63002, Wellington 6140, New Zealand.
authors.forename: Miguel J G
authors.initials: MJ
authors.lastname: Santos
authors.affiliation: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal; Programa de Pós-Graduação em Produção Vegetal, Universidade Federal do Tocantins, Campus de Gurupi. Rua Badejós, Zona Rural, Cx. Postal 66, CEP: 77402-970, Gurupi-TO, Brazil.
authors.forename: Amadeu M V M
authors.initials: AM
authors.lastname: Soares
authors.affiliation: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: sloureiro@ua.pt.
authors.forename: Susana
authors.initials: S
authors.lastname: Loureiro
mesh_terms: D000818:Animals; D004390:Chlorpyrifos / Q000633:toxicity*; D004347:Drug Interactions; D005247:Feeding Behavior / Q000187:drug effects; D033321:Isopoda / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D008344:Maneb / Q000633:toxicity*; D010575:Pesticides / Q000633:toxicity*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000633:toxicity*; D014867:Water / Q000032:analysis; D015038:Zineb / Q000633:toxicity*
chemical_list: D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; D014867:Water; D008344:Maneb; D004390:Chlorpyrifos; C013099:mancozeb; D015038:Zineb
keywords: Climate change; Generalized linear models; Independent action model; Mixtures; Multiple stressors; Pesticides