title: Sensitivity of the invasive bivalve Corbicula fluminea to candidate control chemicals: The role of dissolved oxygen conditions.
abstract: The freshwater Corbicula fluminea is a major aquatic nuisance worldwide. Current pest control methods raise cost-effectiveness and environmental concerns, which motivate research into improved mitigation approaches. In this context, the susceptibility of the clams to chemicals under reduced oxygen conditions was examined. Biocides with different mechanisms of toxicity (niclosamide, polyDADMAC, ammonium nitrate, potassium chloride and dimethoate) were tested under normoxic (>7 mg L(-1) dissolved O2) and hypoxic (<2 mg L(-1) dissolved O2) conditions. Hypoxia was observed to potentiate chemical treatment, particularly when combined with non-overwhelming doses that would produce only intermediate responses by themselves. For niclosamide, ammonium nitrate and dimethoate, clam mortality enhancements up to 400% were observed under hypoxia as compared to dosing upon normal dissolved oxygen conditions. For polyDADMAC and potassium chloride, substantially lower mortality enhancements were found. The differences in the clams' sensitivity to the chemicals under hypoxia could be linked to the expected mechanisms of action. This suggests that judicious selection of the biocide is essential if optimized combined control treatments are to be designed and provides an insight into the interference of frequent hypoxia events in the response of natural clam populations to contaminant loads.
authors.affiliation: Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Inês C
authors.initials: IC
authors.lastname: Rosa
authors.affiliation: CIEPQPF - Research Centre for Chemical Process Engineering and Forest Products, Department of Chemical Engineering, University of Coimbra, Pólo II, Rua Sílvio Lima, 3030-790 Coimbra, Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: Garrido
authors.affiliation: Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Ré
authors.affiliation: Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Gomes
authors.affiliation: Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Joana L
authors.initials: JL
authors.lastname: Pereira
authors.affiliation: Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Gonçalves
authors.affiliation: CIEPQPF - Research Centre for Chemical Process Engineering and Forest Products, Department of Chemical Engineering, University of Coimbra, Pólo II, Rua Sílvio Lima, 3030-790 Coimbra, Portugal. Electronic address: raquel@cantab.net.
authors.forename: Raquel
authors.initials: R
authors.lastname: Costa
mesh_terms: D000818:Animals; D049874:Corbicula / Q000502:physiology*; D005068:Eutrophication; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical
keywords: Asian clam; Biofouling; Hypoxia; Pest control; Toxicity