title: Development of acute and chronic sediment bioassays with the harpacticoid copepod Quinquelaophonte sp.
abstract: Reliable environmentally realistic bioassay methodologies are increasingly needed to assess the effects of environmental pollution. This study describes two estuarine sediment bioassays, one acute (96 h) and one chronic (14 d), with the New Zealand harpacticoid copepod Quinquelaophonte sp. utilising behavioural and reproductive endpoints. Spiked sediments were used to expose Quinquelaophonte sp. to three reference compounds representing important categories of estuarine chemical stressors: zinc (a metal), atrazine (a pesticide), and phenanthrene (a polycyclic aromatic hydrocarbon). Acute-to-chronic ratios (ACR) were used to further characterise species responses. Acute sediment (sandy and low total organic content) 96 h EC50 values for the sublethal inhibition of mobility for zinc, atrazine and phenanthrene were 137, 5.4, and 2.6 µg/g, respectively. The chronic EC50 values for inhibition of reproduction (total offspring) were 54.5, 0.0083, and 0.067 µg/g for zinc, atrazine, and phenanthrene, respectively. For phenanthrene, a potentially novel mode of action was identified on reproduction. Quinquelaophonte sp. was found to be more sensitive than several other estuarine species indicating choice of test organism is important to characterising the effects of environmentally relevant levels of contamination. The bioassay sediment results demonstrate the sensitivity and suitability of Quinquelaophonte sp. as a tool for the assessment use of estuarine health.
authors.affiliation: School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand; Landcare Research, PO Box 40, Lincoln 7640, New Zealand. Electronic address: tristanjstringer@gmail.com.
authors.forename: Tristan J
authors.initials: TJ
authors.lastname: Stringer
authors.forename: Chris N
authors.initials: CN
authors.lastname: Glover
authors.forename: Vaughan
authors.initials: V
authors.lastname: Keesing
authors.forename: Grant L
authors.initials: GL
authors.lastname: Northcott
authors.forename: Sally
authors.initials: S
authors.lastname: Gaw
authors.forename: Louis A
authors.initials: LA
authors.lastname: Tremblay
mesh_terms: D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D001681:Biological Assay; D033342:Copepoda / Q000187:drug effects*; D019015:Geologic Sediments / Q000737:chemistry; D009520:New Zealand; D010616:Phenanthrenes / Q000633:toxicity*; D015203:Reproducibility of Results; D012098:Reproduction / Q000187:drug effects; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015032:Zinc / Q000633:toxicity*
chemical_list: D010616:Phenanthrenes; D014874:Water Pollutants, Chemical; C031181:phenanthrene; D015032:Zinc; D001280:Atrazine
keywords: Estuary; New Zealand; Pollution; Reproduction; Toxicity