15 NOVEMBER 1999
J.A. Lindley, P. Donkin, S.V. Evans, C.L. George, K.F. Uil-1999
Journal of Experimental Marine Biology and Ecology, 242 (1): 59-74
Abstract:
Two organochlorine compounds, pentachlorophenol (PCP), a respiratory uncoupler, and 1,2-dichlorobenzene (DCB), a non-polar narcotic, were selected for experiments on their toxicity to eggs of estuarine and neritic planktonic calanoid copepods. Experiments on freshly laid eggs in aqueous solutions of the toxicants showed that no viable nauplii of Eurytemora affinis or Acartia bifilosa hatched from eggs incubated in initially saturated solutions and a reduced percentage of eggs hatched after temporary exposure (~16 h) to saturated solutions. The percentage of eggs of E. affinis that hatched was reduced below control values in 5 and 10% saturated solutions with EC50 (concentration reducing the response by 50%) estimated at 2.1% saturated solution of PCP and 3.2% saturated DCB (initial concentrations). Viability of nauplii was reduced at lower concentrations with estimated LC50 (concentration lethal to 50% of population) values of 0.7% saturated PCP and 1.7% saturated DCB. Equivalent values for Acartia bifilosa were higher, with no reduction below control values in percentage hatch at 10% saturation and LC50 values for nauplii of 0.8% PCP and 14.2% DCB. The percentage of eggs of A. clausi that hatched when incubated in sealed vials to eliminate loss of DCB through evaporation was not reduced in 10% saturated solutions but the estimated LC50 was 2.0% saturation. In sediment exposed to a saturated solution of DCB very high mortality occurred within 1 day.
(Centre for Coastal and Marine Sciences, Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, UK)