Copper toxicity in the marine copepod Tigropus japonicus: low variability and high reproducibility of repeated acute and life-cycle tests.
The intertidal copeopod Tigriopus japonicus, which is abundant and widely distributed along the coasts of Western Pacific, has been suggested to be a good marine ecotoxicity testing organism. In this study, a series of experiments were conducted to investigate the reproducibility and variability of copper (Cu) sensitivity of T. japonicus so as to evaluate its potential to serve as an appropriate test species. To understand the seasonal variation of Cu sensitivity, individuals of T. japonicus were collected from the field in summer and winter, and subjected to standard 96 h acute (static renewal) toxicity tests. 96 h-LC50 values of T. japonicus collected from the two seasons were marginally different (p = 0.05), with an overall coefficient of variation (CV) of 33%. Most importantly, our results indicated that chronic Cu sensitivity of T. japonicus was highly reproducible. The CVs of intrinsic rates of increase in the population of the control and Cu treatment (10 microg Cu l(-1)) groups were only 10-11% between 10 runs of a standardised complete life-cycle test. Moreover, different Cu(II) salts generally resulted in a similar 96 h-LC50 value while Cu(I) chloride was consistently slightly less toxic than Cu(II) salts. Given such a high reproducibility of toxic responses, it is advocated to use T. japonicus as a routine testing organism.
Kwok
Kevin W H
KW
The Swire Institute of Marine Science, Faculty of Science, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong, China. h0104885@hkusua.hku.hk
Leung
Kenneth M Y
KM
Bao
Vivien W W
VW
Lee
Jae-Seong
JS
D000818:Animals; D033342:Copepoda / Q000187:drug effects* / Q000254:growth & development*; D003300:Copper / Q000633:toxicity*; D007928:Lethal Dose 50; D008018:Life Cycle Stages / Q000187:drug effects*; D008386:Marine Biology; D015203:Reproducibility of Results; D012621:Seasons; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D014874:Water Pollutants, Chemical; D003300:Copper