Acute and chronic toxicity of polychlorinated biphenyl 126 to Tigriopus japonicus: Effects on survival, growth, reproduction, and intrinsic rate of population growth

Abstract

The harpacticoid copepod Tigriopus japonicus has a wide geographical distribution and is considered as a suitable model species for the assessment of toxicity of marine pollutants. The aim of the present study was to test the impacts of polychlorinated biphenyl (PCB) 126 (3,3',4,4',5-pentachlorobiphenyl) on the growth, development, and reproduction of T. japonicus in two successive generations. We first quantified the 96-h 50% lethal concentration (2.83 mg/L; all reported concentrations are nominal values), the no-observed-effect concentration (0.6 mg/L), and the lowest-observed-effect concentration (LOEC; 1.2 mg/L) of PCB126 in the nauplii. Nauplii were more sensitive than the adults, which still survived at the highest tested PCB126 concentration (8 mg/L). In the chronic toxicity testing, 10 life history traits were quantified for T. japonicus. No obvious effect on any of these traits was observed in the first generation (F0) at tested concentrations (<100 µg/L) lower than the LOEC. During the second generational life-cycle exposure (F1), however, PCB126 had an obvious toxic effect on the reproduction (>1 µg/L) and growth (>0.1 µg/L). Thus, copepods became more sensitive to PCB126 exposure as generations developed. Among the different traits tested, body size was the most sensitive parameter. Reproduction (fecundity, number of clutches, nauplii/clutch) and intrinsic population growth were also significantly impacted by PCB exposure. The survivorship, sex ratio, hatching time, and development were not affected. Environmental risk assessment of contaminants must therefore be based on a long-term multigenerational exposure to provide a realistic measurement of the influences of pollutants on aquatic life.

Impacts of mercury exposure on life history traits of Tigriopus japonicus: Multigeneration effects and recovery from pollution

“…Similarly, Guo et al (2012) found that the copepod T. japonicus became more sensitive to PCB 126 exposure as generations developed. Together with other studies (Guo et al, 2012;Massarin et al, 2010;Pane et al, 2004), this work highlights that the offspring may become more sensitive to pollutant exposure or that the toxic effects can accumulate with generations.…”

“…Similarly, Guo et al (2012) found that the copepod T. japonicus became more sensitive to PCB 126 exposure as generations developed. Together with other studies (Guo et al, 2012;Massarin et al, 2010;Pane et al, 2004), this work highlights that the offspring may become more sensitive to pollutant exposure or that the toxic effects can accumulate with generations. Lee et al (2008) reported that, of the seven traits (nauplius phase, development time, survival, sex ratio, number of clutch, nauplii per clutch, and fecundity), only the length of the nauplius phase and development time in T. japonicus displayed a greater sensitivity to several marine pollutants including copper and arsenic during a two-generation life cycle exposure, which is inconsistent with our study.…”

“…This copepod is relatively small, the adults being approximately, 1.0 mm generally. Its life cycle includes twelve distinct postembryonic developmental stages, i.e., six nauplius stages, five copepodid stages, and one adult stage (Guo et al, 2012;Raisuddin et al, 2007). Notably, this species is easily raised in the laboratory and has a short generation time, hence making multi-generational experiments feasible (Guo et al, 2012;Kwok et al, 2009;Lee et al, 2008).…”

“…Its life cycle includes twelve distinct postembryonic developmental stages, i.e., six nauplius stages, five copepodid stages, and one adult stage (Guo et al, 2012;Raisuddin et al, 2007). Notably, this species is easily raised in the laboratory and has a short generation time, hence making multi-generational experiments feasible (Guo et al, 2012;Kwok et al, 2009;Lee et al, 2008). In this study, via a multigenerational life-cycle test, T. japonicus were exposed to different mercuric chloride (HgCl 2 ) treatments (i.e., the nominal concentrations with 0, 0.5, 1, 10, and 50 g/L in the seawater respectively) for five consecutive generations (F0-F4), and it was followed by a recovery period of one generation (F5) in seawater control conditions.…”

Alleviation of mercury toxicity to a marine copepod under multigenerational exposure by ocean acidification

“…This copepod inhabits tide pools on rocky shores along the coasts in the Western Pacific including Japan, South Korea, and China 36 , and thus it may have suffered from multi-stresses (e.g., OA and Hg pollution) due to human activities. We specifically examined the combined effects of OA and Hg on the multigenerational life history of this copepod.…”