Duration of life‐cycle toxicity tests with the ostracod Heterocypris incongruens

Abstract

An acute sediment toxicity test using the ostracod Heterocypris incongruens is user friendly and has high sensitivity; however, a life-cycle test using this species has not been developed. The most challenging problem when developing a life-cycle test is that the egg development time varies greatly and is sometimes too long (> 150 d) to monitor. It is desirable to shorten the duration of life-cycle toxicity tests including the observation period of egg development while preserving the ecological relevance of the net reproductive rate (R ), an endpoint in the life-cycle test. Therefore, in the present study, we suggest a practical test duration for R using population growth rate (λ) as a measure of ecological relevance. We collected a range of life history characteristics of the ostracod by combining data from the literature and experimental results, constructed population matrix models, and calculated λ for 20 life history patterns. The results showed that a longer test period (> 150 d) did not increase the correlation coefficients between R and λ. Rather, a shorter test duration resulted in R being highly correlated with λ. Our results suggest that a life-cycle toxicity test using the ostracod can provide an ecologically relevant toxicity endpoint, even if the test is abandoned after approximately 50 d and unhatched eggs remain. Environ Toxicol Chem 2017;36:3443-3449. © 2017 SETAC.

Bioconcentration of Organotin Cations during Molting Inhibits Heterocypris incongruens Growth

“…Despite the need for further study, we deem our model a worthwhile complementary method to evaluate sediments in Flanders. Applying the approach to more spatiotemporal and geochemical settings , will evaluate its broader applicability. Thus, we deem it a starting point for more integrated ecotoxicity modeling in general.…”

“…As a combination of species from different trophic levels and effect endpoints characterizes an ecosystem’s resilience, − bioassays/test batteries for daphnia, algae, midge larvae, or bacteria , are common to establish a weight of evidence approaches for sediment quality. Toxic effects vary not only between organisms and life stages , but also due to differences in exposure regimes and sediment properties: one can use the solution as extracted from sediment to evaluate “dissolved” contaminants or exposure to whole sediment to elucidate more integrated effects.…”