Sediment Toxicity Testing with the Amphipod <i>Grandidierella Japonica</i> and Effects of Sediment Particle Size Distribution

Abstract

The brackish and marine amphipod Grandidierella japonica is an organism well-suited to sediment toxicity testing in Japan, where no other sentinel amphipod species are found. To provide the application example of toxicity testing using G. japonica in Japan, we performed 10-day whole sediment toxicity tests of six estuarine sediment samples collected from estuaries and tidal rivers flowing into Tokyo Bay. While all the tested sediment samples were not lethally toxic to this species, the body length increment of surviving amphipods was significantly different among sediment samples. To verify that the observed growth inhibition was caused not by large proportions of fine particles but by chemical contamination, additional 10-day tests using formulated sediment with different particle size distributions were performed. As the result, sediment containing more than 25% of < 63 μm particles could reduce the body length, but the reduced body length in the sediment collected from Heisei bridge (S3) was demonstrated to be due to chemical contamination, not due to fine particles. The species characteristics and test results presented in this study provide fundamental information to interpret the results of whole sediment toxicity tests.

Mind the Exposure Gaps—Modeling Chemical Transport in Sediment Toxicity Tests

“…The contribution of the bound fraction to the overall uptake of chemicals in sediment toxicity tests has also been a debated issue. ,,,, It remains to be clarified if an increase in bioaccumulation would result from accelerated uptake kinetics into the organism or if uptake of DOC-bound chemicals leads to overall higher organism concentrations compared to water-only exposure. In any case, such an effect is expected to be higher for more hydrophobic chemicals that show significant binding to DOC .…”

Development and application of a metabolomic tool to assess exposure of an estuarine amphipod to pollutants in the environment

“…The response values of the control samples were < 0.5 in most models (Figure 4), suggesting that the models apply to the new samples. Compared with the chemical property of the samples, 9,23 the result of the models seemed to be inconsistent with the presence of the target chemicals in the sediment samples. The models were built based on the metabolomic responses, and they should include the consideration of bioavailability.…”

“…Two road samples (RD1, RD3 samples) were collected from the metropolitan expressway by road sweeping vehicles as previously reported. 9,23 The concentrations of heavy metals and organic pollutants are summarized in Table S1.…”

“…b Sample information from a previous study. 23 c Sample information from a previous study. 9 d The m/z value for the component.…”

“…The estuarine amphipod, Grandidierella japonica, was used as a test species in this study, because it has been used in acute and chronic sediment toxicity tests. 23,24 This species is indigenous to Japan but has recently been documented in the Mediterranean Sea. 25…”