Bioaccumulation and molecular effects of sediment-bound metals in zebrafish embryos

Abstract

Predicting the bioavailability and effects of metals in sediments is of major concern in context with sediment risk assessment. This study aimed to investigate the bioavailability and molecular effects of metals spiked into riverine sediments to zebrafish (Danio rerio) embryos. Embryos were exposed to a natural and an artificial sediment spiked with cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) individually or as a mixture at concentrations ranging from 150 to 3000 mg/kg dry weight (dw) over 48 h, and uptake of metals was determined. Furthermore, transcript abundances of the metallothioneins MT1 and MT2, the metal-responsive element-binding transcription factor (MTF) and the genes sod1, hsp70 and hsp90α1 were measured as indicators of metal-induced or general cellular stress. D. rerio embryos accumulated metals from sediments at concentrations up to 100 times greater than those spiked to the sediment with the greatest bioaccumulation factor (BAF) for Cu from artificial sediment (275.4 ± 41.9 (SD)). Embryos accumulated greater concentrations of all metals from artificial than from natural sediment, and accumulation was greater when embryos were exposed to individual metals than when they were exposed to the mixture. Exposure of embryos to Zn or the mixture exhibited up to 30-fold greater transcript abundances of MT1, MT2 and hsp70 compared to controls which is related to significant uptake of Zn from the sediment. Further changes in transcript abundances could not be related to a significant uptake of metals from sediments. These studies reveal that metals from spiked sediments are bioavailable to D. rerio embryos directly exposed to sediments and that the induction of specific genes can be used as biomarkers for the exposure of early life stages of zebrafish to metal-contaminated sediments.

Effects of cadmium, manganese, and lead on locomotor activity and neurexin 2a expression in zebrafish

“…In the present study, to better analyze the behavioral changes, the treatment doses were chosen based on the malformation rate reached at approximately 40% at 120 hpf to optimize the analysis of behavioral changes. Moreover, consistent with previous studies [24,35], we found that all 3 metals accumulated in the zebrafish tissue.…”

“…Moreover, consistent with previous studies[24,35], we found that all 3 metals accumulated in the zebrafish tissue. The most predominant malformations caused by treatment with Cd, Mn, and Pb were yolk sac edema, pericardial edema, and curly spinal cord, respectively.…”

A versatile and low-cost open source pipetting robot for automation of toxicological and ecotoxicological bioassays

“…The LC 50 values for the static- and semi-static exposure were comparable to previously published values determined using zebrafish embryos, which were 30.1 mg L -1 [36] and 14.1 mg L -1 [37], respectively.…”

Multi-Anti-Parasitic Activity of Arylidene Ketones and Thiazolidene Hydrazines against Trypanosoma cruzi and Leishmania spp.

“…This could be explained by assuming that permeation of chemicals is reduced by the chorion as for organic pollutants and lipophilic drugs [ 31 , 32 , 33 ]. For that reason, it is necessary to take into account two parameters: bioaccumulation and chorion permeability [ 33 ].…”