Search

This study investigated acute arsenic toxicity and bioconcentration capacity in Litopenaeus vannamei because it has been frequently exposed to lower salinities than its isosmotic point (25 g L -1 ). Juveniles (9.9 ± 0.4 g) were exposed to low (5-10 g L -1 ) and isosmotic salinity (25 g L -1 ) levels; As values were 30.8, 20.2, 16.8 and 13.9 mg L -1 at 5 g L -1 ; 30.4, 19.1, 16.8 and 14.8 mg L -1 at 10 g L -1 ; 31.5, 19.0, 15.0 and 11.9 mg L -1 at 25 g L -1 at 24, 48, 72 and 96 h LC 50 , respectively. No significant differences were found among As LC 50 values calculated for different salinity levels and same exposure times, concluding that low salinity did not affect shrimp sensitivity to As. Likewise, no significant differences were observed in As bioconcentration in shrimp exposed to the same waterborne As and distinct salinity, supporting the results of acute toxicity. Bioconcentration factors of As maintained a relatively stable tendency where all values (0.8 ± 0.2 to 1.7 ± 0.4) were statistically comparable to 1, indicating that As was accumulated in a similar proportion to waterborne As concentration at three salinity levels. This study proposed 135.3 ± 12.1 μg L -1 for salinities from 5 to 25 g L -1 as provisional safe As concentration. According to these results, the hypothesis that sustains an effect of low salinity on As acute toxicity and its bioconcentration capacity cannot be acceptable. Therefore, the information provided allows knowing the threshold levels of As in water to avoid ecological and economic losses., (Copyright © 2018 Elsevier Inc. All rights reserved.)

In this study, the concentration of six metal(loid)s was examined in the fish Oreochromis aureus collected from El Comedero dam during a massive mortality event induced by a mine tailing spill. A major spill (~ 300,000 m3) of waste was released into the San Lorenzo River System following a rupture in the tailing dam of a mining plant in NW Mexico; consequently, the discharged material flowed into El Comedero dam. The accumulation of metal(oid)s in the tissues of O. aureus showed higher levels in the liver than in the guts and muscle. Concentrations in the liver were high (As, 1.1–1063; Cd, 8.9–392; Cu, 372–59,129; Hg, 0.46–19.79; Se, 8.7–748; and Zn, 116–820 μg g−1), revealing that these fish were exposed to high concentrations of these elements. The mortality of fish could have resulted from the combined effect of the six analyzed metal(loid)s, as well as other residues present in mine tailings. [ABSTRACT FROM AUTHOR]