Short exposure of Artemia salina to group-12 metals: Comparing hatchability, mortality, lipid peroxidation, and swimming speed.

The hatchability, mortality rate, lipid peroxide levels, and swimming speed of Artemia salina have been compared based on short exposures of ZnCl2, CdCl2, and HgCl2 in artificial seawater. The hatching tests were carried out for 12, 24, 36, and 48 h at 28 °C. Mortality rate and lipid peroxide (LPO) levels were determined after 24 h of exposure at 28 °C, in the dark, and on living larvae using the FOX method. The swimming speed was determined after 24 h using a microcomputer coupled to a digital camera, with simultaneous treatment of the recorded images every 25 s, at 25 °C, under red-light irradiation. Results showed that Zn caused a gradual inhibition of the hatching for concentrations <900 µmol L-1; however, Cd and Hg displayed almost complete inhibition for concentrations ≤100 µmol L-1. Also, the heavy metals caused a dose-dependent increase of mortality (LD50) in the following order: Zn = 3290 µmol L-1 < Cd = 2206 µmol L-1 < Hg = 15.6 µmol L-1. Furthermore, significant LPO levels were found for Cd (1500-2000 µmol L-1, p < 0.001) and Hg (5-20 µmol L-1, p < 0.001). Finally, the swimming speed values increased significantly, for Zn ≈ 2.5 mm s-1 (1500 µmol L-1, p < 0.001), Cd ≈ 3.5 mm s-1 (2000 µmol L-1, p < 0.05), and Hg ≈ 4.0 mm s-1 (15 µmol L-1, p < 0.05), after 24 h exposure. There is a clear dose-dependent toxicity, indicating that Zn, Cd and Hg can induce significant changes in hatchability, mortality, and ethological and biochemical parameters.

Evaluation of iron loading in four types of hepatopancreatic cells of the mangrove crab Ucides cordatus using ferrocene derivatives and iron supplements.

The mangrove crab Ucides cordatus is a bioindicator of aquatic contamination. In this work, the iron availability and redox activity of saccharide-coated mineral iron supplements (for both human and veterinary use) and ferrocene derivatives in Saline Ucides Buffer (SUB) medium were assessed. The transport of these metallodrugs by four different hepatopancreatic cell types (embryonic (E), resorptive (R), fibrillar (F), and blister (B)) of U. cordatus were measured. Organic coated iron minerals (iron supplements) were stable against strong chelators (calcein and transferrin). Ascorbic acid efficiently mediated the release of iron only from ferrocene compounds, leading to redox-active species. Ferrous iron and iron supplements were efficient in loading iron to all hepatopancreatic cell types. In contrast, ferrocene derivatives were loaded only in F and B cell types. Acute exposition to the iron compounds resulted in cell viability of 70-95%, and to intracellular iron levels as high as 0.40 µmol L-1 depending upon the compound and the cell line. The easiness that iron from iron metallodrugs was loaded/transported into U. cordatus hepatopancreatic cells reinforces a cautionary approach to the widespread disposal and use of highly bioavailable iron species as far as the long-term environmental welfare is concerned.