Trace metals partitioning among different sedimentary mineral phases and the deposit-feeding polychaete Armandia brevis.

Trace metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were determined in two operationally defined fractions (HCl and pyrite) in sediments from Ensenada and El Sauzal harbors (Mexico). The HCl fraction had significantly higher metal concentrations relative to the pyrite fraction in both harbors, underlining the weak tendency of most trace metals to associate with pyrite. Exceptionally, Cu was highly pyritized, with degrees of trace metal pyritization (DTMP) >80% in both harbors. Dissolved Fe flux measurements combined with solid phase Fe sulfide data indicated that 98 mt of Fe are precipitated as iron sulfides every year in Ensenada Harbor. These Fe sulfides (and associated trace metals) will remain preserved in the sediments, unless they are perturbed by dredging or sediment resuspension. Calculations indicate that dredging activities could export to the open ocean 0.20±0.13 to (0.30±0.56)×10(3) mt of Cd and Cu, respectively, creating a potential threat to marine benthic organisms. Degrees of pyritization (DOP) values in Ensenada and El Sauzal harbors were relatively low (<25%) while degrees of sulfidization (DOS) were high (~50%) because of the contribution of acid volatile sulfide. DOP values correlated with DTMP values (p≤0.001), indicating that metals are gradually incorporated into pyrite as this mineral is formed. Significant correlations were also found between DTMP values and -log(Ksp(MeS)/Ksp(pyr)) for both harbors, indicating that incorporation of trace metals into the pyrite phase is a function of the solubility product of the corresponding metal sulfide. The order in which elements were pyritized in both harbors was Zn≈Mn

Early genotoxic response and accumulation induced by waterborne copper, lead, and arsenic in European seabass, Dicentrarchus labrax.

Cu, Pb, and As, which are among the most abundant metals in the aquatic environment, are also among the most health-threatened by causing diverse cellular injuries. The aim of this study was to assess and compare the potential early induction of genotoxic effects after waterborne Cu, Pb, and As exposure in European seabass, Dicentrarchus labrax, a commercial widely cultured fish, using the micronucleus (MN) assay in peripheral blood erythrocytes. Fish were exposed under laboratory conditions to nominal solutions ranging 0-10 mg/L for 24 and 96 h. Furthermore, actual metal ion concentrations were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) or differential pulse anodic stripping voltammetry (DPASV) in water and four fish tissues differentially related to environmental exposition and metal accumulation, i.e. the gills, liver, muscle, and brain. Dose-dependent increases of micronuclei (MNi) frequency were observed after these very short exposures; based on measured metal concentrations in water, the genotoxic effect ordered as Cu > As > Pb. Significant genotoxic effect at 0.009 mg/L Cu, 0.57 mg/L Pb, and 0.01 mg/L As was seen. For Cu and Pb these are only slightly higher, but for As it is notably lower than the USEPA criteria of maximum concentration to prevent acute toxicity in aquatic organisms. Furthermore, genotoxicity was differentially related to metal accumulation. MNi frequency correlated positively with the content of Pb in all the organs, with the content of As in liver and gills and only with the content of Cu in the brain. In conclusion, our findings raised environmental concerns because these depicted a genotoxic potential of Cu, Pb, and As after a very short exposure to low but environmentally relevant concentrations, too close to regulatory thresholds. In addition, the MN test in D. labrax could be considered an early biomarker of genotoxicity induced by these metals in fish.

Applicability of 2-hydroxybenzaldehyde benzoylhydrazone in the determination of trace metals by adsorptive cathodic stripping voltammetry: relevancy of simultaneous determinations.

The applicability of 2-hydroxybenzaldehyde benzoylhydrazone (2-HBBH) for determining Cd(II), Cu(II), Pb(II) and Bi(III) ions by adsorptive cathodic stripping voltammetry was studied. The sensitivity of metal reduction peak currents was highly enhanced with the addition of 2-HBBH to metallic solutions, showing the adsorptive characteristics of the complexes. Variable factors affecting the response (mainly: the influences of pH, supporting electrolyte and deposition potential on selectivity and sensitivity) were investigated. Limits of detection suitable for trace analysis were obtained: 0.28 microg L(-1) for Cd(II) at pH 10; 0.026 microg L(-1) for Pb(II) at pH 9; 0.285 microg L(-1) for Bi(III) at pH 8 and 0.051 microg L(-1) for Cu(II) at pH 9.5. Simultaneous determinations of two groups of elements, consisting of Cd(II)-Pb(II)-Cu(II) and Cd(II)-Pb(II)-Bi(III), at pH 9.5 and 9, respectively, were described with good resolution and sensitivities. Metals were quantified at concentrations in the range from 0.5 to 14 microg L(-1). The RSD at a concentration level of 5 microg L(-1) of metal was 4.28% for Cd(II), 2.99% for Pb(II), 4.82% for Bi(III) and 1.35% for Cu(II). The method was applied to the simultaneous determination of metals in certified reference water (TMDA-62) and in synthetic water samples with satisfactory results.