Department of Analytical Chemistry, Institute of Biomolecules (INBIO), Faculty of Sciences, CEI-MAR, University of Cadiz, Campus Rio S. Pedro, E-11510, Puerto Real, Cadiz, Spain.
Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Campus Ensenada, Km. 103 Carr. Tijuana-Ensenada, Ensenada 22800, Baja California, Mexico.
Sci Total Environ. 2016 Feb 1;543(Pt A):248-266. doi: 10.1016/j.scitotenv.2015.11.033. Epub 2015 Nov 18.
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<Fe<Cd≈Pb<Ni≈Co<<Cu. Lastly, a strong correlation (r(2)=0.87, p<0.01) was found between average reactive trace metal concentrations and metal concentrations measured in Armandia brevis (a deposit-feeding Opheliid polychaete), suggesting that these labile sedimentary metals are preferentially accumulated by the polychaete, making it a useful biomonitor of sedimentary metal exposure.
痕量金属（Cd、Co、Cu、Fe、Mn、Ni、Pb、Zn）在恩塞纳达和埃尔绍萨尔港（墨西哥）的沉积物中，采用两种操作定义的组分（HCl 和黄铁矿）进行了测定。在两个港口，HCl 组分中的金属浓度明显高于黄铁矿组分，这突出表明大多数痕量金属与黄铁矿结合的趋势较弱。例外的是，Cu 高度黄铁矿化，两个港口的痕量金属黄铁矿化程度（DTMP）均大于 80%。溶解态 Fe 通量测量与固相 Fe 硫化物数据相结合表明，每年在恩塞纳达港有 98 公吨的 Fe 作为硫化铁沉淀下来。这些硫化铁（和相关的痕量金属）将保留在沉积物中，除非它们受到疏浚或沉积物再悬浮的干扰。计算表明，疏浚活动可能会将 0.20±0.13 至（0.30±0.56）×10(3) 公吨的 Cd 和 Cu 分别输出到开阔海域，对海洋底栖生物构成潜在威胁。恩塞纳达和埃尔绍萨尔港的黄铁矿化程度（DOP）相对较低（<25%），而硫化程度（DOS）较高（~50%），这是由于酸可挥发硫化物的贡献。DOP 值与 DTMP 值相关（p≤0.001），表明随着这种矿物的形成，金属逐渐被纳入黄铁矿。两个港口的 DTMP 值与-log（Ksp(MeS)/Ksp(pyr)）之间也存在显著相关性，表明痕量金属掺入黄铁矿相是相应金属硫化物的溶度积函数。两个港口中元素黄铁矿化的顺序为 Zn≈Mn<Fe<Cd≈Pb<Ni≈Co<<Cu。最后，在 Armandia brevis（一种以沉积物为食的 Opheliid 多毛类）中，发现平均反应性痕量金属浓度与测量的金属浓度之间存在很强的相关性（r(2)=0.87，p<0.01），这表明这些不稳定的沉积态金属优先被多毛类动物积累，使其成为沉积态金属暴露的有用生物监测物。
