Role In Distribution Of Metals Research Articles

Ocean Acidification-Mediated Food Chain Transfer of Polonium between Primary Producers and Consumers.

Phytoplankton and zooplankton are key marine components that play an important role in metal distribution through a food web transfer. An increased phytoplankton concentration as a result of ocean acidification and warming are well-established, along with the fact that phytoplankton biomagnify 210Po by 3−4 orders of magnitude compared to the seawater concentration. This experimental study is carried out to better understand the transfer of polonium between primary producers and consumers. The experimental produced data highlight the complex interaction between the polonium concentration in zooplankton food, i.e. phytoplankton, its excretion via defecated fecal pellets, and its bioaccumulation at ambient seawater pH and a lower pH of 7.7, typical of ocean acidification scenarios in the open ocean. The mass of copepods recovered was 11% less: 7.7 pH compared to 8.2. The effects of copepod species (n = 3), microalgae species (n = 3), pH (n = 2), and time (n = 4) on the polonium activity in the fecal pellets (expressed as % of the total activity introduced through feeding) was tested using an ANOVA 4. With the exception of time (model: F20, 215 = 176.84, p < 0.001; time: F3 = 1.76, p = 0.16), all tested parameters had an impact on the polonium activity (copepod species: F2 = 169.15, p < 0.0001; algae species: F2 = 10.21, p < 0.0001; pH: F1 = 9.85, p = 0.002) with complex interactions (copepod x algae: F2 = 19.48, p < 0.0001; copepod x pH: F2 = 10.54, p < 0.0001; algae x pH: F2 = 4.87, p = 0.009). The experimental data underpin the hypothesis that metal bioavailability and bioaccumulation will be enhanced in secondary consumers such as crustacean zooplankton due to ocean acidification.

Spatial Variability and Influencing Factors of Cr, Ni, Cu, Zn and Pb in Five Mangroves Reserves of South China

In order to study the spatial variability and influencing factors of heavy metals contents in five mangroves in South China, surface sediments and plant canopy new leaves of mangroves were sampled to determine Cr, Ni, Cu, Zn, Pb contents. Moreover, the corresponding pollution load index of sediments and bioconcentration factors of leaves were evaluated. Meanwhile, the physical and chemical properties, organic carbon and nitrogen of surface sediments and new leaves were measured. It was found that the average content of heavy metals in the surface sediments of Futian Reserve was the highest with a pollution load index of 2.61, classified as strongly polluted. The particle size distribution of the five sites was mainly silt-sand, and the pH was slightly acidic. Multivariate analysis of variance indicated that both sampling locations and vegetation types had significant influences on heavy metal contents in surface sediments and leaves as well as bioconcentration factors of leaves. In sum, natural factors such as plant species and organic matter contents significantly influence the metal contents and translocation in mangrove forests. However, in strongly polluted areas anthropogenic factors compromise the natural effects and play the major role in metal distribution.

Role of sediment size in the distribution and abundance of metals in a tropical (Sharavati) estuary, west coast of India

Two sediment cores representing adjacent mudflat and mangrove sub-environments from the middle region of Sharavati estuary were analyzed for sand, silt, clay and organic carbon at 2-cm interval. Metal concentration was also analyzed for all bulk sediment samples and selected samples for different sediment size fractions (sand (4O), medium silt (6O) and clay (8O) of both the cores for Aluminium (Al), Iron (Fe), Manganese (Mn), Nickel (Ni), Zinc (Zn), Copper (Cu), Cobalt (Co), and Chromium (Cr). The sediments of mudflat environment are found to be enriched with metals, organic carbon (OC) associated with finer sediments. However, the core collected from the mangrove environment showed higher coarser material. The association and degradation of organic matter played important role in distribution of metals in silt and clay fractions in mudflat core. The paper also discusses on source of sediments and process involved with time. Higher enrichment factor (EF) values of Zn in silt and clay fraction and Co in sand and silt fraction are observed in the mangrove core as compared to mudflat core, whereas, Cu is enriched in the silt and clay fraction of mudflat core. However, Cr was enriched in all the fractions of both the cores. Pollution load index (PLI) indicated higher metal enrichment in the clay fraction of both the cores.

Colloidal organic matter from wastewater treatment plant effluents: Characterization and role in metal distribution

Colloidal organic matter from wastewater treatment plants was characterized and examined with respect to its role in metal distribution by using tangential flow ultrafiltration, liquid chromatography coupled with organic carbon and UV detectors, and an asymmetrical flow field-flow fractionation (AFlFFF) multidetection platform. Results revealed that a humic-like fraction of low aromaticity with an average molar mass ranging from 1600 to 2600Da was the main colloidal component. High molar mass fractions (HMM), with molar mass ranges between 20 and 200kDa, were present in lower proportions. Ag, Cd, Cu, Cr, Mn and Zn were found mainly in the dissolved phase (<0.45μm) and their distribution between colloidal and truly dissolved fractions was strongly influenced by the distribution of dissolved organic carbon. AFlFFF coupled to ICP-MS showed that Ag, Cd, Cu, Cr, Mn and Zn associate to the low molar mass fraction of the colloidal pool, whereas Al, Fe and Pb were equally bound to low and high molar mass fractions.