Trace metal

About: Trace metal is a research topic. Over the lifetime, 5125 publications have been published within this topic receiving 181046 citations.

Accumulation of Trace Metals by Mangrove Plants in Indian Sundarban Wetland: Prospects for Phytoremediation

Abstract: The work investigates on the potential of ten mangrove species for absorption, accumulation and partitioning of trace metal(loid)s in individual plant tissues (leaves, bark and root/pneumatophore) at two study sites of Indian Sundarban Wetland. The metal(loid) concentration in host sediments and their geochemical characteristics were also considered. Mangrove sediments showed unique potential in many- fold increase for most metal(loid)s than plant tissues due to their inherent physicochemical properties. The ranges of concentration of trace metal(loid)s for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in plant tissue were 0.006-0.31, 0.02-2.97, 0.10-4.80, 0.13-6.49, 4.46-48.30, 9.2-938.1, 0.02-0.13, 9.8-1726, 11-5.41, 0.04-7.64, 3.81-52.20 μg g (-1)respectively. The bio- concentration factor (BCF) showed its maximum value (15.5) in Excoecaria agallocha for Cd, suggesting that it can be considered as a high-efficient plant for heavy metal bioaccumulation. Among all metals, Cd and Zn were highly bioaccumulated in E. agallocha (2.97 and 52.2 μg g (-1) respectively. Our findings suggest that the species may be classified as efficient metal trap for Cd in aerial parts, as indicated by higher metal accumulation in the leaves combined with BCF and translocation factor (TF) values.

Trace metal uptake rates in crustaceans (amphipods and crabs) from coastal sites in NW Europe differentially enriched with trace metals

Abstract: This study set out to investigate the possible effect of life history strategy on the trace metal biology of crustaceans living in coastal sites contaminated by high availabilities of toxic metals. Amphipods brood their young, parents and offspring staying in the same habitat. Therefore a population of amphipods living in a trace-metal-rich estuary would have been selected over generations for any physiological adaptation reducing the potential toxic action of the trace metals, such as reduced rates of uptake of metals from solution. Crabs, on the other hand, are dispersed by a planktonic larval phase, the zoea, increasing the probability that the parents of individuals inhabiting a metal-rich estuary would have lived in a remote location not exposed to selection pressure to reduce metal uptake rates. Uptake rates of the dissolved trace metals Zn, Cd and Ag were, therefore, measured in amphipods Orchestia gammarellus and crabs Carcinus maenas and Pachygrapsus marmoratus from coastal sites in Britain and France exposed to different degrees of trace metal enrichment, in order to test 3 hypotheses: (1) the mean metal uptake rates of amphipods and crabs from a metal-rich site would be lower than those of the same crustaceans from a control site; (2) the mean metal uptake rates of amphipods would show a greater reduction from those of control amphipods than would those of equivalent crabs; (3) the mean metal uptake rates of amphipods from metal-rich sites would show smaller coefficients of variation than those of equivalent crabs. In practice the mean metal uptake rates of both amphipods and crabs did not show consistent significant differences between the crustaceans from the metal-rich and control sites. Furthermore there was no evidence to conclude that the coefficients of variation of the mean uptake rates of amphipods from the relatively metal-rich sites are lower than those of crabs from the same sites. It is concluded that the exposure of the crustaceans to raised trace metal availabilities has not been sufficient to select for a reduction in dissolved trace metal uptake rates, even in the case of the in situ populations of amphipods. It is relevant that a suite of physiological mechanisms for the amelioration of the potential toxic effects of trace metals is available to coastal invertebrates, and it remains possible that other physiological processes promoting metal tolerance may be active to differing degrees in crustaceans from metal-rich habitats.

Metallophores and Trace Metal Biogeochemistry

Abstract: Trace metal limitation not only affects the biological function of organisms, but also the health of ecosystems and the global cycling of elements. The enzymatic machinery of microbes helps to drive critical biogeochemical cycles at the macroscale, and in many cases, the function of metalloenzyme-mediated processes may be limited by the scarcity of essential trace metals. In response to these nutrient limitations, some organisms employ a strategy of exuding metallophores, biogenic ligands that facilitate the uptake of metal ions. For example, bacterial, fungal, and graminaceous plant species are known to use Fe(III)-binding siderophores for nutrient acquisition, providing the best known and most thoroughly studied example of metallophores. However, recent breakthroughs have suggested or established the role of metallophores in the uptake of several other metallic nutrients. Furthermore, these metallophores may influence environmental trace metal fate and transport beyond nutrient acquisition. These discoveries have resulted in a deeper understanding of trace metal geochemistry and its relationship to the cycling of carbon and nitrogen in natural systems. In this review, we provide an overview of the current state of knowledge on the biogeochemistry of metallophores in trace metal acquisition, and explore established and potential metallophore systems.

Entrainment of trace-metal-enriched Atlantic-shelf water in the inflow to the Mediterranean Sea

Abstract: Surface waters of the Mediterranean Sea have higher trace-metal concentrations than open Atlantic surface waters1. This observation could be explained by sources within the basin, but recent data from the Alboran Sea2 indicate that trace metals may already be enriched in Atlantic waters flowing into the Mediterranean through the Strait of Gibraltar. Here we present new data documenting the presence of trace-metal-enriched source waters west of the Strait, and present a mathematical analysis showing that Cu, Ni, Cd and Zn distributions in the Alboran Sea can be explained as linear mixtures of four well–defined sources: (1) Spanish coastal waters, (2) North Atlantic Central Water, (3) Atlantic surface water, and (4) Mediterranean Levantine Intermediate Water. In this analysis, salinity and trace metals are used for the first time to deconvolve mixing between water masses of different origins.

Bioavailability of Trace Metals

Abstract: Metals external to the organism are unlikely to cause any adverse effect in that organism but may do so once absorbed (or taken up) and assimilated. This implies that as a prelude step, metals have to come in contact with the organism to be of any benefit or consequence to that organism. In turn, metals have to be in a particular form to be able to enter an organism. In essence, for a contaminant to be assimilated, it will have to be mobile and transported and be bioavailable to the organism. Because bioavailability (also known as bioaccessibility) may have different meanings to different disciplines, it is prudent to define it according to the receptor organism.