Trace metal

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

Modeling seasonal and spatial contamination of surface waters and upper sediments with trace metal elements across industrialized urban areas of the Seybouse watershed in North Africa

Abstract: Industrialization and urbanization are the main sources of pollutions worldwide and particularly in developing countries. This study aims the determination of anthropogenic inputs with trace metals in aquatic ecosystems at the Plain of Annaba (NE Algeria), which is known as one of the largest industrial areas in Africa. Samples of surface waters and upper sediments were conducted in six stations: four in Meboudja wadi and two in Seybouse wadi. Contents of iron, copper, chromium, nickel, zinc, and manganese were measured by atomic absorption spectrophotometry, whereas Cd and Pb were determined using electrothermal atomic absorption spectrometry. Measurements of Hg were carried out using atomic fluorescence. Spatiotemporal variations of metal concentrations were tested using generalized linear models (GLM), whereas the influence of water pollution on sediment contamination was tested with generalized additive models (GAMs). Metal contents measured in surface water and sediments varied differently from upstream to downstream of the study wadis and between seasons. The results showed that the surface water was polluted with high levels of iron, nickel, chromium, lead, and cadmium. Values of the contamination index revealed that the surface sediments were contaminated by iron, chromium, lead, and cadmium. The GAMs indicated that water-phase metal concentrations had no significant effects on trace metal concentrations in the sediment. This suggests that seasonal metal concentrations in water phase, which are measured during the study period (2012) and are time-dependent, contribute increasingly and gradually over time-not immediately-to the accumulation of metals into the sediments. Therefore, the long-term accumulation of metals in the sediments resulted from the continuous discharges of metals in the water phase. The anthropogenic impacts are marked by high contaminations of Meboudja wadi particularly in downstream areas of the steel factory and the nearby industrial areas. The direct industrial discharges into the water and atmosphere (iron, lead, cadmium) as well as urban disposals and agricultural activities are at the origin of these contaminations.

Trace metal concentrations in Posidonia oceanica of North Corsica (northwestern Mediterranean Sea): use as a biological monitor?

Abstract: Within semi-closed areas like the Mediterranean Sea, anthropic wastes tend to concentrate in the environment. Metals, in particular, are known to persist in the environment and can affect human health due to accumulation in the food chain. The seagrass Posidonia oceanica, widely found in Mediterranean coastal waters, has been chosen as a "sentinel" to quantify the distribution of such pollutants within the marine environment. Using a technique similar to dendrochronology in trees, it can act as an indicator of pollutant levels over a timeframe of several months to years. In the present study, we measured and compared the levels of eight trace metals (Cr, Ni, Cu, Zn, As, Se, Cd, and Pb) in sheaths dated by lepidochronology and in leaves of shoots sampled from P. oceanica meadows collected from six offshore sites in northern Corsica between 1988 and 2004; in the aim to determine 1) the spatial and 2) temporal variations of these metals in these areas and 3) to compared these two types of tissues. We found low trace metal concentrations with no increase over the last decade, confirming the potential use of Corsican seagrass beds as reference sites for the Mediterranean Sea. Temporal trends of trace metal concentrations in sheaths were not significant for Cr, Ni, Cu, As or Se, but Zn, Cd, and Pb levels decreased, probably due to the reduced anthropic use of these metals. Similar temporal trends between Cu levels in leaves (living tissue) and in sheaths (dead tissue) demonstrated that lepidochronology linked with Cu monitoring is effective for surveying the temporal variability of this metal. Leaves of P. oceanica can give an indication of the metal concentration in the environment over a short time period (months) with good accuracy. On the contrary, sheaths, which gave an indication of changes over long time periods (decades), seem to be less sensitive to variations in the metal concentration in the environment. Changes in human consumption of metals (e.g., the reduction of Pb in fuel) are clearly reflected in both organs. These results confirm that P. oceanica is a good bioindicator of metals and a good biomonitor species for assessing Cu in the environment.

Simultaneous assessment of environmental impact on condition and trace metal availability in zebra mussels Dreissena polymorpha transplanted into the Wiltz River, Luxembourg. Comparison with the aquatic moss

Abstract: Caged freshwater mussels Dreissena polymorpha were transplanted for three months at ten sites along the Wiltz River in the North of the Grand-Duchy of Luxembourg. Three different biological parameters were employed to assess the physiological condition of the molluscs after 27, 51, 75, and 90 days of exposure: mortality, reattachment success, and dry weight. Besides the introduced zebra mussels, translocated aquatic mosses, Fontinalis antipyretica, were employed as a second trace metal indicator, though with a different experimental design. The moss tufts were replaced in toto every time the mussels were sampled in order to separately monitor temporal changes in the water metal levels. The biological responses of the mussels and trace metal accumulation in their tissues reflected the successive major anthropogenic impacts on the river. The differences observed in the biological significance of the examined condition parameters suggest the use of several descriptors in combination for an accurate in situ assessment of the biological impact of water pollution. The precise localization of metal input sources (i.e., natural Cd, Pb and industrial Cd, Cr, Cu, Sn) and the assessment of their spatial impact were particularly successful with Dreissena polymorpha. The major factor influencing metal concentrations in the molluscs was the change in dry weight. This source of variability could be eliminated by the calculation of metal body burdens. The comparison of the contamination profiles in mussels and in mosses revealed specific accumulation properties for both indicators. In particular, Cr and Sn were hardly detected in the bryophytes. The coherent data obtained for Cd, Cu, and Pb suggest that the monitoring results in translocated zebra mussels remained reliable even when severe changes in the condition of the molluscs occurred.