Seasonal Variations Of Trace Metals Research Articles

Seasonal variations of trace metals from water and sediment samples in the northern Bay of Bengal.

We aimed to determine the temporal variation of trace metals concentrations in surface water and surface sediment samples at Kutubdia Channel, Bangladesh. Trace metals of samples were detected using energy dispersive X-ray fluorescence (Energy-dispersive X-ray spectroscopy) method. The lowest concentration of metals was found in water samples during post-monsoon season and the highest during pre-monsoon season (Cu: 0.030±0.001μg/L in pre-monsoon and 0.026±0.002μg/L in post-monsoon, Zn: 0.087±0.003μg/L in pre-monsoon and 0.073±0.002μg/L in post-monsoon, Fe: 0.080±0.001μg/L in pre-monsoon and 0.055±0.001μg/L in post-monsoon). In contrast, metal concentration in surface sediment samples were higher in post-monsoon than in pre-monsoon season i.e. Cr 11mg/kg in pre-monsoon and 12mg/kg in post-monsoon, Mn 571mg/kg in pre-monsoon and 606mg/kg in post-monsoon, As (8mg/kg in pre-monsoon and 10mg/kg in post-monsoon, Pb (22mg/kg in pre-monsoon and 24mg/kg in post-monsoon, and Fe 2317mg/kg in pre-monsoon and 2435mg/kg in post-monsoon. We found a spatial gradient of high to medium to low in trace metal concentration from river to river mouth to offshore area. Considering the sources of metals, land erosion by waves and tidal action, an influx of water and sediment from the surrounding rivers, agricultural waste, industrial effluent and sewage are the most likely sources of metal pollution in the study area. We conclude that proper management strategies should be adopted to control the pollution and conserve the ecosystem health.

The spatial and seasonal variation of trace metals in coastal seawater and soft tissue of Chthamalus montagui around the northwest coast of Portugal

Metal concentrations (Cd, Cr, Cu, Fe, Mn and Zn) were determined in seawaters and soft tissues of Chthamalus montagui from the northwest coast of Portugal during the four seasons of 2011. The main objectives of this work were to assess seasonal and spatial variations of metals in order to detect hot spots of contamination, to establish correlations between metals in coastal seawaters and C. montagui and to calculate metal bioaccumulation factors (BAFs) in each season. Metal concentrations in coastal seawaters ranged within Cd: 1.2–35 ng L-1; Cr: 15–87 ng L-1; Mn: 77–1763 ng L-1; Cu: 126–1819 ng L-1; Fe: 430–4048 ng L-1 and Zn: 2889–16867 ng L-1 and in C. montagui ranged for Cd: 0.39–1.98 mg kg-1; Cr: 0.45–3.13 mg kg-1; Cu: 0.93–5.70 mg kg-1; Mn: 2.2–20.4 mg kg-1; Fe: 135–707 mg kg-1 and Zn: 119–782 mg kg-1. Significant spatial and seasonal variations were found between: (i) metal concentrations in seawaters and C. montagui tissues; (ii) the distribution of metal concentrations in C. montagui tissues were Fe > Zn > Mn > Cu > Cr > Cd and (iii) C. montagui showed higher bioaccumulation factors for Fe and Cd than for Cu, Mn and Zn in all seasons. Regarding the metal concentrations accumulated in C. montagui tissues during each season of 2011, the ecological quality classifications of the NW coast of Portugal varied from “Class I–Unpolluted” to “Class III–Remarkably Polluted”.

Spatial and Seasonal Trend of Trace Metals and Ecological Risk Assessment along Kanyakumari Coastal Sediments, Southern India

The concentration of selected trace metals (Fe, Cd, Cu, Pb, and Zn) in 30surface sediments were measured using Atomic Absorption Spectrometer to investigatethe spatial and seasonal variations of trace metals along Kanyakumari coast, India. Toassess the environmental risk of trace metals, enrichment factor, geo-accumulation index,pollution load index, and ecological risk index have been calculated. According to thepollution load index and geo-accumulation index (Igeo) values, Kanyakumari coastalsediments were unpolluted by Fe, Cu, Pb, and Zn, whereas moderately polluted by Cdwith low to moderate ecological risk. The existence of the high hydrodynamic conditionduring the southwest monsoon is more favorable to the transport of sediments andenhance the accumulation of metals, whereas during the northeast monsoon theaccumulation of metals is less. The baseline data for spatial distribution and seasonalvariation of trace metals and their controlling factors found in this study will be useful forpollution monitoring program along the Kanyakumari coast.

Trace metals dynamics under contrasted land uses: contribution of statistical, isotopic, and EXAFS approaches.

Three sub-basins of the Seine River (France) under contrasted land uses (i.e., forested, agricultural, and urban) have been investigated in order to assess the origin and seasonal variation of trace metals, and evaluate their geochemical background and dynamics. Our results highlight a high anthropogenic impact on all elements for both the dissolved and particulate fractions. The main source for each element in the dissolved phase was determined and shows that transition and post-transition metals mainly originate from forested areas, while alkali and alkaline earth elements, metalloids, and halogens rather originate from agricultural land use. Conversely, for the particulate phase, most of the elements cannot be associated with a specific land use. Seasonal variation of elements was assessed according to the forested and agricultural land uses, and geochemical backgrounds were determined using average export rates, highlighting that the geochemical background for the forested land use is higher than the agricultural one for most of the elements. Finally, to confirm those results, Zn dynamics in the three characteristic sub-basins and between the different land uses was investigated using a combination of Zn speciation, Zn isotopic ratio, and Zn export rates.

Seasonal variation and sources of dissolved trace metals in Maó Harbour, Minorca Island

The environmental conditions of semi-enclosed coastal water-bodies are directly related to the catchment, human activities, and oceanographic setting in which they are located. As a result of low tidal forcing, and generally weak currents, waters in Mediterranean harbours are poorly renewed, leading to quality deterioration. Here, we characterise the seasonal variation of trace metals (i.e. Co, Cd, Cu, Fe, Mo, Ni, Pb, and Zn) in surface waters, and trace metal content in sediments from Maó Harbour, a semi-enclosed coastal ecosystem in the NW Mediterranean Sea. Our results show that most of the dissolved trace metals in the waters of Maó Harbour exhibit a marked inner-outer concentration gradient, suggesting a permanent input into the inner part of the harbour. In general, metal concentrations in the waters of Maó Harbour are higher than those in offshore waters. Concentration of Cu (21±8nM), Fe (9.2±3.2nM) and Pb (1.3±0.4nM) are particularly high when compared with other coastal areas of the Mediterranean Sea. The concentration of some metals such as Cu and Zn increases during summertime, when the human population and boat traffic increase during the tourism season, and when resuspension from the metal enriched sediments is higher. The evaluation of the metal sources in the harbour reveals that, compared with other putative sources such as runoff, aerosol deposition and fresh groundwater discharges, contaminated sediments are the main source of the metals found in the water column, most likely through vessel-driven resuspension events. This study contributes to the understanding of the processes that control the occurrence and distribution of trace metals in Maó Harbour, thus aiding in the effective management of the harbour, and enhancing the overall quality of the seawater ecosystem.

Seasonal variations of trace metals of Eastern Black Sea streams of Turkey: a case study of Firtina, İkizdere

Seasonal variations of trace metals of Eastern Black Sea streams of Turkey: a case study of Firtina, İkizdere

Dynamic behaviour of trace metals in the Deûle River impacted by recurrent polluted sediment resuspensions: From diel to seasonal evolutions

An automatic trace metal monitoring station (ATMS) have been implemented in the river bank of the Deûle canal in the city of Auby (northern France), in the vicinity of metallurgical industries that have heavily polluted sediments, in Cd, Pb and Zn. Additionally, the fluvial traffic in this river is intense and surface sediments are resuspended several times per day. This paper is the following part of that published recently (Superville et al., 2014) in this journal. The main purpose of this paper is to present new information on diel and seasonal variations of trace metals in the Deûle River and highlight the potential role of sediments in the contamination of the water column. To this end, Cd, Zn and Pb were monitored at a high frequency (~1h−1) by voltammetry, distinguishing an electrolabile and an acid-leachable fraction. Our measurements revealed that (i) acid-leachable Cd is mainly bound to light particles such as clays and carbonates and its daily behaviour does not really depend on the intensity of sediment remobilisation process; (ii) acid-leachable Pb and Zn exhibit some seasonal variations which are explained here, suggesting they should at least partly depend on the ageing of hydrous ferric oxides in the sediments; (iii) in spring, the electrolability of Zn increases in agreement with the biological activity that may break some strong association between Zn and ligands and/or particles (e.g., organic matter, hydrous ferric oxides, etc.). This trend is observed for electrolabile Pb later in summer, but on a smaller scale since this metal is generally more strongly scavenged and less labile than Zn; and (iv) electrolabile Mn concentrations increase during the day due to desorption process of resuspended sediment particles in the water.

Assessment of antioxidant responses and trace metal accumulation by digestive gland of ribbed mussel Aulacomya atra atra from Northern Patagonia

Seasonal and spatial variability of trace metal concentrations and of a battery of antioxidant parameters were evaluated in digestive gland of the ribbed mussel Aulacomya atra atra. Fe, Al and Cu accumulated in tissue exhibited maximum values in winter, coinciding partially with the highest labile concentrations of Fe and Cu in sediment. Metals, as other pollutants, are known to influence the oxidative status of organisms and antioxidant enzymes have been often proposed as biomarkers of contaminant effects. Seasonal variations of trace metals did not appear to influence those of biochemical parameters, which generally showed an opposite trend with higher enzymatic activities in summer when trace metal concentrations were lower. Organisms from Punta Cuevas (control site) showed higher induction of reactive oxygen species production than those from both considered impacted sites, suggesting the possibility of some biochemical adaptation in organisms or a higher modulation of environmental and physiological factors on antioxidant responses than levels of trace metals. This study, which is the first in the area in this matter, showed that seasonal variations of potential biomarkers should be incorporated into interpretation of long-term biomonitoring studies in this marine coastal ecosystem.

Seasonal Variation of Metals in Seawater, Sediment, and Manila Clam Ruditapes philippinarum from China

Concentrations of trace metals (Cu, Pb, Zn, Cd, Cr, Hg, and As) were determined for the first time in seawater, sediment, and Manila clam from Deer Island, Liaoning Province, China. The seawater, sediment, and clam samples were collected seasonally at three clam farming sites around Deer Island during 2010-2011. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg, and As in the seawater samples were 4.16, 0.72, 5.88, 0.45, 2.51, 0.03, and 1.02μg/l, respectively. The seasonal variations of trace metals in seawater showed a significant difference in the concentrations of Cu, Pb, Zn, Hg, and As among seasons. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg, and As in the sediment samples were 6.43, 13.80, 53.08, 1.10, 36.40, 0.05, and 4.78mg/kg dry weight, respectively. Trace metal concentrations in sediment seasonally varied significantly except for Cd and Hg. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg, and As in the clam samples were 11.28, 0.61, 92.50, 0.58, 3.98, 0.03, and 1.98mg/kg dry weight, respectively. Concentrations of Cu, Zn, Cd, Cr, and As in Manila clam showed marked seasonal fluctuations with significant difference. Cu and Zn were the metals with the highest mean biosediment accumulation factor values in Manila clam. Besides, significant correlations for the concentrations of Cu and Zn relative to their concentrations in sediment were also found. Such differences in regression analyzes may be explained by differential bioaccumulation of essential and xenobiotic metals. Concentrations of trace metals in Manila clam did not exceed the maximum established regulatory concentrations for human consumption. Moreover, the calculations revealed that the estimated daily intake values for the examined clam samples were below the internationally accepted dietary guidelines and the calculated hazard quotient values were well less than 1, thus strongly indicating that health risk associated with the intake studied metals through the consumption of Manila clam from Deer Island was absent.

Seasonal variations of trace metals in clam (Meretrix casta) at Tharangampadi and vanjur Estuaries,Southeast coast of india

Seasonal variations of trace metals in clam (Meretrix casta) at Tharangampadi and vanjur Estuaries,Southeast coast of india

Annual and Seasonal Variations of Trace Metals in Atmospheric Suspended Particulate Matter in Islamabad, Pakistan

Total Suspended particulate matter (TSP) in urban atmosphere of Islamabad was collected using a high volume sampling technique for a period of one year. The nitric acid–perchloric acid extraction method was used and the metal contents were estimated by atomic absorption spectrophotometer. The highest mean concentration was found for Ca at 4.531 µg/m3, followed by Na (3.905 µg/m3), Fe (2.464 µg/m3), Zn (2.311 µg/m3), K (2.086 µg/m3), Mg (0.962 µg/m3), Cu (0.306 µg/m3), Sb (0.157 µg/m3), Pb (0.144 µg/m3) and Sr (0.101 µg/m3). On an average basis, the decreasing metal concentration trend was: Ca > Na > Fe > Zn > K > Mg > Cu > Sb > Pb > Sr > Mn > Co > Ni > Cr > Li > Cd ≈ Ag. The TSP levels varied from a minimum of 41.8 to a maximum of 977 µg/m3, with a mean value of 164 µg/m3, which was found to be higher than WHO primary and secondary standards. The correlation study revealed very strong correlations (r > 0.71) between Fe–Mn, Sb–Co, Na–K, Mn–Mg, Pb–Cd and Sb–Sr. Among the meteorological parameters, temperature, wind speed and pan evaporation were found to be positively correlated with TSP, Ca, Fe, K, Mg, Mn and Ag, whereas, they exhibited negative relationships with relative humidity. On the other hand, Pb, Sb, Zn, Co, Cd and Li revealed significant positive correlations with relative humidity and negative with temperature, wind speed and pan evaporation. The major sources of airborne trace metals identified with the help of principle component analysis and cluster analysis were industrial emissions, automobile exhaust, biomass burning, oil combustion, fugitive emissions, resuspended soil dust and earth crust. The TSP and selected metals were also studied for seasonal variations, which showed that Na, K, Zn, Cu, Pb, Sb, Sr, Co and Cd peaked during the winter and remained lowest during the summer, while Ca, Fe, Mg and Mn were recorded highest during the spring.

Distribution and seasonal variation of trace metals in surface sediments of the Mandovi estuary, west coast of India

The concentration and distribution of selected trace metals in surface sediments of the Mandovi estuary were studied to determine the extent of anthropogenic inputs from mining activities and to estimate the effects of the monsoon on geochemical processes in this tropical estuarine system. Analysis of bulk sediments from the Mandovi estuary shows that the concentrations of iron, manganese, cobalt, copper, zinc and lead vary from 2.2 to 49.7%; <Detection Limit (DL)–1.61%; 2.5–45.3 μg g −1; 11.5–77.5 μg g −1; 19.9–83.5 μg g −1; and 4.5–46.5 μg g −1, respectively. An important observation is that, in general, lowest metal concentrations are found during the monsoon, compared to the pre- and post-monsoon. Comparison of the metal levels in the sediments from different areas of the estuary indicates that there is a detectable anthropogenic input to the Mandovi estuary. The enrichment of Fe and Mn reflects the intensity of anthropogenic inputs related to iron ore processing in the upstream region of the estuary, however, the highest enrichment levels were not found near the mouth region. I geo values calculated for Fe (2.5) and Mn (3.4) showed higher values in the pre-monsoon period in the upstream region of the estuary than in the post-monsoon and monsoon seasons. Cu and Zn enrichment in the river mouth region, associated with high organic carbon contents, is indicative of the influence of organic wastes from municipal sewage entering the estuary. The intermetallic relationship revealed the identical behaviour of metals during its transport in the estuarine environment.

Special and seasonal variations of trace metals in PM10 in Chongqing

Nineteen trace metals in PM10 were measured by X-ray fluorescence spectroscopy (XRF) at three sites in Chongqing. The special and seasonal variations of trace metals in PM10 samples collected in the downtown were different from those in the background area of Jinyunshan. The source identification indicated that particulate materials were contributed mainly by two sources.

Trace metals and antioxidant enzymes in gills and digestive gland of the Mediterranean mussel Mytilus galloprovincialis.

A seasonal variability of trace metal concentrations and antioxidant enzymes was observed in gills and digestive gland of the Mediterranean mussel Mytilus galloprovincialis from both a polluted and a nonpolluted population. Trace metals (As, Cu, Fe, Mn, Pb, and Zn) exhibited, in both organs, maximum values in later winter-early spring followed by a progressive decrease during the summer. While in the gills this behavior probably reflects a different bioavailability of metals, in the digestive gland it is influenced mainly by the progressive infiltration of the organ by gonadic tissues during gametogenesis. Metals, as other pollutants, are known to influence the oxidative status of these organisms and antioxidant enzymes have been often proposed as biomarkers of exposure to contaminants. In this respect, it was of interest to compare the variations of these biochemical parameters with those of metal levels in two mussel populations from a polluted and a nonpolluted site, respectively. The biochemical parameters examined included the level of glutathione and the activity of the following glutathione dependent and antioxidant enzymes: glyoxalase I, EC 4.4.1.5; glyoxalase II, EC3.1.2.6; glutathione S-transferases, EC 2.5.1.18; glutathione reductase, EC 1.6.4.2; Se-dependent, EC 1.11.1.9 and Se-independent, EC 2.5.1.18 glutathione peroxidases; catalase, EC 1. 11.1.6; superoxide dismutase, EC 1.15.1.1. Seasonal variations of trace metals did not appear to influence those of biochemical parameters, which generally showed an opposite trend with higher enzymatic activities in summer when trace metal concentrations were lower. The effects of metals on antioxidant enzymes were more evident when the two mussel populations were compared. In particular, organisms from the polluted site showed lower levels of glutathione and higher enzymatic activities of glyoxalase I even though the magnitude of these differences was not constant during the year. Moreover, native mussels from both the polluted and control populations exhibited limited differences in the activities of glutathione reductase, glutathione peroxidases, catalase, and superoxide dismutase, suggesting the possibility of some biochemical adaptation in organisms from chronically polluted environments.

Limnological studies on the Nozha Hydrodrome, Egypt, with special reference to the problems of pollution

Water samples were collected in the different seasons during the period 1979–1981 from the Nozha Hydrodrome, Egypt, a small shallow lake receiving polluted Nile water, to gain information on the environmental conditions, nutrient contents, levels of trace metals and their possible variations in relation to pollution effects. The accumulation of trace metals in the lake sediments and in different tissues of the common fish, Tilapia species, was also investigated. During the study period, values for each of the parameters investigated generally gave a wide range of variability. The highest seasonal average air and water temperatures were recorded in July and the lowest values in January; the water temperature usually followed the pattern of the air temperature. The maximum seasonal average chlorosity in July is due to an increase in the rate of evaporation. The highest seasonal average for dissolved oxygen (DO) in January coincided mainly with a decrease in the rate of oxygen consumption associated with a drop in temperature and the continual mixing of the lake by wind action. The minimum regional averages of Secchi disc and chlorosity, as well as the lower regional average values of pH and DO in the supply canal reflect the turbidity and nature of the polluted feed Nile water. The seasonal changes of nutrients in the Hydrodrome are mostly influenced by their allochthonous input, and their main source is the supply of polluted Nile water, which first affects the inlet region. The high concentrations of inorganic nitrogenous and phosphate salts in the feed water are due to the discharge of untreated sewage and industrial wastes, as well as agricultural run-off into the water source of the Hydrodrome (Mahmoudia Canal). The nitrite produced in the lake is principally from nitrification of ammonia. The autochthonous supply of nitrate and phosphate is mainly from the decay of phytoplankton and subsequent release from lake sediments. The increase in silicate coincided principally with dissolution of diatom frustules. It appears that phytoplankton represents the main factor responsible for decreasing the concentrations of nutrients in the Hydrodrome. The seasonal variations of trace metals in the Hydrodrome are attributed to both external and internal effects. The former reflects the impact of man on the water source of the Hydrodrome, whereas the latter represents the events which occur within this lake. The data suggest a direct relationship between the concentrations of metals in the lake water and their concentrations in Tilapia fish. The data illustrate the ability of fish to absorb high levels of heavy metals and the ability of the lake sediments to accumulate these metals relative to those found in the lake water and the fish. In general, iron showed the highest mean values in the lake water, sediments and fish, whereas cadmium was present in the lowest concentrations. Comparison between the annual average value of each parameter in the present study and the corresponding value for the study of the heavily polluted Lake Mariut during the same period, as well as the comparison between the annual averages of nutrients and trace metals in the Hydrodrome and those in the predominantly clean Damietta branch of the Nile, provided evidence for the amount of pollution occurring in the study area.

Regional and seasonal variations of trace metals in tropical phaeophyceae from North Queensland

The brown algae Padina tenuis and P. tetrastromatica were selected as indicator organisms to monitor levels of ten metals (Fe, Cu, Co, Cd, Ni, Cr, Ag, Pb, Mn, Zn) in seawater from stations within Halifax Bay, Cleveland Bay, and Bowling Green Bay, near Townsville, on the northeast coast of Australia. Samples were collected monthly for one year to determine regional and seasonal variations of metal concentrations. The Highest Cu, Pb and Zn concentrations in algae were found at the Townsville Harbour station in Cleveland Bay. However, seawater samples from the Harbour and Bowling Green Bay showed significantly higher levels only for Zn in the Harbour waters. Furthermore, levels of dissolved Cd and Mn did not differ significantly between the two stations whereas levels of both metals were significantly lower in algae from the Harbour. It was concluded that the availabilities of, at least, Cd, Pb and Mn to algae were not readily identified by the techniques employed. Location-dependent variability was observed regarding correlations between metal pairs in algae and in those metals which were significantly correlated with temperature and salinity changes.