Patterns Of Metal Concentrations Research Articles

Quantification of regulated metals in recycled post-consumer polypropylene through comparative ICP-MS, AAS and LIBS analyses

Knowing the exact heavy metal load of recycled plastics is important for their risk assessment. We therefore established a novel strategic hierarchy for testing the heavy metal load of recycled plastics. For preliminary screening for unusually high elemental loads, laser-induced breakdown spectroscopy (LIBS) is suggested, while inductively coupled plasma-mass spectrometry (ICP-MS) or electrothermal atomic absorption spectroscopy (ETAAS) are used for exact quantification. The contents of ten regulated elements (Hg, As, Cd, Cr, Co, Cu, Se, Pb, Sn and Ni) in post-consumer (PCR), post-industrial (PIR), and virgin polypropylene (PP) were thus determined. Concentrations in the PCR were mostly found to be two orders of magnitude smaller than their threshold in non-food applications. Cu was most abundant in PCR with 18.7 ± 6.1 mg/kg. Concentration variations of approx. 30 %. were found within a PCR batch, while between batches, slightly higher variations of 30–40 % were observed. Moreover, the heavy metal concentration patterns of PCR and PIR differ significantly. This strategy may enhance the applicational possibilities for PCR.

Assessment of metals and metalloids agglutinated to airborne suspended particulate matter in selected plant species during the pre-and post-monsoon in the urban area

The elemental accumulation has emerged as a major environmental concern due to various anthropogenic sources such as vehicles, road dust, and industrial activities, contributing to the agglutination of elements to airborne Suspended Particulate Matter (SPM). SPM-bound elements accumulate on plant surfaces impact air quality and human health due to their noxiousness. Therefore, plants' ability to capture and mitigate air pollutants plays a crucial role in urban areas. This study aimed to investigate the levels and distribution of twenty-six elements, comprised of heavy metals (Cd, Pb, Cr, Cu Zn, Co, Ni, Fe, Mn, Ag, Mo, V, Ga, and Bi), light metals (B, As, Te, and Se), and metalloids (Al, Li, Sr, K, Mg, Na, Ca, and Ba) accumulated on the surface and inside the leaves of dominant plant species during the pre-and post-monsoon at six categorized (commercial, traffic-prone, residential, educational, greenbelt and industrial areas) locations in Delhi, India. In addition, the Metal Accumulation Index (MAI) was determined, and the statistical analysis was conducted using two-way ANOVA, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA). In the pre-and post-monsoon, two-way ANOVA revealed significant differences (P < 0.05) in metal concentrations. During the pre-monsoon plants exhibited the highest metal accumulation (∼21%) at the Anand Vihar (commercial) in Delhi, with the maximum average concentrations of Cr (118.25 mg/kg), Cu (204.38 mg/kg), Zn (293.27 mg/kg), and Fe (2721.17 mg/kg). Ficus benghalensis L exhibited the maximum 213.73 MAI at the Anand Vihar in the pre-monsoon. Ni and Cr indicated the highest correlation (P < 0.05, r = 0.82) in the PCA test. HCA test revealed similarity (∼87.7%) at ITO (traffic-prone) and Okhla Phase-2 (industrial) in F. religiosa regarding metal concentration patterns. Findings highlighted seasonal elemental pollutants uptake dynamics of plant species and explored species-specific metal accumulation, revealing potential implications of metal-tolerant plants for urban greenbelt.

TRANSFER OF HEAVY METALS IN SOIL IN-PLUM CULTIVATION: A FIELD STUDY IN ADAMACHI IASI, ROMANIA

Currently, global environmental concerns about heavy metal pollution are driven by rapid urbanization and industrial development. Therefore, a field study was conducted to assess the concentration of heavy metals (Pb, Co, Zn, Ni and Cu) in orchard soils and its transfer to two plum varieties (Stanley and Anna Späth) at Adamachi Farm – Iasi University of Life Sciences (IULS). In addition, heavy metal transfer (MTF), daily metals intake (DIM) and the index of health risk (HRI) were evaluated. The concentration of Pb, Co, Zn, Ni and Cu in soil and plum leaves samples were analyzed using atomic absorption spectrometry after acid digestion with a mixture of HNO3 (65%), HCl (37%) and HClO4 (60%). Metal concentration patterns occurred as follows 130.65&gt;76.6&gt;30.36&gt; 21.69&gt;13.26 mg/kg for Cu, Zn, Ni, Pb and Co in soil samples and 20.16&gt;10.00&gt; 2.10&gt;1.68 mg/kg for Zn, Cu, Ni and Pb in plum leaves, while Co residue was not detected. The maximum heavy metal concentrations were found at the soil surface (0 – 30 cm depth) due to soil organo-mineral content and antifungal treatments. The health risk index predicted (HRI) for adults as well as children was in the sequence Pb &gt; Cu &gt; Ni &gt; Zn, suggesting no health risk with values that did not exceed the safe limit (1). Therefore, it is essential to manage the causes and sources of heavy metal transfer prudently and effectively in order to prevent environmental contamination.

Intra- and inter-annual variations in metal concentrations in the superficial water of a highly polluted urban basin of Argentina.

To protect ecosystems impacted by human activities and prevent their degradation, it is imperative to evaluate variations in the concentration of environmental pollutants over time. Here, we evaluated the intra- and inter-annual variations of several metals from 15 sites in the Matanza Riachuelo River basin (one of the most polluted in the world) and determined the physicochemical and meteorological parameters associated with these changes from 2008 to 2015. For this, in each site, we used Asymmetric Eigenvector Maps and Redundancy Analysis. The results highlighted temporal patterns of metal concentrations and several factors associated with them, perhaps related to the actions performed in the area since 2008. Additionally, we found that the effects of physicochemical and meteorological factors on metal concentrations were site-dependent, possibly related to the presence of different local sources of pollution or characteristics of the river in each site, such as its sediments. This approach could be applied to different scenarios (aquatic and terrestrial) and could provide a tool to help decision-makers address the harmful consequences of the continuous advance of human activities on human and ecosystem health.

Trace elements in stomach oil of Scopoli's shearwater (Calonectris diomedea) from Linosa's colony

Calonectris diomedea is a colonial Procellariiform breeding on Mediterranean islands. The stomach oil produced during chick rearing is a peculiar trait of this species. The composition of the stomach oil is likely to reflect the composition of the prey ingested and might reveal the contaminants uptake with prey becoming a possible tool for the marine pollution monitoring. We examined the concentration of 15 trace elements by ICP-MS and direct mercury analyser. The principal component analysis revealed a heterogeneous pattern of metal concentration, showing a significant separation between samples collected 20 and 70 days after hatching. The data obtained in this work give preliminary information on the feeding habits and breeding ecology of Linosa's colony of Scopoli's shearwater. The trace metals variability found suggest that the stomach oil may have a role as trophic markers to understand predator-prey relationships and to have evidence on the accumulation of pollutants in the latter.

Heavy Metals in Marsh Clam (Polymesoda expansa) as Bioindicators for Pollution in Industrial and Sand Mining Area of Kelantan River Basin, Malaysia

Industrial and sand mining activities have severely degraded the water quality of the Kelantan River, as well as the river ecosystem. However, there have been inadequate studies on the effect of industrial and sand mining on organisms in the Kelantan River. Therefore, this study assessed the concentrations of Pb, Cd, Zn and Cu in the bivalves of genus (Polymesoda expansa) marsh clams from the Kelantan River tributaries, namely the Geting River and the Semarak River, which are located near to an industrial and a sand mining area, respectively. More than 50 marsh clams were collected at these sites. Heavy metals in marsh clams were extracted using aqua regia methods and analyzed using a Flame Atomic Absorption Spectrometer (FAAS). The mean concentrations of Pb, Cd, Zn and Cu at the Semarak River were 4.61, 2.16, 194 and 6.20 mg/kg, respectively. Accordingly, the concentrations at the Geting River were 4.43, 2.50, 196 and 7.90 mg/kg, respectively. The pattern of metal concentrations within the whole tissue of marsh clams from the Geting River and the Semarak River were in the following order: Zn &gt; Cu &gt; Pb &gt; Cd (concentration in mg/kg). The mean concentration of selected metals (Zn, Cd, Pb) in the studied samples exceeded the permissible limit set by the Malaysia Food Safety and Food Regulation 1985, the Food and Agricultural Organization, the World Health Organization, the Ministry of Health Thailand, and the Food and Drug Administration of United States (USFDA). Therefore, continuous monitoring of these bioindicators is essential to minimize the increasing health risk for aquatic life, as well as in food sources for human consumption, in the Kelantan River Basin. HIGHLIGHTS Heavy metals in Marsh Clam (Polymesoda expansa) tissues shows higher concentration in the small and medium sizes compare to big size The concentration of heavy metals (Zn, Cd and Pb) in Marsh Clam (Polymesoda expansa) tissues have exceeded the permissible limit set by Food and Drug Administration of United States (USFDA) and Malaysia Food Safety and Food Regulation Monitoring of heavy metals in aquatic organisms especially near to industrial and sand mining areas should be conducted regularly to reduce the risk to human health GRAPHICAL ABSTRACT

Epigenetic responses in juvenile Lemon sharks (Negaprion brevirostris) during a coastal dredging episode in Bimini, Bahamas

Sharks serve as key predators in coastal areas, with several species using near shore habitats as nursery refuges. With many shark species threatened or endangered, it is now critical to increase the knowledge of how anthropogenic activities impact these populations. This study is the first attempt at characterizing epigenetic modifications in elasmobranchs, and their potential as biomarkers of stress and disease using a dredging event episode in the early 2000′s in Bimini, Bahamas, as a model system. Lemon shark fin samples were selected from a historic archive (1995–2012) of Bimini’s North (impacted) and South (control) shark nurseries, and classified as before (1995–2000), during (2001–2006), and after (2007–2012) the dredging event. Genome-wide DNA methylation was analyzed in these samples, along with the quantification of trace metals to investigate temporal and spatial patterns of metal concentrations. The obtained results revealed differential DNA methylation patterns in sharks from the North nursery (closest to the dredging site). While low concentrations of metals were found for all nursery sites and time frames, one trace metal (Manganese) was significantly correlated with the observed differences in DNA methylation. Overall, the findings of this study support DNA methylation as a potential stress biomarker for sharks, even in the absence of a reference genome. Furthermore, the identification of genomic regions differentially methylated in response to stress provides a basis for future analyses aimed at identifying gene networks and subsequent physiological responses to these events. Collectively, these analyses will help improve shark population monitoring, management, and conservation in impacted areas.

Cycling of W and Mo species in natural sulfidic waters and their sorption mechanisms on MnO2 and implications for paired W and Mo records as a redox proxy

Redox-sensitive trace metal concentration patterns have been widely used to track redox conditions in aquatic environments. Among redox-sensitive trace metals, molybdenum (Mo) is of interest owing to its speciation behavior and associated changes in particle reactivity that cause significant changes in concentration patterns in oxic versus sulfidic conditions. However, current understanding of how to use Mo geochemistry of marine sediments as a paleoredox proxy is limited to determining presence or absence of, and in some cases the aerial extent of, sulfidic conditions in the past. Here, we present a combination work of field sampling analysis and experiments to link concentration patterns of another redox-sensitive trace metal, tungsten (W), to Mo in order to provide a framework for using these trace metals to track changes in sulfidic conditions in ancient aquatic environments. We analyzed W and Mo concentrations in the water column and sediment pore waters of the Chesapeake Bay. We found that dissolved Mo/W molar ratios varied under different redox conditions. Because concentrations of these trace metals are controlled by their speciation in solution, we defined three sulfidic zones based on W and Mo speciation and their impacts on particle reactivity: the weakly sulfidic zone (0.2 μM < [H2S] < ∼15 μM); the moderately sulfidic zone (∼15 μM < [H2S] < ∼600 μM); and the strongly sulfidic zone ([H2S] > ∼600 μM). In all sulfidic zones, dissolved W concentrations were positively correlated with dissolved Mn concentrations. In contrast, the dissolved Mo concentrations were negatively correlated with dissolved Mn concentrations. As a result, Mo/W molar ratios were negatively correlated with dissolved sulfide concentrations in the weakly, moderately, and strongly sulfidic zones. Our sorption experiment results indicate that the negative correlation between Mo/W molar ratios and dissolved oxygen concentrations in the oxic zone is likely due to the stronger adsorption of WO42– onto Mn oxide surfaces compared with that of MoO42–. In comparison, the negative correlation between Mo/W ratios and sulfide concentrations in sulfidic waters is attributed to the differences in thiolation processes of W and Mo, with Mo exhibiting a higher degree of thiolation than that of W. Because W and Mo speciation controls their particle reactivities, these results together indicate that both speciation of W and Mo and their particle reactivity with respect to solid phases control the behaviors of Mo/W molar ratios in various reducing environments. Our results also suggest that in both oxic and weakly sulfidic conditions, both WO42– and MoO42– dominate. In contrast, different thiolated anions of W and Mo are likely to be present in the sedimentary records deposited in sulfidic systems. Thus, the results suggest that the dissolved Mo/W molar ratio combined with their speciation information is a strong indicator of redox changes (including oxic and sulfidic changes). Solid phase Mo/W molar ratios increase as sulfide levels increase and thus can be used to track variations in redox conditions (as well as the severity of sulfidic conditions) in ancient oceans.

Trace metal concentrations in soil-plant complex in rocky shore salt marshes of Central Patagonia

Population growth and industrialization involve environmental problems, such as metal pollution, and coastal environments are particularly susceptible to such issues. Within this framework, we aimed: (i) to determine the levels of trace metals in soils and Spartina densiflora tissues in rocky shore marshes of Central Patagonia; (ii) to relate metal concentration patterns in the different soil-plant complex fractions to environmental conditions; and (iii) to investigate whether geographical metal concentration patterns can be explained with anthropogenic influences and sources and/or by local prevailing biogeochemical processes. For this purpose, soil samples and associated vegetation were collected in five rocky shore marshes located at different distances from an urban or industrial area. The concentration of Al, Cd, Cr, Cu, Fe, Ni, Pb, and Zn in soils (pseudototal and bioavailable) and in plants (roots and shoots) was determined. Then the enrichment factor, bioaccumulation and translocation factor were calculated. The soil mineralogy and the behavior of these metals according to different soil variables were discussed. The results showed different behavior and level of anthropic impact according to the metal considered. Salt marshes located on the southern edge of the Nuevo Gulf showed the highest concentrations of metals. Fe, Al, Cu and Zn showed mostly a natural origin. Fe and Al were mainly in soils rather than in plants, while Cu and Zn were similarly distributed in both matrixes. Although Cd in soils showed enrichment, it would have a natural origin. Also, it was scarce in the soil and was mostly concentrated in Spartina’ roots. Pb, Cr and Ni showed anthropic enrichment too, being mainly derived from the port and industrial activities. Pb had significant representation in all soil-plant subsystems and showed the highest bioavailability in soils. Cr and Ni, were found in high concentration in the soil and showed a high bioaccumulation in roots. The human impact level in rocky shore marshes of the Nuevo Gulf in Central Patagonia associated to the trace metals pollution varies from being scarce to significantly important, with the marshes located in its southern margin showing the worst scenarios.

Drawing the baseline of trace element levels in the vulnerable Mediterranean osprey Pandion haliaetus: variations by breeding location, habitats, and egg components.

Due to its peculiarity to accumulate environmental contaminants, the osprey Pandion haliaetus is a sentinel species for the biomonitoring of contaminants in aquatic ecosystems. Despite this, no information on trace element concentration exists for the Mediterranean area, where relict and vulnerable osprey populations exist. We evaluated the geographical patterns of heavy metals and selenium in osprey eggs from three different populations of the Mediterranean basin (Balearic Islands, Corsica, and Tuscany), to identify any possible contaminant sources. Pattern of metal concentration followed the order: Fe > Zn > Cu > Se > Hg > Pb > Cd. Differences in contaminant concentrations between habitats and among egg components were found. Egg content and inner membrane showed higher mercury levels (1.06 ± 0.89 and 0.67 ± 0.62mg/kg dw, respectively) than those recorded in the eggshell. Mercury concentration was ca. two times higher in marine than in wetland samples, and even higher (3.6 times) when referred to the eggshell. Cu, Fe, Zn, and Se had higher concentration in the inner membrane. We stress how the choice of the biological material can have significant implications for the correct evaluation of contamination. Our study represents a first regional scale survey for the vulnerable Mediterranean osprey populations and provides baseline data for their long-term biomonitoring.

Modeling singular mineralization processes due to fluid pressure fluctuations

Mineralization in the Earth's crust can be regarded as a singular process resulting in large amounts of mass accumulation and element enrichment over short time or space scales. The elemental concentrations modeled by fractals and multifractals show self-similarity and scale-invariant properties. We take the view that fluid-pressure variations in response to earthquakes or fault rupture are primarily responsible for changes in solubility and trigger transient physical and chemical variations in ore-forming fluids that enhance the mineralization process. Based on this general concept, we investigated mineral precipitation processes driven by rapid fluid pressure reductions by coupling mineralization to a cellular automaton model to reveal the nonlinear mechanism of the orogenic gold mineralization process using simulation. In the model, fluid pressure can increase to the rock failure condition, which was set as lithostatic pressure at a depth of 10 km (270 MPa), due to either porosity reduction or dehydration reactions. Rapid drops in pressure resulting from fault rupture or local hydrofracture may induce repeated gold precipitation. The geochemical patterns generated by the model evolve from depletion to enrichment patterns, and from spatially random to spatially clustered structures quantified by multifractal models and geostatistics. Results show how metal elements self-organize to form high metal concentration patterns displaying self-similarity and scale-invariance. These transitions are attributed to the growth and coalescence of sub-networks with different fluid pressures up to the percolation threshold, resulting in a wide range of fluid pressure reductions and gold precipitation in the form of clusters. The results suggest that cyclic evolution of fluid pressure and its effects on gold precipitation systems can effectively mimic the repeated mineralization superposition process, and generate complex geochemical patterns characterized by a multifractal model. The nonlinear behavior exhibits scale-invariance and self-organized critical threshold, where mineral phase separations result from fluid pressure reductions associated with fault failure.

Interspecific Differentiation in Heavy Metals Concentration in Fishes of the Apa River, Upper Paraguay River Basin

Heavy metals concentration in fishes are important indicator geomorphological or environmental integrity in aquatic habitats. Aiming to evaluate metal concentration in fish muscles in Apa River, upper Paraguay basin, we analyzed 124 individuals of eight fish species at Cachoeira do Apa district (Porto Murtinho) from 2013 to 2014 belonging to Brycon hilarii , Leporinus friderici , Megaleporinus macrocephalus , Megaleporinus obtusidens , Piaractus mesopotamicus , Prochilodus lineatus , Pterodoras granulosus and Salminus brasiliensis . The samples were frozen and in the laboratory the musculature was removed, the samples were digested using the triacid method, and later the concentration of heavy metals was quantified in a flame atomic absorption spectrophotometer. There is a significant difference in the concentration of metals in fish (F=27.79, p<0.001). Considering the multivariate comparison o f studied species, we observed that P. lineatus have a more different pattern of metal concentration, with P. granulosus also presenting a different pattern of others species. None species presented the concentration of metals above the limit defined by Brazilian legislation, however, species differed in their metal concentrations according to the position in the water column and feeding, suggesting that the integrated assessment of the concentration of metals may be an indicator of ecological differences in the obtaining of resources by species in aquatic communities. DOI: http://dx.doi.org/10.17807/orbital.v10i1.1040

Bioaccumulation of trace metals in farmed pacific oysters Crassostrea gigas from SW Gulf of California coast, Mexico

The aim of the study was to evaluate the bioavailability of trace metals (Chromium, Copper, Nickel, Lead, Zinc, Cadmium, Arsenic, and Mercury) in the commercially consumed Crassostrea gigas oysters collected over a 12-month growth period (2011–12) from an experimental cultivation farm in La Pitahaya, Sinaloa State, Mexico. Sediment and water samples were also collected from four different zones adjacent to the cultivation area to identify the concentration patterns of metals. The results revealed that sewage disposals, fertilizers used for agricultural practices and shrimp culture are the major sources for the enrichment of certain toxic metals. The metal concentrations in oysters presented a decreasing order of abundance (all values in mg Kg−1): Zn (278.91 ± 93.03) > Cu (63.13 ± 31.72) > Cr (22.29 ± 30.23) > Cd (14.54 ± 4.28) > Ni (9.41 ± 11.33) > Pb (2.22 ± 1.33) > As (0.58 ± 0.91) > Hg (0.04 ± 0.06). Bioconcentration Factor (BCF) and Biota Sediment Accumulation Factor (BSAF) exhibited that C. gigas in the region are strong accumulators for Zn and Cd respectively. Thus, the present study proves to fulfill the gap in understanding the rate of bioaccumulation of metals in C. gigas which is regarded as the most sought after oyster species globally.

Exposure factors of cadmium for residents in an abandoned metal mine area in Korea

This study evaluated blood and urine cadmium (Cd) levels and human exposure factors for residents in an abandoned metal mine in Korea. We collected blood, urine, soil, water, and rice grain samples to analyze Cd concentrations and analyzed heavy metal concentration patterns in soil. We estimated the major exposure factor of Cd through non-carcinogenic risk assessment depending on exposure routes. The blood Cd concentration in the case group was 5.33 μg/L (geometric mean), significantly higher than that in the control group (1.63 μg/L, geometric mean). Urine Cd concentrations were also similar. The Cd concentrations in paddy soil (1.29 mg/kg) and rice grains (0.14 mg/kg) in the study area were higher than those in the control area (0.91 and 0.07 mg/kg, respectively). The analysis of heavy metal concentration in soil showed that the Cd levels in agricultural soil in the case group were attributable to the mine. The hazard quotient (HQ) of Cd by rice ingestion in the case group (1.25) was 2 times higher than that in the control group (0.6). We found that the HQ of rice ingestion contributed to more than 97 % of the total HQ, indicating that rice grains were the major exposure source. However, it is likely that the continuous intake of Cd-exposed crops led to chronic exposure among the residents in mine area.

Effects of combined sewer overflows and storm water drains on metal bioavailability in small urban streams (Prague metropolitan area, Czech Republic)

The aims of the study were to evaluate the effect of combined sewer overflows (CSO) and storm water drains (SWD) on metal bioavailability in small urban streams in Prague and to evaluate levels of metals in water, sediment, and macroinvertebrates. The following working hypotheses were adopted: (a) sites dominantly affected by SWD are less polluted by metals, and (b) sites dominantly affected by SWD have higher bioavailability of metals. Physical and chemical parameters (pH, conductivity, NO3-N, NH4-N, COD, alkalinity, and water hardness) and concentrations of the metals Cu, Zn, Pb, Ni, and Cr were determined in samples of water and sediment at five to six sites on four target streams—Zatisský Creek, Kosikovský Creek, Botic Creek, and Rokytka Creek—three to five times per year during the period 2002–2004. The sites from all studied creeks were categorized into five groups according to the prevailing type of urban drainage impact. Macroinvertebrates were sampled and analyzed for metals at each site for a period of 1 month. The concentration patterns of metals were interpreted by partition coefficient (Kd), hazard quotient (HQ), cumulative criterion unit (CCU), and biota sediment accumulation factor (BSAF). Concentrations of metals in water as well as in sediment at sites receiving water from SWD were lower than at sites where creeks receive water from CSO, except for Pb. Concentrations of Cu, Zn, and Pb in sediment were higher at sites affected by CSO. Concentrations of metals in aquatic macroinvertebrates, expressed as BSAF, indicated higher values at sites affected by SWD. Frequencies of high BSAF (>1) were lower in CSO compared to SWD. This finding was explained by (a) a decrease of pH on SWD sites compared to the increase of pH on CSO sites during rain events, (b) a greater resuspension of sediment at SWD sites during rain events, and (c) an abundance of organic matter in CSO available for sorption of metals and a corresponding reduction of their bioavailability. In the study area, the type of urban drainage affects the bioavailability of metals—while SWD increase metal bioavailability, CSO cause its decrease. The sediments in SWD sites do not indicate risk to the benthic community according to the applied environmental quality standards. Water and sediment in creeks affected by SWD are less polluted by metals. Both working hypotheses were therefore supported.

Bioaccumulation of metals in fish species from water and sediments in macrotidal Ennore creek, Chennai, SE coast of India: A metropolitan city effect

Accumulation of trace metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd) were investigated in water, sediment (n=20) along with six fish of diverse feeding guilds (Sillago sihama, Liza parsia, Etroplus suratensis, Oreochromis mossambicus, Arius parkii and Gerres oyena) from the Ennore creek, northern part of Chennai metropolitan megacity, southeast coast of India. Dissolved trace metals (DTMs) in surface water samples and total trace metals (TTMs) in surface sediments (top 0–10cm) indicate that concentration pattern of metals was higher in the discharge point of the river/channels entering the main creek. The maximum mean values of DTMs exhibited the following decreasing order (expressed in µg/L): Fe (1698)>Mn (24)>Zn (14.50)>Pb (13.89)>Ni (6.73)>Cu (3.53)>Co (3.04)>Cr (2.01) whereas the trend is somewhat different in sediments (µgg−1): Fe (4300)>Mn (640)>Cr (383)>Zn (155)>Cu (102)>Ni (35)>Pb (32)>Cd (0.51) are mainly due to the industrial complexes right on the banks of the river/channels. Species-specific heterogeneous patterns of tissue metal loads were apparent and the overall metal enrichment exhibited the following decreasing order (expressed in µgg−1): Cu (7.33)>Fe (6.53)>Zn (4.91)>Cr (1.67)>Pb (1.33)>Ni (0.44)>Mn (0.43)>Co (0.36)>Cd (0.11). This indicates that metals are absorbed onto the different organs, which is also endorsed by the calculated values of bioaccumulation factor (BAFs) (avg. muscle 117, gill 126, liver 123, intestine 118) in fishes. The high calculated biota sediment accumulation factor (BSAF) (0.437) for the species Arius parkii is considered to be a potential bioindicator in this region. The enrichment of trace metals is also supported by the association of metals in water, sediments and different body organs (muscle, gill, liver, intestine) of fish samples. Comparative studies with other coastal regions indicate considerable enrichment of DTMs & TTMs in sediments as well as in various organs of fish samples. Holistic spatial, temporal monitoring and comprehensive regional strategies are required to prevent health risks and ensure nutritional safety conditions.

Concentration profiles of metals in breast milk, drinking water, and soil: relationship between matrices.

The concentrations of Cd, Cr, Cu, Hg, Mn, Ni, Pb, Sn, and Zn were determined in breast milk of women living in Conceição das Alagoas, Minas Gerais, Brazil. The potential relationships between metal levels in samples of breast milk, drinking water, and soils collected in the study area were also established. Metal levels in breast milk, except Cr, were lower in comparison to WHO reference concentrations. Zinc was the predominant element in breast milk and drinking water samples, with a median level of 46.2 and 82.2 μg · L(-1), respectively. Soils presented a different pattern of metal concentrations with respect to those found in breast milk and drinking water, Chromium showed the highest median levels (148 mg · kg(-1)), while a certain predominance of Zn and Cu was also observed (47.0 and 43.0 mg · kg(-1), respectively). Similar profiles were observed when comparing metal concentrations in drinking water and breast milk (chi-square χ(2) = 14.36; p < 0.05). In contrast, breast milk-soil and drinking water-soil metal concentration profiles showed significant differences (χ(2) = 635.05 and χ(2) = 721.78, respectively; p < 0.05). These results indicate that drinking water is an important exposure pathway for metals to newborns through breast milk. Further studies should be aimed at assessing the body burdens of metals in that population and at evaluating the potential relationships in the concentrations in biological and environmental matrices as well as at estimating the contribution of dietary intake of metals. In addition, the presence of other chemical pollutants in breast milk should be also studied in order to assess the combined newborn exposure to other contaminants.

Variations of trace metals in two estuarine environments with contrasting pollution histories

In the present study, seasonal variations of metal concentrations were examined in two oyster species, Crassostrea hongkongensis and Crassostrea sikamea, and in seawater from a heavily contaminated estuary and a reference estuary. Strong temporal fluctuations of metal concentration were observed in oyster tissues as well as in seawater from both estuaries, especially for the contaminated estuary and for C. hongkongensis with higher accumulation ability. A closer inter-element correlation was observed for Cu, Zn, Cr and Ni in both the dissolved and particulate phases from the contaminated site, indicating that these metals originated from the same industrial sources. Seasonal variations of metals in oysters were not significantly related to their concentrations in seawater, but were related to the variations of condition index. Our results showed that the seasonal patterns of metal concentrations in oysters were largely controlled by the biological process, while the variation as well as the concentration were dependent on the contamination levels and bioaccumulation ability.

Social-Ecological Patterns of Soil Heavy Metals Based on a Self-Organizing Map (SOM): A Case Study in Beijing, China

The regional management of trace elements in soils requires understanding the interaction between the natural system and human socio-economic activities. In this study, a social-ecological patterns of heavy metals (SEPHM) approach was proposed to identify the heavy metal concentration patterns and processes in different ecoregions of Beijing (China) based on a self-organizing map (SOM). Potential ecological risk index (RI) values of Cr, Ni, Zn, Hg, Cu, As, Cd and Pb were calculated for 1,018 surface soil samples. These data were averaged in accordance with 253 communities and/or towns, and compared with demographic, agriculture structure, geomorphology, climate, land use/cover, and soil-forming parent material to discover the SEPHM. Multivariate statistical techniques were further applied to interpret the control factors of each SEPHM. SOM application clustered the 253 towns into nine groups on the map size of 12 × 7 plane (quantization error 1.809; topographic error, 0.0079). The distribution characteristics and Spearman rank correlation coefficients of RIs were strongly associated with the population density, vegetation index, industrial and mining land percent and road density. The RIs were relatively high in which towns in a highly urbanized area with large human population density exist, while low RIs occurred in mountainous and high vegetation cover areas. The resulting dataset identifies the SEPHM of Beijing and links the apparent results of RIs to driving factors, thus serving as an excellent data source to inform policy makers for legislative and land management actions.

Heavy metals in eggshells of cattle egret (Bubulcus ibis) and little egret (Egretta garzetta) from the Punjab province, Pakistan

Concentrations of nine trace metals were determined to assess site-specific and species-specific differences using Fast Sequential Atomic Absorption Spectrophotometer (Varian FAAS-240) in eggshells of Bubulcus ibis and Egretta garzetta from seven heronries in the Punjab province, Pakistan. Pattern of metal concentration followed the order: Fe>Zn>Pb>Mn>Cd>Cr>Li>Cu>Ni. Greater mean concentrations of Mn(1.17μg/g), Ni(0.11μg/g), Pb(1.49μg/g), Cd(0.88μg/g), Cr(0.7μg/g), Cu(0.20μg/g) and Li(0.27μg/g) were recorded in little egret. Mean concentrations of Mn, Pb, and Cr, (3.98, 5.4, 0.8μg/g) were significantly higher in eggshells collected from Shorkot; Cu, Zn and Ni (0.19, 13.0, 0.12μg/g) from the Trimu Headwork; Cd (1.23μg/g) from Jhang Faisalabad Road and Fe (67.98μg/g) from Mailsi. Multivariate analyses indicated that Mn, Pb, Cd, Ni, Cu, Cr and Zn were associated with anthropogenic activities and Fe and Li with natural origin. This study provides the baseline data for a monitoring program and revealed that egg-shells can serve as a bio-monitor of local metal contamination.