Metals In Shells Research Articles

Achieving high capacity by controlling the size of Fe/Co-N-C(t) in the cathode of lithium-oxygen batteries

Two samples are synthesized in a bimetallic system of iron and cobalt using a Metal-Organic Framework (MOF). The duration of precursor addition to the reaction vessel is controlled to synthesize Fe/Co-N-C(10 h) and Fe/Co-N-C(At once). The structural properties of the samples are analyzed using XRD, Raman, FT-IR, SEM, TEM, BET, TGA and ICP. Electrochemical tests are performed to evaluate the activity of the prepared catalysts as lithium-oxygen battery cathode materials. The Fe/Co-N-C(At once) sample, with its larger surface area, shows a greater discharge capacity of 8670 mAhg-1 compared to the Fe/Co-N-C(10 h) sample, which has a discharge capacity of 8339 mAhg-1. However, the Fe/Co-N-C(10 h) sample has a larger electrochemical active surface area due to the presence of more metals in the MOF shell. This results in higher ORR/OER activity in an alkaline environment and greater stability (180 h) as a lithium-oxygen battery cathode compared to the Fe/Co-N-C(At once) sample, which exhibits stability for 90 h.

Trophodynamics and health risk assessment of heavy metals in seafood from a tropical estuary in the gulf of Guinea

Seafood is an essential protein source for coastal communities. However, they can accumulate heavy metals from human activities which could pose a potential health risk to consumers. In this study, we investigated the distribution, bioaccumulation, trophic transfer and potential human health risk of heavy metals in sediments, shell and fin fish collected from the Escravos Estuary in southern Nigeria. Heavy metals (Ni, Cd, V, Pb and Cu) in sediments, periwinkles and tongue soles from the two study sites were lower than the permissible limits for fishery products. The metal distribution in fish tissues was in the decreasing order of liver > gills > muscles > gonads > rest of the fish. Moderate to high BSAF (>1) was reported for Cd, Pb and Cu. All the studied metals, except Pb, showed evidence of biomagnification from periwinkle to tongue sole. The estimated daily intake (EDI) and hazard ratio (HR) for metals in periwinkles from both study sites were lower or within the USEPA reference doses (RfD) for the respective daily intake and HR value < 1, except for Cd, V and Pb for children. In contrast, EDI values in the muscle of tongue soles were higher than the RfD values for heavy metals except for Ni and Pb, whereas HR values > 1 except for Ni, Cd and V. In the whole fish, EDI and HR values were disproportionately high in both study sites with higher values reported for children. This study provides the first insights on the trophic transfer and risk assessment of heavy metals from petroleum and gas operations impacting the Escravos Estuary and the implications to public health.

Seasonal and interannual variability of heavy metals and other microelements in wild and farmed mussels Mytilus galloprovincialis in Saldanha Bay (South Africa)

The temporal fluctuations of the levels of 21 of macro- and microelements including heavy metals in soft tissues and shells of mussels from waters of Saldanha Bay (South Africa) collected in the period of 2013–2019 were analyzed by using Neutron activation analysis. The wild and farmed sets of Mytilus galloprovincialis were selected from the bays with different hydrological conditions: from open ocean bay to the relatively closed site. It was concluded that the found features of elements’ distribution could be explained by hydrological regimes, influence of the coastal runoffs and mixing of waters, which led to higher levels of heavy metals and microelements. The farmed mussels demonstrated lower maxima for many elements during the study period but could show local increasing due to intense hydrological mixing with resuspending of bottom sediments and terrigenous runoff indicated by the non-volatile elements such as Sc, Cs, Th. The obtained data were not revealed high anthropogenic influence during studied period in comparison with the other water areas. The study proposed the indicative background levels for the heavy metals and other determined elements in the Saldanha Bay area based on the maximum values from the pristine water area obtained in the considered period.

Introducing Ce into the interface of NiCo LDH@PBAs to build multi core–shell electrode with superior stability of supercapacitor

Core-shell electrodes have been used in many fields, however, the poor conductivity caused by the weak interfacial interaction limits the practical application of the composites. Herein, a novel multi core–shell material (NiCo-Ce@PBAs) used as electrode in supercapacitor is prepared using Ce as bridge to connect the core (NiCo LDH) and shell (NiCo PBAs). Benefiting from the gradient orbital coupling of 2p-4f-π derived from O-Ce-C≡N unit sites in NiCo-Ce@PBAs, the composite shows enhanced covalency and determines to delocalize the electronic expansion in the interaction. Besides, the redox pair of Ce3+-Ce4+ also makes great contribution to expedite the charge transfer as well as enhancing the binding energies of metals in core and shell. Overall, the optimized core–shell electrodes show excellent electrochemical performance with high area-specific capacitance of 1847 F g−1 at 1 A g−1, which is much higher than that of LDH-based electrodes ever reported. In addition, the electrode is found better cyclic performance than the others (95.7 % even after 10,000 cycles), which is due to the fact that the special 4f empty orbits can store partial electrons, thus decreasing the polarization phenomenon. It also shows great practical application when using commercial activated carbon as cathode. This work illustrates a new strategy to construct core–shell electrodes with strong interfacial interaction as well as revealing the important role of orbital theory in the design of multi core–shell electrodes.

Data of bioaccumulation and biomagnification from soil in biota nettle-snail (Urtica dioica, L and Helix pomatia,L) of heavy metal (Pb, Zn, Ni) pollution of mining activity in Mitrovica.

ABSTRACT&#x0D; In this research project, we measured the impact and distribution of the activity of minning Trepça Complex in Mitrovica on the concentrations of heavy metals (Pb, Zn, Ni) in soil, plant (Urtica dioica,L) and shell of snail (Helix pomatia).&#x0D; Introdiction: Large quantities of these metals come from natural and anthropogenic sources including mining activity, agriculture, pesticide use, industrialization, and inadequate disposal of mineral waste and artificial fertilizers. These inorganic pollutants are deposited in the soil, water, and atmosphere in various forms of complexes and are thus transmitted from plants, animals to humans. Climatic factors such as winds, rains, and temperatures are believed to be major contributors to the spread over time and space of heavy metals in the environment.&#x0D; Materials and methods: Soil samples, nettle plant (Urtica dioica, L), and snail (Helix pomatia, L), were collected from the selected pollution source of mine Trepça complex at distances of 1km, 2km, and 5km in the radius circles divided into four geographical areas. Also the control samples are collected in unpolluted site Opoja-Dragash municipalty. The samples were digested in microwave at 2000C for 45 min and have been read in flame absorber Analyticjena Contra AAA.&#x0D; Results: Higher concentrations of Pb, Zn, and Ni were recorded in the southern parts of the country compared to that control with significant differences (p&lt;0.01). Bioaccumulation and biomagnification levels of these heavy metals have also been recorded in the roots, stalks, and leaves of the stinging nettle plant (Urtica dioica, L) as well as in snail shells (Helix pomatia, L.).&#x0D; Conclusions: The results show that the stinging nettle plant has translocated larger amounts of these heavy metals especially Pb along with the vegetative organs wherefrom these they are carried in the snail shell, which is fed on the stinging nettle plant.&#x0D; Also, results shown that the nettle plant Urtica dioica can be used in phytoremediation process whereas snail Helix pomatia can be used like bioindicator of heavy metal pollution.&#x0D; &#x0D;

Bioaccumulation of Heavy Metals in Water, Algae, Sediments, Egg Shells and Feathers of ANAS PLATYRHYNCHOS From River Swat and Barandu KP, Pakistan

The concentration of selected heavy metals in water, algal flora and sediments and their bioaccumulation in eggshells and feathers of Anas platyranchos were measured at target sites along River Swat and River Barandu in Khyber Pakhtunkhwa, Pakistan. The order of HMs in water and sediment samples at River Swat was Cd &gt; Zn &gt; Ni &gt; Cu &gt; Cr &gt; Pb and Zn &gt; Cd &gt; Ni &gt; Cu &gt; Cr &gt; Pb, respectively. While in River Barandu, it was Cu &gt; Cd &gt; Zn &gt; Ni &gt; Cr ≈ Pb and Cu &gt; Zn &gt; Cd &gt; Ni &gt; Pb &gt; Cr, respectively. The concentration of Cu, Zn, Ni, Cd and Pb was below the WHO permissible limits while the concentration of Cr exceeded the permissible limits in the water of River Swat, however, in River Barundu the selected HMs were under the safe limit. The target HMs in both rivers taken by A. plathyrnachos via water, sediments and food showed higher bio-concentration factor when compared to bio-sedimentation factor. Comparatively, River Swat was found to be more polluted than River Barundu for the selected HMs. The higher rate of bioaccumulation in the eggshells and feathers of A. platyranchos investigated in the present study can be considered a reliable biomarker to assess the biomagnification of pollutants in an aquatic food chain.

Concentration Analysis of Pb and Cd in Water and Blood Shells (Anadara granosa) in Rupat Strait Water

Water pollution occurs due to waste from various community activities that produce liquid, solid, and gas waste. One of the wastes produced is heavy metals that are harmful to organisms and humans. The research was conducted in December 2020-March 2021 in the Waters of Rupat Strait of Riau Province. This study aims to analyze the concentration of Pb and Cd metals in water and blood shells (Anadara granosa), know the relationship of Pb and Cd metal concentrations to morphometric blood shells (A. granosa), and know the relationship of Pb and Cd metal content in water and blood shells (A.granosa). The method used in the research is the survey method. The results showed that the concentration value of heavy metals in seawater in the Rupat Strait Waters (Cd 0.11mg/L), (Pb 0.86 mg/L). Concentrations of heavy metals in blood shells (A. granosa) in rupat strait waters ranged Cd (0.04 mg/kg), Pb (0.03-0.06 mg/kg). Based on these results, pb and cd metal in the sea pair in the strait has passed the quality standard set while the Metal Pb and Cd on blood shells are still below the quality standard which means it is still safe to be consumed

Shells of Pearlmussels, Margaritifera dahurica (Bivalvia: Margaritiferidae), as a biogeochemical indicator of the background (Holocene) and current major and trace elements content in riverine waters of Transbaikalia (southeast Siberia)

The concentration of the major and trace elements in the riverine waters of the Upper Amur basin (Transbaikalia, southeast Siberia) in the Late Holocene (5.5–1.2 kya) was determined by their accumulation in the archaeological shells of the Pearlmussel Margaritifera dahurica (Margaritiferidae, Bivalvia). A positive relationship between the accumulation of elements in the recent shells and their average long-term content in the aquatic environment was revealed. Based on the equations of the relationship between the accumulation of metals in the Pearlmussel shells from archaeological excavations, the content of each element in the aquatic paleoenvironments on the territory of the Upper Amur basin was calculated. We show that the current content of heavy metals in the river waters of this region is significantly increased compared with the same of Late Holocene, which indicates an increase in pollution of the aquatic environment by anthropogenic impact. The empirical relationship between the accumulation of metals in shells and their content in water adequately describes their accumulation in archaeological shells and living mollusks of the same species. The concentrations of the major and trace elements in archaeological shells of Margaritifera and their paleoenvironment may be accepted as background values for the rivers of the Upper Amur basin.

Analysis of Cadmium (Cd) and Lead (Pb) Heavy Metal Content in Shell and Mangroves at Bima Bay

This study aims to determine the levels of heavy metals (Cd) and (Pb) in shellfishes and mangroves at Bima bay. The results showed that bivalves and mangrove tissue were analyzed for heavy metal content in the form of lead (Pb), and Cadmium (Cd) using an Atomic Absorption Spectrophotometer. From tissue analysis, it indicates that the content of heavy metals lead (Pb) in 3 species of Shellfish which showed different results; Blood shells (Anadaragranosa) of 0.756 ppm, Hiatula shells (Hiatula chinensis) 1.59 ppm, and Shells (Siliqua winteriana) 1.171 ppm. Cadmium (Cd) metals in Shells are each found; Cockle shell (Anadara granosa) of 0.802 ppm, Hiatula shells (Hiatula chinensis) 0.334 ppm and Shells (Siliqua winteriana) 0.066 ppm. The content of lead metal (Pb) in the tissue of small mangrove leaves (Ryzophora apiculata) is 3.21 ppm and the mangrove leaves (Sonnerati aalba) is 3.74 ppm. For Cd levels in small mangrove leaves (Ryzophora apiculata) is 0.41 ppm while in mangrove leaves (Sonneratia alba) is 0.24 ppm

A comparison of the concentrations of heavy metals in modern and medieval shells of swollen river mussels (Unio tumidus) from the Szczecin Lagoon, SW Baltic basin

The shells of mussels, live-collected bivalves or during archaeological excavations, can be used as bioindicators of current and historical levels of heavy metal contamination. In this study, we examined the shells of Unio tumidus, commonly found in the Baltic Sea region, and determined the concentrations of Zn, Cu, Fe, Pb, Ni, and Cd in samples from the 10th, 11th, and 21st century from the area of the Szczecin Lagoon. The average levels of heavy metals (in μg g−1 dry weight) in the shells from the Middle Ages were: 137.5 (Fe), 3.87 (Zn), 0.789 (Cu), 0.012 (Pb), 0.047 (Ni), and 0.0009 (Cd). Shells from the 21st century were significantly (P<0.05) more abundant in Fe, Cu, Ni, Pb, and Cd (rates of increase: 1.96×, 3.54×, 2.71×, 2.08×, and 3.55×, respectively) than shells from the Middle Ages. These results reflect contemporary anthropogenic pollution of the environment with heavy metals and confirm the possibility of using U. tumidus shells in the assessment of heavy metal pollution levels.

Analisis Logam Timbal (Pb) sebagai Pembelajaran Menggunakan Model Problem Based Learning Kabupaten Kepulauan Sangihe

The impact of the use of refined petroleum on potential pollution in mangrove allows the presence of lead metal (Pb) in the Sangihe Islands Restoration and Learning Center and the use of mangroves in the Sangihe Islands Restoration and Mangrove Learning Center as a place of learning has not been carried out to the full. Therefore, in this regard, a study was carried out by analyzing Pb metals in sediments, Gastropod shells and Bivalvia shells in the research subsystem zone of the Sangihe Islands Restoration and Mangrove Learning Center which were then designed into learning designs using a model of problem based learning. The research method used is an exploratory method. Pb metal analysis was performed using an Atomic Absorption Spectrophotometer instrument resulting in an average Pb metal in sediments was 0.402 ppm, in Bivalvia shells was 0.04283 ppm and Gastropods shells was 0.0654 ppm. Based on the results of the analysis, it can be concluded that the presence of Pb metal in sediments, Bivalvia shells and Gastropod shells then yields four main questions in the learning design with Sub-Impacts of the Use of Petroleum using the problem based learning model.

Survey of aflatoxin B1 and heavy metal contamination in peanut and peanut soil in China during 2017–2018

Peanut, as a nutritious, healthy and delicious food, is susceptible to contamination by aflatoxin B1 (AFB1) and heavy metals, which has an adverse impact on the healthy development of peanut industry in China. This research was to evaluate the contamination of AFB1 and heavy metals (cadmium, chromium, lead, tin, copper and zinc) in peanut, to analyze the difference of AFB1 and heavy metal contamination in peanut in the four main peanut producing regions (Northeast area, Yellow River basin, Yangtze River basin and Southeast coast), and to analyze and discuss the difference of heavy metal content in peanut kernel, peanut shell and peanut soil. The results showed that the mean concentration of AFB1 in peanut was 1.08 μg/kg, and the detection rate of AFB1 was 33.80%. There was no significant difference in AFB1 contamination of peanut between 2017 and 2018. The most serious AFB1 contamination region was the Yangtze River basin, followed by the Southeast coast, the Yellow River basin and the Northeast area. The average levels of cadmium (Cd), chromium (Cr), lead (Pb), tin (Sn), copper (Cu) and zinc (Zn) in peanut kernel were 0.18, 0.44, 0.03, 0.01, 9.24 and 31.42 mg/kg, respectively. There was a significant difference in the mean content of heavy metals (Cr, Sn, Cu and Zn) in peanut kernels between 2017 and 2018. The mean content of Cd in peanut kernel was the highest in Northeast area, and there was no significant difference in the mean content of Pb in the four main peanut producing regions. The average concentration of other heavy metals (Cr, Sn, Cu and Zn) in peanut kernel in south of China (Yangtze River basin and Southeast coast) was higher than that in north of China (Northeast area and Yellow River basin). Due to the different bio-accumulation ability of peanut kernel and peanut shell to different heavy metal, the average levels of heavy metals in peanut kernel and peanut shell were different. The ability of peanut kernel to bio-accumulate Cd, Cu and Zn was stronger than that of peanut shell, and the ability of bio-accumulate of Cr, Pb and Sn was weaker than peanut shell. There was a significant positive correlation between heavy metal pollution of peanut and heavy metal content in soil. In conclusion, the situation of AFB1 and heavy metal contamination in peanut in China was not optimistic, and the pollution of peanut in south of China was more serious than that in north of China. Therefore, the control and prevention of AFB1 and heavy metal in peanut should be strengthened.

Distribution and accumulation ability of heavy metals in bivalve shells and associated sediment from Red Sea coast, Egypt.

Concentrations of Fe, Mn, Cu, Zn, Pb, Ni, Cd, and Co in molluscan shells and associated surface sediments from four sites on the Gulf of Aqaba and Red Sea coasts, Egypt, were measured by using atomic absorption spectrophotometer. The results revealed an apparent difference in the ability of each species regarding accumulating heavy metals in its shell. These results showed that Tridacna squamosa has the highest accumulation ability for Pb, Ni, and Zn, and Chama pacifica has the highest accumulation capability for Co and Cd, whereas Periglypta reticulata has the highest accumulation ability for Cu. The results also showed that there is a positive correlation between the concentration of Cu, Zn, Pb, and Ni and the size of shell. Simultaneously, there is a negative correlation with Fe, Mn, Co, and Cd. The results of bio-accumulation of molluscan species were consistent with the enrichment factors for sediments, where the Hurghada site was extremely enriched with Pb and very enriched with Cu, Zn, and Ni. Moreover, the Quseir site was extremely enriched with Cd and very enriched with Pb. The Um al-Sid site was severe enriched with Cd and Pb. Meanwhile, the Ras Mohamed site was severe enriched with Pb and nearly unpolluted with other metals. Heavy metals can enter the studied ecosystem by terrigenous and anthropogenic sources as a weathering process of the nearby beaches and mountains, ship maintenance, industrial activities, wastewater, and traffic exhaust.

Evaluating a 5-year metal contamination remediation and the biomonitoring potential of a freshwater gastropod along the Xiangjiang River, China.

Effective remediation of heavy metal pollution in aquatic systems is desired in many regions, but it requires integrative assessments of sediments, water, and biota that can serve as robust biomonitors. We assessed the effects of a 5-year metal contamination remediation along the Xiangjiang River, China, by comparing concentrations of trace metals in water and surface sediments between 2010-2011 and 2016. We also explored the trace metal biomonitoring potential of a freshwater gastropod (Bellamya aeruginosa). Metal concentrations in water (means and ranges) dropped over time to within permissible limits of drinking water guidelines set by China, USEPA, and WHO in 2016. Although sediment means and ranges of Cd, Pb, Zn, and Mn also diminished with remediation, those for Cr and Cu slightly increased, and all six metals retained concentrations higher than standards set by China. All metals in sediments could also be associated with anthropogenic inputs using a hierarchical clustering analysis, and they generate high potential ecological risks based on several indices, especially for Cd and As. The bio-sediment accumulation factors of all measured trace metals in gastropod soft tissues and shells were lower than 1.0, except for Ca. Trace metal contents in gastropods were positively correlated with those in water and surface sediments for As (soft tissues) and Cr (shells). Collectively, our results do not yet highlight strong beneficial effects of 5-year remediation and clearly illustrate the heavy metal pollution remaining in Xiangjiang River sediment. Additional physical, chemical, and biological measurements should be implemented to improve sediment quality. We further conclude that gastropod soft tissues and shells can be suitable biomonitors of spatial differences in some heavy metals found within river sediments (e.g., As, Cr).

Heavy metal concentrations in cocoa beans (Theobroma cacao L.) originating from East Luwu, South Sulawesi, Indonesia

Concentrations of some heavy metals (Pb, Cu, Cd, As and Hg) were assessed for cocoa beans (Theobroma cacao L) originating from East Luwu, South Sulawesi, Indonesia after five-day fermentation. Consisting of PB 123, BR 25, and MCC 02 cocoa clones, the spectrophotometric analysis showed that concentrations of Pb, Cd, As and Hg in the cocoa beans over the three clones was below the detection limits of 0.100; 0.050, 0.010 and 0.005 mg/kg. For Cu, they were 19.343; 10.391, and 18.594 mg/kg respectively, but still below the maximum critical levels, established by the European Food Safety Authority (EFSA). Concentrations of those five heavy metals in the bean shells were found to be parallel to those in the cocoa beans, except for Pb.

Analisis Cemaran Logam Berat Timbal (Pb) Dalam Kerang Darah (Anadara granosa) dan Kerang Patah (Meretrix lyrata) di Muara Angke Menggunakan Spektrofotometer Serapan Atom

ABSTRAK : Heavy metal pollution of waters by oceans where place biota live is very dangerous because that consumed by many people. One of types biota that utilized because a large population as a food ingredients that is favored by the public is the blood shell (Anadara granosa) and white clam (Meretrix lyrata). Contamination of heavy metals in shell that commonly consumed by Indonesian people may cause various health problems. The study aimed to determine levels of lead (Pb) in blood shell (Anadara granosa) and white clam (Meretrix lyrata) from Muara Angke were analyzed by Atomic Absorption Spectrophometry (AAS) at specific wavelength, which 283,3 nm. Results this search showed that blood shell contained lead 1,1267; 0,0939; 0,4692 µg/g wet weight, and white clam 0,8450; 0,4883; 0,7323 µg/g wet weight. Under the regulation set by Badan Standarisasi Nasional 2009, lead levels in blood shell (Anadara granosa) and white clam (Meretrix lyrata) is still viable to consumed and have not crossed the line safely determined by BSN 2009 for this type of kekerangan i.e. 1.5 µg/g. Keywords : Lead, blood shell, white clam, Muara Angke, Atomic Absorption Spectrophotometer.

Bioaccumulation of Cadmium and Lead in Prickly Pen Shell in Seribu Archipelago

Jakarta Bay waters contaminated with heavy metals, so that the waters of the Thousand Islands are also potentially contaminated with heavy metals. The purpose of this study were to determine the condition of the water quality on the Panggang Island and Karya Island, analyze contamination of heavy metals (Cadmium and Lead) in water, sediments and Prickly Pen Shell and then the correlation. Based on Ministry of Environment decree No. 51/2004, water quality in the Panggang Island and Karya Island tend toward to low category. Cadmium and lead concentration in the water on October exceed the quality standards. In the sediment on July and October at Karya Island, concentration of cadmium were exceed the quality standar by RNO. On the other hand, cadmium and lead concentration on Prickly Pen Shell still below standard quality from decree of Director General of POM RI No. 03725. We found highest positive correlation were found between cadmium and lead accumulation in the water and on the Prickly Pen Shell, then positive correlation between cadmium and lead in the water and in the sediment. For the heavy metal contamination, we found contamination of cadmium correlation were higher than lead contamination.

EVALUATION OF IRAQI COASTS USING LITTORAL AND MARINE BIVALVE SHELLS

The geochemical analysis of both of Crassostrea cucullata and Chione californensis shells and hydrochemical analyses of water are carried out to study the environmental evaluation in the Iraqi coasts. Shells and water are collected during low tide period (March to August 2011), from seven different stations (Fadakia, Rass AlBishah, Khor Abdullah, Khor Shytianah, Hacham Island, Khor AlZubair and Shatt AlBasrah). The hydrochemical analyses reflect two zones of water salinity, Fadakia and Shatt AlBasrah of brackish water with TDS range (15148 – 18130 ppm), and the other marine coastal sites of saline water with TDS range (34123 – 45220 ppm). XRD of shells of Chione californensis reveals that they have two layers, an inner layer constitutes of aragonite and outer layer constitutes of calcite, while the shells of Crassostrea cucullata have only calcite layer. Water salinity increasing associate with increase of major chemical constituents of oyster shells. Mg/Ca and Sr/Ca values in the coastal line Crassostrea cucullata shells are higher than Fadakia and Shatt AlBasrah shells that may be due to increment of salinity in the coastal line compared with Fadakia and Shatt AlBasrah areas. Zn, Cu, Pb, Sr, and Cr metals in Khor Shytianah Crassostrea cucullata are higher than the other areas may attribute to higher contamination in this area. The chemical constituents of CaO%, MgO, Sr/Ca and Mg/Ca in Khor Shytianah and Hacham Island Chione californensis shells are higher than Khor Abdullan shells, this result may be indicator to higher salinity of sea water in Khor Shytianah and Hacham Island compare with the sea water of Khor Abdullah. Heavy metals (Co, Ni, Rb, Sr, Zn, Ba, Cr, Th, Mo, and Pb) in Khor Shytianah Chione californensis shells were more than the other shells may be due to high range of contamination of sea water by this metal.

Effects of anthropogenic activities on the heavy metal levels in the clams and sediments in a tropical river.

The present study aimed to assess the effects of anthropogenic activities on the heavy metal levels in the Langat River by transplantation of Corbicula javanica. In addition, potential ecological risk indexes (PERI) of heavy metals in the surface sediments of the river were also investigated. The correlation analysis revealed that eight metals (As, Co, Cr, Fe, Mn, Ni, Pb and Zn) in total soft tissue (TST) while five metals (As, Cd, Cr, Fe and Mn) in shell have positively and significantly correlation with respective metal concentration in sediment, indicating the clams is a good biomonitor of the metal levels. Based on clustering patterns, the discharge of dam impoundment, agricultural activities and urban domestic waste were identified as three major contributors of the metals in Pangsun, Semenyih and Dusun Tua, and Kajang, respectively. Various geochemical indexes for a single metal pollutant (geoaccumulation index (I geo), enrichment factors (EF), contamination factor (C f) and ecological risk (Er)) all agreed that Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn are not likely to cause adverse effect to the river ecosystem, but As and Pb could pose a potential ecological risk to the river ecosystem. All indexes (degree of contamination (C d), combined pollution index (CPI) and PERI) showed that overall metal concentrations in the tropical river are still within safe limit. River metal pollution was investigated. Anthropogenic activities were contributors of the metal pollution. Geochemical indexes showed that metals are within the safe limit.

Impact of environmental quality on the mobility of heavy metals in plants under the conditions of agroforestry systems

The cultivation of tomatoes in two experimental sites under the conditions of unprotected and protected by a forest belt and in two control sites outside the influence of highways has been studied following irrigation with water of different composition. It has been found that the pollution from highways causes not only an increase in the concentrations of heavy metals in leaves, stems, fruits, and seeds of tomatoes, which is well-known, but also induces changes in their structure within the mobility series of elements. This influence has an adverse result during irrigation with the water of different composition. The effect of self-organization of plants by the example of tomatoes in agroforestry systems leads to a significant transfer of heavy metals in the shell of seeds, thereby protecting the seed kernels from excessive pollution with heavy metals.