Heavy Metal Concentrations Of Cd Research Articles

Heavy Metals Concentration in Sardina pilchardus (Walbaum, 1792) from the Moroccan Mediterranean Coast and Potential Human Health Risk Assessment

Due to their toxicity, long persistence, bioaccumulative nature, and biomagnification in the food chain, heavy metals pose a serious hazard. The aim of this study was to evaluate the health risks associated with the consumption of Sardina pilchardus (Walbaum, 1792) and to study the spatiotemporal dynamics of four potentially toxic metallic elements. Three hundred and sixty specimens of sardine were collected between December 2020 and October 2021 at three Mediterranean coast sites, Beni-Ensar, Ras el Ma, and El-Houceima, in the northeast region of Morocco. The toxic metallic elements were evaluated by assessing the contamination level of cadmium (Cd), mercury (Hg), lead (Pb), and arsenic (As) in the muscle, liver, and gills of sardine from the Mediterranean Moroccan coast. The results showed a significant effect of the study area, organ, and season ( p > 0.05 ) on Moroccan Mediterranean sardine heavy metal contamination levels. Regardless the location and season, the liver presents the higher concentration of the studied metals ( p < 0.05 ). The highest heavy metal concentrations of Cd (0.408 μg·g−1 wet weight (ww)), Hg (0.044 μg·g−1 ww), and As (6.74 μg·g−1 ww) were found in winter while the concentration of Pb was the highest in autumn (0.056 μg·g−1 ww). Furthermore, the lowest contamination of metal levels was found in the spring. El-Houceima region contains the highest values for Hg (0.093 μg·g−1 ww), Pb (0.018 μg·g−1 ww), and As (7.73 μg·g−1 ww). However, the highest values for Cd (0.172 μg·g−1 ww) were recorded in Beni-Ensar. Regarding the assessment of possible risks to human health, the results showed that the indices are below the established safety values in the case of estimated weekly intake, and target hazard quotient (THQ). In contrast, the carcinogenic risk index and total THQ were above the threshold limits and thus represented a potential carcinogenic risk to human health.

Source Apportionment of Heavy Metal Contamination in Urban-Agricultural-Aquacultural Soils near the Bohai Bay Coast, Using Land-Use Classification and Google Satellite Tracing

Heavy metal concentrations of Cd, As, Pb, Cu, Cr, and Hg were investigated for 86 soil samples in Jinzhou near the Bohai Sea in China, in order to identify what anthropological activities influenced their distribution levels. Ordinary cokriging (OCK) was utilized to map six heavy-metal distributions by incorporating their main environmental influencers. The resultant p values for the six OCK mapping models of 0–2.78% indicated good statistical significance of the models, and the relative mean absolute errors of 4.82–12.53% and relative root mean square errors of 6.23–18.21% indicated allowable predication precision for their concentrations. The contamination distributions by OCK mapping were then graded based on the standards of the China National Environmental Monitoring Center and the Chinese Environmental Protection Administration, which showed that Cu and As contaminations in parts of this area were over the natural level but not polluted, Cr contamination was omnipresent over the natural level in this area and even reached the polluted level in parts of this area. The graded contamination maps that were overlapped with land-use maps and Google satellite maps, as well as the verifications reported in literatures, enabled correlations of the different contamination levels of As, Cu, and Cr with human activities. Resultantly, it indicated that As and Cu contamination over the natural level may be related to agricultural planting and aquacultural activities along the coast of Bohai Bay, with the contaminants transported via watercourses; Cr contamination over the natural level may have been due to vehicle emissions; and, Cr pollution may have been from steel manufacturing and geochemical factories

Heavy Metal Concentrations of Soil, Rock, and Coal Gangue in the Geological Profile of a Large Open-Pit Coal Mine in China

Risk assessment related to heavy metals in mining areas is crucial to ensuring the sustainable development of regional ecosystems and protecting human health. However, almost all research on the impact of mining activities on environmental quality entails field monitoring of surface soils or soil profiles. Here, to compare the variety of heavy metal concentrations in the geological profile, 39 samples (including soil, rock, and coal gangue) were collected and analyzed from hundreds of meters underground in the Pingshuo coal mine (Anjialing coal mine, Antaibao coal mine, and Donglutian coal mine), which is the largest open-pit coal mine in China. The mean heavy metal concentrations of Cd, Hg, As, Pb, Cr, Cu, Zn, and Ni in soils were 0.15 mg/kg, 0.02 mg/kg, 13.70 mg/kg, 27.12 mg/kg, 70.89 mg/kg, 26.10 mg/kg, 79.88 mg/kg, and 37.68 mg/kg, respectively; most of these metals were more concentrated in the soil samples than in the rock and coal gangue samples. A potential ecological risk assessment indicated that As, Pb, Cr, Cu, Zn, and Ni in all samples showed low risk, while the ecological risk degrees of Cd and Hg were higher and contributed most to the total risk index (RI). The highest E_r^i value (92.94) for Cd was found in rock samples, contributing to approximately 55.18% of the to tal RI. For Hg, four rock sampling sites had the highest E_r^i values (427.70, 270.78, 198.96, and 188.70), contributing approximately 68.36–88.07% of the total RI. Ranked after soil (0.15 mg/kg), limestone and shale showed high mean Cd concentrations (both 0.13 mg/kg). The highest mean concentration was found in coal gangue samples (0.1 mg/kg). Compared with the other types of samples, the mean concentrations of Cr, Cu, and Ni in soils, limestone, and mudstone were relatively higher. At different sites, heavy metal concentrations varied greatly at different depths, owing to diverse sample types and rock types. Correlations between heavy metals and soil nutrients indicated that N and P were closely correlated with heavy metals. Comparing the proportions of different heavy metals in various types of samples showed that heavy metals in soils were extremely similar to those in limestone, mudstone, and shale, implying that soils might indirectly inherit their features from their parent material.

Underestimated heavy metal pollution of the Minjiang River, SE China: Evidence from spatial and seasonal monitoring of suspended-load sediments

Previous assessments on rivers in SE China with highly developed economy and enormous population indicate diverse and relatively low particulate heavy metal pollution levels. However, the controlling mechanisms for heavy metal enrichment and transport remain enigmatic. Here, we target a mesoscale mountainous river, the Minjiang River, and obtain grain size, mineralogical and heavy metal concentration (Pb, Cd, Cr, Mn, Mo, Zn, V, Co, Ni, Cu) data from seasonal suspended particulate matter (SPM) near the river mouth, riverbed sediments and SPM samples from mainstream and major tributaries of the river. The results indicate that SPM samples have higher particulate heavy metal concentrations than riverbed sediments collected in pairs. Heavy metal concentrations of Cd, Zn, Cr, V, Co, Ni and Cu are higher in upstream SPM samples than those in downstream regions, whereas Pb, Mn and Mo concentrations don't show this spatial variation. Most heavy metals (e.g., Pb and Zn) show high concentrations in flood seasons and relatively low concentrations in dry seasons, revealing a hydrologic control. However, Cr and Mn show high concentrations in some dry season samples, suggesting incidental anthropogenic input events. The SPM-based pollution assessments using enrichment factor, geoaccumulation index and potential ecological risk index demonstrate that the Minjiang River is moderately to strongly polluted by particulate Pb, Cd, Mo and Zn contaminations and most particulate heavy metals have moderate to considerable potential ecological risks. We contend that transport and discharge of particulate heavy metals by the Minjiang River are controlled by both natural and anthropogenic forcings and the pollution levels are worse than previously known. Our findings suggest that particulate heavy metal discharge by subtropical mountainous rivers is related to sediment types and hydrologic characteristics. Therefore, high-spatiotemporal-resolution investigations on river SPM samples are highly recommended to better evaluate particulate heavy metal pollution levels and aquatic environmental conditions.

Risk assessment of soil heavy metals associated with land use variations in the riparian zones of a typical urban river gradient

Urbanization-induced land use changes in riparian area alter soil and water regimes in complex ways, which may also affect the migration and transformation of soil heavy metals and increase the risk of release. In this study, soil samples from the riparian zone of Beiyun River, which located in the rapidly urbanized Beijing metropolis, were collected and analyzed for heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn). Then their zoning distribution pattern along river (section 1 to section 4 from upper to low reaches) and the correlation of heavy metals between riparian soils and riverine sediments were investigated. Results showed that the average soil heavy metal concentrations of Cd, Cr, Cu and Zn in riparian zone were approximately 2.2, 1.7, 1.9 and 2.0 times higher than the background values. Sectionally, the concentrations of Cd, Ni, Pb and Zn displayed a decreasing order with section 2 > section 3 > section 4 > section 1, while the highest values of Cr and Cu were found in section 3. The concentrations of all heavy metals except Cr in artificial garden land were higher than those in other land use types, and the concentrations of Cr among five land use types were in the order of grass land > farmland > artificial garden land > forest land > forest-grass land. Generally, most of the heavy metals in the riverine sediments had higher contents than those in riparian zones, especially Cu and Zn. There was a decreasing order for the average geo-accumulation index (Igeo) of measured heavy metals in the soils of riparian zone: Zn (0.15) > Cr (0.08) > Cu (0.07) > Cd (−0.08) > As (−0.57) > Pb (−0.67) > Mn (−0.75) > Ni (−0.86), whereas they had different “high-low” orders in different land use types. The Igeo index indicated most regions of riparian zone were moderately polluted with Cd, Cr, Cu and Zn, especially in grass land and forest land. Also, Cd, Cr and Zn in riparian zone have positive relationships with the concentrations in riverine sediments. Health risk assessment showed that the contribution of ingestion HQ to HI was the highest among the three exposure pathways (ingestion, inhalation and dermal contact), and children had higher non-carcinogenic risk and carcinogenic risk index than adult. Our findings suggest that land use and soil in riparian zone should be protected and managed scientifically to control the riverine pollution and ensure human health.

Heavy Metal Accumulation at the Bertam Agricultural Watershed in Cameron Highlands, Malaysia

The existence of heavy metals residues in water, soil and air poses a serious risk to all living organisms. Heavy metals, such as Cd, Pb, Cr, Ni, and Hg, are major sources of environmental pollution, especially in areas with high anthropogenic and agriculture activities. The objective of this study is to determine the status of heavy metal concentrations of Cd, Cr, Ni, Pb, Zn, Cu, and Fe in the water bodies of Bertam River, which passes through agricultural areas. The water samples were collected randomly in three replicates from 10 sampling points along the Bertam River. The heavy metals in the water were extracted by using filter paper with a pore size of 0.45 mm. The extracted water sample was preserved by adding nitric acid (pH <2). Sample concentrations were then tested for metal concentrations using inductively coupled plasma mass spectrometry. In this study, the highest mean concentration was Fe (96.04 ± 90.43 ppb), followed by Zn (5.68 ± 0.2.34 ppb), Cu (5.13 ± 2.98 ppb), Cr (1.53 ± 0.19 ppb), Ni (0.85 ± 0.22 ppb), Pb (0.85 ± 1.61 ppb), and Cd (0.027 ± 0.02 ppb), where Fe> Zn> Cu> Pb> Cr> Ni> Cd. However, the concentrations of selected heavy metals in the water samples were below the standards recommended by the World Health Organization.

Seasonal variations of heavy metals content in mussels (Mytilus galloprovincialis) from Cala Iris offshore (Northern Morocco)

Heavy metal concentrations of Cd, Cr, Cu, Fe, Ni, Zn, Co, and Pb were investigated in soft tissues of Mytilus galloprovincialis coming from an aquaculture farm in Cala Iris sea of AlHoceima. Mytilus galloprovincialis were collected monthly during the period January to December 2016. The seasonal variations were affected significantly the concentrations of metals (Cd, Fe and Cr) in M. galloprovincialis. The highest heavy metal concentrations were recorded in winter (0.89 mg/kg, 673.2 and 3.330 mg/kg; for Cd, Fe and Cr, respectively) and the lowest values were founded in summer for Cd (0.646 mg/kg), and in autumn for Fe (340.1 mg/kg) and Cr (1.959 mg/kg). A significant effect of seasons on metal concentrations can be attributed to a number of biological and environmental inter-related factors. Data from this study may provide information on the use of M. galloprovincialis as a bioindicator for heavy metals pollution in the Cala Iris Sea.

Physicochemical characterization of sediments from Tajan river basin in the northern Iran

Continuous monitoring of water quality of freshwater bodies may prevent outbreak of diseases and occurrence of hazards through employment of effective protection measures. The aim of the current investigation was to determine occurrence of water and sediment pollution in Tajan River North Iran which ultimately may be a threat to recreational beaches of Caspian Sea. Water samples were analyzed for various physicochemical parameters including pH, electrical conductivity (EC), total dissolved solids (TDS), bicarbonates, sulfates, cations, chlorides and heavy metals. The concentrations of zinc (Zn), cadmium (Cd), chromium (Cr) and lead (Pb) were determined using atomic absorption spectroscopy. Similarly, sediment samples were assessed for physicochemical characteristics including pH, EC, saturation percentage, organic matter, organic carbon, texture and cations. Overall, pH, EC, organic matter, and cation values were within acceptable limits according to USEPA water quality guidelines. However, phosphorus (P) concentration up to 5.6 mg/L was considered as “unsafe” which might result in undesirable eutrophication and increased accumulation of sediment organic content leading to excessive growth of algal species in riverine ecosystem. Heavy metal concentrations of Cd (0.08 ppm) and Pb (3 ppm) were above USEPA threshold limits which may consequently affect sustainability of Tajan River. The unacceptable levels of Cd, Pb and P may produce eutrophication of Caspian Sea coasts and damage the ecosystem.

Spatial Distribution of Metals and Associated Risks in Surface Sediments Along a Typical Urban River Gradient in the Beijing Region.

Surface sediments from Beiyun River located in the rapidly urbanized Beijing metropolis were collected and analyzed for heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) to investigate their spatial distribution pattern, ecotoxicology and source identification. Results indicated the average heavy metal concentrations of Cd, Cr, Cu, Pb, and Zn were approximately 4, 2, 3, 2, and 4 times higher than their background values. Spatially, we found the concentrations of heavy metals made significant change in four sections along urbanized river gradients. The contents in midstream of urban region and farmland region (section2 and section3) were greater than those in upstream (section1) and downstream (section4). However, one-way analysis of variance for spatial analysis suggested there were no significant differences between mainstream and tributaries. The geo-accumulation index (I geo) used to assess the sediment quality exhibited there was a decreasing order for the average I geo of measured heavy metals: Zn (0.82)>Cd (0.53)>Cu (0.50)>Cr (-0.08)>Pb (-0.45)>Ni (-0.96)>Mn (-0.97)>As (-1.01), whereas they had different "high-low" orders at different sampling transects. Ecological risk index values showed that section2 and section3 revealed a high and moderate ecological risk, respectively. Furthermore, principal component analysis indicated the first principle component explained 64.73% of total variance with the main pollutants of As, Cr, Ni, Zn, and Cu which were probably controlled by the mixed sources covering natural factors and anthropogenic input.

The Comparison of Growth, Bioaccumulation of Heavy Metals, and Cia7 Gene Expression Levels between Two Strains of Chlamydomonas reinhardtii

Chlamydomonas reinhardtii has been a valuable model organism in the study of heavy metal homeostasis and tolerance in photosynthetic organisms. This alga has a novel gene Cia7 isolated from one of the high CO2 requiring mutants designated as cia7. CIA7 has the presence of four conserved cysteines and thus is a putative metal-binding protein. The purpose of this study was to compare the growth and the bioaccumulation of metals of the wild type, D66 and the mutant, cia7 in the absence and presence of heavy metals. It also aimed to compare Cia7's expression levels in both strains in the absence and presence of heavy metals. The heavy metals used were Cd and Pb. Algal cultures were grown on different heavy metal concentrations of Cd or Pb for sixteen days. Chlorophyll absorbance and cell count were monitored every four day to assess algae growth. To test bioaccumulation, cells were exposed to 50 µM Cd or Pb and grown for one week prior to analysis using ICP-OES. Gene expression of Cia7 under heavy metal stress was determined by RT-PCR after exposing algal cell to Cd or Pb treatments. Results showed that heavy metal concentrations do not influence wild type growth as much as in the mutant. Exposure to Cd and Pb significantly affects (p<0.05) chlorophyll content and cell count in the mutant strain. Results showed a significant difference (p<0.05) in the bioaccumulation for D66 exposed to 50 µM Cd. Results also showed a significant difference (p<0.05) in the bioaccumulation for D66 exposed to 50 µM Pb. On the other hand, cia7 only showed bioaccumulation of Pb, not Cd. Gene expression results showed that is possible for Cia7 to be involved in specific heavy metal resistance to Cd.

Influence of Landfill Operation and Tropical Seasonal Variation on Leachate Characteristics: Results from Lysimeter Experiment

This study demonstrates the influence of lysimeter operational condition and tropical seasonal variation of leachate characteristics generated from municipal solid waste (MSW) deposited in landfill lysimeter at KUET campus, Bangladesh. Three different situations of landfill were considered here as well as both the open dump lysimeter-A having a base liner and sanitary landfill lysimeter-B and C at two different types of cap liner were simulated. The leachate characteristics, leachate generation and climatic influence parameter had been continually monitored, from June 2008 to May 2010. This period covers both dry and rainy season. The leachate generation followed the rainfall pattern and the open dump lysimeter-A without top cover was recorded to have the highest leachate generation. Moreover, the open dump lysimeter-A had lower concentration and load of total kjeldahl nitrogen (TKN), ammonia nitrogen (NH4-N) and dissolved organic carbon (DOC), while chemical oxygen demand (COD) and biological oxygen demand (BOD5) concentration were higher compared with sanitary lysimeter-B and C. On the other hand, sanitary lysimeter-B, not only had lowest leachate generation, but also produced reasonably low COD and BOD5 concentration compared with open dump lysimeter-A. Based on evaluated results, it was also concluded that metal concentrations which were comparatively higher in leachate of open dump lysimeter were Ca and K, however, the heavy metal concentrations of Cd, Cu, Zn and Mn, and those apparently lower were metals of Na, Mg and Fe as well as heavy metals of Cr, Pb and Ni. However, significant release of heavy metals under open dump lysimeter was observed compared to sanitary lysimeter. Moreover, meaningful correlation between DOC and leaching of Cu and Pb was observed. Result reveals that lysimeter operational mode had direct effect on leachate quality. Finally, it can be concluded that the knowledge of leachate quality will be useful in planning and providing remedial measures of proper liner system in landfill design and leachate treatment.

Heavy metals in urban soils with various types of land use in Beijing, China

Heavy metal concentrations of Cd, Cr, Cu, Ni, Pb and Zn were investigated for 127 urban soil samples collected from business area (BA), classical garden (CG), culture and education area (CEA), public green space (PGS), residential area (RA) and roadside area (RSA) in Beijing. The distribution of Cd, Cu, Pb and Zn was mainly affected by anthropogenic sources, with their mean concentrations much higher than the background values of Beijing, while Cr and Ni were from natural sources. Among the 6 types of land use, the concentrations of Cd, Cu, Pb and Zn in CG were significantly higher than those in the other 5 types of land use (p<0.05), which were due to their historical use such as pigments, wood preservation and brassware. For the other 5 types of land use except CG, the mean concentration of Cd in RSA was significantly higher than those in BA, CEA, PGS and RA (p<0.05), suggesting Cd was mainly from traffic sources. The distribution maps revealed that the concentrations of Cu, Pb and Zn showed decreasing trends from the center to the suburb of Beijing, they increased with the age of the urban area.

Evaluation of Heavy Metals in Fish of the Sepetiba and Ilha Grande Bays, Rio de Janeiro, Brazil

Muscles, gonads, and liver tissues of fish caught in Sepetiba and Ilha Grande Bay were analyzed to assess levels of heavy metal concentrations of Cd, Fe, Zn, Pb, Ni, Cu, and Cr. Levels of Cr surpassed the maximum permissible concentration in muscle, followed by Zn in some species. Pb, Cu, and Cd presented concentrations above maximum permissible levels in gonads and liver only. Fe presented concentrations in viscera comparable to those of highly polluted areas, although there are no standards available for this metal. Ni was the only metal that did not present contamination in the fish tissues examined. Overall, fish caught in Sepetiba Bay showed higher metal concentrations than those from Ilha Grande Bay, but the latter also presented high metal concentrations in several samples.

Evaluation of two selected industrial wastes for disposal on cropland

The effect of a bioorganic, sugar lime (SL) and an organic, latex (LX), industrial waste product on runoff, soil erosion, soil aggregation, corn grain yield, and contamination of soil by heavy metals were investigated in a field experiment for two years. Soil aggregation, measured as wet aggregate stability, runoff and soil erosion were not changed by the application of the waste products. Corn grain yield from treated plots were similar to the control. None of the heavy metal concentrations of Cd, Cr, Cu, Ni and Pb were of environmental concern. Although the Na content in sugar lime was high, the relative amount of it with respect to the Ca and Mg content will not cause a problem with regard to changes in the sodium adsoprtion ratio. The composition of the latex cannot be guaranteed by the industry, but that of sugar lime was relatively constant. Thus, sugar lime may be permitted for application on general agricultural soil with intermittent monitoring of Na and Ba content in soil.