Average Concentrations Of Heavy Metals Research Articles

Impact of tourism activities on the distribution and pollution of soil heavy metals in natural scenic spots on the northern slope of Tianshan Mountain

Human activities can significantly impact the natural ecosystem. As an important part of terrestrial ecosystems, soil participates in energy and material cycle. With the continuous intensification of human activities, soil undergoes increasingly serious disturbance. Under the influence of global change and human activities, the variability of heavy metals in soil is worthy of further discussion. Taking Lujiaowan and Juhuatai Scenic Spot on the northern slope of Tianshan Mountain as the research area, this study investigated the concentrations of Pb, As, Zn, Cu and Mn in the soil and analyzed their distribution and pollution levels. Meanwhile, the main sources of soil heavy metals were explored using autocorrelation analysis and principal component analysis. Results showed that the order of the average concentration of heavy metals in the study area was as follows: Mn> Zn> Cu> Pb> As. None of them exceeded the national soil environmental quality level II standard, and the average concentrations of Zn, Cu, and As exceeded the background value of Xinjiang soil, reaching a light pollution level. In addition, the distribution of heavy metals in soil displayed a regular trend, and a positive correlation was found between disturbance intensity and heavy metal concentration. The geoaccumulation index also showed that the five heavy metals in the study area had lower pollution degree compared with the background value in Xinjiang. The order of potential ecological risk was As > Cu > Pb > Zn > Mn.

Spatial variation of heavy metals and their ecological risk and health risks to local residents in a typical e-waste dismantling area of southeastern China.

There is an increasing concern that soils in e-waste recycling regions are severely contaminated by unregulated e-waste dismantling activities. Hence, it is urgent to reveal the spatial variation of hazardous elements in arable lands close to e-waste stacking and dismantling areas and their potential risks to human beings. We collected 349 topsoil samples based on an intensive grid of 100m × 100m in southeastern China. The average concentrations of heavy metals were 1.25 (Cd), 35.44 (Ni), 77.68 (Cr), 77.38 (Pb), 122.14 (Cu), 203.39 (Zn), 0.21 (Hg), and 4.74 (As) mg kg-1, respectively. Compared to the risk screening values of hazardous elements in Chinese agricultural land, Cd and Cu were severely accumulated in the soils. The results of ecological risk analysis revealed that Cd posed the crucial risk among the studied elements. However, the levels of non-carcinogenic and carcinogenic risk were still within the acceptable quantity for adults. Spatial distribution by kriging interpolation displayed that the heavy metals were mainly distributed close to e-waste dismantling sites.

Heavy Metal Contamination and Ecological Risk Assessments in Urban Mangrove Sediments in Zhanjiang Bay, South China.

With the acceleration of industrialization and urbanization, increasing attention has been paid to the problem of heavy metal pollution in mangroves and its ecological restoration. Urban mangroves can be used to measure the impact of human activities on the urban ecological environment because mangroves are sensitive to human activities. However, studies on the evaluation of heavy metal elements in urban mangroves are still limited. Consequently, this study selected the urban mangroves in a central commercial area of Zhanjiang Bay as a case study to investigate the content and distribution of the heavy metals (Co, V, Cu, Pb, Ni, As, Cd, and Hg) in mangrove surface sediments. Risk levels and possible sources of heavy metals were evaluated based on multivariate statistical analysis methods and pollution indices. The results showed that the average concentrations of heavy metals for Co, V, Cu, Pb, Ni, As, Cd, and Hg were 2.91, 29.96, 18.24, 20.07, 7.86, 5.0, 0.20, and 0.09 mg/kg, respectively. Cd, Cu, and Hg were most prominent within the Zhanjiang Bay mangrove sediments, whereas other metals showed a low contamination factor of therm. Cd displayed a high potential ecological risk followed by Hg and Cu. The sampling site, the sewage outlet sampling site, exhibited the highest pollution degree followed by the surrounding area of the sewage outlet sampling site. Those polluted heavy metals could arise from anthropogenic sources, including domestic sewage and automobile exhaust emission. Correlation analysis between the heavy metals and physicochemical properties indicated that fine particles and organic matter play a key role in controlling heavy metal enrichment.

A comparison of two digestion methods and heavy metals determination in sediments

Abstract This study was conducted to evaluate the levels of heavy metal concentrations in sediments and also involves a comparison of two different digestion protocols. The first digestion procedure was done with a mixture of hydrochloric acid and nitric acid while the second digestion method was done using the United States Environmental Protection Agency method 3052 which comprises nitric acid, hydrofluoric acid, hydrochloric acid, and hydrogen peroxide. The sediment samples were analyzed for cadmium, copper, iron, lead, zinc, chromium, manganese, nickel (Cd, Cu, Fe, Pb, Zn Cr, Mn, and Ni) with the aid of atomic absorption spectrophotometer. Concentrations of metals ranged 0–7.0 mg/kg for Cr, 0.5–20.0 mg/kg for Cd, 10.8–112.0 mg/kg for Fe, 0.10–7.20 mg/kg for Pb, 45.69–184.96 mg/kg for Cu, 1.0–73.75 mg/kg for Zn, 1.5–19.7 mg/kg for Mn and nd −3.0 mg/kg for Ni. The order of concentrations of the metals in the samples are Cu > Fe > Zn > Cd > Mn > Pb > Cr > Ni. The second digestion method yielded higher levels of metal concentration. Comparison with theWorld Health Organization (W.H.O) standards for marine sediments showed that the average concentrations of heavy metals were within the permissible limits. Close monitoring and more publicity are further needed to discourage further pollution of the area.

Biomonitoring and phytoremediation potential of the leaves, bark, and branch bark of street trees for heavy metal pollution in urban areas.

Tree tissues can accumulate heavy metals from the environment. We therefore aimed to evaluate the presence of the metals Pb, Cr, Mn, Cu, and Zn in four street tree species, namely Ailanthus altissima, Broussonetia papyrifera, Pinus tabuliformis, and Rhus typhina, along the highway side of Beijing, China. Sampling from the leaves, trunk bark, and branch annual segment bark of trees was conducted in the summer of 2021, and the concentration of heavy metals was determined. The results revealed the highest average concentration of total heavy metals in the R. typhina leaves (23.724 mg/kg) and barks (14.454 mg/kg). The maximum bio-concentration factor was noted for Zn in the B. papyrifera leaves (0.36) and P. tabuliformis barks (0.21). The maximum comprehensive bio-concentration index was observed for the B. papyrifera leaves (0.225) and P. tabuliformis bark (0.108). The maximum metal accumulation index was measured in the R. typhina leaves (29.682) and bark (12.407). Based on the air-originated metals, P. tabuliformis showed the highest dust collection capacity. In general, B. papyrifera and P. tabuliformis exhibited the highest absorption rate from the soil relative to the other studied species. R. typhina demonstrated the strongest phytoremediation ability for heavy metal pollution in air. In addition, our results proved that the branch annual segment bark of P. tabuliformis is an excellent record carrier that can be used to monitor heavy metal pollution in a specific time duration in an urban area.

Heavy Metal Accumulation among Different Organs of Cultured Rohu and Catla along with Evaluation of Enzymatic Activities in Examined Organs

Aims: The present study was carried out to determine the concentration of heavy metals and to evaluate whether there are any serious toxic effects of the widely exposed heavy metals namely arsenic (As), lead (Pb) and chromium (Cr) in different tissues of two commercially important cultured fish Rohu (Labeo rohita) and Catla (Gibelion catla)
 Study Design: The study was designed based on Randomized Block Design (RBD) to avoid all kinds of possible biases as well as for ensuring the representation of different fish farms. Three replications were maintained to deal with the possible errors caused by sampling.
 Methodology: Lead (Pb), Arsenic (As) and Chromium (Cr) were analyzed in a graphite furnace (GBCGF 3000 with Zeeman background corrector) with an auto sampler using Atomic Absorption Spectrophotometer (AAS). ALP (alkaline phosphates) activity of liver, Kidney and muscle was assayed using the standard method stated by Garen and Levinthal (1960) [1]. ATPase enzyme activity was determined to follow the standard method stated by Post and Sen (1967) [2]. During each month, ten individuals of the targeted two species each incorporating with three replications were collected from four intended fish farms, with a total of 240 fishes in the study period.
 Results: The obtained results stated the highest concentrations of all heavy metals (except arsenic) were recorded in Rohu fish with no significant difference with the other investigated fish species Catla. Organ wise heavy metal concentrations in Rohu (Labeo rohita) fish showed that Lead (Pb) concentrations were higher in all organs compared to other investigated heavy metals. The recorded values of Pb in gills, livers, kidneys, and muscles were 0.021, 0.021, 0.028 and 0.008 ppm respectively. In case of Arsenic (As), the highest concentration was recorded in kidneys while the Chromium (Cr) showed higher accumulation in the muscles. While it comes to Catla (Gibelion catla) fish, similar results were demonstrated where Lead (Pb) concentration was the highest and Chromium (Cr) concentration was lowest. Among all the three heavy metals, the accumulation trend of Arsenic (As) was found highest in gills of Catla (Gibelion catla) but Lead (Pb) and Chromium (Cr) were accumulated in high concentration in kidneys of the same species. The average concentration of different heavy metals in the two investigated fishes were lower than the standard recommended value (0.01ppm) except for Arsenic (As) in Catla (Gibelion catla) which was 0.013ppm. Enzymatic activities like ATPase and ALP were recorded highest in kidney tissue and the lowest in muscle in case of both fish species.
 Conclusion: Even though the average values of Arsenic in Catla (G. catla) fish was slightly higher than the recommended value suggested by WHO [3], the concentration is lower in edible part muscle which in turn indicates that the cultured Rohu (L. rohita) and Catla fishes in the Chattogram region are safe for human consumption.

Heavy metal concentrations and health risk assessment in urban soils of Neyshabur, Iran.

This study aimed to determine and analyze heavy metal pollution in the street dust of Neyshabur city of Iran. In this regard, the concentration of ten heavy metals, including Al, Fe, Mn, Zn, Cu, Cr, Ni, Pb, Co, and Cd, was measured at 60 street dust samples. The samples from Neyshabur city in three zones were collected, including high traffic, low traffic, and rural. Twenty samples in each area, 10-sample in summer and 10-sample in winter, were studied. The average concentration of the target heavy metals (mg kg-1) in the street dust samples was as follows: 50514.09 for Al, 42473.33 for Fe, 647.4 for Mn, 230.07 for Zn, 146.44 for Cu, 96.18 for Cr, 73.25 for Ni, 40.56 for Pb, 14.86 for Co, and 1.32 for Cd. Based on the findings, it can be concluded that non-carcinogenic risk assessment for all quantified heavy metals was less than the allowed values. In addition, the carcinogenic risk assessment of these metals indicated high carcinogenic-risk indexes through exposure to Cr for adults and exposure to Cr, Co, and Ni for children. As a consequence of this investigation, efforts to avoid the transmission of heavy metals in the environmental soil of Neyshabur city should be encouraged.

Heavy Metal Distribution and Bioaccumulation Combined With Ecological and Human Health Risk Evaluation in a Typical Urban Plateau Lake, Southwest China

Heavy metal contamination in lakes caused by the rapid industrialization and urbanization is a serious problem. In this study, 12 heavy metals were systematically surveyed in aquatic environment and organisms of Dianchi Lake. Results showed that heavy metals pollutions in surface water exhibited a decreasing order of Ba > Fe > Zn > Mn > As > Ni > Cr > Cu > Pb > Cd > Co, equipped a consistency in spatial distribution, seriously contaminating the northern and southern parts. The average concentration of sedimentary heavy metals appeared in an order of Fe > Mn > Zn > Ba > Cu > Pb > Cr > As > Ni > Co > Cd > Ag. The main existing fraction (51.9–75.0%) of Cu, Pb, Cr, As, Fe, Co, Ni, Ag, and Ba in sediments was residual fraction, whereas the exchangeable fraction (40.9–62.0%) was the dominant component for Cd, Zn, and Mn. Among the selected aquatic organisms, Cu, Pb, Zn, and Ag possessed a strong bioaccumulation effect, followed by Mn, Fe, Co, and Ni. Ecological risk assessment indicated that Cu, Cr, and Zn were the dominant heavy metal contaminants in surface water; Cd presented the disastrous risk and accounted for the considerable proportion of ecological risk in sediments. Human health risk evaluation showed that the selected aquatic products of Dianchi Lake were not absolutely safe, and As was the major contributor. This study systematically revealed heavy metal distributions in aquatic environments, which was conductive to environmental safety and human health.

Creating wealth from waste: An approach for converting organic waste in to value-added products using microbial consortia

In the current scenario, great emphasis is being made on the recovery, recycling, and reconditioning of organic solid waste. With a focus on the bioconversion of organic waste into value-added products, municipal vegetable waste was fractionated into liquid and solid part. The solid fraction was subjected to biodegradation in the presence of different microbial consortia and different enzymes were extracted. The remaining solid stuff was converted into animal feed, followed by the evaluation of its microbiological and chemical indices. Liquid fraction separated from waste was used as a crude medium to grow different bio-fertilizer strains. Among the three consortia, consortium C (Aspergillus terreus and Myrothecium verrucaria) showed the maximum production of amylase, cellulase, xylanase and pectinase after 4 days. Results of the microbiological and chemical parameters of the animal feed prepared from the fermented vegetable waste showed that the various parameters were found to be within the permissible limit. The average concentrations of heavy metals in the compost was found to be within the permissible limit of FCO standard, therefore, it can also be used for agricultural application. For using liquid extract of the vegetable waste, maximum CFU count 1.9 × 106, 1.1 × 106, and 8.7 × 105 was achieved in BAB 1980, BAB 662, and BAB 267 strain, respectively after 30 h of incubation. Thus, the present study demonstrated the bioconversion of vegetable waste into crude enzymes, animal feed, compost, and liquid biofertilizer.

UPTAKE OF HEAVY METALS BY VEGETABLES GROWING ON SEWAGE SLUDGE

Concentrations of the investigated heavy metals in the representative samples of vegetable growing media differed significantly – the highest concentrations were in the root zone of pumpkin, and the lowest – in the root zone of tomato. Only cadmium exhibited higher concentrations in the root zone of pumpkin and zucchini exceeding maximum permissible limits according to LAND 20-2001. Concentrations of all other metals in the root zone of the investigated vegetables were below limit values valid for the 1st category sewage sludge. Mean concentrations of nitrogen, phosphorus and potassium in the root zone was quite different for the three selected plant species, but comparably high bioavailable concentrations of the primary plant nutrients showed potential for this sludge to be used in agriculture or forestry. Concentrations of Cr, Ni and Pb in the sewage sludge were far below the critical range, while Cd, Zn and Cu concentrations were within the range or even above critical soil concentration values suggested in the reviewed literature. While average heavy metal concentrations in different parts of the investigated vegetables (pumpkin, zucchini and tomato) were much lower than the suggested critical ones, and was within the range (Cu, Zn, Cr and Ni) or even lower (Cd and Pb) than normal HM level in plants. Concentration of all of the investigated heavy metals was significantly lower in vegetable fruits than in the roots and no metal accumulation in the vegetable biomass (roots as well as aboveground parts) was observed – all accumulation coefficients were below unity.

Investigation of Bioaccumulation and Human Health Risk Assessment of Heavy Metals in Crayfish (Procambarus clarkii) Farming with a Rice-Crayfish-Based Coculture Breeding Modes.

Due to the rapid development of the crayfish (Procambarus clarkii) industry in Chinese catering, people are paying more attention to the bioaccumulation of heavy metals in crayfish. To evaluate the health risks associated with the consumption of crayfish, nine types of heavy metals in both crayfish and abdominal muscles of crayfish were investigated. Crayfish samples were collected from rice-crayfish-based coculture breeding modes from different areas located in the middle and lower reaches of the Yangtze River. The average concentrations of heavy metals in the whole crayfish were much higher than the abdominal muscle of crayfish. The estimated daily intake (EDI) of heavy metals in the abdomen of crayfish was calculated to assess the noncarcinogenic risk and the overall noncarcinogenic risk including the target hazard quotient (THQ), the hazard index (HI) and carcinogenic risk (CR). The results of the present study showed that the consumption of crayfish may not present an obvious health risk to human associated with heavy metals. However, the THQ values of As in the abdominal muscles of crayfish for adults in EnShi (ES) and children in JiaYu (JY) should be of concern due to the higher contribution to the potential health risks of crayfish compared to other metals. Through X-ray photoelectron spectroscopy (XPS) detection of heavy metal As, it is found that As in crayfish culture environment mainly exists in the form of As3+.Therefore, the quality and quantity of crayfish consumption should be moderated to prevent the bioaccumulation of As. The results indicate that crayfish cultured in different areas may have similar pollution levels and/or emissions from the same pollution sources.

Characteristics and Risk Assessment of Heavy Metals in Urban Soils of Major Cities in China

The rapid urbanization in China may lead to heavy metal pollution in urban soil, threatening the health of residents. By collecting literature data published in the last 15 years, the characteristics and risks of heavy metals in the urban soils of 52 cities in China were analyzed. The results showed that the average ω(Pb), ω(Cd), ω(Cu) and ω(Zn) in the urban soils of China were 58.5, 0.49, 42.1, and 156.3 mg·kg-1, respectively, and the average Igeo values were ordered as follows Cd(1.10) > Zn(0.36) > Pb(0.28) > Cu(0.13). The high concentrations of heavy metals in the urban soils were mainly found in cities located in coastal economically developed provinces (such as Jiangsu, Zhejiang, etc.) and resource-based provinces (such as Hunan, Henan, Inner Mongolia, etc.). The cities of Kaifeng, Yangzhou, Hohhot, Taiyuan, and Xiangtan had relatively high Igeo values for heavy metals in the soils. The concentrations of heavy metals in soils from industrial areas and roadsides were significantly higher than those from residential areas and parks, suggesting that heavy traffic and developed heavy industry were the main causes of heavy metal accumulation in the urban soils. No significant correlations between the average concentrations of heavy metals in urban soil and urban economic and environmental indicators[such as permanent population, GDP, ρ (PM10), ρ(PM2.5), and SO2 emissions] were found. The concentrations of heavy metals in urban soils showed large spatial heterogeneity, and hence the average concentrations may not reflect the overall accumulation level in a city. The non-carcinogenic risks for children posed by heavy metals in urban soils were generally low, and the main risk contributor was Pb. However, the exposure to heavy metals in soils in cities with developed smelting industries is worthy of attention.

Fish diversity and heavy metal accumulation of Pb, Cu and Zn after Mount Sinabung Eruption in Benuken River, North Sumatra, Indonesia

Abstract. Pebriani MA, Barus TA, Ilyas S. 2021. Fish diversity and heavy metal accumulation of Pb, Cu and Zn after Mount Sinabung Eruption in Benuken River, North Sumatra, Indonesia. Biodiversitas 23: 187-194. The Benuken River is a river that has been affected by the volcanic ash eruption of Mount Sinabung, one of the active volcanoes in Indonesia. This study further examines the diversity of fish species and the analysis of their tissues with regard to the heavy metal content of each species in the Benuken River, Berastepu Village, Karo Regency after the eruption of Mount Sinabung using atomic absorption spectroscopy (AAS). The fish and water sampling were carried out in March 2019 with two sampling points using the electrofishing technique. Furthermore, four species were documented, including Spotted barb (Puntius binotatus), River loaches (Homaloptera nebulosa), Mahseer (Tor soro), and Striped snakehead (Channa striata). The diversity index of the fish community from two study sites ranged between 0.012<H' <0.023 or was categorized as very low in diversity. Meanwhile, the heavy metals concentrations of Cu, Pb and Zn in the water of Benuken River were below tolerance level based on the Governmental Regulations No. 82 year 2001. The average heavy metal concentrations in fish tissue were also safe for consumption based on the standard quality by FAO/WHO (2004) with 0.0049 ppm, 0.0056 ppm and 0.3852 ppm of Pb, Cu and Zn, respectively.

ASSESSMENT OF TEMPORAL VARIATION OF HEAVY METALS IN SEDIMENTS OF WARRI RIVER, SOUTHWESTERN NIGERIA

Contaminated sediment poses a serious environmental problem, therefore knowledge of the concentration of heavy metals in stream sediments is very important because of their significance to aquatic life and human health. The concentration of heavy metals (Cd, Pb, Cr, As, Ni, Zn, Fe and Cu), in stream sediments of some parts of Warri River, Southwestern Nigeria were examined during the rainy and dry seasons using Atomic Absorption Spectrophotometer, in order to assess their contamination levels using the environmental contamination indexes; Geoaccumulation Index, Enrichment Factor (EF), and Contamination Factor (CF). For both the rainy and dry seasons, the results revealed average heavy metal concentrations obtained in all samples in the study area in the order As>Cd>Pb>Ni>Cr>Zn>Cu>Fe. The trend in mean Igeo values was as follows: As (-0.66) > Zn (-4.93) > Cu (-5.8) > Fe (-5.31) > Cd (5.76) > Pb (-6.35) > Ni (11.25), showing that River Warri’s sediments were not polluted by heavy metals. Cu= Zn (0.08), Cd (0.34), Pb (0.02), As (0.01), and Ni (0.00) were the mean CF values across all measured locations, indicating a low contamination factor. The average EFs for the sediments were As (1.09) > Cd (1.10) > Cu (1.46) > Zn (1.61) > Pb (1.09) > Ni (1.09) > Fe (0.83), showing low enrichment (<2). Evaluation of enrichment factor, geo-accumulation index and contamination factor values showed that the stream sediments of the study area were unpolluted. Heavy metals in the sediments were found to be linked to anthropogenic activities in the study region, according to the results of the hierarchical cluster analysis (HCA). The metal concentrations in the sediment were found to be elevated at some sampled points, it is therefore recommended that annual monitoring of the stream sediments of the study area is undertaken. Also, sustainable practices should be employed in order to conserve the resources of the Warri River.

Heavy Metals in Agricultural Soils of National Capital Region, Delhi: Levels and Ecological Risk

This study was conducted to assess heavy metals concentrations in agricultural soils in the National Capital Region, Delhi. A total of 84 soil samples were collected from selected agricultural areas located near industries, national highways, state highways, Yamuna floodplain, residential complexes, and wastewater irrigated soils. Heavy metal concentrations, pH, and organic carbon (%) were analyzed in the collected soil samples. The average value of pH, and organic carbon (%) in the soil samples were 7.79±0.49 and 0.53±0.17 percent respectively. Average concentrations of heavy metals (mg kg-1) in the agricultural soils were found in the order of Fe > Al > Mn > Zn > Ni > Cr > Cu > Pb > Co > Cd with value as 14916.92, 13538.87, 277.16, 74.53, 35.34, 33.68, 22.94, 18.45, 1.88, and 0.92 . The concentrations of Zn, Ni, and Mn reported in the present study were several times higher than their concentration in Indian natural background soils. A significant potential ecological risk has been noticed in nearly all the agricultural soil samples except for the samples collected nearby residential areas. The contamination factor has shown that most of the soil samples were moderately contaminated with Mn, Ni, Fe, and Cr and some soil samples were considerably to strongly contaminated with Zn, Pb, Cd, and Ni. Wastewater irrigated soils showed a moderate to a strong degree of accumulation of Zn, Cd, and Ni.

Heavy Metal Levels in the Beyler Dam Lake, Kastamonu (Turkey)

In this study, some heavy metal concentrations (Cu, Cd, Pb, Cr, Mn and Zn) were seasonally determined in water to evaluate of the quality of the Beyler Dam Lake. The average concentrations of heavy metals analyzed in water samples for cold and hot season were Cu: 11.53, 13.23; Cd: 0.85, 0.97; Pb: 13.77, 16.26; Cr: 2.88, 3.48; Mn: 1.94, 1.71; and Zn: 7.57, 8.20 ppb, respectively. The annual average (AA) concentrations of heavy metals were Cu: 12.38; Cd: 0.91, Pb: 15.01, Cr: 3.18; Mn: 1.82; and Zn: 7.88 ppb. In general, the heavy metal concentrations were found to be higher in hot season than the cold season. It was observed that none of the heavy metals assessed exceeded the limits specified in the Turkish Water Pollution Control Regulation. The Beyler Dam Lake was classified as Class I for all the heavy metals except Pb for which it was classified as Class II. These results indicate that the lake is not polluted by the heavy metals. However, relatively high Pb levels seek further research to identify the source. The lake water can be used for agricultural activities but should continue to be monitored.

Assessment of the heavy metal sources and concentrations in the Nador Lagoon sediment, Northeast-Morocco

This study investigates the heavy metals (HM) and sulfurs concentration, enrichment level and potential sources in the bottom sediments of Nador lagoon, North-East Morocco. 50 samples of sediments from Nador lagoon heavy metals were analyzed by ICP-MS, while their spatial distribution and source identification were evaluated by Enrichment Factor (EF), QGis Inverse Distances Weighted (IDW) interpolation models, multivariate statistical techniques (Principal Component Analysis - Agglomerative Hierarchical Clustering - Pearson correlation matrix), Positive matrix factorization (PMF model) and grain size/organic matter analysis. The average heavy metal concentrations in the sediments are in the decreasing order: Sr > Ba > V > Zr > Zn > Cr > Rb > La > Cu > Pb > Ni > Ce > Nd > Co > Sc > Nb > Ga > Th > Y > Hf, and the Sulfurs. The results showed that the average concentrations of the S, Sr, Pb, and Nd in bottom sediments were higher than their background contents. The EF values demonstrated that HM contents were enriched by anthropogenic activities, especially for Sr and S, and secondly for Th, V, Ce, Nd, and Pb. The potential HM and sulfurs identified sources showed that: 1) Ga, Y, Hf, Nb, Rb, Sc, Zr, Nb, Co, Zn, Th, Ni, V, Ba, Cr, and Cu were derived industrial activities related to stealing and mining; 2) Wastewater treatment station and lagoon watershed were the main sources of Sr in the lagoon; 3) Zn, Cu, and Pb also linked to sulfurs, mostly origin from agriculture inputs and mining activities; 4) Ce, Cr, and Ni linked to sulfurs, mainly origin form metallurgical activities and solid wastes. The results suggest that heavy metal concentrations were significantly affected anthropogenic activities. Severe enrichment of Sr was found in the lagoon ecosystem with no correlation with carbonates, with four sources of heavy metals apportioned by Geostatistics and Positive matrix factorization. Solid waste, water waste and industrial activities were the main anthropogenic source. Lutite fraction and organic matter show a high accord with heavy metals concentration distribution.

Effects of long-term agricultural activities on the availability of heavy metals in Syrian soil: A case study in southern Syria

Agricultural soil pollution has attracted the attention of scientists and agricultural managers because of its importance to food security worldwide. In Syria, limited studies have been conducted to determine heavy metals (HMs) concentrations in arable lands. The objective of this study was to investigate the concentration of HMs in the southern part of Syria, and to identify the potential sources HMs. To achieve the study goals, 38 soil samples (0–25 cm) were collected and analysed for physical and chemical soil properties, while the DTPA (Diethylenetriamine pentaacetate) method was to extract HMs from soil. The results of this study showed that the average concentration of HMs in the study area are 2.00; 12.70; 8.56; 4.37; 0.12; and 0.12 ppm for Cu; Fe; Mn; Zn; Cd; and Pb, respectively. A multivariate statistical analysis showed that Cu, Fe, and Mn originated from parent material (natural resources), while Zn and Cd were related to agricultural activities (anthropogenic one) and Pb was relatively related to industrial activities. Interestingly, the spatial distribution indicates that Cu, Fe, and Mn distributed in the southern and eastern part of the study area, while Pb and Zn were dominant in the western and northern part. In addition, Cd was observed in the central part of the study area. We conclude that human activities are the main contributor of HMs accumulation in soil. The distribution of these HMs could affect the safety of agricultural product in the future.

Heavy Metal Concentrations and Human Health Risk Assessment of Selected Wild and Cultured Fishes of Bangladesh

This study was conducted to estimate the concentration of selected heavy metals such as chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) as well as the possible risk to consumer health from the flesh of three wild and cultured fishes (Labeo rohita, Mystus cavasius, and Heteropneustes fossilis) collected from the Meghna river, Narayangonj and Rajoir fish farm, Madaripur district respectively. Heavy metal concentrations were determined using Atomic Absorption Spectrometric method. The average concentration of heavy metals were found in the wild fish samples in the range as Cr (0.295-1.647), Mn (0.900-1.294), Ni (0.063-0.198), Cu (0.179-0.529), Zn (5.487-8.343), Cd (0.004-0.009) and Pb (0.193-0.290) mg/kg dry weight while in the cultured fish samples in the range as Cr (0.043-0.315), Mn (0.975-2.36), Co (BDL), Ni (0.005-0.095), Cu (0.238-0.978), Zn (5.487-8.305), Cd (0.004-0.009), and Pb (0.238-0.286) mg/kg dry weight respectively. The hierarchy of mean concentration of heavy metals in wild fishes was Zn> Mn> Cu> Pb> Cr> Ni > Cd and in the cultured fishes, the order was found Zn> Mn> Cr> Pb> Cu> Ni > Cd. The present study showed that the wild fish accumulated higher concentration of heavy metals in their muscles than the cultured fish. The analyzed Ni, Cu, Zn, Cd, and Pb were below the allowable level specified by international agencies (FAO, WHO, EU, CE, USEP). In order to assess the human health risk, the Target Hazard Quotient (THQ), Hazard Index (HI), and Target carcinogenic Risk (TR) were calculated. The TR values suggested that the fishes posed low to moderate carcinogenic risk from Cr, Ni and Cd. Consequently, continuous and excessive consumption of these fish species over a lifetime will increase the possibility of causing cancer. Bangladesh J. Zool. 49 (2): 189-203, 2021

Mapping heavy metals contamination and eco-risk along Mediterranean Sea coast, Egypt

The study was selected according to its variability in resources and its important location parallel to an important protectorate. This coastal zone is characterized by different land use/cover activities (water, industrial site, agricultural areas, bare land, vegetative areas, fish farms, and sabkha). Twelve sites were selected along this part of the Mediterranean deltaic coast, each distance between every site is nearly 5 km. water and sediment samples were collected for the determination of these metal ions (Fe, Mn, Zn, Cu, Ni, Pb, Cd, and Co). The average concentrations of heavy metals are 56.50, 2.53, 24.77, 4.28, 0.88, 18.37, 0.97 and 0.06 µg/l in water and 7284.58, 132.60, 13.52, 2.99, 8.36, 4.84, 0.36 and 4.32 µg/g in sediments for Fe, Mn, Zn, Cu, Ni, Pb, Cd, and Co, respectively. The concentrations of these metals (Zn, Cu, Ni, Pb, and Cd) are within the Australian guideline of marine sediments, but Zn, Cu, and Cd in water exceed these limits. Cadmium was the most abundant element in the coastal marine sediments. The heavy metal pollution index for marine water of the study area is within the normal limits except for site 12. The risk index of metals gives a low-risk category. The principal component analysis indicated that site 11 was related by dissolved Pb in seawater and Fe in sediments, this is maybe interpreted by the nature of sediment texture and different shipping activities. Mapping the spatial distribution of metals and their risk categories is an aid in monitoring environmental problems and quantifying their magnitudes.