Average Concentrations Of Heavy Metals Research Articles

Pollution Distribution and Ecological Risk Assessment of Heavy Metals in River Sediments from the Ancient Town of Suzhou

The contents of heavy metals (Cd, Cu, Cr, As, Mn, Ni, Pb, and Zn) in sediments from 20 representative sections of the ancient town of Suzhou were analyzed to determine the pollution degree and potential ecological risk, and pollution sources were identified. The results showed that the average concentrations of Cd, Cu, Cr, As, Mn, Ni, Pb, and Zn in river sediments from the ancient town of Suzhou were 1.1, 142.6, 90.2, 17.2, 800.1, 63.3, 199.1, and 384.2 mg·kg-1, respectively, and the proportions of sampling points that exceeded the soil background value of Jiangsu Province were 100%, 100%, 65%, 95%, 70%, 100%, 95%, and 100%, respectively. The geo-accumulation index indicated that the pollution degree of heavy metals followed the order of Pb > Cd > Cu > Zn > Cr > Ni > As > Mn. In general, high Pb pollution, moderate Cd, Cu, Zn, and Cr pollution, slight Ni and As pollution, and no Mn pollution were observed. The potential ecological risk index for heavy metals was determined to follow the order of Cd > Pb > Cu > As > Ni > Zn > Cr > Mn. Generally, Cd, Pb, and Cu presented moderate potential ecological risk, and the others presented low potential ecological risk. The average concentration of heavy metals, geo-accumulation index, and potential ecological risk index of river sediments in the northern and southern of ancient town were all higher than that of Ganjiang River and Huancheng River, indicating that the control of heavy metals should focus on the inner part of the ancient town. According to correlation analysis and principal component analysis, Cd, Cu, Cr, As, Ni, Pb, and Zn might be derived from man-made factors such as fertilizer, road aging, tire wear, exhaust emissions and so on, which Mn was mainly derived from natural factors.

Source and Health Risk Assessment of Heavy Metals in Soil-Ginger System in the Jing River Basin of Shandong Province, North China.

This study investigated the characteristics and sources of heavy metals in a soil–ginger system and assessed their health risks. To this end, 321 topsoil samples and eight soil samples from a soil profile, and 18 ginger samples with root–soil were collected from a ginger-planting area in the Jing River Basin. The average concentration of heavy metals in the topsoil followed the order: Cr > Zn > Pb > Ni > Cu > As > Cd > Hg. In the soil profile, at depths greater than 80 cm, the contents of Cr, Ni, and Zn tended to increase with depth, which may be related to the parent materials, whereas As and Cu contents showed little change. In contrast, Pb content decreased sharply from top to bottom, which may be attributable to external environmental and anthropogenic factors. Multivariate statistical analysis showed that Cr, Ni, Cu, Zn, and Cd contents in soil are affected by natural sources, Pb and As contents are significantly affected by human activities, and Hg content is affected by farmland irrigation. Combined results of the single pollution index (Pi), geo-accumulation index (Igeo), and potential ecological risk assessment (Ei and RI) suggest that soil in the study area is generally not polluted by heavy metals. In ginger, Zn content was the highest (2.36 mg/kg) and Hg content was the lowest (0.0015 mg/kg). Based on the bioconcentration factor, Cd and Zn have high potential for enrichment in ginger. With reference to the limit of heavy metals in tubers, Cr content in ginger exceeds the standard in the study area. Although Cr does not accumulate in ginger, Cr enrichment in soil significantly increases the risk of excessive Cr content in ginger.

Spatial Distribution Characteristics and Sources of Nutrients and Heavy Metals in the Xiujiang River of Poyang Lake Basin in the Dry Season

In December of 2019, a total of 114 river water samples were collected from 38 sampling sites in the Xiujiang River of the Poyang Lake Basin for three consecutive days. The temperature (T), pH, dissolved oxygen (DO), chemical oxygen demand (CODCr), five-day biochemical oxygen demand (BOD5), total nitrogen (TN), ammonia nitrogen (NH4+-N), total phosphorus (TP), and concentrations of heavy metals (Cr, Cu, Zn and As) of the samples were measured. The results showed that the average concentrations of heavy metals in the mainstream of the Xiujiang River were Cu > Zn > Cr > As, and those in the main tributary of Xiujiang River (named as the Liaohe tributary) were Zn > Cu > Cr > As, which met the class III of the Environmental Quality Standards for Surface Water in China. However, it was founded that TN and NH4+-N in some agricultural areas had not met the class III standard of surface water. Hierarchical clustering analysis grouped sampling sites into four clusters. Clusters 1, cluster 2, cluster 3, and cluster 4 corresponded to an urban industrial area, rural mountainous area, primitive mountainous area, and agricultural area, respectively. The majority of the sampling sites were classified as mountainous rural areas less impacted by human activities, while the Liaohe tributary were urban industrial areas impacted more by human activities. Principal component analysis and correlation analysis results showed that variation of heavy metals and nutrient elements in Xiujiang River is related to the heterogeneity of human activities, which is mainly affected by urban industrial and agricultural pollution, and natural environments of the river with different background values. The results obtained in the current study will potentially provide a scientific basis for the protection and management of freshwater resources and aquatic ecosystems in the Xiujiang River and Poyang Lake Basin.

Surface Water Quality in the Mantaro River Watershed Assessed after the Cessation of Anthropogenic Activities Due to the COVID-19 Pandemic

In late December 2019, the emerging disease COVID-19 was identified as a global pandemic. Countries around the world have implemented various types of blockades to stop this infection. These health measures have led to a significant reduction in air pollution. However, the impact of these measures on aquatic environments has been little analyzed. In this context, the water quality of rivers in the Mantaro River basin was evaluated using multivariate statistical methods and heavy metal contamination indices during the health crisis of the COVID-19 pandemic. Surface water samples were collected in triplicate from 15 sampling sectors at the end of the rainy season, between March and April. Concentrations of Cu, Fe, Pb, Zn and As were determined by the method of atomic absorption flame spectrophotometry. The average concentrations of heavy metals and arsenic in the rivers evaluated did not exceed the environmental quality standards for drinking water of the Peruvian, WHO and US EPA regulations, except for Pb, Fe and As in the Mantaro River and As in the Chia River. PCA presented a total variation percentage of 83.8%. The results showed a clear positive relationship between the five heavy metals and metalloids. The hierarchical cluster analysis according to Spearman's correlation generated a dendrogram where the five chemical elements were grouped in two statistically significant groups, one group conglomerating to Cu, Pb, Zn and Fe and the other group to As. PERMANOVA partition shows that the spatial effects of the sectors are strong and significant. The HPI revealed that 13.33% of the sampling sectors exceeded the critical contamination value (150). The Cd revealed low degree of contamination (<1) in 86.67% of the sampling sectors. [ABSTRACT FROM AUTHOR] Copyright of Polish Journal of Environmental Studies is the property of Scientific Investigation Committee and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heavy Metal Contamination and Ecological Risk Assessment of Overlying Water and Sediments of Nkozoa Lake (Southern Cameroon)

Examination of heavy metals (Cr, Cu, Zn, Pb, Hg, Cd and Ni) in overlying water and sediments was conducted in Lake Nkozoa, in a peripheral area of Yaoundé characterized by a high population density and rapid economic development in Cameroon. Sediment samples were collected at the entrance and near the center of the lake, using a raft and polyvinyl chloride (PVC) pipes. They were subjected to water quality parameters, heavy metals comparisons and calculations of pollution indices and ecological risks followed by statistical analysis in order to identify and estimate the sources of metal contamination in overlying water and sediments of the Nkozoa Lake. The physico-chemical parameters of water show that the pH (5 &lt; pH &lt; 6), total dissolved solids (TDS~130 g/L) and conductivity (EC~194.8 µs/cm) are below the recommendations of the WHO. The average heavy metal concentrations in sediments, except Cd, are lower than the upper continental crust (UCC) and several environmental contamination monitoring parameters, such as threshold effect level (TEL), probable effect level (PEL), and severe effect level (SEL). The sediment samples show a low heavy metal contamination degree (class 0) and low potential ecological risk (PER) level, except for Cd and Hg which have high contamination degree (class 1 to 6) and moderate PER. Matrix correlation shows that some parameters like pH, EC, Cr and TDS, Cu, Hg in water have perfect positive correlations (r = 1.00) suggesting common sources of contamination. Cluster analyses coupled with matrix data for sediments revealed that Cd is the most contaminant elements derived from anthropogenic sources.

Heavy metals assessment in water, soil, vegetables and their associated health risks via consumption of vegetables, District Kasur, Pakistan

The consumption of contaminated vegetables has a great impact on human health. Due to this fact, we conduct the study to estimate the heavy metals in groundwater, soil, and vegetables by using the atomic adsorption spectroscopy (AAS) and find out the health risk using THQ and TCR caused by using these vegetables. The mean concentrations of As (0.015–0.40 mg/L), Cd (0.02–0.029 mg/L), Co (0.31–0.38 mg/L), Cr (1.02–1.09 mg/L), Cu (2.14–2.17 mg/L), and Hg (0.01–0.04 mg/L) are high in groundwater from threshold values given by WHO. The mean concentrations of As (22.17–23.14 mg/kg), Cd (4.21–4.54 mg/kg), Cu (21.24–24.36 mg/kg), and Pb (32.12–33.48 mg/kg) are high in soil samples from threshold values given by WHO. The mean concentrations of As, Cd, Pb, Cr, Fe, Hg, and Mn values exceeded the recommended values with concentration ranges: 1.75–4.56, 0.41–0.67, 2.12–3.12, 1.44–4.56, 87.12–135.25, 2.09–2.64, and 33.41–129.32 mg/Kg, respectively. The vegetable sample’s average concentration of heavy metals was in decreasing order cabbage ˃ brinjal ˃ okra ˃ tomato. The EDI values for As, Co, and Hg calculated for both adults and children is high. The target hazard quotients (THQ) for As, Co, and Hg are greater than the threshold value by consuming vegetables, which indicated the health risk for both adults and children. Similarly, HI due to tomato, cabbage, okra, and brinjal’s consumption is ˃ 1, with HI values 8.1975, 15.3077, 8.7312, and 10.2306, respectively. This advised the possible health effect in this area by using these vegetables. Target Cancer risk (TCR) exposed the adverse cancer risk persuaded by As, Cr, and Hg as their values exceeded the normal range by USEPA by consumption of these vegetables. This study concluded that vegetables imply the total health risk on local people, and regular monitoring of heavy metals is strongly suggested in this region.

Contamination impact and human health risk in surface soils surrounding the abandoned mine of Zeïda, High Moulouya, Northeastern Morocco

The study assesses the levels of 16 heavy metals (HMs) in soils around the Zeida mine to provide information on the extent of contamination, the ecological risk of these HMs in soils, and the health risk to the residents of the Zeida village. Total metal concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS) for 20 sampling stations around the mining area. The average concentrations of HMs (mg/kg) in the study area were as follows: Ag (2.3), As (90.4), Ba (1605.1), Be (3.1), Co (11.2), Cr (57.6), Cu (33.9), Mn (499.6), Mo (6.1), Ni (23.4), Pb (1338.7), Sb (7.4), Se (1.3), Sn (11.3), Sr (596.5), and Zn (87.9). They were higher than those at the control sites. Twelve single and integrated ecological risk indices, namely Nemerow Pollution Index (PINemerow), Contamination degree (Cd), and Potential Ecological Risk (RI), were used and suggested that tailings and their nearby soils had a moderate to high contamination potential. Based on the US Environmental Protection Agency (USEPA), the carcinogenic risk, non-carcinogenic, hazard quotient (HQ), and hazard index (HI) were calculated with three routes: ingestion, inhalation, and dermal for children and adults. For both children and adults, HI for HMs was in the order: Mn > As > Co > Pb > 1 > other HMs. Mn, As, and Co were hazardous at 90% of soil sampling stations, while Pb was hazardous in tailings samples. The inhalation and dermal carcinogenic risks presented negligible to acceptable levels. The ingestion carcinogenic risk posed a significant issue for As, which tended to be serious for children at the majority of sampling sites.

Pollution Characteristics and Health Risk Assessment of Heavy Metals in the Water of Lijiang River Basin

In order to clarify the pollution levels of heavy metals in the drinking water sources of the Lijiang River Basin, surface water samples were collected from 62 sites throughout the Lijiang River during May 2019. Heavy metals, including As, Cd, Cr, Mn, Cu, Zn, Hg, Co, and Sb, in the water samples were analysed. Health risk assessments associated with these nine heavy metals were conducted using the health risk assessment model from the US EPA. The results indicated that the order of the average concentrations of heavy metals in the water samples were Mn > Zn > As > Cr > Cu > Sb > Co > Cd > Hg. No heavy metals exceeded the limit values of the drinking water health standards in China (GB 5749-2006), and the concentrations were lower than the limitations of Grade Ⅰ level in the environmental quality standards for surface water (GB 3838-2002). According to the spatial distribution, the high contents areas of As, Cr, Zn, and Sb were predominantly distributed downstream of the Lijiang River, while the high contents areas of Cd, Cu, Hg, Co, and Mn were mostly distributed in the upper reaches. Multivariate analysis indicated that Cd, Mn, Cu, and Co were primarily from agricultural production; Cr, Zn, and Sb were mainly from tourism transportation; As was predominantly from the weathering of rock parent material and soil erosion; Hg was mainly from the improper disposal of domestic garbage and atmospheric deposition. The results of the health risk assessment indicated that children were more susceptible to the threat of heavy metal pollution than adults, and the average annual risk of carcinogenic heavy metals to human health through drinking water ingestion were higher than those of non-carcinogenic metals. The maximum personal average annual health risk of Cr was higher than the maximum allowance levels recommended by the International Commission on Radiological Protection (5×10-5 a-1). The average annual risk of non-carcinogenic heavy metals (10-14-10-9 a-1) decreased in the order of Co > Cu > Hg > Zn > Sb > Mn, which were far below the maximum allowance levels recommended by the ICRP.

Heavy Metal Concentration (Pb, Cu, Cd, Zn) In Water And Sediments In Serangan Waters, Bali

Heavy metal pollution can disturb aquatic ecosystems and indicator of water quality. This study aims to determine the concentration of heavy metals (Pb, Cu, Cd, Zn) in water and sediments. This study was conducted in the waters of Serangan, South Denpasar District, Bali in June-August 2019. The research with each location taking 8 points of water and sediment sampling and measuring the quality of its waters. Water samples taken at the surface of the water as much as 330 ml and sediment samples taken as much as 500 grams. The method used is wet ashing preparation and analyzed by means of AAS (Atomic Absorbsion Spektrophotometri). The results of the average analysis of heavy metal concentrations in water are Pb 0 mg / L, Cd 0.438 mg / L, Cu 0 mg./L, and Zn 0.284 mg / L. The results of the analysis are compared with the standard quality value of sea water that the heavy metals Cd and Zn have exceeded the threshold. While the average concentration of heavy metals in sediments are Pb 17.444 mg / kg, Cd 18.093 mg / kg, Cu 113.981 mg / kg, and Zn 53.505 mg / kg. The concentration of Cd and Cu heavy metals exceeds the limits set by the ANZECC / ARMCANZ quality guidelines and the Canadian Council of Ministers of the Environment.

Health risk assessment of heavy metals in dust particles precipitated on the screen of computer monitors.

Dust is an important factor to indoor pollution that contains suspended particles and heavy metals. Since today, use of computer has become an essential part of human life. Therefore, this study aimed to compare the amount of heavy metals deposited on CRTs and LCDs and their risk assessment. Ten dust samples for each type of monitor were collected from CRT and LCD screens in accordance with the standard OSHA ID-125 and ID-206, wet filter wipe method. Concentrations of Pb, Hg, Cd, Cr, and Cu were measured by inductively coupled plasma-optical emission spectrometer. Exposure and risk assessment of these elements were estimated using USEPA's exposure parameters. The average concentrations of heavy metals in the dust on CRTs (0.82 mg/kg) were higher than LCD screens (0.69 mg/kg). Cr with 62.824% and Hg with 0.849% had the highest and lowest average concentration in both types of monitors. The non-carcinogenic risk and carcinogenicity indexes of CRT monitors were 0.0009, and 3.94 × 10-11 and for LCD monitors were 0.0008 and 2.94 × 10-11. In both monitors, ingestion is the main route to exposure with heavy metals. The average concentration of heavy metals in CRT dust. HI values for studied metals in dust of CRTs and LCDs were less than safe limit of 1. Because RI < 10-4, cancer risk of studied elements in dust can be ignored.

Arc GIS based Interpretation of Heavy Metals in Soil Samples near Coastal Areas of Badin, Sindh, Pakistan

This study was aimed to assess the severity of heavy metal contamination in eastern coastal area of Pakistan. Agriculture lands near district Badin coastal area found contaminated due to mega surface canal drain network, carrying untreated industrial and municipal effluents along with pumped saline water. Thirty-two random soil samples were collected from different coastal areas. Arc Geographic Information System was used for spatial mapping. Soil samples from coastal areas of Badin contain average concentrations of heavy metals (mg/kg) as Hg 0.247±0.207, Ni 2.622±1.107,Zn 3.121±0.929, Cu 0.059±0.066, Fe 70.447±1.163, Mn7.062±1.251, Co 0.0167±0.033,Cr0.799±0.718.

Source and risk assessment of heavy metals and microplastics in bivalves and coastal sediments of the Northern Persian Gulf, Hormogzan Province

The objectives of the current study are to investigate the concentration, biological risks, chemical speciation, and mobility of of heavy metals and also the determination of their distribution, physicochemical characteristics, and abundance of microplastics in coastal sediments and edible bivalves in the Persian Gulf, the coastal area of Hormozgan Province. Sampling points were selected considering the location of industrial, urban and Hara forest protected areas. In November 2017, a total of 18 sediment samples from coastal sediments (top 0–10 cm) and the most consumed bivalve species in the region were collected from two stations, Lengeh and Bandar Abbas Ports. The average concentration of heavy metals (except for Ni and Cd) in the sediments were lower than their average shale and the upper continental crust. Enrichment factors revealed significant enrichment of Ni, Mn, Cr, Cd and As. The fractionation of heavy metals using the Community Bureau of Reference (BCR) sequential extraction scheme indicated the high bioavailability of Zn, As, Mn, and Co. In general, the highest concentration of Mo, Cd, Pb, Zn, Cr, Cu, Mn, Hg, and Sb was detected in areas with frequent human activities including Shahid Rajaee Port, Shahid Bahonar Port, and Tavanir station. Shahid Rajaee and Shahid Bahonar Ports are the most important ports on the coast of Hormozgan province. The Risk Assessment Code calculated for the study elements indicates that As, Co, Zn, and Cu pose a moderate environmental risk a threat to the aquatic biota. Health risks of most heavy metals arising from bivalves consumption were safe, except for As which is associated with the high target cancer risk values. With reference to the type of microplastics found, they were mainly fibeours with lengths ranging between 100 and 250 μm in sediments and bivalves. Most of the microfibers found in the sediments were made of polyethylene terephthalate (PET) and polypropylene (PP), and the fibers found in the bivalves were made of PP.

Assessment of Pollution and Health Risks of Heavy Metals in Particulate Matter and Road Dust Along the Road Network of Dhanbad, India.

Background.The rise in particulate matter (PM) concentrations is a serious problem for the environment. Heavy metals associated with PM10, PM2.5, and road dust adversely affect human health. Different methods have been used to assess heavy metal contamination in PM10, PM2.5, and road dust and source apportionment of these heavy metals. These assessment tools utilize pollution indices and health risk assessment models.Objectives.The present study evaluates the total mass and average concentrations of heavy metals in PM10, PM2.5, and road dust along selected road networks in Dhanbad, India, analyzes the source apportionment of heavy metals, and assesses associated human health risks.Methods.A total of 112 PM samples and 21 road dust samples were collected from six stations and one background site in Dhanbad, India from December 2015 to February 2016, and were analyzed for heavy metals (iron (Fe), lead (Pb), cadmium (Cd), nickel (Ni), copper (Cu), chromium (Cr), and zinc (Zn)) using atomic absorption spectrophotometry. Source apportionment was determined using principal component analysis. A health risk assessment of heavy metal concentrations in PM10, PM2.5, and road dust was also performed.Results.The average mass concentration was found to be 229.54±118.40 μg m−3 for PM10 and 129.73 ±61.74 μg m−3 for PM2.5. The average concentration of heavy metals was found to be higher in PM2.5 than PM10. The pollution load index value of PM10 and PM2.5 road dust was found to be in the deteriorating category. Vehicles were the major source of pollution. The non-carcinogenic effects on children and adults were found to be within acceptable limits. The heavy metals present in PM and road dust posed a health risk in the order of road dust> PM10> and PM2.5. Particulate matter posed higher health risks than road dust due to particle size.Conclusions.The mass concentration analysis indicates serious PM10 and PM2.5 contamination in the study area. Vehicle traffic was the major source of heavy metals in PM10, PM2.5, and road dust. In terms of non-carcinogenic risks posed by heavy metals in the present study, children were more affected than adults. The carcinogenic risk posed by the heavy metals was negligible.Competing Interests.The authors declare no competing financial interests

Heavy metals, radionuclides activity and mineralogy of soil samples from an artisanal gold mining site in Ile-Ife, Nigeria: implications on human and environmental health

The Ife-Ilesha schist belt of the Nigerian Basement Complex is renowned for artisanal gold mining activities owing to the occurrence of gold-bearing eluvial deposits within and around the belt. However, gold mining operations in Ile-Ijesha axis are carried out haphazardly without consideration of probable health risks that might be posed to the miners and local community by heavy metals and naturally occurring radionuclides materials (NORMs) contents in the soil. This study was therefore conducted to determine the mineralogy, heavy metals contents and radionuclide activity of soil samples collected from a gold mining site in Ile-Ife with a view to assessing the consequential health and radiological risks. Thirty-five (35) soil samples were collected from abandoned and active excavating pits over the entire area using stainless-steel spade. The heavy metals and radionuclides concentrations and mineralogical compositions of the samples were obtained by Atomic Absorption Spectroscopic (AAS), gamma ray spectrometry and X-ray diffraction (XRD) methods, respectively. The contamination indices consisting of Enrichment Factor (EF) and Index of geoaccumulation (Igeo) were calculated from heavy metals concentrations. The sequence of the average concentrations of heavy metals in the soil samples decreases as follows: Pb (72.93 ± 4.60) > Cd (58.26 ± 3.25) > Cr (42.81 ± 3.00) > Zn (33.66 ± 2.71) > Mn (24.60 ± 1.80) > Ni (23.93 ± 2.51). The mean EF values of the measured heavy metals occurred in the order of Cr > Pb > Zn > Cd > Ni. The Igeo values of the measured heavy metals (except Pb) were less than one (< 1) revealing practically uncontaminated condition of the studied soil. The radiation dose and radiological hazard risks were estimated by employing absorbed dose, effective dose, radium equivalent, gamma index, external hazard index, excess life cancer risk and representative level. The hazard index values of all the measured heavy metals were < 1 indicating no significant non-carcinogenic effects. The average activity concentrations of 40 K, 238U and 232Th are 259.23 ± 84.20 Bqkg−1, 185.48 ± 73.31 Bqkg−1, 11.93 ± 4.68 Bqkg−1, respectively. All the radiological indices were below the world average values stipulated by the radiation monitoring bodies. The result of the XRD indicates the preponderance of quartz, and biotite, as well as subordinate amounts of plagioclase, kaolinite, ilmenite, andradite, actinolite and microcline in the soil samples, pointing to a schistose source rock, which is probably gold-bearing. The current study indicated practically low contamination of the Ile-Ife gold mining site soils by heavy metals, low radiological risk from NORMs and prospect of mineral exploration in the area if well-established procedure is followed.

Assessment of heavy metal content, distribution, and sources in Nansi Lake sediments, China.

Much attention has been paid to the heavy metal contamination of lake sediments in rapidly developing regions. In this study, heavy metal (Cd, Cr, Co, Ni, Mn, Pb, As, Cu, and Zn) concentrations in sediment surface samples and cores from the Nansi Lake were investigated to ascertain the potential sources and environmental risks of heavy metals. The average concentration of heavy metals was 0.16-16.04 times background concentrations. The enrichment factor, Tomlinson pollution load index, geo accumulation index, positive definite matrix factor analysis (PMF), and potential ecological risk index were used to assess heavy metal concentrations and explore the evolution of heavy metal sources, and result indicated that Cd reached moderate pollution levels, which is the most polluted heavy metal in the history and present, while the remaining heavy metals are at low or no pollution levels. The contribution of Cd to RI exceeded 76%, which is the decisive factor in the ecological risk of Nansi Lake. The result of ecological risk showed that the risk level for most of Nansi Lake is medium, and some areas of Zhaoyang Lake and Weishan Lake reach high levels. The PMF results showed that there are four main factors influencing heavy metal concentrations in Nansi Lake sediments, including industrial sources, fertilizers, and herbicides used in agricultural production, traffic-related emissions, and mineral mining. Among these factors, industrial and mineral mining sources were found to be the most important, and the highest contribution rate occurred in the -10cm (1960s). Although the contribution of fertilizers and herbicides is lower than that of other sources, increasing trend should be a warning sign that Cd has reached a high ecological risk level in Nansi Lake sediments.

Distribution Characteristics and Pollution Evaluation of Heavy Metals in Greenbelt Soils of Nanjing City

Concentrations and the spatial distribution of heavy metals (Cr, Cu, Zn, Pb, and Cd) in greenbelt soils in the main areas of Nanjing City, Jiangsu Province, were investigated and pollution levels were assessed using the single factor pollution index (SFPI), Nemerow integrated pollution index (NIPI), and potential ecological risk coefficient (PERC). The results showed that the average concentrations of heavy metals in greenbelt soils exceeded their background values, with the SFPI results ranked Cd > Pb > Cr > Cu > Zn, and the mean NIPI was 2.72 indicating that the greenbelt soils are moderately polluted. The PERC of each heavy metal (Cr, Cu, Zn, and Pb) was less than 10, indicating that the greenbelt soils present a slight ecological risk, while the PERC of Cd reached 97.32, indicating a strong ecological risk. The composite PERC of all heavy metals was less than 150, indicating a slight ecological risk overall. The five heavy metals showed a patchy spatial distribution, with high concentrations of Cr, Cu, Zn, and Pb in the greenbelt soils of northeast areas, and high concentrations of Cd in the southwest and northwest. Based on the results of study, Cd pollution in greenbelt soils in main areas of Nanjing City is relatively serious, which requires further attention.

Bioaccumulation of heavy metal of lead (Pb) in white shrimp (Penaeus merguiensis) on sediments in Belawan Sea Waters, North Sumatra Province

The water of Belawan Sea have a wealth of marine resources that are quite important to supporting the economy surrounding communities. This study aims to measure the content of heavy metals lead, Pb (sediment and white shrimp) and how much heavy metal of lead is accumulated by white shrimp (Penaeus merguiensis) from sediments. Lead, Pb of heavy metals in white shrimp and sediments were analyzed by using Atomic Absorption Spectrophotometer (AAS). The results showed that the average concentration of Pb heavy metals in sediments was found of 5,90-6,78 mg / kg, when the average concentration range of Pb heavy metals in white shrimp was found of 0,014-0,089 mg / kg, while the average accumulation of heavy metals Pb in white shrimp from sediments was found the value of 0,0075. The bioaccumulation value categorized was lower because the value was found below than 1. Penaeus merguiensis indicator of organisms can be used in measuring exposure to heavy metal Pb in water.

Assessment of heavy metal pollution in Yamuna River, Delhi-NCR, using heavy metal pollution index and GIS

The present study was conducted on the river Yamuna, which passes through Delhi-NCR from Baghpat to Chhainssa, a distance of about 125 km, at six sampling locations to evaluate the concentrations of heavy metals in surface water using heavy metal pollution index (HPI) approach. The river serves both urban-industrial and rural areas in the study area; hence, domestic, industrial, and agricultural wastes are being contributed greatly in the contamination of river water. The Yamuna River is one of the major tributaries of the river Ganga originated in the Himalayas and is flowing through a varied geological terrain. Metals such as iron (Fe), copper (Cu), cobalt (Co), zinc (Zn), lead (Pb), cyanide (CN), nickel (Ni), and chromium (Cr) in selected sites of Yamuna River water were determined by using atomic absorption spectrophotometer. The concentrations of Fe, Cu, Co, Zn, Pb, CN, Ni, and Cr in the river water were found to be in the range of 40–190, 50–120, 4–66, 840–1800, 2–40, 100–600, 88–253, and 35–52 μg/L, respectively. The results show that the maximum heavy metal content was found at sampling site S3 (Nizamuddin) followed by S6 (Chhainssa), S4 (Okhla), S1 (Baghpat), S5 (Manjhawali), and S2 (Pachahira). The heavy metal data was integrated in GIS environment for preparing spatial distribution maps of sampling sites. A scatter plot matrix was created to assess the pattern and interrelationships between heavy metals. The average concentration of heavy metals was recorded high, often exceeding the permissible limits for drinking of surface water prescribed by the Bureau of Indian Standards (BIS) and World Health Organization (WHO). Based on HPI (varies from 98.2 to 555.1), about 85% of the river water was classified as highly polluted; hence, it is not recommended for drinking. Overall, significant variations were observed in concentrations of heavy metals from one location to the other which may be because of toxic industrial effluents and domestic sewage wastes being added to the river water by various anthropogenic activities in the study area. The present work highlights the pollution load of heavy metals in the river Yamuna and also advocates an urgent attention towards minimizing the health risk of people residing not only along the river banks and surrounding regions but also for city population.

Concentration distribution and assessment of heavy metals in surface sediments in the Zhoushan Islands coastal sea, East China Sea

In an effort to assess the potential contamination and determine the environmental risks associated with heavy metals, 51 surface sediment samples (0–4 cm) were collected in the Zhoushan Islands coastal sea of the East China Sea (ECS). The heavy metal concentrations, grain size and total organic carbon (TOC) contents of these surface sediments were comprehensively analyzed. The results showed that the order of the average concentrations of heavy metals is Zn > Cr > Cu > Pb > As > Cd > Hg. Zn, Cr, Cd and Hg exhibit similar distribution and which derived from a common source, however, Cu, Pb and As present different distribution. The metal enrichment factor (EF) and geoaccumulation index (Igeo) values both suggest that Cu and Cd likely pose environmental risks. The results of this study could provide scientific data to authorities in charge of sustainable marine management.

Characteristics of expanded polystyrene microplastics on island beaches in the Pearl River Estuary: abundance, size, surface texture and their metals-carrying capacity.

While expanded polystyrene (EPS) microplastics have been widely recognized as one of the most important components of plastic litter in the intertidal zones of the global ocean, our understanding of their environmental fate on island beaches is insufficient. In this study, we intended to reveal that the latest EPS microplastic pollution status on 5 island beaches in the Pearl River Estuary, China, by comprehensively assessing the abundance, distribution, size, surface texture and carrying capacity of heavy metals (Cd, As, Cr, Ni, Cu, Pb, Mn, Fe, Al). High level of EPS microplastic abundance ranged from 328 to 82,276 particles m-2 was found, with the highest abundance at Guishan Island and the lowest at Dong'ao Island. Spatial distribution of EPS microplastic abundance was significantly different among different islands. EPS microplastics in the size range of 1-2 mm were the most abundant. The content of heavy metals in EPS microplastics collected on the beaches was greater than that in the new EPS products. The average concentrations of heavy metals in EPS microplastics from 5 islands are Cd (0.27 ± 0.19 μg g-1), As (5.50 ± 3.84 μg g-1), Cr (14.9 ± 8.25 μg g-1), Cu (15.0 ± 7.66 μg g-1), Ni (17.2 ± 17.6 μg g-1), Pb (24.8 ± 7.39 μg g-1), Mn (730 ± 797 μg g-1), Fe (8340 ± 4760 μg g-1), and Al (9624 ± 6187 μg g-1), respectively. The correlation between heavy metals in EPS microplastics and sediments was better than that between heavy metals in EPS microplastics and seawater. The study results indicated that EPS microplastics could act as a carrier for the transport of heavy metals, which might pose a threat to biological and human health.