Level Of Heavy Metal Pollution Research Articles

Using self–organizing maps and machine learning models to assess mollusc community structure in relation to physicochemical variables in a West Africa river–estuary system

The poor understanding of changes in mollusc ecology along rivers, especially in West Africa, hampers the implementation of management measures. We used a self–organizing map, indicator species analysis, linear discriminant analysis and a random forest model to distinguish mollusc assemblages, to determine the ecological preferences of individual mollusc species and to associate major physicochemical variables with mollusc assemblages and occurrences in the Sô River Basin, Benin. We identified four mollusc assemblages along an upstream–downstream gradient. Dissolved oxygen (DO), biochemical oxygen demand (BOD), salinity, calcium (Ca), total nitrogen (TN), copper (Cu), lead (Pb), nickel (Ni), cadmium (Cd) and mercury (Hg) were the major physicochemical variables responsible for structuring these mollusc assemblages. However, the physicochemical factors responsible for shaping the distribution of individual species varied per species. Upstream sites (assemblage I) showed high DO and low BOD and mineral compounds (i.e., TN, salinity, and Ca), which are primarily responsible for structuring the occurrences of bivalves (Afropisidium pirothi, Etheria elliptica, Sphaerium hartmanni) and the gastropod Lanistes varicus. Sites along the middle reach (assemblage II) were characterised by a high degree of organic pollution but low heavy metal pollution; we detected no specific mollusc indicator species. Downstream sites (assemblage III) displayed high mineral and heavy metal concentrations and a fauna without specific indicator species. Finally, downstream sites associated with brackish water (assemblage IV) displayed important levels of organic and heavy metal pollution. These sites are dominated by diverse gastropods (i.e., Bulinus spp., Gabbiella africana, Indoplanorbis exustus, Pachymelania fusca, Radix natalensis, Stenophysa marmorata and Tympanotonos fuscatus). Our results highlight that mollusc communities in the Sô River Basin are structured by key physicochemical variables related to the river–estuary continuum. Habitats that are progressively more downstream are confronted with increasing anthropogenic stress. Conservation and management plans should focus on downstream habitats.

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 pollution characteristics and health risk evaluation of soil around a tungsten-molybdenum mine in Luoyang, China

Heavy metal pollution in mining area soil and its impact on human health have been becoming one of the most important global environmental problems. This study investigated the heavy metals in the soil around the tungsten-molybdenum mining area in southwestern Luoyang, Henan Province, assessed the level of heavy metal pollution in the soil around the tungsten-molybdenum mining area, and quantified the risks of these pollutants to human health. To assess these potential threat levels, The pollution index, potential ecological hazards and health risk assessment methods recommended by the United States Environmental Protection Agency (USEPA) are applied. The results indicated that the average soil content of the heavy metals Zn, Cr, Cd and As exceeded the soil pollution risk screening value. The Nemerow comprehensive pollution index (PN) was greater than 3, which indicated severe pollution. The potential ecological risk index (RI) of each sampling point was integrated in the order $${\mathrm{RI}}_{\#7}$$ > $${\mathrm{RI}}_{\#6}$$ > $${\mathrm{RI}}_{\#5}$$ > $${\mathrm{RI}}_{\#3}$$ > $${\mathrm{RI}}_{\#4}$$ > $${\mathrm{RI}}_{\#2}$$ > $${\mathrm{RI}}_{\#1}$$ . Among the heavy metals, Cd posed the greatest ecological threat, accounting for 91.32% of RI. The effect of heavy metals in soil on the single non-carcinogenic health risk index (HQ) and non-carcinogenic total index (HI) through three exposure pathways, oral intake > skin contact > respiratory inhalation, was $${\text{HQ}}_{{{\text{Zn}}}} {\text{ < HQ}}_{{{\text{Cu}}}} {\text{ < HQ}}_{{{\text{Cd}}}} {\text{ < HQ}}_{{{\text{Pb}}}} {\text{ < HQ}}_{{{\text{Cr}}}} { < 1}$$ . The sum of $${\mathrm{HI}}_{\mathrm{Pb}}$$ and $${\mathrm{HI}}_{\mathrm{Cr}}$$ accounted for 92.96 and 92.98% of adults and children, respectively. In addition to the inhalation route $${\mathrm{CR}}_{\mathrm{Cd}}$$ , $${\mathrm{CR}}_{\mathrm{Cr}}$$ and $${\mathrm{CR}}_{\mathrm{Cd}}$$ in the study area were higher than the maximum acceptable human-level recommended by the U.S. EPA (10–6), and the CR and TCR were higher in children than in adults. Therefore, the heavy metal pollution of soils in the studied tungsten-molybdenum mine area was found to pose a serious threat to the surrounding ecological environment and residents’ health.

Research on heavy metal level and co-occurrence network in typical ecological fragile area

Due to the special sensitivity of typical ecologically fragile areas, a series of human life, mining, and other activities have a greater impact on the environment. In this study, three coal mines in Ordos City on the Loess Plateau were selected as the study area, and the pollution levels of heavy metals in the area were studied by measuring As, Hg, Cr, Cd, Cu, Ni, and Pb in the soil of 131 sampling points. Combined with the concept of “co-occurrence network” in biology, the level of heavy metals in soil was studied using geostatistics and remote sensing databases. The results showed that the concentrations of Hg, Cr, Ni, Cu, and Pb in more than half of the sampling points were higher than the local environmental background value, but did not exceed the risk control value specified by China, indicating that human factors have a greater influence, while Cd and As elements are mainly affected Soil parent material and human factors influence. Heavy metal elements have nothing to do with clay and silt but have an obvious correlation with gravel. Cd, Pb, As and Ni, Cd, Cr are all positively correlated, and different heavy metals are in space The distribution also reflects the autocorrelation, mainly concentrated in the northeast of the TS mining area and the middle of the PS mining area.

HMCA-Contour: A Visual Basic Program Based on Surfer Automation for Soil Heavy Metal Spatial Distribution and Contamination Assessment Mapping

Soil heavy metal contamination has become a major concern in many parts of the world. Grasping the spatial distribution patterns of heavy metals and evaluating soil heavy metal contamination are of great significance to policy makers for land use planning and pollution identification. However, these processes usually involve repetitive calculation and plotting, which are time-consuming and laborious, especially in a geochemical survey. In this paper, HMCA-Contour, which is a program written in Visual Basic based on Surfer 13.0, has been designed to simplify the pollution indices recalculation and plotting routines. This software is comprised of three functions, i.e., data processing, plotting, and template setting. With user-friendly interfaces, the user can easily and efficiently calculate pollution indices and generate batch publication-quality maps of heavy metal spatial distribution and pollution levels. To demonstrate the advantage of HMCA-Contour, a case study from the Gaerqin Mine area is used in this paper. HMCA-Contour, as a brand new software, is promising and will become a useful tool for environmental management.

Heavy metal pollution caused by cyanide gold leaching: a case study of gold tailings in central China.

It is known that the tailings of gold mines have brought serious heavy metal pollution; however, the heavy metal pollution caused by gold tailings in specific geological environments and extraction processes still must be studied. This study investigated the distribution, speciation, bioaccumulation, and pollution of heavy metals in soils from the Yueliangbao gold tailings area in central China, where gold was extracted by cyanidation. The results show that the concentrations of Cu, Pb, Zn, Mn, Mo, and Cd in the soils of the tailings pond were higher than those in the local background. The concentrations of heavy metals related to mineralization activities, such as Cu, Pb, Zn, and Mo, varied with the distance to the tailings pond center. There was a decreasing trend of tailings pond center > tailings pond entrance > surrounding environment. This study's gold tailings pond differed from those of other regions because of its high content of unextracted Cu remaining in the pond. The proportion of non-residual Cu in the tailing pond soil was much higher than that of residual Cu, indicating it was likely to migrate to the surrounding environment. The pollution assessment indicated that the tailings pond soils were heavily polluted by Cu, and the level of heavy metal pollution in soils was positively correlated with the distance to the tailings pond center. Consequently, this tailings pond may become a source of Cu pollution in the surrounding environment, thus endangering environmental safety and human health. The study of heavy metal concentrations in the dominant plants showed that Chinese brake (Pteris vittata L.), Ramose scouring rush (Equisetum ramosissimum), and Manyflower silvergrass (Miscanthus floridulus) had the potential to be used for the phytostabilization of Cu.

Occurrence and fate of antibiotics and heavy metals in sewage treatment plants and risk assessment of reclaimed water in Chengdu, China

Aim of this study was to provide an up-to-date assessment of the heavy metals and antibiotics in reclaimed water in Chengdu, China. 3 sewage treatment plants (STPs) and 1 constructed wetland (CW) were first taken as the research objects. The total concentration and reduction change rule of heavy metals and antibiotics in the process of reclaimed water production were investigated. The possible health risks to ecological environment and human body were evaluated. For the treatment process, the Cyclic Activated Sludge System (CASS) used in A sewage treatment plant (STP A) had the best removal effect for heavy metals. When the proportion of industrial wastewater in the influent was relatively high, the heavy metal pollution level was alert. Ofloxacin (OFX) and roxithromycin (ROX) were the most abundant antibiotics in reclaimed water. After being removed by the sewage treatment system, OFX concentrations changed, but several of them remained in reclaimed water. Negative removal of ROX occurred. This is because macrolides were wrapped in human feces, whose concentration increased as feces disperse and hydrolyze. Compared with CASS (20.02%) and Anaerobic-Anoxic-Oxic process (A2/O 34.16%), the average removal rate of antibiotics from the A2/O accompanied by Membrane Bio-Reactor (71.1%) and CW (54.95%) was higher. When the proportion of domestic sewage in wastewater was high, antibiotics in reclaimed water had higher ecological risk. OFX had the highest ecological risk for non-target aquatic organisms. It was assessed that the heavy metals and antibiotics studied did not pose a carcinogenic or non-carcinogenic risk to human health.

Heavy metal pollution assessment in paddy fields and dryland in Bandung District, West Java

Excessive use of fertilizers and pesticides causes the accumulation of heavy metals in intensive agricultural land. Besides, the development of industries around the agricultural area further aggravates the accumulation of heavy metals. This study aimed to assess spatial distribution of heavy metal contamination in agricultural land in Bandung District. In this study, seven concentrations of heavy metals (Cr, Pb, Cd, Co, Cu, Ni, and Zn) in soils were analysed from 273 sampling sites in paddy and horticultural lands in Bandung Regency, Indonesia. The single pollution index (PI) and the Nemerow Integrated Pollution Index (NIPI) were calculated for each surface sample (0-20 cm) to assess the level of heavy metal pollution. Ordinary Krigging (OK) method was used to delineate the spatial distribution of heavy metals. The results show that the average values of all PIs and NIPI values are at a safe level, except for cobalt which showing slightly polluted. The analysis showed that around 3.23 and 8.76% of soil samples were slightly contaminated with cadmium and cobalt, respectively. The finding can be used as a reference for stakeholders to manage paddy fields against heavy metal contamination.

Heavy metal pollution of road dust in a city and its highly polluted suburb; quantitative source apportionment and source-specific ecological and health risk assessment

Sources of heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in the road dust of Bandar Abbas city, Iran, and its west suburb were apportioned and the related source-specific ecological and health risks were assessed. The level of heavy metal pollution and the related ecological risk for suburban road dust (suburban RD) were far higher than those of urban RD. Accordingly, probabilistic health risk assessment showed no significant health risk in urban region but significant health risk in the suburb, especially for As with cancer risk above 10−4. Source apportionment using positive matrix factorization (PMF) identified lithogenic source (45.9%) and traffic emission (47.6%) as the main sources of heavy metals in urban and suburban regions, respectively. However, the industrial/construction activities showed the main contribution in ecological risk in both regions. On the other hand, the health risks in urban and suburban regions were mainly attributed to lithogenic source (49.7% for non-cancer risk and 36.8% of cancer risk) and traffic emission (69.4% of non-cancer risk and 46.6% of cancer risk), respectively. The sensitivity analysis showed that the Pb and As originated from traffic emission had the most impact on the non-cancer and cancer risks, respectively, in the suburb. Therefore, this study highlighted the concern about traffic emission as a critical heavy metal source in the road dust of Bandar Abbas suburb.

EDUKASI KEAMANAN PANGAN KERANG REBUS DENGAN MEMANFAATKAN BELIMBING WULUH DI KOTA BANDA ACEH

Shell is one of the sources of seafood because it contains protein and minerals. However, shells can accumulate more metals than other aquatic animals. Based on Hanum, F' s research (2017), showed that starfruit juice can eliminate Plumbum content in boiled mussels. This needs to be known by the community from the aspect of chemical safety given the high level of heavy metal pollution in waters in Aceh. The community service activity took place for 2 days at the Balee Pengajian Alue Deah Teungoh Village in Meuraxa District, Banda Aceh. The target activity is 40 residents. Based on the results of the activity it can be concluded that the counseling and demonstration of Plumbum testing has been able to improve the knowledge and skills of participants in the technique of processing boiled mussels as a favorite family snack. Starfruit is very effective to be used as a sequestrant.

Study of Pb Heavy Metal Pollution Level on Tannin Content of Seaweed (Kappaphycus alvarezii) in Bluto and Talango Sea Waters, Sumenep, East Java

Euchema cottoni or Kappaphycus alvarezii is one type of seaweeds that is widely cultivated in Indonesia. Water pollution caused by the accumulation of Pb heavy metals will affect the seaweed to grow and develop. This study is aimed to determine the tannin levels in K. alvarezii and the relationship of Pb heavy metal pollution level with tannin levels in K. alvarezii in different waters. This study used an observational experiment, and samples were taken from two different locations with 4 stations in each. From each sample in both locations, K. alvarezii was taken and was then measured for the tannin levels, water quality, and heavy metals (Pb) in water and in K. alvarezii. The results were analyzed at the Laboratory of PT. Sucofindo and the Laboratory of Testing Service Unit, Airlangga University Surabaya. The data were analyzed using a statistical test in the form of a t-test to determine the differences in samples in both waters, and a C-square test was used to determine the relationship between PB and tannin levels in K. alvarezii. The results showed that the level of Pb heavy metal pollution in the two waters did not show a significant difference due to water quality which was quite similar in both locations. Moreover, the tannin content in K. alvarezii in Bluto waters (0.053±0.004%) was higher than that in Talango waters (0.020±0.009%). Meanwhile, a t-test showed a significant difference in seaweed tannins in both waters. The relationship between Pb heavy metal pollution and tannins of seaweed in Bluto and Talango waters was that they did not affect each other, and tannin concentration was more influenced by chemical oxygen demand (COD), salinity of both waters, and the cultivation methods used.

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

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

Heavy metal distribution in particle size fractions of floodplain soils from Dongchuan, Yunnan Province, Southwest China.

The heavy metal pollution level in soils is heavily affected by the soil particle size distribution. However, the heavy metal loss during particle size extraction and the effect of calcite on the heavy metals removal in terms of the particle size are unclear. In this study, the distribution of heavy metals (Cu, Cd, Cr, Co, Ni, Zn, Pb, U, and V) was determined in five particle fractions (> 2, 2-0.25, 0.25-0.02, 0.02-0.002, and < 0.002 mm) of two soil and one sediment samples collected from the floodplain of Dongchuan, Yunnan Province, Southwest China. The sampled floodplain soils were mainly composed of gravel and sand fractions (> 97%). The concentrations of all nine heavy metals in the sampled soils and sediment increase significantly with decreasing particle sizes. The maximal loss rate of Cd and Cu reaches 54% and 8.6%, respectively, which should be considered in the process of particle size fraction extraction in soils. The removal amount and removal rate of heavy metals in solution by pure calcite ranks in the order of Pb2+ > Cu2+ > Cr6+, while the removal rate of Pb (93.13%) is much higher than that of Cu (24.56%) and Cr (10.71%), which increase with the calcite particle size decreasing. The stabilization of carbonate minerals in soils is crucial for heavy metal pollution control in floodplain soils with high carbonate concentrations in Dongchuan, China.

Pollution characteristics and risk assessment of surface sediments in the urban lakes.

The objective of the manuscript was to evaluate the concentration and distribution of nutrients and heavy metals (HMs) in the sediments of urban lakes, as well as the potential ecological risk to the lake. This paper discusses the risk assessment and its management via potential nature-based solutions (NBS), which are lessons learnt from nature. The HM pollution and potential ecological risk were evaluated using conventional geo-accumulation index (GI) and geo-accumulation vector (GV) model. So urban lakes are usually more of a source of pollution than non-urban lakes, and more widely based on the literature on lake sediment pollution assessments in China over the past 10years, 42 urban lakes, and 5 typical non-urban lakes (five representative freshwater lakes in China) were selected. The average concentrations of total nitrogen (TN); total phosphorus (TP); and Cu, Zn, Pb, Cr, Cd, Ni, As, and Hg were 2382, 712, 33.10, 118.05, 38.30, 66.40, 0.82, 32.38, 11.33, and 0.12mg/kg, respectively. The pollution levels of nutrients and HMs in sediments were evaluated using a single pollution index, a comprehensive pollution index, a ground accumulation index, a potential ecological risk index, and a sediment quality index. The evaluation results showed that the overall pollution level of urban lake sediments in China was higher than that of the selected five typical non-urban lakes, and the problem of nitrogen pollution in sediments was more prominent. There was no significant difference in the potential risk assessment of HMs between urban lakes and typical non-urban lakes, but the probability of negative biological effects was significant. The surface sediments from the estuaries of the tributaries flowing downtowns and heavy industrial parks showed high heavy metal pollution levels and potential ecological risk. The HM pollution and environmental risk assessment of the sediments from urban lakes is of great significance.

Risk assessment and ecotoxicological diagnosis of soil from a chemical industry park in Nanjing, China.

Soil pollution due to the activities of industrial parks, is becoming an increasingly serious issue, particularly throughout China. Therefore, it is essential to explore the soil pollution characteristics and its ecotoxicological effects on model species, such as higher plant species, in typical industrial areas. In this study, concentrations of heavy metals and polycyclic aromatic hydrocarbons (PAHs) were examined in the soil collected from 10 sampling sites at a chemical industry park in Nanjing, China. The pollution index was used to assess the heavy metal pollution level of soils, while the hazard index (HI) and carcinogenic risk index (RI) were calculated to assess the human health risk of soil PAHs. In addition, wheat (Triticum aestivum L.) was used as the model species to evaluate the ecotoxicological effects of polluted soil in pot experiments. Results showed that the content of heavy metals and PAHs varied greatly in soil samples, among which the heavy metal pollution at S1, S2 and S3 was the most serious. The health risk assessment of PAHs indicated that non-carcinogenic and carcinogenic values for all soil samples were below the threshold levels. Statistical analysis of the correlation between contaminated soil and toxic effects in wheat found that the significance values of regression equations were all less than 0.05 for chlorophyll content, peroxidase (POD) and amylase (AMS) activity. This indicates that the chlorophyll content, POD and AMS activity in wheat leaves could be suitable biomarkers for evaluation of the combined toxicity of multiple pollutants. This study provides a reference for future research on the risk assessment of soil containing multiple pollutants from industrial chemical parks.

Risk identification of heavy metals in well water surrounds watershed area of Pangkajene, Indonesia

ObjectiveThis study wants to evaluate heavy metals pollution and ecological risk level of well water in Pangkajene watershed area. MethodsThe total concentration of Cd, Cr(VI), Pb and Ni were determined using AAS. We used heavy metal pollution index (HPI), metal index (MI), hazard quotient (HQ) used to estimate metals pollution and ecological risk level. Pearson correlation analysis is executed to evaluate the relationship between all measured parameters. ResultThe concentration of Cd, Ni and Pb are below detection limit value. The mean concentration of Cr(VI) 0.0017±0.0006mgL−1. The mean of HPI and MI value are 3.06 and 0.06, respectively. The upstream area of Pangkajene has HQ value for Cr(VI) is higher than 1, it indicates that exposure of Cr(VI) may cause adverse effects to the ecological system and human health. ConclusionThe Cr(VI) is the main risk factor for well water contamination surrounds Pangkajene watershed area.

SEM-EDX analysis of heavy metals in anal papillae of Hydropsyche angustipennis larvae (Trichoptera, Insecta) as a support for water quality assessment

Anal papillae of caddisflies are peripheral organs responsible for osmoregulation and detoxification. Investigation of morphological abnormalities in the anal papillae of Hydropsyche angustipennis enriched with using SEM-EDX analysis (scanning electron microscopy-energy dispersive X-ray analysis), was used to assess heavy metal pollution levels in urban streams receiving surface runoff. Heavy metal ions not previously detected in water and tissue samples by commonly used methods (e.g., AAS) were detected using SEM-EDX method. Analysis of heavy metal in the anal papillae revealed the presence of 11 elements (Fe>Mo>Mn≥Al>Cu>Pb≥Ni>Co≥As≥Ti≥V). Morphological irregularities were most frequently observed in larvae from the most contaminated streams. Most of the individuals collected from streams flowing through the city center and included in the sewage system had morphological abnormalities (~70%), contrary to the reference site (~10%). In pale, normal-shaped papillae the quantity of heavy metals was almost 10 times lower compared to darkened papillae. The present study confirms that SEM-EDX microscopy is an effective method as a support of standard heavy metal bioassays, especially if there is a necessity to detect trace elements in very small amounts of the tested material.

포항산업단지 주변 지역의 미세먼지 중 중금속 성분 농도 분포와 배출원 추정

The purpose of this study was to investigate the heavy metal pollution level in Pohang Industrial Complex and nearby residential areas where various industrial activities are related. The heavy metal sampling sites were selected as Cheongnimdong, Ho-dong, Sangdae-dong, Heunghae-eup, and Gigye-myeon. Sampling was carried out for 7 days in each season by sampling for 24 hours from 09 AM to 09 AM the next day at all sampling sites during the two seasons. The analysis of this study showed that the highest concentration was shown in Cheongnim-dong and most heavy metals are within the permissible levels. The concentration of heavy metals by survey period was high in November, the fall season. As a result of analysis of heavy metal emission sources and pollution roses, many emission sources were located around Cheongnimdong and Ho-dong, and high concentration of heavy metals was shown in Cheongnim-dong. The wind direction in Cheongnim-dong was high when the southwest and west winds were blowing. Therefore, the high concentration of heavy metals in Cheongnim-dong is expected to be influenced by heavy metal emission sources located in the southwest and west.

Spatial Distribution, Contamination Assessment, and Sources of Heavy Metals in the Urban Green Space Soils of a City in North China

To study the condition of urban green space soils in the central parts of a city in North China, the spatial distribution, sources, and pollution levels of heavy metals (Cd, Hg, As, Pb, Cr, Cu, Zn, and Ni) within green space soils in the central urban districts of the city were investigated. The results showed that the soil quality was high overall. The mean concentrations of Cd, Hg, As, Pb, Cr, Cu, Zn, and Ni were 0.172, 0.202, 9.02, 34.7, 57.0, 31.2, 85.7, and 26.3 mg·kg-1, respectively. The mean concentrations of Cd, Hg, Pb, and Zn in urban soils exceeded the background value of the Beijing-Tianjin-Tangshan region. All of the samples' heavy metal concentrations were lower than the risk screening values for soil contamination of development land in the national soil environment quality standards. With respect to the spatial distribution, the concentrations of As, Cr, and Ni were higher in the northwest of the study area, the concentrations of Cd and Zn were higher in the northeast, and the concentrations of Hg, Pb, and Cu were higher in the urban core area. As for the different land use types of the soils, the concentrations of Cd, Zn, and Ni were higher in the enterprise soils, while the concentrations of Hg, Pb, and Cu were higher in park and residential soils. Assessments of soil quality showed that 97.2% of soil samples' Nemerow integrated indices were less than 1, indicating that the soils were clean. Indices of potential ecological risk for all soil samples were less than 80, indicating that they posed a slight ecological risk. Multivariate statistical analysis (correlation and principle component analyses) showed that Cu, Pb, and Hg may originate from an anthropogenic source via the painting of ancient buildings and pesticides used to protect ancient trees. Chromium may originate from natural sources via geochemical activity and soil parent material; Cr, Zn, Ni, and As were derived from mixed sources through human and geochemical activities. The receptor model was used for identification and apportionment of pollution sources of elements over the standard. The contribution rates of sources were as follows:source 2(46.1%), source 3(33.1%), source 1(17.7%), and others (3.1%) for Cd, source 1(93.0%) for Cu, source 1(52.4%), source 3(24.2%), source 2(20.0%), and others (3.4%) for Zn, source 1(56.3%), source 2(37.8%), and source 3(5.8%) for Ni. Sources 1 and 3 were anthropogenic, while source 2 was natural.

An assessment of level of heavy metals pollution in the water, sediment and aquatic organisms: A perspective of tackling environmental threats for food security.

Pollution is severely threatening the wetland habitats. Heavy metals are one among of the major pollutants in wetland habitats. The cadmium (Cd), copper (Cu), chromium (Cr), cobalt (Co), lead (Pb), mercury (Hg), nickel (Ni) and zinc (Zn), were assessed in the water, sediment, benthic species (polychaetes, mollusc and crustaceans), prawn and fishes. The assessment of heavy metals was done by using double-beam Atomic Absorption Spectrophotometer (AAS). The Hg, Cr and Co were greater in sediment, Ni and Cd were higher in polychaetes and molluscs respectively. However, the Cu and Pb greater in crabs and the Zinc was greater in fishes. The concentration of metals showed significant differences among the various sources examined (P < 0.05) except Cr (P > 0.05). The inter-correlational analysis among the metals assessed from the various sources showed that the Cr and Pb not correlated among the eight metals examined. However, the Cu and Co were correlated with Hg (r = 0.307) and (r = 0.788) respectively. The nickel was correlated with Hg (r = 0.367), Cu (r = 0.362) and Co (r = 0.432). The Zinc was correlated with the Cd (r = 0.331) and Hg (r = 0.737). However, correlation of metals among the different sources shown that the metals of polychaetes correlated with sediment r = 0.637, the metals of crabs correlated with the sediment and polychaetes r = 0.630 and r = 842 respectively, the metals of molluscs was also correlated with sediment (r = 0.636), polychaetes (r = 0.889) and crabs (r = 0.894). In addition to that the metals of prawns was correlated with the polychaetes (r = 839), crabs (r = 0.628) and molluscs (r = 0.634). The metals of fishes correlated with polychaetes (r = 0.529), crabs (r = 0.710), molluscs (r = 0.493) and prawns (r = 0.593). Indeed the multiple regression model explained that the metals of sediments influence the accumulation of metals in biotic species such as polychaetes, molluscs, crustaceans, prawns and fishes with 84% (F = 21.079; p < 0.001).The order of the heavy metals in the water, sediment and biotic species was Hg > Pb > Ni > Cr > Zn > Co > Cu > Cd. The study found that the level of heavy metals at various sources in the sanctuary is showing considerable warning and the sanctuary is required intensive assessment on various aspects of pollution since the Point Calimere Wildlife Sanctuary is supporting several species of migratory and endangered shorebirds seasonally.