Average Contents Of Heavy Metals Research Articles

Urban geochemistry of heavy metals in road dust from Cairo megacity, Egypt: enrichment, sources, contamination, and health risks

Traffic emissions, overpopulation, and poor urban planning have degraded the environmental quality of the Greater Cairo megacity. As road dust is considered the main sink of pollutants in urban environments, thirty road dust samples from six major roads were collected. ICP-OES was used to analyze the samples in order to determine the contamination grade using the pollution indices, decipher metal sources and geochemical associations using multivariate analysis, and evaluate the ecological and human health risks. The average contents of heavy metals were arranged in decreasing order: Fe (1181.12), Zn (201.36), Pb (66.10), Ni (32.42), Cu (26.07), Cr (26.00), Co (14.78), As (2.76), and Hg (0.93) mg/kg. The spatial pattern showed that new urban communities exhibited lower contamination levels compared to unplanned old districts, especially for traffic elements (Pb, Zn, and Cu). The highest Igeo mean value was observed for Hg (3.34) followed by Zn (1.34), Pb (1.24), Ni (0.10), As (− 0.19), Co (− 0.24), Cu (− 0.73), and Cr (− 1.05). Additionally, CF values indicated very high contamination levels for Pb and Zn, whereas the highest PLI value was observed at Ramses Street. All EF values were higher than 1.5, indicating the anthropogenic enrichment of metals. RI values classified Cairo as a region with considerable ecological risk, observing that Hg was the main contributor. Correlation analysis and PCA showed that Pb and Zn originated from vehicle exhaust, Hg, Cu, and As from domestic and industrial activities, and Fe and Co from natural origin. Cr and Ni exhibited potential carcinogenic risks for children through ingestion; conversely, the non-carcinogenic risks were within safe levels. As a result, the use of clean energy is recommended to mitigate the accumulation of heavy metals in road dust and to improve the quality of life.

Health risk assessment of heavy metals based on source analysis and Monte Carlo in the downstream basin of the Zishui

In this study, stone coal mines in the lower reaches of the Zijiang River were adopted as the research object. To analyze the spatial distribution, sources, and health risks of heavy metals in the surrounding soil of stone coal mines, 82 topsoil samples were collected in the study area, and the contents of 8 heavy metals including Cd, Hg, As, Cr, Pb, Cu, Ni, and Zn were determined. The spatial distribution of heavy metals was analyzed using ArcGIS, and the pollution sources of heavy metals were identified using Positive matrix factorization (PMF). Then, Monte Carlo and health risk assessment models were used to evaluate the health risks of different populations. The results showed that the average content of heavy metals followed the order of Zn > Cr > Pb > Cu > Ni > As > Cd > Hg, and the contents of all heavy metals were higher than the soil background values of Hunan Province. The high-value areas of heavy metals content were mostly concentrated in the central region close to areas with a notable concentration of stone coal mines. PMF identified four pollution sources, namely, mining activities (26.9%), atmospheric deposition (18.8%), natural sources (32.8%) and agricultural sources (21.5%). The carcinogenic and non-carcinogenic risks for children were higher than those for adults, with As and Cd posing higher carcinogenic risks to children. Based on the source of health risks, it was determined that the health risks could be primarily attributed to agricultural sources, and As was the main heavy metal causing health risks. This study provides theoretical support for treating heavy metal pollution in mining basins.

To the study of the features of the heavy metals deposition in the mosses of the Samara region

The features of the deposition of heavy metals by mosses from the atmosphere in the identified background area (Krasnosamarsky forest) for the Samara region were studied. Pleurozium schreberi showed the highest metal accumulating capacity, Brachythecium salebrosum - average, Dicranum polysetum - the lowest. Climacium dendroides showed high species specificity in the accumulation of heavy metals among the studied species, which may be related to its water regime. A comparative analysis of the chemical “fingerprint” of the average content of heavy metals for the mosses of the Krasnosamarsky forest area according to to Markert revealed a negative deviation from the average content of heavy metals in the bryophytes of the Samara region, which meant that there were no atmospheric sources of heavy metal pollution in the study area. Mosses growing in the Krasnosamarksky forest can be used as reference species for the region. The revealed increased level of accumulation of a number of elements (Cr, V, Co, Ni, As, Fe, Zn) demonstrated the biogeochemical features of the Samara region in comparison with the reference moss species Pleurozium schreberi in Western Europe. This also indicates the need to use indicators of species growing in the region as reference values.

Pollution Characteristics and Source Analysis of Heavy Metals in Soils in Yellow River Cultural Park Based on APCS-MLR and PMF Receptor Model

With open spaces and good ecological environments, urban parks have become the first choice for the leisure and entertainment of many people. Therefore, the quality of park soil environments has gradually attracted the extensive attention of scholars. In this study, we take the Yellow River Cultural Park, a typical human disturbance area in the lower reaches of the Yellow River, as the research area to discuss the characteristics and sources of heavy metal pollution in the soil. Thirty-three soil surface samples were collected from the Yellow River Cultural Park, and the contents of seven heavy metals (Cr, Ni, Cu, Zn, Cd, Pb, and As) were determined using an inductively coupled plasma emission spectrometer (ICP-AES) and an inductively coupled plasma mass spectrometer (ICP-MS). The geo-accumulation index and geo-statistics method were used. Meanwhile, the absolute factor analysis-multiple linear regression (APCS-MLR) receptor model and positive matrix factorization (PMF) analysis model were employed to reveal the sources of soil heavy metals. The results showed that the average contents of heavy metals (Cd, Zn, Cu, Pb, and As) in the surface soil of the study area were 4.62, 1.78, 1.41, 1.08, and 1.03 times higher than the background values of soil elements in the tidal soil area of the lower reaches of the Yellow River, respectively. Except for Zn, the contents of other elements were lower than the corresponding values of soil elements in different regions along the Yellow River Basin. Among the seven heavy metal elements, the coefficients of variation of Cd and As were greater than 50%, showing obvious spatial variability. The decreasing trend of the accumulation index of the seven elements was Cd>Zn>Cu>Ni>Pb>As=Cr, and the element Cd belonged to the middle pollution category, which was obviously accumulated in the surface soil. The spatial distribution of heavy metals in the soil differed:the high contents of Cr, Cu, and Ni were distributed in the southwest and northeast, and the high-value areas of Cd and Pb were consistent with the areas of human activity intensity. The high-value areas of Zn and As were located in the center of lacustrine sediments. The combined results of the APCS-MLR and PMF models suggested that the first pollution source of soil heavy metal elements in the Yellow River Cultural Park could have been a natural source, the second pollution source may have been a transportation source, and the third source of pollution was judged as a mixed source. Human activities such as transportation sources and mixed sources were the main sources of heavy metal soil pollution, and Cr, Cu, and Ni were affected by natural factors. The contribution rates of APCS-MLR were 46.67%, 24.11%, 16.12%, and 13.10%, respectively, and the contribution rates of PMF were 35.50%, 35.48%, and 29.02%, respectively. This research can provide a basis for improving the ecological environment quality of the park and improving the health level of the population and can also provide support for the ecological environment risk management and comprehensive management along the Yellow River.

The Study of the state of soil cover of the coastal zones of the Caspian Sea, subject to the influence of climatic and anthropogenic factors

This article is dedicated to research of climate impact change and human activity on ecosystems. It is expressed as metals which is called heavy pollution. It covers the coastal territory of northwestern regions of Apsheron. Pollution in the coastal regions of the Caspian Sea with toxic substances, is of great concern, periodic studies of these zones for the presence of heavy metals are necessary. For the first time, a comparative analysis of the content of heavy metals in the territories of the northwestern part of the Absheron was carried out and the hypothetical reasons for their accumulation were presented. The studied soils in the northwestern part of the peninsula were grouped the degree of the density of heavy metals. Zinc (78.62 mg/kg, at a depth of 0–20 sm) copper and cadmium (23.65 mg/kg and 0.92 mg/kg at a depth of 0–20 sm). The concentration of zinc and copper in the northwestern direction of Apsheron by 1.18 and 1.57 times, compared with the allowable norms for clarks. Under the impact of flooding of coastal zones by the waters of the Caspian Sea, the average content of heavy metals, Ni, Cd, Pb in flooded soils at a depth of 0-100 sm increased by 1.7 times.

Heavy metal content in duck eggs and meat that consumes feed containing Sapu-sapu fish (Hypostomus plecostomus)

Abstract. Asnawi. 2023. Heavy metal content in duck eggs and meat that consumes feed containing Sapu-sapu fish (Hypostomus plecostomus). Biodiversitas 24: 3201-3206. This study aimed to evaluate heavy metals in the eggs and meat of ducks feeding on the Sapu-sapu fish (Hypostomus plecostomus Linnaeus, 1758) on Lombok Island, West Nusa Tenggara, Indonesia. The observation of collected Sapu-sapu fish samples from three major Mataram rivers. Duck eggs and meat were collected from a livestock group that fed Sapu-sapu fish. The observed variables include; macronutrients (moisture content, crude protein, crude fat, crude fiber, and ash) and heavy metal content (Cu and Pb) in the Sapu-sapu fish, duck meat and eggs fed by Sapu-sapu fish. The study found that the Sapu-sapu fish possesses complete macronutrients, making it a possible duck feed. The heavy metal content of copper (Cu) in the Sapu-sapu fish ranges from 189.314±0.0238 ppm, while the lead (Pb) content ranges from 4.25±0.18 ppm. The average heavy metal content of Cu in the eggs and meat of ducks consuming Sapu-sapu fish was 7.692±2.158 ppm and 14.523±6.481 ppm, while the levels of lead in eggs and meat of cesarean fish were 0.936±1.557 ppm 0.373±0.211 ppm. The study concluded that the Sapu-sapu fish in the Mataram city stream has a complete nutritional content (protein, fat, amino acids, minerals) but contains high heavy metals. Therefore, if consumed, ducks dispose of it into the eggs and duck meat. As a result, the eggs and meat of ducks that consume sapu-sapu fish contain heavy metals Cu and Pb that exceed the threshold, so they are unsafe for human consumption.

Analysis of the content of heavy metal ions in the coastal zones of the northern part of the Apsheron peninsula

The article is devoted to studies of heavy metal pollution of the soil cover of the coastal zones of the northern part of the Apsheron Peninsula. Pollution of the coastal zones of the Caspian Sea, serving to a greater extent as a recreational area for the population, by toxic substances is of great concern and to solve this problem, periodic studies of these zones for the presence of heavy metals are necessary. For the first time, a comparative analysis of the content of heavy metals in different areas (Buzovna, Sumgait, Novkhany) of the northern part of the Apsheron peninsula was carried out and the presumable causes of their accumulation were outlined. The researched soils in the northwestern and northeastern part of the peninsula were grouped according to the degree of concentration of heavy metals depending on the depth of the researched soils. Zinc (77.0 mg/kg, at 0–16 cm depth, transect № 03), copper, and cadmium (88 mg/kg and 0.36 mg/kg at 0–20 cm depth, transect № 05) had the highest concentrations relative to other trace elements. Concentrations of zinc and copper in the northwestern direction of the peninsula increase by 1.5 and 3–3.5 times, respectively, as compared with the generally accepted norms. Average content of heavy metals, especially Ni, Cd, Pb in flooded soils at the depth of 0–100 cm increased 2.7 times on average as a result of coastal flooding by waters of Caspian Sea. The value of total heavy metals reaches a maximum in the northwestern direction.

Pollution threshold assessment and risk area delineation of heavy metals in soils through the finite mixture distribution model and Bayesian maximum entropy theory

Pollution threshold and high-risk area determination for heavy metals is important for effectively developing pollution control strategies. Based on heavy metal contents in 3627 dense samples, an integrated framework combining the finite mixture distribution model and Bayesian maximum entropy (BME) theory was proposed to assess pollution thresholds, contamination levels and risk areas in an uncertain environment for soil heavy metals. The results showed that the average heavy metal contents were in the order Zn > Cr > Pb > Cu > Ni > As > Cd > Hg, with strong/moderate variation, and the corresponding pollution thresholds were 158.39, 84.29, 47.84, 49.75, 28.95, 18.01, 0.49 and 0.16 mg/kg, respectively. The thresholds were consistently greater than the Zhejiang Province backgrounds but lower than the national risk screening values, except for Cd. Approximately 27.9% of the samples were classified as contaminated at various levels, and they were distributed in the northern, northwestern and eastern regions of the study area. Additionally, 3.73%, 5.34% and 8.22% of the total area were classified as at-risk areas under confidence levels of 95%, 90% and 75%, respectively, through BME theory. The findings provide a reasonable classification system and suggestions for heavy metal pollution management and control.

Assessment of heavy metal levels in roll-your-own cigarette and water pipe tobacco blends

The increased consumption of roll-your-own (RYO) cigarettes and water pipe (hookah), both globally and in Bulgaria, necessitated the current investigation aimed at the assessment of heavy metal levels in the tobacco blends used in those products. The concentrations of Mn, Zn, Cu, Cd, Pb, and Ni were determined by AAS in five brands of RYO tobacco (R1-R5) and seven brands of water pipe tobacco (W1- W7), all distributed on Bulgarian market. The average heavy metal contents (mg/kg) in the two types of tobacco blends, RYO and water pipe, respectively, were as follows: Mn - 214.20 and 37.89; Zn - 31.90 and 134.87; Cu - 12.06 and 10.07; Cd - 0.80 and 1.33; Pb - 1.60 and 3.57; Ni - 1.36 and 0.80. RYO cigarette tobaccos contained higher concentration of Mn, Cu and Ni, while water pipe tobaccos - Zn, Cd and Pb. Strong correlations were found between Cu and Zn (r=0.81), Cu and Cd (r=0.90) in RYO tobacco blends, and between Cu and Zn (r=0.86) - in water pipe blends, respectively. The results from the study give reason to recommend that this information be provided to the consumers, who consider the regarded tobacco products as a safer alternative to conventional cigarettes.

Spatial distribution characteristics and evaluation of soil pollution in coal mine areas in Loess Plateau of northern Shaanxi

The ecological environment in Loess Plateau of Northern Shaanxi is fragile, so the soil pollution caused by the exploitation of coal resources cannot be ignored. With Shigetai Coal Mine in Loess Plateau of Northern Shaanxi as the object of study for field survey and sampling, the content of heavy metals in soil is analyzed, the environmental pollution in the research area is evaluated by the single factor pollution index method, comprehensive pollution index method and potential ecological risk index method, and the spatial distribution characteristics of heavy metals are discussed by the geostatistics method. According to the study results, the average contents of heavy metals Hg, Cd, Pb and Cr are 2.03, 1.36, 1.11 and 1.23 times of the soil background values in Shaanxi Province respectively and the average contents of other heavy metals are lower than the soil background values in Shaanxi Province; Hg and Cd show moderate variation while As, Pb, Cr, Zn, Ni and Cu show strong variation; the skewness coefficients and kurtosis coefficient of Cd, As and Cu in the soil within the research area are relatively high, and these elements are accumulated in large amounts. Single factor pollution index (Pi) and potential ecological risk index (E) indicate that heavy metal Hg is the main pollution factor and mainly distributed in the east and north of the research area. The comprehensive index of potential ecological risk (RI) of the research area is 1336.49, showing an extremely high ecological risk, and the distribution characteristics of potential ecological risk are consistent with that of potential ecological risk index (E) of Hg. The results of ecological risk warning show that Hg is in a slight warning status, while Cd, Pb and Cr are in a warning status. The areas with high ecological risk warning values are mainly distributed in the east and north, and the whole research area shows relatively obvious zonal distribution law. The soil is disturbed greatly during the coal mining, so the ecological governance of the mine area shall adapt to the local natural conditions and regional environmental characteristics and follow the principle of “adjusting governance measures based on specific local conditions and classifications”. An environmentally sustainable governance manner shall be adopted to realize the protection of the ecological environment and high-quality development of coal resources.

Analysis of Heavy Metals in Water and Sediment in Singkep Island Coastal Waters

Analysis of the content of heavy metals Cu, Pb and Zn in seawater, sediment and snails (C. obtusa) in Singkep island was held on June – July 2022. All parameters measured water quality is still within tolerable limits for the survival of the aquatic organism . Samples of sea water, sediment and snails (C. obtusa) were taken from five stations with three replicates at each station. Heavy metals were analyzed in the KLH Pekanbaru laboratory using an Atomic Abortion AA-7000 Shimadzu spectrophotometer. The results showed that the average content of heavy metals in Singkep waters was 0.0724 mg/l (Cu), 0.1285 mg/l (Pb)) and 0.11525 mg/l (Zn), the sediment was 10.7513 ug/g (Cu ), 25.7750 ug/g (Pb) and 34.1493 mg/g (Zn). Simple linear regression analysis indicates negative correlation between metals content in seawater and in sediment with Y = 12.864 –29.178X, r = 0.1616 (Cu), Y = 26.181 – 3.1564X, r = 0.0632(Pb) ; and Y=45.479 - 61.286X, r = 0.2689 (Zn).

Determining heavy metal pollution in sediments from the largest impounded lake in the eastern route of China's South-to-North Water Diversion Project: Ecological risks, sources, and implications for lake management

The eastern route of the South-to-North Water Diversion Project (ER-SNWDP) is a major human health project designed to alleviate the water scarcity in the Beijing-Tianjin-Hebei region in China. Impounded lake water security is directly related to the water diversion project effectiveness. At present, there is not a thorough understanding of the sediment heavy metals in Lake Hongze, the largest impounded lake of the ER-SNWDP. Consequently, this study reports a distribution analysis of Cu, Zn, Pb, Cr, Cd, As, Hg, and Ni in 101 sediment samples from Lake Hongze; we, utilized the enrichment factor, geoaccumulation index, and potential ecological risk index for the are to determine the ecological risk of heavy metals. The heavy metal source was examined with correlation analysis and principal component analysis–multiple linear regressions. The results showed that the average heavy metal content (Cu, Zn, Pb, Cr, Cd, As, Hg, Ni) were 0.03–1.57 times greater than the Jiangsu Province background values. Cd, As, and Hg were the main contributors to the Lake Hongze ecological risk. Spatially, the open water area was the most polluted among the four lake parts, and most of the flushing area had a low ecological risk. Chengzi bay and the western lake area have similar risk profiles, but are lower than the open water area risk. Source analysis showed that nonpoint-source agricultural pollution and industrial production were important pollution sources, while a considerable portion of the heavy metal content came from atmospheric deposition and natural sources. This study identified the main contamination areas and revealed the possible sources of each heavy metal; as such, this study can serve as a reference for the remediation and management of Lake Hongze to ensure the water safety of the ER-SNWDP.

Distribution characteristics and potential ecological risk assessment of heavy metals in soils around Shannan landfill site, Tibet.

At present, sanitary landfill is mainly used for domestic waste treatment in Shannan City, Tibet. However, there are few studies on heavy metals in the soil around the landfill in Shannan city. Therefore, the surrounding soil of Luqionggang landfill in Shannan City, Tibet Autonomous Region, is taken as the research object. In the study, the geo-accumulation index method, Nemerow comprehensive pollution index method and potential ecological risk index method are mainly used to evaluate the pollution and risk of heavy metals in the soil around the landfill site. The main results are as follows: The average pH value of the soil around the landfill site is 9.37, belonging to the strong alkaline range. The average values of heavy metals Hg and Ni in soil exceeded the background content, and the average contents of other heavy metals Cu, Pb, Zn, Cr, As and Cd did not exceed the background content. The average content of these eight heavy metals did not exceed the screening value of the national soil environmental quality standard. In the horizontal direction, the average content of heavy metal elements Cu, Cr, Cd, Hg and Ni is relatively high in the west. The average content of heavy metals As, Zn and Pb in the north, east and south is slightly higher than that in the west. And the farther away from the landfill, the less the soil is affected by heavy metals. The evaluation results of geo-accumulation index show that heavy metal Hg is the most affected. The average value of the comprehensive pollution index is 2.969, which is between 2 and 3, belonging to the moderate pollution level. And the west side of the landfill (downstream area) is greatly affected. The evaluation results of potential ecological hazard pollution index show that the potential risk index of single pollutants of heavy metals Cu, Pb, Zn, Cr, Ni, As and Cd belongs to low ecological hazard level, and the potential risk index of single pollutants of heavy metal Hg belongs to relatively heavy ecological hazard level. On the whole, the total potential risk coefficient belongs to medium pollution hazard degree. According to the correlation analysis, there is no significant correlation between heavy metal elements As and Hg and the other six heavy metal elements. In addition, the pollution source of heavy metal As may be mainly soil forming factors and the pollution source of Hg may be mainly human factors.

Assessment of Heavy Metal Uptake in Potatoes Cultivated in a Typical Karst Landform, Weining County, China.

The average content of heavy metals in Weining soil of karst landforms is generally higher than that of other agricultural regions. The aim of this study was to evaluate the heavy metal content in potatoes from Weining county and to analyze the correlation between the content of heavy metals in potatoes planted in the soil of karst landform and the soil’s environmental factors (soil heavy metals, soil pH, soil organic matter, altitude). Weining county (Guizhou province, China) is a typical karst landform, and has a potato production yield of 2.7 million tons. In this study, 56 soil and potato samples were collected from Weining county and the heavy metal content in the soils and potatoes was detected by inductively coupled plasma atomic mass spectrometry (ICP-MS). The content of Cr, Ni, and As in the soil was found to be higher, with almost half of the samples exceeding the maximum allowable levels. A total of 9 of the 56 samples tested had pollution load index values greater than 1.0, which indicates serious soil pollution. It was found that the ability of the potato to absorb heavy metals from the soil was very low, with the average bio-concentration factors of the metals Zn, Cu, Pb, Cr, Ni, and As being 0.087, 0.088, 0.0028, 0.0034, 0.0066, and less than 0.001, respectively. The content of the six heavy metals in the potatoes were all lower than the maximum permissible limit. The results show that a high As content in the soil could increase the content of Pb in potatoes, that a lower pH was beneficial to the bioaccumulation of Cr and Ni in potatoes, and that a high altitude is detrimental to the bioaccumulation of zinc and copper in potatoes. The HRI ranged between 1.12 × 10−2 and 5.92 × 10−2.

Geochemical Speciation, Risk Assessment, and Sources Identification of Heavy Metals in Mangrove Surface Sediments from the Nanliu River Estuary of the Beibu Gulf, China

To better understand heavy metal pollution and the potential ecological risk of mangrove sediments in the Nanliu River estuary, the speciation and distribution characteristics of heavy metals Fe, Mn, Zn, Co, Ni, Cd, Cr, Cu, and Pb in 13 surface sediments in the study area were determined and analyzed using a modified four-step BCR extraction method, and the ecological risk of heavy metals was assessed using the Geo-accumulation Index (Igeo), Potential Ecological Risk Index (RI), Risk Assessment Code (RAC), Pollution Load Index (PLI), Individual contamination factors (ICF) and Global contamination factor (GCF) methods, and source analyses were performed using correlation analysis and cluster analysis. The results showed that the heavy metal was in the order of Fe > Mn > Cu > Zn > Cr > Pb > Co > Ni > Cd. Except for Fe, Zn, Ni, Cr, Pb, and Co, the average heavy metal content of Mn, Cd, and Cu all exceeded the environmental background value; the Fe, Zn, Co, Ni, Cr, Cu, and Pd are mainly in the residual speciation, while Mn and Cd are mainly weak acid extraction and oxidation, respectively, both of which are predominantly in unstable speciation and are easily released into the environment. Mn and Cd pose a substantial ecological risk, while Cu and Pb present a moderate risk and require precaution. The source analysis results indicate that Fe, Mn, Zn, Ni, Cr, and Pb are most likely to originate from natural sources and the transportation industry, Co and Cu are likely to be mainly from ship manufacturing industrial activities, and Cd is likely to be mainly from agriculture and aquaculture. The GCF and PLI results show that places with high heavy metal enrichment and ecological risk are primarily located in areas with high industrial, agricultural, or human activity impacts.

Accumulation of heavy metals Pb and Hg in feather shells (Anadara antiquata) in Lekok Coastal Waters, Pasuruan Regency

This research is a quantitative descriptive study that aims to determine the heavy metal contamination of Pb and Hg. Sampling was carried out exploratively in the waters of Lekok Beach, Pasuruan Regency. The data obtained were analyzed by descriptive analysis by comparing the quality standards of the Minister of Environment Decree No. 51 of 2004. And analyzed by correlation test to determine the relationship between the content of heavy metals Pb and Hg in seawater and sediment with feather shells. The results of this study indicate that shellfish (Anadara antiquata) can accumulate heavy metals Pb and Hg. The average accumulation of heavy metals Pb and Hg in Anadara antiquata was 2,315 ppm and 1,100 ppm. The average heavy metal content of Pb and Hg along the sea waters of the Lekok coast are 0.204 ppm and 0.073 ppm. In the sediment the average metal content of Pb and Hg is 5.318 ppm and 1.215 ppm. The heavy metal content has exceeded the quality standard limit that has been determined by the Decree of the Minister of the Environment No. 51 of 2004 and RNO, so that it can be harmful to human health who consume shellfish. The results of the correlation test showed that there was a positive correlation between the heavy metal content of Pb and Hg in sediment and seawater and the heavy metal content of Pb and Hg in shellfish.

Analysis of heavy metal content and microbiological quality of fish and giant prawns chatch in Percut Watershed, Percut Sei Tuan District, Province of North Sumatra

The purpose of this research was to determine the content of heavy metals and microbiological quality, and compare to the requirements of the quality standard values according to SNI 2729:2013 and SNI 2705:2014, as well as to determine the value of the Bioaccumulation Factor (BAF) and the maximum consumption limit of fish and giant prawns heavy metal-concentrated. This researh used survey and random sampling methods, i.e taking research samples (tilapia, broom fish, and giant prawns) at 3 (three) observation stations, including Station 1 Amplas, Station 2 Denai, and Station 3 Percut. Heavy metal content (Pb and Cd) and microbiological quality (E.coli and Salmonella, sp) were analysed. Data analysis was done by inference and calculated using Microsoft office Excel (Microsoft Inc., USA) descriptively. The results showed that all samples in each observation did not meet the quality standard value requirements according to SNI 2729:2013 and SNI 2705:2014. The average heavy metal content of Lead (Pb) was 0,3 mg/kg in tilapia and broom fish, and 0,5 mg/kg in giant prawns. The content of heavy metal Cadmium (Cd), were 0,1 mg/kg in tilapia and broom fish, and 0,5 mg/kg in giant prawns. All samples also showed positive in containing E.coli and Salmonella, sp. The value of Bioaccumulation Factor (BAF) of heavy metals (Pb and Cd) in all samples was 1, meaning that the sample's ability to accumulate heavy metals (Pb and Cd) was high. The maximum limit for consumption of concentrated samples of heavy metals in tilapia was 0,196 kg/week, broom fish was 0,221 kg/week, and giant prawns was 0,203 kg/week.

Pollution Properties and Ecological Risk Assessment of Heavy Metals in Farmland Soils and Crops Around a Typical Manganese Mining Area

In order to assess the ecological risks of heavy metals and explore the pattern of heavy metal migration between farmland and corresponding crops in a typical and closed manganese mining area in Hunan province, farmland soils and crops surrounding the mining area (pollution area) and away from the mining area (control area) were collected, and then the contents of Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb were analyzed. The sources and distribution of heavy metals in farmland soils were analyzed using Kriging spatial interpolation and principal component analysis, and the ecological risk was evaluated using the single factor index, comprehensive pollution index, and potential ecological risk index. The results showed that the surrounding farmland soils in the closed Manganese mining area presented serious pollution of Cd, Zn, As, and Mn, in which the average contents of the above heavy metals in the dry land soil in the polluted area were 6.22, 612.28, 37.72, and 1506.2 mg·kg-1, respectively. Compared with the soil risk screening value of agricultural land, the over-standard rates of Cd, Zn, and As were 88.41%, 94.20%, and 84.06%, respectively, and the average content of Mn in the farmland soil was three times that of the background value in the Hunan soil; however, the heavy metal pollution in the paddy field was relatively light. The principal component analysis showed that the sources of Cd, Mn, and Zn in the farmland soil were related to the manganese ore mining, whereas the source of As in the farmland soil might originate from agricultural activities. The pollution area was at a heavy pollution level, and the main pollution factors were Cd, Mn, and Zn. The Cd in the farmland soil could pose a strong potential ecological risk, but the rest of the heavy metals presented only a slight potential ecological risk. The content of Cr, Pb, and Cd in the crops in the study area exceeded the standard, and the exceeding standard rate was between 1.1% and 37.3%, where the average content of over-standard heavy metals in corn was higher than that in rice, and the average content of heavy metals in leafy vegetables was higher than that in root vegetables. The soil pollution degree of heavy metals could affect the accumulation ability of crops, and different crops had different accumulation abilities. For instance, leafy vegetables and root vegetables easily accumulated Cd and Zn; however, rice and corn separately enriched Cd and Cr, as well as Zn and Cu. The contents of heavy metals in dryland soils had a positive correlation with the content of heavy metals in corresponding crops. The contents of Cd and As in the paddy field and rice presented a positive correlation, but the remaining six heavy metal contents in rice (i.e., Cr, Mn, Ni, Cu, Zn, and Pb) did not correlate with the content of the paddy fields.

Distribution Characteristics and Sources of Heavy Metals in Atmospheric Deposition During Heating and Non-heating Period in Lanzhou

Six sampling sites were set up in Lanzhou City, and atmospheric deposition samples were collected from April 2010 to March 2018. Subsequently, the concentration of heavy metals (Fe, Mn, Zn, Pb, Cr, Cu, Ni, and Cd) was determined to explore the temporal and spatial characteristics of heavy metals. Finally, partial correlation analysis, the enrichment factor method, and the principal component analysis method were used to identify the source of heavy metals in the atmospheric deposition. The results show that the ranking of average heavy metal content in the atmospheric deposition in Lanzhou from high to low was Fe > Mn > Zn > Pb > Cr > Cu > Ni > Cd, and Cd, Zn, and Pb were all polluted. In terms of time, except for Fe and Mn, the other elements mostly showed a trend of higher content in the heating period than that in the non-heating period, and the contents of each element in the non-heating period and the heating period in 2011 and 2013 were significantly different. In terms of sites, there were certain differences between the non-heating period and the heating period in each region; however, the differences among elements were not significant except for Zn and Cd. The source analysis results show that in the non-heating period, the heavy metals in the atmospheric deposition in Lanzhou mainly came from industrial sources, followed by traffic sources and fugitive dust sources. In the heating period, the heavy metals in the atmospheric deposition in Lanzhou mainly came from coal-burning, transportation, and industry activities, followed by secondary dust and natural sources.

Heavy Metal Characteristics and Comprehensive Quality Index Evaluation of Soil-Crop System in 11 Cities of Yunnan Province, China

Yunnan province in China is a high background area of soil heavy metals, and agricultural planting and industrial and mining activities are relatively frequent, which aggravate soil heavy metal pollution. However, at present, there are few reports on the overall or large-scale soil-crop pollution and risk assessment of heavy metals in Yunnan Province. This study through 11 cities in Yunnan province of China farmland soil-crop systems of heavy metal lead, cadmium content, enrichment coefficient is analyzed, and using the method of potential ecological harm index, index of compressive quality to evaluate heavy metal pollution soil-crop system risk. Results showed that the average content of soil heavy metal Cd and Pb were 1.31 mg/kg, 64.17 mg/kg, which are higher than the background value of Yunnan province. The average contents of Pb and Cd in the edible parts of crops were 0.20 mg/kg, 0.08 mg/kg. The average content of heavy metals in crops in Diqing (Pb) and Nujiang (Cd) was 0.72 mg/kg and 0.148 mg/kg. The enrichment coefficients of heavy metals in edible parts of crops were the largest in Diqing (Pb) and Zhaotong (Cd). The average value of ecological risk index of Pb element in soil is 2.79, which indicates that the study area is in a slight ecological hazard, the average value of the ecological risk index of Cd in soil is 126.43. The average value of the comprehensive quality impact index (IICQ) is 4.27, which indicates that the study area is moderately polluted. In this study, the contents of heavy metals Cd and Pb in soils and crops in different administrative regions were determined, and the heavy metals Pb and Cd in soil-crop system of Yunnan province, China were evaluated, it is expected to have important scientific and theoretical significance for the safe use of cultivated land to export safe agricultural products and promote the sustainable development of agriculture in Yunnan Plateau.