Average Concentrations Of Pb Research Articles

Pollution and Health Risk Assessment of Hazardous Elements in Surface Dust along an Urbanization Gradient

The hazardous element (HE) pollution of urban surface dust is a serious environmental issue, due to its toxicity and potential hazardous effects. Surface dust samples were collected from core urban, urban, and suburban gradients in the city of Urumqi in arid northwestern China, and the concentrations of six HEs, such as arsenic (As), cadmium (Cd), nickel (Ni), lead (Pb), mercury (Hg), and chromium (Cr) were determined. The pollution load index (PLI) and the US EPA health risk assessment model were applied, to assess and compare the pollution levels and the potential health risk of HEs in the surface dust in different urbanization gradients. The results indicated that the average concentrations of Hg, Cd, and Ni in the surface dust decreased in the order of core urban > urban > suburban, whereas the average concentrations of As, Cr, and Pb decreased in the order of urban > core urban > suburban. The PLI of HEs in surface dust decreased in the order of core urban > urban > suburban. The concentrations of HEs in the core urban and urban gradients were relatively higher than those in the suburban gradient. Furthermore, the total non-carcinogenic and carcinogenic risk index of the investigated HEs in surface dust decreased in the order of urban > core urban > suburban, for both adults and children. In addition, the pollution of surface dust by HEs in all urbanization gradients was more harmful to children’s health than to adults’. Overall, the potential non-carcinogenic and carcinogenic health risk of the investigated HEs, instigated primarily via the oral ingestion of surface dust, was found to be within the acceptable range. However, urbanization has effected the accumulation of HEs in surface dust, and Cr was the main non-carcinogenic risk factor, whereas Cd was the main carcinogenic risk factor, among the analyzed HEs in surface dust in three urban gradients in the study area.

Geochemistry pollution status and ecotoxicological risk assessment of heavy metal(oid)s in soil influenced by co-landfilling of MSW and sewage sludge, Morocco

Landfilling activities are one of themajorsources of heavy metal(loid)s contamination. Thus, assessing the spatial distribution ofthese elementsand evaluatingtheirpotentialhazards to public health in the areas surrounding landfills is of utmost importance. In this paper, the synergistic effects of co-landfilling of Municipal Solid Waste (MSW) and Sewage Sludge (SS) were assessed using pollution indicators, PCA, HCA, and Montecarlo probabilistic human risk assessment. To do so, 19 soil, leachate, and sewage sludge samples were collected around the landfill and their content of heavy metal(oid)s was analyzed using Inductively Coupled Plasma (ICP-AES). The average concentrations of As, Cd, Cu, Pb, Zn, Cr, Ni, Co, and Fe were 0.98, 3.14, 36.87, 41.90, 148.43, 21.64, 32.07, 4.02, and 3143.74 mg/kg dry weight, respectively. The concentration of all metal(oid)s was higher than the geochemical background and the highest amount was observed at the first 100 m from the landfill and the sampling sites affected directly by sewage sludge. The values of pollution indexes (geo-accumulation index, enrichment factor, pollution load index, ecological risk index) showedthat soils in the vicinity of the landfill displayed moderate to high contamination level, with a strong potential ecological impact. Furthermore, multivariate statistical analysis demonstrated that anthropogenic sources related to disposal practices of MSW and SS are the main responsible behind the revealed pollution. In addition, the deterministic and probabilistic human risk assessment highlighted that the non-carcinogenic risk for children and adults still within the acceptable limits. However, carcinogenic risk was well above the threshold values (10−4) for children. The elevated pollution level reflected the dangerousness of synergistic dumping of SS and MSW, which renders the avoidance of their co-landfilling mandatory.

Trace metals in surface water of the Pechora River and its tributaries: Content, water quality and risks assessment (Arctic Ocean basin)

The article is devoted to the study of trace metals content in the Pechora River and its tributaries, which is the largest river in the Arctic Ocean basin. The study of physico-chemical properties of water showed aerobic conditions of low-mineralised water with pH values suitable for drinking water. Analysis of the content of trace metals has revealed that the main flow of Al, Mn, Co, Cu, Zn, V, As, Mg and Fe into the Pechora River comes from its tributaries. The average content of Cr, Mn, Cu, Zn, Pb, V, As, Mg and Fe in the water of the Pechora River delta was higher than for the main river channel, which indicates the transfer of a large mass of trace metals to the Barents Sea and the Arctic water ecosystem. For the studied river and tributaries, chronic pollution of the Pechora River with Al, Mn, Ba, Fe, Cu, U and Pb metals has adverse effects on waterborne organisms. The degree of contamination of natural waters by metals has been assessed using water quality indices (TMPI, TMEI, TMTI) and public health risks (HI and CR). Low contamination and weak toxicity of the Pechora River water has been determined, but serious contamination, toxicity and high non-carcinogenic risk of some of its tributaries have been observed. A high carcinogenic risk has been established for the consumption of all water sampled. Al, Ni, As, Fe, Mn, Cr, Cd, and Ba were found to be the highest priority contaminating trace metals. At present, contamination of the Pechora River and its tributaries with trace metals is formed under the influence of dissolution processes of rocks of the Ural Mountains, the Taminsky Ridge, underlying mineral deposits, permafrost degradation processes and glacier melting. Anthropogenic factors include oil and gas production and transportation.

Integrated Analysis on Source-exposure Risk of Heavy Metals in Farmland Soil Based on PMF Model: A Case Study in the E-waste Dismantling Area in Zhejiang Province

In order to explore the characteristics and sources of heavy metals in farmland soil and their risks to human health and to provide an important scientific basis for farmland pollution control, 133 surface soils (0-20 cm) were collected from typical agricultural production areas in Zhejiang Province, and the contents of soil Cd, Pb, Cr, Cu, Zn, Ni, As, and Hg were determined. Various methods were applied to evaluate the degree of heavy metal pollution in farmland and its ecological risks in the study area. The method of combining Kriging interpolation and positive definite matrix factor analysis (PMF) was applied to analyze the pollution sources and quantify the contribution of each pollution source. Combined with the health risk assessment model, the risk to human health of each pollution source was evaluated from the perspective of source exposure. The results showed that the average ω(Cd), ω(Pb), ω(Cr), ω(Cu), ω(Zn), ω(Ni), ω(As), and ω(Hg) were 0.76, 65.22, 92.02, 103.92, 198.49, 36.65, 5.97, and 0.20 mg·kg-1, respectively. The average contents of Cd and Cu were higher than the risk screening values of soil contamination of agricultural land, and 85.71% and 96.24% of soil was contaminated by heavy metals. The average contents of Pb, Cr, Zn, and Ni exceeded the soil background values of the Wenhuang Plain in Zhejiang Province, and the As and Hg contents were within the limit values. The potential soil ecological risks were mainly light-moderate, accounting for 90.98%, and both high and higher risk accounted for 4.51%; Cd was the main potential ecological risk element. The main sources of heavy metal pollution in the study area were the sources of the electronic waste dismantling process (26.82%), the mixed sources of coal combustion and traffic emissions (34.50%), mixed sources of natural parent materials and agricultural inputs (25.59%), and e-waste pickling runoff and solid waste leaching sources (13.09%). The health risk of heavy metal exposure to children was significantly greater than that in adults. Mixed sources of natural parent materials and agricultural inputs contributed the most to human health risks, and Cr was the element with the greatest contribution to human health risks.

Spatial Distribution of Lead in the Soil of Urban Areas Under Different Land-Use Types

Awareness of lead (Pb) distribution and zoning in urban, agricultural, and industrial areas is of particular importance in environmental protection planning. This cross-sectional study aimed to determine the distribution of Pb in different uses with different levels of industrial development and human activities in urban areas in Hamadan during 2018. For this purpose, 146 soil samples were collected from 0-20 cm depth and prepared for air-dried laboratory analyses. Then, pH, electrical conductivity (EC), total Pb, and adsorbable Pb in the soil were measured. The results demonstrated that the mean concentration of total Pb is 88 mg/kg. In addition, the mean concentration of Pb in urban, industrial, and agricultural areas was 41 mg/kg, 30 mg/kg, and 17 mg/kg, respectively. Further, the average concentration of adsorbable Pb with a standard deviation of 0.3 in industrial, urban, and agricultural areas was 0.38 mg/kg, 0.16 mg/kg, and 0.06 mg/kg. Land use was an important source of Pb change in the studied soils; however, Pb change did not depend only on land use. Factors such as weather conditions or proximity to roads, as well as previous land uses, could affect the role of existing land use and be effective in the distribution of soil Pb. Studies revealed that the amount of the soil’s adsorbable Pb is more important than that of total Pb in different uses, which should be considered in any soil-related research.

Heavy Metals in the Water of a Developing Town of Dhubri District of Assam, India

As water is the most essential compound for living organism. Excess heavy metal causes health problems though some of them are essential in trace amounts. In this work, water samples were collected from 10 different locations of rapid developing Bilasiparatown. The water samples are then analyzed with standard methods for the determination of heavy metals namely As, Cr, Fe, Ni, and Pb. Arsenic concentrations of all the sample were within the WHO permissible limit (10µg/L). The average concentration of Cr, Fe, Ni, and Pb was found higher than the prescribed limit of WHO in most of the sources. The town is industrially underdeveloped, chemical contamination from industrial sources is insignificant, yet the water cannot be categorized as pollution free. Contaminated water is generally responsible for the spread, recurrence, and fatal consequences of various diseases.

Evaluation and Source Analysis of Soil Heavy Metal Pollution in a Planting Area in Wanquan District, Zhangjiakou City

Taking the soil of a vegetable planting area in Wanquan District of Zhangjiakou City as the research object, 132 surface and 80 deep soil samples were collected to test and analyze the contents of eight heavy metals such as As, Cd, Cr, Hg, Cu, Ni, Pb, and Zn and the occurrence forms of Cr and Ni. By applying geostatistical analysis and the PMF receptor model and combining three heavy metal pollution evaluation methods, the spatial distribution characteristics of soil heavy metals in the study area, the degree of heavy metal pollution, and the distribution of Cr and Ni fugitive forms in the vertical layer were clarified, and the sources and contribution rates of soil heavy metal pollution were analyzed. The results showed that the average contents of Cd and Pb in surface soils were higher than the background values of soils in Hebei Province, and the spatial distribution characteristics of Cr, Ni, Cu, Cd, Pb, and Zn in surface soils were similar. The ground accumulation index method showed that the study area was mainly free of pollution, with a small number of lightly polluted sites, and most of them were polluted with Cd. The enrichment factor method showed that the study area was mainly free-weakly polluted, with medium pollution of all elements; the significantly polluted elements in the background area were As, Pb, and Hg, and the significantly polluted element in the key area was Cd. The potential ecological risk index method showed that the study area was mainly lightly polluted, with local distribution. The potential ecological risk index method showed that the study area was mainly lightly polluted, with a local distribution of "medium" and "strong" risk points, with "very strong" risk points for Hg in the background area and "very strong" risk points for Cd in the focus area. These three evaluation results indicated that the background area was dominated by Cd and Hg pollution, whereas the focus area was dominated by Cd pollution. The study on the fugitive morphology of vertical soil showed that Cr was dominated by the residue state (F4) and supplemented by the oxidizable state (F3), and the vertical direction was dominated by the surface aggregation type and supplemented by the weak migration type. Ni was dominated by the residue state (F4) and supplemented by the reducible state (F2), and the vertical direction was dominated by the strong migration type and supplemented by the weak migration type. The sources of heavy metals in the surface soil were divided into three categories; Cr, Cu, and Ni were mainly from natural geological background sources. The contributions of Cr, Cu, and Ni were 66.9%, 66.9%, and 76.1%, respectively. As, Cd, Pb, and Zn were mainly from anthropogenic sources, with contributions of 77.38%, 59.2%, 83.5%, and 59.5%, respectively. Hg was mainly from dry and wet atmospheric deposition, with a contribution of 87.8%.

Seasonal Variation Characteristics and Pollution Assessment of Heavy Metals in Water and Sediment of Taipu River

Taipu River is a river spanning two provinces and one city in a demonstration area in the Yangtze River Delta on an ecologically friendly developmentand an important water source in the upper reaches of the Huangpu River in Shanghai. To understand the multi-media distribution characteristics, pollution status, and ecological risk of heavy metals in the Taipu River, the contents of heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, and Zn) in the sediments of Taipu River were analyzed, and the pollution status and potential ecological risk were evaluated using the Nemerow comprehensive pollution index, geo-accumulation index, and potential ecological risk index methods. In addition, the health risk assessment model was used to assess the health risk of heavy metals in surface water of Taipu River. The results showed that the concentrations of Cd, Cr, Mn, and Ni in the surface water of Taipu River exceeded the class Ⅲ water limit at the upstream point in spring; the concentrations of Sb exceeded the class Ⅲ water limit at all points in winter; the average value of As exceeded the class Ⅲ water limit in overlying water during the wet season; and the average values of As and Cd exceeded the class Ⅲ water limit in pore water during the wet season. The health risk assessment of surface water implied that both adults and children had higher health risk in spring and lower health risk in other seasons. The health risk of children was significantly higher than that of adults, and it mainly came from chemical carcinogenic heavy metal elements As, Cd, and Cr. The average contents of Co, Mn, Sb, and Zn in Taipu River sediments in the four seasons all exceeded the Shanghai soil baseline; the average contents of As, Cr, and Cu in summer, autumn, and winter exceeded the Shanghai soil baseline; and the average contents of Cd, Ni, and Pb in summer and winter exceeded the Shanghai soil baseline. The evaluation results of the Nemerow comprehensive pollution index and geo-accumulation index showed that the pollution degree of the middle reaches of Taipu River was higher than that of the upper and lower reaches, and the Sb pollution was more serious. The potential ecological risk index method revealed that the Taipu River sediment was at a low risk. Cd had a high contribution in both the wet and dry seasons and could be regarded as the main heavy metal of potential ecological risk in the Taipu River sediment.

Detection of Heavy Metals and Antibiotic Residues in Poultry Feeds in Selected Areas of Bangladesh

Presence of heavy metals and antibiotics in the poultry feed even in low concentrations is considered as potentially toxic and may cause hazardous effects on animal leading to accumulate in food chain. This study was performed to assess the status of heavy metals and antibiotics residue in different poultry feed samples collected from local markets of Mymensingh and Kishoreganj sadar upazila of Bangladesh. A total of 40 poultry feed samples were analyzed to detect the concentration of three heavy metals- chromium (Cr), cadmium (Cd) and lead (Pb) using atomic absorption spectrophotometry and antibiotic residues using thin layer chromatography. A survey was also conducted among 30 feed sellers in the study areas whose knowledge regarding presence of heavy metals and antibiotics residues in poultry feed was evaluated. Survey data showed that about 80% feed sellers were literate whereas 20% were illiterate. Around 23% feed sellers had knowledge about the presence of heavy metals and 90% had about antibiotic residues in poultry feeds and its detrimental public health effects. The average Cr, Cd and Pb contents in poultry feed collected from Mymensingh sadar upazila were 0.402, 1.630 and 18.314 mgkg-1, respectively. The average content of Cr and Cd in feed collected from Kishoreganj sadar upazila were 7.884 and 0.006 mgkg-1, respectively, whereas Pb content was below the detection level in this area. The results from this study showed that Cd and Pb in Mymensingh sadar upazila, Cr in Kishoreganj sadar upazila, ciprofloxacin, doxycycline and oxytetracycline in both upazilas were present at alarming levels in most of the feed samples which could be harmful for poultry as well as human health. Therefore, it is suggested to take proper steps for monitoring and regular detection of heavy metals and antibiotic residues in poultry feeds with sources identification as we as community-based awareness among the stakeholder.

Risk Profiling of Exposures to Potentially Toxic Metals PTM(S) Through Noodles Consumption. A Case Study of Human Health Risk Assessment

Abstract This study aimed to quantify levels of the toxic heavy metals metalloid arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) in commercially available noodles. Analysis was performed via the acid microwave digestion method followed by inductively coupled plasma mass spectrometry (ICP-MS). Furthermore, the potential health risks resulting from the consumption of noodles by polish consumers were evaluated using the estimated average daily intake of heavy metals (ADIHMs; µg·kg−1 bw·day−1). Additionally, to assess the potential health consequences due to noodle consumption, the total hazard quotient (THQ) and cancer risk (CR) were calculated. The average contents of Pb, As, Cd, and Hg in instant noodle samples were determined as 9.241, 8.483, 29.39, and 1.661 µg·kg−1, respectively. THQ values for heavy metal toxicity were found to be below 1, indicating that the consumer is not exposed to carcinogenic health risks associated with the analyzed metals. Additionally, the rank order of max THQ was Pb < Cd < As < Hg, and the mean THQ was Pb < Hg < As < Cd, while both the max and mean CR rank orders were Pb < Cd < As.

MONITORING OF LEAD CONTENT IN AGROECOSYSTEMS OF CENTRAL BLACK EARTH REGION OF RUSSIA

Studies on the environmental assessment of Pb content in agroecosystems were carried out in the forest-steppe zone of the Belgorod region, which is located in the south-west of the Central Black Earth region. The soil cover was represented mainly by leached chernozems. As a result of studies, it was established that in the layer of 0–20 cm of arable soils, the average gross content of Pb is 13.1, the concentration of mobile forms is 1.09 mg/kg, which does not exceed the background values and is significantly lower than the levels of APC and MAC. There were no significant differences in the content of Pb in the soil layers of 0–20 and 21–40 centimeters. The excess of background concentrations of this element is established in the soils of roadside ecosystems. The main source of Pb supply to the agroecosystems of the Belgorod region is organic fertilizers, but this does not pose a danger to soil pollution and crop production. The average Pb content of corn, barley and winter wheat grains did not differ significantly and was 0.267, 0.275, 0.292 mg/kg, respectively. Of the studied cultures, the minimum amount of this element was contained in soybean grains (0.155 mg/kg), and the maximum amount in sunflower seeds (0.335 mg/kg). Of perennial legumes, the minimum amount of Pb was contained in clover hay (0.185 mg/kg), and the maximum amount was esparceta (0.344 mg/kg). Exceeding the levels of the maximum permissible concentration and the maximum permissible level of Pb in crop production was not detected.

The Effect of Geomembrane Plastic Usage on Microplastic and Heavy Metal Contamination in Salt Field

Seawater is used to produce salt. For 10–15 years, geomembrane plastic has been used in salt fields in Indonesia to prevent contamination and increase quality and productivity. However, it is unfortunate that currently, seawater has been polluted by plastic waste, which has degraded gradually into small pieces about <5 mm in size called microplastics. In addition to microplastics, seawater is also polluted by heavy metals. Previous research indicated that the north coast of Central Java has been polluted by heavy metals whose content exceeded the threshold. The aim of this study was to analyze the amount of microplastic (MPs) and heavy metal contamination in salt. A microscope was used to measure the amount of MPs and AAS was used to measure the concentration of heavy metals. Variables that were conducted included sampling location (4 locations) and crystallization process (with and without using geomembrane). The results showed that the amount of MPs salt with a geomembrane was higher than without a geomembrane, at 337 and 326 particles/kg, respectively. The average is 332 particles/kg. Salts that use geomembranes have more contamination than salts without geomembranes. Heavy metal contamination of Pb, Cd, Hg, As, all of which were still within the threshold. The average Pb and Cd concentration in salts with and without geomembranes were 4.11 mg/kg and 4.14 mg/kg; 0.65 and 1.05, respectively. Meanwhile, the average of Hg and As concentrations for both were below than 0.001 and 0.005 mg/kg, respectively.

Heavy metals in the bottom sediments of the Sasyk estuary

Purpose. The main aim of research is to study the bottom sediments of the Sasyk estuary, in particular, to establish their lithological characteristics and the peculiarities of the distribution of heavy metals in their layers. Method. The research was done with the results of the expedition work carried out in 2018-2019, 31 samples of the bottom sediments of the Sasyk estuary, channels and paleochannels of the Kogylnyk and Sarata rivers, and rocks of the shoreline of the studied reservoir were selected. We carried out sampling along the network of 31 stations from a motor boat using a bottom-grab and orientation by GPS navigation. The content of heavy metals was determined using geochemical spectral emission analysis. Statistical and cartographic processing of the research results was carried out using geographic information systems Mapinfo, QGIS, Global Mapper and Surfer. Also, to establish the possible routes of metal migration, we used the analysis of mesotopolineaments formed according to the NASA SRTM digital terrain model, with the construction of rose diagrams of the main directions of the lineaments. The results. We established that the bottom sediments were represented mainly by grey-black, black, viscous silt, often with an admixture of shell detritus. Less often, they were composed of sand, sometimes muddy with abundant fauna. We also determined the content of heavy metals in the system of bottom sediments, features of their distribution and possible ways of infusing. Thus, in the territory of the Sasyk estuary, heavy metals of the first (Pb), second (Ni, Cu, Cr, Mo) and third (V, Mn, Ba) hazard class are found in high concentrations. The average content of Pb for the bottom sediment system of the estuary is: for sand – 32 mg/kg, for silt – 41 mg/kg. The maximum content for both is 100 mg/kg. The average Ni content is: for sand – 27 mg/kg, for silt – 62 mg/kg. The maximum content for sand is 80 mg/kg, for silt – 100 mg/kg. The average Cu content in the silt of the Sasyk estuary is 81 mg/kg, and 26 mg/kg in the sand. An elevated content of Mn, Ba and Mo was also found in several samples. Оften areas with increased concentrations of metals have a point character. In almost all cases, they are connected to the river systems adjacent to the pond. The distribution of some metals is correlated with the main directions of estuary water circulation. Wastewater is a likely sources of metals entering the estuary geoecosystem. We also assume that the migration of these elements to the pond may occur through tectonic blocks. Scientific novelty. For the first time in recent years, we have carried out expeditionary work on research of the bottom sediments of the Sasyk estuary, along the complete network of the station. We obtained the data on the gross content of heavy metals, and determined their average, maximum and minimum concentrations. For the first time, maps of the spatial distribution of metals were constructed, which made it possible to establish the main regularities of their accumulation in the bottom sediment system of the pond. Practical significance. Pollution of the bottom sediments of the Sasyk estuary with heavy metals is one of the components of today's critical ecological state of the pond, which affects the well-being of the residents of the surrounding areas. The obtained results can be used at the state level to create effective programs for quality management of the resource potential of the estuary.

Assessment of heavy metal pollution and preschool children health risk in urban street dusts from different functional areas in a typical industrial and mining city, NW China.

To assess the pollution characteristics and health risks associated with street dust exposure among preschool children in typical industrial and mining areas, we analyzed heavy metal concentrations of 20 urban street dusts in commercial area (CA), residential area (RA), scientific and educational area (SEA) and industrial and mining area (IMA) from Baiyin, NW China. The average concentrations of Cr, Mn, Ni, Cu, Zn, Cd, Pb, As and Hg were 614.96, 484.25, 1757.74, 6868.86, 893.19, 77.62, 1473.99, 15.01 and 0.59mg·kg-1, respectively. The ecological risk indexes for Cd, Cu and Hg were found as 20,075.20, 1425.07 and 1174.86, respectively, and the ecological risk was extremely high. The pollution load indexes (PLI) were > 1 for all four functional areas. The total hazard index (THI) for different functional areas were more than 1, and the main exposure pathway for children was ingestion route. Heavy metals in street dust of the IMA had the highest THI for children (43.88), and HI of Pb was being most significant (17.38). In addition, the carcinogenic risk to children via the respiratory route was acceptable. Furthermore, factor analysis and cluster analysis classified heavy metals into two groups, indicating common anthropogenic sources for Cr, Ni, Cu, Zn, Cd, Pb, As and Hg. In conclusion, urban street dusts from industrial and mining area of Baiyin, NW China were found polluted by heavy metals and the pollution would pose an obvious non-carcinogenic risk to preschool children.

Assessment of the Levels of Potentially Toxic Elements Contained in Natural Bentonites Collected from Quarries in Turkey.

Potentially toxic elements (PTEs) are an important type of pollutant, causing constant and far-reaching concerns around the world due to their increase in the mining process. Bentonite formed by the alteration of glass-rich volcanic rocks is a smectite clay consisting mostly of montmorillonite. Bentonite is an important mineral used in a wide range of applications in many fields such as oil and gas, agriculture, food, pharmacological, cosmetic, and construction industries due to its unique qualities. Given the widespread distribution of bentonite in nature and its use in a wide variety of consumer products, it is inevitable that the general population will be exposed to PTEs contained in bentonites. In this study, concentrations of PTEs in 69 bentonite samples collected from quarries located in different geographical regions of Turkey were analyzed by an energy-dispersive X-ray fluorescence spectrometric method. The average concentrations of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Zr, and Pb in bentonite samples were found to be 3510, 95, 129, 741, 30,569, 67, 168, 25, 62, 9, 173, and 28 mg/kg dry weight, respectively. Results of the enrichment factor relating to Earth's crust average indicated moderate enrichment with Cr, Ni, and Pb and significant enrichment with Co and As.

Monte Carlo-based probabilistic risk assessment for cement workers exposed to heavy metals in cement dust.

This study assessed the carcinogenic and non-carcinogenic health risks of cement plant workers exposed to chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) in cement dust using a probabilistic approach. Air samples were collected according to NIOSH 7900 and OSHA ID-121 methods and analyzed by an graphite furnace atomic absorption spectrometer. The EPA inhalation risk assessment model and Monte Carlo simulation were utilized to assess the health risks. Sensitivity analysis was used to determine the influencing parameters on health risk. The average concentrations of As and Pb exceeded the occupational exposure limit (OEL), reaching a maximum of 3.4 and 1.7 times the OEL, respectively, in the cement mill. Individual metals' cancer risk exceeded the 1E-4 threshold in ascending order of Cd < As < Cr. The mean cancer risk of Cr ranged from 835E-4 (in raw mill) to 2870E-4 (in pre-heater and kiln). Except for Cd, the non-cancer risk of metals exceeded the standard (hazard index, HQ = 1) in the ascending order of Pb < As < Cr. The mean HQ of Cr ranged from 162.13 (in raw mill) to 558.73 (in pre-heater and kiln). After adjusting for control factors, the cancer and non-cancer risks remained over the respective recommended levels. Sensitivity analysis revealed that the concentration of Cr was the most influential parameter on both carcinogenic (78.5%) and non-carcinogenic (88.06%) risks. To protect the health of cement factory employees, it is recommended to minimize cement dust emissions, implement job rotation, and use raw materials with low levels of heavy metals.

Pollution assessment of mercury and other potentially toxic elements in the marine sediments of Mambulao Bay, Jose Panganiban, Camarines Norte, Philippines

In Jose Panganiban, Camarines Norte, small-scale gold miners dispose of untreated tailings into nearby rivers, which eventually flow into Mambulao Bay. In this study, nine (9) marine sediments were collected and analyzed to assess the pollution of potentially toxic elements (PTEs) in Mambulao Bay. Au concentrations in the sediments were also determined. The results showed that the Mambulao Bay sediments have high concentrations of Hg and other PTEs. The average concentrations of potentially toxic elements in the marine sediments were observed in the following order: Zn (638 mg/kg) > Pb (297 mg/kg) > Cr (283 mg/kg) > Cu (209 mg/kg) > Ni (146 mg/kg) > As (35 mg/kg) > Hg (4.4 mg/kg) > Cd (1.4 mg/kg). Geoaccumulation index values suggest that Mambulao Bay sediments close to the Danao River estuary are strongly to extremely polluted by Hg, strongly polluted by Pb, moderately to strongly polluted by Zn, and moderately polluted by Cd, Cu, Cr, Ni, and As. A high average Au concentration (0.42 mg/kg) was also reported in the sediments. The enrichment values suggest that the PTE pollution has an anthropogenic origin, most likely from the artisanal gold mine tailings of Jose Panganiban. Most of the marine sediments have Hg, Pb, Zn, and Cu concentrations above the probable effect levels for PTEs, which can result in occasional adverse biological effects on the aquatic biota of Mambulao Bay. The average Hg content of Mambulao Bay sediments is higher than those of Honda and Agusan Bays, while the average Pb and Zn contents are higher than those of Honda and Butuan Bays, Boac River estuary, and Tañon Strait. These results can help the government address marine pollution in Mambulao Bay for sustainable aquatic resources and coastal management and can serve as a baseline for future monitoring and assessment of the water body.

Spatial Distribution and Risk Assessment of Heavy Metal(oid)s Contamination in Topsoil around a Lead and Zinc Smelter in Henan Province, Central China.

A total of 137 farmland soil samples were collected around a lead/zinc smelter within 64 km2. The concentration, spatial distribution, and potential source of nine heavy metal(oid)s (As, Cd, Co, Cr, Cu, Ni, Pb, V, and Zn) in soils and their potential ecological risk were investigated in detail. The results showed that the average concentrations of Cd, Pb, Cr and Zn in these soils were higher than their background value in Henan Province, and the average content of Cd was 2.83 times of the risk screening values in the national standard of China (GB 15618-2018). According to the distribution of different heavy metal(oid)s in soils, Cd and Pb in soil decrease gradually with the increase of distance from the smelter to the surrounding area. This indicates that the Pb and Cd originate from smelters via airborne practices according to the typical air pollution diffusion model. The distribution of Zn, Cu, and As were similar to Cd and Pb. However, Ni, V, Cr, and Co were mainly affected by soil parent materials. The potential ecological risk of Cd was higher than those of other elements, and the risk grade of the other eight elements was mainly low. The polluted soils with significantly high and high potential ecological risk covered 93.84% of all the studied regions. This should be of serious concern to government. The results of a principal component analysis (PCA) and cluster analysis (CA) show that Pb, Cd, Zn, Cu, and As were the elements mainly stemmed from smelter and other types of plants, with a contribution rate of 60.08%, while Co, Cr, Ni, and V are mainly caused by nature, with a contribution rate of 26.26%.

Niche separation, dynamics, and transport pattern of trace elements along Antarctic krill (Euphausia superba) to its exclusive predator, mackerel icefish (Champsocephalus gunnari)

In this study, the dynamics of the trophic niches and the accumulation and transfer of four trace elements—Cu, Cd, Zn, and Pb—from Antarctic krill (Euphausia superba) to mackerel icefish (Champsocephalus gunnari) were investigated. The results demonstrated that the average concentrations of Zn, Cu, Cd, and Pb in E. superba were significantly higher than those of the corresponding elements in C. gunnari. These trace elements have a biodilution effect through E. superba to C. gunnari, and Cu has the lowest biomagnification factor among those four trace elements. It is observed that the Cu concentration in E. superba is correlated with its δ15N and δ13C, and the enrichment of Pb in C. gunnari is affected by its δ15N.

Heavy Metals Assessment in Sediments Beds of Habbaniyah Lake, Iraq

Heavy Metals (HMs) concentrations in a sediment sample from Habbaniyah Lake (HL), Iraq (Cr, Cd, Ni, Fe, Co, Zn, Pb, and Cu). 33 locations have been selected in the field of study from October 2020 to April 2021 to evaluate the contamination of HMs in sediments by using pollution load index (PLI), contamination factor (CF), Contamination degree (CD), and geo-accumulation index (I-geo). Atomic Absorption Spectrometer AAS was used to determine heavy metal concentrations (USA Phoenix-986). The following are the average concentrations: 2152.97 mg/kg for Fe, 47.35 mg/kg for Pb, 25.18 mg/kg for Cr, 18.00 mg/kg for Ni, 10.60 mg/kg for Co, 9.57 mg/kg for Zn, 4.53 mg/kg for Cu and 3.53 mg/kg for Cd during the research time. The average concentration of Pb, Ni, Fe, and Cd surpassed the USEPA recommendation. Cd is responsible for extremely high contamination; Pb is responsible for moderate pollution and severe contamination at some places based on the contamination factor (CF). According to contamination degree (CD), The Lake is classified as significant pollution degree and very pollution degree in some sites. Results indicated that HL is not contaminated with HMs according to geo-accumulation index and PLI for all sample locations during the study period. The lake is unpolluted by Fe, Cr, Co, Ni, Zn, and Cu according to contamination factor (CF), geo-accumulation index (I-geo), pollution load index (PLI), and Contamination degree (CD).