Concentrations Of Other Heavy Metals Research Articles

Source-specific ecological risk analysis and critical source identification of heavy metal(loid)s in the soil of typical abandoned coal mining area

Long-term coal mining activities in abandoned coal mining areas have resulted in the migration of large quantities of heavy metals into the surrounding soil environment, posing a threat to the regional ecological environment. This study focuses on the surface soil collected from a typical abandoned coal mining area. Methods such as the pollution index (PI) and potential ecological risk index (RI) were used to comprehensively evaluate the pollution levels and ecological risks of soil heavy metals. Geostatistical analysis and the APCS-MLR model were used to quantify the sources of soil heavy metals, and Nemerow integrated ecological risk (NIRI) model was coupled to apportion the ecological risks from different pollution sources. The results indicate that the average concentrations of Cd, As, and Zn are 4.58, 2.44, and 1.67 times the soil background values, respectively, while the concentrations of other heavy metals are below the soil background values. The soil of study area is strongly polluted by heavy metals, with the pollution level and ecological risk of Cd being significantly higher than those of other heavy metals. The NIRI calculation results show that the overall comprehensive ecological risk level is considerable, with sample points classified as relatively considerable, moderate, and low at 60.53 %, 36.84 %, and 2.63 %, respectively. The sources of soil heavy metals can be categorized into four types: traffic activities, natural sources, coal gangue accumulation, and a combined source of coal mining and agricultural activities, with contribution rates of 35.3 %, 36.1 %, 19.5 %, and 9.1 %, respectively. The specific source ecological risk assessment results indicate that coal gangue accumulation contributes the most to ecological risk (36.4 %) and should be prioritized for pollution control, with Cd being the priority control element for ecological risk. The findings provide theoretical support for the refined management of soil heavy metal pollution in abandoned coal mining areas.

Source-specific ecological risk analysis and critical source identification of heavy metal(loid)s in the soil of typical abandoned coal mining area

Long-term coal mining activities in abandoned coal mining areas have resulted in the migration of large quantities of heavy metals into the surrounding soil environment, posing a threat to the regional ecological environment. This study focuses on the surface soil collected from a typical abandoned coal mining area. Methods such as the pollution index (PI) and potential ecological risk index (RI) were used to comprehensively evaluate the pollution levels and ecological risks of soil heavy metals. Geostatistical analysis and the APCS-MLR model were used to quantify the sources of soil heavy metals, and Nemerow integrated ecological risk (NIRI) model was coupled to apportion the ecological risks from different pollution sources. The results indicate that the average concentrations of Cd, As, and Zn are 4.58, 2.44, and 1.67 times the soil background values, respectively, while the concentrations of other heavy metals are below the soil background values. The soil of study area is strongly polluted by heavy metals, with the pollution level and ecological risk of Cd being significantly higher than those of other heavy metals. The NIRI calculation results show that the overall comprehensive ecological risk level is considerable, with sample points classified as relatively considerable, moderate, and low at 60.53 %, 36.84 %, and 2.63 %, respectively. The sources of soil heavy metals can be categorized into four types: traffic activities, natural sources, coal gangue accumulation, and a combined source of coal mining and agricultural activities, with contribution rates of 35.3 %, 36.1 %, 19.5 %, and 9.1 %, respectively. The specific source ecological risk assessment results indicate that coal gangue accumulation contributes the most to ecological risk (36.4 %) and should be prioritized for pollution control, with Cd being the priority control element for ecological risk. The findings provide theoretical support for the refined management of soil heavy metal pollution in abandoned coal mining areas.

The incidence of upper respiratory infections in children is related to the concentration of vanadium in indoor dust aggregates.

It has been reported that the disease-initiated and disease-mediated effects of aerosol pollutants can be related to concentration, site of deposition, duration of exposure, as well as the specific chemical composition of pollutants. To investigate the microelemental composition of dust aggregates in primary schools of Vilnius and determine trace elements related to acute upper respiratory infections among 6-to 11-year-old children. Microelemental analysis of aerosol pollution was performed using dust samples collected in the classrooms of 11 primary schools in Vilnius from 2016 to 2020. Sites included areas of its natural accumulation behind the radiator heaters and from the surface of high cupboards. The concentrations of heavy metals (Pb, W, Sb, Sn, Zr, Zn, Cu, Ni, Mn, Cr, V, and As) in dust samples were analyzed using a SPECTRO XEPOS spectrometer. The annual incidence rates of respiratory diseases in children of each school were calculated based on data from medical records. The mean annual incidence of physician-diagnosed acute upper respiratory infections (J00-J06 according to ICD-10A) among younger school-age children was between 25.1 and 71.3% per school. A significant correlation was found between vanadium concentration and the number of episodes of acute upper respiratory infections during each study year from 2016 to 2020. The lowest was r = 0.67 (p = 0.024), and the highest was r = 0.82 (p = 0.002). The concentration of vanadium in the samples of dust aggregates varied from 12.7 to 52.1 parts per million (ppm). No significant correlations between the other trace elements and the incidence of upper respiratory infections were found, which could be caused by a small number of study schools and relatively low concentrations of other heavy metals found in the samples of indoor dust aggregates. A significant and replicable correlation was found between the concentration of vanadium in the samples of natural dust aggregates collected in primary schools and the incidence of acute upper respiratory infections in children. Monitoring the concentration of heavy metals in the indoor environment can be an important instrument for the prevention and control of respiratory morbidity in children.

The Source Apportionment of Heavy Metals in Surface Dust in the Main District Bus Stops of Tianshui City Based on the Positive Matrix Factorization Model and Geo-Statistics

For the pollution assessment and quantitative source apportionment of heavy metals in surface dust, a total of 52 surface dust samples were collected from bus stops in Tianshui City. The geoaccumulation index (Igeo) and potential ecological risk index (RI) were used to analyze the pollution levels caused by heavy metals. The Positive Matrix Factorization (PMF) of the receptor modeling and geo-statistics were employed to analyze the source of the heavy metals. The results were as follows. ① Except for Mn, Co and V, the mean concentrations of other heavy metals have exceeded the local background value of Gansu. The percentage of excessive concentrations of Cu, Zn, Sr, Ba and Pb in the samples was 100%, and that of Cr, Ni and As were 96.15%, 94.23%, and 96.15%, respectively. ② Semivariogram model fitting showed that the block-based coefficients of Cu, Zn, Sr, Ba, Pb, Cr, Ni, and As were between 0.25 and 0.75, indicating that they were mainly affected by human factors. The high values of Pb, Zn, Ni and As were mainly distributed in the eastern part of the study area, and the high values of Cu, Sr, Ba and Cr were distributed in a spot-like pattern in the study area. ③ The Igeo results showed that As, Cu, Zn, and Pb were the main contamination factors, and the optimized RI showed that the heavy metals were the overall ecological risk of intensity, among which Pb, As and Cu were the main ecological factors and should be taken as the priority control objects. ④ Based on the PMF, there are four main sources of eleven heavy metals. V, Mn, and Co were attributed to natural sources, accounting for 18.33%; Cu, Sr, and Ba were from mixed sources of pollution from transportation and industrial alloy manufacturing, accounting for 26.99%; Cr and Ni were from sources of construction waste pollution, accounting for 17.17%, As, Zn and Pb were mainly produced by coal-traffic mixed pollution emissions, accounting for 37.52%. Overall, the study area was dominated by coal-traffic emissions.

Stabilization of As and Heavy Metal-Contaminated Soils by Two Mine Drainage-Treated Sludges

This study explored and analyzed the potential of the practical use of acid mine drainage-treated sludge (AMDS) as a new soil stabilizer for arsenic (As) and heavy metals. Various analyses, toxicity evaluations, and extraction batch experiments were performed to investigate the characteristics of the AMDS as a soil stabilizer and to identify the main mechanisms to fix As and heavy metals on the AMDS in soil. Two types of AMDS, copper metal mine drainage-treated sludge (MMDS) and coal mine drainage-treated sludge (CMDS) and four contaminated soils with different pollution scenarios were used in the experiments. ‘Soil A’ and ‘Soil D’ were mainly contaminated with Cd, Pb and Zn. ‘Soil B’ and ‘Soil C’ were contaminated with As. Results from XRD, XRF, SEM-EDS, TG-DTA, and BET analyses suggested that AMDS is mainly composed of Fe- and Ca- bearing minerals such as CaCO3, Ca(OH)2 and amorphous Fe-oxide (hydroxide), which have a large surface area and high adsorption capacity for As and heavy metals. From batch extraction experiments, the Pb stabilization efficiency of both of the AMDSs in soil A, which has a high Pb and Zn content, was higher than 90%. The high heavy metal stabilization efficiency comes directly from the electrostatic attraction between metal cations and the negatively charged AMDS surface and/or from the co-precipitation of metal oxide (hydroxide) and CaCO3, which occurs comprehensively on the AMDS surface. In the case of Zn, the stabilization efficiency in soil A was somewhat low due to the adsorption competition with Pb, but the Zn stabilization efficiency of the CMDS in soil A was higher than 80% (70% or higher for the MMDS). For soil D, the Zn stabilization efficiency of two AMDSs was higher than 85% because of the lower concentration of other heavy metals in soil D, compared to in soil A. The As stabilization efficiency of the AMDSs in soil contaminated with As (soil B and soil C) was higher than 85%, (mostly > 95%). The overall stabilization efficiency of two AMDSs for heavy metals and As were higher than 75% and 85% (mostly > 90%), respectively, regardless of soil type. We concluded that this high As stabilization efficiency was due to the formation of a new complex by ligand exchange between the Fe- (oxide) hydroxide and the arsenate and also to the cation bridge effect between the AMDS surface and the arsenate as well as the co-precipitation.

Environmental Magnetic Characteristics and Heavy Metal Pollution Assessment of Sediments in the Le’an River, China

Environmental magnetism parameters have become a useful tool in addressing environmental issues. Due to the rapid, sensitive, economical and non-destructive characteristics of environmental magnetism, the present contribution focuses on magnetism parameters as proxy for heavy metal pollution, especially from their relationship with contents of heavy metal. We evaluated heavy metals pollution and examined environmental magnetism in the Dexing section of the Le’an River. The pollution load index (PLI) of Cr, Pb, As, Cu and Zn, as well as the concentration of other heavy metals, were analyzed, and the magnetic indexes of various sediments were analyzed. The results showed that the concentrations of all heavy metals far exceeded the local background values, and that the average contamination factor of Cu was as high as 22.88, making it the element of most serious contamination. The problem of heavy metal pollution near the mine is very serious. The content of magnetic minerals in sediments of Le’an River is relatively high and the composition of magnetic minerals is relatively stable. The stable-single domin (SSD) content is high at S1 and S10, indicating that ferromagnetic mineral content is relatively rich here, which dominates the magnetic characteristics of the sample. In general, it was found that environmental magnetism indicators did not exist in the Dexing section of the Le’an River that could clearly indicate the concentration of heavy metal pollution. Only a few heavy metals can be effectively indicated by magnetic parameters. IRM-20mT and S-ratio can be used as indicators of Cr, Pb, As, Cu and Zn, but they are not accurate. The correlation between Sr and magnetic indexes IRM200mT, IRM300mT, SIRM, IRM-300mT and HIRM is significant, which can be used as an indicator of Sr concentration. IRM20mT can also be used as an indicator of Hg concentration.

Heavy Metals and Microorganisms in Borehole Water Around the Olusosun Dumpsite in Lagos, Nigeria: Occurrence and Health Risk Assessment

Dumpsites are the most cost-effective and widely used method of waste disposal. However, studies have linked dumpsites to groundwater contamination, necessitating a safety assessment of groundwater sources near dumpsites. The safety of borehole water near the Olusosun dumpsite in Ojota, Lagos, Nigeria, was investigated in this study. Water samples were collected at distances of 100, 200, and 300 m from the dumpsite and subjected to conventional heavy metal analysis and microbiological tests. The average daily intake (ADI) and hazard quotient (HQ) of heavy metals were also estimated. The heavy metal analysis revealed that copper (Cu) and iron (Fe) levels exceeded permissible limits recommended by the World Health Organization (WHO) at the three locations, while manganese (Mn), lead (Pb), and cadmium (Cd) concentrations were within non-permissible levels only at the distances of 100 and 200 m. The concentrations of other heavy metals tested, such as zinc (Zn), nickel (Ni), and chromium (Cr), were within tolerable limits. The ADI of heavy metals at the three locations was within acceptable levels. However, the HQ of Cd in all the locations, as well as Pb at the distance of 100 m and Cr at distances of 100 and 200 m, was greater than the threshold of 1. The microbiological analysis revealed that all the water samples had non-permissible bacteria and coliform counts. The results obtained suggest that the borehole water around the dumpsite is grossly contaminated, with contamination levels increasing significantly (P≤0.05) with closeness to the dumpsite (100>200>300 m). Therefore, there is a need for heavy metal remediation and disinfection of the dumpsite.

Source Analysis of Heavy Metal Pollution Using UNMIX and PMF Models in Soils along the Shuimo River in Urumqi, China.

Eight kinds of heavy metals in soil within 0-2 km from the banks of Shuimo River in Urumqi were analyzed by using an X-ray fluorescence spectrometer and national standard detection methods. Unmix and PMF models are comprehensively used to analyze potential pollutant sources and contribution rates. Soil samples are sampled in three layers of 0-20, 20-40, and 40-60 cm, and each group of sample points in each layer is 5 m, 1 km, and 2 km away from the riverbank, respectively. Only the average concentration of Mn in each layer of soil is lower than the background value, according to the analytical results, while the average concentration of other heavy metals surpasses the background value. The highest proportion of exceeding the background value is Ni in the 40-60 cm soil layer, up to 1.92 times. Unmix and PMF models are used to analyze pollutants' source quantity and contribution rate, respectively. The results show that the two models can identify two pollution sources at the three soil layers, and their contribution rates are similar, and each index of the analysis results of the two models is within the required range of model reliability. By comparing with the Pearson correlation coefficient and distribution map of heavy metal concentration in surface soil, it is concluded that Zn, Pb, Cr, and Cu are mainly from industrial sewage and air pollution from coal combustion, while As, Mn, Ni, and V are mainly from agricultural pollution and light industrial pollution. In future research, it is necessary to investigate the change of heavy metal concentration in detail from the time dimension to further quantitatively calculate the potential pollutant source and contribution rate.

Enrichment Factors, Health Risk, and Source Identification of Heavy Metals in Agricultural Soils in Semi-arid Region of Hainan Island

To understand the enrichment factors and pollution levels of heavy metals in agricultural soils in the semi-arid region of Hainan island, 1818 surface soil samples were collected in Gancheng Town and analyzed for their heavy metal contents and physicochemical composition. Correlation analysis was used to determine the heavy metal enrichment factors. The geo-accumulation index (Igeo), comprehensive ecological risk index (RI), and hazard index (HI), as well as carcinogenic risk (CR), were used to assess the degree of pollution and health risk. Positive matrix factorization (PMF) was used to determine the primary sources of pollution and priority sources. The average values of heavy metal contents in the topsoil were 22.7, 0.128, 33.4, 14.5, 0.032, 9.32, 32.5, and 43.3 mg·kg-1 for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively. With the exception of Zn, the concentrations of other heavy metals in the topsoil were higher than the soil background values of Hainan, showing different degrees of heavy metal accumulation effect. The Igeo revealed that the major pollutant element in soils was As, followed by Cd and Cu. The RI showed that the proportion of soil samples that were high-risk level or worse was 29.4% of the total number of samples, among which As was the major source of risk. The health risk assessment results indicated that As, Cr, and Ni exposure presented carcinogenic risk for children with high CR values. Based on PMF, four major sources of heavy metals were identified in the study area. Hg was derived mainly from industrial sources, and As was closely associated with agricultural activities. Ni, Cu, Cr, and Zn were related to soil parent materials. Pb and Cd were associated with agricultural activities and traffic emissions. The PMF models combined with correlation analysis were useful for estimating the source apportionment of heavy metals in soils.

Challenges for sustainable water use in the northern part of Pakistan focusing on hydrology assessment of non-industrial zone

The current study was focused on the water quality assessment of the District Muzaffarabad (DMZD) Azad Jammu and Kashmir (AJK), the northern part of Pakistan. The qualitative assessment was done on the surface water bodies, spring waters and tap water sources of DMZD. A total of eight parameters were assessed in this exploration including physical parameters, microbiological analysis, anion detection, and heavy metal exploration. Some physical parameters i.e., Electrical Conductance and Total Dissolved Solid showed higher variance than WHO allowed limits having a positive correlation within themselves that has indirectly affected the water quality of the region. Microbiological analysis was also performed using 3M-petrifilms with a capacity to quantify and distinguish between coliforms and E. coli by producing different stains on the surface chromophore of the petrifilm. Amongst eighty collected samples, more than 90% were contaminated with bacteria i.e., coliforms or E. coli. Poor water management and open disposal of sewage, sludge and other waste products were the main causatives of bacterial pollution. The significant anions which were crossing the maximum concentration limits (MCL) were fluoride, nitrite and nitrate (2.981 mg/L, 0.418 mg/L and >30 mg/L). Amongst anions especially, nitrite and nitrate were the real culprits of many health-related issues in humans’ i.e., cancers, etc. and fluorides were responsible for diseases such as dental fluorosis, skeletal fluorosis etc. Water quality was generally poor and unsafe in the studied areas. We have also analyzed heavy metal content in the water samples collected from DMZD, AJK. Heavy metals ions detected in the collected water samples were; Arsenic (As3+), Copper (Cu2+), Iron (Fe2+), Lead (Pb2+) and Nickel (Ni2+). We used robust Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) for heavy metal detection having broader LoD for a variety of turbid samples especially. Along with some fluctuations in the concentrations of other heavy metals, a significant spike was observed for Pb2+ (0.01818 mg/L) in ICP-OES experiments exceeding from MCL (0.01 mg/L) of lead setup by WHO. A higher concentration of Pb2+ was due to anthropogenic sources and natural sources in District Muzaffarabad. The study was aimed to find out the cause of the recent upsurge of different lethal diseases (gastrointestinal, cardiovascular, cancers etc.) in the region relative to water contamination. From this study and application of analytical methods we have revealed meaningful information about the unexplored water quality data of the studied area.

Effects of Charcoal Production on Soil Physicochemical Properties in Moro Local Government Area of Kwara State, Nigeria

Charcoal production is a major economic activity in rural Kwara State, North-Central Nigeria. Given that it generally involves the use of traditional earth kilns, this study was designed to investigate the effects of charcoal production on the physical and chemical properties of soil. Replicate soil core samples were collected within a depth of 0 - 20 cm from 19 charcoal kiln sites (CKS) and 19 adjacent control sites (ACS) across five administrative districts in the study area. These samples were subjected to laboratory analysis to determine their physical and chemical qualities and then t-test was used to statistically compare the CKS and ACS soils. There was no significant difference in soil texture between both sites. However, CKS soil pH and electrical conductivity significantly increased (p 0.05) due to charred biomass introduced to soils by the process of charcoal production. The CKS cation exchange capacity, Ca and Mg increased significantly (p < 0.0001) by 40.11%, 57.15% and 89.16%, respectively. Charcoal production significantly reduced Fe by 28.54%, while the concentration of other heavy metals remained similar between both sites. The findings showed that charcoal production using traditional earth kilns improves soil physical and chemical properties for agriculture purposes. However, further studies are suggested to understand its effects on vegetation cover and soil biota.

Research of heavy metals leaching from sediments after feritization processing of galvanic sludge

Possibility of environmental safety increasing for industrial enterprises as a result of resource-saving technology implementation for processing galvanic sludge is considered. An experimental study of stability for sediments after ferritization processing of galvanic sludge and exhausted technological solutions was carried out. As a result of dynamic leaching of heavy metal ions, the immobilization properties of sediments were determined, which were obtained at different technological parameters of the ferritization process. It is shown that the level of immobilization of heavy metals in ferritic sediments has significantly higher values in comparison with sediments of traditional wastewater neutralization. It was found, that the precipitate obtained at following key parameters of reaction mixture for the ferritization process: the total concentration of heavy metal ions 10.41 g/dm3; ratio of concentrations of iron ions to total concentration of other heavy metals ions 4/1 and pH value of 10.5, is characterized by the highest degree of immobilization of heavy metals in the sediments of 99.96% mass. Using the results of a complete factorial experiment, regression equation for the leaching of heavy metal ions (iron, nickel, copper and zinc) from ferrite sediments was obtained: ratio of iron concentrations to the total concentration of other heavy metals and the pH value of reaction mixture. The adequacy of coefficients of regression equations was evaluated according to the criteria of Student and Fisher, which with 95% reliability correspond to the experimental results of the study. The proposed calculation algorithm provides an opportunity to increase efficiency and automation of ferritization process. Subsequent use of the research results will allow to implement reliable utilization of ferritized galvanic waste by application them into the row materials for obtaining alkaline cements for special purposes.

Health Risk Assessment of Liza parsia Fish Lipids: Heavy Metals and DDTs Contaminations

Background: Fish is a source of nutrition; however, toxic substances and heavy metals may enter human body due to consuming contaminated fish. The aim of this study was to investigate the levels of heavy metals and DDTs in Liza parsia, a fish species, and assess the health risk of the contaminants in the fish samples. Methods: The extracted fish lipid was added with n-hexane and H2SO4 and was kept for long time. The upper organic part was collected for the analysis of DDTs by gas chromatography equipped with electron capture detector. The fish samples were homogenized by wet digestion method, and the heavy metal contents were analyzed, using an atomic absorption spectrophotometer. The health risks of the fish samples were assessed based on target hazard quotient and target cancer risk. Results: The pesticide contents of DDT, DDD, DDE and DDTs in the fish samples were 0.0414, 0.000253, 0.015 and 0.0567ng/g, respectively. Also, the mean concentrations of Mn, Fe, Cu and Zn were 35.42±10.05, 318.75±242.45, 41.67±4.78 and 281.25±5.42 mg/kg, respectively. Of note, the Cd and Pb contents were below the detection limits. The concentrations of other heavy metals were above the reference limits, which can cause various disease processes. Conclusion: The contents of four heavy metals and DDTs in the samples were above the limits. The main sources of these substances are likely due to human anthropogenic activities. Fish and other edible aquatic animals should be monitored regularly and the heavy metal levels be determined and declared to the public.

Evaluation of uranium and other toxic heavy metals in drinking water of Chamba district, Himachal Pradesh, India for possible health hazards

Uranium and other heavy metals are found in the natural water and may enter the human body when ingested by drinking water. Uranium being radioactive may provide radiological risks, whereas chemical toxicity of uranium and other heavy metals may pose a serious threat to human life. The current research has been undertaken for trace level analysis of uranium and other heavy metals (Fe, Zn, Cu, As, Co, Ag, Cd and Pb) in drinking water samples collected from different locations and sources of water from Chamba district of Himachal Pradesh, India. Uranium concentration has been assessed using LED fluorimeter, whereas the concentration of other heavy metals has been estimated utilizing inductively coupled plasma mass spectrometry (ICPMS). Uranium concentration in water samples have been found to vary from 0.50 to 90.46 µg L−1 with mean value of 6.51 µg L−1. About 96% samples have uranium concentration lower than the suggested safe limits of 30 µg L−1 by (WHO, Guidelines for drinking-water quality, World Health Organization, Geneva, Switzerland, 2017). The cancer mortality and morbidity risks have also been estimated using the uranium concentration in drinking water samples. The annual ingestion dose (AID) susceptible to distinct age groups due to ingestion of these waters has also been computed and is found above the prescribed dose of 100 μSv y−1 (International Commission on Radiological Protection, ICRP, (1999) Protection of the public in situations of prolonged radiation exposure. Ann ICRP 29(1–2). ICRP Publication 82) in the water sample of Behra for adolescents and adult males as well as for pregnant and lactating females. Lifetime average daily dose (LADD), Hazards Quotient (HQ) and Heavy Metals Pollution Index (HPI) due to the presence of heavy metals in drinking water samples have also been calculated. LADD for uranium, As and Fe have been found above the recommended limits in the drinking water samples of some villages. Average HQ of the study area has been observed below 1 indicate that the water is good for drinking purpose. HPI has also been found below the analytical pollution index of 100 indicate that the water of the area is not polluted.

Assessment of physico-chemical characteristics of river water emphasizing tannery industrial park: a case study of Dhaleshwari River, Bangladesh.

Pollution of industry-adjacent surface water bodies become a major environmental concern in Bangladesh recently. Therefore, this study aimed to elaborate assessment of physico-chemical characteristics of the Dhaleshwari River (the adjacent river of newly shifted tannery industrial park) and also the discharged effluent from the central effluent treatment plant (CETP) considering both seasonal and spatial variations. Among the examined 30 water quality parameters (including 11 heavy metals), only TDS, Cl-, NO3-N, EC, Cu, Zn, Cd, and Ni met the standards for discharged wastewater from industrial units into inland surface water set by Bangladesh government. This indicated that the CETP is not fully and/or effectively functioning. Out of 19 parameters (excluding heavy metal), 14 parameters exceeded the Bangladesh standard for drinking water quality either spatially or seasonally. The river water quality indicated slowly biodegradable capacity with algal bloom risk. The concentrations of the studied heavy metals in the river water followed a decreasing order of Ca > K > Mg > Na > Fe > Cr > Pb > Ni > Cu > Zn > Cd, and Cr concentration in the winter season exceeded the standard values. The concentrations of other heavy metals met the quality standard that indicated still the river is capable to self-purify. Furthermore, strong (p < 0.01) and significant (p < 0.05) correlation were observed among the quality parameters in river water. This study suggested that the efficiency of the existing CETP needs to be enhanced, and the proper operation and maintenance are required to meet the desired discharge standard quality. Also, all the unauthorized wastewater outfalls from tanneries must be closed to save the Dhaleshwari River.

Use of Two Aquatic Snail Species as Bioindicators of Heavy Metals in Tigris River-Baghdad

Thirty individuals of Bellamya bengalensis and Physella acuta were collected and identified from the Tigris River in Baghdad during the period between October to November 2017. The efficiency of bioaccumulation of the two species as bioindicators for aquatic heavy metal pollution with Cd, Ni, Pb and Cu was investigated. Both snail species had the ability to accumulate heavy metals. The mean of Ni concentration in soft tissues of both snails was 1.53 ppm while the mean concentration of other heavy metals was significantly lower; they reached 0.51 ppm, 0.36 ppm and 0.29 ppm, respectively. While no significant differences between B. bengalensis and P.acuta were noticed in the ability to accumulate the heavy metals. It is concluded that both snails shared the features of good bioindicators due to their sensitivity to pollution.:

Survey of aflatoxin B1 and heavy metal contamination in peanut and peanut soil in China during 2017–2018

Peanut, as a nutritious, healthy and delicious food, is susceptible to contamination by aflatoxin B1 (AFB1) and heavy metals, which has an adverse impact on the healthy development of peanut industry in China. This research was to evaluate the contamination of AFB1 and heavy metals (cadmium, chromium, lead, tin, copper and zinc) in peanut, to analyze the difference of AFB1 and heavy metal contamination in peanut in the four main peanut producing regions (Northeast area, Yellow River basin, Yangtze River basin and Southeast coast), and to analyze and discuss the difference of heavy metal content in peanut kernel, peanut shell and peanut soil. The results showed that the mean concentration of AFB1 in peanut was 1.08 μg/kg, and the detection rate of AFB1 was 33.80%. There was no significant difference in AFB1 contamination of peanut between 2017 and 2018. The most serious AFB1 contamination region was the Yangtze River basin, followed by the Southeast coast, the Yellow River basin and the Northeast area. The average levels of cadmium (Cd), chromium (Cr), lead (Pb), tin (Sn), copper (Cu) and zinc (Zn) in peanut kernel were 0.18, 0.44, 0.03, 0.01, 9.24 and 31.42 mg/kg, respectively. There was a significant difference in the mean content of heavy metals (Cr, Sn, Cu and Zn) in peanut kernels between 2017 and 2018. The mean content of Cd in peanut kernel was the highest in Northeast area, and there was no significant difference in the mean content of Pb in the four main peanut producing regions. The average concentration of other heavy metals (Cr, Sn, Cu and Zn) in peanut kernel in south of China (Yangtze River basin and Southeast coast) was higher than that in north of China (Northeast area and Yellow River basin). Due to the different bio-accumulation ability of peanut kernel and peanut shell to different heavy metal, the average levels of heavy metals in peanut kernel and peanut shell were different. The ability of peanut kernel to bio-accumulate Cd, Cu and Zn was stronger than that of peanut shell, and the ability of bio-accumulate of Cr, Pb and Sn was weaker than peanut shell. There was a significant positive correlation between heavy metal pollution of peanut and heavy metal content in soil. In conclusion, the situation of AFB1 and heavy metal contamination in peanut in China was not optimistic, and the pollution of peanut in south of China was more serious than that in north of China. Therefore, the control and prevention of AFB1 and heavy metal in peanut should be strengthened.

Assessment of heavy metal contamination in natural waters of Dereli, Giresun: an area containing mineral deposits in northeastern Turkey.

The concentration of heavy metals in the natural waters of the area surrounding Dereli (Giresun), a mineralized area, was determined. In addition, the physicochemical parameters (such as pH, Eh, and HCO3-) influencing the concentration of dissolved metals in waters were evaluated. Samples were collected from stream, spring, and main river waters, some of which are used by local residents for drinking, fish farming, and animal husbandry. The present data indicate that the water-rock interaction is the main process controlling the chemical composition of waters in the area. The waters are predominantly CaMgHCO3-type waters with alkaline pH values. Heavy metal concentrations (Pb, Zn, Cu, Fe, Mn, U, Cd, As, Hg, Sb, Ni, Co, and Ba) in waters were generally low. Relatively high values of certain metals were determined in waters of the Kotana and Kurtulmus sites of Dereli. The levels of Pb in the river, stream, and spring water samples in these sites were somewhat higher than the Pb values reported in the literature for natural waters. However, these values only slightly exceeded the Pb water limit values proposed by the USEPA and the WHO. In addition, the concentrations of other heavy metals, except Pb, were fairly similar to those of other natural waters and these values were also under the drinking water limits set by the WHO and the USEPA. This study shows that waters in the area of Dereli were not significantly affected by mineralization. This is most likely caused by the bicarbonate-rich waters affecting the dissolved metal concentrations.

Environmental Impact of Heavy Metals from Poultry Waste Discharged into the Olosuru Stream, Ikire, Southwestern Nigeria

Water supplies can be contaminated by anthropogenic activities. The poultry industry uses a variety of heavy metals as additives in chicken feed, but excretion, runoff and dumping of heavy metals can threaten water bodies and have adverse effects on human health. The aim of the present study was to determine the environmental impact of heavy metals from poultry waste discharged into the Olosuru stream, located in Ikire, southwest Nigeria. In order to study changes in heavy metal loads, samples were collected six times during the wet season (September, October 2014 and April 2015) and dry season (November 2014, January and February 2015). The inhabitants of Olosuru village use water for domestic and agriculture purposes from the Olosuru stream which is located only a few meters from a poultry farm discharge point. Three stations were sampled, upstream to downstream, with 500 meter distance between each point. Selected heavy metals concentrations in the Olosuru stream were all above the World Health Organization (WHO) standard for drinking water. The highest mean concentrations of heavy metals were recorded at the downstream station, while arsenic, iron and lead showed significant spatial and seasonal differences. Seasonally, the highest iron concentrations were recorded in the dry season (0.104±0.401 mg/L), while the mean concentrations of other heavy metals recorded during the sampling period were higher during the wet season. Concentrations of heavy metals in the present study were above acceptable limits. Poultry waste discharged into the Olosuru stream, can have negative impacts on the stream and health implications for local residents. The authors declare no competing financial interests.

Present restrictions of sewage sludge application in agriculture within the European Union

The use of sludge in agriculture within the European Union (EU) is currently regulated only by the limits of heavy metals (Cd, Cu, Hg, Ni, Pb and Zn) listed in Council Directive 86/278/EEC. This document is now more than 30 years old. Several European countries have introduced more stringent requirements in comparison with the directive, and have adopted limits for concentrations of other heavy metals, synthetic organic compounds and microbial contamination. The paper provides an overview of the current limits of these substances in sewage sludge and concentration limits of heavy metals in soil intended for sludge application, together with applicable laws and regulations in European Union countries. There is a need to update these regulations taking into account the current risks associated with the application of sludge to agricultural land, with the possibility of using ecotoxicological tests to assess the risks. A wide range of technologies for sewage sludge processing is used in EU countries. The predominant choice is a direct application in agriculture followed by composting. The use of sewage sludge in agriculture in 2014 and 2015 in 13 EU countries that provided data amounted to 22.6% (2014) and 22.1% (2015) of produced sludge and 23.3% (2014) and 23.1% (2015) of sludge disposed. It is also highly variable within EU countries ranging between zero (Malta, Slovenia, Slovakia) and 80% (Ireland). Over 50% of sewage sludge is used in agriculture in Bulgaria according to 2015 data.