Occurrence Of Heavy Metals Research Articles

Occurrence and transformation of heavy metals during swine waste treatment: A full scale study

This study tracked the fate of nine detected heavy metals in an industrial swine farm with integrated waste treatment, including anoxic stabilization, fixed-film anaerobic digestion, anoxic-oxic (A/O), and composting. Results show that heavy metals exhibited different transformation behaviors in the treatment streamline with Fe, Zn, Cu and Mn as the most abundant ones in raw swine waste. The overall removal of water-soluble heavy metals averaged at 30 %, 24 % and 42 % by anoxic stabilization, anaerobic digestion and A/O unit, respectively. In particular, anoxic stabilization could effectively remove Cu, Mn and Ni; while A/O unit was highly effective for Fe, Cr and Zn elimination from water-soluble states. As such, the environmental risk of liquid products for agricultural irrigation decreased gradually to the safe pollution level in swine waste treatment. Furthermore, heavy metals in the solid (slurry) phase of these bioprocesses could be immobilized with the passivation rate in the range of 42–70 %. Nevertheless, heavy metals preferably transformed from liquid to biosolids to remain their environmental risks when biosolids were used as organic fertilizer in agriculture, thereby requiring effective strategies to advance their passivation in all bioprocesses, particularly composting as the last treatment unit.

Occurrence, distribution, and ecological risk of heavy metals and persistent organic pollutants (OCPs, PCBs, and PAHs) in surface sediments of the Ashtamudi wetland, south-west coast of India

Monitoring heavy metals (HM) and persistent organic pollutants (POP) has become more important recently, as they pose serious threats to tropical aquatic ecosystems. The Ashtamudi wetland a Ramsar Site in the southwest coast of India must be monitored due to the intense urbanisation and anthropogenic activities that occur in the nearby areas of this wetland. This study aims to identify potential sources of POPs (OCPs, PCBs, and PAHs) and HM in the surface sediments of Ashtamudi wetland, as well as to assess their ecological risk. The enrichment factor (EF), contamination factor (CF), degree of contamination (CD),geo-accumulation index (Igeo), pollution load index (PLI), and sediment quality guidelines (SQG) were used as pollution indices. The average concentrations of HM were Iron (39582.52 mg/kg) > manganese (365.92 mg/kg) > Zinc (91.39 mg/kg) > nickel (49.36 mg/kg) > Copper (31.47 mg/kg) > lead (21.21 mg/kg) > Cadmium (0.73 mg/kg). The concentrations of HM detected during the study were on par with or even higher than the other coastal systems. Several areas of the Ashtamudi wetland are extremely enriched and moderately to considerably contaminated with cadmium (EF and CF indices). Nickel exceeds the ERM (Effects Range Median) in some sampling stations. The Ashtamudi wetland has not been seriously contaminated by organochlorine pesticides (2.03 to 2.45 μg/kg) and polychlorinated biphenyls (0.26 to 0.35 μg/kg). Sediments are moderately contaminated with polycyclic aromatic hydrocarbons (202.81–158.23 μg/kg) from urban emission sources of Kollam. These results can be used as a reference point for future research on organic contaminants in Indian wetlands and highlight the need for effective controls of micro pollutants.

Occurrence and dietary exposure assessment of heavy metals in baby foods in the Kingdom of Saudi Arabia.

Early childhood exposure to heavy metals like arsenic (As), cadmium (Cd), and lead (Pb) through baby foods unfolds many concerns about their toxic effects on growth and health. In this study, occurrence and dietary intake of As, Cd, and Pb in stage 1 infant formula (0-6 months), stage 2 infant formula (7-12 months), cereal-based meals, and biscuits were estimated. First, the levels of As, Cd, and Pb were determined with ICP-MS, followed by the calculation of estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) for As and Cd, and margin of exposure (MoE) for Pb. Mean levels of As, Cd, and Pb were the highest in cereal-based meals and biscuits as 15.5-11.1, 5.18-8.76, and 35.2-53.8 μg/kg, respectively. Newborns to 6 months old infants were estimated to be the highest exposed population to Cd and Pb (0.08 and 0.36 μg/kg bw/day), while infants aged 7-12 months old were exposed the highest to As. Based on the THQ, HI, and MoE findings, the current exposure levels from the selected baby foods to As, Cd, and Pb pose low potential chronic risks to both infant age groups. This research provides a roadmap for future investigations in chemical contaminants often detected in baby foods consumed regularly by Saudi infants.

Molecular Evidence for Occurrence of Heavy Metal and Antibiotic Resistance Genes Among Predominant Metal Tolerant Pseudomonas sp. and Serratia sp. Prevalent in the Teesta River.

Riverine ecosystems polluted by pharmaceutical and metal industries are potential incubators of bacteria with dual resistance to heavy metals and antibiotics. The processes of co-resistance and cross resistance that empower bacteria to negotiate these challenges, strongly endorse dangers of antibiotic resistance generated by metal stress. Therefore, investigation into the molecular evidence of heavy metal and antibiotic resistance genes was the prime focus of this study. The selected Pseudomonas and Serratia species isolates evinced by their minimum inhibitory concentration and multiple antibiotic resistance (MAR) index showed significant heavy metal tolerance and multi-antibiotic resistance capability, respectively. Consequently, isolates with higher tolerance for the most toxic metal cadmium evinced high MAR index value (0.53 for Pseudomonas sp., and 0.46 for Serratia sp.) in the present investigation. Metal tolerance genes belonging to PIB-type and resistance nodulation division family of proteins were evident in these isolates. The antibiotic resistance genes like mexB, mexF and mexY occurred in Pseudomonas isolates while sdeB genes were present in Serratia isolates. Phylogenetic incongruency and GC composition analysis of PIB-type genes suggested that some of these isolates had acquired resistance through horizontal gene transfer (HGT). Therefore, the Teesta River has become a reservoir for resistant gene exchange or movement via selective pressure exerted by metals and antibiotics. The resultant adaptive mechanisms and altered phenotypes are potential tools to track metal tolerant strains with clinically significant antibiotic resistance traits.

Heavy metal occurrence within urban agriculture practices in eastern zones of Nairobi city

Urban agriculture although growing in importance, requires farmer practices to adapt to dynamics of urbanization having implication on quality of produce and public perception. The objective of this research was to assess heavy metal occurrence in inputs and food crops for urban farms in the eastern zone of Nairobi, determine differences in element uptake by crops and to examine influence of environmental quality of the surrounding spaces. A quasi research design approach was used to identify farm plots for field survey in three locations. Samples of tomatoes (Lycopersicon esculentum), arrowroots (Colocasia esculenta), and kales (Brassica oleraceae var. Acephala), water and soil samples were collected. Concentration of cadmium, manganese, zinc and lead were analysed using Atomic Absorption/Flame Emission Spectrophotometer. One way ANOVA was used to examine mean differences of heavy metals between locations and compare transfer factor (TF) index of the crops. Elements that were above allowable limits (mg/kg) in the crops were Cd (1.7 - 4.49), Mn (62.54 - 89.15), Pb (0.161 - 0.56) and Zn (0.44 - 4.95) in arrowroots; Cd (1.76 = 5.27) and Mn (3.65 = 26.86) in kales and Cd (1.17-3.51), in tomatoes. Cadmium content was highest in farm plots within Kasarani (2.44±0.86 mg/kg) and was significantly different from other two locations (p < 0.05, Tukey HSD test). Between the neighbourhood qualities, heavy metal contents were different but not significant (p > 0.05) between classes. The mean TF index for the heavy metals decreased in the order Cd>Pb>Zn>Mn. Transfer factor index of more than 1 for cadmium was observed in arrowroots, kales and tomatoes. Based on FAO/WHO standards, the measured heavy metal contents were high for health concern. Produce from areas designated as of low environmental quality, were not necessarily contaminated as perceived. Urban agriculture producers in Nairobi need technical risk reduction measures and legislative support to guarantee quality produce and valuable participation in the urban food system framework.

Assessment of heavy metals and associated oxidative stress in occupationally exposed workers from Bannu and Karak Districts in Pakistan.

Heavy metals (HMs) are extensively found in occupationally exposed miners and industrial workers, which may cause serious health-related problems to the large workforce. In order to evaluate the impact of these toxic pollutants, we have investigated the effect of cadmium (Cd), chromium (Cr), copper (Cu), and lead (Pb) concentration on exposed workers of mining, and woolen textile mill and compared the findings with unexposed individuals. From each category like exposed workers (mining, and woolen mill textile site) and unexposed individuals, 50 blood samples were taken. The occurrence of HMs in a sample was investigated through atomic absorption spectrometry while the oxidative stress marker malondialdehyde (MDA) and antioxidant enzyme statuses such as superoxide dismutase (SOD) and catalase (CAT) were analyzed in exposed and control samples. The results showed significant (p < 0.05) variation in Cd, Cr, Cu, and Pb levels in exposed and control samples. The concentration of Cd in the blood of WMWs, KMWs, and control group was 5.75, 3.89, and 0.42μg/dL, respectively. On the other hand, the concentration of Pb in the blood of WMWs, MWs, and control was 32.34, 24.39, and 0.39µg/dL while the concentrations of Cr and Cu in the blood of WMWs, MWs, and control group were 11.61 and 104.14μg/dL, 4.21 and 113.21μg/dL, 0.32 and 65.53μg/dL, respectively. An increase in MDA was recorded in the exposed workers' group as compared to control subjects, whereas SOD and CAT activities decreased. Meanwhile, MDA was significantly and positively (p < 0.01) correlated with HMs, while negative significant correlations were found among HMs with SOD and CAT.

Occurrence of heavy metals in Qarun Lake and its influence on microbial biodiversity

Occurrence of heavy metals in Qarun Lake and its influence on microbial biodiversity

CONTAMINANT IDENTIFICATION IN WATER BY MICROBIAL BIOSENSORS

The various micro-organisms are used to identify contaminated water. By the help of biosensors, drinking water pollution can be estimated. Rising environmental pollution is badly affecting water. Drinking contaminated water causes serious diseases in human beings as well as in animals.&#x0D; Microorganism in contaminated water can spread serious diseases. Biosensors are genetically modified to identify the occurrence of heavy metals, chemicals and toxins in contaminated water. Different microbes are used as biosensors such as Escherichia coli, Algae, Fungi and Clostridium etc. All these biosensors help to detect water pollution by different ways. For example, algae can detect water contamination by fluorescence during photosynthesis. Most rural areas are being affected by contaminated water. Most of the people living in rural areas are being affected by the polluted water as clean water is not available in these areas. People living in rural areas use water that looks clear but contains micro-pathogens that can cause dangerous diseases. Biosensors are important for identifying contamination, Due biosensor, can easily deduct pollution. Water is very important for the survival.&#x0D; Drinking contaminated water can cause serious illness. Therefore, clean water is very important.

Sources and Risk Characteristics of Heavy Metals in Plateau Soils Predicted by Geo-Detectors

The ecological environment of the remote plateaus has been a challenge plaguing many countries due to global warming, increased human activities, and frequent occurrence of various heavy metal (HM) pollutants. This paper analyzes the primary factors and potential susceptible regions’ characteristics related to soil HMs (As, Cd, Pb, Cr, Ni, and Zn) in the southern Tibet Plateau (TP) using Geo-detectors and a set of multi-source data from remote sensing and geographic and geological information. The geoaccumulation index showed that the As pollution was the most serious. The precipitation, pH, geological age (GA), and rock type (RT) were the most critical factors affecting HMs. Additionally, soil HMs were relatively unaffected by land use and clay. Based on the risk detector, the most key impact types (range) of the predominant factors of HM’s sources were identified. For example, precipitation (100–200 mm), pH (7–7.5), DEM (&gt;5500 m), RT (ophiolite), and GA (Ordovician) had the highest average concentration of As in each type (ranges) of the predominant factors. This work provides new data on the extent of soil HM contamination in the southern TP and predicts vulnerable areas of HM contamination, providing an important scientific basis for monitoring and managing HM in remote areas at high altitudes.

First report on occurrence of heavy metals in dried fishes from major fishing villages in Kerala coast, Southwest India

Heavy metal concentrations in dried fishes collected from four fishing villages of Kerala, India, have been assessed using atomic absorption spectrophotometry. Overall, metal concentrations in dry fishes were in the decreasing order: Zn>Pb>Cu>Cr>Cd. Except Pb and Cr, other metals assessed were within permissible limits. Higher accumulation of Pb may be attributed to anthropogenic sources of metals that are persistent in the southwest coast of India, especially the Kerala coast, due to extensive industrialization, urbanization, fishing and port activities. Thirty-six species of dried fishes collected from Azhikode and Munambam zones were found to have more metal accumulations. The metal pollution assessment of dried fishes indicated that Pb and Cr concentrations are higher in the Kerala coast. Further studies must be carried out in more dried fish species and other preserved seafood to ensure that the dried fishes processed from these polluted coastal zones do not cause any harm to the consumers.

Occurrence and Health Risk Assessment of Heavy Metals in the Blue Land Crab (Cardisoma guanhumi) from a Tropical Mangrove Swamp.

Coastal ecosystems in the Caribbean are vulnerable to pollution from land-based activities with possible impacts to human health. Ten heavy metals in the blue land crab, Cardisoma guanhumi, harvested from the Caroni Swamp, Trinidad, were investigated in the wet and dry seasons. Metal concentrations (µg g-1 dry weight) in crab tissue were: As (0.15-6.46), Ba (0.69-19.64), Cd (< 0.001-3.36), Cr (0.63-3.64), Cu (26.64-120.31), Hg (0.09-1.83), Ni (1.21-9.33), Se (0.19-1.55), V (0.16-0.69) and Zn (121.06-494.3). There were seasonal differences in the concentration of some heavy metals and, Cu and Zn exceeded the local maximum permissible levels for fish and shellfish at several sites in either one or both seasons. Health risk assessment based on estimated daily intake, target hazard quotient and hazard index revealed that Cardisoma guanhumi harvested from the Caroni Swamp, does not pose a health risk to consumers.

Heavy metals assessment of hospital wastewater during COVID-19 pandemic

Hospital wastewater contains heavy metals that threaten environmental and human health through bioaccumulation and biomagnification. Each heavy metal contributes a different impact on human health and the environment. Monitoring the heavy metals in wastewater is essential to prevent those severe impacts. However, it is still rare for a study to assess heavy metals obtained from the discharge of hospital wastewater in Indonesia. Therefore, this study investigated 14 parameters of heavy metals in hospital wastewater. We tested wastewater quality from September 2021 to February 2022, with SNI 6989-59-2008 sampling methods with 14 parameters. Results show that over 14 parameters are still below the threshold value and other previous studies. It might be because the biological treatment used in the hospital wastewater treatment plant (HWWTP) reduces these micropollutants efficiently. The fluidized bed biofilm reactor (FBBR) system is an aerobic process with microorganisms attached to the bio-green. This technique is to form suspensions of solid particles in sparse media with gas streams for chemical or physical processes. The sewage discharge reveals the occurrence of heavy metals in hospital wastewater, even though it does not reveal a high concentration due to the effectiveness of the FBBR system in HWWTP.

Occurrence, Risk, and Source of Heavy Metals in Lake Water Columns and Sediment Cores in Jianghan Plain, Central China.

Heavy metal pollution in lakes is an issue that endangers ecosystems worldwide; however, the vertical properties of heavy metals in the water columns and sediment cores of lakes have been rarely evaluated simultaneously. This study revealed the pollution, risks, and sources of heavy metals from surface water to deep sediments in four typical shallow lakes located in central China. The results showed that the concentrations of heavy metals, except Hg, had insignificant stratification in the water column. Heavy metals had three vertical profiles in sediment cores, i.e., the concentrations of As, Hg, Cd, Pb, and Mn in the surface sediment (0-9 cm) were higher than that in the bottom sediment (9-45 cm) (p < 0.05), the concentrations of Cr, Co, Fe, and Ni in the bottom sediment were higher than the surface sediment (p < 0.05), and the concentrations of Cu and Zn had no significant stratification. The Nemerow pollution index showed that heavy metal pollution dominated by Hg reached slight-moderate levels, and had higher levels in surface water than that in bottom water (p < 0.05). The Nemerow integrated risk index showed that the heavy metals had moderate-extreme potential ecological risks (Cd contributed 43.4%) in the sediments, and the ecological risk in surface sediment was significantly higher than that in bottom sediment (p < 0.01). Principal component analysis revealed that agriculture, transportation, and chemical industry were the major sources of heavy metals in water and surface sediments, while agriculture and steel-making were the primary sources in bottom sediments. This study provides valuable data and insight for the control of heavy metal pollution in lakes with high human activity loads.

Distribution, Multi-Index Assessment, and Sources of Heavy Metals in Surface Sediments of Zhelin Bay, a Typical Mariculture Area in Southern China

The occurrence, multi-index assessment, and sources of heavy metals in surface sediments of Zhelin Bay were investigated. Average heavy metal concentrations (mg/kg) were 81.89 (Cr), 770.76 (Mn), 16.81 (Co), 62.25 (Ni), 96.30 (Cu), 162.04 (Zn), and 73.40 (Pb), with the concentrations of studied seven heavy metals being significantly higher than their corresponding background values. Geo-accumulation index (Igeo) and pollution load index (PLI) were implemented to assess degree of heavy metal contamination. The Igeo and PLI indicated that Cr, Mn, Co, Zn, and Pb were slightly polluted, and Cu and Ni were moderately polluted in the region. Potential ecological risk index (RI) and mean possible effect level (PEL) quotient were conducted to assess ecological risk. The RI and mean PEL quotient demonstrated that surface sediments of Zhelin Bay were slight ecological risks and exhibited a 21% probability of toxicity. Principal component analysis (PCA) combined with the correlation analysis (CA) and hierarchical cluster analysis (HAC) revealed that the heavy metal contamination in Zhelin Bay might originate from three type sources.

Occurrence and impact of heavy metals on environment

Heavy metals are introduced into the environment by naturally occurring phenomenon like volcanic eruption, rock weathering and many more. As well as by human activities are also equally engaged in the contamination of the environment such as industrial discharge, excessive automotive use, resource extraction, metallurgy, anthropogenic activities, metallurgy, and so on. Because of the dramatic increase in health hazards that is directly associated with vital heavy metal exposure. Though many heavy metals are vital for survival on Earth, they can also have a negative and significant impact on all living bodies (such as plants, animals, and microorganisms). They can damage tissues and even lead to severe organ damage/impairment, the functioning of some organs can also be severely affected, neurological disorders can eventuate, and even lead to death. Heavy metal even adds adverse effect on the function of reproduction like drastic change in sperm, count in males, imbalance of hormones, motility etc. Efficiency of reproduction is get affected by hazardous heavy metals. Toxicity factor depend on various subfactors like the amount of consumption (dose), route, age group, and other genetics parameters. These toxicants can induce efficiency of multiple organs, though at low dosage or exposure.

Heavy Metal Content and Resistance Gene Abundance and Related Properties in the Surface Soil around Qinghai Lake

Soil heavy metal pollution and the prevalence of resistance genes have been a global concern, and thus many studies have reported the content of heavy metals and resistance genes in soils; however, the contents of heavy metals and antibiotic resistance genes (ARGs) in the soil in highland areas is still unclear. In this study, the environmental residues and distribution of heavy metals and resistance genes in the soil in Qinghai were analyzed, and the relationship between the concentration of heavy metals and antibiotic resistance genes in the soil was explored. Among the soil samples, the content of heavy metal zinc was the highest ［mean: (50.27±19.88) mg·kg-1］, followed by the content of heavy metal cadmium ［mean: (30.27±9.45) mg·kg-1］, and the content of heavy metal mercury was the lowest ［mean: (0.027±0.019) mg·kg-1］. The subtypes of heavy metal resistance genes in soils were mainly czcA, merA, and merP, whose main function was to be responsible for developing mercury resistance. The relative abundance of β-lactamase resistance genes (0.1505) was the highest in soil, accounting for 47.54% of the total abundance of ARGs; tetracycline resistance genes accounted for 16.93% of the total abundance of ARGs, FCA accounted for approximately 14.56%, and MLSB accounted for approximately 8.77%. The diversity and relative abundance of movable genetic elements (MGEs) were low, and only the [STBX]tnpA01[STBZ] gene was detected; intl[STBX]1[STBZ] and intl[STBX]2[STBZ] were not detected. Correlation studies showed that Cu content (r=-0.533, P=0.006) and Hg (r=0.692, P=0.006) in soil were significantly negatively correlated with altitude, whereas other heavy metals were not significantly correlated with altitude. In addition, heavy metal content was significantly correlated with soil type (P<0.05). There was a significant positive correlation between heavy metal mercury content in soils and czcA (r=0.692, P=0.006), merA (r=0.816, P=0.007), and merP (r=0.594, P=0.02). The results of this study elucidated the occurrence and distribution of heavy metals and ARGs in the Tibetan Plateau region and found that the content of heavy metals in the soil was significantly related to resistance genes.

Occurrence of Heavy Metals in Wines for 13 European Countries: A Short Review

Occurrence of Heavy Metals in Wines for 13 European Countries: A Short Review

Assessing the Occurrence of Heavy Metals in Edible Fruits Grown around Mine Tailings Dam in Kitwe

Mining activities in the Copperbelt province of Zambia have been of great environmental concern, despite recorded improvements in the socio-economic sector. Heavy metal contamination of soils resulting from depositing mine tailings and rock waste has posed possible health risks for communities nearer such facilities. The current study was conducted around residential homes surrounding Kitwe slimes (TD25). This work investigated levels of Co, Cu, Fe, Mn and Pb in the soils, and avocado and lemons fruits, growing near TD25. Heavy metals were analyzed using Atomic Absorption Spectrophotometer. The work further assessed the estimated daily intake (EDI) associated with potential health risks to humans. In the soil, concentration levels of heavy metals showed a trend in the order: Fe > Cu > Mn > Co > Pb. Heavy metal contents in avocado and lemon fruits at 200 and 400 m away from TD25, all had p-values -1 (avocado) and 0.14 mg·kg-1 (lemon), though both results were far below the FAO/WHO standard range (12.5 - 19.6 mg·kg-1). For both fruits, Co and Pb results were negligible. The concentration of the five heavy metals in avocado and lemon fruits grown around Kitwe slimes did not pose any health risks to the consumers.

Heavy metals occurrence in lakes of the Danube Delta, Romania

Heavy metals occurrence in lakes of the Danube Delta, Romania

Occurrence and Distribution of Heavy Metals in Mining Degraded Soil and Medicinal Plants: A Case Study of Pb/Zn Sulfide Terrain Northern Areas, Pakistan

Mining activities have serious environmental impacts, thus releasing heavy metals (HMs) such as cadmium (Cd), lead (Pb), chromium (Cr), zinc (Zn) and nickel (Ni) into the surrounding environment. The current paper investigated the impacts of mining activities of Pb-Zn sulfide on soil and medicinal plants. Hence, soil samples (n = 36) and medicinal plants (n = 36) samples were collected, acid extracted and were analyzed through Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for HMs quantification. Our results showed that mineralized zones showed high HMs enrichment levels as compared to non-mineralized zones. Various Indices for HMs assessment revealed that the contaminated soil of the study area had low to extreme level. The mean concentrations of HMs in mining degraded soil and medicinal plants were significantly higher (p ≤ 0.01) and were found in order of Zn > Pb > Cr > Ni > Cd and Cr > Zn > Pb > Ni > Cd respectively. Similarly, some widely consumable medicinal plants showed good metal accumulation for Cd, Cr and Pb i.e., 3.57mg kg1, 350mg kg-1 and 335mg kg-1 in C. sativa, while 5.9mg kg-1, 276.9mg kg-1 and 188.7mg kg-1 in R. hestatus respectively. Hence, the present study recommended that medicinal plants grown in mining areas should be analyzed for HMs concentration before consumption.