Environmental metal contamination and health impact assessment in two industrial regions of Romania

Response of Carrot (Daucus carota L.) to Multi-Contaminated Soil from Historic Mining and Smelting Activities

A pot experiment was undertaken to investigate the effect of Cd, Pb and Zn multi-contamination on the physiological and metabolic response of carrot (Daucus carota L.) after 98 days of growth under greenhouse conditions. Multi-contamination had a higher negative influence on leaves (the highest Cd and Zn accumulation) compared to the roots, which showed no visible change in terms of anatomy and morphology. The results showed the following: (i) significantly higher accumulation of Cd, Zn, and Pb in the multi-contaminated variant (Multi) compared to the control; (ii) significant metabolic responses-an increase in the malondialdehyde content of the Multi variant compared to the control in the roots (by 20%), as well as in the leaves (by 53%); carotenoid content in roots decreased by 31% in the Multi variant compared with the control; and changes in free amino acids, especially those related to plant stress responses. The determination of hydroxyproline and sarcosine may reflect the higher sensitivity of carrot leaves to multi-contamination in comparison to roots. A similar trend was observed for the content of free methionine (significant increase of 31% only in leaves); (iii) physiological responses (significant decreases in biomass, changes in gas-exchange parameters and chlorophyll a); and (iv) significant changes in enzymatic activities (chitinase, alanine aminopeptidase, acid phosphatase) in the root zone.

New method for risk assessment in environmental health: The paradigm of heavy metals in honey

The release of heavy metals into the natural environment creates problems due to their persistence. They can accumulate in the food chain presenting a dangerous sign for ecosystems and human health. The metals in honey could be of agrochemical or industrial origin. Regular consumption of honey and bee products contaminated with various pollutants in high concentrations can cause serious health problems due accumulation of toxic substances in the body. In the current study, we aimed to determine the concentrations of chromium, cadmium, zinc, copper, lead and nickel in four types of honey (linden, acacia, rapeseed and polyfloral honey) and soil collected from three regions with different degrees of pollution. For the risk characterization, we used a new methodology that calculated the corrected estimated daily intake and the source hazard quotient for each metal and the adversity-specific hazard index. There was a strong influence of the degree of environmental pollution on the level of contaminants in the honey samples. In the case of a single chemical assessment, an HQ above 10 was obtained for Cd in linden, rapeseed and polyfloral honey from area 1 and an HQ above 1 was obtained for Cd in the other honey samples from the 3 areas, for Cu in all honey samples from all the 3 areas, for Pb in linden, rapeseed and polyfloral honey from area 1 and for Cr in linden honey for area 2. HIA calculated as a sum of all HQS of heavy metals in food reveals an increase and moderate risk for nephrotoxicity, bone demineralisation, cardiotoxicity, developmental toxicity, small decrease in body weight or body weight gain after consumption of honey impurified with heavy metals. A strict monitorization of heavy metals in honey samples from farmers should be done in order to protect the consumers.

Co-application of citric acid and Nocardiopsis sp. strain RA07 enhances phytoremediation potentiality of Sorghum bicolor L

This study investigated the combined effects of citric acid (CA) and Nocardiopsis sp. RA07 on the phytoremediation potential of lead (Pb)- and copper (Cu)-contaminated soils by Sorghum bicolor L. The strain RA07 was able to tolerate Pb and Cu, and exhibited plant growth-promoting features like siderophore production, indole-3-acetic acid (IAA) synthesis, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity and phosphate solubilization. The combined application of CA and strain RA07 significantly increased S. bicolor growth, chlorophyll content and antioxidant enzymatic activity, and decreased oxidative stress (hydrogen peroxide and malondialdehyde content) under Pb and Cu stress circumstances as compared to individual treatments (i.e., CA and strain RA07). Furthermore, the combined application of CA and RA07 significantly enhanced S. bicolor ability to accumulate Pb and Cu by 64.41% and 60.71% in the root and 188.39% and 125.56% in the shoot, respectively, as compared to the corresponding uninoculated plants. Our results indicate that inoculation of Nocardiopsis sp. together with CA could be a useful practical approach to mitigate Pb and Cu stress on plant growth and increase the effectiveness of phytoremediation in Pb- and Cu-polluted soils.

Metal-immobilizing Pseudomonas taiwanensis WRS8 reduces heavy metal accumulation in Coriandrum sativum by changing the metal immobilization-related bacterial population abundances

Metal-immobilizing bacteria play a critical role in metal accumulation in vegetables. However, little is known concerning the mechanisms involved in bacteria-induced reduced metal availability and uptake in vegetables. In this study, the impacts of metal-immobilizing Pseudomonas taiwanensis WRS8 on the plant biomass, Cd and Pb availability and uptake in two coriander (Coriandrum sativum L.) cultivars, and bacterial community structure were investigated in the polluted soil. Strain WRS8 increased the biomass of two coriander cultivars by 25-48% and reduced Cd and Pb contents in the edible tissues by 40-59% and available Cd and Pb contents in the rhizosphere soils by 11.1-15.2%, compared with the controls. Strain WRS8 significantly increased the pH values and relative abundances of the dominant populations of Sphingomonas, Pseudomonas, Gaiellales, Streptomyces, Frankiales, Bradyrhizobium, and Luteimonas, while strain WRS8 significantly decreased the relative abundances of the dominant populations of Gemmatimonadaceae, Nitrospira, Haliangium, Paenibacillus, Massilia, Bryobacter, and Rokubacteriales and the rare bacterial populations of Enterorhabdus, Roseburia, Luteibacter, and Planifilum in the rhizosphere soils, compared with the controls. Significantly negative correlations were observed between the available metal concentrations and the abundances of Pseudomonas, Luteimonas, Frankiales, and Planifilum. These results implied that strain WRS8 could affect the abundances of the dominant and rare bacterial populations involved in metal immobilization, resulting in increased pH values and decreased metal availability and uptake in the vegetables in the contaminated soil.

Assessment of Heavy Metal Content in Soil and Lycopersicon esculentum (Tomato) and Their Health Implications

In this study, the content of lead (Pb), cadmium (Cd), chromium (Cr) and manganese (Mn) was evaluated in soils and tomatoes (Lycopersicon esculentum) collected from rural areas of Dobrogea province, South-East of Romania. The risk to human health due to the heavy metal exposure via tomato consumption was also assessed.The results suggest that based on the contamination factor, the soils are moderately contaminated with Cd and Mn (Cf values of 1.266. and 1.40) and poorly contaminated with Pb and Cr. The bioconcentration factor (BAF) was below 1 and indicated that the studied species of Lycopersicon esculentum did not accumulate the monitored elements. Person's correlation analysis showed that there were significant relations between soil pH and BCF values of Cd, Pb, Cr and Mn in analysed tomatoes. The estimated daily intake of each metal was below the oral reference dose. The hazard quotient (HQ) and hazard index (HI) were below the acceptable level (< 1), and the cancer risk (CR) for Pb, Cd and Cr was found within acceptable levels (1.0 × 10^-6-1.0 × 10^-4). Based on health guidance values, it may be concluded that the analysed tomatoes do not present health risks to consumers in terms of content and accumulation of heavy metals. It is important to monitor the other toxic metals as well, in order to evaluate the heavy metal accumulation variation and the toxicity value of each metal in agricultural soils from both rural and industrial areas.

Machine learning based on the graph convolutional self-organizing map method increases the accuracy of pollution source identification: A case study of trace metal(loid)s in soils of Jiangmen City, south China

Rapid economic development and industrialization may include environmentally harmful human activities that cause heavy-metal accumulation in soils, ultimately threatening the quality of the soil environment and human health. Therefore, accurate identification of pollution sources is an important weapon in efforts to control and prevent pollution. The self-organizing map (SOM) method is widely used in pollution source identification because of its capacity for visualization of high-dimensional data. The SOM ignores the graph structure relationship among chemical elements in soils; the SOM analysis of pollution sources has high uncertainty. Here, we propose a new analysis method, i.e., the graph convolutional self-organizing map (GCSOM), which uses a graph convolutional network (GCN) to extract the graph structure relationship among the chemical elements in soils, then performs data visualization using an SOM. We compared the performances of GCSOM and SOM, then assessed the pollution source characteristics of trace metal(loid)s (TMs, mostly heavy metals) in Jiangmen City using the GCSOM. Our experimental results showed that the GCSOM is superior to the SOM for identification of TM sources, while the TMs in the soil of Jiangmen originate from three main sources: agricultural activities (mainly in Taishan City, Jiangmen), traffic emissions (mainly in Xinhui and Pengjiang Districts), and industrial activities (mainly in Xinhui District). The risk assessment indicated that the risk of all TMs was within threshold.

Environmental Controls to Soil Heavy Metal Pollution Vary at Multiple Scales in a Highly Urbanizing Region in Southern China

Natural and anthropogenic activities affect soil heavy metal pollution at different spatial scales. Quantifying the spatial variability of soil pollution and its driving forces at different scales is essential for pollution mitigation opportunities. This study applied a multivariate factorial kriging technique to investigate the spatial variability of soil heavy metal pollution and its relationship with environmental factors at multiple scales in a highly urbanized area of Guangzhou, South China. We collected 318 topsoil samples and used five types of environmental factors for the attribution analysis. By factorial kriging, we decomposed the total variance of soil pollution into a nugget effect, a short-range (3 km) variance and a long-range (12 km) variance. The distribution of patches with a high soil pollution level was scattered in the eastern and northwestern parts of the study domain at a short-range scale, while they were more clustered at a long-range scale. The correlations between the soil pollution and environmental factors were either enhanced or counteracted across the three distinct scales. The predictors of soil heavy metal pollution changed from the soil physiochemical properties to anthropogenic dominated factors with the studied scale increase. Our study results suggest that the soil physiochemical properties were a good proxy to soil pollution across the scales. Improving the soil physiochemical properties such as increasing the soil organic matter is essentially effective across scales while restoring vegetation around pollutant sources as a nature-based solution at a large scale would be beneficial for alleviating local soil pollution.

Heavy metals and health risk assessment in vegetables grown in the vicinity of a former non-metallic facility located in Romania

Soil contamination represents a serious and significant issue, especially when it comes to soil used in agricultural practices. This research was carried out in order to investigate the accumulation level of potentially toxic trace elements (Cr, Cd, Cu, Mn, Ni, Pb and Zn) in soil and vegetables (Solanum lycopersicum and Daucus carota). The transfer of the trace elements from soil to vegetables and the potential risk assessment were studied as well. Results indicated relatively high levels of heavy metals. Cd, Cu and Pb exceeded the alert limits established by the Romanian legislation. Zn was high as well. Positive correlations between the Cr, Cu and Pb indicated similar source of pollution, possibly related to the activities occurred in the non-metallic facility, nearby the study area. The heavy metals determined in the Solanum lycopersicum fruits and Daucus carota roots were below the maximum allowable concentrations, according to the WHO/FAO guideline. Slightly higher amounts of Cr and Cu were measured in tomatoes, compared to the carrots. Nevertheless, carrots were richer in Ni and Mn. The applied pollution indices indicated a contamination with heavy metals in 90% of the soil samples, with 9% probability of toxicity, the remaining 10% being classified into the precaution domain category. The plant bioconcentration of heavy metals into the Solanum lycopersicum fruits and Daucus carota roots is characterized using transfer factors. Generally, the results indicate that Daucus carota was the most susceptible to uptake Cu and Mn, while Solanum lycopersicum would rather uptake Cd and Zn. The estimated non-carcinogenic risk, based on the human health risk indices, indicates that the studied vegetables are safe for consumption with no impact on the human health. The results are lower than the critical value. Similarly, the carcinogenic risk indices results showed acceptable risks of cancer developing. It is important to assess and monitor the heavy metals levels in soil and in the vegetables intended to be consumed, in order to prevent contamination and potential negative effects on the environment and implicitly on the human health. The obtained data can be used in remediation techniques, as well as in implementing control measures of heavy metal contamination in soil and vegetables.

Attention deficit among preschool and school-aged children living near former metal-processing plants in Romania

Industrial areas affected by high and long-term heavy metal pollution have a great impact on health of the resident population. Children represent a group at high-risk with an increased susceptibility to chronic heavy metal intoxication. Our work included the assessment of attention particularities through a case-control study in pre-school and school-aged children (4-6 years and 8-11 years) from two study areas, Copşa Mică and Zlatna, compared to a non-polluted locality with no history of heavy metal pollution. Copşa Mică and Zlatna are two of the most polluted heavy metals regions in Romania due to non-ferrous metallurgy for a long period of time. Recruitment of participants was made by a random selection of an entire class for each age within the schools and kindergartens from the study areas (Copşa Mică and Zlatna) and from the non-polluted region. Interpretation of data was performed using statistical analysis (ANOVA and Student's t-test). Preschool children (4-6 years) were tested using Wechsler Preschool and Primary Scale of Intelligence (WPPSI) tests, Animal House and labyrinth samples. The results of the attention tests applied to pre-school children were lower in the study areas compared to the control group, but no statistical differences were found. The results of the attention tests applied to children aged between 8 and 11 years (Toulouse-Pieron test and Traffic light test) indicate lower average scores within the study groups from polluted areas, compared to the control group. Differences with statistically significance were registered for the 8 years age group (p = 0.037). In these areas efficient strategies and precise intervention measures are needed in order to limit or remove the heavy metal exposure and protect the human health, especially the groups exposed to a high level of risk.

Isolation of heavy metal-immobilizing and plant growth-promoting bacteria and their potential in reducing Cd and Pb uptake in water spinach

Heavy metal-immobilizing bacteria are normally capable of stabilizing metals and affecting their absorption by plants. However, few studies have elucidated the mechanisms employed by novel heavy metal-immobilizing and plant growth-promoting bacteria to immobilize Cd and Pb and reduce their uptake by vegetables. In this study, polyamine (PA)-producing strains were isolated and their effects on biomass and metal accumulation in water spinach (Ipomoea aquatica Forssk.) and the underlying mechanisms were investigated. Two PA-producing strains, Enterobacter bugandensis XY1 and Serratia marcescens X43, were isolated. Strains XY1 and X43 reduced the aqueous Cd and Pb levels (49%-52%) under 10 mg L^-1 Cd and 20 mg L^-1 Pb because of metal ion chelation by bacterially produced PAs and cell adsorption. Further evidence showed that Cd and Pb were bound and precipitated on the bacterial cell surface in the form of Cd(OH)₂, CdCO₃ and PbO. Compared with strain-free water spinach, greens inoculated with strains XY1 and X43 showed 51%-80% lower Cd and Pb contents. The rhizosphere soil pH and PA contents were significantly higher, and lower contents of the rhizosphere soil acid-soluble fractions of Cd (18%-39%) and Pb (31%-37%) were observed compared to the noninoculated control. Moreover, inoculation with XY1 reduced the diversity of the bacterial community, but the relative abundances of plant growth-promoting and PA-producing bacteria in rhizosphere soil were enriched, which enhanced water spinach resistance to Cd and Pb toxicity. Our findings describe novel heavy metal-immobilizing bacteria that could be used to improve the habitat of vegetables and reduce their uptake of heavy metals.

Black Sea Mussels Qualitative and Quantitative Chemical Analysis: Nutritional Benefits and Possible Risks through Consumption

Mussels have a particular nutritional value, representing a highly valued food source and thus sought after worldwide. Their meat is a real culinary delicacy, rich in proteins, lipids, carbohydrates, trace elements, enzymes, and vitamins. The seasonal variation of mussels’ biochemical composition has been studied to determine the best harvesting period to capitalize on various biologically active fractions. In this work biochemical determinations have been performed on fresh flesh samples of Mytilus galloprovincialis specimens from the Black Sea coast to study seasonal variations in mussels’ biochemical compounds. An analysis of significant lipid classes and the fatty acid composition of lipid extracts obtained from mussel flesh has also been performed. Since mussels retain pollutants from the marine environment, in parallel, the concentration of heavy metals in the meat of mussels collected for the analysis of the chemical composition was investigated. The impact and risk of heavy metal poisoning due to food consumption of mussels contaminated due to pollution of the marine harvesting area was evaluated by the bio-concentration factor of metals and estimated daily intakes of heavy metals through mussel consumption.

Quality Control of Different Types of Honey and Propolis Collected from Romanian Accredited Beekeepers and Consumer’s Risk Assessment

Honey is a natural product recognized and appreciated for its nutritional value and therapeutic potential. However, the quality of bee honey is essential because various contaminants can seriously affect consumers’ health. In the experimental part of the work, we analyzed different types of honey (linden, black locust, rapeseed and multifloral honey) and propolis, which were collected from Romanian accredited beekeepers who placed beehives in two areas characterized by different industrial activity: area 1 (A1) is an area with intense industrial activity, with other industries existing nearby, including a refinery, while area 2 (A2) is entirely devoid of industrial activity, but with moderate agricultural activity. A total of 144 samples were collected, twelve samples for each variety of honey, propolis and soil, corresponding to each area analyzed. In addition, seven heavy metals and three pesticides were tested for in the samples collected. Finally, the correlation between the degree of contamination with soil pollutants and the contamination of the bee products harvested from the analyzed areas was studied. Cadmium, lead, copper, zinc and the sum of DDT metabolites exceeded the maximum allowable levels in honey samples, with differences between different types of honey.

Terrain-modulated deposition of atmospheric lead in the soils of alpine forest, central China

Alpine ecosystem has a potential to intercept the transport of atmospheric metals, while the regulation mechanisms with variations in altitude and slope direction remain unclear. In this study, the soil and moss samples on the northern and southern slopes of Shennongjia Mountain were collected with altitude to quantitatively identify the sources of lead (Pb) and to decipher the regulation mechanisms of altitude and slope on the Pb distribution. The results showed that the concentrations of Pb decreased evidently with soil depth, and in the O (organic soils) and A (surface mineral soils) horizons they increased with altitude. The Pb isotopes and moss biomonitoring revealed that Pb was mainly from atmospheric deposition, and the sources included fossil fuel combustion, ore mining and smelting. Based on a binary mixing model of Pb isotopes, the percentage of atmospheric Pb in the O and A horizons and mosses averaged 58.8%, 43.7% and 71.0%, respectively. Atmospheric wet deposition strikingly controlled the distribution of soil Pb along the altitude. Canopy filtering and leaching also impacted the accumulation of Pb in the forest floor. The significant difference in the atmospheric Pb accumulation in the soils between the two slopes was not observed as expected, since atmospheric dry deposition from northwestern China contributed to the Pb accumulation on the northern slope according to the Pb isotopic ratios and air mass trajectories. The results of this study indicate that altitude determines the distribution pattern of atmospheric Pb, while slope direction screens the source region of Pb in alpine ecosystems.

Evaluating the health risks of heavy metals from vegetables grown on soil irrigated with untreated and treated wastewater in Arba Minch, Ethiopia

Available freshwater scarcity significantly affects sustainable food production for the rapidly growing population. This problem has forced people in most parts of the world to use wastewater as a viable solution. However, wastewater reuse has some deleterious effects on human and environmental health. This study was designed to investigate the health risks (HRs) of heavy metals (HMs) from vegetables irrigated with untreated and treated wastewater. The composite wastewater was collected at various sites in Arba Minch town and subjected to aerobic-anoxic treatment. Treated and untreated wastewater (UTW) was used to irrigate vegetables (lettuce, cabbage and tomato), and HM results were compared with the control (tap water) and standards. Water, soil and vegetables were investigated for various physical and chemical properties. Human health effects due to vegetable consumption were analyzed using HR- index (HRI), target hazard quotient (THQ) and hazard index (HI). The results revealed that most of the water quality indexes were significantly enhanced after aerobic-anoxic treatment, suggesting that wastewater collected from different sites was suitable for biodegradation. Soil physicochemical analyses also showed that pH, cation exchange capacity, organic carbon and organic matter were higher for UTW irrigated soil. Heavy metal concentrations were relatively greater in soils than water used for irrigation purposes and vegetables. The HM concentration in vegetables was higher for UTW than for treated and tap water irrigated vegetables. In vegetables, the order of HM content was Fe > Mn > Zn > Pb > Cu > Cd. Tomato followed by cabbage and lettuce accumulated significant amount of HMs (Fe > Mn > Zn > Pb > Cu > Cd) in their different organs (fruit/leaf>root>stem). The individual and combined health indexes (HRI, THQ and HI) showed that Pb and Cd have values greater than unity for wastewater irrigated vegetables, which could result in non-carcinogenic disease for short/lifetime exposure in adults and children. Overall, consumption of vegetables can be safer when grown with treated effluent than with UTW.

Stochastic risk assessment of urban soils contaminated by heavy metals in Kazakhstan

Kazakhstan's growing economy has been posing a threat to the natural environment in the country. The study aimed to investigate the status of soil contamination by five heavy metals (Pb, Cd, Cu, Zn, and Cr) in Kazakhstan during 2010-2018 as well as its impact on the population. Data for the analysis were collected from the governmental monitoring agency, which has reported the concentrations of five heavy metals in the Kazakhstan soil each year. Preliminary screening suggested the four most contaminated cities (Balkhash, Ust-Kamenogorsk, Ridder, and Shymkent). Mean soil concentrations in these cities varied between 251 and 442 mg/kg for Pb, 5-9 mg/kg for Cd, 8-138 mg/kg for Cu, 87-178 mg/kg for Zn, and 2-5 mg/kg for Cr. Analysis of geo-accumulation index pointed out the possible anthropogenic origin of the contamination by Pb and Cd in these cities (mean I_geo was 3.81 for Pb and 3.45 for Cd). Further probabilistic risk assessment for these cities demonstrated that mean hazard indices for children fluctuated between 1 and 2 in two cities (Shymkent and Balkhash), whereas cancer risks for both age groups stayed in the range of 1 × 10^-6 and 5 × 10^-6, indicating that soil remediation is urgently required for the health of the citizens and environments. Both ~60-90% of adults and ~30-60% of children cases exceeded the threshold of carcinogenic assessment (1 × 10^-6), suggesting that a large portion of the population in these cities could be affected by heavy metals in soil. The study provides background understanding for decision making on remediation actions and environmental policy and hazardous waste management in Kazakhstan.

Exposure to cadmium and copper triggers cytotoxic effects and epigenetic changes in human colorectal carcinoma HT-29 cells

Recent scientific evidence suggests a link between epigenetic changes (DNA methylation) and tumorigenesis. Moreover, a potential carcinogenic mechanism of cadmium was associated with changes in DNA methylation. In this study we investigated the impact of CdCl₂ and CuSO₄ aqueous solutions on DNA methylation in HT-29 cells by quantifying DNA methyltransferase (DNMT1, DNMT3A and DNMT3B) mRNA expression. Furthermore, we also studied the cytotoxic and anti-migratory potential of these substances. The results showed a dose-dependent decrease of viable cell percentage following 24 h of exposure (at concentrations of 0.05; 0.2; 1; 10 and 100 µg/ml), and an inhibitory effect on HT-29 cell migration capacity. In addition, RT-qPCR results showed that cadmium acts as a hypomethylating agent by suppressing DNMT expression, whereas copper acts as a hypermethylating compound by increasing DNMT expression. These findings suggest a cytotoxic potential of both cadmium and copper on HT-29 cells and their capacity to induce epigenetic changes.

Heavy metal and pesticide levels in dairy products: Evaluation of human health risk

Cattle milk's health benefits can be compromised by the presence of contaminants. The levels of cadmium, copper, lead and zinc, and residues of dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD), dichlorodiphenyltrichloroethane (DDT) were determined in soil, milk and cheese samples collected from cow farms from 3 Romanian areas with industrial and agriculture tradition. A new methodology was applied for the determination of the corrected estimated daily intake (cEDI) corresponding to the aggregate dietary exposure. For the risk assessment, we calculated the source hazard quotient (HQs) for each contaminant and the adversity specific hazard index (HIA). Cadmium, copper, lead and zinc, and the sum of DDT levels in soil samples were below maximum residue levels (MRLs). The MRLs of lead and DDD were exceeded in milk and cheese samples from all the 3 areas. The MRLs of copper and zinc were exceeded in cheese samples from area 2 and 3. HQs >10 for lead indicates increased risk, while HQ > 1 for copper and sum of DDT indicates moderate risk for both milk and cheese. By calculating the HI_A, we identified a moderate and increase risk for nephrotoxicity, hepatotoxicity, hematotoxicity, cardiotoxicity and reproduction toxicity after consumption of the dairy products from the 3 areas.

Spatiotemporal patterns and drivers of soil contamination with heavy metals during an intensive urbanization period (1989-2018) in southern China

This three-decade long study was conducted in the Pearl River Delta (PRD), a rapidly urbanizing region in southern China. Extensive soil samples for a diverse land uses were collected in 1989 (113), 2005 (1384), 2009 (521), and 2018 (421) for heavy metals of As, Cr, Cd, Cu, Hg, Ni, Pb and Zn. Multiple pollution indices and Structural Equation Models (SEMs) were used in attribution analysis and comprehensive assessments. Data showed that majority of the sampling sites was contaminated by one or more heavy metals, but pollutant concentrations had not reached levels of concerns for food security or human health. There was an increasing trend in heavy metal contamination over time and the variations of soil contamination were site-, time- and pollutant-dependent. Areas with high concentrations of heavy metals overlapped with highly industrialized and populated areas in western part of the study region. A dozen SEMs path analyses were used to compare the relative influences of key environmental factors on soil contamination across space and time. The high or elevated soil contaminations by As, Cr, Ni, Cu and Zn were primarily affected by soil properties during the study period, except 1989-2005, followed by land use patterns. Parent materials had a significant effect on elevated soil contamination of Cd, Cr, Ni, Pb and overall soil pollution during 1989-2005. We hypothesized that other factors not considered in the present study, such as atmospheric deposition, sewage irrigation, and agrochemical uses, may be also important to explain the variability of soil contamination. This study implied that strategies to improve soil physiochemical properties and optimize landscape structures are viable methods to mitigate soil contamination. Future studies should monitor pollutant sources identified by this study to fully understand the causes of heavy metal contamination in rapidly industrialized regions in southern China.

Toxic-Metal-Induced Alteration in miRNA Expression Profile as a Proposed Mechanism for Disease Development

Toxic metals are extensively found in the environment, households, and workplaces and contaminate food and drinking water. The crosstalk between environmental exposure to toxic metals and human diseases has been frequently described. The toxic mechanism of action was classically viewed as the ability to dysregulate the redox status, production of inflammatory mediators and alteration of mitochondrial function. Recently, growing evidence showed that heavy metals might exert their toxicity through microRNAs (miRNA)—short, single-stranded, noncoding molecules that function as positive/negative regulators of gene expression. Aberrant alteration of the endogenous miRNA has been directly implicated in various pathophysiological conditions and signaling pathways, consequently leading to different types of cancer and human diseases. Additionally, the gene-regulatory capacity of miRNAs is particularly valuable in the brain—a complex organ with neurons demonstrating a significant ability to adapt following environmental stimuli. Accordingly, dysregulated miRNAs identified in patients suffering from neurological diseases might serve as biomarkers for the earlier diagnosis and monitoring of disease progression. This review will greatly emphasize the effect of the toxic metals on human miRNA activities and how this contributes to progression of diseases such as cancer and neurodegenerative disorders (NDDs).

Heavy metals contamination in soil, surface water, crops, and resident blood in Uthai District, Phra Nakhon Si Ayutthaya, Thailand

This study evaluates the heavy metal (As, Cd, Cu, Hg, Pb, and Zn) contamination in soil, surface water, and crops in Uthai District, Ayutthaya Province, Thailand, an agricultural area located near an industrial park. Further, the blood levels of these metals in residents living in the study area are investigated. The concentrations of the six metals in soil were below the values permitted under the Soil Quality Standard, Thailand. In contrast, the concentrations of As and Hg in surface water exceeded the permissible limits. For the crops, all heavy metal values in eggplant, kale, and rice were at safe levels. However, in basil, both Hg and Cu levels exceeded the permissible limits, and in coriander, Hg content exceeded the permissible limit. Additionally, the potential health risks of heavy metal exposure through consumption of local crops were assessed using target hazard quotients (THQs) and hazard indices (HIs). The former values of the crops varied. 100.0% for As, 40% for Cd, 60% for Cu, 20% for Pb, and 30% for Zn of the analyzed samples had THQs above 1. This indicated that consumers were probably exposed to some non-carcinogenic health risk (except for Hg which was 0%). Of greater concern, the HI values of each consumed crop were > 1, indicating obvious risk of adverse health effect. Finally, the heavy metal levels in blood from a sample of local residents (n = 16) were assessed along with blood chemistry tests. The levels of all heavy metals were within the normal ranges. Nevertheless, heavy metal contamination in both the environment and food crops raise concerns of health risks to the residents of this area.

Human health risks by potentially toxic metals in drinking water along the Hattar Industrial Estate, Pakistan

This study aimed to investigate the contamination of drinking water sources with potentially toxic metals (PTMs) together with some hydrochemical characteristics in the highly populated industrial zone of Pakistan. For this purpose, drinking (n = 40) and surface (n = 20) water samples were collected and analyzed for PTM using graphite furnace atomic absorption spectrophotometer (GFAAS, PerkinElmer-700, USA). The metals, including cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), and zinc (Zn), showed significantly (p = 0.05) higher concentrations than their respective limits set by the World Health Organization (WHO 2011) in drinking water. The chronic daily intake (CDI) and human hazard quotient (HQ) were also evaluated. The highest daily intake through drinking water consumption was found for Ni (4.3 μg/kg/day), while lowest for Cd (0.25 μg/kg/day). The highest hazard quotient values were found for Cd (0.33) and Ni (0.29) that could be attributed to industrial wastewater discharge. Higher CDI and HQ values of Ni and Cd may cause chronic human health problems. According to the Chadha Piper diagram, the hydrochemical facies distribution indicated that water trend in the study area followed an order such as follows: Ca-Mg-Cl < Na-Cl < Ca-HCO₃ < Na-HCO₃. Statistical analysis using one-way ANOVA, correlation analysis, and principal component analysis (PCA) revealed that the elevated levels of PTM were attributed to industrial wastewater discharge. This study provides baseline information for policy makers and the effective management of water in populated industrialized zone.

Environmental Chemical Contaminants in Food: Review of a Global Problem

Contamination by chemicals from the environment is a major global food safety issue, posing a serious threat to human health. These chemicals belong to many groups, including metals/metalloids, polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), perfluorinated compounds (PFCs), pharmaceutical and personal care products (PPCPs), radioactive elements, electronic waste, plastics, and nanoparticles. Some of these occur naturally in the environment, whilst others are produced from anthropogenic sources. They may contaminate our food-crops, livestock, and seafood-and drinking water and exert adverse effects on our health. It is important to perform assessments of the associated potential risks. Monitoring contamination levels, enactment of control measures including remediation, and consideration of sociopolitical implications are vital to provide safer food globally.

Combining emission inventory and isotope ratio analyses for quantitative source apportionment of heavy metals in agricultural soil

Two quantitative methods (emission inventory and isotope ratio analysis) were combined to apportion source contributions of heavy metals entering agricultural soils in the Lihe River watershed (Taihu region, east China). Source apportionment based on the emission inventory method indicated that for Cd, Cr, Cu, Pb, and Zn, the mean percentage input from atmospheric deposition was highest (62-85%), followed by irrigation (12-27%) and fertilization (1-14%). Thus, the heavy metals were derived mainly from industrial activities and traffic emissions. For Ni the combined percentage input from irrigation and fertilization was approximately 20% higher than that from atmospheric deposition, indicating that Ni was mainly derived from agricultural activities. Based on isotope ratio analysis, atmospheric deposition accounted for 57-93% of Pb entering soil, with the mean value of 69.3%, which indicates that this was the major source of Pb entering soil in the study area. The mean contributions of irrigation and fertilization to Pb pollution of soil ranged from 0% to 10%, indicating that they played only a marginally important role. Overall, the results obtained using the two methods were similar. This study provides a reliable approach for source apportionment of heavy metals entering agricultural soils in the study area, and clearly have potential application for future studies in other regions.

Human biomonitoring data analysis for metals in an Italian adolescents cohort: An exposome approach

The first Italian human biomonitoring survey (PROBE - PROgramme for Biomonitoring general population Exposure) considered a reference population of adolescents, aged 13-15 years, living in urban and rural areas and investigated their exposure to metals. The study was expanded up to 453 adolescents living in the same areas of Latium Region (Italy) and blood samples were analyzed for 19 metals (As, Be, Cd, Co, Cr, Hg, Ir, Mn, Mo, Ni, Pb, Pd, Pt, Rh, Sb, Sn, Tl, V, and W) by sector field inductively coupled plasma mass spectrometry. The exposure assessment was contextualized following an exposome approach that considered several determinants related to the subjects, available environmental parameters and geo-coding of residence address. To assess the influence of exposure determinants and modifiers on children biomarkers levels we used two independent methodologies. The first makes use of the so-called Environment-Wide Association Study (EWAS) methodology while the second was based on the application of a Generalized Liner Model (GLM) capturing co-exposures to pairs of key determinants. Based on our analysis, Hg and As were positively associated with dietary pathways (primarily linked to fish and to a lesser extent to milk consumption) while Cr showed a more complex interaction between co-exposure to different dietary pathways (milk and fish) coupled to proximity of residence to industrial activities. In addition to diet, socio-economic status of the mother revealed robust statistical associations with Cd, Ni and W biomonitoring levels in the respective children.

Historical documentation of lead toxicity prior to the 20th century in English literature

Lead is a heavy metal that remains a persistent environmental toxin. Although there have been a substantial number of reviews published on the health effects of lead, these reviews have predominantly focused on recent publications and rarely look at older, more historical articles. Old documents on lead can provide useful insight in establishing the historical context of lead usage and its modes of toxicity. The objective of this review is to explore historical understandings and uses of lead prior to the 20th century. One hundred eighty-eight English language articles that were published before the year 1900 were included in this review. Major themes in historical documentation of lead toxicology include lead's use in medical treatments, symptoms of lead poisoning, treatments for lead poisoning, occupational lead poisonings, and lead contamination in food and drinking water. The results of this review indicate that lead's usage was widespread throughout the 19th century, and its toxic properties were well-known. Common symptoms of lead poisoning and suggested treatments were identified during this time period. This review provides important insight into the knowledge and uses of lead before the 20th century and can serve as a resource for researchers looking at the history of lead.