Public health risk assessment associated with heavy metal and arsenic exposure near an abandoned mine (Kirki, Greece)

Hazardous enrichment of toxic elements in soils and olives in the urban zone of Lavrio, Greece, a legacy, millennia-old silver/lead mining area and related health risk assessment

Lavrio is a Greek town with several abandoned Ag/Pb mines. In this study, 19 potentially toxic elements (PTEs) were measured in soil, weeds, and olives. Levels of seven of the studied PTEs in soil were highly elevated: Zn (56.2-58,726 mg kg^-1), Pb (36.2-31,332), As (7.3-10,886), Cu (8.3-1273), Sb (0.99-297.8), Cd (0.17-287.7), and Ag (0.09-38.7). Synchrotron-based X-ray absorption near edge structure analysis of the soils revealed that As was predominantly associated with scorodite, Pb with humic substances, Zn with illite, Zn(OH)₂ and humic substances, and Fe with goethite-like minerals. The transfer of the PTEs to weeds was relatively low, with the transfer coefficient being less than 1.0 for all PTEs. Cadmium in table olives surpassed 0.05 mg kg^-1 fresh weight (the limit in EU), while Pb surpassed its limit in approximately half of the samples. Health risk assessment confirmed soil contamination in the study area where As and Pb hazard quotients were well above 1.0 and the average hazard index equaled 11.40. Additionally, the cancer risk values exceeding the 1 × 10^-4 threshold. The results obtained in the study indicate that Lavrio urgently requires an adequate ecofriendly remediation plan, including revegetation with tolerant species and targeted efforts to chemically stabilize harmful PTEs. The presented approach may serve as a pivotal study for industrial areas with similar contamination levels.

Arsenic concentrations, distributions and bioaccessibilities at a UNESCO World Heritage Site (Devon Great Consols, Cornwall and West Devon Mining Landscape)

Devon Great Consols (DGC) is a region in south west England where extensive mining for Cu, Sn and As took place in the nineteenth century. Because of its historical and geological significance, DGC has protected status and is part of the Cornwall and West Devon Mining Landscape UNESCO World Heritage Site. Recently, the region was opened up to the public with the construction or redevelopment of various trails, tracks and facilities for walking, cycling and field visits. We used portable x-ray fluorescence spectrometry to measure, in situ, the concentrations of As in soils and dusts in areas that are accessible to the public. Concentrations ranged from about 140 to 75,000 μg g^-1 (n = 98), and in all but one case exceeded a Category 4 Screening Level for park-type soil of 179 μg g^-1. Samples returned to the laboratory and fractionated to <63 μm were subjected to an in vitro assessment of both oral and inhalable bioaccessibility, with concentrations ranging from <10 to 25,500 μg g^-1 and dependent on the precise nature and origin of the sample and the physiological fluid applied. Concentrations of As in PM₁₀ collected along various transects of the region averaged over 30 ng m^-3 compared with a typical concentration in UK air of <1 ng m^-3. Calculations using default EPA and CLEA estimates and that factor in for bioaccessibility suggest a 6-h visit to the region results in exposure to As well in excess of that of minimum risk. The overall risk is exacerbated for frequent visitors to the region and for workers employed at the site. Based on our observations, we recommend that the remodelling or repurposing of historical mine sites require more stringent management and mitigation measures.

Probabilistic human health risk assessment of arsenic under uncertainty in drinking water sources in Jiangsu Province, China

Concentrations of arsenic (As) in 65 drinking water sources in Jiangsu Province of China were analyzed from January 2013 to December 2015. The drinking water sources are classified into five water systems of the Yangze River, the Taihu Lake, the Huai River, the Yishusi River, and other lakes or reservoirs, which are termed as WS-A, WS-B, WS-C, WS-D, and WS-E, respectively. Health risk assessments associated with As in terms of total carcinogenic risk and total hazard index were performed for children (0-5 years), teenagers (6-17 years), and adults (≥ 18 years), respectively. Probabilistic risk assessments were obtained by applying Monte Carlo approach with consideration of uncertainty. The results indicated that in drinking water sources of WS-A, WS-C, and WS-D, maximum concentrations of As were 28 μg/L, 40 μg/L, and 17 μg/L, respectively, which were higher than 10 μg/L recommended by the World Health Organization occurred. Based on the samples investigated in this study, the mean health risks are the highest in drinking water source WS-D and lowest in WS-E for both male and female children, teenagers, and adults. For drinking water source WS-A, the health risks of male children, male teenagers, and female adults are higher than female children and female teenagers, and male adults. However, for drinking water sources WS-B, WS-C, WS-D, and WS-E, the health risks of female children, male teenagers, and female adults are higher than male children, female teenagers, and male adults. The highest health risks occurred in female children consuming drinking water from WS-D. The sensitivity analysis indicated that the concentration of As is the primary factor for carcinogenic risk of all the five water systems. The results obtained can provide meaningful information for risk managers in Jiangsu Province.

Using human epidemiological analyses to support the assessment of the impacts of coal mining on health

The potential impacts of coal mining on health have been addressed by the application of impact assessment methodologies that use the results of qualitative and quantitative analyses to support their conclusions and recommendations. Although human epidemiological analyses can provide the most relevant measures of risk of health outcomes in populations exposed to coal mining by-products, this kind of studies are seldom implemented as part of the impact assessment methods. To review the use of human epidemiological analyses in the methods used to assess the impacts of coal mining, a systematic search in the peer review literature was implemented following the PRISMA protocol. A synthesis analysis identified the methods and the measures used in the selected publications to develop a thematic review and discussion. The major methodological approaches to assess the impacts of coal mining are environmental impact assessment (EIA), health impact assessment (HIA), social impact assessment (SIA) and environmental health impact assessment (EHIA). The measures used to assess the impacts of coal mining on health were classified as the estimates from non-human-based studies such as health risk assessment (HRA) and the measures of risk from human epidemiological analyses. The inclusion of human epidemiological estimates of the populations exposed, especially the general populations in the vicinity of the mining activities, is seldom found in impact assessment applications for coal mining. These methods rather incorporate HRA measures or other sources of evidence such as qualitative analyses and surveys. The implementation of impact assessment methods without estimates of the risk of health outcomes relevant to the potentially exposed populations affects their reliability to address the environmental and health impacts of coal mining. This is particularly important for EIA applications because these are incorporated in regulatory frameworks globally. The effective characterization of the impacts of coal mining on health requires quantitative estimates of the risk, including the risk measures from epidemiological analyses of relevant human health data.

Cadmium contamination in a soil-rice system and the associated health risk: An addressing concern caused by barium mining

Cadmium (Cd) is associated with barite; however, its biogeochemical characteristics in environments impacted by barium (Ba) mining are not known. Here, we first revealed the characteristics of Cd concentrations, distributions, and chemical forms in the soil-rice system in Ba mining areas. The associated exposure and risk assessments of Cd via rice consumption were also conducted. Elevated levels of Cd with a wide range of 0.054-91 mg/kg were found in paddy soils, approximately 63% of which exceeded the national Grade II value for soil Cd levels in China (0.3 mg/kg). A significant positive correlation between the soil Cd and soil Ba demonstrated that large amounts of Cd were released into the environment from Ba mining. Cadmium accumulated remarkably in the rice grains (0.007-3.5 mg/kg). The chemical forms in the rice plants indicated that most of the Cd was in the pectate/protein fraction (F2, 92% in the grains and 61-71% in the other tissues), followed by the residual fraction (F3, 7.1% in the grains, 27-38% in the other tissues). A minor portion of Cd was in the soluble and aminophenol fraction (F1, 0.44% in the grains, 0.26-1.4% in the other tissues). The positive correlations observed between the grain Cd and F2 in the roots, stems and leaves suggested that Cd in the rice grain was mainly from F2. Similarly, the root F2 was also positively correlated with that in the stems/leaves, indicating the critical role of F2 in Cd²⁺ migration in rice tissues. The estimated average hazard quotient (2.5) and annual excess lifetime cancer risk (21 × 10^-5 a^-1) were higher than the safety levels of 1 and 5.0 × 10^-5 a^-1, respectively, showing that the dietary intake of Cd via rice consumption posed high health risks to residents. Our study demonstrated that more concerns should be paid to Cd contamination in Ba mining areas.

A critical prospective analysis of the potential toxicity of trace element regulation limits in soils worldwide: Are they protective concerning health risk assessment? - A review

Trace elements (TEs) may have toxic effects to plants and humans; thus, countries and organizations impose maximum allowable regulation limits of their concentrations in soils. Usually such limits are placed in different categories according to soil use, soil properties or based on both attributes. However, some countries have regulation limits irrespective of differentiation in soil properties. In this review, we aimed at collecting TE regulation limits in soils from major countries and organizations around the globe, and critiquing them by assessing potential human health risks in the case of soils attaining the maximum allowable values. We explored the soil-to-human pathway and differentiated among three major exposures from TEs, i.e., residential, industrial and agricultural. We observed the existence of problems concerning TE regulation limits, among which the fact that limits across countries do not regulate the same TEs, not even a minimum number of TEs. This indicates that countries do not seem to agree on which regulation limits of TEs pose a high risk. Also, these regulation limits do not take into account TE mobility to neighbouring environment interphases such as plant, especially edible, and water matrices. Moreover, limits for same TEs are vastly diverse across countries; this indicates that those countries have conflicting information concerning TE-related health risks. Subsequently, we addressed this problem of diversity by quantifying resultant risks; we did that by calculating human health risk indices, taking into consideration the cases in which the highest allowable TE limits are attained in soil. Arsenic limits were found to generate a relatively high hazard quotient (HQ_i, accounting for human intake over the maximum allowable oral reference dose for that same TE), indicating that its risk tends to be underestimated. Other TE limits, such as those of Cd, Cu, Ni, Pb, and Zn typically result in low HQ_i, meaning that limits in their cases are rather overprotective. Our approach reveals the need of reducing diversity in regulation limits by drafting soil legislations of worldwide validity, since risks are common across countries. We suggest that new directions should strategically tend to (a) reduce limits of TEs with underestimated contribution to health risk (such as As), (b) cautiously increase limits of TEs that currently cause minor health risks, (c) quantify TE risks associated with uptake to edible plants and potable water, and (d) consider multi-element contamination cases, where risks are cumulatively enhanced due to TE synergism.

Soil and maize contamination by trace elements and associated health risk assessment in the industrial area of Volos, Greece

Agricultural lands adjacent to industrial activities are vulnerable due to the risk of trace elements (TEs) being accumulated into crops and subsequently humans. One such case concerns the industrial area of Volos, Greece, a suspected contaminated area which has never been studied. We measured Ag, Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Sn, Tl, V, and Zn in soil and maize (leaves and grains) and assessed health risk of human exposure via soil ingestion and grain consumption. We found that the most highly enriched elements in soils were Tl (enrichment factor = 19), Se (17.68), Sb (14.81), As (7.89), Ni (6.91), Mo (5.22) and Cr (4.33); they all likely derived from anthropogenic activities and in particular from a nearby major steel factory, except for Ni which is known to be lithogenically elevated in that area. Synchrotron XANES spectra analysis revealed that As species were associated with ferrihydrite, and predominant species were As(V) (at ca. 85%) and As(III) (at ca. 15%). Although the total content of the studied elements was high, the ammonium bicarbonate-DTPA extractions recovered very low element concentrations, probably due to the fact that soil conditions decelerated solubility (i.e., soils were alkaline, clayey, and with high Fe oxides content). This was confirmed by the soil-to-grain transfer index, which was particularly low for all studied elements. In 5% of sampled grains concerning Cd, and in 40% concerning Pb, the European food-related regulation limits were surpassed. Health risk assessment showed a dramatically elevated risk for Tl via soil ingestion (hazard quotient, HQ = 2.399), a value that contributed 74% of the total risk. Similarly, concerning the grain consumption-related health risk, Tl was the predominant contributor (HQ = 0.128, contributing 40% of the total risk). Such elevated Tl risk which has rarely been reported previously, led to a considerably high hazard index (HI) well above the threshold of HI = 1. Cancer risk was below the 1 × 10^-4 risk threshold for As and Pb. Our findings indicate that this study should be pivotal concerning similar industrially-affected agricultural soils of suspected contamination, since less-expected toxic elements such as Tl here may be primary contributors to health risk.

Different exposure profile of heavy metal and health risk between residents near a Pb-Zn mine and a Mn mine in Huayuan county, South China

Heavy metal contamination of environmental media in mining area is a global major concern because of its potential threat for human health through food chain. However, the comparison of exposure level and health risk is scarce among people living in the vicinity of mining area with different pollution source. In this study, the concentrations of Mn, Cd, As, Pb, Cu, Zn, Cr and Ni in soil, air, water, rice, vegetable, fish, poultry meat and pork from a Pb-Zn mining area and a Mn mining area in Huayuan county, China were determined by inductively coupled plasma mass spectrometry. Results showed that the environmental media and foodstuffs in the two areas were contaminated by Cd, Pb, Zn, Cu, Cr and Ni. However, the pollution was more serious in Pb-Zn mining area than Mn mining area. The total hazard index (HI) was 6.59 and 4.55 in Pb-Zn mining area and Mn mining area, respectively, indicating a moderate non-carcinogenic risk of local people. As intake via rice ingestion was the predominant contributor to the total HI in the two mining areas, accounting for 25% and 35%, respectively. For Pb-Zn mining area, Cd intake through vegetable consumption and Mn intake via air inhalation appeared to be another two important components contributing to HI. This study highlights the multi-element and multi-pathway exposure assessment to evaluate the potential health risk and emphasizes concerns to reduce As and Cd in agricultural products as well as Mn in air to decrease the detrimental health effects of local resident.

The Levels and Potential Carcinogenic Risks of PAHs in Liaohe Estuarine Reed Wetland Soils

Sixteen polycyclic aromatic hydrocarbons (PAHs) were quantified by GC/MS in 30 soil samples of Liaohe estuarine reed wetland. The total concentrations of 16 PAHs ranged from 235 to 374 ng g^-1, and seven carcinogenic PAHs concentrations were in the range of 83-109 ng g^-1. A probabilistic carcinogenic potential for three age groups (including children, teenagers, and adults) exposed to soil PAHs via three pathways was quantitatively calculated based on Monte Carlo simulations. The 95th percentiles carcinogenic risks of PAHs for children, teenagers, and adults were 7.80 × 10^-8, 4.03 × 10^-8, and 1.14 × 10^-7, respectively. The carcinogenic risk levels were all below 10^-6, indicating no potential for cancer development. Dermal contact and accident ingestion of soil were the dominant exposure pathways to soil PAHs. BaP and DBahA were the major contributors to carcinogenic risk in this study. Sensitivity analysis demonstrated that exposure duration and PAH concentrations in soil were the key exposure parameters in calculating carcinogenic risk. Results from this study will provide valuable information for potential scientific evaluation and prevention for carcinogenic risk exposed to soil PAHs.