Risk assessment for potentially toxic metal(loid)s in potatoes in the indigenous zinc smelting area of northwestern Guizhou Province, China

Bioaccessibility and bioavailability of essential and potentially toxic trace elements in potato cultivars: A comprehensive nutritional evaluation

Among the most consumed foods in the world is potato, which occupies the first place as a non-grain commodity, demonstrating the importance of its assessment concerning the population's food safety. In this study, the nutrients Ca, Mg, K, P, Cu, Mn, Fe, and Zn and the potentially toxic trace elements Cd, Cr, and Pb were evaluated considering their total contents, bioaccessible and bioavailable fractions in different potato cultivars, in an unpublished approach in the literature. The in vitro standard gastrointestinal digestion method (INFOGEST) and a model of the intestinal epithelial barrier using the Caco-2 cell line were applied for investigate the presence of metals in potato. For the macroelements, the bioaccessibility (% w/w) varied in the ranges: K (57-72 %), P (59-76 %), Mg (83-103 %), and Ca (30-123 %), whereas for the microelements were: Cu (27-74 %) and Mn (4.22-12.02, 60-119 %). The potentially of trace toxic elements, Cd and Pb, were found in 75 % of the samples, however, all the concentration values were below the maximum levels allowed of 0.10 µg/g. Chromium was determined only in potato peels and has no maximum established level. The bioaccessible and bioavailable fractions of Cd, Cr, and Pb were below the limits of quantification of the spectrometric methods (LOQ - µg/L: 0.063 Cd, 0.65 Cr, and 0.44 Pb). The potato samples were considered safe for consumption regarding the presence of potentially toxic trace elements, with a remarkable nutritional contribution.

Distribution characteristics of potentially toxic metal(loid)s in the soil and in tea plant (Camellia sinensis)

Potentially toxic metal(loid) assessment of tea and tea garden soil is a vital guarantee of tea safety and is very necessary. This study analyzed the distribution of seven potentially toxic metal(loid)s in different organs of the tea plants and soil at various depths in the Yangai tea farm of Guiyang City, Guizhou Province, China. Although soil potentially toxic metal(loid) in the study area is safe, there should be attention to the health risks of Cu, Ni, As, and Pb in the later stages of tea garden management. Soil As and Pb are primarily from anthropogenic sources, soil Zn is mainly affected by natural sources and human activities, and soil with other potentially toxic metal(loid) is predominantly from natural sources. Tea plants might be the enrichment of Zn and the exclusion or tolerance of As, Cu, Ni, and Pb. The tea plant has a strong ability for absorbing Cd and preferentially storing it in its roots, stems, and mature leaves. Although the Cd and other potentially toxic metal(loid)s content of tea in Guizhou Province is generally within the range of edible safety, with the increase of tea planting years, it is essential to take corresponding measures to prevent the potential health risks of Cd and other potentially toxic metal(loid)s in tea.

Distribution of nitrate/nitrite and toxic metals in the soil-potato system and its health risk assessment in Iran

Potato is one of the essential food products whose health quality is greatly influenced by soil contamination and properties. In the current study, we have investigated the physicochemical characteristics of agricultural areas and the accumulation of nitrite/nitrate and metals in potato products in Hamedan, Iran. After determining the physicochemical characteristics of soil samples from four agricultural regions of Hamedan, 48 potato samples were collected from these regions. The heavy metals and nitrate/nitrite content were determined by ICP-OES and calorimetric methods, respectively. A negative correlation was observed between soil pH changes with nitrite/nitrate content and the accumulation of some heavy elements in potatoes. Furthermore, a positive correlation was found between soil phosphorus content and lead accumulation in potato. In present study, the amounts of lead, nitrate, and nitrite in 83.3%, 56%, and 12% of the collected samples were higher than the permissible limit reported by the World Health Organization (WHO), respectively. The EDI range for nitrate and nitrite was determined to be 130-260 and 1.4-2.7 µg/kg/day, respectively, which is much lower than the RfD set by the US Environmental Protection Agency (USEPA) for nitrite and nitrate. Among metal pollutants, the toxic risk caused by lead in potato consumers was higher than the threshold limit. In conclusion, our findings showed that the physicochemical characteristics of the soil could effectively increase the availability of metal pollutants and nitrite/nitrate to the potato product and significantly reduce its health quality. Therefore, monitoring these pollutants in the soil-potato system, preventing the entry of industrial wastewater, and managing the use of agricultural fertilizers can effectively improve the health of this product for consumers.

Establishment and Optimization of Soil Cd Risk Threshold in Typical Karst Area with Potato Production, China

The threshold is key to risk assessment of soil cadmium (Cd) pollution. However, there is limited research on the soil Cd risk threshold of potatoes. Soil and potato samples (n = 256) were used to establish and optimize the Cd risk threshold by using relative cumulative frequency, bioconcentration factor, and regression model. The results showed that suggested risk screening values (SRSVs) for soil Cd were divided into 2.465 (pH ≤ 5.5), 2.564 (5.5 < pH ≤ 6.5), 2.778 (6.5 < pH ≤ 7.5), and 4.348 mg kg^-1 (pH > 7.5). SRSVs were applied to classify soil Cd risk assessment by collecting soil samples (n = 100). Low-risk areas only comprised 0.98% of the total area using risk screening values (RSVs) (GB15618-2018), and risk areas comprised as much as 99.02%. Low-risk area and risk area comprised 97.75% and 2.25% of the total area based on SRSVs. SRSVs are appropriate for potato production in typical karst areas.

Soil exposure is the major fluoride exposure pathways for residents from the high-fluoride karst region in Southwest China

In the karst areas of southwest China, soil fluoride levels are higher than in China (478 mg kg^-1) and world (200 mg kg^-1). High levels of F in the environment might pose a health risk to humans. The comprehensive exposure risk must be studied in this area. Herein, samples of crops and soil were collected from Bijie City, a typical karst area in southwest China, to investigate the pollution level and evaluate the comprehensive F exposure risk. The single-factor index (P_Fw) and the geological accumulation index (I_geo) were used. The hazard index (HI) was applied to assess exposure risk from multiple exposure routes. The results revealed that there is considerable F contamination in soil and crops in the study area. Average soil total fluorine (Ft) was 1139.13 mg kg^-1, and soil water soluble F (Fw) was 3.792 mg kg^-1. In corn, rice, wheat, and potatoes, F contents were 1.167-9.585, 1.222-6.698, 1.587-9.976, and 1.797-9.143 mg kg^-1, respectively. The mean values of HI were 4.45 and 2.42 for children and adults, respectively, > 1, showing potential health risk exists. Youngsters are at a greater exposure risk than adults. From the results of contribution ratios of different exposure routes for health risk, the major exposure risk was determined to be from soil exposure. Based on this, we suggest that risk managers mainly strive to control the soil fluoride level and implement the risk education and communication.

The effects of short-term, long-term, and reapplication of biochar on the remediation of heavy metal-contaminated soil

Biochar, a cost-effective amendment, has been reported to play pivotal roles in improving soil fertility and immobilizing soil pollutants due to its well-developed porous structure and tunable functionality. However, the properties of biochar and soils can vary inconsistently after field application. This may affect the remediation of biochar on heavy metal (HM)-contaminated soil being altered. Therefore, we selected lettuce as a model crop to determine the effects of short-term, long-term, and reapplication of biochar on soil physicochemical properties, microbial community, HM bioavailability, and plant toxicity. Our investigation revealed that the long-term application of biochar remarkably improved soil fertility, increased the relative abundance of the phylum Proteobacteria which was highly resistant to HMs, and reduced the abundance of phylum Acidobacteria. These changes in soil properties decreased the accumulation of Cd and Pb in lettuce tissues. The short- and long-term applications of biochar had no substantial effects on biomass, quality, and photosynthesis of lettuce. Moreover, the short-term and reapplication of biochar had no significant effects on soil bacterial communities but decreased the accumulation of Cd and Pb in lettuce tissues. It showed that the changes in the physical, chemical, and biological properties of soil after long-term application of biochar promoted the remediation of HM-contaminated soil. Furthermore, microbial community compositions varied with metal stress and biochar application, while the relative abundance of the phylum Actinobacteria in HM-contaminated soil with long-term biochar application was markedly higher than in HM-contaminated soil without biochar application.

Calcareous Materials Effectively Reduce the Accumulation of Cd in Potatoes in Acidic Cadmium-Contaminated Farmland Soils in Mining Areas

The in situ chemical immobilization method reduces the activity of heavy metals in soil by adding chemical amendments. It is widely used in farmland soil with moderate and mild heavy metal pollution due to its high efficiency and economy. However, the effects of different materials depend heavily on environmental factors such as soil texture, properties, and pollution levels. Under the influence of lead-zinc ore smelting and soil acidification, Cd is enriched and highly activated in the soils of northwestern Guizhou, China. Potato is an important economic crop in this region, and its absorption of Cd depends on the availability of Cd in the soil and the distribution of Cd within the plant. In this study, pot experiments were used to compare the effects of lime (LM), apatite (AP), calcite (CA), sepiolite (SP), bentonite (BN), and biochar (BC) on Cd accumulation in potatoes. The results showed that the application of LM (0.4%), AP (1.4%), and CA (0.4%) had a positive effect on soil pH and cations, and that they effectively reduced the availability of Cd in the soil. In contrast, the application of SP, BN, and BC had no significant effect on the soil properties and Cd availability. LM, AP, and CA treatment strongly reduced Cd accumulation in the potato tubers by controlling the total 'flux' of Cd into the potato plants. In contrast, the application of SP and BN promoted the migration of Cd from the root to the shoot, while the effect of BC varied by potato genotype. Overall, calcareous materials (LM, CA, and AP) were more applicable in the remediation of Cd-contaminated soils in the study area.

Understanding the excretion rates of methylmercury and inorganic mercury from human body via hair and fingernails

Effective biomarkers are necessary to better understand the human mercury (Hg) exposure levels. However, mismatched biomarker sampling method causes extra uncertainty in assessing the risk of Hg exposure. To compare the differences between hair and fingernail, and further understand the excretion rates of methylmercury (MeHg) and inorganic mercury (IHg) via hair and fingernails, the total mercury (THg), MeHg, and IHg concentrations in paired hair and fingernail samples were investigated through paired samples collected from two typical mining areas, Wanshan mercury mine area (WMMA) and Hezhang zinc smelting area (HZSA). The positive correlation in THg, MeHg, and IHg concentrations (p <0.01) between hair and fingernail samples indicated that those two biomarkers can be corrected in application of assessing human Hg exposure. Compared to fingernails, the hair was suggested to be a more sensitive biomarker as the concentration of THg, MeHg and IHg were 2 ∼ 4 times higher than those in fingernails. Furthermore, the amounts of THg, MeHg, and IHg excreted via hair were 70 ∼ 226 times higher than that excreted via fingernails, and the hair plays a more important role than fingernails in the excretion of Hg from human bodies. Present study therefore provides some new insights to better understand the fate of human assimilated Hg.

Co-exposure of potentially toxic elements in wheat grains reveals a probabilistic health risk in Southwestern Guizhou, China

Bijie is located at a typical karst landform of Southwestern Guizhou, which presented high geological background values of potentially toxic elements (PTEs). Recently, whether PTE of wheat in Bijie is harmful to human health has aroused people's concern. To this end, the objectives of this study are to determine the concentrations of PTE [chromium (Cr), nickel (Ni), arsenic (As), lead (Pb), cadmium (Cd), and fluorine (F)] in wheat grains, identify contaminant sources, and evaluate the probabilistic risks to human beings. A total of 149 wheat grain samples collected from Bijie in Guizhou were determined using the inductively coupled plasma mass spectrometer (ICP-MS) and fluoride-ion electrode methods. The mean concentrations of Cr, Ni, As, Cd, Pb, and F were 3.250, 0.684, 0.055, 0.149, 0.039, and 4.539 mg/kg, respectively. All investigated PTEs met the standard limits established by the Food and Agriculture Organization except for Cr. For the source identification, Cr and Pb should be originated from industry activities, while Ni, As, and Cd might come from mixed sources, and F was possibly put down to the high geological background value. The non-carcinogenic and carcinogenic health risks were evaluated by the probabilistic approach (Monte Carlo simulation). The mean hazard quotient (HQ) values in the three populations were lower than the safety limit (1.0) with the exception of As (children: 1.03E+00). However, the mean hazard index (HI) values were all higher than 1.0 and followed the order: children (2.57E+00) > adult females (1.29E+00) > adult males (1.12E+00). In addition, the mean carcinogenic risk (CR) values for Cr, As, Pb, and Cd in three populations were all higher than 1E-06, which cannot be negligible. The mean threshold CR (TCR) values were decreased in the order of children (1.32E-02) > adult females (6.61E-03) > adult males (5.81E-03), respectively, all at unacceptable risk levels. Moreover, sensitivity analysis identified concentration factor (C _W ) as the most crucial parameter that affects human health. These findings highlight that co-exposure of PTE in wheat grains revealed a probabilistic human health risk. Corresponding measures should be undertaken for controlling pollution sources and reducing the risks for the local populace.

Uptake, organ distribution and health risk assessment of potentially toxic elements in crops in abandoned indigenous smelting region

Inorganic pollution induced by smelting waste has threatened the safety of environment, whereas the impacts on farmlands with regards to potentially toxic elements (PTEs) receive insufficient attention. Herein, the contents, transfer pathways and potential risks of the PTEs in common crops were examined from different farmlands distributed around an indigenous Zn-smelting area in Guizhou, China. The results showed that Tl in cabbage (Brassica oleracea L.) (up to 3.74 mg/kg) and radish (Raphanus sativus L.) (up to 1.16 mg/kg) at some sites exceeded the maximum permissible level (MPL) (0.5 mg/kg) for food, and, under the same pollution condition, cabbage and radish were more likely to enrich PTEs, and the edible portion of maize was not prone to Tl risk. Hazard quotient calculations of Tl, Ba, and U were greater than 1, indicating the edible risk of crops for these PTEs. Further characterization of selected soils revealed that MnFe₂O₄ and Fe₂O₃ controlled the phase transformation of Tl(III) in rhizospheric soils. Furthermore, distinctive mullite was detected in the soil which confirmed the contribution of high temperature smelting to PTEs pollution. The findings indicate an emergent need for soil remediation around historical indigenous metal smelting areas for the sake of food security.

Spatial distribution and main controlling factor of cadmium accumulation in agricultural soils in Guizhou, China

A large-scale investigation was conducted on the cadmium (Cd) content in the farmland soils of Guizhou to explore the spatial variation in soil Cd content, identify the main factors responsible for causing Cd pollution, and determine the zonation of Cd pollution. Multivariate statistical analysis, geographic information system (GIS) analysis, and decision tree methods were used to study the distribution, spatial variation, and pollution partitioning of Cd and the factors influencing the Cd accumulation in agricultural soils of the Guizhou province. Areas with high Cd content in agricultural soil were found to be concentrated in the high-altitude areas in the western region of Guizhou province. The results of the single factor pollution index showed that the proportion of sample sites with Cd class I (priority protection), II (security utilization), and III (strict control) in the agricultural soils of Guizhou province were 65.96%, 31.27%, and 2.77%, respectively. In high-altitude areas, the Cd content in the agricultural soils was mainly derived from the soil parent material. In contrast, mining activities and road traffic were the main factors Cd accumulation in agricultural soils in lower altitude areas.

Distribution characteristics and potential pollution assessment of heavy metals (Cd, Pb, Zn) in reservoir sediments from a historical artisanal zinc smelting area in Southwest China

Reservoir sediment contamination with heavy metals produced by mining activities has aroused widespread global concern owing to its potential threat to human health. In this study, the total concentrations and speciation of heavy metals (Cd, Pb, Zn) in the Lexi (LX) and Maoshui (MS) reservoirs around the historical artisanal zinc smelting area in Southwest China were determined, and pollution indices were applied to assess the pollution levels and potential ecological risks of the two reservoirs. The results showed that all the detected samples in the two reservoirs presented significant metal accumulation, especially for Cd, as compared with the soil background values in Guizhou Province. Between the two reservoirs, the vertical distribution characteristics of each metal in sediment columns were similar. The heavy metal concentrations of the three columns in the LX reservoir reached their maxima at 35, 15, and 10 cm and showed a trend of first increasing and then decreasing overall. However, the heavy metal contents of the three columns in the MS reservoir all exhibited wave-like characteristics in the vertical direction, and all of them reached a relatively obvious high point at approximately 5 and 30 cm. The geoaccumulation index (I_geo) and potential ecological risk index (RI) indicated that Cd was strongly enriched and represented the main risk factor, and the pollution level of the MS reservoir was significantly higher than that of the LX reservoir. Furthermore, the effect coefficients (ERMQ) confirmed that the two reservoirs are likely to have toxic impacts on aquatic organisms and need to be controlled and mitigated. The speciation analysis of heavy metals revealed that Cd was primarily in the acid-extractable fraction (69.57%, 68.28%), Pb was chiefly in the reducible fraction (55.24%, 42.18%) and oxidizable fraction (22.60%, 38.02%), and Zn was mainly in the oxidizable fraction (32.54%, 37.65%) in the LX and MS reservoirs, respectively. The ratios of the secondary phase and primary phase (RSP) and risk assessment code (RAC) evaluation demonstrated that Cd in the sediments of the two reservoirs presents a very high potential ecological risk, and Pb and Zn were at medium to high ecological risk levels. This study highlighted that the artisanal zinc smelting activities had caused serious heavy metal pollution in reservoir sediments, posing a threat to the local ecological environment.

Distribution and dispersion of heavy metals in the rock-soil-moss system of the black shale areas in the southeast of Guizhou Province, China

Black shales are easily exposed due to human activities such as mining, road construction, and shale gas development, which results in several environmental issues including heavy metal (HM) pollution, soil erosion, and the destruction of vegetation. Mosses are widely used to monitor metal pollution in the atmosphere, but few studies on the distribution and dispersion of HMs in the rock-soil-moss system are available. Here, mosses (Pohlia flexuosa Harv. in Hook), growing soils, and corresponding parent rocks were collected from black shale areas. After appropriate pretreatment, samples were analyzed for multiple elemental concentrations by ICP-AES and ICP-MS. The results show that black shale parent rocks have elevated HM concentration and act as a source of multiple metals. The overlying soil significantly inherits and accumulates heavy metals released from black shale. Significant positive correlations between HMs in P. flexuosa and the growing soils indicate that HMs are mainly originating from geological source rather than atmospheric deposition. Differential accumulation of HMs is observed between rhizoids and stems in our study. Moreover, P. flexuosa is able to cope with high concentrations of toxic metals without any visible negative effect on its growth and development. Finally, the bioconcentration factor (BCF) for all the HMs in P. flexuosa is less than 1, indicating that it has a tolerance and exclusion mechanism for these metals, especially for the non-essential elements As and Pb. Therefore, the luxuriant and spontaneous growth of P. flexuosa could be used as a phytostabilization pioneer plant in the black shale outcrop where vascular plants are rare.

Heavy metals accumulation and risk assessment in a soil-maize (Zea mays L.) system around a zinc-smelting area in southwest China

Smelting of nonferrous metals causes significant concerns because of its emissions of heavy metals (HMs) into surface soil, and its potential threat to human health through the food chain. To investigate the HMs concentrations in a soil-maize system, a total of 41 paired soil-maize samples were collected from a typical indigenous zinc-smelting area of northwestern Guizhou Province, China. Results showed that the concentrations of the targeted HMs in the soil were significantly higher than their corresponding background values of Guizhou Province. Results obtained of the geo-accumulation index (I_geo) and the potential ecological risk factor of an individual metal (E _r ⁱ ) revealed that Cd and Pb were identified as the top-priority control HMs in the study area. The mean concentrations in maize grain decreased in the order of Zn > Pb > Cu > Cd. Bio-accumulation factor (BAF) indicated a strong ability for Cd to be accumulated in the maize root. Translocation factor (TF) and Fourier transform infrared (FTIR) spectroscopy revealed that the maize root played an important role in reducing the mobilization of HMs to stem, except for Zn. Kriging interpolation results illustrated that the spatial distribution patterns of HMs in the maize grain were generally similar to those in sampled soil, and the higher concentrations for the investigated HMs were partially overlapping between soil and maize grain. The average hazard quotient (HQ) of the investigated HMs for both children and adults were all lower than the threshold value (HQ = 1). The total hazard index (HI) was 5.51E-01 and 4.24E-01 for the two population groups, respectively, implying no potential non-carcinogenic risk for local maize-consumers. Sensitivity analysis demonstrated that the oral ingestion rate (IngR) of grain was the predominated contribution to the output of the risk assessment.

New Insights into Selenium Enrichment in the Soil of Northwestern Guizhou, Southwest China

Selenium (Se) is an essential trace element for animals and plants. Se in soil has an important influence on the Se intake by animals and plants. To explore the source of Se in soils of the zinc-smelting area in northwest Guizhou, China, 271 topsoils and 50 deep soil samples were collected, and the concentration, speciation and distribution of Se in soils were analysed. The results showed that the concentration of Se in topsoils ranged from 0.2 mg/kg to 1.79 mg/kg, with an average of 0.84 mg/kg, which was more than 2 times of that in deep soil. These observations indicated that Se was enriched in the surface layer of soil. In terms of spatial distribution, high-Se topsoils (> 1.0 mg/kg) were mainly distributed near the zinc smelting area, and topsoil samples with relatively low content of Se were mainly distributed in areas with less human activities influence. The Se occurrence species in topsoils were in the order of residue, organic-binding, humic-acid binding, water-soluble, Fe/Mn/Al oxide-binding, carbonate-binding and ion-exchange. The contribution of residual Se to total Se in topsoil was decisive, and the content of other species of selenium changed slightly. The Se speciation that was residual in soil is difficult for plants to utilize, which is consistent with previous studies on seleniferous soils caused by zinc smelting. These results indicated that the main reason for Se enrichment in the topsoils of northwest Guizhou Province was indigenous zinc smelting.

Steel mill waste application in soil: dynamics of potentially toxic elements in rice and health risk perspectives

Potentially toxic elements (PTEs) are of great concern in steel mill wastes. Therefore, in order to use them as potential fertilizers in soil, risk assessments are needed. Three steel mill wastes were tested as possible amendments for soils at seven different doses (0, 0.5, 1, 2, 4, 8, 16 t ha^-1): phosphate mud (PM), metallurgical press residue (MPR), and filter press mud (FPM) during rice cultivation in a pot experiment in a Haplic Gleisol. Analysis on rice tissues, including roots, shoots, husk, and grains, were conducted and contents of Cu, Cd, Ni, Zn, Mn, and Pb were assessed. Translocation and bioaccumulation factors were calculated for each element. In general, PTEs are more accumulated in roots and greater contents of Zn and Mn were found, while the lowest ones were found for Pb, probably due to its lack of functional roles during plants development. Higher translocation was observed for Mn, which is associated to the redox conditions of rice cultivation and the high mobility of this element under this condition. Application of steel mill wastes can increase PTE bioavailability and translocation factors, especially PM, but all of the wastes reveal a high hazard index.

Heavy metals in soils and edible tissues of Lepidium meyenii (maca) and health risk assessment in areas influenced by mining activity in the Central region of Peru

Heavy metal contamination of soil and agricultural products is an environmental problem, has an adverse effect on the quality of food crops, and is a danger to food security and public health. The concentration of arsenic (As), cadmium (Cd), lead (Pb), iron (Fe) and zinc (Zn) in surface soils and edible hypocotyls tissues of two ecotypes of Lepidium meyenii Walpers (maca) was evaluated in three districts of the Junín province, Peru. In addition, the risk to human health due to exposure to heavy metals from maca consumption was evaluated. Soil samples and maca hypocotyls were collected in areas influenced by mining and metallurgical activity. The mean concentration of Cd (0.32 ± 0.23 mg/kg) and Pb (0.20 ± 0.12 mg/kg) in maca samples exceeded the values established by the Food and Agriculture Organization and the World Health Organization. The bioconcentration factor was less than 1. The estimated daily intake of each metal was below the oral reference dose. The hazard quotient and hazard index were less than 1, it is unlikely to cause non-cancer adverse health outcome. The cancer risk for As and Cd was higher than the tolerable limit (1 × 10-6) in children and adults. In the district of Ondores, the cancer risk for As in children was higher than the acceptable limit (1 × 10-4). Residents of the Ondores district would be more exposed to As and Cd from consumption of maca hypocotyls. It is very important to carry out continuous monitoring of other toxic metals in different ecotypes of maca (red, black, yellow, purple, creamy white, pink) in order to evaluate the variation in the accumulation of heavy metals and the level of toxicity of each metal between ecotypes.

Occurrence of Chemical Contaminants in Peruvian Produce: A Food-Safety Perspective

The presence of chemical contaminants in agricultural products is a continued food-safety challenge in Peru. This country has robust agriculture potential, but its output of fruits and vegetables is severely impacted by massive mining activities, as well as poor farming practices, including the use of polluted irrigation water, misuse of pesticides, and inadequate postharvest conditions. This review examines the current scientific knowledge on the levels of pesticide residues, heavy metals, and mycotoxins on crops produced in Peru. The available data shows that several crop varieties are contaminated with these classes of chemical contaminants, and at levels that exceed the national and international permissible limits. The abundance of chemical contaminants in produce indicates a relevant food-safety issue, which increases the risks of chronic human diseases, like cancer—a leading cause of death in Peru. Finally, this review presents recommendations to address these contamination problems in produce grown in the Andean country.

Potentially toxic metal(loid) distribution and migration in the bottom weathering profile of indigenous zinc smelting slag pile in clastic rock region

BACKGROUND

There are contaminated by potentially toxic metal(loid)s (PTMs) that the surface soil and the weathering profiles around the indigenous zinc smelting slag piles or smelters in the smelting area. However, few systematic studies are currently focusing on the PTM distribution and migration among the slag and its bottom weathering profile.

METHODS

This research determined the concentrations of PTMs and pH values. And we analyzed PTM distribution in the two weathering profiles (slag-covered and slag-absent) with a small horizontal distance in the clastic rock region in the smelting area.

RESULTS

The soil As and Pb contents, respectively, within the 30 and 50 cm depth in the slag-covered section were higher than those in the slag-absent profile. All soil Cd and Zn contents of the slag-covered core were significantly higher than those in the slag-absent weathering section.

CONCLUSIONS

Compared with the slag-absent weathering section, some PTMs (i.e., As, Cd, Pb and Zn) in the bottom weathering profile were polluted by these elements in the covered slag in the clastic rock region, and their depths were influenced by the slag to varying degrees. Additionally, with time, some PTMs (especially Cd and Zn) of the slag might finally contaminate the groundwater by leaching and infiltration through its bottom weathering profile in the clastic rock region.

Risk Assessment for Oral Bioaccessibility of Lead and Cadmium in the Potato Growing in Smelter-Impacted Soil

Smelting activities are an important source of heavy metals in soil. More seriously, oral ingestion of crops growing in contaminated soil potentially cause harmful effects on human health. The main purpose of this study is to apply the in vitro model (PBET) and Monte Carlo Simulation (MSC) to the health risk assessment process in order to more accurately and realistically evaluate health risks of residents eating contaminated potato. Results indicated in the raw and cooked potato, the bioaccessibility of Pb was 65.9% and 74.5%, and that of Cd was 79.6% and 61.7%, respectively. Additionally, the bioaccessible hazard quotient (BHQ) was less than the permitted level except for the BHQ of Pb for children. This indicated there wasn't potential non-carcinogenic risk for most potato-consumers but the dietary exposure risk for local children cannot be neglected. Sensitivity analysis showed that the bioaccessibility and ingestion rate appeared decisive with respect to potentially deleterious health effects.

Heavy Metal(loid)s Contamination in Ground Dust and Associated Health Risks at a Former Indigenous Zinc Smelting Area

Indigenous zinc smelting (IZS) is a backward technique that releases a great deal of heavy metal(loid)s into the environment. However, the contamination of heavy metal(loid)s in ground dust and the associated health risks in such areas are poorly known. In this study, a former IZS area in Guizhou, China, was surveyed during 2008–2018 with 15 elements (Ag, As, Bi, Cd, Co, Cr, Cu, Hg, In, Ni, Pb, Sb, Sn, Tl, Zn) being analyzed. The results indicate that most elements (e.g., Ag, As, Cd, Cu, Pb, Sb, Sn, Zn) in ground dust decreased significantly after the cessation of the IZS in 2006; nevertheless, some elements still remained at relatively high levels in 2018, e.g., Pb (average: 762 ± 647 mg/kg), Zn (average: 1287 ± 753 mg/kg), Cd (average: 7.76 ± 5.06 mg/kg), and As (average: 41.9 ± 34.8 mg/kg), indicating they might come from the local contaminated soils, slag residues and smelting potteries. In terms of the impacts on human health, children have both higher non-carcinogenic and carcinogenic risks than that of adults, with the latter subpopulation having a lower risk than the threshold values. Pb and As were the two elements with the highest non-carcinogenic risk for children, the hazard index of local children was still higher than the threshold of 1 (e.g., 1.43 for As, 2.09 for Pb) in 2018. The carcinogenic risk of As exposure to children dropped more than two times to 6.42 × 10⁻⁷ in 2018, which falls below the tolerable range (10⁻⁶–10⁻⁴). This study revealed that although the concentration of heavy metal(loid)s in ground dust and linked health risk in the IZS area has reduced dramatically after the cessation of IZS, continued removal of slag residues and smelting potteries is necessary for further decreasing the human health risk.

Cohort profile: China National Human Biomonitoring (CNHBM)-A nationally representative, prospective cohort in Chinese population

OBJECTIVE

Globally, developed countries such as the United States, Canada, Germany, Korea, have carried out long-term and systematic biomonitoring programs for environmental chemicals in their populations. The China National Human Biomonitoring (CNHBM) was to document the extent of human exposure to a wide array of environmental chemicals, to understand exposure profiles, magnitude and ongoing trends in exposure in the general Chinese population, and to establish a national biorepository.

METHODS

CNHBM adopted three-stage sampling method to obtain a nationally representative sample of the population. A total of 21,888 participants who were permanent residents in 31 provinces were designed to interviewed in this national biomonitoring (152 monitoring sites × 3 survey units × 2 sexes × 6 age groups × 4 persons = 21,888 persons) in 2017-2018. Unlike the US National Health and Nutrition Examination Survey, the CNHBM will follow the same participants in subsequent cycles allowing for dynamic, longitudinal data sets for epidemiologic follow-up. Each survey cycle of CNHBM will last 2 years and each subsequent cycle will occur 3 years after the prior cycle's completion.

RESULTS

In 2017-2018, the CNHBM created a large cohort of Chinese citizens that included districts/counties questionnaire, community questionnaire collecting information on villages/communities, individual questionnaire, household questionnaire, comprehensive medical examination, and collection of blood and urine samples for measurement of clinical and exposure biomarkers. A total of 21,746 participants were finally included in CNHBM, accounting for 99.4% of the designed sample size; and 152 PSUs questionnaires, 454 community questionnaires, 21,619 family questionnaires, 21,712 cases of medical examinations, 21,700 individual questionnaires, 21,701 blood samples and 21,704 urine samples were collected, respectively. Planned analyses of blood and urine samples were to measure both inorganic and organic chemicals, including 13 heavy metals and metalloids, 18 poly- and per-fluorinated alkyl substances, 12 phthalate metabolites, 9 polycyclic aromatic hydrocarbons metabolites, 4 environmental alkylated phenols, and 2 benzene metabolites.

CONCLUSIONS

CNHBM established the first nationally representative, prospective cohort in the Chinese population to understand the baseline and trend of internal exposure of environmental chemicals in general population, and to understand environmental toxicity.

Legacy of multiple heavy metal(loid)s contamination and ecological risks in farmland soils from a historical artisanal zinc smelting area

Farmland soil contamination of heavy metal(loid)s (HM) derived from smelting activities is a global concern, owing to its potential threat for human health through food chain. This study aims to evaluate total contents and bioavailability of HMs (Pb, Zn, Tl, Cd, Cu, As, Ag, Co, Cr and Ni) in farmland soils distributed over ten different villages from a former artisanal zinc smelting area in the northwest Guizhou province, China. The results showed that most of the studied soils still exhibited exceptionally high enrichment of Pb, Zn, Cd and As. High levels of bioavailable HMs were also observed in some samples, which may enter the human food chain through agricultural activities. Further analyses by Scanning Transmission Electron Microscopy - Energy Dispersive Spectroscopy (STEM-EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) showed the presence of Zn smelting by-products such as Fe oxides, ZnO and PbSO₄ even in nanoscale particles retained by the soils. Elemental mapping by EDS confirmed a close association of the studied HMs with the smelting waste particles. All these results signify that high levels of HM-contamination from historical artisanal zinc smelting activities still persist and threaten the health of local residents, despite the fact that the major industrial-derived-contamination period ended >15 years ago. Our findings highlight pivotal concerns in similar artisanal-smelting-affected farmland soils of suspected contamination, due to less-expected toxic elements such as Tl, which may cause high ecological health risks.

Platinum and Rhodium in Potato Samples by Using Voltammetric Techniques

Potato is a starchy, tuberous crop from the perennial Solanum tuberosum having high nutritional values. This paper is the first analytical approach to quantify Pt and Rh in vegetal food. In this study a total of 38 different potato samples produced in Europe and one in Australia were investigated. Determinations of Pt and Rh in potato samples were carried out by Differential pulse voltammetry (DPV/a) for platinum and by Adsorptive stripping voltammetry (AdSV) for Rh using standard addition procedure. Because no certified reference potatoes containing platinum and rhodium are available, we used addition standard method. The quantification limits for Pt and Rh are 0.007 and 0.0008 μg kg⁻¹ respectively. Considering all the potato samples, concentrations of Pt and Rh vary in the ranges from 0.007 to 109 μg kg⁻¹ (sample no, 6 potatoes grown in Sicily) and from 0.0008 to 0.030 μg kg⁻¹ (sample no. 3 of potatoes grown in Emilia Romagna), respectively. For both metals, in many cases the concentrations fall near the quantification limit. In all the samples, platinum is always more abundant than rhodium and their mean ratio is 14,500, which is much greater than that of the Earth’s crust (about 100).