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

Characterization of medium and small-scale gold processing operations, wastewaters, and tailings in the Arequipa region of Peru

Gold cyanidation facilities in the Arequipa Region of Peru are challenged by the availability and quality of water for processing in an arid environment. The facilities reuse decant water which recycles residual cyanide but also undesirable constituents. To understand the impact of intensive water recycling on cyanide and metals concentrations, we collected barren water, decant water, and tailings samples from six gold cyanidation facilities with ore capacities of 10-430 tons per day. Processing facilities in Arequipa recycle all effluents, with decant waters making up 58 ± 11 % of process waters. Decant water contained non-target metals: copper (394 ± 161 mg/L), iron (59 ± 34 mg/L), and zinc (74 ± 42 mg/L). In addition, decant water mean free and complexed cyanide concentrations were 534 ± 129 mg/L and 805 ± 297 mg/L, respectively. Complexed cyanide concentrations remained more constant than free cyanide concentrations with 786 ± 299 mg/L for barren water and 805 ± 297 mg/L for decant water. Cyanide mass balances showed between 21 % and 42 % of unaccounted free cyanide from the start of gold cyanidation and discharge to the tailings storage facility (TSF). Free cyanide estimated losses due to volatilization were 0.8 kg and 2.5 kg of hydrogen cyanide per ton of ore processed at barren water pH of 10.1 and 9.7. Together these results indicate two acute hazards: 1) volatilization of free cyanide during processing and 2) loading and retention of cyanides and metals into TSFs. This study elucidates the extent of uncontrolled vapor phase cyanide release during gold processing operation and contaminant concentrations in the tailings storage facilities. The data highlights the need for improvement oversight, accountability, and regulation of gold processing facilities practicing intensive recycling and zero discharge.

Reference values for metal(loid)s concentrations in the urine samples of healthy Iranian adults: Results from the first nationally representative human biomonitoring study

BACKGROUND

This study measured the concentrations of arsenic (As), aluminum (Al), cadmium (Cd), chromium (Cr), mercury (Hg), nickel (Ni), and lead (Pb) in the urine samples of the Iranian adult population.

METHODS

This nationally representative study was conducted on 490 participants in six provinces of Iran who were selected based on the clustering method. Participants included healthy Iranian adults aged above 25 years without a history of illness and non-smokers. Fasting urine sampling, body composition, and demographic measurements were performed for each participant. Urine samples were analyzed by acid digesting method using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The analysis included descriptive statistics and multiple linear regression using Python programming language.

RESULTS

The geometrical mean (with corresponding reference values, µg/l) concentrations of metal(loid)s in urine for women, men, and both were 198.2 (625.3), 163.5 (486.1), and 192.5(570.4) for Al, 15.6(51.7), 28.8(71.1), and 21.9 (61.64) for As, 18.5(55.2), 20.7(56.5), and 19.22(55.75) for Pb, 17.9(57.6), 17.9 (53.9), and 17.9(56) for Ni, 13.95(47.5), 20.3(62.2) and 16(51.6) for Cr, 3.5(12.2), 2.9(11.5), and 3.3(12) for Hg, 0.74(2.7), 0.95 (3.6), and 0.81(3.1) for Cd. There was a direct relationship between the concentration of metal(loid)s and demographic indicators and body composition (P<0.05). Moreover, there was a direct relationship between the concentration of As, Cr, Hg, Ni, and Pb with age and wealth index (P<0.05).

CONCLUSIONS

The concentrations found could be used as the reference range for As, Al, Cd, Cr, Hg, Ni, and Pb for human biomonitoring studies on the Iranian adult population.

Effect of fertilization on the accumulation and health risk for heavy metals in native Andean potatoes in the highlands of Perú

Soil infertility is a global problem, amendments such as organic fertilizers and mineral fertilizers are used to improve crop yields. However, these fertilizers contain heavy metals as well as essential mineral elements. The objective of the study was to determine the effect of organic and inorganic fertilizer on the accumulation and health risk of heavy metals in tubers. The plants were cultivated at an altitude of 3970 m using four treatments (poultry manure, alpaca manure, island guano and inorganic fertilizer) and a control group. Soil contamination levels and the degree of metal accumulation in the tubers were also determined. As a result, it was found that the use of inorganic fertilizer and poultry manure increased the values of Cu and Zn in soils, exceeding the recommended standards. The accumulation of heavy metals in potato tubers did not exceed the maximum recommended limits with the exception of Pb, which exceeded the limit allowed by the FAO/WHO (0.1 mg kg-1). Poultry manure contributed to the highest accumulation of Zn, Cu and Pb in tubers with 11.62±1.30, 3.48±0.20 and 0.12 ±0.02 mg kg-1 respectively. The transfer of metals from the soil to the tubers was less than 1. Individual and total non-carcinogenic risk values were less than 1, indicating a safe level of consumption for children and adults. The cancer risk was found to be within an acceptable range. However, poultry manure and inorganic fertilizer treatments had the highest total cancer risk values in both age groups, suggesting a long-term carcinogenic risk.

Not All Maca Is Created Equal: A Review of Colors, Nutrition, Phytochemicals, and Clinical Uses

Maca (Lepidium meyenii, Lepidium peruvianum) is part of the Brassicaceae family and grows at high altitudes in the Peruvian Andes mountain range (3500-5000 m). Historically, it has been used as a nutrient-dense food and for its medicinal properties, primarily in enhancing energy and fertility. Scientific research has validated these traditional uses and other clinical applications by elucidating maca's mechanisms of action, nutrition, and phytochemical content. However, research over the last twenty years has identified up to seventeen different colors (phenotypes) of maca. The color, hypocotyl size, growing location, cultivation, and post-harvest processing methods can have a significant effect on the nutrition content, phytochemical profile, and clinical application. Yet, research differentiating the colors of maca and clinical applications remains limited. In this review, research on the nutrition, phytochemicals, and various colors of maca, including black, red, yellow (predominant colors), purple, gray (lesser-known colors), and any combination of colors, including proprietary formulations, will be discussed based on available preclinical and clinical trials. The gaps, deficiencies, and conflicts in the studies will be detailed, along with quality, safety, and efficacy criteria, highlighting the need for future research to specify all these factors of the maca used in publications.

Assessment of the variation of heavy metals and pesticide residues in native and modern potato (Solanum tuberosum L.) cultivars grown at different altitudes in a typical mining region in Peru

This research paper presents the preliminary outcomes of an investigation conducted on the levels of heavy metals (such as As, Cd, Pb, Al, Mn, Cu, Ba, Cr, and Ni) and pesticide residues found in both traditional and modern potato cultivars grown in Moquegua, one of the principal copper-producing departments of Peru. A total of 160 samples of potatoes and soil were collected at altitudes between 58 and 3934 m above sea level (m.a.s.l.), and measured by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES), respectively. Determinations of pesticide residues were conducted by using the QuEChERS method. Metal concentrations in potato samples varied from 0.006 to 0.215 mg/kg for Pb; 0.01-0.25 mg/kg for As; 0.001-0.048 mg/kg for Cd; 0.4-47.9 mg/kg for Al; 0.008-0.802 mg/kg for Cr; 0.505-2.729 mg/kg for Cu; 0.022-29.894 mg/kg for Mn; 0.03-2.76 mg/kg for Ba; to 0.006-0.419 mg/kg for Ni. Among the principal findings of the study were that (i) potatoes grown at lower altitude (Chala and Yunga regions) accumulated more As, Cr, Ni and Al than those grown at higher altitudes (Suni region); (ii) modern potatoes in most cases show a higher concentration of metals than native ones; (iii) the principal positive correlation found between soil and potatoes was for As; (iv) 90% of the samples analyzed were free from pesticide residues.

Human biomonitoring and reference values of urinary 1-hydroxypyrene among Iranian adults population

Polycyclic aromatic hydrocarbons (PAHs) are one of the most important environmental pollutants. Urinary concentrations of 1-hydropyren metabolites of PAHs have been used as biomarkers of these chemicals' exposure in humans. This cross-sectional study was conducted on 468 healthy Iranian adults over 25 years old and non-smokers in six provinces who were selected based on the clustering method. Fasting urine sampling and body composition and demographic measurements were performed. Urine samples were analyzed by GC-MS. The analysis included descriptive statistics and analytical statistics using multiple linear regression by Python software. 1-Hydroxypyrene was found in 100% of samples, and the mean (Reference Value 95%) concentration of 1-hydroxypyrene was 6.12 (RV 95%: 20) μg/L and 5.95 (21) μg/gcrt. There was a direct relationship between the amount of body composition (body fat, visceral fat), BMI, and age with the urinary concentrations of 1-hydropyren metabolites, and this relationship was significant for BMI with urinary concentrations of 1-hydropyren metabolites (P = 0.045). The amount of 1-hydroxypyrene in healthy Iranian adults has been higher than in similar studies in other countries. These results provide helpful information regarding the exposure of Iranian adults to 1-hydroxypyrene, and these data can be used to supplement the national reference values of human biomonitoring for the interpretation of biomonitoring results.

Dataset of metals and metalloids in food crops and soils sampled across the mining region of Moquegua in Peru

In recent years, there has been an increase in interest in the accumulation of heavy metals and metal(loid)s (HMM) in areas where agriculture and mining exist side by side. As a contribution to this body of knowledge, we report the first dataset into HMM concentrations in food crops and agricultural soils in Moquegua, which is a typical mining region and contains one of Peru's largest copper deposits. Thanks to its geographic diversity, samples were taken in different agroecological regions at altitudes between 9 and 3,934 m. For food crops, 31 elements were measured using inductively coupled plasma mass spectrometry and atomic absorption spectrometry. For soils, 23 elements were measured using inductively coupled plasma optical emission spectrometry. Thus, the dataset includes a total of 13,828 observations from 341 sampling sites. We hope that this dataset will facilitate a wide range of agricultural and food safety studies, as well as serving as a reference for monitoring changes in pollution over time or comparing HMM levels with other farmlands influenced by mining activities.

Trace elements in farmland soils and crops, and probabilistic health risk assessment in areas influenced by mining activity in Ecuador

Consumption of food grown in contaminated soils may be a significant human exposure pathway to pollutants, including toxic elements. This study aimed to investigate the pollution level of trace elements in farmland soil and crops collected in orchards from Ponce Enriquez, one of the Ecuador's most important gold mining areas. The concentration of arsenic (As), cadmium (Cd), chrome (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) was analyzed in soil and crop samples (celery, chives, corn, herbs, lettuce, turnips, green beans, cassava, and carrots). In addition, a probabilistic human health risk assessment, in terms of hazard quotients (HQ) and cancer risk (CR), was conducted to assess the potential risk related to local crop ingestion. The contents of As, Cr, Cu, and Ni in soils exceeded the Ecuadorian quality guidelines for agricultural soils. The trace elements concentration in local crops was higher than the maximum permissible levels set by the Food and Agriculture Organization of the United Nations (FAO). The HQ and CR of local crop ingestion were several orders higher than the safe exposure threshold, mainly for lettuce, chives, and turnips. Our results revealed that inhabitants of the study area are exposed to developing carcinogenic and non-carcinogenic effects due to long-term food consumption with high trace elements. This study sheds light on the need to assess further the quality of agricultural soils and crops grown in mining areas with signs of contamination to guarantee consumer food safety.

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.

Ecological Risk Assessment and Source Apportionment of Heavy Metals in the Soil of an Opencast Mine in Xinjiang

To study the influence of open-pit coal mining on the surrounding soil environment and human health, this study selected the Hongshaquan coal mine in Xinjiang as the research area and took 31 soil samples from the dump and artificial forest of the mining area. The contents of seven heavy metals (As, Cd, Cr, Cu, Ni, Pb and Zn) in the soil were analyzed. The pollution index method, geoaccumulation index method (I_geo), potential ecological risk index method, health ecological risk assessment model and principal component analysis (PCA) were used to evaluate and analyze the heavy metal pollution, potential ecological risk and health ecological risk of the soil. The results showed that compared with the background value of soil in Xinjiang, except for Pb, other heavy metal elements were essentially pollution-free and belonged to the low ecological risk area. The health risk assessment model showed that Pb and As were the main pollution factors of noncarcinogenic risk, and that exposure to Ni, Pb and As had a lower carcinogenic risk. The PCA showed that Cu, Cr, Ni, Pb, As and Zn in the dump were from transportation and industrial activities, Cd was from natural resources, and Cr, Zn, Ni, Cd and Pb were from transportation in the artificial forest. Cu came from industrial sources and As from soil parent material. The dump was more seriously disturbed by human factors than by artificial forests. Our research provides a reference for heavy metal pollution and source analysis caused by mining.

Health risk associated with heavy metal contamination of vegetables grown in agricultural soil of Siran valley, Mansehra, Pakistan-a case study

Monitoring of heavy metals in agricultural soils and the crops grown in them is essential to design mitigation strategies to reduce toxic heavy metals in diet and food chains. We determined chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) concentrations in the soil-plant system from agricultural fields of Siran Valley, Mansehra, Pakistan, to assess their potential health risk. Although the concentrations of the heavy metals in soils were within the permissible limits for agricultural soils, heavy metal concentrations in many of the vegetables exceeded the recommended safe values. Among the six leafy vegetables tested, all had greater than safe limits for As, four also for Cr and two also for Cd. As level was greater than safe limits in all five fruit and flower vegetables, two had Cr, and one had Pb also at unsafe levels. Among the five tuber, bulb, and root vegetables, As was higher than safe limits in all and Cd in one. The transfer factor in all three categories of vegetables followed the descending order Cd > As > Cr > Pb. Daily intake of metals were within limit set by USEPA for all heavy metals except As. The health risk indices for Cr, As, Cd, and Pb indicated that values greater than 1 for As suggest that the vegetables studied here pose a risk of chronic arsenic poisoning, but other heavy metals do not pose such a risk. Our study reinforces the need for mitigation strategies to reduce unsafe levels of heavy metals in vegetables.

Effect of home processing methods on the levels of heavy metal contaminants in four food crops grown in and around two mining towns in Ghana

Unregulated small-scale mining activities, by young untrained men using some poisonous chemicals, occur in several agricultural forest belts in Ghana. These activities contaminate water bodies in these areas, which happen to be the main farming sites where food crops are intensively cultivated. The presence of these heavy metal contaminants in popular food staples is therefore worrying because of its adverse health implications. Previous studies have shown that processing is able to decrease the concentrations of heavy metals in foods. This study investigated the effectiveness of home processing methods (boiling, frying and roasting) in significantly reducing the levels of heavy metal contaminants in food crops grown in and around two main mining centers in Ghana. The heavy metals contaminants analyzed for, were Arsenic (As), Cadmium, (Cd), lead (Pb), Manganese (Mn), and Mercury (Hg), determined using atomic absorption spectrometry (AAS) and inductively-coupled plasma mass spectrometry (ICP-MS). From the data, the average daily intakes of the heavy metals and the associated long-term health risks to consumers were assessed. Unprocessed samples from Akwatia had higher levels of contaminants than those from Obuasi. Levels of Mn, Pb and As recorded in all unprocessed samples were higher compared to WHO permissible limits in foods. The levels showed a decreasing trend in the processed samples; with the lowest As and Pb content recorded after frying and boiling. The study showed that roasting allowed for the least reduction in the heavy metal contaminations in the four food crops. The levels of Cd in both processed and unprocessed samples were within safe WHO specifications. Except for Pb in unprocessed cassava, boiled cassava and unprocessed plantain and Hg (unprocessed yam and roasted yam), the hazard indices of all metals in all food crops were less than one and posed no risk to consumers. The study therefore reveals that the normal home processing methods are able to reduce the levels of heavy metal contaminants found in cassava, cocoyam, plantain and yam considerably.