Heavy Metal Accumulation in Fruits and Vegetables and Human Health Risk Assessment: Findings From Maharashtra, India

Development of RT-LAMP assay for detection of lead and cadmium toxicity using HepG2 cells

Heavy metals such as lead and cadmium are prevalent in the environment. These are harmful to living beings even at lower concentrations as they persist in the body for years and lead to the development of severe diseases. Therefore, the present work was designed to develop a rapid and field-applicable cell-based assay for quick detection of lead and cadmium in biofluids using an RNA biomarker. The RNA biomarker was identified by analyzing the impact of these heavy metals on the gene expression of candidate genes using HepG2 cells. The results showed that the gene expression of AhR pathway-related genes, apoptosis-related genes, MAPK1, and HMOX1 were significantly increased after lead and cadmium treatments (P < 0.05). Interestingly, the gene expression of HMOX1 was increased linearly up to fivefold in a dose and time-dependent manner in the case of both heavy metals which also correlated with an increased secretion of bilirubin from the cells after 6 h treatment. Therefore, the RT-LAMP assay was developed for lead and cadmium toxicity using HMOX1. The positive amplification was visualized in the form of color change of HNB dye from violet to blue in 30 min. Additionally, standard curves were also prepared for the RT-LAMP color change after treatment with different concentrations of lead and cadmium for their quantification in unknown samples. The developed RT-LAMP assay was also validated using lead and cadmium-spiked milk samples. The ROC curve analysis showed 100% sensitivity and specificity for both heavy metals above their MRL value in infant milk substitutes and infant foods. This assay can be utilized for early detection of heavy metals in common food items such as milk.

Do Crops Grown at Urban Dumpsites Contain Metals at Levels that Pose Unacceptable Health Risks to Consumers?

Excessive dietary metal intake from crops grown on contaminated urban dumpsites poses a global health risk to consumers. We evaluated the health risk to adult and child consumers from dietary exposure to metals and metalloids in crops cultivated at the Mbale (Uganda) dumpsite centre. Thirteen crop types grown on the dumpsite soil were sampled and analyzed for concentrations of 11 metals: Fe, Al, Zn, Mn, Cu, Pb, Cr, Hg, Co, Ni, Cd, and two metalloids: Se and As. Different proportions of the crops were combined into 12 meal classes to simulate the diets of residents and estimate noncancer and cancer risks. The findings indicated that most individual crop types and simulated diets lacked sufficient selenium for bodily functions. Furthermore, their metal accumulations exceeded the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) permissible limits (mg/kg) for Al (20), Fe (100), Ni (10), Cu (20), Mn (10), Pb (0.3), Se (0.05), and Zn (99.4). The four most abundant metals in the various crop types and diets were Al, Fe, Mn, and Zn. A positive correlation between the metals in the crops indicated a common origin, which could possibly be the dumpsite soil. The chronic dietary intake (CDI) of metals was higher in children, and thus children faced higher noncancer and cancer risks compared with adults. The overall CDI values for each metal ranged from 0.000718 to 2.171 in adults, and 0.00125 to 3.781662 in children, which is approximately 1.74 times higher in children than in adult consumers. The noncancer and cancer risks ranged from moderate to high with Co, Cr, Fe, Mn, and Zn being mostly responsible for the high noncancer risks, and Al being the predominant contributor to cancer risks. The total noncancer risk levels equally ranged from moderate (1.4-3.3) for adults, and moderate to high (2.4-5.7) for children; the cancer risks were moderate to high in adults, with Al contributing to between 68% and 92% of the total risks across the 12 meal classes. Overall, CDI values and noncancer and cancer risks were all higher in children than in adults. The vegetables Amaranthus hybridus, Vigna unguiculate, Amaranthus dubius, and Cucurbita maxima significantly contributed to the high noncancer risk to both adults and children, particularly when they constituted 40% or more of the meal. Four additional vegetables (Cocorhrous olitorous, Brassica oleracea, Amaranthus cruentus, and Gynandropsis gynandra) also posed a high risk to children when consumed in large quantities. Our results highlight the urgent need to develop regulatory frameworks and/or rigorously enforce existing land and food governance policies to protect consumers' health from unsafe metal concentrations in crops grown on dumpsites. Environ Toxicol Chem 2024;43:2628-2644. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Health-risk assessment of mercury in main market-sold foods in the Pingliang region of Gansu province, China, from 2013 to 2021

In the present study, we analyzed mercury concentrations in 742 samples across five main food categories from 2013 to 2021 using direct mercury analysis (DMA) to understand mercury pollution in major market-sold foods in the Pingliang region of Gansu Province and assess the health risks of mercury dietary exposure in adults. Health risks of adult dietary exposure were assessed through deterministic evaluation. Total mercury content ranged from non-detectable (ND) to 0.13 mg/kg, with a detection rate of 90.70% (673/742), the highest detection rates being in fresh edible mushrooms and nuts. The overall exceedance rate was 0.13% (1/742), with one sample of fresh edible mushrooms exceeding the regulatory limit for total mercury content. Additionally, we incorporated the average mercury content and consumption levels of meat and seafood from regions geographically close to Pingliang, as reported in the Fifth National Total Diet Study, to calculate the Estimated Daily Intake (EDI) by a deterministic evaluation. For adult males, the exposure was 0.120 μg/(kg BW), while for adult females, it was 0.141 μg/(kg BW). Both values are significantly lower than the provisional tolerable weekly intake (PTWI) of 4 μg/(kg BW) established by JECFA in 2010, indicating that the total mercury concentration from food intake does not pose a significant health risk to the residents of the Pingliang area. These findings offer valuable scientific data to inform food safety regulations in the region and can serve as a benchmark for future mercury pollution risk assessments in other locations.

Determination of trace elements content of fruits from Tehran's market using ICP- OES method: a risk assessment study

For the first time in Iran, in this study, the amount of 19 trace elements in some types of commonly consumed Iranian fruits (in their peel and pulp) was evaluated by ICP-OES (Inductively coupled plasma-optical emission spectrometry) method. Based on the outcomes, the highest and lowest average detected elements in all fruits samples were related to (Al) aluminum (1842.18) and (V) vanadium (0.28) ppm, respectively. Mercury (Hg) and antimony (Sb) were not detected (ND) in any samples. Also, the maximum mean of elements in quince, lemon, grapefruit, kiwi, orange south, orange north and tangerine samples was related to(Fe) iron (2048.32 ppm), (Zn)zinc(753.45 ppm), Fe (1056.33 ppm), Al (9794.41 ppm), Zn (717.78 ppm), Fe (1334.87 ppm) and Fe (974.93 ppm), respectively. Furthermore, our outcomes revealed, the highest mean of elements in kiwi peel, kiwi pulp, orange North peel, orange North pulp, orange South peel, orange South pulp, quince peel, quince pulp, grapefruit peel, grapefruit pulp, lemon peel, lemon pulp, tangerine peel and tangerine pulp was related to Al (17967.79 ppm), Al (1621.03 ppm), Fe (1350.01 ppm), Al (1457.66 ppm), Zn (934.71 ppm), Fe (728.06 ppm), Fe (2768.11 ppm), Fe (1328.54 ppm), Zn (1008.54 ppm), Fe (1198.00 ppm), Zn (683.35 ppm), Zn (823.55 ppm), Fe (1182.59 ppm), and Fe (767.27 ppm), respectively. Based on the Monte Carlo simulation results, the THQ (target hazard quotient) and ILCR (Incremental Lifetime Cancer Risk) related to exposure to heavy metals via fruits for adults and children showed that there is no significant non-carcinogenic risk (THQ < 1) and carcinogenic risk (ILCR < 1E-4) for adults and children.

Health risks of metals in soils and staple foods of the subsistence food gardens in the floodplains of Watut River, Papua New Guinea

The health risks associated with the consumption of staples cultivated in the subsistence food gardens along the Watut River were investigated in Papua New Guinea. Twenty soil samples and twenty-nine samples of staple foods (including banana, taro, sweet potato, and Singapore taro) were collected from the food gardens following a three-day dietary recall survey. The concentration of metals (Cr, Cu, Pb, and Ni) was analyzed in the soil and food samples using Inductively Coupled Plasma Optical Emission Spectrophotometer. The descending order of mean metal concentration in the food garden soils is as follows: Cr > Cu > Ni > Pb. The concentration of Pb in all samples and Cr in 97% of staple foods exceeded the FAO/WHO permissible limits. Approximately 87% of adult consumers of bananas (Musa sp) were found to have estimated Cr and Pb ingestion levels exceeding the permissible daily tolerable intake of metals (0.2 and 0.21 mg day-1, respectively). Hazard index values from the staples analysis indicate that the consumption of bananas (9.40) poses the highest risk of non-carcinogenic effects on adults, followed by taro (7.32), sweet potato (6.13), and Singapore taro (4.30). The consumption of taro is dangerous due to cancer risk associated with the intake of excessive Ni (2.88E-02) and Cr (8.82E-03) in adults and children compared to banana, sweet potato, and Singapore taro. Non-carcinogenic hazards of metal ingestion were found to be pronounced in the younger population, while carcinogenic effects were more serious in adults. Urgent measures must be implemented to protect communities, especially children, from the dangerous effects of heavy metal ingestion through staples in the lower Watut region.

A View on the Chemical and Biological Attributes of Five Edible Fruits after Finishing Their Shelf Life: Studies on Caco-2 Cells

We studied five common perishable fruits in terms of their polyphenols dynamic, minerals distribution, scavenger activity and the effects of 50% ethanolic extracts on the viability of Caco-2 cells in vitro, over a period of time between T = 0 and T = 5/7 days, typically the end of their shelf life. Altogether, there were few changes found, consisting of either an increase or a decrease in their chemical and biological attributes. A slow decrease was found in the antioxidant activity in apricot (-11%), plum (-6%) and strawberry (-4%) extracts, while cherry and green seedless table grape extracts gained 7% and 2% antioxidant potency, respectively; IC50 values ranged from 1.67 to 5.93 μg GAE/μL test extract. The cytotoxicity MTS assay at 24 h revealed the ability of all 50% ethanol fruit extracts to inhibit the Caco-2 cell viability; the inhibitory effects ranged from 49% to 83% and were measured at 28 µg GAE for strawberry extracts/EES, from 22 µg to 45 µg GAE for cherry extracts/EEC, from 7.58 to 15.16 µg GAE for apricot extracts/EEA, from 12.50 to 25.70 µg GAE for plum extracts/EEP and from 21.51 to 28.68 µg GAE for green table grape extracts/EEG. The MTS anti-proliferative assay (72 h) also revealed a stimulatory potency upon the Caco-2 viability, from 34% (EEA, EEG) and 48% (EEC) to 350% (EES) and 690% (EEP); therefore fruit juices can influence intestinal tumorigenesis in humans.

Mercury air, urine monitoring and health effects on occupationally exposed dental healthcare workers in Delhi, India

BACKGROUND

Mercury (Hg) is a toxic heavy metal with multiple uses in various medical devices. Hg is used in dentistry as a restorative material. Such use creates significant exposure to dental practitioners. Hence, it is important to assess the risk created by Hg use in healthcare.

OBJECTIVE

To quantify airborne Hg vapour exposure and Hg levels in dental healthcare workers, and determine the association of various symptoms and diseases to Hg exposure.

METHODS

Air monitoring of Hg vapours were conducted in dental clinics and amalgam rooms. Urine samples were collected from occupationally exposed dental healthcare workers and urine Hg levels were measured. A cross-sectional health survey was conducted in 23 healthcare units of Delhi to determine an association between Hg exposure and various health effects.

RESULTS

Hg vapour concentration ranged from 0.96μg/m3 to 15μg/m3, the highest concentration was recorded in the amalgam room (15μg/m3). Urine Hg levels in healthcare workers (0.51±0.17μg/L) were higher than the control (0.29±0.05μg/L). A cross-sectional health survey revealed a significant prevalence of confusion, forgetfulness, muscle spasm, and tremors by the respondents.

CONCLUSION

Hg concentration in dental clinics may hover above the prescribed safe levels posing a definitive health risk to healthcare workers. Urinary Hg measurements did not reveal an excess of body burden except in one case. Since Hg bio accumulates, it is probable as these workers grow older, they may end up with a higher body burden of Hg that may lead to a variety of adverse health outcomes.

Effects of Mars Global Simulant (MGS-1) on Growth and Physiology of Sweet Potato: A Space Model Plant

Growing food autonomously on Mars is challenging due to the Martian soil's low nutrient content and high salinity. Understanding how plants adapt and evaluating their nutritional attributes are pivotal for sustained Mars missions. This research delves into the regeneration, stress tolerance, and dietary metrics of sweet potato (Ipomoea batatas) across different Mars Global Simulant (MGS-1) concentrations (0, 25, 50, and 75%). In our greenhouse experiment, 75% MGS-1 concentration significantly inhibited sweet potato growth, storage root biomass, and chlorophyll content. This concentration also elevated the plant tissues' H2O2, proline, and ascorbic acid levels. Higher MGS-1 exposures (50 and 75%) notably boosted the vital amino acids and sugar groups in the plant's storage roots. However, increased MGS-1 concentrations notably diminished the total C:N ratio and elemental composition in both the vines and storage roots. In summary, sweet potato exhibited optimal growth, antioxidant properties, yield, and nutrient profiles at 25% MGS-1 exposure as compared to higher concentrations. This study underscores the need for future interventions, like nutrient enhancements and controlled metal accessibility, to render sweet potato a suitable plant for space-based studies.

Möbius carbon nanobelts interacting with heavy metal nanoclusters

CONTEXT

The interaction between carbon nanostructures and heavy metal clusters is of great interest due to their potential applications as sensors and filters to remove the former from environment. In this work, we investigated the interaction between two types of carbon nanobelts (Möbius-type nanobelt and simple nanobelt) and nickel, cadmium, and lead nanoclusters. Our aim was to determine how both systems interact which would shed light on the potential applications of the carbon nanostructures as pollutant removal and detecting devices.

METHODS

To investigate the interaction between carbon nanostructures and heavy metal nanoclusters, we utilized the semiempirical tight binding framework provided by xTB software with the GFN2-xTB Hamiltonian. We performed calculations to determine the best interaction site, lowest energy geometries, complexes stability (using molecular dynamics at 298K), binding energy, and electronic properties. We also carried out a topological study to investigate the nature and intensity of the bonds formed between the metal nanoclusters and the nanobelts. Our results demonstrate that heavy metal nanoclusters have a favorable binding affinity towards both nanobelts, with the Möbius-type nanobelt having a stronger interaction. Additionally, our calculations reveal that the nickel nanocluster has the lowest binding energy, displaying the greatest charge transfer with the nanobelts, which was nearly twice that of the cadmium and lead nanoclusters. Our combined results lead to the conclusion that the nickel nanoclusters are chemisorbed, whereas cadmium and lead nanoclusters are physisorbed in both nanobelts. These findings have significant implications for the development of sensor and filtering devices based on carbon and heavy metal nanoclusters.

Plants, animals, and fisheries waste-mediated bioremediation of contaminants of environmental and emerging concern (CEECs)-a circular bioresource utilization approach

The release of contaminants of environmental concern including heavy metals and metalloids, and contaminants of emerging concern including organic micropollutants from processing industries, pharmaceuticals, personal care, and anthropogenic sources, is a growing threat worldwide. Mitigating inorganic and organic contaminants, which can be coined as contaminants of environmental and emerging concern (CEECs), is a big challenge as traditional physicochemical processes are not economically viable for managing mixed contaminants of low concentrations. As a result, low-cost materials must be designed to provide high CEEC removal efficiency. One of the environmentally viable and energy-efficient approaches is biosorption, which involves using biomass or biopolymers isolated from plants or animals to decontaminate heavy metals in contaminated environments using inherent biological mechanisms. Among chemical constituents in plant biomass, cellulose, lignin, hemicellulose, proteins, polysaccharides, phenolic compounds, and animal biomass include polysaccharides and other compounds to bind heavy metals covalently and non-covalently. These functional groups include carboxyl, hydroxyl, carbonyl, amide, amine, and sulfhydryl. Cation-exchange capacities of these bioadsorbents can be improved by applying chemical modifications. The relevance of chemical constituents and bioactives in biosorbents derived from agricultural production such as food and fodder crops, bioenergy and cash crops, fruit and vegetable crops, medicinal and aromatic plants, plantation trees, aquatic and terrestrial weeds, and animal production such as dairy, goatery, poultry, duckery, and fisheries is highlighted in this comprehensive review for sequestering and bioremediation of CEECs, including as many as ten different heavy metals and metalloids co-contaminated with other organic micropollutants in circular bioresource utilization and one-health concepts.

The Expression of the StNRAMP2 Gene Determined the Accumulation of Cadmium in Different Tissues of Potato

Cadmium (Cd) is a toxic metal that threatens human health when enriched in crops. NRAMPs are a family of natural macrophage proteins reported to play a key role in Cd transport in plants. In order to explore the gene regulation mechanism of potato under Cd stress and the role of NRAMPs family in it, this study analyzed the gene expression differences of two different Cd accumulation levels in potato after 7 days of 50 mg/kg Cd stress and screened out the key genes that may play a major role in the differential accumulation of Cd in different varieties. Additionally, StNRAMP2 was selected for verification. Further verification showed that the StNRAMP2 gene plays an important role in the accumulation of Cd in potato. Interestingly, silencing StNRAMP2 increased Cd accumulation in tubers but significantly decreased Cd accumulation in other sites, suggesting a critical role of StNRAMP2 in Cd uptake and transport in potatoes. To further confirm this conclusion, we performed heterologous expression experiments in which overexpression of StNRAMP2 gene in tomato resulted in a threefold increase in Cd content, which further confirmed the important role of StNRAMP2 in the process of Cd accumulation compared with wild-type plants. In addition, we found that the addition of Cd to the soil increased the activity of the plant antioxidant enzyme system, and silencing StNRAMP2 partially reversed this effect. This suggests that the StNRAMP2 gene plays an important role in plant stress tolerance, and future studies could further explore the role of this gene in other environmental stresses. In conclusion, the results of this study improve the understanding of the mechanism of Cd accumulation in potato and provide experimental basis for remediation of Cd pollution.

Growing of the Cretan Therapeutic Herb Origanum Dictamnus in The Urban Fabric: The Effect of Substrate and Cultivation Site on Plant Growth and Potential Toxic Element Accumulation

Origanum dictamnus L. (Lamiaceae) is a perennial herb endemic to the Greek island of Crete, widely used for tea preparation, medicinal purposes, and food flavoring, as well as an ornamental plant. The aim of this work was to introduce the species to the green roof sector while serving urban agriculture. Thus, its growth potential was investigated, along with the content of nutrients (N, P, K, Na) and the accumulation of heavy metals (Cu, Pb, Ni, Mn, Zn, Fe) in its tissues, in two cultivation sites in Athens, Greece, i.e., an extensive green roof and at ground level next to a moderate traffic road. Cultivation took place in plastic containers with a green roof infrastructure fitted, in two substrate types (grape marc compost, perlite, and pumice 3:3:4 v/v, and grape marc compost, perlite, pumice, and soil 3:3:2:2 v/v), with 10 cm depth. Plant growth was favored by the soil substrate, but it was also satisfactory in the soilless one. Cultivation site affected heavy metal accumulation, resulting in higher concentrations both in leaves and in flowers at street level, while no differences were observed in roots. Washing the tissues reduced heavy metal concentrations only in leaves produced at the street level. Substrate type significantly affected Mn concentration in all plant tissues and Fe in roots, with the highest values measured in the soil substrate. Thus, O. dictamnus could be effectively cultivated in sustainable green roofs, better on a soilless substrate to lower construction weight. Careful selection of the cultivation site could minimize contamination with environmental pollutants if human consumption is also desired.

Deterministic and Probabilistic Health Risk Assessment of Toxic Metals in the Daily Diets of Residents in Industrial Regions of Northern Ningxia, China

This study was designed to investigate the toxic metal (aluminum (Al), arsenic (As), chromium (Cr), cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn)) concentrations in drinking water and different foodstuffs meat (pork, beef, and mutton), cereals (rice, flour, corn, millet), beans (cowpeas, tofu), potatoes (potato, sweet potato), solanaceous fruits (pepper, eggplant, bitter gourd, cucumber), vegetables (cabbage, cauliflower, spinach), and fruits (apples, watermelons, pears, grapes)) and then estimate the potential health risks of toxic metal consumption to local residents in industrial regions of northern Ningxia, China. As in drinking water, Cr in meat, Pb in cereals, Pb in beans, As and Pb in potatoes, Pb in solanaceous fruits, Cr and Ni in vegetables, and Ni and Pb in fruits were the most contaminated heavy metals in the corresponding food with over-standard rates of 16.7%, 12.5%, 5.1%, 60%, 50%, 50%, 38.2%, 44.4%, 44.4%, 31.8%, and 31.8%, respectively.The results of the deterministic assessment of health risks showed that the total noncarcinogenic risk value of dietary intake of toxic metals by the local population was 5.6106, indicating that toxic metals pose a high noncarcinogenic risk. The order of the non-carcinogenic risk is HI_cereal (1.2104) > HI_{solanaceous fruit} (0.9134) > HI_Vegetables (0.8726) > HI_Fruit (0.8170) > HI_Meat (0.7269) > HI_{Drinking water} (0.6139) > HI_Beans (0.2991) > HI_Potatoes (0.1573). The total carcinogenic health risk from exposure to toxic metals through dietary intake was 9.98 × 10^-4, indicating that the total cancer risk value of residents is beyond the acceptable range (10^-4) under the current daily dietary exposure and implies a high risk of cancer. The order of the carcinogenic risk is R_{Drinking water} (2.34 × 10^-4) > R_Meat (2.11 × 10^-4) > R_{solanaceous fruit} (1.89 × 10^-4) > R_Fruit (1.88 × 10^-4) > R_cereal (1.36 × 10^-4) > R_Potatoes (2.44 × 10^-5) > R_Vegetables (1.51 × 10^-5) > R_Beans (0). The probabilistic assessment results showed that 98.83% of the population is exposed to severe noncarcinogenic risk and 87.02% is exposed to unacceptable carcinogenic risk. The sensitivity analysis showed that drinking water, local cereals, vegetables, and fruits were the major contributors to health risks. Our results indicated that the daily dietary exposure of residents in industrial regions of northern Ningxia poses a serious threat to human health, and it is suggested that relevant departments should strengthen monitoring and control of the current situation of toxic metal pollution in the environment and continue to pay attention and take measures to reduce the exposure of toxic metals in the diets of residents in this area.

Human Health Risk Assessment due to Heavy Metals in Ground and Surface Water and Association of Diseases With Drinking Water Sources: A Study From Maharashtra, India

BACKGROUND

Contamination of freshwater sources can be caused by both anthropogenic and natural processes. According to Central Pollution Control Board, Maharashtra along with 2 other states, contribute 80% of hazardous waste generated in India, including heavy metal pollution. Hence, it is important to quantify heavy metal concentrations in drinking water sources in such areas.

MATERIALS AND METHODS

Water samples were analyzed for toxic elements (F, As, Cd, Hg, Pb, Ni, Cu, Zn, Mn, and Cr) using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) Agilent 7500. Health risks due to ingestion and dermal contact was assessed. A total of 557 people were randomly selected, with consumers from all 4 types of water sources that is surface water, hand pump, wells, and municipal water. Spot urine samples were collected from 47 people after considering inclusion and exclusion criteria. Urine was collected for estimating mercury and arsenic levels in the study participants.

RESULTS

Arsenic contributes the most health risk from ingestion from water. Among surface water users, 14 people (32%) reported frequent loose stool (P-value < .05) (OR 2.5), and 11 people (23%) reported frequent abdominal pain (OR 1.9). Hand pump and well water users reported frequent abdominal pain (27%) (OR 1.4) and gastric discomfort (31%) (P-value < .05) (OR 3) respectively. The mean value of urinary Hg and As were 4.91 ± 0.280 and 42.04 ± 2.635 µg/L respectively.

CONCLUSION

Frequent loose stool, gastric discomfort, and frequent abdominal pain were associated with the various sources of drinking water. Urine Hg levels were found higher than the NHANES (USA) Survey. It is recommended that frequent monitoring of drinking water should be enforced around the industrial hub, so that appropriate actions can be taken if present in excess.