Metal Concentrations In Vegetables Research Articles

Assessment of Some Heavy Metals in Selected Vegetables, Fruits and their Respective Soil

The concentration of selected heavy metals such as Cr, Ni, Mn, Fe, Mg, Cu and Pb in vegetables ( Colocasia esculanta and Abelmoschus esculentus ) and fruits ( Psidium guajava and Pyrus ) was assessed using atomic absorption spectrophotometer. The concentrations of heavy metals in vegetables and fruits were found in the range of 0.225 to 1.918 mg/L for Cr, 0.367 to 0.794 mg/L for Ni, 0.678 to 7.226 mg/L for Mn, 5.557 to 24.12 mg/L for Fe, 30.02 to 175.4 mg/L for Mg, 0.137 to 1.072 mg/L for Cu and 0.334 to 1.408 mg/L for Pb. Level of Cr was found higher in Colocasia esculanta and lowest in Pyrus (1.110- and 0.225 mg/L respectively). The highest level of Ni was found in Pyrus while lowest was in Soil of Abelmoschus esculentus (0.794 and 0.340 mg/L respectively). The highest level of Mn was observed in Soil of Colocasia esculanta while lowest in Abelmoschus esculentus vegetable (7.226 and 0.678 mg/L resoectively). Maximum level was found in Soil of Psidium guajava while minimum in Colocasia esculanta vegetable (24.07 and 5.557 mg/L. Maximum concentration appeared in Soil sample of Colocasia esculanta while minimum in Psidium guajava fruit (175.4 and 14.73 mg/L). Abelmoschus esculentus showed highest level of Cu while minimum level was found in Colocasia esculanta (1.072 and 0.137mg/L). Pb showed maximum amount in Psidium guajava and minimum in soil of Abelmoschus esculentus (1.408 and 0.334 mg/L). The values of Cr, Ni, Mn, Fe, Mg, Cu and Pb in all samples are in the safe limit. However the study indicates that the vegetables, fruits and soil samples are contaminated by toxic heavy metals. .

Monitoring and modeling of heavy metal contents in vegetables collected from markets in Imo State, Nigeria.

Vegetable consumption is one major exposure route of heavy metals to humans, but few data exist for Imo State, Nigeria. We assessed the contamination levels and associated health risk of cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) in vegetables (Telfairia occidentalis, Pterocarpus mildbraedii, Gongronenina latifolium and Vernonia amygdalina) that are consumed frequently from markets (n=16) in three zones of Imo State, Nigeria. After wet-digestion of samples, the supernatant were analyzed using atomic absorption spectrophotometry. The mean concentrations in the four vegetables ranged from 0.006±0.003 mg/kg to 0.011±0.007 mg/kg for Cd, 0.064±0.012 mg/kg to 1.225±0.226 mg/kg for Co, 10.711±1.968 mg/kg to 25.088±13.975 mg/kg for Cu, 0.062±0.013 mg/kg to 0.307±0.210 mg/kg for Ni, 0.006±0.005 mg/kg to 0.012±0.002 mg/kg for Pb and 63.55±4.055 mg/kg to 104.126±24.080 mg/kg for Zn. Except for Zn, all heavy metals in the various vegetables were below the joint standard of Food and Agriculture Organization and World Health Organization. Although, overall load of heavy metal was very low, Zn had the highest contamination factor in vegetables. Heavy metals concentrations in vegetables generally showed low to high variations and statistically different (p<0.05). Average daily intake was below the provisional tolerance limit except for Zn. The target hazard quotient of metals in vegetables for both children and adults were below 1, indicating no potential risk to the public. Overall, heavy metals hazard index were below 1, indicating acceptable level of non-carcinogenic adverse health effect. However, potential multi-element contamination from ingestion is possible as revealed by the correlation profiling of heavy metals.

A comparative study of metals concentration in agricultural soil and vegetables irrigated by wastewater and tube well water

This study was aimed to evaluate the metals concentration in agricultural soil and vegetables irrigated by different irrigation sources. For this purpose agricultural soil and eight vegetables used for commercial consumption were collected from waste-water and tube-well water irrigated sites of Lahore district. Metals i.e. iron (Fe), sodium (Na), potassium (K), magnesium (Mg) and calcium (Ca) were analyzed via flame atomic absorption spectrophotometer. Concentration of metals in soil and vegetables irrigated by wastewater was higher considerably as compared to the soil and vegetables irrigated by tube well water. Among heavy metals concentration in vegetables irrigated by waste-water, trend was appeared as K > Na > Ca > Mg > Fe, while vegetables cultivated by tube-well water, trend was appeared as K > Ca > Na > Mg > Fe. Similarly, leafy vegetables accumulated higher heavy metals levels as compared to non-leafy vegetables.

Uptake of nutrients and heavy metals in struvite recovered from a mixed wastewater of human urine and municipal sewage by two vegetables in calcareous soil

Struvite (MAP) recovered from a mixed wastewater of human urine and municipal sewage through a novel two-step precipitation method was well developed, but its nutrient availability and pollutant transmission to plants have not been investigated. The objective of this study is to explore the feasibility of using MAP as a phosphorus (P) fertilizer in cultivating vegetables by comparing with single superphosphate (SSP). A greenhouse pot experiment was conducted with two P rates (0 vs 0.4 g P2O5/pot) and two vegetables of cabbage and lettuce were planted in the calcareous soil. The vegetable biomass and chemical concentrations of nitrogen (N), P, and metal elements in the soil and vegetable tissues were determined. Results showed that MAP and SSP supply greatly increased the cabbage biomass compared with the unfertilized control because the supply of SSP/MAP enhanced the P, Mg, and K accumulation in the cabbage shoots. However, P fertilization decreased the lettuce biomass, especially MAP application, because the high soil pH and external P fertilization together hampered Zn uptake by the lettuce. The heavy metal concentrations in vegetables supplied by MAP were lower than the maximal contaminant levels for Chinese food safety national standard (GB2762-2017). Based on these findings, it was concluded that MAP is a promising P fertilizer for cultivating cabbage in the tested soil. However, the vegetable should be carefully considered in further studies when MAP is used as a P fertilizer in calcareous soils.

Heavy Metal Contamination of Irrigation Water, Soil, and Vegetables and the Difference between Dry and Wet Seasons Near a Multi-Industry Zone in Bangladesh

Heavy metal (Cr, Cu, Zn, As, Cd, and Pb) contamination in irrigation water, soil, and vegetables was investigated in farmland adjacent to a multi-industry zone in Bangladesh in dry and wet seasons. In the zone, many factories release wastewater into nearby irrigation canals, and vegetables cultivated with this water could be a major food chain route for human exposure. In the irrigation water and vegetables, heavy metal concentrations exceeded permissible levels in the two seasons, but this was not the case in soil. Zn had the highest concentration, and Cd had the lowest concentration in irrigation water, soil, and vegetables. All heavy metal concentrations were found to be lower in the wet than in the dry season, which is due to the dilution of water by rainfall, lower absorption of heavy metals from the diluted irrigation water, and heavy metal absorption from low concentrated irrigation water and/or soil. The cluster analysis data of irrigation water, soil, and vegetables revealed that the heavy metals in vegetables were considered to be absorbed from irrigation water in the wet season and from soil in the dry season. In the dry season, the high heavy metal concentrations in vegetables might be caused by a high bioconcentration factor (mostly &gt; 20%).

Heavy metal concentration in fluted pumpkin and earthworm from roadside and dumpsite farms in Port Harcourt City, Nigeria.

The study investigates heavy metal concentrations in vegetables, earthworms and dumpsite farms in Port Harcourt city. Samples were collected from the road sides, dump sites and control sites. Metals investigated were cadmium, nickel, copper, zinc and lead. These were analyzed using Atomic AbsorptionSpectrophotometer (AAS). The earthworm collected from road side have highest concentrations of zinc, nickel and copper. The road side vegetables have the highest lead concentration with Mean±SD value of 70.362±37.523 mg/kg followed by dump site with Mean±SD value of 10.937±4.781 mg/kg, p&lt;0.05. Lead was not detected in the earthworm samples from the three sampling locations. The dumpsite earthworms have the highest concentration of cadmium with Mean values of 8.326±1.02 mg/kg, p&lt;0.01 followed by road side with Mean±SD value of 7.436±1.242 mg/kg, p&lt;0.05. Cadmium was not detected in soil samples from the three locations. The leafy vegetables contained the highest values of most heavy metals especially those collected from the road side farm and the dumpsite farm. All the soil samples from the three locations were below DPR target value. Continuous monitoring is highly essential.

Concentrations of heavy metals in vegetables between 2004 and 2018, and its impacts on human health in China

Heavy metals in vegetables are of great concern worldwide due to their potential bioaccumulation in human. This review-based study researched the concentrations of heavy metals in vegetables from all provinces of China between 2004 and 2018, and assessed the health risk for the residents. The results displayed the highest Pb, Cd, Cu, and Zn concentrations in vegetables were 0.192 mg/kg (west area), 0.071 mg/kg (central area), 3.961 mg/kg (central area), and 10.545 mg/kg (central area), which were lower than the maximum allowable concentration. In the national scale, the weighted average level of heavy metals in vegetables was found to be in the order of Zn > Cu > Pb > Cd. The hazard index (HI) of each province showed that beside Anhui and Hunan province, residents in other provinces of China faced a low high risk of Pb, Cd, Cu, and Zn. However, people consuming vegetables faced a high risk of Pb, Cd, Cu, and Zn in Anhui and Hunan provinces. This research may provide insight into heavy metal accumulation in vegetables and forecast to residents to cope with these problems for improved human health.

Heavy metal accumulation in vegetable species and health risk assessment in Serbia.

Continuous monitoring of heavy metal content in vegetables is of high priority for population nutrition control, as well as risk assessment for human health. The chemical composition of plants is a reliable indicator of their contamination by hazardous substances accumulated in the environment as a consequence of inadequately applied agro-technology. The main goal of this study was to examine the quality of vegetables that reach consumer markets as a function of growth location. Samples of 11 of the most common vegetable species used in the human diet were collected during a 4-year survey. Vegetables originated from local farm producers who cultivated them at different locations in Vojvodina Province, Serbia. Many vegetable samples contained disturbingly high levels of the investigated metals: cadmium, lead, nickel, and chromium. The plant species with the highest Cd accumulation was spinach, where Cd leaves exceeded the maximum permissible concentrations (MPCs) in more than half of the analyzed samples from different localities (54%). Pb concentrations in spinach were also higher than MPC values (according to Serbian law 3.0μg/g) in 46% of all analyzed samples. Results showed that Cr levels in all tested vegetable species were below MPC values recommended by the FAO/WHO organization. The largest chromium accumulator was spinach, with average values of 2.3μg/g, followed by beetroot and parsnips with an average concentration of 1.4μg/g. The highest average content of Ni in all analyzed vegetable species was also recorded in spinach leaves, with an average value of 2.2μg/g, followed by broccoli (1.7μg/g) and tomatoes (1.5μg/g).

Health risks of heavy metal exposure through vegetable consumption near a large-scale Pb/Zn smelter in central China

Smelting of nonferrous metals is an important source of heavy metals in surface soil. The crops/vegetables grown on contaminated soil potentially impose adverse effects on human health. In this study, the contamination level of five heavy metals (Hg, Pb, Zn, Cd and Cu) in ten types of vegetables grown nearby a large scale Pb/Zn smelter in Hunan Province, China and the health risk associated with their consumption are assessed. Based on the data obtained from 52 samples, we find that Pb and Cd contributed to the greatest health risk and leafy vegetables tend to be more contaminated than non-leafy vegetables. Within 4 km radius of the smelter, over 75% of vegetable samples exceeded the national food standard for Pb; over 47% exceeded the Cd standard; and 7% exceeded the Hg standard. Heavy metal concentrations in vegetables measured within the 4 km radius are on average three times more elevated compared to those found at the control area 15 km away. Heavy metals in vegetables have dual sources of root absorption from soil and leaf adsorption from atmosphere. Health risk in terms of the hazard index (HI) at contaminated areas are 3.66 and 3.14 for adults and children, respectively, suggesting adverse health effects would occur. HI for both groups are mainly contributed by Pb (48%) and Cd (40%). Fortunately, vegetable samples collected at the control area are considered safe to consume.

Distribution of heavy metals in soils and vegetables and health risk assessment in the vicinity of three contaminated sites in Guangdong Province, China

ABSTRACTDue to rapid industrialization and urbanization, human activities like industrial and agricultural production, transportation, aggravate heavy metal pollution in soil and continue to endanger vegetables and human health. In this study, three contaminated areas affected by heavy metal pollution in Guangdong Province were investigated in terms of Cu, Zn, Pb, and Cd concentrations in soil and vegetables. Further analyses of the contamination status and potential risks to the health of residents consuming these vegetables were conducted. Results showed the following average heavy metal concentrations in vegetables and soil: Shaoguan > Guangzhou > Dongguan, indicating that mining has caused massive soil-heavy metal pollution. The heavy metal concentrations and Bioconcentration factors (BCFs) showed the following trend: leaf-vegetables > fruit-vegetables > root-vegetables, and those of vegetable type were as follows: Cd > Zn > Cu > Pb. The Nemero pollution index (PI) of all research region soils and hazard index (HI) exceeded 1. Hence, more attention should be paid to the potential for adverse health effects caused by the consumption of vegetables produced in these sites . Thus, effective measures are encouraged, with a focus on children due to their vulnerability to these heavy metals.

Bioavailability and soil-to-crop transfer of heavy metals in farmland soils: A case study in the Pearl River Delta, South China.

Soil-bound heavy metals are of great concern for human health due to the potential exposure via food chain transfer. In the present study, the occurrence, the bioavailability and the soil-to-crop transfer of heavy metals in farmland soils were investigated based on data from two agricultural areas, i.e. Sihui and Shunde in South China. Six heavy metals (As, Cu, Hg, Mn, Ni and Pb) were quantified in the farmland soils. The mean single pollution level indices (PI) were all lower than 1 except for Hg in soils from Shunde (PI = 1.51 ± 0.46), suggesting the farmland soils were within clean and slightly polluted by heavy metals. As, Cu, Ni and Pb were found to be mostly present in the non-bioavailable form. The majority of Hg was considered potentially bioavailable, and Mn was found to be largely bioavailable. Soil pH was an important factor influencing bioavailability of soil-bound heavy metals. The concentrations of heavy metals in vegetables from Sihui and Shunde were within the food hygiene standards, while the rice grain from Sihui was polluted by Pb (PI = 10.3 ± 23.4). Total soil concentrations of heavy metals were not correlated to their corresponding crop concentrations, instead, significant correlations were observed for bioavailable concentrations in soil. The results supported the notion that the bioavailability of the investigated heavy metals in the soil was largely responsible for their crop uptake. The soil-to-crop transfer factors based on bioavailable concentrations suggested that Cu, As and Hg in soils of the study area had greater tendency to be accumulated in the vegetables than other heavy metals, calling for further human health assessment by consuming the contaminated crops.

Trace metals concentration in vegetables of a sub-urban industrial area of Bangladesh and associated health risk assessment

Trace metals contamination of vegetables in the sub-urban industrial area of Bangladsh are increasing day by day. The mostly consumed vegetables like tomato (Lycopersicon lycopersicum), spinach (Spinacea oleracea), bean (Lablab purpureus), brinjal (Solanum melongena), potato (Solanum tuberosum), cauliflower (Brassica oleracea var botrytis), cabbage (Brassica oleracea var cupitata), and radish (Raphanus sativus) were collected from industrial area. Trace metals arsenic (As), manganese (Mn), zinc (Zn), cadmium (Cd) and lead (Pb) were measured using atomic absorption spectrophotometer (AAS). The descending order of trace metals followed the order of Zn>Mn>Pb>Cd>As. The results revealed that every vegetable contained the highest concentration of Zn range from 15 ± 1.4 to 50 ± 4.0 mg/kg fresh weight. Trace metals in vegetables exceeded the permissible level of FAO and WHO standard. The non-carcinogenic and carcinogenic risks were estimated on the basis of estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI) and target carcinogenic risks (TRs). The EDI values of all trace metals were below the maximum tolerable daily intake (MTDI). Total target hazard quotient (TTHQ) were greater than 1, indicated that if people consume these types of vegetables in their diet, they might pose risk to these metals. Finally, the total cancer risks (TRs) values were 6.4 × 10−3 for As and 8.7 × 10−5 for Pb which were greater than threshold value of USEPA (10−6), indicating that the consuming inhabitants of these vegetables are exposed to As and Pb with a lifetime cancer risk.

Assessment of heavy metal concentration in vegetables grown within fungicide treated Cocoa plantations in Akamkpa Local Government Area, Cross River State, Nigeria and implications to human health

The study was carried out to investigate the concentrations of heavy metals in soil samples and edible vegetables (Heinsia crinita and Gnetum africana) grown within fungicide treated cocoa plantation in Akamkpa communities of Cross River State Nigeria. In each sampling community, the edible vegetables and soil samples were collected for the period of three months (March to May) and were replicated three times. The levels of heavy metals in soil and edible vegetable samples collected were determined using Atomic Absorption Spectrophotometer. The concentrations of heavy metals in soil samples collected from fungicide treated coca plantations were higher than those recorded in the control location in all the sample locations. The concentrations of heavy metals in edible vegetables (Heinsia crinita and Gnetum africana) collected from fungicide treated cocoa plantations exceeded the maximum permissible limits values of heavy metals for edible vegetables. The soils and edible vegetables (Heinsia crinita and Gnetum africana) in the fungicide treated cocoa plantations in Akamkpa communities are contaminated by heavy metals and may pose serious adverse health effect to the consumers and the ecosystem.

Multiple factors impact the contents of heavy metals in vegetables in high natural background area of China

A field survey was conducted to investigate the concentrations of chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in vegetables, corresponding cultivated soils and irrigation waters from 36 open sites in high natural background area of Wuzhou, South China. Redundancy analysis, Spearman’s rho correlation analysis and multiple regression analysis were adopted to evaluate the contributions of impacting factors on metal contents in the edible parts of vegetables. This study concluded that leafy and root vegetables had relatively higher metal concentrations and adjusted transfer factor values compared to fruiting vegetables according to nonparametric tests. Plant species, total soil metal content and soil pH value were affirmed as three critical factors with the highest contribution rate among all the influencing factors. The bivariate curve equation models for heavy metals in the edible vegetable tissues were well fitted to predict the metal concentrations in vegetables. The results from this case study also suggested that it could be one of efficient strategies for clean agricultural production and food safety in high natural background area to breed vegetable varieties with low heavy metal accumulation and to enlarge planting scale of these varieties.

Detection of heavy metals in common vegetables at Varaždin City Market, Croatia.

The present study was aimed at the estimation of heavy metal content in vegetables sold at the city market of one of the densely populated Croatian cities, Varaždin, and to establish the relationship between their levels and possible sources of contamination. Twenty-eight samples of the most common diet vegetables (red and white potato, onion, carrot, common bean, lettuce, and cabbage) were randomly bought at the market in September and October 2013. Using the atomic absorption spectrometry method, concentrations of nine heavy metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) were measured in the selected samples. The results showed that, in five out of 28 samples analysed, six concentrations exceeded the maximum levels provided for in the regulations: five for Pb and one for Cd. Maximum regulated levels for Pb were exceeded in two samples of red potato, two samples of common bean, and one sample of carrot (17.9 %), and for Cd in a sample of red potato (3.6 %). In conclusion, the cause of the overstepping of the maximum levels for Pb and Cd in the vegetables analysed was most likely the contaminated soil. The possible sources of soil contamination include traffic, nearby industry, floodwaters of rivers and streams, and the use of pesticides and fertilisers in agricultural production.

Potential use of sludge cake from paper mill wastewater treatment as degradable flower pot.

Sludge cake produced in paper mill industries is disposed into a landfill and may cause the environmental and health problems. Now many researchers have tried to recycle rigid materials from it for the purpose of decreasing its volume. The aims of this study were to clarify three hypotheses: (1) whether a flower pot would be economically made from sludge cake, (2) whether it would be safe for environment, and (3) when vegetables would grow enough in it, whether they would be safe for human consumption. Sludge cake was mixed with soil (soil texture: heavy clay). The circular plaster mold was used as a fixed mold. As the toxicological testing, leaching test and seed germination test were used. Heavy metal concentrations in vegetables grown in the flower pot were measured. The flower pot was sufficiently formed by drying in natural open air. The results of leaching test showed three heavy metals, lead, nickel and copper, were lower than the standard in Thailand. The seed germination test suggested no negative effects of the flower pot on the germination of Chinese kale. Lead concentrations in the Chinese kale were higher than the recommended maximum level in leafy vegetables. The new flower pot can be made from sludge cake with soil. It has the possibility to have no negative effect on the environment. Although the vegetables grown in this flower pot are not suitable to eat, this flower pot has the possibility to solve the environmental and health problems.

Measurement of metal bioaccessibility in vegetables to improve human exposure assessments: field study of soil-plant-atmosphere transfers in urban areas, South China.

The quality of cultivated consumed vegetables in relation to environmental pollution is a crucial issue for urban and peri-urban areas, which host the majority of people at the global scale. In order to evaluate the fate of metals in urban soil-plant-atmosphere systems and their consequences on human exposure, a field study was conducted at two different sites near a waste incinerator (site A) and a highway (site B). Metal concentrations were measured in the soil, settled atmospheric particulate matter (PM) and vegetables. A risk assessment was performed using both total and bioaccessible metal concentrations in vegetables. Total metal concentrations in PM were (mgkg-1): (site A) 417 Cr, 354 Cu, 931 Zn, 6.3 Cd and 168 Pb; (site B) 145 Cr, 444 Cu, 3289 Zn, 2.9 Cd and 396 Pb. Several total soil Cd and Pb concentrations exceeded China's Environmental Quality Standards. At both sites, there was significant metal enrichment from the atmosphere to the leafy vegetables (correlation between Pb concentrations in PM and leaves: r=0.52, p<0.05) which depended on the plant species. Total Cr, Cd and Pb concentrations in vegetables were therefore above or just under the maximum limit levels for foodstuffs according to Chinese and European Commission regulations. High metal bioaccessibility in the vegetables (60-79%, with maximum value for Cd) was also observed. The bioaccessible hazard index was only above 1 for site B, due to moderate Pb and Cd pollution from the highway. In contrast, site A was considered as relatively safe for urban agriculture.

Public Health Risk Assessment of Heavy Metal Uptake by Vegetables Grown at a Waste-water-Irrigated Site in Dhaka, Bangladesh.

Wastewater is often used in developing countries for irrigation of crops. This wastewater often contains a number of heavy metals which are harmful to human health due to their non-biodegradable nature, long biological half-lives and their potential to accumulate in different body parts. There are many potential risks to human health from heavy metal contamination of vegetables grown at waste-water-irrigated sites. This study was carried out to assess the concentration of heavy metals and the risk to human health by heavy metals (lead (Pb), nickel (Ni) and arsenic (As)) through the intake of locally grown vegetables collected from wastewater irrigated agricultural fields. The objectives of the present study were to determine concentrations of heavy metals in vegetables collected from the wastewater-irrigated fields, to calculate daily intake of heavy metals from the consumption of vegetables for both adults and children, and to evaluate their potential health risk. Twenty-seven samples of nine different types of vegetables were analyzed by an Atomic Absorption Spectrometer (AAS) (Varian AAS 240 F S). The range of various metals in waste-water irrigated vegetables were not detected (ND)-0.188, 0.072-1.069 and ND-0.076 mg/kg for Pb, Ni and As, respectively. The highest mean concentration of all metals was detected in jute leaf, except for Pb which was found in the stem amaranth leaf. The mean concentration of all metals in all vegetables was within the safe limits of the World Health Organization/Food and Agricultural Organization (WHO/FAO) and China's national standards. The health risk index was more than 1 for As in jute leaf for both adults and children. The metal pollution index was highest (0.16 mg/kg) in jute leaf, whereas green papaya showed the lowest metal pollution index (MPI) value (0.005 mg/kg). Among all vegetables tested, the highest intake values of Ni and As were from consumption of jute leaf and the highest intake values of Pb from consumption of stem amaranth leaf for both adults and children. Higher values in the metal pollution index and health risk index indicate heavy metal contamination in wastewater-irrigated soils that present the potential for a significant negative impact on human health.

Slash-and-char: An ancient agricultural technique holds new promise for management of soils contaminated by Cd, Pb and Zn

Heavy metal contamination of agricultural soils is of worldwide concern. Unfortunately, there are currently no efficient and sustainable approaches for addressing this concern. In this study, we conducted a field experiment in which an agricultural soil highly contaminated by cadmium (Cd), lead (Pb) and zinc (Zn) was treated on-site by an ancient agricultural technique, ‘slash-and-char’, that was able to convert the biomass feedstock (rice straw) into biochar in only one day. We found evidence that in comparison to the untreated soil, the treated soil was associated with decreased bioavailability of the heavy metals and increased vegetable yields. Most importantly, the treatment was also coupled with dramatic reductions in concentrations of the heavy metals in vegetables, which made it possible to produce safe crops in this highly contaminated soil. Collectively, our results support the idea that slash-and-char offers new promise for management of soils contaminated by Cd, Pb and Zn.

Heavy metal content in vegetables and fruits cultivated in Baia Mare mining area (Romania) and health risk assessment.

Information about heavy metal concentrations in food products and their dietary intake are essential for assessing the health risk of local inhabitants. The main purposes of the present study were (1) to investigate the concentrations of Zn, Cu, Pb, and Cd in several vegetables and fruits cultivated in Baia Mare mining area (Romania); (2) to assess the human health risk associated with the ingestion of contaminated vegetables and fruits by calculating the daily intake rate (DIR) and the target hazard quotient (THQ); and (3) to establish some recommendations on human diet in order to assure an improvement in food safety. The concentration order of heavy metals in the analyzed vegetable and fruit samples was Zn > Cu > Pb > Cd. The results showed the heavy metals are more likely to accumulate in vegetables (10.8-630.6 mg/kg dw for Zn, 1.4-196.6 mg/kg dw for Cu, 0.2-155.7 mg/kg dw for Pb, and 0.03-6.61 mg/kg dw for Cd) than in fruits (4.9-55.9 mg/kg dw for Zn, 1.9-24.7 mg/kg dw for Cu, 0.04-8.82 mg/kg dw for Pb, and 0.01-0.81 mg/kg dw for Cd). Parsley, kohlrabi, and lettuce proved to be high heavy metal accumulators. By calculating DIR and THQ, the data indicated that consumption of parsley, kohlrabi, and lettuce from the area on a regular basis may pose high potential health risks to local inhabitants, especially in the area located close to non-ferrous metallurgical plants (Romplumb SA and Cuprom SA) and close to Tăuții de Sus tailings ponds. The DIR for Zn (85.3-231.6 μg/day kg body weight) and Cu (25.0-44.6 μg/day kg body weight) were higher in rural areas, while for Pb (0.6-3.1 μg/day kg body weight) and Cd (0.22-0.82 μg/day kg body weight), the DIR were higher in urban areas, close to the non-ferrous metallurgical plants SC Romplumb SA and SC Cuprom SA. The THQ for Zn, Cu, Pb, and Cd was higher than 5 for <1, <1, 12, and 6% of samples which indicates that those consumers may experience major health risks.