Assessment of the Risks of Heavy Metal Contamination in Irrigation Water, Soils and Crops in Agricultural Fields Near Some Oil Fields

Heavy metal contamination in agricultural soils, water, and crops is a critical concern in developing regions due to its implications for food safety and public health. This study assessed the concentrations of six heavy metals – cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) – in soil, irrigation water, and commonly consumed vegetables from three sites in Gopalganj, Bangladesh. The sites represent a gradient of anthropogenic impact: a rural agricultural area (control), a mixed agriculture-urban area, and an industrial-adjacent area. Samples were analyzed using Atomic Absorption Spectroscopy (AAS) with rigorous quality control. Results showed that all metal concentrations in vegetables and soils were below international permissible limits, with mean levels in soils (e.g., Ni ~ 0.4 mg/kg, Cu ~ 0.5 mg/kg, Pb ~ 0.3 mg/kg) and vegetables (Zn ~ 0.4 mg/kg, other metals often not detectable) reflecting background conditions. Irrigation water contained trace metal levels near or below detection limits. Nevertheless, spatial trends were evident: soils at the industrial-influenced site had significantly higher Ni and Cu than the rural site (p < 0.05), and slight elevations of Cd, Pb, and Cr were noted in vegetables and water from impacted areas (though still within safe bounds). Pearson correlations suggested common sources for some metals (e.g., Pb–Cu, r ≈ 0.51; Ni–Pb, r ≈ 0.36; p < 0.05). A human health risk assessment indicated that the estimated dietary intakes of these metals through vegetables yield HQ and HI values well below 1, indicating no significant non-carcinogenic risk at present. These findings provide a timely baseline on heavy metal pollution in a fast-developing region of Bangladesh. While current contamination levels appear safe, the detectable influence of industrial activities underscores the need for ongoing monitoring and proactive measures to ensure environmental and food safety in the future. Diagrammatic representation of workflow process

The excessive application of fertilizers and of polluted irrigation water increases the trace metal level in an agricultural ecosystem. This study aimed to assess the concentrations of trace metals (Fe, Cu, Mn, and Zn) in irrigation water, field soil and crop plants. The contents of metals were analyzed by Atomic Absorption Spectroscopy. The range and hierarchy of trace metals concentration (µg/ml) in irrigation water are as follows, Fe (2.16 - 1. 53) > Zn (0.30 - 0.17) > Cu (0.18 - 0.11) > Mn (0.11-0.09). The concentration (µg/g) range in field soil showed in an order as Fe (9000- 6961.5) > Mn (984.6-408.9) > Cu (698.5-26.3) > Zn (145.3- 22.9). Moreover, crop plant parts showed maximum concentration (µg/g.dry weight) range for metal Fe (516.3 - 126.7) followed by Mn (169.7-0.4), Zn (78.8- 50) and least for metal Cu (70.5- 4.1). It was noticed that the Fe concentration in irrigation water is higher than the water quality standards proposed by the Food and Agriculture Organization. Furthermore, the field soil exhibited more Cu, and crops have accumulated excess Fe and Cu than the Indian and European Union guidelines. Further, we reported that among the all plant part, leaves are more prone to accumulate trace metals. The value of the transfer factor indicates that plant has low bioaccumulation potential for studied trace metals. Whereas the accumulation index shows that there is a significant Cu contamination in the field soil. So we suggest that farmers should avoid the application of copper-rich fertilizers.

Studies on peri urban farming in Zambia have not adequately tackled the issues pertaining to heavy metal contaminated wastewater irrigation farming. The study investigated heavy metal contamination of water, soils and crops at two peri urban areas in Zambia. Two study sites were New Farm Extension in Mufulira Town in the Copperbelt Province and Chilumba Gardens in Kafue Town in Lusaka Province. The heavy metals investigated were lead, copper, cobalt, nickel and chromium. These heavy metals were found to be higher than acceptable limits in wastewater used to irrigate crops and there are potential human health risks associated with consumption of heavy metal contaminated food crops which have implications on the livelihoods of people. Samples of water, soil and crops were collected and analysed for lead (Pb), copper (Cu), chromium (Cr), cobalt (Co) and nickel (Ni) using the Atomic Absorption Spectrometer (AAS). The data on heavy metals was analysed using mean, standard error and T-test. The results indicated that the levels of heavy metals in wastewater, soil and food crops were above acceptable limits at two study sites. It can be concluded that there was heavy metal contamination of wastewater, soil and food crops at the two peri-urban areas in Zambia. The study highlighted the actual levels of heavy metal contaminant uptake in food crops consumed by the peri urban population. The information from this study can be used by the relevant authorities to develop appropriate measures for monitoring and control of heavy metal contamination in wastewater irrigation farming systems in peri urban areas inZambia.

Human health risk assessment of heavy metals in soil and food crops in the Pearl River Delta urban agglomeration of China

The present study was conducted to determine the heavy metal contamination in soil with accumulation in plants in waste water irrigated areas. Results revealed that waste water contained lower concentrations of Cr, Zn, Cu, and Pb except Cd (0.03) than the permissible limits prescribed by the World Health Organization. The maximum metal concentrations occurred in Brassica oleracea (Zn 63.80, Cu 12.25, Cr 10.65, Pb 3.63, and Cd 0.56 mg Kg−1).The metal enrichment (EF of Cd 1.9, Cr2.9, Zn 4.8, Cu 6.5, and Pb 15.5) and degree of contamination (CF of Cd 2.9, Cr 2.0, Zn 2.3, Cu 2.7, and Pb 2.2) showed that accumulation of the five toxic metals increased during sewage irrigation as compared with the reference values, other Indian regions and globally. However, based on WHO standards for heavy metal contamination of soil and irrigation water, our data does not ensure safe levels for food.

The study investigated concentrations, distribution, and bioaccumulation of heavy metals in agriculture soil and crops irrigated by the Kali River of Uttar Pradesh, India. Soils and crop samples were collected from 17 locations along the river and analyzed for heavy metal concentrations. Metals in soil and plant were recorded as Fe > Zn > Mn > Cu > Ni > Pb > Cr > Cd and Mn > Fe > Zn > Cu > Cr > Ni > Pb > Cd, respectively. The bioaccumulation factor was < 1 that indicates lesser accumulation of metals in plants except for Cd, Mn, and Zn. Metal pollution index ranged between 1.84 and 6.62 and shows that crops growing at the S10 to S17 sites accumulate greater metal concentrations. Cluster analysis showed agglomeration of Cr-Pb-Cd, Cu-Ni-Mn, and Fe-Zn which revealed different sources of metal pollution. The present study shows low to moderate heavy metal pollution in Kali River irrigated areas thus consumption of agriculture produce may cause adverse health effects.

Background: The main goal of this study is to evaluate the potential human health risks associated with consuming vegetables contaminated by heavy metals at Sekenke gold mine. Methodology: Five heavy metals (Pb, Cd, Fe, Zn and Cr) were analyzed in soil and in green leafy vegetables (Amaranthus sp and cucurbita moschata) by XRF Rigaku Nex CG instrument, while Arsenic was examined by Atomic Absorption spectrometry (AAS) equipped with a continuous flow of Vapour Generation Accessory (VGA). Results: The average heavy metal concentrations in soils sample with mean average concentrations ± standard error (mg/kg) 204.646 ± 28.671 for Fe, 163.116 ± 16.658 for Cr. 52.403 ± 15.806 for Zn, 23.392 ± 18.049 for Pb, 21.331 ± 7.503 for As and 3.018 ± 0.842 for Cd. In GLV was observed that the average concentrations of As, Pb, Cd and Zn exceeded the maximum acceptable limit by FAO/WHO (2001) while Fe and Cr concentrations are lower than maximum acceptable limits. On average, Amaranthus species can contribute between 1.04% (Fe) to 7.15% (As) of the recommended daily intake (RDI) for these metals. While in Cucurbita moschata it ranges from 1.09% (Cr) to 5.47% (Cd). Conclusion: This study shows the contribution of non-essential elements (As, Pb, Cd and Cr) is high than essential elements (Fe and Zn). The HQ of Amaranthus sp ranges from 0.298 (Fe) to 9.930 (As) where about 67% of the analyzed metals have HQ &gt; 1, reveals probable adverse health effects. In cucurbita sp the HQ ranges from 0.383 (Fe) to 4.41 (As). For the heavy metals analyzed the trend for HQ via ingestion, were observed that 50% of the analyzed metals have HQ &gt; 1. Though, vegetable intake is just a proportion of food consumed, supplementary or complementary food that may include fish, rice and tobacco that are consumed can also contribute and/ increase amounts of heavy metals. Novelty: This study is beneficial to the individuals around the mine sites dealing with mineral materials associated with heavy metal contamination that affects their health through vegetable ingestion.

Wastewater is actively used for irrigation of vegetable and forage crops in arid lands due to water scarcity and cost advantages. The objective of this review was to assess the effect of wastewater (mixture sources) reuse in irrigation on soil, crop (vegetable and forage crops), animal products, and human health. The metadata analysis of 95 studies revealed that the mean of toxic heavy metals including nickel (Ni), chromium (Cr), cadmium (Cd), lead (Pb), and zinc (Zn) in untreated wastewater were higher than the world standard limits in wastewater-irrigated regions. Although heavy metals in treated wastewater were within the standard limits in those areas, the concentration of those toxic elements (Pb, Cd, Ni, Cr, and As) exceeded the allowable limits in both soil and vegetables’ edible parts. In fact, the concentration of heavy metals in vegetables’ edible parts increased by 3–9 fold when compared with those irrigated with fresh water. Escherichia coli in wastewater-irrigated soil was about 2 × 106 (CFU g−1) and about 15 (CFU g−1) in vegetables’ edible parts (leaf, bulb, tuber and fruit) while the mean total coliforms was about 1.4 × 106 and 55 (CFU g−1) in soil and vegetables’ edible parts, respectively. For human health risk assessment, the estimated daily intake (EDI) and human health risk index (HRI) ranged from 0.01 to 8 (EDI and HRI &gt; 1.0 associated with adverse health effects). Although the mean of EDI for heavy metals from wastewater-irrigated vegetables were less than 1, the HRI for Cd and Pb were above the limits for safe consumption. Overall, heavy metal levels in wastewater that used for irrigation of agricultural crops could be within the recommended levels by the world standards, but the long-term use of this reused water will contaminate soil and crops with several toxic heavy metals leading to potential carcinogenic risks to humans. Therefore, rigorous and frequent testing (wastewater, soil, and plant) is required in cultivated farms to prevent the translocation of heavy metals in the food chain.

Background: Heavy metal contamination in soils adversely affects plant growth, particularly in crops used for phytoremediation, such as sunflower (Helianthus annuus L.). Understanding the response of different sunflower varieties to heavy metal stress is crucial for developing effective phytoremediation strategies.Objective: This study aimed to evaluate the impact of nickel (Ni), cadmium (Cd), and lead (Pb) on the germination, growth attributes, and metal translocation of two sunflower varieties, Hysun-33 and FH-533.Methods: Sunflower seeds of Hysun-33 and FH-533 were sown in sand-filled pots treated with 0, 50, 100, 150, and 200 mM of Ni, Cd, and Pb. Germination rates, shoot and root lengths, and dry biomass were measured after 20 days. Metal concentrations in roots and shoots were analyzed using atomic absorption spectroscopy, and statistical analyses, including ANOVA and regression, were performed to assess the effects of metal concentrations.Results: Germination rates for Hysun-33 decreased from 79% at 0 mM to 0% at 200 mM, while FH-533 dropped from 75% to 5%. Shoot lengths decreased by 47% at 150 mM Ni, and root biomass was reduced by 62% under 200 mM Cd for both varieties.Conclusion: Cadmium posed the greatest threat to sunflower growth, emphasizing the need for enhanced metal tolerance in phytoremediation applications. Reducing heavy metal contamination in crops is vital for improving food safety and public health.

This study assesses heavy metal levels in the water, soil, and vegetables (swiss chard, lettuce, cabbage, collard green, tomato, green pepper, and carrot) irrigated with wastewater in Gamo, Ethiopia. The samples of soils, waters, and vegetables were randomly collected, processed, and analyzed for heavy metals using atomic absorption spectroscopy. The results obtained show that the mean concentrations of Cd, Cr, and Ni had the highest concentration, and Pb, Zn, and Cu had the lowest concentration in irrigation waters. The levels of Cd in the Kulfo river area and Chamo Lake area and Cu in most of the farm soils were also found to be higher than the guideline values. The study also revealed that the mean levels of Cd in most vegetables and Cr and Pb in some vegetables were higher than the maximum recommended limits set by the World Health Organization / Food and Agriculture Organization 2001. Among the vegetables, cabbage had the highest heavy metal content followed by Swiss-chard, carrot, tomato, collard green, green pepper, and lettuce. The Hazard quotient of Cu, and Ni of all samples of vegetables and Cd in some samples vegetables obtained exceeded unity. It signifies that there are potential health risks to the consumers. This study recommends regular monitoring of heavy metals in soils, waters, and foodstuffs to prevent excessive accrual in the food chain.

Determination of trace metals in vegetables using ICP-MS

Heavy metal (HM) contamination in soils of greenhouse vegetable production (GVP) systems has drawn increasing attention in terms of food safety. In the present study, 64 surface soils were sampled, and the concentrations of select HMs were determined using atomic absorption spectroscopy. The results showed that the concentrations of cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), nickel (Ni) and chromium (Cr) in the soils were (0.2±0.2) mg/kg, (26.5±8.4) mg/kg, (101.4±43.2) mg/kg, (29.1±8.6) mg/kg, (24.5±3.3) mg/kg, and (56.5±6.3) mg/kg, and the corresponding accumulation index (AI) values were 2.30, 1.10, 1.43, 1.45, 1.07, and 0.97, respectively. The spatial distribution of the HMs suggested that Cd pollution displays a fractionation effect, which may be related to the source of Cd and its mobility. The concentration of Zn was significantly correlated with that of other HMs, implying that a comprehensive interactive effect might occur between Zn and other HMs. Furthermore, the values of the potential ecological risk index (RI) ranged from 41.23 to 185.91, meaning that attention should be paid to HM contamination of GVP soils to ensure food quality and safety. Keywords: heavy metal contamination, cold region, greenhouse vegetable production (GVP), distribution, ecological risk, food quality, food safety DOI: 10.25165/j.ijabe.20191202.4306 Citation: Lv P, Wei Z M, Yu Z M, Zhang J Z, Wang L M. Heavy metal contamination in soils of greenhouse vegetable production systems in a cold region of China. Int J Agric & Biol Eng, 2019; 12(2): 98–102.

Source identification and risk assessment of heavy metals are ongoing hot topics in current research, but few studies have been performed on the linkage mechanism between them. In the past, the amount of heavy metals discharged was the identification criterion for high‐risk source but failed to consider different toxicity of heavy metals in the risk level of each pollution source. Therefore, it is impossible to accurately determine high‐risk pollution source. For this situation, this study introduced a risk assessment model based on the source apportionment model, which can quantitatively analyze the source‐based risk. Meanwhile, pollution assessment indexes and a risk assessment model were applied to evaluate the levels of pollution and risk of heavy metals, showing that lead (Pb) caused relatively serious pollution and arsenic (As) generated the highest ecological risk and noncarcinogenic risk. Positive matrix factorization (PMF) model identified and quantified the sources of heavy metals (coal‐related activities source, mixed source of mining and traffic emissions, industrial activity source, agricultural source related to the application of agrochemicals) with the corresponding contributions of 42, 30, 26, and 2%, respectively. Then PMF was combined with potential ecological risk index and human health risk assessment model to quantify the risk from pollution sources, indicating that the coal‐related activities source was the largest pollution source (31–36%) that caused human health risks, while the mixed source of mining and transportation emissions posed the greatest threat (29%) to the ecosystem health. Therefore, both sources should be identified as the priority pollution sources.

Severe contamination of carcinogenic heavy metals and metalloid in agroecosystems and their associated health risk assessment

This study evaluates the heavy metal (As, Cd, Cu, Hg, Pb, and Zn) contamination in soil, surface water, and crops in Uthai District, Ayutthaya Province, Thailand, an agricultural area located near an industrial park. Further, the blood levels of these metals in residents living in the study area are investigated. The concentrations of the six metals in soil were below the values permitted under the Soil Quality Standard, Thailand. In contrast, the concentrations of As and Hg in surface water exceeded the permissible limits. For the crops, all heavy metal values in eggplant, kale, and rice were at safe levels. However, in basil, both Hg and Cu levels exceeded the permissible limits, and in coriander, Hg content exceeded the permissible limit. Additionally, the potential health risks of heavy metal exposure through consumption of local crops were assessed using target hazard quotients (THQs) and hazard indices (HIs). The former values of the crops varied. 100.0% for As, 40% for Cd, 60% for Cu, 20% for Pb, and 30% for Zn of the analyzed samples had THQs above 1. This indicated that consumers were probably exposed to some non-carcinogenic health risk (except for Hg which was 0%). Of greater concern, the HI values of each consumed crop were > 1, indicating obvious risk of adverse health effect. Finally, the heavy metal levels in blood from a sample of local residents (n = 16) were assessed along with blood chemistry tests. The levels of all heavy metals were within the normal ranges. Nevertheless, heavy metal contamination in both the environment and food crops raise concerns of health risks to the residents of this area.