Characterization of metals in indoor dusts from electronic workshops, cybercafés and offices in southern Nigeria: Implications for on-site human exposure

Systematic literature review of heavy metal contamination of the Nigerian environment from e-waste management: Associated health and carcinogenic risk assessment

E-waste -the aftermath of large amount of electrical and electronic equipment ferried into Africa from which Nigeria receives a significant chunk, is composed of components known to be hazardous to health. Composition of series of heavy metals (HMs) in e-waste is traceable to many health conditions including cancer which is hitherto incompletely understood. This study harmonizes primary data on HMs from e-waste in different Nigerian environmental media including the air, soil, surface dust, water and plant. We estimated the possible health implications, single and aggregative soil and water pollution indices both in adult and children categories, carcinogenic and non-carcinogenic risks secondary to HM exposure and mapped out the possible mechanism of carcinogenesis. Analysis showed that soil, water, surface dust and plant matrices in Nigerian environment are variedly but considerably contaminated with combination of HMs. The significantly high values of the hazard quotient and hazard index of both water and surface dust matrices are indicative of adverse health effect of the non-carcinogenic risk. The highest HQ is generated by Pb and Cr through dermal exposure to soil and surface dust with mean values of 1718.48, 1146.14, 1362.10 and 1794.61 respectively among Nigerian children followed by the oral exposure. This pattern of observation is similar to that obtained for adult category. HI due to Pb and Cr in soil constitutes the highest HI (2.05E+03 and 1.18E+03 respectively) followed by surface dust. However, this study precipitates the observation that children are more at health risk than adults in contaminated environment. Carcinogenic risk also follows the same pattern of expression in the Nigerian environment. We conclude that exposure to e-waste poses significant carcinogenic and non-carcinogenic health risks and the induction of toxicity may be mediated via DNA damage, oxidative stress and inflammatory/immune cells dysfunction in Nigerian environment.

Occurrence and potential release of heavy metals in female underwear manufactured in China: Implication for women's health

Underwear is a potential source of women's exposure to heavy metals owing to its direct contact with the skin, especially the skin of the vagina and vulva, which has a strong absorptive capacity. However, information regarding the prevalence of metals in female underwear, and its potential hazards, remains scarce. In the present study, we examined the concentrations and potential release of Cr, Co, Ni, Cu, As, Cd, Sb, and Pb in brassieres and briefs manufactured in China. We detected higher levels of Pb and moderate levels of other metals, relative to the metal levels reported for other textiles in the literature. Cu, As, Ni and Cd, had higher migration rates (MRs) from the underwear, with medians of 100%, 100%, 30.1%, and 20.7%, respectively. The median MRs of the other metals were in the range 1.07%-15.7%. On the whole, the total and extractable concentrations of these metals differed by item and fabric type. The pollution of raw materials and the use of chemical additives containing metals commonly contributed to the metals in the underwear. On the basis of the exposure estimation, the non-carcinogenic risks posed by the underwear metals were acceptable, but the carcinogenic risks from the metals in 5.18% of brassiere samples exceeded the acceptable level.

Urinary Levels of 14 Metal Elements in General Population: A Region-Based Exploratory Study in China

Metal pollution may lead to a variety of diseases; for this reason, it has become a matter of public concern worldwide. However, it is necessary to use biomonitoring approaches to assess the risks posed to human health by metals. In this study, the concentrations of 14 metal elements in 181 urine samples obtained from the general population of Gansu Province, China, were analyzed using inductively coupled plasma mass spectrometry. Eleven out of fourteen target elements had detection frequencies above 85%, namely, Cr, Ni, As, Se, Cd, Al, Fe, Cu and Rb. The concentrations of most metal elements in the urine of our subjects corresponded to the medium levels of subjects in other regional studies. Gender exerted a significant influence (p < 0.05) on the concentrations of Tl, Rb and Zn. The concentrations of Ni, As, Pb, Sr, Tl, Zn, Cu and Se showed significant differences among different age groups and the age-related concentration trends varied among these elements. There were significant differences in the urine concentrations of Zn and Sr between those subjects in the group who were frequently exposed to soil (exposed soil > 20 min/day) and those in the group who were not, indicating that people in regular contact with soil may be more exposed to metals. This study provides useful information for evaluating the levels of metal exposure among general populations.

Potentially Harmful Elements Associated with Dust of Mosques: Pollution Status, Sources, and Human Health Risks

Potentially harmful elements (PHEs) associated with dust generated from anthropogenic sources can be transported into mosques and deposited on the filters of the air-conditioners (AC); thereby, children and adults are exposed to such PHEs while visiting mosques. Data dealing with the assessment of PHEs pollution and its human health risk in mosques dust in Saudi Arabia are scarce. Therefore, this work aims to examine the levels and pollution status of PHEs in AC filter dust (ACFD) of mosques and their associated human health risk in three Saudi cities: Jubail, Jeddah, and Dammam metropolitan. A similar concentration pattern of PHEs is observed in three cities' mosques with noticeably higher concentrations than both global crustal and local background values for Zn, Cu, Pb, As, and Cd only. Except for Fe, Al, and Mn, the highest PHEs concentrations were found in Jeddah (1407 mg/kg), followed by Dammam (1239 mg/kg) and Jubail (1103 mg/kg). High PHEs' concentrations were also recorded in mosques located near workshops and suburban areas compared to urban areas. Based on the spatial pattern, enrichment factor, geo-accumulation index, pollution load index, and ecological risk values, Jubail, Jeddah, and Dammam have shown moderate pollution levels of Cd, As, Pb, and Zn. On the other hand, Cu. Zn, Cu, Cr, Pb, Ni, As, and Cd had degrees of enrichment levels that varied from significantly enriched to extremely highly enriched in the ACFD of the three cities. Heavy pollution is found in Jubail, which posed a higher potential ecological risk than in Jeddah and Dammam. Cd presents the highest ecological risk factors (ER) in the three cities. Carcinogenic and non-carcinogenic risks for children and adults follow the order: Jeddah > Dammam > Jubail, and the ingestion pathway was the main route for exposure. Carcinogenic and con-carcinogenic risks in the mosques of the various studied cities were generally within the acceptable range.

Spatial Distribution, Contamination Levels, and Health Risk Assessment of Potentially Toxic Elements in Household Dust in Cairo City, Egypt

Urban areas’ pollution, which is owing to rapid urbanization and industrialization, is one of the most critical issues in densely populated cities such as Cairo. The concentrations and the spatial distribution of fourteen potentially toxic elements (PTEs) in household dust were investigated in Cairo City, Egypt. PTE exposure and human health risk were assessed using the USEPA’s exposure model and guidelines. The levels of As, Cd, Cr, Cu, Hg, Mo, Ni, Pb, and Zn surpassed the background values. Contamination factor index revealed that contamination levels are in the sequence Cd > Hg > Zn > Pb > Cu > As > Mo > Ni > Cr > Co > V > Mn > Fe > Al. The degree of contamination ranges from considerably to very high pollution. Elevated PTE concentrations in Cairo’s household dust may be due to heavy traffic emissions and industrial activities. The calculated noncarcinogenic risk for adults falls within the safe limit, while those for children exceed that limit in some sites. Cairo residents are at cancer risk owing to prolonged exposure to the indoor dust in their homes. A quick and targeted plan must be implemented to mitigate these risks.

Occurrence, Distribution, and Human Exposure of Emerging Liquid Crystal Monomers (LCMs) in Indoor and Outdoor Dust: A Nationwide Study

Liquid crystal monomers (LCMs) are a class of emerging, persistent, bioaccumulative, and toxic organic pollutants. They are detected in various environmental matrixes that are associated with electronic waste (e-waste) dismantling. However, their occurrence and distribution in indoor and outdoor dust on a national scale remain unknown. In this study, a dedicated target analysis quantified a broad range of 60 LCMs in dust samples collected across China. The LCMs were frequently detected in indoor (n = 48) and outdoor dust (n = 97; 37 sampled concomitantly with indoors dust) from dwellings, and indoor dust from cybercafés (n = 34) and phone repair stores (n = 22), with median concentrations of 41.6, 94.7, 106, and 171 ng/g, respectively. No significant spatial difference was observed for the concentrations of the total LCMs among distinct geographical regions (p > 0.05). The median daily intake values of the total LCMs via dust ingestion, dermal contact, and inhalation were estimated at 1.50 × 10^-2, 2.90 × 10^-2, and 8.57 × 10^-6 ng/kg BW/day for adults and 1.47 × 10^-1, 1.22 × 10^-1, and 2.18 × 10^-5 ng/kg BW/day for children, respectively. These estimates suggested higher exposure risks for children and indicated that dust ingestion and dermal contact significantly contribute to the human intake of LCMs. The microenvironmental pollution levels of LCMs together with the potential exposure risks associated with some of these chemicals are of concern for human health.

Source identification of pollution and health risks to metals in household indoor and outdoor dust: A cross-sectional study in a typical mining town, China

Dust is regarded as an important pathway of heavy metal(loid)s to the human body. Health risks posed by metal(loid)s from household dust are of particular concern. However, the contamination and sources of heavy metal(loid)s in household dust environments, as well as source identification of health risks related to heavy metal(loid)s from household dust for vulnerable populations such as children, have not been thoroughly studied in China, particularly for the areas involved with industrial activities such as ore mining. Thus, a cross-sectional study was conducted in a rural area famous for Pb/Zn ore mining, to assess the pollution sources and health risks of heavy metal(loid)s from household indoor and outdoor dust and to identify the contribution of household dust to the health risks for children. The results indicated that household environment was heavily contaminated by metal(loid)s, which were mainly attributed to mining activity. Meanwhile, the indoor/outdoor ratio and the redundancy analysis indicated that there were other pollution sources in indoor environments such as coal combustion, materials for interior building and decoration. Vapor inhalation was the main exposure pathway for Hg, while ingestion was the predominant pathway for other metal(loid)s. Although the cancer risks were relatively low, the HIt from household indoor and outdoor dust (2.19) was about twice the acceptable limit (1) and was primarily from Pb (64.52%) and As (23.42%). Outdoor dust was a larger contributor to the HI of Sb, As, Cr, Cd, Zn and Pb, which accounted for 51.37%, 58.63%, 52.14%, 59.66%, 52.87% and 64.47%, respectively, and the HIt was mainly from outdoor dust (60.76%). These results indicated that non-cancer health risks were largely from outdoor dust exposure, and strengthened the notion that concern should be given to the potential health risks from metal(loid)s in household dust both originating from mining activity and indoor environmental sources.

Characteristics and health risk assessment of heavy metal contamination from dust collected on household HVAC air filters

Heavy metals associated with airborne particulate matter are detrimental to human health, but risk assessment is difficult due to the technical challenges of determining exposure rates. In houses and other buildings, the heating, ventilation and air conditioning (HVAC) system is equipped with an air filter that captures airborne particulate matter from the indoor air that enters the HVAC system. This study used the air filter dust as a proxy for the heavy metal exposure of children and adults, based on a household study in Kuwait. Air filter dust contained from 12.5 ± 5 mg Co/kg dust to 14 453 ± 5046 mg Fe/kg dust. Houses had high levels of Fe, Al, Zn, and Mn and relatively low concentrations of As and Co. Source apportionment revealed that metals in air filter dust were from natural and anthropogenic sources, including vehicular emissions, fossil fuel combustion, and metals-related industries. The total Hazard Index (HI; Σ exposure routes) for heavy metals was >1 for children and adults. Total cancer risks (TCR; Σ exposure routes) were 5.93 × 10^-3 (95% CI: 5.28 × 10^-3- 6.59 × 10^-3) for children and 5.16 × 10^-3 (95% CI: 4.59 × 10^-3 - 5.73 × 10^-3) for adults. Heavy metals, particularly the Cr and Pb concentrations, contribute to the non-carcinogenic and carcinogenic health risks of children and adults in Kuwait households.

Characteristics, source apportionment and health risk assessment of heavy metals exposure via household dust from six cities in China

To investigate the characteristics and health risks of heavy metals in household dust in urban and rural areas during heating and non-heating period in 2016-2017, 762 dust samples and 381 questionnaires from 381 households were collected from Dalian, Taiyuan, Lanzhou, Shanghai, Wuhan, and Chengdu in China. The results indicated that Dalian was the most polluted city, while Shanghai and Chengdu were the least polluted cities during the study period. Longer ventilation times led to higher concentrations of heavy metals, and the weighting of heating duration exceeded that of heating type. Soil was the dominant contributor to household dust for Hg, Ni, Cu, Zn, and As, whereas Pb primarily originated from traffic. The non-carcinogenic and carcinogenic risks associated with heavy metals in household dust were acceptable, with ingestion being the primary exposure route. The risk of adverse health effects caused by heavy metal intake via household dust in urban areas was higher than that in rural areas, and increased during household heating period. Ingestion was the most significant route leading to adverse health effects due to heavy metals in household dust. The exception was the carcinogenic risk associated with Ni, which is known to enter the human body mainly via inhalation.

Heavy metals in indoor dust: Spatial distribution, influencing factors, and potential health risks

Given the large proportion of time that people spend indoors, the potential health risks posed by heavy metals in the indoor environment deserve greater attention. A global-scale assessment of heavy metal contamination in indoor dust was conducted in this study based on >127 articles published between 1985 and 2019. The pollution levels, spatio-temporal variations, sources, bioaccessibilities, influencing factors, and health risks of heavy metals associated with indoor dust were analyzed. Children's blood lead levels (BLLs) were also estimated using the integrated exposure uptake biokinetic model. The results indicated that the median concentrations of Cu and Zn in 71.9% and 71.0% of the study sites surpassed the corresponding permissible limits, 100 and 300 mg/kg, respectively; thus, their control should be given priority. Heavy metal concentrations in indoor dust from different areas of the world varied greatly, which was closely associated with the type of local human activities, such as mining, melting, e-waste recycling and Pb-related industries. The bioaccessibilities of some key elements, e.g., Pb, Cd, Cu, and Zn, in household dust were high. The levels of heavy metals in indoor dust were mainly affected by a combination of outdoor and indoor sources and related critical factors, and future studies should focus on quantifying the contributions of different sources. Based on the health risk assessment, dust Pb exposure is a major health concern in e-waste recycling areas, which warrants greater attention. 49.8%, 36.8% and 14.4% of study sites showed BLLs exceeding 35 μg/L (threshold limit in Germany), 50 μg/L (threshold limit in the USA), or 100 μg/L (threshold limit in China), respectively. Finally, Pb exposure from indoor dust represents a major contributor to children's blood Pb poisoning in many developing countries. This study details the overall heavy metal contamination status of indoor dust and provides insights for policymakers with respect to pollution prevention measures.

Concentration and risk assessment of toxic metals in indoor dust in selected schools in Southeast, Nigeria

The health risk of students’ exposure to some potentially toxic metals in classroom dusts in Southeast, Nigeria was assessed. Dust particles were collected from classrooms in some public high schools and digested with aqua regia before analysis for selected metals by atomic absorption spectrophotometry. The geoaccumulation index, contamination factor and the pollution load index were assessed from the metal concentrations of the dust. Hazard quotient and cancer risk index were used to estimate the potential health risk of students’ exposure to the metals in the dust. The metal concentrations (mg/kg) were in the ranges of 1.57–175.38 (Cr); 0.93–463.28 (Cu); 31.94.76–6623.41 (Fe); 4.96–143.98 (Ni); 2.64–375.27 (Zn); and 2.35–53.96 (Pb).The geo-accumulation index values showed that all the dust samples were polluted with Fe and Cr; and unpolluted with other metals with few exemptions. The contamination factor values showed that all the schools but one had a low contamination status due to Ni and Cu. There was moderate contamination by Pb at all the schools but two. All the schools had high contamination of Cr and Fe. The pollution load index indicated that the quality of all the classrooms was deteriorated. The calculated values of hazard quotient indicated that ingestion of dust at most of the classrooms would have no significant risk of non-carcinogenic effects on the health of the students. Dermal contact with the dust at all the classrooms would expose students to adverse effects of Fe. There will be adverse effect due to Pb for dermal contact with dust at most of the schools. Ingestion of dust particles at classrooms in all the schools would have carcinogenic effect due to Ni. Correlation analysis indicated that the sources of the metals varied. This study provided baseline data for relevant bodies to use in monitoring and controlling pollution so as to protect students from toxic metals.

Insights into the anthropogenic load and occupational health risk of heavy metals in floor dust of selected workplaces in an industrial city of Iran

The levels of Cd, Cr, Cu, Fe, Mn, Pb and Zn were determined in floor dusts from mechanical (MRWs) and battery repairing workshops (BRWs) in Yazd, Iran. The study aimed to evaluate the anthropogenic contribution to the presence of heavy metals (HMs), the possible sources and the related risks that could arise from occupational exposure in the studied workplace microenvironments. Among the analyzed heavy metals, Cu, Pb and Zn exhibited enhanced concentrations in the floor dusts. The EF calculations showed an extremely severe enrichment of HMs, especially for Cd, Cu and Pb, while floor dusts were characterized as "extremely polluted" with regards to those metals. In any case, both EF and I_geo values were significantly higher in the BRWs. These results were also supported by NIPI and PLI values, while contour maps of PLI values in both MRWs and BRWs outlined workshops in N-NE part of Yazd as more impacted compared to other spatial locations. Principal component analysis (PCA) and Pearson's correlation outscored workshops activities as the principal sources of heavy metals. The health risk assessment suggested considerable non-carcinogenic risks regarding Pb in the BRWs which exhibited HQ_ing (mean 2.91) and HI (mean 3.03) values higher than safe level. Regarding carcinogenic risks, CR values for both Cd and Cr were below the safe level (1.0 × 10^-6). The occupational exposure to Pb was evaluated through the predicted BLL values, where with averages of 3.33 μg/dl and 21.4 μg/dl for MRWs and BRWs workers, respectively, indicated a severe Pb exposure for BRWs workers.

Metal(loid) bioaccessibility and children's health risk assessment of soil and indoor dust from rural and urban school and residential areas

This study focused on the oral bioaccessibility and children health risks of metal(loid)s (As, Cd, Cr, Cu, Ni, Pb and Zn) in soil/indoor dust of school and households from Lanzhou, China. The simple bioaccessibility extraction test method was applied to assess bioaccessibility, and children's health risk was assessed via statistical modeling (hazard quotients, hazard index and incremental lifetime carcinogenic risk). Metal(loid) content and bioaccessibility in indoor dust samples were significantly higher than those in corresponding soil samples (p < 0.05). The order for mean values of bioaccessibility of the elements in soil was as follows: Cd (57.1%) > Zn (44.6%) > Pb (39.9%) > Cu (33.2%) > Ni (12.4%) > Cr (5.3%) > As (4.4%), while for indoor dust, the order was: As (73.0%) > Cd (68.4%) > Pb (63.3%) > Zn (60.4%) > Cu (36.5%) > Ni (25.2%) > Cr (13.6%). The Pearson correlation coefficient showed that metal(loid) bioaccessibility was in general significantly negatively correlated to the Al, Fe and Mn contents. Neither noncarcinogenic nor carcinogenic risks exceeded the tolerance interval for 3-5- and 6-9-year-old children for all elements. They both were mostly attributed to As considering metal(loid)s types and to school indoor dust considering sources. Therefore, maintaining interior sanitation would be an effective measure to reduce the potential health effects of indoor dust on children.

PM2.5 and ozone in office environments and their potential impact on human health

It is important to have good indoor air quality, especially in indoor office environments, in order to enhance productivity and maintain good work performance. This study investigated the effects of indoor office activities on particulate matter of less than 2.5 μm (PM_2.5) and ozone (O₃) concentrations, assessing their potential impact on human health. Measurements of indoor PM_2.5 and O₃ concentrations were taken every 24 h during the working days in five office environments located in a semi-urban area. As a comparison, the outdoor concentrations were derived from the nearest Continuous Air Quality Monitoring Station. The results showed that the average 24 h of indoor and outdoor PM_2.5 concentrations were 3.24 ± 0.82 μg m^-3 and 17.4 ± 3.58 μg m^-3 respectively, while for O₃ they were 4.75 ± 4.52 ppb and 21.5 ± 5.22 ppb respectively. During working hours, the range of PM_2.5 concentrations were 1.00 μg m^-3 to 6.10 μg m^-3 while for O₃ they were 0.10 ppb to 38.0 ppb. The indoor to outdoor ratio (I/O) for PM_2.5 and O₃ was <1, thus indicating a low infiltration of outdoor sources. The value of the hazard quotient (HQ) for all sampling buildings was <1 for both chronic and acute exposures, indicating that the non-carcinogenic risks are negligible. Higher total cancer risk (CR) value for outdoors (2.67E-03) was observed compared to indoors (4.95E-04) under chronic exposure while the CR value for acute exposure exceeded 1.0E-04, thus suggesting a carcinogenic PM_2.5 risk for both the indoor and outdoor environments. The results of this study suggest that office activities, such as printing and photocopying, affect indoor O₃ concentrations while PM_2.5 concentrations are impacted by indoor-related contributions.

Soil elemental concentrations, geoaccumulation index, non-carcinogenic and carcinogenic risks in functional areas of an informal e-waste recycling area in Accra, Ghana

This study assesses the distribution, contamination and human health risks of major, minor and trace elements in the topsoil and subsoil of two informal e-waste recycling sites in Accra, Ghana. Metal concentrations in Agbogbloshie exceeded the Dutch Soil intervention values with exceedances of 72%, 57%, 57%, 38%, 16%, 2% for Cu, Zn, Pb, Ba, Cd and As respectively. Metal concentrations in Ashaiman exceeded the Dutch Soil intervention values with exceedances of 62%, 57% and 46% for Cu, Zn and Pb respectively. Geoaccumulation indices indicated that the topsoils of the burn area and dismantling areas of Agbogbloshie e-waste recycling site were strongly contaminated by Pb and uncontaminated by Cr, Fe, As and Ba. Lead (Pb) contributed greatly to non-carcinogenic ingestion hazard quotient for residents living near Agbogbloshie and Ashaiman e-waste recycling sites while arsenic (As) presented carcinogenic risks to children from the dismantling area topsoils. Non-carcinogenic risks from ingestion were significant with children being more susceptible to non-carcinogenic ingestion risks than adults. Non-carcinogenic risks from dermal exposure were negligible. Hazard quotients of Pb for children in burn area topsoils and dismantling area topsoils were 7.4-7.6-fold greater than that for adults. The mean geoaccumulation indices values of Pb and Cu indicated extreme contamination of topsoils with these elements. A "novel environmental assessment tool" based on the Agency for Toxic Substances and Disease Registry (ASTDR) total impact points confirmed Pb and Cu as the most toxic elements.

The exposure of children to PM2.5 and dust in indoor and outdoor school classrooms in Kuala Lumpur City Centre

It is important to assess indoor air quality in school classrooms where the air quality may significantly influence school children's health and performance. This study aims to determine the concentrations of PM_2.5 and dust chemical compositions in indoor and outdoor school classroom located in Kuala Lumpur City Centre. The PM_2.5 concentration was measured from 19th September 2017-16th February 2018 using an optical PM_2.5 sensor. Indoor and outdoor dust was also collected from the school classrooms and ion and trace metal concentrations were analysed using ion chromatography (IC) and inductively couple plasma-mass spectrometry (ICP-MS) respectively. This study showed that the average indoor and outdoor 24 h PM_2.5 was 11.2 ± 0.45 µg m^-3 and 11.4 ± 0.44 µg m^-3 respectively. The 8 h PM_2.5 concentration ranged between 3.2 and 28 µg m^-3 for indoor and 3.2 and 19 µg m^-3 for outdoor classrooms. The highest ion concentration in indoor dust was Ca²⁺ with an average concentration of 38.5 ± 35.0 µg g^-1 while for outdoor dust SO₄^2- recorded the highest ion concentration with an average concentration of 30.6 ± 9.37 µg g^-1. Dominant trace metals in both indoor and outdoor dust were Al, Fe and Zn. Principle component analysis-multiple linear regression (PCA-MLR) demonstrated that the major source of indoor dust was road dust (69%), while soil dominated the outdoor dust (74%). Health risk assessment showed that the hazard quotient (HQ) value for non-carcinogenic trace metals was < 1 while the total cancer risk (CR) value for carcinogenic elements was below the acceptable limit for both indoor and outdoor dust through dermal and inhalation pathways, but not the ingestion pathway. This study suggests indoor contributions of PM_2.5 concentrations are due to the activities of the school children while the compositions of indoor and outdoor dust are greatly influenced by the soil/earth source plus industrial and traffic contribution.

Health implication of heavy metals exposure via multiple pathways for residents living near a former e-waste recycling area in China: A comparative study

Herein, crop (vegetables and rice, n = 30), soil (n = 14), dust (n = 12), and PM10 (n = 25) samples were collected to assess the environmental quality of a former e-waste recycling area and evaluate the related health risks. In dust and PM₁₀, the concentrations of heavy metals (Cd, Cu, Ni, Pb, and Zn) were lower than previously reported values, although the numbers for soil, vegetables, and rice remained high. The average accumulation factors of heavy metals in crops decreased in the order of Zn > Cd > Ni > Cu > Pb, and soil was identified as the largest contributor to crop pollution. Heavy metal ingestion largely occurred via rice consumption, which accounted for a significant fraction of the total average daily dose (ADD; 75.2-86.7% in children and 78.0-91.7% in adults), especially for Cd, Cu, Ni, and Zn. However, in the case of Pb, soil ingestion accounted for 48.9% of the ADD in adults, while in children, vegetable, rice, and dust ingestion accounted for 44.7%, 28.6%, and 23.7% of the ADD, respectively. The combined exposure hazard indices at the fifth, median, and 95th percentiles for all heavy metals were determined as 2.54, 9.40, and 40.1 for adults and as 3.75, 13.7, and 58.4 for children, respectively. In terms of health risk, crop consumption was identified as the major exposure pathway for both children and adults, featuring a contribution of 99.9%. In addition, the 95th percentile carcinogenic risks for Pb exceeded the acceptable level. Thus, this work shows that to reduce the health risk for local residents in the former e-waste area, more attention should be paid to soil repair.