Epidemiology of norovirus infection in Nigeria: a systematic review and meta-analysis.

Human norovirus (HuNoV) is responsible for most cases of gastroenteritis worldwide, but information about the prevalence and diversity of HuNoV infections in lower-income settings is lacking. In order to provide more information about the burden and distribution of norovirus in Nigeria, we systematically reviewed original published research articles on the prevalence of HuNoV in Nigeria by accessing databases, including PubMed, Web of Science, ScienceDirect, Google Scholar, and African Journals Online (AJOL). The protocol for the review was registered on PROSPERO (registration number CRD42022308857). Thirteen relevant articles were included in the review, and 10 of them were used for meta-analysis. The pooled prevalence of HuNoV-associated gastroenteritis among children below 5 years of age in Nigeria, determined using the random-effects model, was 10.9% (95% CI, 6.7-16.7%). Among children below the age of 5 presenting with HuNoV infections, the highest prevalence was in children ≤2 years old (n = 127, 83%). The prevalence of HuNoV infections was seen to decrease with increasing age. In addition, HuNoV was detected in asymptomatic food handlers, bats, and seafoods. A total of 85 sequences of HuNoV isolates from Nigeria have been determined, and based on those sequences, the most prevalent norovirus genogroup was GII (84%). Genotypes GII.4 and GI.3 were the most frequently identified genotypes, with GII.4 constituting 46% of all of the HuNoVs identified in Nigeria. These results suggest a risk associated with cocirculation of emerging variants with known genotypes because of their recombination potential. Larger molecular epidemiological studies are still needed to fully understand the extent and pattern of circulation of HuNoVs in Nigeria.

Proximity to public green spaces and depressive symptoms among South African residents: a population-based study.

BACKGROUND: Exposure to green spaces has been suggested to improve mental health and may reduce the risk of depression. However, there is generally limited evidence on the association between green spaces and depression originating from low-and middle-income countries and Africa in particular. Here, we investigate the association between proximity to public green spaces and depressive symptoms among residents of Gauteng Province, South Africa. METHODS: We used data from the 2017/2018 Gauteng quality of life survey. We included all individuals aged 18 years or older residing in the nine municipalities of Gauteng Province that completed the survey (n = 24,341). Depressive symptoms were assessed using the Patient Health Questionnaire-2. Proximity to public green spaces was defined as self-reported walking time (either less or greater than 15 min) from individuals' homes to the nearest public green space. To assess the association between access to public green spaces and depressive symptoms, we used mixed-effects models, adjusted for age, sex, population group (African, Indian/Asian, Coloured (mixed race), and White), educational attainment, and municipality. We additionally performed stratified analyses by age, sex, educational attainment, and population group to evaluate whether associations differed within subgroups. Associations are expressed as prevalence ratios (PR) and their 95% confidence intervals (95% CI). RESULTS: We observed a 6% (PR = 0.94, 95%CI = 0.92-0.96) prevalence reduction in depressive symptoms for individuals who reported that the nearest public green space was less than 15 min from their homes as compared to those who reported > 15 min. After stratification, this inverse association was stronger among females, individuals aged 35-59 years,those with higher levels of educational attainment, and Coloured individuals as compared to their counterparts. CONCLUSION: Our findings suggest that public green spaces close to residential homes may be associated with a reduction in the occurrence of depressive symptoms among urban populations in resource-constrained settings like South Africa.

Wastewater-based SARS-CoV-2 airport surveillance: key trends at the Cape Town International Airport.

Monitoring of SARS-CoV-2 RNA in wastewater has revealed the role of mobility in the transmission of coronavirus disease (COVID-19), and the surveillance of airport wastewater in cities across the world has demonstrated how travel entry points can give an indication of trends in transmission. This study undertook wastewater surveillance at the Cape Town International Airport (CTIA) to assess the use of a WBE approach to provide supplementary information on the presence of COVID-19 at a key air travel entry point in South Africa. Grab wastewater samples (n = 55) were collected from the CTIA wastewater pump station and analysed using quantitative real-time polymerase chain reaction (qRT-PCR) method. The study found a correlation between the wastewater data and clinical cases reported in the City of Cape Town during various time periods and during the peak of a COVID-19 wave. Highly elevated viral loads in the wastewater were observed at times there was increased mobility through the airport. The study also revealed elevated viral load levels at the airport despite the stricter restrictions and through the lower restrictions. The study findings indicate wastewater surveillance and airports can provide supplementary information to airport authorities to assess the impacts of imposed travel restrictions.

Delineating the Spread and Prevalence of SARS-CoV-2 Omicron Sublineages (BA.1-BA.5) and Deltacron Using Wastewater in the Western Cape, South Africa.

This study was one of the first to detect Omicron sublineages BA.4 and BA.5 in wastewater from South Africa. Spearman rank correlation analysis confirmed a strong positive correlation between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral RNA in wastewater samples and clinical cases (r = 0.7749, P < .0001). SARS-CoV-2 viral load detected in wastewater, resulting from the Delta-driven third wave, was significantly higher than during the Omicron-driven fourth wave. Whole-genome sequencing confirmed presence of Omicron lineage defining mutations in wastewater with the first occurrence reported 23 November 2021 (BA.1 predominant). The variant spread rapidly, with prevalence of Omicron-positive wastewater samples rising to >80% by 10 January 2022 with BA.2 as the predominant sublineage by 10 March 2022, whilst on 18 April 2022 BA.4 and BA.5 were detected in selected wastewater sites. These findings demonstrate the value of wastewater-based epidemiology to monitor the spatiotemporal spread and potential origin of new Omicron sublineages.

A study protocol to evaluate the impact of a personal and domestic hygiene intervention on lead exposure in a community next to a mine dump.

BACKGROUND: Lead has been associated with adverse health effects, especially neurocognitive and behavioural effects, in children. Communities living close to mining land are at risk of elevated exposure to lead. METHODS: This paper outlines a before and after intervention study protocol to evaluate the impact of a personal and domestic hygiene intervention on lead exposure in a community located adjacent to a mine dump. In each participating household, parents or guardians will be interviewed using a structured questionnaire to obtain information on socio-demographic characteristics, living conditions, domestic hygiene practices and potential alternative sources of exposure to lead. A registered nurse will collect hand wipe samples from children aged one to five years, for whom parental consent and where possible child assent has been obtained. Environmental dust samples will be collected from the floors and/or windowsills of children's dwellings for lead content analysis. Soil samples will be collected from yards to determine lead content. An educational intervention will then be applied to the intervention group, including the engagement of households or guardians in an educational discussion on the sources, pathways of exposure, health effects of lead exposure and protective measures, with the aid of a specially designed educational brochure. Data will be analysed for descriptive and inferential statistics using Stata version 16. DISCUSSION: The study will determine whether the intervention led to a reduction in indoor dust lead levels, and if shown to be effective, will inform the development of an awareness campaign to reduce lead exposure in communities located in close proximity to mine dumps. TRIAL REGISTRATION: The study is retrospectively registered on ClinicalTrials.gov Protocol Registration and Results System with registration number NCT05265572 and first release date of 18th February 2022.

Exposure to lead and other toxic metals from informal foundries producing cookware from scrap metal.

Metal exposure remains a significant public health problem, particularly in the informal sector. The rise in informal foundries to cast scrap metal into artisanal cookware is widespread in low- and middle-income countries. The main aim of this study was to characterize metal exposure in artisanal cookware makers working in informal foundries in South Africa by measuring lead (Pb) in blood as well as sample metal concentrations on hands before and after work. The blood Pb distribution of the artisanal pot makers ranged from 1.1 to 4.6 µg/dl with the median blood Pb level being 2.1 µg/dl (IQR 1.7-2.5). The median blood Pb level in artisanal pot makers was 1.0 µg/dl higher compared with the non-exposed community members (p < 0.0001). Before-and-after handwipe sampling revealed a median increase in all 22 elements. Pre and post aluminum (Al) load on the handwipes revealed a 7.3 factor increase (0.53 and 3.9 mg Al/handwipe respectively) (p = 0.003). Hand Pb load before and after pot making revealed a 3.5-fold increase (median increase of 6.2 µg Pb/handwipe). An increase in backyard informal foundries may be linked to increased exposure to toxic metals for workers, family members and communities.

Recycled aluminium cooking pots: a growing public health concern in poorly resourced countries.

Lead exposure remains a significant public health problem, particularly in the informal sector. Recycling of scrap metal into artisanal pots is a growing concern in poorly resourced countries. Owing to the relatively light weight and low cost of the artisanal pots, as well as good conductivity which equates to lower usage of wood fuel, the pots are widely used. The aim of this article is to describe current insights and emerging evidence of health risks associated with artisanal pot making and usage. This thriving industry, particularly in poorly resourced communities, has multifaceted occupational, environmental and human health impacts. Given the complexity, innovative solutions need to be prioritized, evaluated and scaled up in relevant settings.

Environmental health practitioners potentially play a key role in helping communities adapt to climate change.

BACKGROUND: Vulnerable population groups in South Africa, especially those living in poverty, young children, women, the elderly and people with pre-existing diseases, are susceptible to new or exacerbated health threats resulting from climate change. Environmental Health Practitioners (EHPs) can play an important role in helping communities adapt to climate change health impacts, however, effective coordination of this requires further understanding of their roles in implementing climate change-related adaptation actions in communities. METHODS: A cross-sectional survey using convenience sampling was undertaken at the January 2017 conference for EHPs hosted by the South African Institute of Environmental Health in Cape Town. All EHPs who attended the conference were invited to complete a study questionnaire that requested information on participant demographics, as well as climate change related-knowledge, practices and perceptions. RESULTS: Majority of participating EHPs (n = 48; 72.8%) had received formal or informal training on climate change and health. Thirty-nine percent of EHPs indicated that they had a climate change and health-related committee / working group in their department, a policy or strategy (41.0%) and budget allocated for climate change and health-related work (51.5%). A total of 33.3% had participated in climate change-related projects. Majority (62.2%) of EHPs believed that they should play a supportive role in addressing climate change while 37.8% believed that EHPs should play a leading role. CONCLUSIONS: Recognising the need for raising awareness about climate change adaptation as well as implementing appropriate interventions to combat climate-related ill health effects, especially among vulnerable groups, EHPs are well-placed to adopt significant roles in helping communities to adapt to climate change.

Copper sulphate use in South African traditional medicine.

Copper (Cu) is an essential element to humans; however, exposure to elevated concentrations through occupational hazard and/or environmental means may be detrimental. This paper provides results of a cross-sectional study aimed to determine the prevalence of copper sulphate (CuSO4) use in South African traditional medicine by traditional health practitioners (THPs) and details the use thereof. A total of 201 THPs were enrolled from two main municipal areas of KwaZulu-Natal (South Africa). Information on demographic characteristics of THPs, reasons for using or not using CuSO4 as well as administration methods and age groups of recipients were collected. Of the 201 THPs interviewed, 145 (72 %) use CuSO4 for healing purposes. The use of CuSO4 was strongly associated with gender (p = 0.009) where the proportion of CuSO4 users was higher for female than male THPs. CuSO4 was reportedly administered to individuals of all ages, including infants and children. The main routes of administration were enema (n = 110; 76 %), oral (n = 40; 28 %) and use in bath (n = 40; 28 %). The reasons cited for use are diverse and included skin rashes (n = 43; 30 %), aches, pains and swelling (n = 38; 28 %) as well as sexually transmitted diseases (n = 28; 19 %). This study identified a high prevalence of THPs using CuSO4 for healing purposes. These findings support the need to regulate South African traditional medicine to safeguard the user.

Predictors of perceived male partner concurrency among women at risk for HIV and STI acquisition in Durban, South Africa.

BACKGROUND: Women in sub-Saharan Africa continue to be at greater risk for HIV acquisition than men. Concurrency, viz. multiple sexual partnerships that overlap over time, has been studied as a possible risk factor for HIV transmission. The aim of this study was to identify predictors of perceived male partner concurrency among sexually active, HIV negative women. METHODS: Socio-demographic and behavioural data from women enrolled in a biomedical HIV prevention clinical trial were assessed in relation to perceived male partner concurrency using the Chi squared test. Univariate and multivariate logistic regression was performed to assess the independent predictors of perceived male partner concurrency. Kaplan-Meier survival estimates were obtained for HIV and STI incidence in relation to male partner concurrency. A Cox Proportional Hazards model was used to assess the association between perceived male partner concurrency and HIV and STI incidence. RESULTS: The results revealed that 29 % of women reported their male partners to be in concurrent sexual relationships, 22 % reported partners that were not engaging in concurrency, whilst 49 % reported not knowing their partners concurrency status. Older women, having never married, experiencing economic abuse, and women reporting individual concurrency, were found to be significant predictors of perceived male partner concurrency in the studied population. Perceived male partner concurrency was not found to be a significantly associated with incident HIV and STI infections in this analysis. CONCLUSIONS: The study provides insight into predictors of perceived male partner concurrency among women at high risk for STI and HIV acquisition. These results may inform the design of behavioural and biomedical interventions, to address the role of multiple sexual partnerships in HIV prevention.

Metallic mercury use by South African traditional health practitioners: perceptions and practices.

BACKGROUND: Mercury is a toxic metal however its use in traditional healthcare systems remains widespread. The aim of this study was to determine the prevalence of mercury use by South African Traditional Health Practitioners (THP) and to document reasons for use and administration methods. METHODS: A cross-sectional study design was employed. A total of 201 THPs were enrolled from two main metropolitan areas of KwaZulu-Natal (South Africa), and 198 were included in the final analysis. Information on demographic characteristics, reasons for using or not using mercury as well as mercury administration methods were collected. RESULTS: Of the 198 THPs, 78 (39%) used mercury for healing purposes and 74 (95%) of the mercury users stated that they were taught to use it by another THP. The two main routes of administration were oral and sub-cutaneous implantations (ukugcaba) at 85% (n = 66) and 59% (n = 46), respectively. The most common responses for mercury administration were for child birth (n = 70; 90%) and protection against guns (n = 39; 50%). CONCLUSION: This is the first study to describe the prevalence and practice of mercury use in South African traditional medicine. Socio-cultural mercury use is a potential source of exposure to both THPs and their patients. In light of such findings, public education messages and regulatory measures need to be effected.

Relations between personal exposure to elevated concentrations of arsenic in water and soil and blood arsenic levels amongst people living in rural areas in Limpopo, South Africa.

Exposure to arsenic even at low levels can lead to adverse health outcomes, however, there is a paucity of research from South Africa in relation to human exposure to arsenic. We investigated long-term exposure of residents in Limpopo province, South Africa, in a cross-sectional study by analysing water, soil and blood arsenic concentrations from two arsenic-exposed (high and medium-low exposure) villages and one non-exposed (control) village. There were statistically significant differences in the distribution of arsenic in water, soil and blood amongst the three sites. The median drinking water arsenic concentration in the high-exposure village was 1.75 µg/L (range = 0.02 to 81.30 µg/L), 0.45 µg/L (range = 0.100 to 6.00 µg/L) in the medium- / low-exposure village and 0.15 µg/L (range = < limit of detection (LOD) to 29.30 µg/L) in the control site. The median soil arsenic concentration in the high-exposure village was 23.91 mg/kg (range = < LOD to 92.10 mg/kg) whilst arsenic concentrations were below the limit of detection in all soil samples collected from the medium-/low-exposure and control villages. In the high-exposure village, the median blood arsenic concentration was 1.6 µg/L (range = 0.7 to 4.2 µg/L); 0.90 µg/L (range = < LOD to 2.5 µg/L) in the medium-/low-exposure village and 0.6 µg/L (range = < LOD to 3.3 µg/L) in the control village. Significant percentages of drinking water, soil and blood samples from the exposed sites were above the internationally recommended guidelines (namely, 10 µg/L, 20 mg/kg and 1 µg/L, respectively). Majority of participants (86%) relied on borehole water for drinking and there was a significant positive correlation between arsenic in blood and borehole water (p-value = 0.031). There was also a statistically significant correlation between arsenic concentrations in participants' blood and soil samples collected from gardens (p-value = 0.051). Univariate quantile regression found that blood arsenic concentrations increased by 0.034 µg/L (95% CI = 0.02-0.05) for each one unit increase in water arsenic concentrations (p < 0.001). After adjusting for age, water source and homegrown vegetable consumption in multivariate quantile regression, participants from the high-exposure site had significantly higher blood concentrations than those in the control site (coefficient: 1.00; 95% CI = 0.25-1.74; p-value = 0.009) demonstrating that blood arsenic is a good biomarker of arsenic exposure. Our findings also provide new evidence for South Africa on the association between drinking water and arsenic exposure, emphasising the need for the provision of potable water for human consumption in areas with high environmental arsenic concentrations.

Environmental exposure to uranium in a population living in close proximity to gold mine tailings in South Africa.

BACKGROUND: Gold mining activities in South Africa resulted in contamination of residential environment with uranium-rich wastes from mine tailings. Health of the people living around the mine tailings could be affected by uranium exposure due to its hazardous chemotoxic and radiological properties. METHODS: We conducted a cross-sectional study to assess i) uranium (U) concentrations in individual hair samples of children and adults living in close proximity to mine tailings in Northeast- Soweto in Johannesburg, South Africa, and ii) the association between U concentrations in hair and various factors, including zone of residence, socio-demographic and housing characteristics. Sampling sites were divided into three zones based on the distance between a dwelling and a cluster of mine tailings (zone 1: <= 500 m, zone 2: 2-3 km away, zone 3: 4-5 km away). U concentrations in hair samples were measured using inductively coupled plasma mass spectrometry. To test the association between U concentrations and selected factors we used robust regression models with log-transformed U concentrations. RESULTS: Among 128 subjects with available U measurements, 63 (49%) were children (ages 7-15 years) of which 38 were girls, the remaining 65 (51%) were adult females. Mean (median) U concentration in hair samples was 143 (92) µg/kg. In the mutually adjusted analyses, only an inverse association between age and U concentration in hair remained statistically significant, with geometric mean in children being 2.1 times higher compared to adults (P < 0.001). There was no evidence of an association between zones and U concentration (P = 0.42). CONCLUSIONS: There was little evidence of association between U concentration in hair and distance from the mine tailings within the 5 km range, but overall concentrations were elevated compared to general population samples in other parts of the world. Children had statistically significantly higher geometric mean of uranium concentration in hair compared to adults. The results are important for improvement of mining waste policies and implementation of health monitoring and protective measures in populations at risk. ARTICLE CATEGORY: Research Article.

GRADE GUIDANCE 38: Updated guidance for rating up certainty of evidence due to a dose-response gradient.

INTRODUCTION: This updated guidance from the Grading of Recommendations Assessment, Development, and Evaluation addresses rating up certainty of evidence due to a dose-response gradient (DRG) observed in synthesis of intervention and exposure studies. STUDY DESIGN AND SETTING: This guidance was developed using iterative discussions and consensus in multiple meetings and was presented to attendees of the Grading of Recommendations Assessment, Development, and Evaluation Working Group meeting for feedback in November 2022 and for final approval in May 2023. RESULTS: The guidance consists of two steps. The first is to determine whether the DRG is credible. We describe five items for assessing credibility: a) is DRG identified using a proper analytical approach; b) is confounding the cause of the DRG; c) is there serious concern about ecological bias; d) is the DRG consistent across studies; and e) is there indirect evidence supporting the DRG. The first two of these items are the most critical. If the DRG was judged to be credible, then the second step is to apply the DRG domain and consider rating up, but only by one level due to the concern about residual confounding. CONCLUSION: Systematic review authors should only rate up certainty in evidence when a DRG is deemed credible.

Using Wastewater Surveillance to Compare COVID-19 Outbreaks during the Easter Holidays over a 2-Year Period in Cape Town, South Africa.

Wastewater surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has shown to be an important approach to determine early outbreaks of infections. Wastewater-based epidemiology (WBE) is regarded as a complementary tool for monitoring SARS-CoV-2 trends in communities. In this study, the changes in the SARS-CoV-2 RNA levels in wastewater during Easter holidays in 2021 and 2022 in the City of Cape Town were monitored over nine weeks. Our findings showed a statistically significant difference in the SARS-CoV-2 RNA viral load between the study weeks over the Easter period in 2021 and 2022, except for study week 1 and 4. During the Easter week, 52% of the wastewater treatment plants moved from the lower (low viral RNA) category in 2021 to the higher (medium to very high viral RNA) categories in 2022. As a result, the median SARS-CoV-2 viral loads where higher during the Easter week in 2022 than Easter week in 2021 (p = 0.0052). Mixed-effects model showed an association between the SARS-CoV-2 RNA viral loads and Easter week over the Easter period in 2021 only (p < 0.01). The study highlights the potential of WBE to track outbreaks during the holiday period.

Molecular epidemiology of SARS-CoV-2 in Northern South Africa: wastewater surveillance from January 2021 to May 2022.

Introduction: Wastewater-based genomic surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) provides a comprehensive approach to characterize evolutionary patterns and distribution of viral types in a population. This study documents the molecular epidemiology of SARS-CoV-2, in Northern South Africa, from January 2021 to May 2022. Methodology: A total of 487 wastewater samples were collected from the influent of eight wastewater treatment facilities and tested for SARS-CoV-2 RNA using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). SARS-CoV-2 positive samples with genome copies/mL ≥1,500 were subjected to allele-specific genotyping (ASG) targeting the Spike protein; 75 SARS-CoV-2 positive samples were subjected to whole genome sequencing (WGS) on the ATOPlex platform. Variants of concern (VoC) and lineages were assigned using the Nextclade and PangoLIN Software. Concordance for VoC between ASG and WGS analyses was determined. Sequence relationship was determined by phylogenetic analysis. Results: Seventy-five percent (365/487) of the influent samples were positive for SARS-CoV-2 RNA. Delta and Omicron VoC were more predominant at a prevalence of 45 and 32%, respectively, and they were detected as early as January and February 2021, while Beta VoC was least detected at a prevalence of 5%. A total of 11/60 (18%) sequences were assigned lineages and clades only, but not a specific VoC name. Phylogenetic analysis was used to investigate the relationship of these sequences to other study sequences, and further characterize them. Concordance in variant assignment between ASG and WGS was seen in 51.2% of the study sequences. There was more intra-variant diversity among Beta VoC sequences; mutation E484K was absent. Three previously undescribed mutations (A361S, V327I, D427Y) were seen in Delta VoC. Discussion and Conclusion: The detection of Delta and Omicron VoCs in study sites earlier in the outbreak than has been reported in other regions of South Africa highlights the importance of population-based approaches over individual sample-based approaches in genomic surveillance. Inclusion of non-Spike protein targets could improve the specificity of ASG, since all VoCs share similar Spike protein mutations. Finally, continuous molecular epidemiology with the application of sensitive technologies such as next generation sequencing (NGS) is necessary for the documentation of mutations whose implications when further investigated could enhance diagnostics, and vaccine development efforts.

Elevated soil and blood lead levels with increasing residential proximity to a mine tailings facility in Soweto, South Africa.

Mining has long been associated with the release of a range of toxic metals including lead, elevated levels of which have been found in land surrounding mine dumps as far afield as Spain, India, Macedonia and Nigeria. Mining has been a key pillar of economic development in South Africa for around a century and a half, and has left a legacy of major environmental contamination, with the poorest experiencing the highest burden of exposure. The current study was undertaken to ascertain the concentrations of lead in soil and in the blood of adults and children residing at increasing distances from a cluster of large tailings facilities (MTFs) in greater Johannesburg, South Africa. Through a cross-sectional survey data on household characteristics were collected through a questionnaire survey, and supplemented with samples of soil from household gardens, together with blood samples from child-adult pairs from all households included in the study. Soil lead concentrations decreased significantly (median = 35.7 mg/kg closest to the mine tailings facility (MTF) and 8.6 mg/kg at the furthest point in the study site) with increasing distance from the MTF. Blood lead levels were highest in both adults (median = 3.0 µg/dL) and children (median = 4.0 µg/dL) who lived closest (≤500 m) to the MTF, and lowest (1.4 µg/dL in adults and 2.5 µg/dL in children) in those who lived furthest away (4-5 km). The study findings point to a need for greater emphasis on the precautionary principle in environmental health and for health impact assessments to inform decisions on planning, especially with regard to the location of human settlements relative to major, polluting development initiatives.

Heavy Metal Contamination of Soil in Preschool Facilities around Industrial Operations, Kuils River, Cape Town (South Africa).

The contamination of soil by heavy metals is a potential health risk, especially among susceptible populations. The aim of this study was to measure the levels of heavy metals, identify the contamination levels and possible sources of heavy metals, and evaluate the health risk caused by heavy metals to the children living in Kuils River. Composite samples of soil were collected at 34 preschools. A portable X-ray fluorescence spectrometer was used to measure the levels of metals. Contamination levels were evaluated using a geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (CF) and pollution load index (PLI). The spatial distribution of the Igeo contamination levels was assessed using ArcGIS. Sources of heavy metals and the correlation among metals were assessed using factor analysis and Pearson correlation, respectively. The measured concentrations of metals were used to estimate the health risk for children. The average levels of the metals were 16, 4469, 137, 30, 176, 1547 and 232 mg/kg for arsenic (As), iron (Fe), manganese (Mn), lead (Pb), strontium (Sr), titanium (Ti) and zinc (Zn), respectively. According to Igeo, EF, CF and PLI contamination exist in the study area. The health index (HI) for non-carcinogenic effects showed the ingestion route as the main contributor to the total risk, with the accumulative carcinogenic risk exceeding the maximum acceptable level. To protect the affected communities, and children in particular, this study provides evidence of the need for action, including the institution of mandatory buffer zones between pollutant-generating activities and human settlements.