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Despite the fact that several cases of unsafe pesticide use among farmers in different parts of Africa have been documented, there is limited evidence regarding which specific interventions are effective in reducing pesticide exposure and associated risks to human health and ecology. The overall goal of the African Pesticide Intervention Project (APsent) study is to better understand ongoing research and public health activities related to interventions in Africa through the implementation of suitable target-specific situations or use contexts. A systematic review of the scientific literature on pesticide intervention studies with a focus on Africa was conducted. This was followed by a qualitative survey among stakeholders involved in pesticide research or management in the African region to learn about barriers to and promoters of successful interventions. The project was concluded with an international workshop in November 2021, where a broad range of topics relevant to occupational and environmental health risks were discussed such as acute poisoning, street pesticides, switching to alternatives, or disposal of empty pesticide containers. Key areas of improvement identified were training on pesticide usage techniques, research on the effectiveness of interventions targeted at exposure reduction and/or behavioral changes, awareness raising, implementation of adequate policies, and enforcement of regulations and processes.

There is a paucity of air quality data in sub-Saharan African countries to inform science driven air quality management and epidemiological studies. We investigated the use of available remote-sensing aerosol optical depth (AOD) data to develop spatially and temporally resolved models to predict daily particulate matter (PM

There is a paucity of air quality data in sub-Saharan African countries to inform science driven air quality management and epidemiological studies. We investigated the use of available remote-sensing aerosol optical depth (AOD) data to develop spatially and temporally resolved models to predict daily particulate matter (PM10) concentrations across four provinces of South Africa (Gauteng, Mpumalanga, KwaZulu-Natal and Western Cape) for the year 2016 in a two-staged approach. In stage 1, a Random Forest (RF) model was used to impute Multiangle Implementation of Atmospheric Correction AOD data for days where it was missing. In stage 2, the machine learner algorithms RF, Gradient Boosting and Support Vector Regression were used to model the relationship between ground-monitored PM10 data, AOD and other spatial and temporal predictors. These were subsequently combined in an ensemble model to predict daily PM10 concentrations at 1 km x 1 km spatial resolution across the four provinces. An out-of-bag R(2) of 0.96 was achieved for the first stage model. The stage 2 cross-validated (CV) ensemble model captured 0.84 variability in ground-monitored PM10 with a spatial CV R(2) of 0.48 and temporal CV R(2) of 0.80. The stage 2 model indicated an optimal performance of the daily predictions when aggregated to monthly and annual means. Our results suggest that a combination of remote sensing data, chemical transport model estimates and other spatiotemporal predictors has the potential to improve air quality exposure data in South Africa's major industrial provinces. In particular, the use of a combined ensemble approach was found to be useful for this area with limited availability of air pollution ground monitoring data.

International audience; For decades pesticides have been used in agriculture, however, the occurrence of legacy organochlorine pesticides (OCPs) and current-use pesticides (CUPs) is poorly understood in Africa. This study investigates air concentrations of OCPs and CUPs in three South African agricultural areas, their spatial/seasonal variations and mixture profiles.Between 2017 and 2018, 54 polyurethane foam-disks passive air-samplers (PUF-PAS) were positioned in three agricultural areas of the Western Cape, producing mainly apples, table grapes and wheat. Within areas, 25 CUPs were measured at two sites (farm and village), and 27 OCPs at one site (farm). Kruskal-Wallis tests investigated area differences in OCPs concentrations, and linear mixed-effect models studied differences in CUPs concentrations between areas, sites and sampling rounds.In total, 20 OCPs and 16 CUPs were detected. A median of 16 OCPs and 10 CUPs were detected per sample, making a total of 11 OCPs and 24 CUPs combinations. Eight OCPs (trans-chlordane, o,p’-/p,p’-dichlorodiphenyldichloroethylene (DDE)/dichlorodiphenyltrichloroethane (DDT), endosulfan sulfate, γ-hexachlorocyclohexane and mirex) and two CUPs (carbaryl and chlorpyrifos) were quantified in all samples. p,p’-DDE (median 0.14 ng/m3) and chlorpyrifos (median 0.70 ng/m3) showed the highest concentrations throughout the study. Several OCPs and CUPs showed different concentrations between areas and seasons, although CUPs concentrations did not differ between sites. OCPs ratios suggest ongoing chlordane use in the region, while DDT and endosulfan contamination result from past-use.Our study revealed spatial and seasonal variations of different OCPs and CUPs combinations detected in air. Further studies are needed to investigate the potential cumulative or synergistic risks of the detected pesticides.

Concerns about the possible negative impacts of current use pesticides (CUPs) for both the environment and human health have increased worldwide. However, the knowledge on the occurrence of CUPs in soil and air and the related human exposure in Africa is limited. This study investigated the presence of 30 CUPs in soil and air at two distinct agricultural sites in South Africa and estimated the human exposure and related risks to rural residents via soil ingestion and inhalation (using hazard quotients, hazard index and relative potency factors). We collected 12 soil and 14 air samples over seven days during the main pesticide application season in 2018. All samples were extracted, purified and analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry. In soils, nine CUPs were found, with chlorpyrifos, carbaryl and tebuconazole having the highest concentrations (up to 63.6, 1.10 and 0.212 ng g(-1), respectively). In air, 16 CUPs were found, with carbaryl, tebuconazole and terbuthylazine having the highest levels (up to 25.0, 22.2 and 1.94 pg m(-3), respectively). Spatial differences were observed between the two sites for seven CUPs in air and two in soils. A large dominance towards the particulate phase was found for almost all CUPs, which could be related to mass transport kinetics limitations (non-equilibrium) following pesticide application. The estimated daily intake via soil ingestion and inhalation of individual pesticides ranged from 0.126 fg kg(-1) day(-1) (isoproturon) to 14.7 ng kg(-1) day(-1) (chlorpyrifos). Except for chlorpyrifos, soil ingestion generally represented a minor exposure pathway compared to inhalation (i.e.

Background Maternal substance use and its long-term effect on the neurocognitive functions of children is a global public health issue. Despite an increase in substance use in rural areas of low to middle-income countries, research is limited in these populations. Objective We have therefore explored the effect of maternal drinking and smoking behaviors on the neurocognitive functioning of rural school children. Method A cross-sectional analysis on the determinants of current, past and gestational maternal alcohol use and gestational smoking on child neurocognitive functions was conducted on school-children (N = 482), embedded within the child health agricultural cohort (CapSA) study across seven schools in rural Western Cape, South Africa. Standardised neurocognitive assessment tools included the Cambridge Automated Neuropsychological Battery (CANTAB) and the KIDSCREEN-10 to measure health-related quality of life via a child questionnaire. Maternal smoking and drinking behaviour were captured using a parent/guardian questionnaire. Results Of the 482 parents/guardians who completed the survey, 29 % reported current drinking 27 % reported past drinking and 10 % reported maternal gestational drinking, while 31 % reported gestational smoking. Significant associations were observed between past and current maternal drinking and child’s reduced rapid visual processing accuracy in attention [β:-0.03; 95 % confidence interval (CI): -0.05;-0.004] and between maternal drinking during pregnancy and reduced child’s spatial working memory (β: -0.59; CI: -1.02; -0.15). Heavy (>5 cigarettes per day) gestational smoking was associated with lowered child’s learning in memory (β:-1.69; 95 % CI: -3.05; -0.33) and lower health-related quality of life (β: -3.41; CI: -6.64; -0.17). The odds of a child repeating a grade were 1.69 (CI: 2.81−1.02) for those exposed to maternal gestational smoking and 1.68 (CI: 3.31−0.85) for those exposed to maternal gestational drinking compared to those who were not exposed. Conclusion The consistent negative associations across all four maternal substance use proxies, six neurocognitive health outcomes and one health symptom is suggestive of adverse health effects, warranting longitudinal follow-up. Health policies to eliminate gestational substance use are recommended.

Objective Children and adolescents living in agricultural areas are likely to be exposed to mixtures of pesticides during their daily activities, which may impair their neurodevelopment. We investigated various such activities in relation to headache severity and neurodevelopment of school-children living in rural agricultural areas in the Western Cape of South Africa. Method We used baseline date from 1001 school-children of the Child Health Agricultural Pesticide Cohort Study in South Africa (CapSA) aged 9–16 from seven schools and three agriculture areas in the Western Cape. Questionnaires were administrated to assess activities related to pesticide exposure and health symptoms addressing four types of activities: 1) child farm activities related to pesticide handling, 2) eating crops directly from the field, 3) contact with surface water around the field, and 4) seen and smelt pesticide spraying activities. Neurocognitive performance across three domains of attention, memory and processing speed were assessed by means of an iPad-based cognitive assessment tool, Cambridge Automated NeuroPsychological Battery (CANTAB). Headache severity was enquired using a standard Headache Impact Test (HIT-6) tool. Cross-sectional regression analysis was performed. Results About 50% of the cohort report to have ever been engaged in activities related to pesticide exposure including farm activities, eating crops directly from the field and leisure activities. Headache severity score was consistently increased in relation to pesticide-related farm activities (score increase of 1.99; 95% CI: 0.86, 3.12), eating crops (1.52; 0.41, 2.67) and leisure activities of playing, swimming or bathing in nearby water (1.25; 0.18, 2.33). For neurocognitive outcomes, an overall negative trend with pesticide exposure-related activities was observed. Among others, involvement in pesticide-related farm activities was associated with a lower multi-tasking accuracy score (−2.74; −5.19, −0.29), while lower strategy in spatial working memory (−0.29; −0.56; −0.03) and lower paired associated learning (−0.88; −1.60, −0.17) was observed for those who pick crops off the field compared to those who do not pick crops off the field. Eating fruits directly from the vineyard or orchard was associated with a lower motor screening speed (−0.06; −0.11, −0.01) and lower rapid visual processing accuracy score (−0.02; −0.03, 0.00). Conclusions Children who indicate activities related to pesticide exposure may be at higher risk for developing headaches and lower cognitive performance in the domains of attention, memory and processing speed. However, self-reported data and cross-sectional design are a limitation. Future research in CapSA will consider pesticide exposure estimations via urinary biomarkers and longitudinal assessment of cognitive functions.

Particulate matter less than or equal to 10 μm in aerodynamic diameter (PM10 µg/m3) is a priority air pollutant and one of the most widely monitored ambient air pollutants in South Africa. This study analyzed PM10 from monitoring 44 sites across four provinces of South Africa (Gauteng, Mpumalanga, Western Cape and KwaZulu-Natal) and aimed to present spatial and temporal variation in the PM10 concentration across the provinces. In addition, potential influencing factors of PM10 variations around the three site categories (Residential, Industrial and Traffic) were explored. The spatial trend in daily PM10 concentration variation shows PM10 concentration can be 5.7 times higher than the revised 2021 World Health Organization annual PM10 air quality guideline of 15 µg/m3 in Gauteng province during the winter season. Temporally, the highest weekly PM10 concentrations of 51.4 µg/m3, 46.8 µg/m3, 29.1 µg/m3 and 25.1 µg/m3 at Gauteng, Mpumalanga, KwaZulu-Natal and Western Cape Province were recorded during the weekdays. The study results suggest a decrease in the change of annual PM10 levels at sites in Gauteng and Mpumalanga Provinces. An increased change in annual PM10 levels was reported at most sites in Western Cape and KwaZulu-Natal.

Background: There is limited data on the association between diarrhoea among children aged under five years (U5D) and water use, sanitation, hygiene, and socio-economics factors in low-income communities. The study investigated U5D and the associated risk factors in the Zeekoe catchment in Cape Town, South Africa. Methods: A cross-sectional study was conducted in 707 households in six informal settlements (IS) two formal settlements (FS) (March–June 2017). Results: Most IS households used public taps (74.4%) and shared toilets (93.0%), while FS households used piped water on premises (89.6%) and private toilets (98.3%). IS respondents had higher average hand-washing scores than those of FS (0.04 vs. −0.14, p = 0.02). The overall U5D prevalence was 15.3% (range: 8.6%–24.2%) and was higher in FS than in IS (21.2% vs. 13.4%, respectively, p = 0.01). Water storage &gt, 12 h was associated with increasing U5D (OR = 1.88, 95% CI 1.00–3.55, p = 0.05). Water treatment (OR = 0.57, 95%CI 0.34–0.97, p = 0.04), good hand-washing practices (OR = 0.59, 95%CI 0.42–0.82, p = 0.002) and Hepatitis A vaccination (OR = 0.51, 95%CI 0.28–0.9, p = 0.02) had significant preventing effects on U5D. Conclusions: The study highlights that good hygiene practice is a key intervention against U5D in informal settlements. The promotion of hand-washing, proper water storage, and hygienic breastfeeding is highly recommended.

Few studies have investigated the relationship between ambient air pollution and cardiorespiratory outcomes in Africa. A cross-sectional study comprising of 572 adults from four informal settlements in the Western Cape, South Africa was conducted. Participants completed a questionnaire adapted from the European Community Respiratory Health Survey, and the National Health and Nutrition Examination Survey questionnaire. Exposure estimates were previously modelled using Land-Use Regression for Particulate Matter (PM2.5) and Nitrogen Dioxide (NO2) at participants’ homes. The median age of the participants was 40.7 years, and 88.5% were female. The median annual NO2 level was 19.7 µg/m3 (interquartile range [IQR: 9.6–23.7]) and the median annual PM2.5 level was 9.7 µg/m3 (IQR: 7.3–12.4). Logistic regression analysis was used to assess associations between outcome variables and air pollutants. An interquartile range increase of 5.12 µg/m3 in PM2.5 was significantly associated with an increased prevalence of self-reported chest-pain, [Odds ratio: 1.38 (95% CI: 1.06–1.80)], adjusting for NO2, and other covariates. The study found preliminary circumstantial evidence of an association between annual ambient PM2.5 exposure and self-reported chest-pain (a crude proxy of angina-related pain), even at levels below the South African National Ambient Air Quality Standards.

Droughts are associated with several health effects and Africa is uniquely vulnerable. Despite this, there has been no previous review of the literature on the health effects of drought in Africa. This study systematically reviewed the epidemiological research on the association between drought and adverse health effects in Africa (2012-2019). A total of fifteen articles were included in the review after screening 1922 published (peer-reviewed) and unpublished articles. These studies were all conducted in 9 Sub-Saharan African countries. The drought-related health effects identified were on adverse nutritional health (n = 8) including malnutrition resulting in reduced body size and wasting, stunting and underweight, mortality from food insecurity, anaemia from food insecurity and nutrition-related disability from food insecurity; drought and diseases due to microbial contamination of water (n = 6) including cholera, diarrhoeal diseases, scabies, vector-borne diseases and malaria-related mortality; and drought and health behaviours (n = 1) including HIV prevention and care behaviours. The study found limited evidence of a high prevalence of malnutrition, an increased prevalence of anaemia, cholera, scabies, dengue and an increased incidence in child disabilities during periods of drought. Additionally, there was limited evidence on improved child nutritional health with improved water and sanitation access, and an increased prevalence of child wasting, stunting and underweight in drought-prone areas. No evidence of drought on other health outcomes was found. However, all the studies had more than one limitation including weak study design, a lack of comparison to a drought period, uncertainty on the onset and end of drought, lack of control for confounding, presence of contextual factors, weak outcome and/or exposure measure, small sample size and lack of generalizability. This review found weak evidence for all health outcomes measured but highlights key areas for further research and contextual factors which need to be considered for interventions.

Evidence on the relationship between lifestyle, socio-economic factors and pesticide exposure and urinary concentrations of organophosphate (OP) pesticide metabolites among children is generally incomplete. This study investigated the relationship between socio-economic factors and reported pesticide exposures and the sum of three urinary concentrations of dialkyl phosphate metabolites (DAP) among boys living in the rural areas of the Western Cape, South Africa. Data was collected during a cross-sectional study of 183 boys from three agricultural intense areas. Measurements included a questionnaire on socio-economic and pesticide exposures and urinary DAP concentrations. Most boys (70%) lived on farms with a median age of 12 years (range: 5.0–19.5 years). Children aged >14 years had lower DAP urine concentrations (median = 39.9 ng/ml; β = −68.1 ng/ml; 95% CI: −136.8, 0.6) than children aged 9 years and younger (median = 107.0 ng/ml). DAP concentrations also varied significantly with area, with concentrations in the grape farming area, Hex River Valley (median = 61.8 ng/ml; β = −52.1; 95% CI: −97.9, −6.3 ng/ml) and the wheat farming area, Piketberg (median = 72.4 ng/ml; β = −54.2; 95% CI: 98.8, −9.7 ng/ml) lower than those in the pome farming area, Grabouw (median = 79.9 ng/ml). Other weaker and non-significant associations with increased DAP levels were found with increased household income, member of household working with pesticides, living on a farm, drinking water from an open water source and eating crops from the vineyard and or garden. The study found younger age and living in and around apple and grape farms to be associated with increased urinary DAP concentrations. Additionally, there were other pesticide exposures and socio-economic and lifestyle factors that were weakly associated with elevated urinary DAP levels requiring further study. The study provided more evidence on factors associated to urinary DAP concentrations especially in developing country settings.

This study presents a novel sample preparation method for the determination of both specific and non-specific pesticide metabolites in human urine samples. The method combines a deconjugation step with QuEChERS-based method and solid-phase extraction. In total, 15 pesticide metabolites (diethyl phosphate; diethyl thiophosphate; dimethyl phosphate; diethyl thiophosphate; 2,4-dichlorophenoxyacetic acid; 3-phenoxybenzoic acid; 4-fluoro-3-phenoxybenzoic acid; coumaphos; diethyl dithiophosphate; malathion dicarboxylic acid; p-nitrophenol; cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid; 3,5,6-trichloro-2-pyridinol; N,N-diethyl-3-methylbenzamid and 2-isopropyl-4-methyl-6-hydroxypyrimidine) were separated using liquid chromatography coupled to a mass spectrometer and isotope dilution method for quantitation. The method was validated using recovery tests with recoveries generally ranging from 80 to 120%. Additionally, 20 urine samples collected from South African children were analysed using the presented method. The median levels of pesticide metabolites found in the urine samples ranged from not detected (N,N-diethyl-3-methylbenzamid) to 22.36 µg/g creatinine (dimethyl phosphate). The novel method developed in this study is sensitive, selective, robust and reproducible while also conserving the amount of sample, chemicals, material and time required. Due to the low limits of detection obtained for individual pesticide metabolites, the method is capable of quantifying trace levels of pesticide metabolites in urine, which thus makes it an ideal tool for biomonitoring studies.

International audience; Purpose: Respiratory hazards of farming have been identified for centuries, with little focus on gender differences. We used data from the AGRICOH consortium, a collective of prospective cohorts of agricultural workers, to assess respiratory disease prevalence among adults in 18 cohorts representing over 200,000 farmers, farm workers, and their spouses from six continents.Methods: Cohorts collected data between 1992 and 2016 and ranged in size from 200 to >128,000 individuals; 44% of participants were female. Farming practices varied from subsistence farming to large-scale industrial agriculture. All cohorts provided respiratory outcome information for their cohort based on their study definitions. The majority of outcomes were based on self-report using standard respiratory questionnaires; the greatest variability in assessment methods was associated with chronic obstructive pulmonary disease (COPD).Results: For all three respiratory symptoms (cough, phlegm, and wheeze), the median prevalence in men was higher than in women, with the greatest difference for phlegm (17% vs. 10%). For asthma, women had a higher prevalence (7.8% vs 6.5%), with the difference associated with allergic asthma. The relative proportion of allergic asthma varied among cohorts. In two of eight cohorts for women and two of seven cohorts for men, allergic asthma was more common than non-allergic asthma.Conclusions: These findings indicate that respiratory outcomes are common among farmers around the world despite differences in agricultural production. As women in the general population are at higher risk of asthma, exploring gender differences in occupational studies is critical for a deeper understanding of respiratory disease among agricultural workers.

Increasing use of current-use pesticides (CUPs) in Africa raises environmental and public health concerns. But there is a large uncertainty about their occurrence and the composition of pesticide mixtures on this continent. This paper investigates the presence of 27 CUPs in air across 20 sampling sites in Africa. 166 passive air samples, consisting of polyurethane foam (PUF), were collected in 12 African countries between 2010 and 2018. Samples were extracted with methanol and analyzed via high-performance liquid chromatography coupled with tandem mass spectrometry. The detection frequencies of CUPs per site were compared to land use patterns and sampling years, while their similarities were assessed using hierarchical cluster analysis. Overall, 24 CUPs were detected at least once. In 93% of all samples, at least one CUP was detected, while 78% of the samples had mixtures of two or more CUPs (median 3, interquartile range 5). Atrazine and chlorpyrifos were detected in 19 out of 20 sampling sites. Carbaryl, metazachlor, simazine, tebuconazole and terbuthylazine had the highest detection frequencies at sampling sites dominated by croplands. Across all the sampling years, 16 CUPs were present. Seven CUPs were newly detected from 2016 onwards (azinfos-methyl, dimetachlor, chlorsulfuron, chlortoluron, isoproturon, prochloraz and pyrazon), while metamitron was only present before 2012. Sites within a radius of about 200 km showed similarities in detected CUP mixtures across all samples. Our results show the presence of CUP mixtures across multiple agricultural and urban locations in Africa which requires further investigation of related environmental and human health risks.

Global sperm counts have declined in recent decades, coinciding with the proliferation of endocrine-disrupting chemicals, of which pesticides are some of the most common. Previous systematic reviews of epidemiologic studies published between 1991 through 2013 have reported associations between environmental and occupational pesticide exposure and reduced sperm quality, particularly associations with reduced sperm concentration. This systematic review used the Navigation Guide to critically evaluate the current body of evidence examining sperm quality and pesticide exposure in epidemiological studies. PubMed, Scopus, and Web of Science databases were searched for all English-language articles published after September 2012 until August 2021. Original observational studies that assessed human sperm quality parameters, defined as concentration, motility, morphology, and DNA integrity, and individual-level pesticide exposure were included. The risk of bias for each included study and the strength of evidence were evaluated using the Navigation Guide protocol. Nineteen studies assessing environmental or occupational pesticide exposure and sperm parameters were included. Eighteen studies were cross-sectional studies and one prospective cohort; sample sizes ranged from 42 to 2122 men from 14 different countries. Fifteen (79 %) studies found at least one significant association between pesticide exposure and reduced sperm quality. The overall risk of bias across studies was classified as low to moderate. The quality of evidence was determined to be moderate based on systematic evaluation criteria. There were consistent adverse associations between pesticide exposure and sperm motility (63 % of studies) and DNA integrity (80 % of studies). For sperm concentration and morphology, 42 % and 36 % of studies found significant negative associations, respectively. The strength of the body of evidence overall was rated as having sufficient evidence of toxicity. Regarding specific sperm endpoints, there was sufficient evidence that pesticides are toxic for sperm motility and DNA integrity; limited evidence of toxicity for sperm concentration; and inadequate evidence of toxicity for sperm morphology. The studies reviewed here showed consistent associations between pesticide exposure and diminished sperm parameters, particularly sperm motility and sperm DNA integrity. These findings are largely consistent with results of previous reviews, which have found significant negative associations between pesticide exposure and sperm quality in 13 of 20 (65 %) studies published between 1991 and 2008, and in 14 of 17 (82 %) studies published between 2008 and 2012. After thirty years of mounting evidence, actions are needed to reduce pesticide risks to testicular function and male fertility.

The health impact of indoor air pollution in informal settlement households has not been extensively studied in South Africa. This cross-sectional study investigated the association between asthma and common indoor exposures among schoolchildren from four informal settlements located in two municipalities in the Western Cape Province. A total of 590 children, aged 9-11 years, were recruited. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was administered to caregivers. Pulmonary function assessment included spirometry and fractional exhaled nitric oxide (FeNO). Phadiatop test for atopy was done. The prevalence of doctor-diagnosed asthma was 3.4% (n = 20) among whom only 50% were on treatment. The prevalence of current wheeze was 12.9%, and 17.6% had airway obstruction (FEV; 1; 35 ppb). In adjusted logistic regression models, dampness, visible mold growth, paraffin use for cooking, and passive smoking were associated with a twofold to threefold increased risk in upper and lower airway outcomes. The strongest association was that of visible mold growth with rhinitis (adjusted odds ratio-aOR 3.37, 95% CI: 1.69-6.71). Thus, there is a need for improved diagnosis of childhood asthma and Indoor Air Quality in informal settlement households.

Background: The aim of this study was to quantify RF-EMF exposure applying a tested protocol of RF-EMF exposure measurements using portable devices with a high sampling rate in different microenvironments of Switzerland, Ethiopia, Nepal, South Africa, Australia and the United States of America. Method: We used portable measurement devices for assessing RF-EMF exposure in 94 outdoor microenvironments and 18 public transport vehicles. The measurements were taken either by walking with a backpack with the devices at the height of the head and a distance of 20–30 cm from the body, or driving a car with the devices mounted on its roof, which was 170–180 cm above the ground. The measurements were taken for about 30 min while walking and about 15–20 min while driving in each microenvironment, with a sampling rate of once every 4 s (ExpoM-RF) and 5 s (EME Spy 201). Results: Mean total RF-EMF exposure in various outdoor microenvironments varied between 0.23 V/m (non-central residential area in Switzerland) and 1.85 V/m (university area in Australia), and across modes of public transport between 0.32 V/m (bus in rural area in Switzerland) and 0.86 V/m (Auto rickshaw in urban area in Nepal). For most outdoor areas the major exposure contribution was from mobile phone base stations. Otherwise broadcasting was dominant. Uplink from mobile phone handsets was generally very small, except in Swiss trains and some Swiss buses. Conclusions: This study demonstrates high RF-EMF variability between the 94 selected microenvironments from all over the world. Exposure levels tended to increase with increasing urbanity. In most microenvironments downlink from mobile phone base stations is the most relevant contributor. Keywords: Radio-frequency electromagnetic fields (RF-EMF), Microenvironment, Uplink, Downlink, Exposure assessment, Mobile phone handset, Mobile phone base station

Background Chemical hazard communication (e.g., label) is intended to alert users of the potential hazards of chemicals. Apart from the fact that hazard information needs to be understood, it is also important that it is recalled. Recall of hazard communication is critical when the written form of the information is not available at the time it is required. Methods A cross-sectional study investigating associations between the recall of chemical safety information on labels and safety data sheets among 402 participants including 315 workers (industry, transport and agriculture sectors) and 87 consumers in two provinces of South Africa was conducted. The recall of label information by participants was tested using two modules from a Hazard Communication Comprehensibility Testing (CT) Tool developed by the Centre for Environmental and Occupational Health Research at the University of Cape Town for the UN Institute for Training and Research (UNITAR). Results Respondents were predominantly male (67.7%), the median age was 37 years (IQR: 30–46 years) and less than half of the participants completed high school (47.5%). The skull and crossbones symbol was the label element most recalled, both freely without prompting (79.6%) and recognition after prompting (94.8%). Whereas, the first aid and treatment measures were the least frequently freely recalled (least frequent item 6.0%; most frequent item 29.9%). Multivariate analysis identified the following positive associations with the recall of all the label elements listing the strongest association: call appropriate services and industrial vs. consumer sector (OR = 2.4; 95% CI: 1.2; 4.6); call appropriate services and transport vs. consumer sector (OR = 4.4; 95% CI: 1.2; 16.0); flammable symbol and male vs. female gender (OR = 2.3; 95% CI: 1.0; 5.3); flammable symbol and home language English vs. African languages (OR = 6.6; 95% CI: 2.1; 21.2); any hazard statement and home language Afrikaans vs. African languages (OR = 14.0; 95% CI: 3.6; 54.2), any first aid statement and further education vs. none (OR = 3.3; 95% CI: 1.3; 8.0), correct chemical name and industry blue collar workers vs. non-industry blue collar workers (OR = 2.6; 95% CI: 1.1; 6.1), correct chemical name and non-industry white collar occupations vs. non-industry blue collar workers (OR = 2.7; 95% CI: 1.0; 7.1). Conclusion The study found a number of potential positive associations that influence recall of label elements of which some (e.g., sector, gender, occupation) suggest further research. Relevant policies in South Africa should ensure that the safety information on chemical labels is clearly visible to read and understandable which aids recall and the reduction in harmful chemical exposures.

BACKGROUND Previous epidemiological studies investigating modification of organophosphate (OP) neurotoxicity by xenobiotic metabolizing enzymes (XMEs) polymorphisms have produced inconsistent results. METHODS A cross-sectional study of 301 emerging farmers was conducted. Neurotoxicity testing included forward and backward recall, digit span, and vibration sensitivity testing. Questionnaire data included demography, potential confounders, and work history of pesticide exposures. Genomic DNA was analyzed from study participants for DNA variants of two glutathione S-transferases (GSTM1 and GSTT1), N-acetyltransferase 2 (NAT2), and Paraoxonase 1 (PON1). RESULTS There was evidence of OP pesticide neurotoxicity modification by rs1799931 (NAT2), rs662 (PON1), and the null allele of GSTM1 in multivariate analysis. The strongest evidence of modification was observed for rs1799931 (NAT2) on the relationship between pesticide poisoning and impaired vibration sense. CONCLUSIONS DNA variants of NAT2, PON1, and GSTM1 may modify OP neurotoxicity, and this requires further exploration.

No previous epidemiological study has investigated the combined association of long-term ambient nitrogen dioxide (NOThis study investigated the independent and co-pollutant association of long-term exposures to ambient air pollutants on asthma-associated outcomes in a cohort of schoolchildren in the Western Cape Province of South Africa.A total of 590 grade-4 schoolchildren residing in four informal settlements were studied. Spirometry and fractional exhaled nitric-oxide (FeNO) measurements were conducted, including a standardized questionnaire administered to caregivers at baseline and 12-months follow-up. Annual NOThe annual average concentration of PMThis study provided evidence that ambient NO

Background The individual effects of biological constituents of particulate matter (PM) such as fungal spores, on lung function in children are not well known. This study investigated the seasonal short-term effect of daily variation in Alternaria and Cladosporium fungal spores on lung function in schoolchildren. Methods This panel study evaluated 313 schoolchildren in informal settlements of the Western Cape of South Africa, exposed to spores of two commonly encountered fungi, Alternaria and Cladosporium species. The children provided forced-expiratory volume in 1-s (FEV1) and peak-expiratory flow (PEF) measurements thrice daily for two consecutive school-weeks in summer and winter. Daily PM10 levels, from a stationary ambient air quality monitor and fungal spore levels using spore traps were measured in each study area throughout the year. The effects of Alternaria and Cladosporium spores, on lung function were analysed for lag periods up to five-days, adjusting-for PM10, other pollen exposures, study area, and other host and meteorological factors. Same-day exposure-response curves were computed for both fungal species. Results There was more variability in Alternaria spores level with noticeable peaks in summer. There were consistent lag-effects for Alternaria on PEF compared to Cladosporium, with the largest PEF deficit observed in winter (mean deficit: 13.78 L/min, 95%CI: 24.34 to −3.23 L/min) per 10spores/m3 increase in Alternaria spores on lag day-2. Although there were no observable lag-effects for Alternaria and Cladosporium on FEV1, same-day effects of Cladosporium spores on FEV1 was present across both seasons. Threshold effects of Alternaria on both PEF and FEV1 deficits were apparent at levels of 100 spores/m3, but could not be explored for Cladosporium beyond the levels observed during the study. Conclusion The study provides evidence for the independent effects of daily exposure to ambient fungal spores of Alternaria and Cladosporium on lung function deficits, more especially in winter for PEF.

Shale gas exploration involving hydraulic fracturing (fracking) has been on South Africa's energy agenda since 2010 as a potential alternative to coal. Internationally, the desirability of fracking has been under debate, due to increasing evidence of associated environmental and health risks. There is limited research related to the public's knowledge and risk perceptions of fracking, and none whatsoever from South Africa. This cross-sectional study explored, through a household survey, knowledge of, health risk perceptions of, and information sources related to fracking of 102 Central Karoo residents. Our results indicated that 40% of the participants do not know what fracking is or the potential risks and benefits thereof. The media is participants' main information source (59.8%), and only half of the participants trust their information sources. Those with more trust in their information sources perceived fracking as posing a greater risk. Those believing fracking poses a low risk were more likely to ...

Background No previous epidemiological study has investigated the combined association of long-term ambient nitrogen dioxide (NO2) and particulate matter of diameter size-2.5 (PM2.5) exposure with asthma outcomes among schoolchildren in Africa. Objectives This study investigated the independent and co-pollutant association of long-term exposures to ambient air pollutants on asthma-associated outcomes in a cohort of schoolchildren in the Western Cape Province of South Africa. Methods A total of 590 grade-4 schoolchildren residing in four informal settlements were studied. Spirometry and fractional exhaled nitric-oxide (FeNO) measurements were conducted, including a standardized questionnaire administered to caregivers at baseline and 12-months follow-up. Annual NO2 and PM2.5 levels were estimated for each child's home using land-use regression modelling. Single- and two-pollutant models were constructed to assess the independent and co-pollutant association of both air pollutants (NO2 and PM2.5) on new cases of asthma-associated outcomes adjusting-for host characteristics, indoor exposures and study area. Results The annual average concentration of PM2.5 and NO2 were 10.01μg/m3 and 16.62μg/m3 respectively, across the four study areas, and were below the local Standards of 20μg/m3 and 40μg/m3, for both pollutants, respectively. In the two-pollutant-adjusted models, an interquartile range (IQR) increase of 14.2μg/m3 in NO2 was associated with an increased risk of new onset of ocular-nasal symptoms (adjusted odds ratio–aOR: 1.63, 95% CI: 1.01–2.60), wheezing (aOR: 3.57, 95% CI: 1.18–10.92), more than two or more asthma symptom score (aOR: 1.71, 95% CI: 1.02–2.86), and airway inflammation defined as FeNO > 35 ppb (aOR: 3.10, 95% CI: 1.10–8.71), independent of PM2.5 exposures. Conclusion This study provided evidence that ambient NO2 levels below local standards and international guidelines, independent of PM2.5 exposure, increases new cases of asthma-associated outcomes after 12-months.

Background Electronic media use is increasing in low- and middle-income countries, thus we aim to investigate the prevalence of different aspects of e-media use and its association to symptoms and neurocognitive outcomes in rural South Africa. Methods In the cohort study, “Child health Agricultural Pesticide study in South Africa (CapSA)”, of 1001 children and adolescents, aged 9–16 years, we enquired at baseline about the following aspects of e-media use: (1) call duration (2) total screen time (3) night-time awakenings from mobile phone use, and (4) Mobile Phone Problematic Use. Four health outcomes were included: sleep disturbance, health related quality of life (HRQoL), headaches and cognitive performance, assessed through six tests on domains of attention, memory and processing speed, using the iPad-based software, CAmbridge Neuropsychological Test Automated Battery (CANTAB). Linear regression analysis adjusted for relevant confounders was conducted with categorized exposure variables low, medium and high use. Results One third of the cohort (31.8%) are mobile phone users reporting average duration of calls per day up to 75 min (mean = 2.5 mins; SD = 8.9 mins). Amongst 46% of the cohort who report e-media device use, total screen time ranged from 1 min to 441 min (mean = 28.3; SD = 53.0). Findings Amongst those reporting regular night-time awakenings (≥1 times per week) from mobile phones, HRQol declined by 2.9 (95% CI: −6.1, 0.3), the sleep disturbance score increased by 2.0 (1.1, 2.9) units and headache impact score significantly increased by 5.4 (2.6; 8.2) units compared to non-exposed. Cognitive performance scores tended to be slightly improved mostly in moderate e-media users. The reaction response speed was consistently improved amongst all four exposure groups compared to non-users. Conclusion These results are among the first from Africa on benefits and risks associated with e-media use. Our findings imply that with regard to the education of adolescents, a vigilant balance is needed to profit from the beneficial effects of moderate e-media use on cognition, while preventing the negative side effects for HRQoL, sleep disturbance and headache severity.

BackgroundMany agricultural pesticides currently in use are hormonally active but few previous studies have investigated their effect on the reproductive and anthropometric development of pubertal ...

In developing countries, noise annoyance and noise sensitivity are not commonly investigated. The present study aimed to assess the annoyance and sensitivity to noise in 364 adults living in informal settings in the Western Cape Province, South Africa and to compare with a similar study conducted in Switzerland. Compared to Switzerland, higher percentages of highly noise sensitive individuals (women: 35.1% vs 26.9%; men: 25% vs 20.5%) and people highly annoyed to road traffic noise (women: 20.5% vs 12.4%; men: 17.9% vs 11.1%) were observed in South Africa. While in South Africa women were more annoyed to neighborhood noise than in Switzerland (21.1% vs 9.4%), this was not the case among men (7.1% vs 7.8%). Multivariable logistic regression models showed that in both countries men tended to be less sensitive and less annoyed by noise. Corresponding associations with age and education were somewhat different between the countries, which may be explained by socioeconomic and environmental differences. This study indicates that noise exposure considerably affects people living in informal settlements, and noise should be considered when improving the housing conditions.

In low- and middle-income countries, noise exposure and its negative health effects have been little explored. The present study aimed to assess the noise exposure situation in adults living in informal settings in the Western Cape Province, South Africa. We conducted continuous one-week outdoor noise measurements at 134 homes in four different areas. These data were used to develop a land use regression (LUR) model to predict A-weighted day-evening-night equivalent sound levels (Lden) from geographic information system (GIS) variables. Mean noise exposure during day (6:00-18:00) was 60.0 A-weighted decibels (dB(A)) (interquartile range 56.9-62.9 dB(A)), during night (22:00-6:00) 52.9 dB(A) (49.3-55.8 dB(A)) and average Lden was 63.0 dB(A) (60.1-66.5 dB(A)). Main predictors of the LUR model were related to road traffic and household density. Model performance was low (adjusted R2 = 0.130) suggesting that other influences than those represented in the geographic predictors are relevant for noise exposure. This is one of the few studies on the noise exposure situation in low- and middle-income countries. It demonstrates that noise exposure levels are high in these settings.

Background Modulation of organophosphate (OP) neurotoxicity by genetic polymorphisms of xenobiotic metabolising enzymes (XMEs) has not previously been investigated Objectives To investigate whether XMEs polymorphisms modify OP neurotoxicity among emerging farmers. Methods A cross-sectional study of 301 emerging farmers was conducted. Neurotoxicity testing included forward and backward recall digit span and vibration sensitivity testing. Questionnaire data included demography, potential confounders and work history of pesticide exposures. Genomic DNA was analysed from study participants for DNA variants of two glutathione S-transferases (GST), N-acetyltransferase 2 (NAT2) and Paraoxonase 1 (PON1). Results The median age of workers was 39 years (range: 30–48 years) of whom 54% were OP pesticide applicators. There was a low prevalence of the null genotype for GSTT1 (1%) and for GSTM1 (16%), while the genotypic frequency for the GA and AA grouping of rs1799931 (NAT2) was 10%. There was evidence of OP pesticide neurotoxicity modification by rs1799931 (NAT2), rs662 (PON1) and the null allele of GSTM1 in multivariate analysis. The strongest evidence of modification was observed for rs1799931 (NAT2) on the relationship between pesticide poisoning and impaired vibration sense. The increased prevalence of impaired vibration sense in OP poisoned compared to non-poisoned workers (Odds ratio=5.7, 95% confidence interval (CI): 1.4–22.7) was higher among those with the GG genotype than those with the GA and AA genotypes (Odds ratio=1.5, CI: 0.1–43.2). Conclusion DNA variants of NAT2, PON1 and GSTM1 may modify OP neurotoxicity and this requires further exploration

Background There is evidence from existing literature that ambient air pollutant exposure in early childhood likely plays an important role in asthma exacerbation and other respiratory symptoms, with greater effect among asthmatic children. However, there is inconclusive evidence on the role of ambient air pollutant exposures in relation to increasing asthma prevalence as well as asthma induction in children. At the population level, little is known about the potential synergistic effects between pollen allergens and air pollutants since this type of association poses challenges in uncontrolled real life settings. In particular, data from sub-Sahara Africa is scarce and virtually absent among populations residing in informal residential settlements. Methods/design A prospective cohort study of 600 school children residing in four informal settlement areas with varying potential ambient air pollutant exposure levels in the Western Cape in South Africa is carried-out. The study has two follow-up periods of at least six-months apart including an embedded panel study in summer and winter. The exposure assessment component models temporal and spatial variability of air quality in the four study areas over the study duration using land-use regression modelling (LUR). Additionally, daily pollen levels (mould spores, tree, grass and weed pollen) in the study areas are recorded. In the panel study asthma symptoms and serial peak flow measurements is recorded three times daily to determine short-term serial airway changes in relation to varying ambient air quality and pollen over 10-days during winter and summer. The health outcome component of the cohort study include; the presence of asthma using a standardised ISAAC questionnaire, spirometry, fractional exhaled nitric-oxide (FeNO) and the presence of atopy (Phadiatop). Discussion This research applies state of the art exposure assessment approaches to characterize the effects of ambient air pollutants on childhood respiratory health, with a specific focus on asthma and markers of airway inflammation (FeNO) in South African informal settlement areas by considering also pollen counts and meteorological factors. The study will generate crucial data on air pollution and asthma in low income settings in sub-Sahara Africa that is lacking in the international literature.