Contamination of rural surface and ground water by endosulfan in farming areas of the Western Cape, South Africa

Association between Fish Consumption during Pregnancy and Maternal and Neonatal Outcomes: A Statistical Study in Southern Italy

Background: This research aimed to evaluate the association between the monthly consumption of fish (differentiated by type) and both gestational and neonatal outcomes. Methods: Women who were admitted for delivery in the last 6 months of 2023 were prospectively included and divided according to type of fish consumed (based on DHA and mercury content) and frequency of consumption. Neonatal outcomes included weight, length, head circumference, and 1st and 5th minute Apgar scores. Maternal outcomes were threats of abortion, preterm birth, gestational diabetes and hypertension, cesarean section, and differential body mass index (BMI). Results: Small-size oily fish with high DHA and low mercury content (type B fish) consumption was positively associated with neonatal weight and head circumference, and less weight gain in pregnancy. It was also significantly associated with lower incidences of gestational diabetes and hypertension, and cesarean section. Correlation between differential BMI and monthly consumption of fish resulted in statistical significance, especially in type B fish consumers. Conclusions: The consumption of type B fish was significantly associated with increased neonatal weight and head circumference and better maternal outcomes.

Efficacy of treating bacterial bioaerosols with weakly acidic hypochlorous water: A simulation chamber study

The COVID-19 pandemic highlighted the dangers of airborne transmission and the risks of pathogen-containing small airborne droplet inhalation as an infection route. As a pathogen control, Weakly Acidic Hypochlorous Water (WAHW) is used for surface disinfection. However, there are limited assessments of air disinfection by WAHW against airborne pathogens like bioaerosols. This was an empirical study evaluating the disinfection efficacy of WAHW in an atmospheric simulation chamber system against four selected model bacteria. The strains tested included Staphylococcus aureus (SA), Escherichia coli (EC), Pseudomonas aeruginosa (PA), and Pseudomonas aeruginosa (PAO1). Each bacterial solution was nebulized into the chamber system as the initial step, and bioaerosol was collected into the liquid medium by a bio-sampler for colony forming units (CFU) determination. Secondly, the nebulized bacterial bioaerosol was exposed to nebulized double distilled water (DDW) as the control and nebulized 150 ppm of WAHW as the experimental groups. After the 3 and 30-min reaction periods, the aerosol mixture inside the chamber was sampled in liquid media and then cultured on agar plates with different dilution factors to determine the CFU. Survival rates were calculated by a pre-exposed CFU value as a reference point. The use of WAHW decreased bacterial survival rates to 1.65-30.15% compared to the DDW control. PAO1 showed the highest survival rates and stability at 3 min was higher than 30 min in all experiments. Statistical analysis indicated that bacteria survival rates were significantly reduced compared to the controls. This work verifies the bactericidal effects against Gram-positive/negative bioaerosols of WAHW treatment. As WAHW contains chlorine in the acid solution, residual chlorine air concentration is a concern and the disinfection effect at different concentrations also requires investigation. Future studies should identify optimal times to minimize the treated time range and require measurements in a real environment.

Two-dimensional layered MoSe2/graphene oxide (GO) nanohybrid coupled with the specific immune-recognition element for rapid detection of endosulfan

Endosulfan (En) is an organochlorine biocide (OCB), that ends up in the environment due to the enzymatic and microsomal activity even though it is not accumulated in living tissue. Endosulfan acts as an organic micro-pollutant which disrupts land as well as aquatic ecosystem. In the present study, we chemically modified endosulfan and conjugated it with a carrier protein to produce an immune response. The generated antibodies were tested for specificity against En, and characterized before further use. Transition Metal Chalcogenides (TMC) showed excellent optoelectrical potential due to its direct bandgap and distinct physical as well as chemical characteristics. Herein, we synthesized a novel nanohybrid using MoSe2 in combination with graphene oxide (GO) and characterized thoroughly. This was similar to graphene-based metal chalcogenides which were further used in this study to fabricate biosensor for the sensitive detection of En. The in-house developed antibodies (En-Ab) were coupled with the nanohybrid to make MoSe2/GO/En-Ab electrode. Fabricated electrode was tested for electrochemical parameters using differential pulse voltammetry (DPV). Working efficiency of the fabricated electrode i.e., limit of detection (LOD), was found to be 7.45 ppt. In conclusion, we hypothesized that the synthesized TMC nanohybrids could be employed for biosensing of endosulfan, and can likely be developed to test field samples.

The benefit of using in vitro bioassays to screen agricultural samples for oxidative stress: South Africa's case

Applied pesticides end up in non-target environments as complex mixtures. When bioavailable, these chemicals pose a threat to living organisms and can induce oxidative stress (OS). In this article, attention is paid to OS and the physiological role of the antioxidant defense system. South African and international literature was reviewed to provide extensive evidence of pesticide-induced OS in non-target organisms, in vivo and in vitro. Although in vitro approaches are used internationally, South African studies have only used in vivo methods. Considering ethical implications, the authors support the use of in vitro bioassays to screen environmental matrices for their OS potential. Since OS responses are initiated and measurable at lower cellular concentrations compared to other toxicity endpoints, in vitro OS bioassays could be used as an early warning sign for the presence of chemical mixtures in non-target environments. Areas of concern in the country could be identified and prioritized without using animal models. The authors conclude that it will be worthwhile for South Africa to include in vitro OS bioassays as part of a battery of tests to screen environmental matrices for biological effects. This will facilitate the development and implementation of biomonitoring programs to safeguard the South African environment.

Toxicological Effects of Fine Particulate Matter (PM2.5): Health Risks and Associated Systemic Injuries-Systematic Review

Previous studies focused on investigating particulate matter with aerodynamic diameter ≤ 2.5 µm (PM2.5) have shown the risk of disease development, and association with increased morbidity and mortality rates. The current review investigate epidemiological and experimental findings from 2016 to 2021, which enabled the systemic overview of PM2.5's toxic impacts on human health. The Web of Science database search used descriptive terms to investigate the interaction among PM2.5 exposure, systemic effects, and COVID-19 disease. Analyzed studies have indicated that cardiovascular and respiratory systems have been extensively investigated and indicated as the main air pollution targets. Nevertheless, PM2.5 reaches other organic systems and harms the renal, neurological, gastrointestinal, and reproductive systems. Pathologies onset and/or get worse due to toxicological effects associated with the exposure to this particle type, since it can trigger several reactions, such as inflammatory responses, oxidative stress generation and genotoxicity. These cellular dysfunctions lead to organ malfunctions, as shown in the current review. In addition, the correlation between COVID-19/Sars-CoV-2 and PM2.5 exposure was also assessed to help better understand the role of atmospheric pollution in the pathophysiology of this disease. Despite the significant number of studies about PM2.5's effects on organic functions, available in the literature, there are still gaps in knowledge about how this particulate matter can hinder human health. The current review aimed to approach the main findings about the effect of PM2.5 exposure on different systems, and demonstrate the likely interaction of COVID-19/Sars-CoV-2 and PM2.5.

Exposure to endosulfan can cause long term effects on general biology, including the reproductive system of mice

Increased infertility in humans is attributed to the increased use of environmental chemicals in the last several decades. Various studies have identified pesticides as one of the causes of reproductive toxicity. In a previous study, infertility was observed in male mice due to testicular atrophy and decreased sperm count when a sublethal dose of endosulfan (3 mg/kg) with a serum concentration of 23 μg/L was used. However, the serum concentration of endosulfan was much higher (up to 500 μg/L) in people living in endosulfan-exposed areas compared to the one used in the investigation. To mimic the situation in an experimental setup, mice were exposed to 5 mg/kg body weight of endosulfan, and reproductive toxicity and long-term impact on the general biology of animals were examined. HPLC analysis revealed a serum concentration of ∼50 μg/L of endosulfan after 24 h endosulfan exposure affected the normal physiology of mice. Histopathological studies suggest a persistent, severe effect on reproductive organs where vacuole degeneration of basal germinal epithelial cells and degradation of the interstitial matrix were observed in testes. Ovaries showed a reduction in the number of mature Graafian follicles. At the same time, mild vacuolation in liver hepatocytes and changes in the architecture of the lungs were observed. Endosulfan exposure induced DNA damage and mutations in germ cells at the molecular level. Interestingly, even after 8 months of endosulfan exposure, we observed increased DNA breaks in reproductive tissues. An increased DNA Ligase III expression was also observed, consistent with reported elevated levels of MMEJ-mediated repair. Further, we observed the generation of tumors in a few of the treated mice with time. Thus, the study not only explores the changes in the general biology of the mice upon exposure to endosulfan but also describes the molecular mechanism of its long-term effects.

A survey on the correlation between PM2.5 concentration and the incidence of suspected and positive cases of COVID-19 referred to medical centers: A case study of Tehran

COVID-19, one of the greatest health challenges of the present century, has infected millions of people and caused more than 6 million deaths worldwide. The causative agent of this disease is the new virus SARS-CoV-2; which continues to spread globally and sometimes with new and more complex aspects than before. The present study is an observational study aimed to investigate the role of AQI; PM_2.5 and its relationship with the incidence of suspected cases (SC) and positive cases (PC) of COVID-19 at different levels of the air quality index (AQI) in Tehran, the capital of Iran in the period from Feb 20th, 2020 to Feb 22nd, 2021. Data on AQI were collected online from the air monitoring website of Air Quality Control Company under the supervision of Tehran Municipality. The data on suspected and positive cases were obtained from the Iranian Ministry of Health. The results and statistical analysis (Pearson correlation test) showed that with the increase of AQI level, the number of suspected cases (SC) and positive cases (PC), also increased (P-value<0.01). The average daily number of suspected and positive COVID-19 cases referred to medical centers, at different levels of the AQI was as follows: level II: yellow, moderate (SC: N_ave = 466; PC: N_ave = 223), level III: orange, unhealthy for sensitive groups (SC: N_ave = 564; PC: N_ave = 275), and Level IV: red, unhealthy (SC: N_ave = 558; PC: N_ave = 294). The results of the GEE for seasonal comparison (winter as reference season), showed that there is an epidemiological pattern in autumn with colder weather compared to other seasons in both suspected (Cl: %95, B = 408.94) and positive (Cl: %95, B = 83.42) cases of COVID-19. The results of this study will serve policymakers as an informative tool for guidance on the importance of the role of air pollution in viral epidemics.

Air pollution and meteorological variables' effects on COVID-19 first and second waves in Spain

The aim of this research is to study the influence of atmospheric pollutants and meteorological variables on the incidence rate of COVID-19 and the rate of hospital admissions due to COVID-19 during the first and second waves in nine Spanish provinces. Numerous studies analyze the effect of environmental and pollution variables separately, but few that include them in the same analysis together, and even fewer that compare their effects between the first and second waves of the virus. This study was conducted in nine of 52 Spanish provinces, using generalized linear models with Poisson link between levels of PM₁₀, NO₂ and O₃ (independent variables) and maximum temperature and absolute humidity and the rates of incidence and hospital admissions of COVID-19 (dependent variables), establishing a series of significant lags. Using the estimators obtained from the significant multivariate models, the relative risks associated with these variables were calculated for increases of 10 µg/m³ for pollutants, 1 °C for temperature and 1 g/m³ for humidity. The results suggest that NO₂ has a greater association than the other air pollution variables and the meteorological variables. There was a greater association with O₃ in the first wave and with NO₂ in the second. Pollutants showed a homogeneous distribution across the country. We conclude that, compared to other air pollutants and meteorological variables, NO₂ is a protagonist that may modulate the incidence and severity of COVID-19, though preventive public health measures such as masking and hand washing are still very important.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13762-022-04190-z.

Quantitative assessment of multiple pesticides in silicone wristbands of children/guardian pairs living in agricultural areas in South Africa

Little is known about personal and time-integrated exposure to past and current used pesticides in agricultural areas and within-family exposure similarities. We aimed to assess exposure to pesticides using silicone wristbands in child/guardian pairs living on farms and in villages within two agricultural areas in South Africa. Using silicone wristbands, we quantified 21 pesticides in child/guardian pairs in 38 households over six days in 2018. Levels (in ng/g wristband) of pesticides and their transformation products (12 current-use pesticides and nine organochlorine pesticides) were measured using GC-MS/MS. We assessed the correlation between pesticide levels and between household members using Spearman correlation coefficients (r_s). Multivariable generalized least squares (GLS) models, using household id as intercept, were used to determine level of agreement between household members, exposure differences between children and guardians and exposure predictors (study area, household location [farm vs. village] and household pesticide use). We detected 16 pesticides with highest detection frequencies for deltamethrin (89%), chlorpyrifos (78%), boscalid (56%), cypermethrin (55%), and p,p'-DDT (48%). Most wristbands (92%) contained two or more pesticides (median seven (range one to 12)). Children had higher concentrations than guardians for four pesticides. Correlation between the pesticide levels were in most cases moderate (rs 0.30-0.68) and stronger in children than in guardians. Five pesticides showed moderate to strong correlation between household members, with the strongest correlation for boscalid (r_s 0.84). Exposure differences between the two agricultural areas were observed for chlorpyrifos, diazinon, prothiofos, cypermethrin, boscalid, p,p'-DDT and p,p'-DDE and within areas for cypermethrin. We showed that for several pesticides children had higher exposure levels than guardians. The positive correlations observed for child/guardian pairs living in the same household suggest non-occupational shared exposure pathways in these communities.

Does air pollution explain COVID-19 fatality and mortality rates? A multi-city study in São Paulo state, Brazil

Since air pollution compromise the respiratory system and COVID-19 disease is caused by a respiratory virus, it is expected that air pollution plays an important role in the current COVID-19 pandemic. Exploratory studies have observed positive associations between air pollution and COVID-19 cases, deaths, fatality, and mortality rate. However, no study focused on Brazil, one of the most affected countries by the pandemic. Thus, this study aimed to understand how long-term exposure to PM₁₀, PM_2.5, and NO₂ contributed to COVID-19 fatality and mortality rates in São Paulo state in 2020. Air quality data between 2015 and 2019 in 64 monitoring stations within 36 municipalities were considered. The COVID-19 fatality was calculated considering cases and deaths from the government's official data and the mortality rate was calculated considering the 2020 population. Linear regression models were well-fitted for PM_2.5 concentration and fatality (R² = 0.416; p = 0.003), NO₂ concentration and fatality (R² = 0.232; p = 0.005), and NO₂ concentration and mortality (R² = 0.273; p = 0.002). This study corroborates other authors' findings and enriches the discussion for having considered a longer time series to represent long-term exposure to the pollutants and for having considered one of the regions with the highest incidence of COVID-19 in the world. Thus, it reinforces measures to reduce the concentration of air pollutants which are essential for public health and will increase the chance to survive in future respiratory disease epidemics.

Air quality changes in cities during the COVID-19 lockdown: A critical review

In response to the rapid spread of coronavirus disease-2019 (COVID-19) within and across countries and the need to protect public health, governments worldwide introduced unprecedented measures such as restricted road and air travel and reduced human mobility in 2020. The curtailment of personal travel and economic activity provided a unique opportunity for researchers to assess the interplay between anthropogenic emissions of primary air pollutants, their physical transport, chemical transformation, ultimate fate and potential health impacts. In general, reductions in the atmospheric levels of outdoor air pollutants such as particulate matter (PM), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and volatile organic compounds (VOCs) were observed in many countries during the lockdowns. However, the levels of ozone (O3), a secondary air pollutant linked to asthma and respiratory ailments, and secondary PM were frequently reported to remain unchanged or even increase. An increase in O3 can enhance the formation of secondary PM2.5, especially secondary organic aerosols, through the atmospheric oxidation of VOCs. Given that the gaseous precursors of O3 (VOCs and NOx) are also involved in the formation of secondary PM2.5, an integrated control strategy should focus on reducing the emission of the common precursors for the co-mitigation of PM2.5 and O3 with an emphasis on their complex photochemical interactions. Compared to outdoor air quality, comprehensive investigations of indoor air quality (IAQ) are relatively sparse. People spend more than 80% of their time indoors with exposure to air pollutants of both outdoor and indoor origins. Consequently, an integrated assessment of exposure to air pollutants in both outdoor and indoor microenvironments is needed for effective urban air quality management and for mitigation of health risk. To provide further insights into air quality, we do a critical review of scientific articles, published from January 2020 to December 2020 across the globe. Finally, we discuss policy implications of our review in the context of global air quality improvement.

Global effect of city-to-city air pollution, health conditions, climatic & socio-economic factors on COVID-19 pandemic

The rate of spread of the global pandemic calls for much attention from the empirical literature. The limitation of extant literature in assessing a comprehensive COVID-19 portfolio that accounts for complexities in the spread and containment of the virus underscores this study. We investigate the effect of city-to-city air pollutant species, meteorological conditions, underlying health conditions, socio-economic and demographic factors on COVID-19 health outcomes. We utilize a panel estimation of 615 cities in 6 continents from January 1 to June 11, 2020. While social distancing measures, movement restrictions and lockdown are reported to have improved environmental quality, we show that ambient PM_2.5 remains unhealthy and above the acceptable threshold in several countries. Our empirical assessment shows that while ambient PM_2.5, nitrogen dioxide, ozone, pressure, dew, Windgust, and windspeed increase the spread of COVID-19, high relative humidity and ambient temperature have mitigation effect on COVID-19, hence, decreases the number of confirmed cases. We report 66.3% of countries projected to experience a second wave of COVID-19 if government stringency and safety protocols are not enhanced. By extension, our assessments demonstrate that several factors namely underlying health conditions, meteorological, air pollution, health system quality, socio-economic and demographics spur the reproduction effect of COVID-19 across countries. Our study highlights the importance of government stringency in containing the spread of COVID-19 and its impacts.

Environmental impact of COVID-19 led lockdown: A satellite data-based assessment of air quality in Indian megacities

The strategies to contain the spread of COVID-19 pandemic, including restricted human movement and economic activities, have shown positive impacts on the environment. Present research analysed the effects of COVID-19 led lockdown on air quality with special reference to major pollutants, namely nitrogen dioxide (NO₂), carbon monoxide (CO), sulphur dioxide (SO₂) and aerosol optical depth (AOD). The assessment has been conducted for megacities of India (Delhi, Mumbai, Bengaluru, Chennai and Kolkata) for four months, that is, March and April in 2019 and 2020 using Sentinel 5P and MCD19A2 data. A decrease in concentrations of air pollutants, specifically NO₂ and SO_2, has been observed during the lockdown period in all the cities; whereas CO and AOD have exhibited discrete pattern of spatio-temporal variation. Four megacities except Kolkata have revealed a positive correlation between NO₂ concentration and population density. The results conclude overall improvement in air quality during COVID-19 led lockdown. The current situation provides a unique opportunity to implement a structural economic change that could help us move towards a city with low emission economy. Realizing the achievable improvement of air quality, the study suggests further in-depth research on source attribution of individual pollutants to assess the prospect of emission reduction actions.

The novel SARS-CoV-2 pandemic: Possible environmental transmission, detection, persistence and fate during wastewater and water treatment

The contagious SARS-CoV-2 virus, responsible for COVID-19 disease, has infected over 27 million people across the globe within a few months. While literature on SARS-CoV-2 indicates that its transmission may occur predominantly via aerosolization of virus-laden droplets, the possibility of alternate routes of transmission and/or reinfection via the environment requires considerable scientific attention. This review aims to collate information on possible transmission routes of this virus, to ascertain its fate in the environment. Concomitant with the presence of SARS-CoV-2 viral RNA in faeces and saliva of infected patients, studies also indicated its occurrence in raw wastewater, primary sludge and river water. Therefore sewerage system could be a possible route of virus outbreak, a possible tool to assess viral community spread and future surveillance technique. Hence, this review looked into detection, occurrence and fate of SARS-CoV-2 during primary, secondary, and tertiary wastewater and water treatment processes based on published literature on SARS-CoV and other enveloped viruses. The review also highlights the need for focused research on occurrence and fate of SARS-CoV-2 in various environmental matrices. Utilization of this information in environmental transmission models developed for other enveloped and enteric viruses can facilitate risk assessment studies. Preliminary research efforts with SARS-CoV-2 and established scientific reports on other coronaviruses indicate that the threat of virus transmission from the aquatic environment may be currently non-existent. However, the presence of viral RNA in wastewater provides an early warning that highlights the need for effective sewage treatment to prevent a future outbreak of SARS-CoV-2.

Emerging organic contaminants in shallow groundwater underlying two contrasting peri-urban areas in Uganda

This study investigated the occurrence and seasonal variation in concentrations of emerging organic contaminants (EOCs) in shallow groundwater underlying two peri-urban areas of Bwaise (highly urbanised) and Wobulenzi (moderately urbanised) in Uganda. Twenty-six antibiotics, 20 hydrocarbons, including 16 polycyclic aromatic hydrocarbons (PAHs), and 59 pesticides were investigated. Ampicillin and benzylpenicillin were the most frequently detected antibiotics in both areas, although at low concentrations to cause direct harm to human health, but could lead to a proliferation of antibiotic resistance genes. The most frequently detected hydrocarbons in Bwaise were naphthalene and xylene while anthracene and fluoranthene were the most frequent in Wobulenzi, also at low concentrations for ecological impact at long-term exposure. Molecular diagnostic ratios indicated pyrogenic and pyrolytic sources of PAHs in both areas. Cypermethrin (for vermin control) was the most frequent pesticide in Bwaise while metalaxyl (attributed to agriculture) was the most frequent in Wobulenzi. Banned organochlorines (8) were also detected in both areas in low concentrations. The pesticide concentrations between the two areas significantly differed (Z = - 3.558; p < 0.01), attributed to contrasting land-use characteristics. In Wobulenzi (wet season), the total pesticide concentrations at all the locations exceeded the European Community parametric guideline value while 75% of the detected compounds exceeded the individual pesticide guideline value. Thus, the antibiotic and pesticide residues in shallow groundwater underlying both Bwaise and Wobulenzi pose potential adverse ecological effects at long-term exposure. Monitoring of EOCs in both highly and moderately urbanised catchments should be strengthened towards mitigating associated risks.

Air pollution exposure and COVID-19: A look at mortality in Mexico City using individual-level data

We use individual-level data to estimate the effects of long- and short-term exposure to air pollution (PM2.5) on the probability of dying from COVID-19. To the best of our knowledge, our study is the first to look at this relationship using individual-level data. We find that for Mexico City there is evidence of a positive relationship between pollution and mortality that significantly grows with age and that appears to be mostly driven by long- rather than short-term exposure. By using a rich set of individual- and municipal-level covariates we are able to isolate the effect of exposure to pollution from other crucial factors, thus alleviating endogeneity concerns related to selection. Our results provide yet another reason for the need to implement environmental strategies that will reduce the exposure to air pollution: it is a key element to improve the general population's health. In addition, and considering that at this moment we do not know when the pandemic will stop or if SARS-CoV-2 will become a recurrent threat, the relationship that we uncovered suggests that financial resources should be allocated to improve medical services in those areas where PM2.5 concentrations tend to be high.

Rapid and Sensitive Quantification of the Pesticide Lindane by Polymer Modified Electrochemical Sensor

Lindane is documented by the Environmental Protection Agency (EPA) as one of the most toxic registered pesticides. Conventional detection of lindane in the environment requires manual field sampling and complex, time-consuming analytical sample handling relying on skilled labor. In this study, an electrochemical sensing system based on a modified electrode is reported. The system is capable of detecting lindane in aqueous medium in only 20 s. The surface of a conventional carbon electrode is modified with a film of conductive polymer that enables detection of lindane down to 30 nanomolar. The electrode modification procedure is simple and results in a robust sensor that can withstand intensive use. The sensitivity of the sensor is 7.18 µA/µM and the performance was demonstrated in the determination of lindane in spiked ground water. This suggests that the sensor is potentially capable of providing useful readings for decision makers. The rapid and sensitive quantification of lindane in aqueous medium is one step forward to new opportunities for direct, autonomous control of the pesticide level in the environment.

Association of activities related to pesticide exposure on headache severity and neurodevelopment of school-children in the rural agricultural farmlands of the Western Cape of South Africa

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.

Agrochemicals in freshwater systems and their potential as endocrine disrupting chemicals: A South African context

South Africa is the largest agrochemical user in sub-Saharan Africa, with over 3000 registered pesticide products. Although they reduce crop losses, these chemicals reach non-target aquatic environments via leaching, spray drift or run-off. In this review, attention is paid to legacy and current-use pesticides reported in literature for the freshwater environment of South Africa and to the extent these are linked to endocrine disruption. Although banned, residues of many legacy organochlorine pesticides (endosulfan and dichlorodiphenyltrichloroethane (DDT)) are still detected in South African watercourses and wildlife. Several current-use pesticides (triazine herbicides, glyphosate-based herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D) and chlorpyrifos) have also been reported. Agrochemicals can interfere with normal hormone function of non-target organism leading to various endocrine disrupting (ED) effects: intersex, reduced spermatogenesis, asymmetric urogenital papillae, testicular lesions and infertile eggs. Although studies investigating the occurrence of agrochemicals and/or ED effects in freshwater aquatic environments in South Africa have increased, few studies determined both the levels of agricultural pesticides present and associated ED effects. The majority of studies conducted are either laboratory-based employing in vitro or in vivo bioassays to determine ED effects of agrochemicals or studies that investigate environmental concentrations of pesticides. However, a combined approach of bioassays and chemical screening will provide a more comprehensive overview of agrochemical pollution of water systems in South Africa and the risks associated with long-term chronic exposure.

Global scale distribution, seasonal changes and long-range transport potentiality of endosulfan in the surface seawater and air

Endosulfan I, II, and sulfate were detected in the atmosphere and surface seawater on a global scale during three Chinese National Arctic-Antarctic Research Expeditions in 2016 and 2017. Concentrations of the three species displayed seasonal variations in seawater in the Northern Hemisphere but remained steadily low on Antarctic coasts. Endosulfan sulfate was predominant in the Northern Hemisphere, whereas isomer I was more abundant in the Southern Hemisphere. Endosulfan was detected in the atmosphere over the western Pacific Ocean but rarely in the central Arctic and North Atlantic oceans. Its concentration in seawater increased with increasing latitude in the Southern Ocean. Although fugacity ratios indicate a strong potential for deposition of endosulfan, air-seawater exchange may be slow, as suggested by the large differences between atmospheric and seawater concentrations. Ocean current endosulfan loads varied markedly between seasons. Three-day backward trajectories indicate that Northeast Asia is the major source of atmospheric endosulfan in the western Pacific Ocean, whereas the central Arctic and North Atlantic oceans are affected more by local air masses.

Determination and ecological risk assessment of two endocrine disruptors from River Buffalo, South Africa

4-tert-Octylphenol (4-tOP) and triclosan (TCS) are endocrine disruptors which have been detected in environmental matrices such as air, soil and water at ultra-low levels. Exposure to endocrine disruptors may account at least in part, for the global increase in the incidence of non-communicable diseases like cancers and diabetes and may also lead to an imbalance in the aquatic ecosystem. River Buffalo is an important natural resource in the Eastern Cape of South Africa serving more than half a million people. The presence of the two compounds in the river water hitherto unknown was investigated during winter seasons using solid-phase extraction and gas chromatography-mass spectrometric techniques. The sampling points differed by some physicochemical parameters. The concentration of 4-tOP ranged 0-755 ng/L, median value 88.1 ng/L while that of TCS ranged 0-1264.2 ng/L and the median value was 82.1 ng/L. Hazard quotient as an index of exposure risk varied according to daphnids ˃ fish ˃ algae for 4-tOP exposure while HQ for TCS exposure was algae > daphnids = fish showing that both compounds were capable of causing imbalance in the aquatic ecosystem. Graphical abstract.

Qualitative assessment of 27 current-use pesticides in air at 20 sampling sites across Africa

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.

A vulnerability-based approach to human-mobility reduction for countering COVID-19 transmission in London while considering local air quality

An ecologic analysis was conducted to explore the correlation between air pollution, and COVID-19 cases and fatality rates in London. The analysis demonstrated a strong correlation (R2 > 0.7) between increment in air pollution and an increase in the risk of COVID-19 transmission within London boroughs. Particularly, strong correlations (R2 > 0.72) between the risk of COVID-19 fatality and nitrogen dioxide and particulate matter pollution concentrations were found. Although this study assumed the same level of air pollution across a particular London borough, it demonstrates the possibility to employ air pollution as an indicator to rapidly identify the city's vulnerable regions. Such an approach can inform the decisions to suspend or reduce the operation of different public transport modes within a city. The methodology and learnings from the study can thus aid in public transport's response to COVID-19 outbreak by adopting different levels of human-mobility reduction strategies based on the vulnerability of a given region.

Selected Insect Pests of Economic Importance to Brassica oleracea, Their Control Strategies and the Potential Threat to Environmental Pollution in Africa

The most common destructive insect pests affecting cabbages in African smallholder farmers include Plutella xylostella, Helula undalis, Pieris brassicae, Brevycoryne brassicae, Trichoplusia ni and Myzus persicae. Those insect pests infest cabbages at different stages of growth, causing huge damage and resulting into huge yield losses. The African smallholder farmers use cultural and synthetic pesticides to control insect pests and minimize infestations. The cultural practices like crop rotation, weeding and handpicking are used to minimize the invasion of cabbage pests. However, those practices are not sufficiently enough to control cabbage insect pests although they are cheap and safe to the environment. Also, the African smallholder famers rely intensively on the application of broad-spectrum of synthetic pesticides to effectively control the cabbage pests in the field. Due to severe infestation of cabbages caused by those insects, most of African smallholder farmers decide to; first, increase the concentrations of synthetic pesticides beyond the recommended amount by manufacturers. Secondly, increase the rate of application of the synthetic pesticides throughout the growing season to effectively kill the most stubborn insect pests infesting cabbages (Brassica oleracea var. capitata). Thirdly, they mix more than two synthetic pesticides for the purpose of increasing the spectrum of killing the most stubborn insect pests in the field. All those scenarios intensify the environmental pollution especially soil and water pollution. Moreover, most of insecticides sprayed are made with broad-spectrum and are hazardous chemicals posing environmental pollution and threats to natural enemies’ ecosystems. Therefore, this paper reviews Brassica oleracea var. capitata insect pests and control measures as a potential environmental pollution threat in African smallholder farmers.

Bioaccumulation and Distribution Behavior of Endosulfan on a Cichlid Fish: Differences Between Exposure to the Active Ingredient and a Commercial Formulation

Persistent organic pollutants reach aquatic ecosystems during application and can bioconcentrate/biomagnify because of their lipophilic nature. Toxicological studies focus almost exclusively on the active ingredients of pesticides, instead of commercial formulations, whose toxicity can differ as a result of nonspecified ingredients. The intensive use of endosulfan as a wide-ranging insecticide over the last few decades makes it one of the most frequently detected contaminants in the aquatic environment, even after it has been restricted worldwide. The aim of the present study was to evaluate the bioaccumulation and organ distribution of waterborne endosulfan in the freshwater fish Cichlasoma dimerus, comparing the active ingredient and a commercial formulation. Males were exposed to 0.7 μg/L endosulfan for 2 wk, which was quantified (gas chromatography with an electron capture detector) in the liver, testes, gills, brain, and muscle. The results suggest rapid metabolism of α-endosulfan and β-endosulfan isomers to endosulfan sulfate (endosulfan-S) in tissues. Isomer levels were highest in gills, indicative of recent uptake. Levels of endosulfan-S were highest in liver and testes for the active ingredient and testes and brain for the commercial formulation. For the active ingredient, endosulfan-S levels showed a positive correlation with organ-lipid percentage. No correlation was evident for the commercial formulation, indicating that the presence of adjuvants alters endosulfan distribution because gills and liver showed a higher uptake and mobilization of β-endosulfan. These differences in organ distribution may alter tissue-specific toxicity; therefore, additives cannot be considered inactive even if nontoxic. Environ Toxicol Chem 2020;39:604-611. © 2019 SETAC.

Occurrence of organochlorine pesticide residues in biological and environmental matrices in Africa: A two-decade review

The widespread use of organochlorine pesticides (OCPs), essentially for the control of insects and the cultivation of food crops, has led to the pollution of ecosystems. Despite being banned several years ago in the developed world, extensive use remains ongoing on the African continent. This review summarizes the occurrence, distributions, sources, and trends of OCPs in seven environmental matrices (atmosphere, water, sediments, soils, biota, human fluids and food products) in Africa. Findings in this review revealed that α-HCH, β-HCH dichlorodiphenyltrichloroethane (DDTs), and endosulfans were the most persistent OCP residues in the African environment, particularly DDTs in breast milk samples occurring in levels above the WHO stipulated limits, thus indicating a call for concern. Also, there was paucity of data available on OCP concentrations in ambient air. Future research efforts should prioritize testing these pollutants in the atmosphere, especially in countries where they are used more frequently. While most POP analysis studies used gas chromatography coupled to electron capture detector or mass spectrometer, it is recommended that further studies should use more sensitive analytical techniques such as gas chromatography with tandem mass spectrometry (GC-MS/MS), or gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS). These instruments allow for the detection of secondary and tertiary metabolites, especially those found in water, biota and food products, which are critical vectors of OCPs to human and animal bodies. Training of farmers and other domestic users on the handling of pesticides is proposed.

Occurrence and treatment of contaminants of emerging concern in the African aquatic environment: Literature review and a look ahead

Awareness about the rising detection and reported (eco)toxicological effects of contaminants of emerging concern (CECs, e.g. pharmaceuticals and personal care products - PPCPs - and modern pesticides) in the aquatic environment is growing. CECs are increasingly reported in the African aquatic environment, although the amount of data available is still limited. In this work, a comprehensive review is presented on the occurrence of CECs in wastewater, sludge, surface water, sediment, groundwater and drinking water of Africa. Further attention is given to the performance of wastewater stabilization ponds (WSPs) and trickling filters (TF) with respect to CECs removal. For the first time, we also look at the state of knowledge on the performance of point-of-use technologies (POUs) regarding the removal of CECs in drinking water. Generally, CECs in Africa occur at the same order of magnitude as in the Western world. However, for particular groups of compounds and at specific locations such as informal settlements, clearly higher concentrations are reported in Africa. Whereas antiretroviral and antimalarial drugs are rarely detected in the Western world, occurrence patterns in Africa reveal concentrations up to >100 μg L^-1. Removal efficiencies of WSPs and TFs focus mainly on PPCPs and vary significantly, ranging from no removal (e.g. carbamazepine) to better than 99.9% (e.g. paracetamol). Despite the rising adoption of POUs, limited but promising information is available on their performance regarding CECs treatment in drinking water, particularly for the low-cost devices (e.g. ceramic filters and solar disinfection - SODIS) being adopted in Africa and other developing countries.

Temporal variation of pesticide mixtures in rivers of three agricultural watersheds during a major drought in the Western Cape, South Africa

South Africa is the leading pesticide user in Sub-Saharan Africa. However, little is known about the occurrence of pesticide mixtures in surface water and potential environmental risks in Africa. This study investigated the occurrence of pesticides mixtures in three watersheds during a drought year in South Africa. The study was conducted in the Krom River, Berg River and Hex River watersheds within larger agriculture systems in the Western Cape. Pesticide spray records were collected from 38 farms. A total of 21 passive water samplers (styrenedivinylbenzene disks (SDB)) were deployed, each for two weeks per month, over seven sampling rounds during the main pesticide application period between July 2017 and January 2018. Samples were analyzed for 248 pesticide compounds using LC-HR-MS/MS. Pesticide occurrence was analyzed for temporal agreement with pesticide spraying events (Cohen's κ) and correlation with rainfall patterns and river discharge (Pearson correlation (r _p )). Pesticide time-weighted average concentrations were estimated and compared to environmental quality standards (EQS). According to the farm spray records, 96 different pesticides were sprayed during the sampling period and differed considerably between the three study areas, seasons and crops grown. In total, 53 compounds were detected in river water. We detected 39% of compounds from the spraying records and demonstrated close temporal correlations of seasonal patterns for 11 pesticide compounds between reported on spraying records and observations in the streams (κ = 0.90). However, 23 detected pesticides were not found on spray records, many of them being herbicides. Most of the estimated two-week average pesticide concentrations were below 40 ng/L. The insecticides imidacloprid, thiacloprid, chlorpyrifos and acetamiprid and the herbicide terbuthylazine exceeded at least once their EQS 58-fold (EQS 13 ng/L), 12-fold (EQS 10 ng/L), 9-fold (EQS 0.46 ng/L), 5-fold (EQS 24 ng/L) and 3-fold (EQS 220 ng/L), respectively. Our study substantially widens the view on pesticide pollution in surface water compared to previous studies in Sub-Saharan Africa by targeting more than 200 pesticides using passive sampling systems. This broad assessment revealed the presence of 53 compounds, some of them in high concentrations, indicating possible adverse effects on biota and the quality of the ecosystem. Whether the observed concentration levels in the year 2017 were exceptional due to the lowest ever recorded rainfall and river discharge needs to be tested with additional data to better understand how pesticide pollution levels manifest under average rainfall and river discharge conditions.

Iron turning waste media for treating Endosulfan and Heptachlor contaminated water

This study explored the application of iron turning waste for the degradation of heptachlor and endosulfan. In batch experiments, 2.5 g of iron turning waste efficiently removed 96% of heptachlor and 85% of endosulfan in 200 mL of water (20 μg/L for each pesticide) in ten minutes. By increasing the iron turning dose from 1 g to 2.5 g, pseudo second order removal rates of heptachlor and endosulfan increased 1.5-fold and 1.37-fold, respectively. Among the minerals in groundwater, calcium and potassium lowered heptachlor removal (8-10%), whereas their effect on endosulfan removal was minimal. Endosulfan removal increased 16%, when water pH was raised from 4 to 10. The effect of water pH on heptachlor removal was minimal. The removal of heptachlor and endosulfan dropped to 55% and 46%, respectively, when the initial concentration was 1 μg/L. In a continuous flow system, iron turning worked better in combination with sand media. Water flow rate (5-15 mL/min) had a limited effect on the removal of both pesticides (initial concentration of 2 μg/L) which increased with increasing iron turning dose (100-150 g) for endosulfan. Heptachlor removal remained stable (100%) regardless of the iron turning amount (100-150 g) used in a filtration column. Iron turning based filter completely removed heptachlor throughout the filtration period (600 h), whereas endosulfan removal dropped from 100% to 88-90% after 300 h. Endosulfan and heptachlor were degraded into nonanal and heptanal, respectively. Iron turning waste was characterized using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) before and after its reactions with both pesticides. XRD and XPS analyses revealed that virgin iron turning waste consisted of zerovalent iron (Fe⁰) and iron oxides, and Fe⁰ was transformed to magnetite (Fe₃O₄) after reacting with both pesticides. Based on detected degradation by-products, the removal mechanism and degradation pathways for both pesticides were elucidated.

Comparing Thresholding with Machine Learning Classifiers for Mapping Complex Water

Small reservoirs play an important role in mining, industries, and agriculture, but storage levels or stage changes are very dynamic. Accurate and up-to-date maps of surface water storage and distribution are invaluable for informing decisions relating to water security, flood monitoring, and water resources management. Satellite remote sensing is an effective way of monitoring the dynamics of surface waterbodies over large areas. The European Space Agency (ESA) has recently launched constellations of Sentinel-1 (S1) and Sentinel-2 (S2) satellites carrying C-band synthetic aperture radar (SAR) and a multispectral imaging radiometer, respectively. The constellations improve global coverage of remotely sensed imagery and enable the development of near real-time operational products. This unprecedented data availability leads to an urgent need for the application of fully automatic, feasible, and accurate retrieval methods for mapping and monitoring waterbodies. The mapping of waterbodies can take advantage of the synthesis of SAR and multispectral remote sensing data in order to increase classification accuracy. This study compares automatic thresholding to machine learning, when applied to delineate waterbodies with diverse spectral and spatial characteristics. Automatic thresholding was applied to near-concurrent normalized difference water index (NDWI) (generated from S2 optical imagery) and VH backscatter features (generated from S1 SAR data). Machine learning was applied to a comprehensive set of features derived from S1 and S2 data. During our field surveys, we observed that the waterbodies visited had different sizes and varying levels of turbidity, sedimentation, and eutrophication. Five machine learning algorithms (MLAs), namely decision tree (DT), k-nearest neighbour (k-NN), random forest (RF), and two implementations of the support vector machine (SVM) were considered. Several experiments were carried out to better understand the complexities involved in mapping spectrally and spatially complex waterbodies. It was found that the combination of multispectral indices with SAR data is highly beneficial for classifying complex waterbodies and that the proposed thresholding approach classified waterbodies with an overall classification accuracy of 89.3%. However, the varying concentrations of suspended sediments (turbidity), dissolved particles, and aquatic plants negatively affected the classification accuracies of the proposed method, whereas the MLAs (SVM in particular) were less sensitive to such variations. The main disadvantage of using MLAs for operational waterbody mapping is the requirement for suitable training samples, representing both water and non-water land covers. The dynamic nature of reservoirs (many reservoirs are depleted at least once a year) makes the re-use of training data unfeasible. The study found that aggregating (combining) the thresholding results of two SAR and multispectral features, namely the S1 VH polarisation and the S2 NDWI, respectively, provided better overall accuracies than when thresholding was applied to any of the individual features considered. The accuracies of this dual thresholding technique were comparable to those of machine learning and may thus offer a viable solution for automatic mapping of waterbodies.

Accurate and Sensitive Determination Method for Procymidone and Chlorflurenol in Municipal Wastewater, Medical Wastewater and Irrigation Canal Water by GC-MS After Vortex Assisted Switchable Solvent Liquid Phase Microextraction

In this study, the detection power of a gas chromatography mass spectrometer (GC-MS) for procymidone and chlorflurenol was significantly enhanced using switchable solvent liquid phase microextraction (SS-LPME) as a preconcentration tool. This was achieved by a comprehensive optimization of significant parameters to the SS-LPME method such as switchable solvent amount, concentration and amount of sodium hydroxide, pH effect and mixing effect. The optimum experimental conditions obtained were used to determine analytical figures of merit for the analytes. The limits of detection obtained were 0.44 and 2.9 ng/mL for procymidone and chlorflurenol, respectively. The optimum method was applied to water sampled from an irrigation canal and two wastewater samples. The samples were spiked at two concentrations and the percent recovery results obtained ranged between 86 and 115% for both analytes. The recovery results together with the low standard deviations recorded validated the method as accurate and precise.

A prospective cohort study of school-going children investigating reproductive and neurobehavioral health effects due to environmental pesticide exposure in the Western Cape, South Africa: study protocol

BACKGROUND

Research on reproductive health effects on children from low-level, long-term exposure to pesticides currently used in the agricultural industry is limited and those on neurobehavioral effects have produced conflicting evidence. We aim at investigating the association between pesticide exposure on the reproductive health and neurobehavior of children in South Africa, by including potential relevant co-exposures from the use of electronic media and maternal alcohol consumption.

METHODS

The design entails a prospective cohort study with a follow-up duration of 2 years starting in 2017, including 1000 school going children between the ages of 9 to 16 years old. Children are enrolled with equal distribution in sex and residence on farms and non-farms in three different agricultural areas (mainly apple, table grapes and wheat farming systems) in the Western Cape, South Africa. The neurobehavior primary health outcome of cognitive functioning was measured through the iPad-based CAmbridge Neuropsychological Test Automated Battery (CANTAB) including domains for attention, memory, and processing speed. The reproductive health outcomes include testicular size in boys and breast size in girls assessed in a physical examination, and blood samples to detect hormone levels and anthropometric measurements. Information on pesticide exposure, co-exposures and relevant confounders are obtained through structured questionnaire interviews with the children and their guardians. Environmental occurrence of pesticides will be determined while using a structured interview with farm owners and review of spraying records and collection of passive water and air samples in all three areas. Pesticide metabolites will be analysed in urine and hair samples collected from the study subjects every 4 months starting at baseline.

DISCUSSION

The inclusion of three different agricultural areas will yield a wide range of pesticide exposure situations. The prospective longitudinal design is a further strength of this study to evaluate the reproductive and neurobehavioural effects of different pesticides on children. This research will inform relevant policies and regulatory bodies to improve the health, safety and learning environments for children and families in agricultural settings.

Polar pesticide contamination of an urban and peri-urban tropical watershed affected by agricultural activities (Yaoundé, Center Region, Cameroon)

Urban agriculture is crucial to local populations, but the risk of it contaminating water has rarely been documented. The aim of this study was to assess pesticide contamination of surface waters from the Méfou watershed (Yaoundé, Cameroon) by 32 selected herbicides, fungicides, and insecticides (mainly polar) according to their local application, using both grab sampling and polar organic compounds integrative samplers (POCIS). Three sampling campaigns were conducted in the March/April and October/November 2015 and June/July 2016 rainy seasons in urban and peri-urban areas. The majority of the targeted compounds were detected. The quantification frequencies of eight pesticides were more than 20% with both POCIS and grab sampling, and that of diuron and atrazine reached 100%. Spatial differences in contamination were evidenced with higher contamination in urban than peri-urban rivers. In particular, diuron was identified as an urban contaminant of concern because its concentrations frequently exceeded the European water quality guideline of 0.200 μg/L in freshwater and may thus represent an ecological risk due to a risk quotient > 1 for algae observed in 94% of grab samples. This study raises concerns about the impacts of urban agriculture on the quality of water resources and to a larger extent on the health of the inhabitants of cities in developing countries. Graphical abstract ᅟ.

Acute exposure to the penconazole-containing fungicide Topas partially augments antioxidant potential in goldfish tissues

Penconazole is a systemic fungicide commonly used in agriculture as the commercial preparation Topas. Although triazole fungicides are widely found in the aquatic environment, little is known about their acute toxicity on fish. In this study we assessed the effects of short-term exposure to Topas on some parameters of homeostasis of reactive oxygen species (ROS), such as the levels of markers of oxidative stress and parameters of the antioxidant defense system of goldfish (Carassius auratus L.). Gills appeared to be the main target organ of Topas toxicity, showing the greatest number of parameters affected. Gills of Topas-treated fish showed a higher content of low (L-SH) and high (H-SH) molecular mass thiols and higher activities of superoxide dismutase (SOD), catalase, glutathione reductase (GR), glutathione-S-transferase (GST), and glucose-6-phosphate dehydrogenase (G6PDH) as well as reduced carbonyl protein content (CP), as compared with those in the control group. In the liver, goldfish exposure to 15-25mgL^-1 Topas resulted in a higher L-SH and H-SH content, but lower CP levels and activity of GST. In kidney, Topas exposure resulted in higher activities of glutathione peroxidase (GPx) and G6PDH, but lower L-SH content and activity of GST. The results of this study indicate that acute goldfish exposure to the triazole fungicide Topas increased efficiency of the antioxidant system in fish gills, liver, and kidney. This could indicate the development of low intensity oxidative stress which up-regulates defense mechanisms responsible for protection of goldfish against deleterious ROS effects.

Pesticide Residue Monitoring on South African Fresh Produce Exported over a 6-Year Period

Six years of pesticide residue data from fresh produce destined for the export market were analyzed for the period 2009 to 2014. A total of 37,838 fruit (99.27%) and vegetable (0.73%) data sets analyzed for the presence of 73 pesticides were compared. Pesticides were detected on 56.46% of samples, of which 0.78% had multiple residues. Noncompliances detected were because of the use of unregistered pesticides (0.73%), values that exceeded established maximum residue levels (MRLs) (0.32%), or the combination of values that exceeded MRLs and the use of unregistered pesticide residues (0.003%). The most commonly detected pesticides that exceeded established MRLs were imazalil (37.71%), prochloraz (28.69%), and iprodione (5.74%). The unregistered pesticide most often found on grapes and avocados was also imazalil (62.23%) and, on nectarines and avocados, diphenylamine (11.15%). Exceedances of MRL values were mostly associated with oranges (43.44%), avocados (27.87%), grapefruits (7.38%), and lemons (6.56%). Residual pesticide monitoring on fruits and vegetables is a key tool to ensure conformity with regulatory requirements and compliance with good agricultural practices and the trade requirements set by the importing country.

Mechanism of action of endosulfan as disruptor of gonadal steroidogenesis in the cichlid fish Cichlasoma dimerus

The organochlorine pesticide endosulfan (ES) is used in several countries as a wide spectrum insecticide on crops with high commercial value. Due to its high toxicity to non-target animals, its persistence in the environment and its ability to act as an endocrine disrupting compound in fish, ES use is currently banned or restricted in many other countries. Previous studies on the cichlid fish Cichlasoma dimerus have shown that waterborne exposure to ES can lead to both decreased pituitary FSH content and histological alterations of testes. As gonadotropin-stimulated sex steroids release from gonads was inhibited by ES in vitro, the aim of the present study was to elucidate possible mechanisms of disruption of ES on gonadal steroidogenesis in C. dimerus, as well as compare the action of the active ingredient (AI) with that of currently used commercial formulations (CF). Testis and ovary fragments were incubated with ES (AI or CF) and/or steroidogenesis activators or precursors. Testosterone and estradiol levels were measured in the incubation media. By itself, ES did not affect hormone levels. Co-incubation with LH and the adenylate cyclase activator forskolin caused a decrease of the stimulated sex steroids release. When co-incubated with precursors dehydroandrostenedione and 17αhydroxyprogesterone, ES did not affect the increase caused by their addition alone. No differences were observed between the AI and CFs, suggesting that the effect on steroidogenesis disruption is mainly caused by the AI. Results indicate that action of ES takes place downstream of LH-receptor activation and upstream of the studied steroidogenic enzymes.

Low-Dose Methylmercury-Induced Apoptosis and Mitochondrial DNA Mutation in Human Embryonic Neural Progenitor Cells

Methylmercury (MeHg) is a long-lasting organic pollutant primarily found in the aquatic environment. The developing brain is particularly sensitive to MeHg due to reduced proliferation of neural stem cell. Although several mechanisms of MeHg-induced apoptosis have been defined in culture models, it remains unclear whether mitochondrial DNA (mtDNA) mutation is involved in the toxic effect of MeHg, especially in the neural progenitor cells. In the present study, the ReNcell CX cell, a human neural progenitor cells (hNPCs) line, was exposed to nanomolar concentrations of MeHg (≤50 nM). We found that MeHg altered mitochondrial metabolic function and induced apoptosis. In addition, we observed that MeHg induced ROS production in a dose-dependent manner in hNPCs cells, which was associated with significantly increased expressions of ND1, Cytb, and ATP6. To elucidate the mechanism underlying MeHg toxicity on mitochondrial function, we examined the ATP content and mitochondrial membrane potential in MeHg-treated hNPCs. Our study showed that MeHg exposure led to decreased ATP content and reduced mitochondrial membrane potential, which failed to match the expansion in mtDNA copy number, suggesting impaired mtDNA. Collectively, these results demonstrated that MeHg induced toxicity in hNPCs through altering mitochondrial function and inducing oxidative damage to mtDNA.

Regional Variation in Human Exposure to Persistent Organic Pollutants in the United States, NHANES

We examined serum levels of persistent organic pollutants (POPs) among geographical regions of the United States as defined by the US Census Bureau. National Health and Nutrition Examination Survey (NHANES) data for adults aged 20 years and older are presented for selected survey periods between 1999 and 2010. From NHANES 1999 through 2004, dichlorodiphenyldichloroethylene (DDE) concentration levels were consistently higher among people living in the West than in the Midwest, Northeast, or South. In 2003-2010, perfluorinated compound concentrations tended to be highest in the South. The sum of 35 polychlorinated biphenyls (PCBs) congeners was significantly higher in the Northeast [GM: 189; 95% CI: 173-204 ng/g lipid] than the remaining regions. The regional differences in higher body burdens of exposure to particular POPs could be attributed to a variety of activities, including region-specific patterns of land use and industrial and agricultural chemical applications, as well as different levels of regulatory activity.

Differential uptake of endosulfan in the South American toad under sublethal exposure

Agroecosystems are usually polluted with a wide variety of contaminants with pesticides being very frequently detected. Endosulfan, an organochlorine pesticide, has been shown to cause both lethal and sublethal effects on aquatic organisms such as amphibians and especially on its early developmental stages. In this context, the aim of this study was to evaluate the uptake of environmentally relevant concentrations of endosulfan and its correlation with differential sensitivity in the early development stages of the common South American toad, Rhinella arenarum. Embryos and larvae were exposed to sublethal concentrations of endosulfan for several periods of exposures. According to the developmental stage at which they were exposed, the uptake rate was different. Bioconcentration factors (BCFs) for embryos significantly decreased with exposure time and concentration (p < 0.05) reaching a BCF of ≤1679 for embryos at 96 h of exposure to 0.001 mg endosulfan L(-1). BCFs for larvae significantly increased with exposure time (p < 0.05) obtaining a maximum of 40 at 504 h. In our previous study, we reported that embryos were less sensitive to the effects of endosulfan than larvae, which is in line with the main tendency of embryos to bioconcentrate endosulfan as observed in this study.

Asthma associated with pesticide exposure among women in rural Western Cape of South Africa

BACKGROUND

Few studies have investigated asthma and pesticides among women farm workers in developing countries.

METHODS

A cross-sectional study was conducted to investigate the association between pesticides and asthma among rural women (n = 211). Outcome measurements included respiratory symptoms (European Community Respiratory Health Survey questionnaire), immunological status (Phadiatop, serum IgE to mite allergens) and lower airway inflammation (fractional exhaled nitric oxide (FeNO) levels). Exposure variables included self-reported pesticide exposure and whole blood cholinesterase (ChE).

RESULTS

The prevalence of ocular-nasal symptoms (ONS), doctor-diagnosed asthma and current asthma was 24%, 11%, and 6% respectively. ONS was positively associated with re-entering a sprayed field (OR = 2.97; CI: 0.93-9.50). Asthma symptom score was associated with low ChE (OR = 1.93; CI: 1.09-3.44). Participants with high FeNO (>50 ppb) also had an elevated odds of having low ChE (OR = 4.8; CI: 0.80-28.00).

CONCLUSION

Pesticide exposure among women farm workers is associated with increased risk of ocular nasal symptoms and an elevated asthma symptom score.

Toxicity of endosulfan on embryo-larval development of the South American toad Rhinella arenarum

Endosulfan is a widely used pesticide despite its extreme toxicity to a variety of taxa and its worldwide ban. The aim of the present study was to evaluate the acute and chronic toxicity of endosulfan on the embryonic-larval development of the common South American toad Rhinella arenarum. The results showed that lethal and sublethal effects increased with concentration and exposure time. The sensitivity to endosulfan increased during the larval period, the complete operculum stage (S.25) being the most sensitive (504-h median lethal concentration [LC50] = 0.01 mg endosulfan/L; 10% lethal concentration [LC10] = 0.004 mg endosulfan/L). Endosulfan exposure caused morphological abnormalities such as general underdevelopment, edema, gill malformations, and cellular dissociation as well as neurotoxicity. Our results also showed that larvae exposed to concentrations of 0.005 mg endosulfan/L and 0.01 mg endosulfan/L completed metamorphosis earlier than controls, but with underdevelopment. The 240-h teratogenic index was 6.13, implying a high risk for embryos to be malformed in the absence of significant embryonic lethality. Because the hazard quotients for chronic exposure were over 1, the level of concern value and toxicity endpoints obtained in the present study for R. arenarum occurred at concentrations lower than the levels of endosulfan reported in the environment, this pesticide should be considered a potential risk for this species.

Prioritizing agricultural pesticides used in South Africa based on their environmental mobility and potential human health effects

South Africa is the largest user of pesticides in sub-Saharan Africa and many studies have highlighted the occurrence of pesticides in water resources. Poor management of water treatment facilities in combination with a relatively high dependency on untreated water from boreholes and rivers creates the potential for exposure of human communities to pesticides and their associated health effects. Pesticide use, physicochemical and toxicity data was therefore used to prioritize pesticides in terms of their potential risk to human health. After eliminating pesticides used in very low quantities, four indices were used to prioritize active ingredients applied in excess of 1000 kg per annum; the quantity index (QI) which ranked pesticides in terms of the quantity of their use; the toxicity potential index (TP) which ranked pesticides according to scores derived for their potential to cause five health effects (endocrine disruption, carcinogenicity, teratogenicity, mutagenicity and neurotoxicity); hazard potential index (HP) which multiplied the TP by an exposure potential score determined by the GUS index for each pesticide (to provide an indication of environmental hazard); and weighted hazard potential (WHP), which multiplied the HP for a pesticide by the ratio of its use to the total use of all pesticides in the country. The top 25 pesticides occurring in each of these indices were identified as priority pesticides, resulting in a combined total of 69 priority pesticides. A principal component analysis identified the indices that were most important in determining why a specific pesticide was included in the final priority list. As crop specific application pesticide use data was available it was possible to identify crops to which priority pesticides were applied to. Furthermore it was possible to prioritize crops in terms of the specific pesticide applied to the crop (by expressing the WHP as a ratio of the total amount of pesticide applied to the crop to the total use of all pesticides applied in the country). This allows for an improved spatial assessment of the use of priority pesticides. The methodology applied here provides a first level of basic, important information that can be used to develop monitoring programmes, identify priority areas for management interventions and to investigate optimal mitigation strategies.

Activation of the NF κ B Pathway Enhances AhR Expression in Intestinal Caco-2 Cells

Recent data suggest that apart from its well-known role in the regulation of xenobiotic metabolizing enzymes, AhR is also involved in inflammation. However, the influence of inflammation on AhR expression remains unknown. Here, we demonstrated that proinflammatory conditions induced by either PMA or IL-1 β enhance AhR expression in Caco-2 cells. This was associated with an increase in AhR promoter activity. By means of directed mutagenesis experiments and the use of proteasome inhibitors, we demonstrated that inflammation-induced AhR expression involved the NF κ B pathway but not AP-1. Moreover, conditioned media from PMA-treated Caco-2 cells were also able to induce AhR expression, and this induction was repressed by anti-IL-1 β blocking antibodies. Similar results were obtained with conditioned media from PMA-treated THP-1 cells. Taken together, these data suggest that AhR could be involved in vivo in an inflammatory loop. AhR was recently suspected to be implicated in inflammatory bowel disease. Our results support this hypothesis and suggest that AhR could be a new target for inflammatory bowel disease patient management.

Endosulfan effects on Rana dalmatina tadpoles: quantitative developmental and behavioural analysis

Endosulfan is an organochlorine pesticide that was recently labeled as a persistent organic pollutant, but it is still widely employed, particularly in developing countries. The goal of this study is to evaluate the acute (LC(50)) and chronic effects (developmental and behavioural traits) of this insecticide on Rana dalmatina tadpoles after exposure to ecologically relevant concentrations (0.005, 0.01, and 0.05 mg/L) by applying video-tracking techniques to evaluate the quantitative effect of endosulfan on amphibian behavioural patterns. The 96 h LC(50) value was 0.074 mg endosulfan/L. Tadpoles chronically exposed to 0.01 and 0.05 mg endosulfan/L underwent high mortality rate, decreased larval growth, delayed development, and increased incidence of malformations, and they did not reach metamorphosis by the end of the experiment. Moreover, tadpoles exposed to these concentrations exhibited several abnormalities in swimming patterns, such as shorter distance moved, swirling, resting, and unusual use of space. The exposure to 0.005 mg endosulfan/L did not cause any significant effects on behaviour, larval growth, or development, but we observed a significant decrease in both survival and time to metamorphosis. We showed that developmental abnormalities are dose-dependent and that the pesticide effects could differ depending on the endosulfan concentration and the species tested. We also validated the hypothesis that behavioural analysis, along with the use of new analytical methods, could be a useful tool in amphibian ecotoxicological studies.

Endocrine disruptive potential of endosulfan on the reproductive axis of Cichlasoma dimerus (Perciformes, Cichlidae)

Endosulfan (ES), a persistent organochlorine pesticide, is widely used despite its toxicity to non-target animals. Upon reaching water bodies, ES can cause negative effects on aquatic animals, including disruption of hormonal systems. However, the action of ES on fish reproductive axis has been hardly studied thus far. The aim of the present work was to assess the endocrine disruptive potential of endosulfan on the pituitary gonadotropins levels and on the testes function due to ES in the South American freshwater fish Cichlasoma dimerus, using in vitro and in vivo approaches. In vitro experiments showed that ES inhibited the LH-stimulated steroidogenesis in gonads; no change was observed in gonadotropins release from pituitaries in culture. Laboratory waterborne ES (0.1, 0.3 and 1 μg/L) exposure for two months caused decrease in βFSH pituitary content and γGT activity in the testes (Sertoli cell function marker). Testicular histology revealed pathologies such as scarce intermediate stages of spermatogenesis, release of immature germ cells into the lobular lumen, presence of foam cells and interstitial fibrosis. As FSH and FSH-mediated steroidogenesis regulate spermatogenesis and Sertoli cell function, the effect of ES on FSH could be responsible for the morphological alterations observed in testes. In vitro, ES disrupted steroidogenesis in gonads, therefore similar effects in vivo cannot be ruled out. Based on this evidence, ES exhibits an endocrine disruptive action on the reproductive axis of C. dimerus, causing disruption at the pituitary and/or at the gonad level. These effects could acquire ecological significance under prolonged exposure to the pesticide in nature.

Farm residence and reproductive health among boys in rural South Africa

BACKGROUND

Few studies have investigated reproductive health effects of contemporary agricultural pesticides in boys.

OBJECTIVES

To determine the association between pesticide exposure and reproductive health of boys.

METHODS

We conducted a cross-sectional study in rural South Africa of boys living on and off farms. The study included a questionnaire (demographics, general and reproductive health, phyto-estrogen intake, residential history, pesticide exposures, exposures during pregnancy); and a physical examination that included sexual maturity development ratings; testicular volume; height, weight, body mass index; and sex hormone concentrations.

RESULTS

Among the 269 boys recruited into the study, 177 (65.8%) were categorized as farm (high pesticide exposures) and 98 (34.2%) as non-farm residents (lower pesticide exposures). Median ages of the two groups were 11.3 vs 12.0 years, respectively (p<0.05). After controlling for confounders that included socioeconomic status, farm boys were shorter (regression coefficient (RC)=-3.42 cm; 95% confidence interval (CI): -6.38 to -0.45 cm) and weighed less (RC=-2.26 kg; CI: -4.44 to -0.75 kg). The farm boys also had lower serum lutenizing hormone (RC=-0.28 IU/L; CI: -0.48 to -0.08 IU/L), but higher serum oestradiol (RC=8.07 pmol/L; CI: 2.34-13.81 pmol/L) and follicle stimulating hormone (RC=0.63 IU/L; CI: 0.19-1.08 U/L).

CONCLUSIONS

Our study provides evidence that farm residence is associated with adverse growth and reproductive health of pubertal boys which may be due to environmental exposures to hormonally active contemporary agricultural pesticides.

Methyl mercury exposure at Niigata, Japan: results of neurological examinations of 103 adults

Background. Large-scale poisonings caused by methyl mercury (MeHg) have occurred in Japan (Minamata in the 1950s and Niigata in the 1960s) and Iraq (in the 1970s). The current WHO neurological risk standard for adult exposure (hair level: 50 μg/g) was based partly on evidence from Niigata which did not consider any cases who were diagnosed later and/or exposed to low level of MeHg (hair mercury level less than 50 μg/g). Methods. Early in the Niigata epidemic in June 1965 there were two extensive surveys. From these two surveys, we examined 103 adults with hair mercury measurement who consulted two medical institutions. We compared the prevalence and the distribution of neurological signs related to MeHg poisoning between exposure categories. Result. We found 48 subjects with neurological signs related to MeHg poisoning who had hair mercury concentration less than 50 μg/g. Among the neurological signs, sensory disturbance of the bilateral distal extremities was observed more frequently, followed by disequilibrium, hearing impairment, and ataxia, in groups with hair MeHg concentration both below 50 μg/g and over 50 μg/g. Conclusion. The present study suggests the possibility that exposure to MeHg at levels below the current WHO limits could cause neurologic signs, in particular, sensory disturbance.

The prevalence of cardiovascular disease risk factors and obesity in firefighters

Obesity is associated with increased risk of cardiovascular disease (CVD) mortality. CVD is the leading cause of duty-related death among firefighters, and the prevalence of obesity is a growing concern in the Fire Service. Methods. Traditional CVD risk factors, novel measures of cardiovascular health and a measurement of CVD were described and compared between nonobese and obese career firefighters who volunteered to participate in this cross-sectional study. Results. In the group of 116 men (mean age 43 ± 8 yrs), the prevalence of obesity was 51.7%. There were no differences among traditional CVD risk factors or the coronary artery calcium (CAC) score (criterion measure) between obese and nonobese men. However, significant differences in novel markers, including CRP, subendocardial viability ratio, and the ejection duration index, were detected. Conclusions. No differences in the prevalence of traditional CVD risk factors between obese and nonobese men were found. Additionally, CAC was similar between groups. However, there were differences in several novel risk factors, which warrant further investigation. Improved CVD risk identification among firefighters has important implications for both individual health and public safety.