Health Risk Assessment Framework Research Articles

Leveraging Mobile Technology for Enhanced Mental Health Levels in University Students

With the advent of the digital era, the application of mobile technology in higher education has become increasingly prevalent, particularly in the management of students’ mental health. University students face multiple pressures, including academic, social, and career-related challenges, which have led to a rise in mental health issues. As a result, the utilization of mobile technology to collect and analyze students’ mental states and behavioral data in realtime has emerged as significant research focus. Current studies predominantly rely on traditional survey methods, which fail to capture students’ dynamic mental states in real-time and often lack an in-depth understanding of complex behavioral patterns. Moreover, few existing studies have examined the integration of multi-source data, thereby limiting comprehensive analyses of mental health risks. This study proposes a dynamic mental behavior inference and mental health risk assessment framework for university students based on multi-source data integration. The framework aims to analyze students’ mental health conditions comprehensively by integrating diverse data from mobile technology. Experimental results and analyses were presented to verify the framework’s effectiveness and practicality, providing new insights for mental health management in higher education and laying the foundation for future research.

Selective enrichment of high-risk antibiotic resistance genes and priority pathogens in freshwater plastisphere: Unique role of biodegradable microplastics

Microplastics (MPs) has been concerned as emerging vectors for spreading antibiotic resistance and pathogenicity in aquatic environments, but the role of biodegradable MPs remains largely unknown. Herein, field in-situ incubation method combined with metagenomic sequencing were employed to reveal the dispersal characteristics of microbial community, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and virulence factors (VFs) enriched by MPs biofilms. Results showed that planktonic microbes were more prone to enrich on biodegradable MPs (i.e., polyhydroxyalkanoate and polylactic acid) than non-biodegradable MPs (i.e., polystyrene, polypropylene and polyethylene). Distinctive microbial communities were assembled on biodegradable MPs, and the abundances of ARGs, MGEs, and VFs on biofilms of biodegradable MPs were much higher than that of non-biodegradable MPs. Notably, network analysis showed that the biodegradable MPs selectively enriched pathogens carrying ARGs, VFs and MGEs concurrently, suggesting a strong potential risks of co-spreading antibiotic resistance and pathogenicity through horizontal gene transfer. According to WHO priority list of Antibiotic Resistant Pathogens (ARPs) and ARGs health risk assessment framework, the highest abundances of Priority 1 ARPs and Rank I risk ARGs were found on polylactic acid and polyhydroxyalkanoate, respectively. These findings elucidate the unique and critical role of biodegradable MPs for selective enrichment of high-risk ARGs and priority pathogens in freshwater environments.

Which organic contaminants should be paid more attention: Based on an improved health risk assessment framework

The increasing chemical pollution of the drinking water is widely concerned. Large number of organic contaminants cannot be removed by conventional water treatment technology due to their low concentration, and long-term exposure may pose significant risks to human health. Which organic contaminants in drinking water should be given more attention has been a topic of great concern in recent years. To identify the organic contaminants that need attention, this research proposes an improved health risk screening method to quantitatively analyze the risks of accumulation, persistence, toxicity, and antibiotic resistance. Compared with conventional method, 26 compounds were added to the improved screening list, including 9 DBPs (e.g., NDMA), 3 antibiotics (e.g., oxytetracycline), PFNA and other compounds. Overall, antibiotics and plasticizers rose in the risk rankings. From the perspective of the proportion of total risk value, a single risk plays a decisive role (more than 99%) in the ranking. This change suggests that antibiotic resistance and the accumulation of organic matter are as important as their toxic risks to humans. 58 compounds were recommended for the priority control organic contaminants list in drinking water. This list provides the necessary information for authoritative regulations to monitor, control, assess, and manage the risks of environmentally relevant compounds in drinking water in China.

The Role of Wastewater Treatment Plants in Dissemination of Antibiotic Resistance: Source, Measurement, Removal and Risk Assessment.

Antibiotic Resistance Genes (ARGs) are contaminants of emerging concern with marked potential to impact public and environmental health. This review focusses on factors that influence the presence, abundance, and dissemination of ARGs within Wastewater Treatment Plants (WWTPs) and associated effluents. Antibiotic-Resistant Bacteria (ARB) and ARGs have been detected in the influent and the effluent of WWTPs worldwide. Different levels of wastewater treatment (primary, secondary, and tertiary) show different degrees of removal efficiency of ARGs, with further differences being observed when ARGs are captured as intracellular or extracellular forms. Furthermore, routinely used molecular methodologies such as quantitative polymerase chain reaction or whole genome sequencing may also vary in resistome identification and in quantifying ARG removal efficiencies from WWTP effluents. Additionally, we provide an overview of the One Health risk assessment framework, as well as future strategies on how WWTPs can be assessed for environmental and public health impact.

Risk assessment of influenza transmission between workers and pigs on US indoor hog growing units

On pig farms ample opportunity exists for pig-to-human and human-to-pig (cross-species) influenza transmission. The purpose of this study was to assess the risks of cross-species influenza transmission within an indoor pig grower unit in the United States and to prioritize data gaps. Using the World Organization for Animal Health risk assessment framework we evaluated influenza transmission across two risk pathways: 1. What is the likelihood that based on current conditions on a single typical hog grower-finisher facility in the Midwest (US), during a single production cycle, at least one hog becomes infected with an influenza virus associated with swine (either H1N1, H3N2, or H1N2) [step 1a] and that at least one worker becomes infected as a result [step 1b] and that the worker develops symptoms [step 1c]? And 2. What is the likelihood that, based on current conditions on a single typical hog grower-finisher facility in the Midwest (US), during a single production cycle, at least one worker becomes infected with an influenza virus associated with people (either H1N1, H3N2, or H1N2) [step 2a] and that at least one pig becomes infected as a result [step 2b] and that the pig(s) develop(s) symptoms [step 2c]?Semi-quantitative probability and uncertainty assessments were based on literature review including passive and active influenza surveillance data. We assumed a typical pig-grower farm has capacity for 4,000 pigs, two workers, and minimal influenza control measures. Probability and uncertainty categories were assessed for each risk step and the combined risk pathway.The combined risk assessment for risk pathway one was estimated to be Very Low for H1N1 and H1N2 with an overall High level of uncertainty. The combined risk assessment for risk pathway two was estimated to be Extremely Low for H1N1 and H3N2 with a High degree of uncertainty. Scenario analyses in which influenza control measures were assumed to be implemented separately (implementing vaccinating sows, mass vaccinating incoming pigs or improved personal protective equipment adherence) showed no reduction in the combined risk category. When implementing three influenza control methods altogether, the combined risk could be reduced to Extremely Low for risk pathway one and remained Extremely Low for risk pathway two. This work highlights that multiple influenza control methods are needed to reduce the risks of inter-species influenza transmission on swine farms.

Dynamic risk assessment of re-construction dust from abandoned industrial buildings: A human-dust interaction perspective

Health risk assessment (HRA) is a well-established and widely used tool for quantitatively assessing the health status and likelihood of future illness and death of an individual or group. The dynamic properties of reconstruction dust from abandoned industrial buildings significantly affect HRA results. In recent years, dynamic health risk assessment (DHRA) has become an emerging research field. However, research on DHRA is still in the preliminary stage, and the research and application of its dynamic factors lack systematic analysis. Examining data transformation pathways through the U.S. Environmental Agency (USEPA) standard HRA framework, this study formalizes two distinct elements of dynamic assessment, namely, dynamic construction procedures and dynamic construction behaviour from a human-dust interaction perspective. Then, a DHRA framework for reconstruction dust of abandoned industrial buildings is proposed so that the aforementioned dynamic evaluation factors can be integrated into the HRA framework. Finally, feasible application solutions and data availability of dynamic factors are discussed, and case studies are carried out to better support DHRA application. The results show that the evaluation results are sensitive to different degrees of dynamic evaluation factors, and DHRA can provide more authentic and reliable evaluation results.

Towards evaluating the conditional probability of waterborne microbial risks associated with critical rainfall events following land application of animal waste — A focus on Irish pastures

ABSTRACT Modelling surface runoff and infiltration in an agricultural watershed is essential for understanding the nutrient cycle and water quality management. This research evaluates the critical rainfall events causing maximum surface runoff and infiltration. Empirical models such as Soil Conservation Service (SCS) curve number and Explicit Green-Ampt (EGA) were analysed for different soil hydraulic conditions and storm events with specific return periods. The present study forecasted the maximum daily rainfall and intensity as 113.6 mm and 19.9 cm h–1, respectively, considering a 100-year return period storm. The deterministic part of the model calculates the daily maximum surface runoff as 5.51 cm (from the SCS model). The EGA model revealed that the rainfall intensity of 0.143, 0.163, 0.175, 0.179, 0.181, 0.182, and 0.182 cm h−1 (duration of 24 h) was found critical for 1, 2, 5, 10, 25, 50, 100 year return period of the storm, respectively in different soil texture classes (sand, loamy sand, sandy loam, loam, silt loam, sandy clay loam, clay loam, silty clay soils). Exceptions imply for three occasions where the intensity of 0.407 cm h−1 and duration of 18 h produced maximum infiltration for silty clay loam, and intensity of 0.352 and 0.354 cm h−1 with 9 h rainfall (each) produced maximum infiltration for clay. The probabilistic model revealed that a daily storm event probability of 2.74 × 10–5 is associated with a simulated mean runoff depth of 0.69 cm and infiltration of 20.7 cm. Critical rainfall probabilities calculated in this study can be multiplied with the overall microbial/pollutant human health risk assessment framework to calculate conditional probability and better estimate microbial risk through the drinking water pathway. This study is very relevant for the wet climatic condition of Ireland, where most land use is pastures.

Human health risk assessment framework for new water resource recovery-based bio-composite materials.

A new type of bio-composite material is being produced from water-recovered resources such as cellulose fibres from wastewater, calcite from the drinking water softening process, and grass and reed from waterboard sites. These raw materials may be contaminated with pathogens and chemicals such as Escherichia coli, heavy metals, and resin compounds. A novel risk assessment framework is proposed here, addressing human health risks during the production of new bio-composite materials. The developed framework consists of a combination of existing risk assessment methods and is based on three main steps: hazard identification, qualitative risk mapping, and quantitative risk assessment. The HAZOP and Event Tree Analysis methodologies were used for hazard identification and risk mapping stages. Then, human health risks were quantitatively assessed using quantitative chemical risk assessment, evaluating cancer and non-cancer risk, and quantitative microbial risk assessment. The deterministic and the stochastic approaches were performed for this purpose. The contamination of raw materials may pose human health concerns, resulting in cancer risk above the threshold. Microbial risk is also above the safety threshold. Additional analysis would be significant as future research to better assess the microbial risk in biocomposite production. The framework has been effectively used for chemical and microbial risk assessment.

An integrated human health risk assessment framework for alkylphenols due to drinking water and crops' food consumption

The increasing overexploitation and pollution of freshater resources are potential threats for public health, causing cross-contamination among the interconnected environmental compartments (freshwater, soil, crops). In particular, contaminants of emerging concern (CECs) originating from anthropic activities are not completely removed by wastewater treatments plants. This leads to their presence in drinking water (DW) sources, soil and crops intended for human consumption due to discharges of treated wastewater in surface waters and direct wastewater reuse practices. Currently, health risk assessments are limited to single exposure sources without considering the multiple exposure routes to which humans are subjected. For instance, among CECs, bisphenol A (BPA) and nonylphenol (NP), respectively, adversely affect immune and renal systems and have been frequently detected in DW and food, their major exposure sources for humans. Here, an integrated procedure is proposed to quantitatively assess health risk from CECs due to multiple exposure from the consumption of both DW and food, considering the relevant inter-connected environmental compartments. This procedure was applied to BPA and NP to calculate their probabilistic Benchmark Quotient (BQ), showing its potential in quantitatively apportioning the risk between contaminants and exposure sources, and its use as a decision support tool for prioritizing mitigation measures. Our results indicate that, even though the human health risk due to NP is not negligible, the estimated risk due to BPA is significantly higher, and the consumption of food from edible crops determines a higher risk compared to tap water. Hence, BPA is undoubtedly a contaminant to be prioritized, especially through mitigation actions aimed at its prevention and removal from food.

A health risk matrix for assessing the impacts of heat and cold exposure in residential buildings

• BACKGROUND AND AIM With people in developed countries spending 70% of their time at home, the impact of the built environment on human health is vital. Although there has been ample epidemiological evidence on the relationship between high/low outdoor temperature exposures and adverse health impacts, there is a paucity of research investigating how residential characteristics and human behaviours might affect temperature-related health risks. This research aims to fill this gap. • METHODS A health risk matrix was obtained by applying a four-stage spatiotemporal health risk assessment framework (comprising hazard identification, exposure assessment, exposure-response assessment and risk characterization) to estimate the temperature-cardiovascular mortality relationship in Greater Taipei, Taiwan, using paired observations of outdoor-indoor temperatures and PM2.5 concentrations in dwellings. • RESULTS Residential characteristics and household energy use acted as moderators, and indoor temperature functioned as a mediator in the temperature-mortality relationship. A three-dimensional matrix projected outdoor temperature, human vulnerability and dwelling type along three axes to visualise the cardiovascular mortality risk. Human vulnerability represents the interaction between outdoor temperature and household energy use. By multiplying the risk levels (1-3) of each of the three axes, a total of 27 levels of health risk are obtained. • CONCLUSIONS This study encourages carefully-planned climate change mitigations and adaptations to achieve healthier indoor environments: (1) Strategies for reducing temperature-related cardiovascular mortality should incorporate the energy use for heating/cooling, which may affect human vulnerability and be affected by the household income, prevalence of air conditioning systems, green area, and population rate of older people. (2) Building retrofits for improving energy efficiency should carefully consider dwelling thermal types, which may vary with occupants’ behaviours and cause unintended health consequences when indoor temperature closely follows outdoor temperature and makes dwellings overheat or excessively cold. • KEYWORDS Health risk assessment, Health matrix, Temperature-related mortality, Dwellings, Human behaviours

Illness perception and cardiovascular risk factors in patients with myocardial infarction undergoing percutaneous coronary intervention in Iran

BackgroundKnowing of perception of the illness, and cardiovascular risk factors in patients with myocardial infarction is crucial in engaging in effective secondary prevention. This study aimed to examine illness perception and cardiovascular risk factors in patients with myocardial infarction undergoing percutaneous coronary intervention.MethodsThe participants comprised 131 patients undergoing a first-time percutaneous coronary intervention at a metropolitan, tertiary referral hospital in Tabriz, Iran. The convenience sampling method was employed to select the research sample within a six-month period. The instruments used were as follows: (1) Demographic and health information form, (2) The Brief Illness Perception Questionnaire (3) The Health Risk Assessment framework developed by the Centers for Disease Control and Prevention. The design of the study was descriptive, cross sectional. The continuous variables were analyzed using Independent t-test and analysis of variance (ANOVA); and categorical variables were compared using the chi-square test.ResultsMost participants had a positive family history of cardiovascular disease (54.2%), with 66.4% of participants having at least one cardiovascular risk factor such as diabetes (36.6%) hypertension (32.8%) and dyslipidemia (16%). Most participants were physically inactive (78.6%), about 48.9% were overweight, 34.4% suffered from obesity and 26% were smokers. Illness perception in this study was seen to be high (6.21), with highest scores occurring in the illness control dimension (6.83) and lowest scores occurring in the understanding dimension (3.77). There was a significant relationship between illness perception and physical activity, nutrition, sleep and general health. Direct significant relationships between biometric values (cholesterol, glucose, blood pressure); psychological factors (depression, anxiety and stress) and illness perception were also found to exist.ConclusionsLow scores in two dimensions of illness perception may lead to psychological consequences such as stress, anxiety, and depression. The relationship between illness perception and some risk factors of cardiovascular disease such as physical activity, diet and biometric values, reveal the need for more attention to patient education and counselling.

Health risk assessment of volatile organic compounds exposure among nail salon workers in Vietnam

Purpose The objective of this study is to assess the carcinogen and non-carcinogen risks due to exposure to volatile organic compounds including methyl methacrylate (MMA), benzene, toluene, and xylene among Vietnamese nail salon workers, using probabilistic health risk assessment. Methods This study applied the probabilistic health risk assessment framework to assess the health risk due to exposure to four types of volatile organic compounds among nail salon workers. Forty-two passive personal samples of full-shift female nail workers from 15 salons in Da Nang city were monitored and analyzed by GC-FID in the Thammasat laboratory. Exposure parameters were collected by interviewing nail salon workers. Monte Carlo simulation was used to characterize the risk and its uncertainty. Results The mean of concentrations of MMA, benzene, toluene, and xylene were 20.62, 0.21, 2.49, and 0.58 mg m−3, respectively. The 95th percentile hazard quotients calculated for MMA, benzene, toluene, and xylene were 33.14, 7.49, 0.54, and 2.07, respectively. The 95th percentile lifetime cancer risk for benzene was 198 times higher than the EPA recommendation for cancer risk (10−6). Conclusions Non-cancer risks from exposure to MMA, benzene, and xylene were many times higher than the acceptable limit, which indicated a possible risk of adverse health effects among nail salon workers. Nail salon workers may also be at risk of leukemia or cancer of the blood-forming organs because the cancer risk due to exposure to benzene is higher than the recommended level.

Particulate matter exposure and non-cancerous inhalation health risk assessment of major dumpsites of Owerri metropolis, Nigeria

Numerous particulates are released from the dumpsites in Owerri metropolis and later dispersed to other areas in the environment where they cause adverse health challenges to the inhabitants. To analyze the PM concentrations, field measurements were carried out at seven major dumpsites in Owerri Metropolis. Estimates of the possible health risks as the result of exposure to airborne particulate matter (PM2.5, PM10, etc.) were performed using the United States Environmental Protection Agency (USEPA) human health risk assessment framework. A scenario assessment approach in which normal exposure and worst-case scenario were adopted for acute and chronic exposure periods for infants, children, and adults were carried out. The concentrations of PM2.5 which ranged from 122.30–501.76 μg/m3 at the dumpsites exceeded the WHO 24 hr annual mean maximum exposure limit. The Nigerian National Ambient Air Quality Standard allowable limit for PM10 was exceeded by most of the dumpsites. Hazard quotient > 1 was exceeded for PM 2.5 by nearly all dumpsites and is therefore likely to cause health challenges to people in the vicinity of the dumpsites. The results showed that under monthly conditions, both PM2.5 and PM10 concentration levels at the dumpsites have the potential to cause adverse health effects for infants, children, and adults on acute or chronic bases. Actions should be taken to regulate such PM exposure and to raise public awareness for the inhabitants of the affected areas. In conclusion, regular monitoring is therefore recommended to decrease the ambient particulate matter (PM) concentrations in the study area.

Entropy-Based Analysis of the Impact of Environmentally Sensitive Elements on Groundwater Quality of the Ameka Region of Southeast Nigeria: Medical Geology Implications

Understanding the impact of natural and modified environment on human health is a subject within the scope of medical geology. Ameka and its environs in southeastern Nigeria is known for intensive mining and agricultural activities that frequently predispose water resources to pollution by environmentally sensitive elements (ESEs). The present study analyzed the groundwater quality and associated probabilistic human health risks due to ESEs in Ameka area, using multiple indices and a novel health risk assessment framework, HHRISK. Entropy-weighted water quality index and other geochemical evaluation indices (including pollution index, enrichment factor, index of geoaccumulation, pollution index of groundwater, and quantification of contamination) revealed that all the groundwater samples from hand-dug wells and boreholes were extremely polluted and hence unsuitable for drinking. The HHRISK model was utilized for ingestion and dermal exposure routes assessments. Results showed that all the samples pose very high carcinogenic and non-carcinogenic health risks. With respect to aggregated non-carcinogenic HHRISK, the order of health threat impact of the ESEs for children and adult populations is predicted as Cd > As > Se > Co > Ni > Pb > Mn > Zn > Cu > Fe. However, aggregated cancer risk for both populations followed the trend Ni > Cd > As > Pb. Furthermore, cumulative non-carcinogenic risk (HRQcum) and carcinogenic risk (CRcum) scores (for children and adults) exceeded standard limits in all the samples. However, the scores obtained for the adults were generally lower, implying that the children population is more vulnerable to both non-carcinogenic and carcinogenic health risks. Thus, there is urgent need to adopt environmentally-friendly pollution mitigation measures in the Ameka area.

Influence of kitchen structures on household exposure to firewood-induced volatile organic compounds in Senwabarwana villages

This paper presents the extent to which kitchen structures influence household exposure to firewood-induced volatile organic compounds (VOCs). The sample consisted of 69 firewood users who were conveniently sampled from Senwabarwana Villages. An Integrated Environmental Health Risk Assessment framework (IEHRA) was adopted as the research methods of the current study. The VOC samples were collected from selected priority firewood species used in the study area, namely mushu (Umbrella thorn), mohwelere (red bushwillow), moretshe (Sickle bush), motswiri (Leadwood) and mokgwa (Black monkey thorn). Four VOCs, namely benzene, toluene, ethylbenzene and xylene were analysed from each of the selected plant species. Available literature shows that these VOCs are associated with the kind of common firewood used in the study area. The outcomes of this study reveal that mushu emits the highest concentration of the four selected VOCs, followed by moretshe, mohwelere, mokgwa and motswiri, respectively. The influence of kitchen structural factors such as number and positioning of windows, fireplace or stove type, roofing material and designs, among others on the concentration and indoor dispersion of VOCs was also investigated. Behavioural practices of households during fire making such as opening or closing of doors and windows during cooking, water heating and space heating were also found to influence exposure levels. Consequently, low VOCs emitting firewood species and kitchen structural designs have been confirmed as the key drivers of firewood-induced VOC exposure.

The Jeddah tool. A health risk assessment framework for mass gatherings.

[No Abstract Available].

Health Risk and Resilience Assessment with Respect to the Main Air Pollutants in Sichuan.

Rapid urbanization and industrialization in developing countries have caused an increase in air pollutant concentrations, and this has attracted public concern due to the resulting harmful effects to health. Here we present, through the spatial-temporal characteristics of six criteria air pollutants (PM2.5, PM10, SO2, NO2, CO, and O3) in Sichuan, a human health risk assessment framework conducted to evaluate the health risk of different age groups caused by ambient air pollutants. Public health resilience was evaluated with respect to the risk resulting from ambient air pollutants, and a spatial inequality analysis between the risk caused by ambient air pollutants and hospital density in Sichuan was performed based on the Lorenz curve and Gini coefficient. The results indicated that high concentrations of PM2.5 (47.7 μg m−3) and PM10 (75.9 μg m−3) were observed in the Sichuan Basin; these two air pollutants posed a high risk to infants. The high risk caused by PM2.5 was mainly distributed in Sichuan Basin (1.14) and that caused by PM10 was principally distributed in Zigong (1.01). Additionally, the infants in Aba and Ganzi had high health resilience to the risk caused by PM2.5 (3.89 and 4.79, respectively) and PM10 (3.28 and 2.77, respectively), which was explained by the low risk in these two regions. These regions and Sichuan had severe spatial inequality between the infant hazard quotient caused by PM2.5 (G = 0.518, G = 0.493, and G = 0.456, respectively) and hospital density. This spatial inequality was also caused by PM10 (G = 0.525, G = 0.526, and G = 0.466, respectively), which is mainly attributed to the imbalance between hospital distribution and risk caused by PM2.5 (PM10) in these two areas. Such research could provide a basis for the formulation of medical construction and future air pollution control measures in Sichuan.

Health risk assessment of engine exhaust emissions within Australian ports: a case study of Port of Brisbane

Emissions from ocean-going vessels present a significant health risk to populations surrounding ports and damage the environment. Emissions from ships using heavy fuel oil include substantial amounts of sulphur dioxide, nitrogen oxides, and particulate matter. In order to assess the risk of these emissions, a complete methodology has been developed, based on the Australian Environmental Health Risk Assessment Framework. The method includes a detailed inventory of in-port and at-sea emissions using an activity-based approach applying downwash and near-field areas from first principles equations as well as the air-shed regions from CALPUFF dispersion modeling results for Port of Brisbane in 2013. The final risk values are validated against national and European guidelines. Various health impact assessments, as well as carcinogenic and ecological effects, are discussed in depth. This study offers a significant contribution to developing a baseline measurement of the current state of risk from emissions of the ocean-going vessels visiting the port, and suggests that, given the expected development of many Australian ports in the near future, the need for continual monitoring of shipping emissions is an essential and necessary area of research.

Application of biochar to soils may result in plant contamination and human cancer risk due to exposure of polycyclic aromatic hydrocarbons

Biochars are added to soil to improve agronomic yield. This greenhouse- and field-scale study evaluated polycyclic aromatic hydrocarbon (PAH) contamination in 35 commercial and laboratory-produced biochars, and assessed the effects of biochar amendment of soils on PAH accumulation in vegetables and the risk for cancer. The total and bioavailable PAH concentrations in biochars varied from 638 to 12,347 μg/kg and from below the detection limit (BDL) to 2792 μg/kg, respectively. PAH formation in biochars decreased with increasing production temperature (350–650 °C). Root exudates enhanced PAH release from biochars. The total PAH concentrations in eight edible vegetables growing in biochar-amended soil varied according to biochar and vegetables type from BDL to 565 μg/kg. A health risk assessment framework was integrated with the benzo[a]pyrene toxic equivalency quotient and the incremental lifetime cancer risk (ILCR) to estimate the exposure risk for human beings via ingestion of PAH-contaminated vegetables. The total ILCR for adults was above 10−6, which suggests a risk to human health from direct exposure to PAHs in vegetables grown in biochar-amended soil. These results demonstrate that biochar application may lead to contamination of plants with PAHs, which represents a risk to human health. The PAH levels in biochars produced using different conditions and/or feedstocks need to be evaluated and biochars should be pretreated to remove PAHs before their large-scale agronomic application.

Health risks of exposure to air pollutants among students in schools in the vicinities of coal mines

Air pollution poses a serious threat to human health and the general ecosystem both in South Africa and globally. This is mostly caused by the mining and combustion of fossil fuels, such as coal. There are some known pollutants associated with coal mining and combustion that are emitted into the air, resulting in various health implications that affect children the most as they are the most vulnerable. In this study, the levels of certain air pollutants in schools in the vicinities of coal mines were assessed. A cross-sectional study design was adopted. Five schools were purposively selected for this study. Air samples were collected inside and outside the classrooms of each school. Radiello® passive air samplers were used to measure the levels of sulphur dioxide, nitrogen dioxide and ozone while filter pumps were employed for lead (Pb). Standard laboratory analytical methods were employed for the analysis. Estimates of the possible health risks resulting from exposure to airborne sulphur dioxide, nitrogen dioxide and ozone were performed using the United States Environmental Protection Agency Human Health Risk Assessment framework. The non-cancer risk of sulphur dioxide, nitrogen dioxide and ozone was determined using the hazard quotient. The results of this study revealed that sulphur dioxide, nitrogen dioxide and ozone were detected within and outside the classrooms at various levels. For example, the concentration of sulphur dioxide within the classroom ranged from 3.0 to 38 µg/m3. Outside the classroom, sulphur dioxide levels detected were much higher ranging from 17 to 84 µg/m3. The results of the non-carcinogenic risks from exposure to nitrogen dioxide, sulphur dioxide and ozone via inhalation route were less than 1.0. The elevated levels of these pollutants in the vicinity of schools investigated should be a cause for concern for all the stakeholders in the education sector. Therefore, appropriate measures need to be taken urgently to safeguard the health of the concerned community.