PAH exposure in a Ghanaian population at high risk for aflatoxicosis

Exposure and Public Health Effects of Polycyclic Aromatic Hydrocarbon Compounds in Sub-Saharan Africa: A Systematic Review

BACKGROUND AND AIM

In order to achieve improved global health, environmental health risks that could affect this goal have to be reduced as much as possible. This review thus aimed at determining the exposure levels, health risk assessments, and public health effects of polycyclic aromatic hydrocarbons (PAHs) in sub-Saharan Africa (SSA). This review was developed using guidelines provided for Preferred Reporting Items for Systematic Review and Meta-Analysis. Search was done on Google Scholar, Scopus, and PubMed databases. A study was included if it was carried out in SSA from 2000 to 2020 and written in English language. Fifty-two studies were finally retained and used for the review. Extracted data included the concentrations of 8 selected priority PAHs (including the PAHs prioritized for their carcinogenic potentials), their sources and reported outcomes. In SSA, PAHs exposure has been linked to the use of unprocessed biomass fuels for cooking, release of poorly treated petrochemical effluents into water bodies, and so on. Related public health effects included the occurrence of respiratory, cardiovascular abnormalities, and so on. Others included destruction of natural biodiversity in soil, water, and atmospheric environmental media. Health risk assessments also buttressed the occurrence of these public health effects of PAHs. In SSA, the region is exposed to a substantial amount of PAHs pollution which is associated with deleterious environmental and epidemiological effects. The adoption of healthier forms of energy, a change of attitude to one that favors environmental sustainability, and proper enforcement of environmental regulations are, however, necessary for attaining environmental sanity in SSA.

Remediation of PAH-Contaminated Soil by Combining Surfactant Enhanced Soil Washing and Iron-Activated Persulfate Oxidation Process

There is increasing concern regarding soils contaminated with polycyclic aromatic hydrocarbons (PAHs). In the present study, the remediation of soil spiked with PAHs was explored by the combination of soil washing with sodium dodecyl sulfate (SDS) and subsequent oxidation through persulfate (PS) activated by Fe²⁺, nanoscale zero-valent iron (nZVI), and SiO₂-coated nZVI (SiO₂/nZVI). Results demonstrated that the removal of phenanthrene (PHE), fluoranthene (FLU), and pyrene (PYR) by SDS is an efficient means for soil decontamination. At SDS concentration of 20 g/L, the removal efficiencies of PHE, PYR, and FLU were 37%, 40%, and 44%, respectively. For the degradation of PAHs and SDS in the soil washing effluents, the efficiencies of PS activated with SiO₂/nZVI were not significantly different from those of PS activated with nZVI and Fe²⁺ (p > 0.05). In practice, SiO₂/nZVI is more preferable due to the improved antioxidation and dispersibility. At the dosage of 2 g/L (in the amount of iron) of SiO₂/nZVI, the removal efficiencies of PHE, FLU, PYR, and SDS within 30 min of treatment were 75%, 85%, 87%, and 34%, respectively. The degradation of SDS was much lower than those of PAHs, which facilitated the recycle of SDS. Our findings suggest that PS activated with SiO₂/nZVI is a promising method for the treatment of soil washing effluents containing SDS and PAHs.

Health seeking behaviours among electronic waste workers in Ghana

BACKGROUND

Electronic waste workers are prone to various illnesses and injuries from numerous hazards thus the need for them to seek health care. The aim of this study was to describe health-seeking behavior, and social and other factors affecting this behavior, among electronic waste workers at Agbogbloshie, Accra, Ghana.

METHODS

In-depth interviews were conducted and analyzed qualitatively from a grounded theory perspective.

RESULTS

Workers experienced various kinds of ailments. These included physical injuries, chest and respiratory tract associated symptoms, malaria, headaches, body pains and stomach discomfort. They reported seeking health care from multiple sources, and the main determinants of health seeking behaviour were severity of illness, perceived benefit of treatment, accessibility of service, quality of service, ease of communication with service provider and cost of health care.

CONCLUSION

Multiple sources of health care were used by the e-waste workers. As cost was a major barrier to accessing formal health care, most of the workers did not subscribe to health insurance. Since enrollment in health insurance is low amongst the workers, education campaigns on the need to register with the National Health Insurance Scheme would facilitate access to formal health care and could result in improved health outcomes among e-waste workers.

Exposure to polycyclic aromatic hydrocarbons could cause their oxidative DNA damage: a case study for college students in Guangzhou, China

Human exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs) in cigarette smoking might result in generation of reactive oxygen species (ROS) and induce formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG). This study was designed to examine whether levels of 8-OHdG are associated with levels of urinary metabolites of PAHs. Two groups (smokers and non-smokers) were recruited from college students in Guangzhou, China. Their urine samples were collected and analyzed for ten urinary mono-hydroxylated PAHs (OH-PAHs) and 8-OHdG by liquid chromatography equipped with tandem mass spectrometer (LC/MS/MS). Multiple linear regression analysis was performed to examine correlations between urinary levels of 8-OHdG and OH-PAHs. No significant difference was observed for creatinine-adjusted OH-PAHs between smokers and non-smokers. The levels of 8-OHdG between smokers and non-smokers were comparative. OH-PAH levels in this study were 2-50 times higher than those in populations from other countries and areas. The estimated daily intake (EDI; μg/day) of PAHs ranged from 0.02 to 371.4, which were far lower than the reference doses (RfDs) specified by U.S. Environmental Protection Agency (EPA). Though smoking was a main factor, which affected the PAH exposure, it was not a dominant factor in the exposure to PAHs of Guangzhou college students. The environmental exposure could not be ignored. The sum concentrations of OH-PAHs (∑OH-PAHs) had a dose-increase relationship with 8-OHdG both for smokers and non-smokers, especially for smokers. Though people in Guangzhou bore higher PAH hazards, the estimated environmental risk was still under safe ranges.

Working conditions and environmental exposures among electronic waste workers in Ghana

OBJECTIVE

To investigate and describe informal e-waste recycling and working conditions at Agbogbloshie, Accra, Ghana.

METHODS

We conducted in-depth interviews which were qualitatively analysed from a grounded theory perspective.

RESULTS

Workers obtained e-waste from the various residential areas in Accra, then dismantled and burned them in open air to recover copper, aluminum, steel, and other products for sale to customers on-site or at the nearby Agbogbloshie market. The processers worked under unhealthy conditions often surrounded by refuse and human excreta without any form of protective gear and were thus exposed to frequent burns, cuts, and inhalation of highly contaminated fumes. We observed no form of social security/support system for the workers, who formed informal associations to support one another in times of difficulty.

CONCLUSIONS

e-waste recycling working conditions were very challenging and presented serious hazards to worker health and wellbeing. Formalizing the e-waste processing activities requires developing a framework of sustainable financial and social security for the e-waste workers, including adoption of low-cost, socially acceptable, easy-to-operate, and cleaner technologies that would safeguard the health of the workers and the general public.

Personal exposure levels of PAHs in the general population in northern rural area of Jiangsu Province, China

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds that are produced by incomplete combustion of organic matters. Studies in humans have shown associations between PAHs exposure and development of cancers. Urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) are a class of PAH metabolites used as biomarkers for estimating human exposure to PAHs. We collected 332 urinary samples from a nonoccupational population in northern rural area of Jiangsu. Levels of 2-hydroxynathalene (2-OHN), 2-hydroxyfluorene (2-OHF) and 1-hydroxypyrene (1-OHP) were measured as biomarkers to assess body PAHs burdens. Three PAH metabolites were detected in more than 80% of urinary samples. After being adjusted with urinary creatinine concentration, the urinary concentrations were determined as 2-OHF > 1-OHP > 2-OHN in terms. The medians of 2-OHN, 2-OHF, 1-OHP for the general population were 1.74, 30.01, 25.24 μmoL/moL creatinine, respectively. The results demonstrated that nonoccupational populations in northern rural area of Jiangsu were exposed to extremely high PAHs. The urinary concentration (median and geometric mean) of 2-OHN,2-OHF,1-OHP in males (1.90, 0.37 ± 0.46; 34.90, 1.53 ± 0.41; 27.84, 1.52 ± 0.29 μmoL/moL creatinine, respectively) was slightly higher than in females (1.56, 0.32 ± 0.42; 29.60, 1.48 ± 0.40; 23.13, 1.49 ± 0.32 μmoL/moL creatinine, respectively). However, only 2-OHN was different significantly between males and females.

High levels of PAH-metabolites in urine of e-waste recycling workers from Agbogbloshie, Ghana

The informal recycling of electronic waste (e-waste) is an emerging source of environmental pollution in Africa. Among other toxins, polycyclic aromatic hydrocarbons (PAHs) are a major health concern for exposed individuals. In a cross-sectional study, the levels of PAH metabolites in the urine of individuals working on one of the largest e-waste recycling sites of Africa, and in controls from a suburb of Accra without direct exposure to e-waste recycling activities, were investigated. Socioeconomic data, basic health data and urine samples were collected from 72 exposed individuals and 40 controls. In the urine samples, concentrations of the hydroxylate PAH metabolites (OH-PAH) 1-hydroxyphenanthrene (1-OH-phenanthrene), the sum of 2- and 9-hydroxyphenanthrene (2-/9-OH-phenanthrene), 3-hydroxyphenanthrene (3-OH-phenanthrene), 4-hydroxyphenanthrene (4-OH-phenanthrene) and 1-hydroxypyrene (1-OH-pyrene), as well as cotinine and creatinine, were determined. In the exposed group, median urinary concentrations were 0.85 μg/g creatinine for 1-OH-phenanthrene, 0.54 μg/g creatinine for 2-/9-OH-phenanthrene, 0.99 μg/g creatinine for 3-OH-phenanthrene, 0.22 μg/g creatinine for 4-OH-phenanthrene, and 1.33 μg/g creatinine for 1-OH-pyrene, all being significantly higher compared to the control group (0.55, 0.37, 0.63, 0.11 and 0.54 μg/g creatinine, respectively). Using a multivariate linear regression analysis including sex, cotinine and tobacco smoking as covariates, exposure to e-waste recycling activities was the most important determinant for PAH exposure. On physical examination, pathological findings were rare, but about two thirds of exposed individuals complained about cough, and one quarter about chest pain. In conclusion, we observed significantly higher urinary PAH metabolite concentrations in individuals who were exposed to e-waste recycling compared to controls who were not exposed to e-waste recycling activities. The impact of e-waste recycling on exposure to environmental toxins and health of individuals living in the surroundings of e-waste recycling sites warrant further investigation.

Aflatoxin and PAH exposure biomarkers in a U.S. population with a high incidence of hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) is significantly elevated in a Hispanic community in Bexar County, Texas. Chronic exposure to dietary aflatoxins (AFs) is a major risk factor for HCC; increased risk has been linked to polycyclic aromatic hydrocarbon (PAH) co-exposure and hepatitis virus infection. The aims of this study were to assess AF and PAH exposures, investigate dietary factors that may contribute to increased AF exposure, and determine the prevalence of hepatitis virus infection in Bexar Co. Blood and urine samples were collected from 184 volunteers for biomarker analyses and hepatitis screening. Serum AFB(1)-lysine adduct, urinary AFM(1) and 1-hydroxypyrene (1-OHP) levels were measured using high-performance liquid chromatography. The average AFB(1)-lysine adduct level detected in 20.6% of serums was 3.84 ± 3.11 pg/mg albumin (range 1.01-16.57 pg/mg). AFM(1) was detected in 11.7% of urines, averaging 223.85 ± 250.56 pg/mg creatinine (range 1.89-935.49 pg/mg). AFM(1) detection was associated with increased consumption of corn tortillas (p=0.009), nuts (p=0.033) and rice (p=0.037). A significant difference was observed between mean 1-OHP values of non-smokers (0.07 ± 0.13) and smokers (0.80 ± 0.68) μmol/mol creatinine (p<0.01). A high hepatitis C virus positivity rate (7.1%) was observed. Findings suggest that the incidence and level of AF and PAH exposure were less than those observed in a high-risk population; however, participants consuming higher amounts of foods prone to AF contamination may be more vulnerable to exposure and interactions with other environmental/biological factors (i.e., HCV).

Is it time to advance the chemoprevention of environmental carcinogenesis with microdosing trials?

This perspective on Jubert et al. (beginning on page [1015] in this issue of the journal) discusses the use of microdosing with environmental carcinogens to accelerate the evaluation and optimization of chemopreventive interventions. The need for chemoprevention of environmental carcinogenesis is considered, as are the structure of microdosing, or phase 0, trials, technologies required to conduct microdose studies in this context, and ethical concerns. We also reflect on what microdosing studies have taught us to date.