Environmental Impacts on Children's Health in Southeast Asia: Genotoxic Compounds in Urban Air

Comet Test in Saliva Leukocytes of Pre-School Children Exposed to Air Pollution in North Italy: The Respira Study

Air pollution is a well-known problem for human health, especially for children living in highly polluted urban areas. This study aimed to assess the relationship between airborne pollutants concentration and biomarkers of DNA damage in the buccal mucosa cells of pre-school children. DNA damage was investigated with comet test in saliva leukocytes taken from sputum of 3- to 6-year-old children living in Brescia, Northern Italy, collected during two consecutive winter seasons (2012-2013). The daily levels of PM10, PM2.5, NO2, CO, SO2, benzene and O3 in urban air were collected for the whole period. A questionnaire filled in by the children's parents was used to evaluate indoor and outdoor exposure. DNA damage in saliva leukocytes was evaluated in 152 children and the means of tail intensity and visual score as DNA damage were 6.2 ± 4.3 and 182.1 ± 30.9, respectively. No demographic and indoor or outdoor exposure variable was associated with the two measures of DNA damage. No significant association between air pollution and DNA damage in children's buccal leukocytes was found. In this study, the comet assay does not appear to be a valuable biomarker to detect DNA damage in children exposed to high levels of air pollutants, such as PM10, PM2.5 and NO2.

Common issues related to children's environmental health in the Asia-Pacific region

This summary reports on the outcomes and common issues faced among the countries represented at the Asia-Pacific Regional Meeting on Children's Environmental Health, a meeting that was held at the Chulabhorn Research Institute in Bangkok, Thailand, and which focused on cross-cutting issues and commonalities among countries/regions, discussion of lessons learnt, exploring opportunities for policy-relevant research collaborations, and reviewing available educational tools to help translate research findings into tangible outputs. The common children's environmental health issues faced by countries in the Asia-Pacific region include indoor and outdoor air pollution; unregulated and inadequate waste management; chemical and infectious agents in water used for drinking and cooking; hazardous pesticide use; and climate change and extreme weather events. The meeting participants agreed there is a need for multisectoral involvement in each country to develop frameworks and guidelines, raising public awareness of risk, and managing exposures in order to tackle these common issues. Networking will allow countries to learn from each other and enhance their efforts to protect not only the health of children, but also that of the rest of the population at risk.

Children's Environmental Health in Thailand: Past, Present, and Future

Background:

There is increasing evidence of a link between environmental pollution and preventable diseases in developing countries, including Thailand. Economic development has generated several types of pollution that can affect population health. While these environmental health effects can be observed throughout life, pregnant women and children represent particularly vulnerable and sensitive groups.

Methods:

The published epidemiological literature investigating environmental chemical exposure in Thai children was reviewed, highlighting those that investigated associations between exposure and subsequent health outcomes.

Results:

The majority of the Thai epidemiological studies on environmental health in children were cross-sectional in design, with some demonstrating associations between exposure and outcome. The three main types of chemical exposure in Thai children were pesticides, heavy metals, and air pollution, which resulted from agricultural activities in countryside areas, industrial zones (both registered and unregistered establishments), mining, and traffic in inner cities. Major health outcomes included detrimental effects on cognitive function and cancer risk. Pesticide exposure was focused on, but not limited to, agricultural areas. The success of the Thai environmental policy to introduce lead–free petrol can be demonstrated by the decline of mean blood lead levels in children, particularly in urban areas. However, unregistered lead-related factories and smelters act as hidden sources. In addition, there is increasing concern, but little acknowledgement, about the effects of chronic arsenic exposure related to mining. Lastly, air pollution remains a problem in both dense city populations due to traffic and in rural areas due to contamination of indoor air and house dust with heavy metals, endotoxins and other allergens.

Conclusions:

The increasing number of published articles demonstrates an improved awareness of children’s environmental health in Thailand. Chemical hazards, including the improper use of pesticides, environmental contamination with heavy metals (lead and arsenic), and air pollution in inner cities and indoor air, continue to be growing issues.

The role of nutrition in influencing mechanisms involved in environmentally mediated diseases

Human exposure to environmental contaminants such as persistent chlorinated organics, heavy metals, pesticides, phthalates, flame retardants, electronic waste and airborne pollutants around the world, and especially in Southeast Asian regions, are significant and require urgent attention. Given this widespread contamination and abundance of such toxins as persistent organic pollutants (POPs) in the ecosystem, it is unlikely that remediation alone will be sufficient to address the health impacts associated with this exposure. Furthermore, we must assume that the impact on health of some of these contaminants results in populations with extraordinary vulnerabilities to disease risks. Further exacerbating risk; infectious diseases, poverty and malnutrition are common in the Southeast Asian regions of the world. Thus, exploring preventive measures of environmental exposure and disease risk through new paradigms of environmental toxicology, optimal and/or healthful nutrition and health is essential. For example, folic acid supplementation can lower blood arsenic levels, and plant-derived bioactive nutrients can lower cardiovascular and cancer risks linked to pollutant exposure. Data also indicate that diets enriched with bioactive food components such as polyphenols and omega-3 polyunsaturated fatty acids can prevent or decrease toxicant-induced inflammation. Thus, consuming healthy diets that exhibit high levels of antioxidant and anti-inflammatory properties, is a meaningful way to reduce the vulnerability to non-communicable diseases linked to environmental toxic insults. This nutritional paradigm in environmental toxicology requires further study in order to improve our understanding of the relationship between nutrition or other lifestyle modifications and toxicant-induced diseases. Understanding mechanistic relationships between nutritional modulation of environmental toxicants and susceptibility to disease development are important for both cumulative risk assessment and the design and implementation of future public health programs and behavioral interventions.

Polycyclic aromatic hydrocarbons (PAH) in Portuguese educational settings: a comparison between preschools and elementary schools

The aim of this study was to determine levels and risks due to inhalation exposure to polycyclic aromatic hydrocarbons (PAH) in different educational settings, namely for 3- to 5- year-old and 6- to 10-year-old children. Eighteen PAH (16 priority designated by US Environmental Protection Agency (USEPA) and dibenzo[a,l]pyrene and benzo[j]fluoranthene) were simultaneously collected in indoor and outdoor air at two Portuguese preschools (PS1-PS2) and five elementary schools (ES1-ES5) from March to May 2014. Indoor concentrations at PS and ES were significantly different, with total levels (∑PAHs) 0.721-15.9 ng/m³ at PS1-PS2 and 5.03-23.6 ng/m³ at ES1-ES5. The corresponding outdoor concentrations were, respectively, 1.22-32.7 ng/m³ and 2.6-31.5 ng/m³. Polycyclic aromatic hydrocarbons with 2-3 aromatic rings were predominantly emitted by indoor sources, while compounds with 4-6 aromatic rings were mainly generated by infiltration of ambient PAH pollution to indoors. Excess lifetime risks of lung cancer exceeded the World Health Organization (WHO) designated guideline of 10^-5 in both types of schools (15-42-fold at PS; 15-52-fold at ES). However, total (sum of indoor and outdoor exposure) incremental lifetime cancer risks (ILCR) were below the USEPA level of 10^-6 at all studied institutions and thus considered negligible. Finally, ILCR due to indoor exposure represented 60-75% and 70-85% of the total ILCR at PS and ES, respectively, thus indicating the need for development and implementation of indoor air quality guidelines in educations settings.

Assessment of exposure to polycyclic aromatic hydrocarbons in preschool children: Levels and impact of preschool indoor air on excretion of main urinary monohydroxyl metabolites

The present work aimed to assess exposure of preschool children to polycyclic aromatic hydrocarbons (PAHs) by environmental monitoring (eighteen compounds in air) and biomonitoring (six urinary biomarkers of exposure (OH-PAHs)). The impact of preschool indoor air on excretion of urinary monohydroxyl metabolites was also evaluated. Gaseous and particulate-bound PAHs were simultaneously collected indoors and outdoors in two Portuguese preschools. PAHs and OH-PAHs were quantified by high-performance liquid chromatography with fluorescence and photodiode array detection. Total air (gaseous+total suspended particles) levels of PAHs (ΣPAHs) were higher indoors than outdoors. Gaseous phase (composed by ≥98% of 2-3 rings compounds) and particulate-bound PAHs (90-99% of 5-6 rings) accounted for 93-95% and 5-7% of ΣPAHs in indoor air, respectively. Total (including probable/possible) carcinogenic PAHs represented 26-45% of ΣPAHs; naphthalene and dibenz[a,h]anthracene were the strongest contributors. A similar distribution profile was observed between airborne PAHs and urinary OH-PAHs. Urinary 1-hydroxynaphthalene+1-hydroxyacenaphthene represented more than 78% of ΣOH-PAHs, being followed by 2-hydroxyfluorene, 1-hydroxypyrene, and 1-hydroxyphenanthrene. 3-hydroxybenzo[a]pyrene (PAH biomarker of carcinogenicity) was not detected. Results suggest that children had preschool indoor air as their major exposure source of naphthalene and acenaphthene, while no conclusion was reached regarding fluorene, phenanthrene and pyrene.

Polycyclic aromatic hydrocarbons in primary school environments: Levels and potential risks

Although polycyclic aromatic hydrocarbons (PAHs) are priority air pollutants that strongly affect human health, information concerning the indoor exposures is still limited. This study characterized PAH levels in primary schools and evaluated risk for the respective students (aged 8-10years) in comparison with school personnel. During January-April 2014, eighteen particulate-bound (PM_2.5) PAHs (16 USEPA priority compounds, dibenzo[a,l]pyrene, benzo[j]fluoranthene) were collected (indoors and outdoors) at ten primary urban schools in Portugal. Total mean concentrations (Σ_PAHs) ranged 2.8-54ngm^-3 in indoor air, whereas corresponding outdoor levels were 7.1-48ngm^-3. Indoor/outdoor ratios of lighter congeners (2-3 aromatic rings) demonstrated a contribution from indoor origin while heavier PAHs (4-6 aromatic rings) originated mostly from infiltration of ambient air indoors; traffic (both from diesel and gasoline fuelled vehicles) was the predominant source of indoor PAHs. Total cancer risk of 8-10years old children exceeded (up to 22 times) USEPA recommended guideline of 10^-6, and 7-87 times WHO health-based threshold of 10^-5. Risk due to indoor exposure in schools was 2-10 times higher than outdoors, mainly because of the higher amount of time that students spent indoors.

Assessment of polycyclic aromatic hydrocarbons in indoor and outdoor air of preschool environments (3-5 years old children)

This work characterizes levels of polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air of preschool environments, and assesses the respective risks for 3-5-years old children. Eighteen gaseous and particulate (PM1 and PM2.5) PAHs were collected indoors and outdoors during 63 days at preschools in Portugal. Gaseous PAHs accounted for 94-98% of total concentration (ΣPAHs). PAHs with 5-6 rings were predominantly found in PM1 (54-74% particulate ΣPAHs). Lighter PAHs originated mainly from indoor sources whereas congeners with 4-6 rings resulted mostly from outdoor emissions penetration (motor vehicle, fuel burning). Total cancer risks of children were negligible according to USEPA, but exceeded (8-13 times) WHO health-based guideline. Carcinogenic risks due to indoor exposure were higher than for outdoors (4-18 times).

Polycyclic aromatic hydrocarbons: levels and phase distributions in preschool microenvironment

This work aims to characterize levels and phase distribution of polycyclic aromatic hydrocarbons (PAHs) in indoor air of preschool environment and to assess the impact of outdoor PAH emissions to indoor environment. Gaseous and particulate (PM1 and PM(2.5)) PAHs (16 USEPA priority pollutants, plus dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were concurrently sampled indoors and outdoors in one urban preschool located in north of Portugal for 35 days. The total concentration of 18 PAHs (ΣPAHs) in indoor air ranged from 19.5 to 82.0 ng/m(3) ; gaseous compounds (range of 14.1-66.1 ng/m(3)) accounted for 85% ΣPAHs. Particulate PAHs (range 0.7-15.9 ng/m(3)) were predominantly associated with PM1 (76% particulate ΣPAHs) with 5-ring PAHs being the most abundant. Mean indoor/outdoor ratios (I/O) of individual PAHs indicated that outdoor emissions significantly contributed to PAH indoors; emissions from motor vehicles and fuel burning were the major sources.

Exposure to polycyclic aromatic hydrocarbons and assessment of potential risks in preschool children

As children represent one of the most vulnerable groups in society, more information concerning their exposure to health hazardous air pollutants in school environments is necessary. Polycyclic aromatic hydrocarbons (PAHs) have been identified as priority air pollutants due to their mutagenic and carcinogenic properties that strongly affect human health. Thus, this work aims to characterize levels of 18 selected PAHs in preschool environment, and to estimate exposure and assess the respective risks for 3-5-year-old children (in comparison with adults). Gaseous PAHs (mean of 44.5 ± 12.3 ng m(-3)) accounted for 87% of the total concentration (ΣPAHs) with 3-ringed compounds being the most abundant (66% of gaseous ΣPAHs). PAHs with 5 rings were the most abundant ones in the particulate phase (PM; mean of 6.89 ± 2.85 ng m(-3)) being predominantly found in PM1 (78% particulate ΣPAHs). Overall child exposures to PAHs were not significantly different between older children (4-5 years old) and younger ones (3 years old). Total carcinogenic risks due to particulate-bound PAHs indoors were higher than outdoor ones. The estimated cancer risks of both preschool children and the staff were lower than the United States Environmental Protection Agency (USEPA) threshold of 10(-6) but slightly higher than WHO-based guideline.

Applications of the comet assay in particle toxicology: air pollution and engineered nanomaterials exposure

Exposure to ambient air particles is associated with elevated levels of DNA strand breaks (SBs) and endonuclease III, formamidopyrimidine DNA glycosylase (FPG) and oxoguanine DNA glycosylase-sensitive sites in cell cultures, animals and humans. In both animals and cell cultures, increases in SB and in oxidatively damaged DNA are seen after exposure to a range of engineered nanomaterials (ENMs), including carbon black, carbon nanotubes, fullerene C60, ZnO, silver and gold. Exposure to TiO2 has generated mixed data with regard to SB and oxidatively damaged DNA in cell cultures. Nanosilica does not seem to be associated with generation of FPG-sensitive sites in cell cultures, while large differences in SB generation between studies have been noted. Single-dose airway exposure to nanosized carbon black and multi-walled carbon nanotubes in animal models seems to be associated with elevated DNA damage levels in lung tissue in comparison to similar exposure to TiO2 and fullerene C60. Oral exposure has been associated with augmented DNA damage levels in cells of internal organs, although the doses have been typically very high. Intraveneous and intraperitoneal injection of ENMs have shown contradictory results dependent on the type of ENM and dose in each set of experiments. In conclusion, the exposure to both combustion-derived particles and ENMs is associated with increased levels of DNA damage in the comet assay. Particle size, composition and crystal structure of ENM are considered important determinants of toxicity, whereas their combined contributions to genotoxicity in the comet assay are yet to be thoroughly investigated.

Genotoxic and hematological effects in children exposed to a chemical mixture in a petrochemical area in Mexico

Children living in Coatzacoalcos, Veracruz, and in nearby surrounding areas are exposed to a mixture of pollutants from different sources. Previous studies in the area have reported genotoxic and haematotoxic compounds, such as lead (Pb), benzene, toluene, and polycyclic aromatic hydrocarbons (PAHs), in environmental and biological samples. The final toxic effects of these compounds are unknown because the toxic behaviour of each compound is modified when in a complex mixture. This is the first study on the exposure and effect of chemical mixtures on children who live near a petrochemical area. The aim of this study was to evaluate genotoxicity and haematological effects in children environmentally exposed to such mixtures and to determine whether the final effect was modified by the composition of the mixture composition. Biomarkers of exposure to Pb, benzene, toluene, and PAHs were quantified in urine and blood samples of 102 children. DNA damage was evaluated using comet assay, and haematological parameters were determined. Our results show that Pb and toluene did not surpass the exposure guidelines; the exposure was similar in all three localities (Allenede, Mundo Nuevo, and López Mateos). In contrast, exposure to PAHs was observed at three levels of exposure: low, medium, and high. The most severe effects of these mixtures were strictly related to coexposure to high levels of PAHs.

Urinary levels of 1-hydroxypyrene in children residing near a coal-fired power plant

BACKGROUND

The effects of emissions from coal-fired power plants on children's exposure to polycyclic aromatic hydrocarbons (PAHs) are not well understood.

OBJECTIVES

This study aimed to evaluate the sources and the urinary levels of 1-hydroxypyrene, a biomarker of exposure to PAHs, among children living in proximity to a coal-fired power plant.

METHODS

Study areas consisted of two high exposure and two low exposure communities, at different distances and directions from a large coal-fired power plant in central Taiwan. Study subjects included 369 children aged 1-13 years and randomly selected from each community. Each child's urinary 1-hydroxypyrene concentration was measured by a high-performance liquid chromatography-fluorescence detector method. Samples of ambient air were analyzed for PAHs using a gas chromatography-mass spectrometry method. Information on important factors was collected by an interview using a structured questionnaire. Multiple regression analysis was used to assess factors significantly associated with urinary 1-hydroxypyrene levels.

RESULTS

Levels of PAHs in ambient air in the high exposure communities were higher than those in the low exposure communities. Children living in high exposure communities had higher mean urinary 1-hydroxypyrene concentrations than those in low exposure communities (0.186 and 0.194 vs. 0.113 and 0.122 μmol/mol-creatinine, respectively). The difference in urinary 1-hydroxypyrene levels between the high exposure communities and one low exposure community remained significant after adjusting for age, gender, environmental tobacco smoke, dietary exposure, and traffic.

CONCLUSIONS

Children living in communities downwind of and in proximity to the coal-fired power plant had significantly increased urinary 1-hydroxypyrene levels.

Assessment of potential cancer risk in children exposed to urban air pollution in Bangkok, Thailand

Urban air pollution resulting from traffic is a major problem in many cities in Asia, including Bangkok, Thailand. This pollution originates mainly from incomplete fossil fuel combustion, e.g. transportation, and the composition of which is very complex. Some of the compounds are carcinogenic in experimental animals and in man. Polycyclic aromatic hydrocarbons (PAHs) and benzene are among the major carcinogenic compounds found in urban air pollution from motor vehicle emissions. In major cities in Asia, the levels of PAHs and benzene are relatively high compared with those in Europe or in the United States and thus people are exposed to higher levels. Biomarkers of exposure and early biological effects have been used to study the potential health effects of exposure to PAHs and benzene in air pollution in school children attending schools in inner-city Bangkok compared to those attending schools in rural areas. Bangkok school children are exposed to total PAHs at levels 3.5-fold higher than those in the rural area. Urinary 1-hydroxypyrene, a metabolite of PAH, was also significantly higher, while PAH-DNA adducts in lymphocytes were five-fold higher in Bangkok school children than rural school children. Benzene exposure in Bangkok school children was approximately two-fold higher than in rural school children. This is in agreement with the levels of biomarkers of internal benzene dose, i.e. blood benzene and urinary t,t-muconic acid. The potential health risks from exposure to genotoxic substances were assessed through DNA-damage levels and DNA repair capacity. DNA strand breaks were significantly higher, whereas DNA repair capacity was significantly reduced in Bangkok children. Genetic polymorphisms have been detected in glutathione-S-transferases (GSTs) and cytochrome P450 (CYP450) enzymes involved in the metabolism of benzene and PAHs, but these polymorphisms had no significant effects on the biomarkers of PAH exposure. Our results indicate that children living in a mega city such as Bangkok may have an increased health risk of the development of certain diseases due to exposure to genotoxic substances in air pollution compared to children living in suburban/rural areas.