Approaches to environmental exposure assessment in children

Recent and projected changes in global climate may increase nicotine absorption and the risk of green tobacco sickness

BACKGROUND

Dermal transfer of nicotine during tobacco harvest can cause green tobacco sickness (GTS), characterized by nausea, vomiting, headache and dizziness. Rainfall and high temperatures are etiological factors known to increase the prevalence of GTS. We analyzed recent and projected trends in these factors for major tobacco-growing regions to assess potential exacerbation in GTS occurrence.

METHODS

We analyzed climate parameters, including recent trends (since the 1970s) in temperature and precipitation metrics during the tobacco harvest period for Southern Brazil; Yunnan Province, China; Andhra State, India; and North Carolina, USA. We applied Shared Socio-economic Pathways (SSPs) based scenarios for Tier 1 Scenario Model Intercomparison Project (ScenarioMIP) within the Coupled Model Intercomparison Project phase 6 (CMIP6), (SSPs of 1-2.6, 3-7.0 and 5-8.5 from 2020 to 2100). Established protocol for nicotine dermal patches and temperature were used as a proxy to estimate potential nicotine absorption.

RESULTS

For three locations, cumulative maximum temperatures during harvest and temperature extremes rose significantly since the 1970s as did cumulative rainfall during harvest. Projected maximum temperatures at SSP 3-7.0 and 5-8.5 projections through 2100 did increase for all locations. Estimates of nicotine skin absorption with rising temperature show significant increases for both recent changes in three locations, and for all locations for SSP projections of 3-7.0 and 5-8.5 from 2020 to 2100.

CONCLUSIONS

This study across multiple continents, highlights a potential link between recent and projected anthropogenic change and potential increases in GTS risk. Under SSP 5-8.5, nicotine absorption could increase by ~50% by the end of the century, which may have widespread impacts on the incidence of GTS, especially among younger tobacco workers.

Recent and Projected Changes in Global Climate May Increase Nicotine Absorption and the Risk of Green Tobacco Sickness

Background

Dermal transfer of nicotine during tobacco harvest can increase green tobacco sickness (GTS), characterized by nausea, vomiting, headache and dizziness. Rainfall and temperature are established etiological factors known to increase prevalence of GTS. We aimed to analyze recent and projected trends in these factors for major tobacco growing regions to assess potential exacerbation in GTS occurrence.

Methods

We analyzed climate parameters, including trends in temperature and precipitation metrics during the tobacco harvest period for Southern Brazil; Yunnan Province, China; Andhra State, India; and North Carolina, USA (~50-year period). We applied Shared Socio-economic Pathways (SSPs) based scenarios for CMIP6, (SSPs of 1-2.6, 3-7.0 and 5-8.5 from 2020 to 2100). Established protocol for nicotine dermal patches and temperature was used as a proxy to estimate potential nicotine absorption with rising temperature.

Results

For three locations, cumulative maximum temperatures during harvest season and temperature extremes increased significantly since the 1970s. For all locations, cumulative rainfall during the harvest season also rose. Projected maximum temperatures for the harvest season increased at SSP 3-7.0 and 5-8.5 projections through 2100 for all locations. Estimates of nicotine skin absorption with rising temperature indicate significant increases for both recent changes (since the 1970s) in three of the four locations, and for all locations for the SSP projections of 3-7.0 and 5-8.5 from 2020 to 2100.

Conclusions

This study across multiple continents, highlights a potential link between recent and projected anthropogenic change and potential increases in GTS risk. Under SSP 5-8.5, nicotine absorption could increase by ~50% by the end of the century, which may have widespread impacts on the incidence of GTS, especially among younger tobacco workers.

Probabilistic human health risk assessment associated with fluoride and arsenic co-occurrence in drinking water from the metropolitan area of San Luis Potosí, Mexico

A major public health concern in Mexico is the natural contamination of groundwater with fluoride and arsenic. Therefore, this work aimed to evaluate the magnitude of human health risk after determining fluoride and arsenic concentrations in groundwater samples (n = 50) from the Metropolitan area of the city of San Luis Potosi, Mexico. Fluoride levels in water were determined via a potentiometric method using an ion-selective electrode. Arsenic concentrations in water samples were determined with an Atomic Absorption technique. Subsequently, a probabilistic health risk assessment was developed (Monte Carlo Analysis). Fluoride levels in water ranged from 0.20 to 3.50 mg/L. For arsenic, the mean level found in the assessed water samples was 15.5 ± 5.50 μg/L (range: 2.50-30.0 μg/L). In addition, when the probabilistic health risk assessment was completed, a mean HI (cumulative hazardous index) of higher than 1 was detected, indicating a high NCR (non-carcinogenic risk) for children and adults. According to the results found in this study, exposure protection campaigns are imperative in the Metropolitan area of the city of San Luis Potosí, Mexico, to successfully diminish exposure to arsenic and fluoride and, as a consequence, decrease the NCR in the population living in that region of Mexico.

The levels of polycyclic aromatic hydrocarbons (PAHs) in human milk and exposure risk to breastfed infants in petrochemical industrialized Lanzhou Valley, Northwest China

We investigated in this paper the presence of PAHs in human milk from lactating women residing in Lanzhou, a petrochemical industrialized valley city in Northwest China. The PAH concentration levels in human milk samples from 98 healthy women were determined by gas chromatography/mass spectrometry (GC/MS). The associations between the lifestyle factors and the PAHs levels of human milk were analyzed. Moreover, we applied principal component analysis (PCA) method to gain a better insight into the similarities or dissimilarities of the human milk PAH loads and different pathways of source exposure. In addition, the exposure risks of breastfed infants due to PAH ingestion via breast milk were assessed and the relative breast-feeding risk to the total intake dose of infants was addressed. The results showed that the average fat-normalized human milk ∑₁₅PAHs concentrations for the lactating women residing in four districts of Lanzhou, namely, Xigu, Anning, Qilihe, and Chengguan were 320.40, 270.36, 374.04, and 259.84 ng/g of fat, respectively. The ∑₁₅PAHs of human milk from the lactating women of Qilihe District exhibited the highest concentration level, while the concentration level for women from Xigu District is the second highest for the observed human milk ∑₁₅PAHs. And the corresponding BaPeq concentrations for women in Xigu, Anning, Qilihe, and Chengguan districts were 58.29, 47.95, 65.13, and 45.60 ng/g of fat, respectively. A significant correlation was only found between human milk and living district environment (p < 0.05). Although the Spearman correlation analysis showed that there were no significant correlation existing between other lifestyle and human milk PAHs, we confirmed that consuming barbecue food could elevate PAHs levels in human milk: the barbecue intake frequency caused 10% fluctuation of ∑₁₅PAHs concentration between high frequency and low frequency group in our study. Furthermore, the exposure to second-hand smoke can also increase the ∑₁₅PAHs levels in human milk by 4 to 11% here. Ingestion doses of PAHs by infants (19.37-77.75 ng kg^-1 day^-1) were much higher than the inhalation doses (2.83-16.48 ng kg^-1 day^-1), which indicated that the ingestion is the main exposure risk pathway for infants. Since there are limited guidelines and standards for PAHs ingestion dose in human milk by infant, we compared the ingestion dose of BaP with the upper bound estimates of BaP dietary exposure of 108 ng kg^-1 day^-1 for toddlers of ages between 1.5 and 2.5 years of age in the UK reported by Committee on Toxicity of Chemicals in Food (COT) and the data we obtained were lower than this upper bound. However, the estimated margin of exposure (MOE) values of BaP-MOE, PAH2-MOE, PAH4-MOE, and PAH8-MOE were smaller than 10,000 which indicated that there are potential hazard for breastfed infants consuming these human milk samples.

Polybrominated diphenyl ethers (PBDEs) levels in blood samples from children living in the metropolitan area of Guadalajara, Jalisco, Mexico

The aim of this study was to perform a polybrominated diphenyl ethers (PBDEs) exposure assessment using blood samples collected from children living in the metropolitan area of Guadalajara, Jalisco, Mexico (GDL). Five congeners of PBDEs were analyzed using a gas chromatography/mass spectrometry technique. The blood concentrations of total PBDEs ranged from 5.50 to 169 ng/g lipid (42.0 ± 18.0 ng/g lipid; mean ± standard deviation). Regarding BDE congeners, the main congener (highest blood levels) was BDE99 (14.5 ± 5.50 ng/g lipid), followed by BDE100 (9.80 ± 3.40 ng/g lipid) and BDE154 (9.80 ± 5.90 ng/g lipid), and finally BDE153 (5.80 ± 2.30 ng/g lipid) and BDE47 (2.20 ± 1.20 ng/g lipid). In conclusion, blood PBDEs concentrations of concern were detected in this study, as blood levels were similar to the ones found in North America (the highest worldwide).

Arsenic urinary concentrations in children living in a naturally arsenic contaminated area

A cross sectional study using environmental and biological samples was undertaken to assess the association between arsenic (As) soil concentrations and urinary As levels of children living in an area where the soil is naturally As rich, during summer and winter. Twenty-nine children aged between 2 and 7 years from 21 dwellings in the summer study, and 23 of the 29 previous children from 17 dwellings in the winter study, were recruited. Housing characteristics, living conditions and individual characteristics were collected by questionnaire, and urine samples were collected for iAs+MMA+DMA measurement. Soil total As content and bioaccessibility were measured. Urinary As concentrations revealed that the children were not overexposed. Low bioaccessibility combined with moderately high levels in soil could explain this result. The concentration of arsenic in soil and soil-related factors appeared to contribute to the children's impregnation in summer but not in winter, which could be related to the children's behavior. This study highlights the need for additional studies of children to better understand their behavior, and obtain reference values in this particular population.

Environmental exposure assessment of pesticides in farmworker homes

Farmworkers and their families are exposed to pesticides both at work and in their homes. Environmental exposure assessment provides a means to evaluate pesticides in the environment and human contact with these chemicals through identification of sources and routes of exposure. To date, a variety of methods have been used to assess pesticide exposure among farmworker families, mostly focusing on dust and handwipe samples. While many of the methods are similar, differences in the collection, chemical analysis, and statistical analysis, can limit the comparability of results from farmworker studies. This mini-monograph discusses the strategies used to assess pesticide exposures, presents limitations in the available data for farmworkers, and suggests research needs for future studies of pesticide exposure among farmworker families.

Air pollution exposure assessment for epidemiologic studies of pregnant women and children: lessons learned from the Centers for Children's Environmental Health and Disease Prevention Research

The National Children's Study is considering a wide spectrum of airborne pollutants that are hypothesized to potentially influence pregnancy outcomes, neurodevelopment, asthma, atopy, immune development, obesity, and pubertal development. In this article we summarize six applicable exposure assessment lessons learned from the Centers for Children's Environmental Health and Disease Prevention Research that may enhance the National Children's Study: a) Selecting individual study subjects with a wide range of pollution exposure profiles maximizes spatial-scale exposure contrasts for key pollutants of study interest. b) In studies with large sample sizes, long duration, and diverse outcomes and exposures, exposure assessment efforts should rely on modeling to provide estimates for the entire cohort, supported by subject-derived questionnaire data. c) Assessment of some exposures of interest requires individual measurements of exposures using snapshots of personal and microenvironmental exposures over short periods and/or in selected microenvironments. d) Understanding issues of spatial-temporal correlations of air pollutants, the surrogacy of specific pollutants for components of the complex mixture, and the exposure misclassification inherent in exposure estimates is critical in analysis and interpretation. e) "Usual" temporal, spatial, and physical patterns of activity can be used as modifiers of the exposure/outcome relationships. f) Biomarkers of exposure are useful for evaluation of specific exposures that have multiple routes of exposure. If these lessons are applied, the National Children's Study offers a unique opportunity to assess the adverse effects of air pollution on interrelated health outcomes during the critical early life period.

Environmental health of children

Pediatric primary health care providers are responsible for providing comprehensive care to children. This includes assessing for and identifying the effect of environmental hazards on children's health and managing conditions that may result from exposure to environmental toxins. This article begins by reviewing the unique developmental, biologic, and behavioral characteristics of children and age-specific issues that make them particularly vulnerable to toxins. It then provides the reader with general assessment and management strategies related to environmental toxins, including an assessment tool that can be used in a pediatric primary care office. The qualities of selected toxins that have been implicated in childhood illnesses are discussed. Routes of exposure, signs and symptoms of toxicity, and assessment and management approaches are presented specifically for lead, mercury, environmental tobacco smoke, particulate matter, asbestos, radon, molds, and pesticides. Because prevention is the best intervention in environmental health, the article emphasizes ways pediatric providers can work with caregivers to prevent or minimize exposure.

The sentinel role of poisons centers in the protection of children's environmental health

Growing concern exists about the threats posed by environmental pollutants and physical agents on children's health. A number offactors, including globalization, increased industrialization, and trade of chemicals and poverty have an impact on the quality of the environment and on children's health. Acute toxic exposures lead to poisoning, and chronic low-level exposures may cause functional and organ damage during periods of special vulnerability. The need to protect children's environmental health is urgent, in view of the magnitude of the problem and the fact that "children are not little adults." The effects suffered during special developmental periods-"windows of vulnerability"-can be permanent and irreversible. The main global environmental problems affecting children's health are lack of access to safe drinking water and sanitation and exposure to indoor air pollution. Furthermore, environmentally related accidents, injuries, and poisonings have a major impact on children and adolescent's morbidity and mortality. A number of examples that illustrate the complexity of assessing and dealing with children's environmental health issues are presented. A Task Force on the Protection of Children's Environmental Health that aims to prevent disease and disability in children associated with chemical and physical threats was set up in 1999 by the World Health Organization. The priorities for action include the consideration of accidents, injuries, and poisonings (accidental, intentional, and occupational), and children in the workplace (e.g., scavenging children, children in cottage industries). Poisons Centers and related toxicology centers are in a strategic position to play a "sentinel" role in the protection of children's environmental health. They record acute and chronic toxic exposures in children in a harmonized manner, using controlled vocabularies and definitions. This will allow collecting a large, highly valuable database on the main toxicological problems affecting children, including those of environmental origin. The analysis of observations entered in such a database will help assess the burden of disease and collect the evidence for planning prevention and promoting regulatory measures. Centers are called to play a proactive role in raising awareness about children's environmental health and contribute to research, information dissemination, training, and other activities required for the protection of children's health and development.

Children's exposure assessment: a review of factors influencing Children's exposure, and the data available to characterize and assess that exposure

We review the factors influencing children's exposure to environmental contaminants and the data available to characterize and assess that exposure. Children's activity pattern data requirements are demonstrated in the context of the algorithms used to estimate exposure by inhalation, dermal contact, and ingestion. Currently, data on children's exposures and activities are insufficient to adequately assess multimedia exposures to environmental contaminants. As a result, regulators use a series of default assumptions and exposure factors when conducting exposure assessments. Data to reduce uncertainty in the assumptions and exposure estimates are needed to ensure chemicals are regulated appropriately to protect children's health. To improve the database, advancement in the following general areas of research is required: identification of appropriate age/developmental benchmarks for categorizing children in exposure assessment; development and improvement of methods for monitoring children's exposures and activities; collection of activity pattern data for children (especially young children) required to assess exposure by all routes; collection of data on concentrations of environmental contaminants, biomarkers, and transfer coefficients that can be used as inputs to aggregate exposure models.