Jacqueline Moya

Frequency of mouthing behavior in young children

Young children may be more likely than adults to be exposed to pesticides following a residential application as a result of hand- and object-to-mouth contacts in contaminated areas. However, relatively few studies have specifically evaluated mouthing behavior in children less than 5 years of age. Previously unpublished data collected by the Fred Hutchinson Cancer Research Center (FHCRC) were analyzed to assess the mouthing behavior of 72 children (37 males/35 females). Total mouthing behavior data included the daily frequency of both mouth and tongue contacts with hands, other body parts, surfaces, natural objects, and toys. Eating events were excluded. Children ranged in age from 11 to 60 months. Observations for more than 1 day were available for 78% of the children. The total data set was disaggregated by gender into five age groups (10–20, 20–30, 30–40, 40–50, 50–60 months). Statistical analyses of the data were then undertaken to determine if significant differences existed among the age/gender subgroups in the sample. A mixed effects linear model was used to test the associations among age, gender, and mouthing frequencies. Subjects were treated as random and independent, and intrasubject variability was accounted for with an autocorrelation function. Results indicated that there was no association between mouthing frequency and gender. However, a clear relationship was observed between mouthing frequency and age. Using a tree analysis, two distinct groups could be identified: children ≤24 and children >24 months of age. Children ≤24 months exhibited the highest frequency of mouthing behavior with 81±7 events/h (mean±SE) (n=28 subjects, 69 observations). Children >24 months exhibited the lowest frequency of mouthing behavior with 42±4 events/h (n=44 subjects, 117 observations). These results suggest that children are less likely to place objects into their mouths as they age. These changes in mouthing behavior as a child ages should be accounted for when assessing aggregate exposure to pesticides in the residential environment.

Focusing on Children's Inhalation Dosimetry and Health Effects for Risk Assessment: An Introduction

Substantial effort has been invested in improving childrens health risk assessment in recent years. However, the body of scientific evidence in support of childrens health assessment is constantly advancing, indicating the need for continual updating of risk assessment methods. Childrens inhalation dosimetry and child-specific adverse health effects are of particular concern for risk assessment. When focusing on this topic within childrens health, key issues for consideration include (1) epidemiological evidence of adverse effects following childrens exposure to air pollution, (2) ontogeny of the lungs and effects on dosimetry, (3) estimation and variability of childrens inhalation rates, and (4) current risk assessment methodologies for addressing children. In this article, existing and emerging information relating to these key issues are introduced and discussed in an effort to better understand childrens inhalation dosimetry and adverse health effects for risk assessment. While much useful evidence is currently available, additional research and methods are warranted for improved childrens health risk assessment.

Overview of Fish Consumption Rates in the United States

ABSTRACT Contaminants that accumulate in fish may pose health risks and have raised concerns among consumers. Contaminated finfish and shellfish are possible routes of human exposure to toxic chemicals. Fish advisories are established to protect local populations from the consumption of contaminated commercial and non-commercially caught fish. Children, women of childbearing age, and subsistence fishermen or other highly exposed individuals who for socioeconomic or cultural reasons consume more fish than the general population are among the populations of concern from the ingestion of contaminated fish. Estimating exposure to a toxic chemical among fish-consuming populations requires knowledge about intake rates of fish and shellfish. Data on fish consumption rates come from various sources, including national, state, and local government studies. Although these data have their limitations, they serve as a source for deriving fish consumption rates that may be used by exposure assessors. Data on specific populations of concern are critical. Studies presented here show that ethnicity, age, and geographical region play an important role in fishing behavior and consumption. Results from studies on Native American populations show that this ethnic group eats fish at a higher rate than recreational anglers. This article summarizes data on fish consumption for various populations and provides a framework for evaluating data from these studies for exposure assessment applications.

A meta-analysis of children's object-to-mouth frequency data for estimating non-dietary ingestion exposure.

To improve estimates of non-dietary ingestion in probabilistic exposure modeling, a meta-analysis of childrens object-to-mouth frequency was conducted using data from seven available studies representing 438 participants and ∼1500 h of behavior observation. The analysis represents the first comprehensive effort to fit object-to-mouth frequency variability and uncertainty distributions by indoor/outdoor location and by age groups recommended by the US Environmental Protection Agency for assessing childhood exposures. Weibull distributions best fit the observed data from studies with no statistical differences, and are presented by study, age group, and location. As age increases, both indoor and outdoor object-to-mouth frequencies decrease. Object-to-mouth frequency is significantly greater indoors (2–32 contacts/h) than outdoors (average 1–9 contacts/h). This paper compares results to a similar hand-to-mouth frequency meta-analysis. Children who tend to mouth hands indoors also tend to mouth hands outdoors; children who tend to mouth objects indoors tend to mouth objects outdoors. However, children who tend to mouth objects do not necessarily have a tendency to mouth hands. Unlike for hand-to-mouth frequency, a statistical difference was found among the various studies for object-to-mouth frequency. This could be due to different definitions for object mouthing across the studies considered. The analysis highlights the need for additional object-to-mouth data (indoors and especially outdoors) for various age groups using standardized collection and analysis.

A review of physiological and behavioral changes during pregnancy and lactation: Potential exposure factors and data gaps

Exposures to environmental contaminants can pose risks to pregnant women’s health, their developing fetuses, children, and adults later in their lives. Assessing risks to this potentially susceptible population requires a sound understanding of the physiological and behavioral changes that occur during pregnancy and lactation. Many physiological and anatomical changes occur in a woman’s organ systems during the course of pregnancy and lactation. For example, blood volume and cardiac output increase during pregnancy, and other metabolic functions are altered to provide for the demands of the fetus. During lactation, nutritional demands are greater than during pregnancy. There are also changes in behavior during both pregnancy and lactation. For example, water consumption during pregnancy and lactation increases. These behavioral and physiological changes can lead to different environmental exposures than these women might otherwise experience in the absence of pregnancy or lactation. This paper provides a summary of information from the published literature related to behavioral and physiological changes in pregnant and lactating women that may affect their exposure or susceptibility to environmental contaminants, provides potentially useful exposure factor data for this population of women, and highlights data gaps.

A lifestage approach to assessing children's exposure

Understanding and characterizing risks to children has been the focus of considerable research efforts at the U.S. Environmental Protection Agency (EPA). Potential health risks resulting from environmental exposures before conception and during pre- and postnatal development are often difficult to recognize and assess because of a potential time lag between the relevant periods of exposure during development and associated outcomes that may be expressed at later lifestages. Recognizing this challenge, a lifestage approach for assessing exposure and risk is presented in the recent EPA report titled A Framework for Assessing Health Risks of Environmental Exposures to Children (U.S. EPA, 2006). This EPA report emphasizes the need to account for the potential exposures to environmental agents during all stages of development, and consideration of the relevant adverse health outcomes that may occur as a result of such exposures. It identifies lifestage-specific issues associated with exposure characterization for regulatory risk assessment, summarizes the lifestage-specific approach to exposure characterization presented in the Framework, and discusses emerging research needs for exposure characterization in the larger public-health context. This lifestage approach for characterizing childrens exposures to environmental contaminants ensures a more complete evaluation of the potential for vulnerability and exposure of sensitive populations throughout the life cycle.

A review of soil and dust ingestion studies for children

Soil and dust ingestion by children may be important pathways of exposure to environmental contaminants. Contaminated soil and dust may end up on children’s hands and objects, because they play close to the ground. These contaminants can be ingested by children, because they have a tendency to place objects, including their fingers, in their mouths. Assessing exposure through this pathway requires information about the amount of soil and dust ingested by children. Estimates of soil and dust ingestion and information on the prevalence of the behavior have been published in the literature, but research in this area is generally limited. Three methodologies have been used to quantify soil and dust ingestion rates. In this paper, these are referred to as the tracer element method, the biokinetic model comparison method, and the activity pattern method. This paper discusses the information available on the prevalence of soil and dust ingestion behavior, summarizes the three methodologies for quantifying soil and dust ingestion, and discusses their limitations. Soil ingestion data derived from studies that use these methodologies are also summarized. Although they are based on different estimation approaches, the central tendency estimates of soil and dust ingestion derived from the three methodologies are generally comparable.

Estimated long-term fish and shellfish intake—national health and nutrition examination survey

Usual intake estimates describe long-term average intake of food and nutrients and food contaminants. The frequencies of fish and shellfish intake over a 30-day period from National Health and Examination Survey (NHANES 1999–2006) were combined with 24-h dietary recall data from NHANES 2003–2004 using a Monte Carlo procedure to estimate the usual intake of fish and shellfish in this study. Usual intakes were estimated for the US population including children 1 to <11 years, males/females 11 to <16 years, 16 to <21 years, and adults 21+ years. Estimated mean fish intake (consumers only) was highest among children 1 to <2 years and 2 to <3 years, at 0.37 g/kg-day for both age groups, and lowest for females 11 to <16 years, at 0.13 g/kg-day. In all age groups, daily intake estimates were highest for breaded fish, salmon, and mackerel. Among children and teenage consumers, tuna, salmon, and breaded fish were the most frequently consumed fish; shrimp, scallops, and crabs were the most frequently consumed shellfish. The intake estimates from this study better reflect long-term average intake rates and are preferred to assess long-term intake of nutrients and possible exposure to environmental contaminants from fish and shellfish sources than 2-day average estimates.

Estimates of fish consumption rates for consumers of bought and self-caught fish in Connecticut, Florida, Minnesota, and North Dakota.

Fish consumption rates derived from national surveys may not accurately reflect consumption rates in a particular population such as recreational anglers. Many state and local health agencies in the U.S. have conducted area-specific surveys to study fish consumption patterns in local populations, assess exposure to environmental contaminants, or evaluate compliance with fish advisories. The U.S. Environmental Protection Agency (EPA) has analyzed the raw data from fish consumption surveys in Florida, Connecticut, Minnesota, and North Dakota for the purpose of deriving distributions of fish consumption rates and studying the variables that may be more predictive of high-end consumers. Distributions of fish consumption for different age cohorts, ethnic groups, socioeconomic statuses, types of fish (i.e., freshwater, marine, estuarine), and source of fish (i.e., store-bought versus self-caught) were derived. Consumption of fish and shellfish for those who consume both caught and bought fish is higher than those who reported eating only bought or only self-caught. Mean fish consumption per kilogram of body weight ranged from 0.11 g/kg-day to 2.3 g/kg-day. The highest values were observed in Florida for children 1<6 years of age. The Florida data show a statistically significant increase in the percentage of the population reporting fish and shellfish consumption with an increase in household income and education. This trend was not observed in the other states.

The evolution of EPA's Exposure Factors Handbook and its future as an exposure assessment resource

The need to compile and summarize exposure factors data into a resource document was first established in 1983 after the publication of the National Academy of Sciences (NAS) report on Risk Assessment in the Federal Government: Managing the Process and subsequent publication of the Environmental Protection Agencys (EPAs) exposure guidelines in 1986 (NAS, 1983; US EPA, 1986). During the same time frame, the EPA published a report entitled Development of Statistical Distributions or Ranges of Standard Factors Used in Exposure Assessment to promote consistency among various exposure assessment activities in which EPA was involved and to serve as a support document to the 1986 exposure guidelines (US EPA, 1985). As the exposure assessment field continued to advance during the 1980s and 1990s, so did the need for more comprehensive data on exposure factors. The Exposure Factors Handbook was first published in 1989 in response to this need (US EPA, 1989). It became an important reference document and has been revised and updated since its original publication (US EPA, 1989; US EPA, 1997a; US EPA, 2011a). This paper reviews the evolution of the Exposure Factors Handbook, and explores anticipated needs and some of the potential options for future updates of the handbook.