Indoor House Dust Research Articles

Total and Extractable Heavy Metals in Indoor, Outdoor and Street Dust from Aswan City, Egypt

AbstractThe level of heavy metal contamination in indoor room dust is evaluated and its relationship to the external environment examined. Samples of outdoor fallen dust, indoor room dust and street dust were collected from two different environmental locations in Aswan city, Egypt. Total and extractable (soluble) concentrations of cadmium, lead, iron, and manganese were determined in the three types of dust samples. The measurements of the metal contents were preformed using atomic absorption spectroscopy. The aims of this study are: (a) to assess the influence of urban traffic on the heavy metal content in house and street dust, and (b) to determine and compare the soluble fractions of the metals in indoor house dust, outdoor fallen dust and street dust. The results showed widespread heavy metal contamination, especially Pb, Mn, and Fe, which were present as the highest values in the outdoor fallen dust, indoor and street dust, while Cd was the lowest content metal present. In general, indoor and outdoor concentration ratios varied widely from one metal to another and from one residence to another. An enrichment factor for metal explained the originality of these metals. Traffic near the two studied buildings reflects the presence of Pb in outdoor fallen dust, indoor room dust and street dust in those residences. Soluble fractions of the studied heavy metals seem to be at the lower values compared to total metal concentration present.

Use of the IEUBK Model for Determination of Exposure Routes in View of Site Remediation

ABSTRACT The Integrated Exposure Uptake Biokinetic (IEUBK) model is frequently used to estimate blood lead concentrations of children exposed to lead. Simulations with the IEUBK model were run to estimate the blood lead concentration in children living in the vicinity of a non-ferrous plant, situated in Hoboken, Belgium. Concentrations in soil ranged from 59–2425 mg Pb/kg dm, average concentrations in house dust ranged from 234–73394 mg Pb/kg dm. Measured blood lead concentrations in children aged 2–7 years were between 3 and 35 μ g/dl. Exposure sources were indoor dust in the house and the school, outdoor dust and soil in the home surrounding and at the school's playground, and suspended dust in the air. Soil ingestion values and lead exposure from food were changed to Flemish values. The model was able to predict the measured blood lead concentrations adequately except for the lowest exposure group. Predictions showed a systematic overestimation. Analysis of the data revealed that the neighbourhood's school is an important source of exposure to lead; indoor house dust dominates exposure for children going to school outside the area, because of the high concentrations of lead in indoor dust (3 to 5 times higher than in outdoor soil).

An observational study of the potential exposures of preschool children to pentachlorophenol, bisphenol-A, and nonylphenol at home and daycare

The Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study investigated the potential exposures of 257 preschool children, ages 1 1 2 - 5 yr , and their primary adult caregivers to more than 50 anthropogenic chemicals. Field sampling took place in selected counties in North Carolina (NC) and Ohio (OH) in 2000–2001. Over a 48-h period in each child's daycare center and/or home, food, beverages, indoor air, outdoor air, house dust, soil, participants’ hand surfaces and urine were sampled. Additional samples—transferable residues, food preparation surface wipes, and hard floor surface wipes—were collected in the approximately 13% of the homes that had pesticide applications within the 7 days prior to field sampling. Three phenols were among the measured chemicals: pentachlorophenol (PCP), bisphenol-A [2,2-bis(4-hydroxyphenyl)propane], and nonylphenol (4- n-nonylphenol). Nonylphenol (NP) was detected in less than 11% of the samples in any medium. Among samples that were collected at all participants’ homes and daycare centers, PCP was detected in >50% of indoor air, outdoor air, house dust, and urine samples; bisphenol-A (BPA) was detected in >50% of indoor air, hand wipe, solid food, and liquid food samples. The concentrations of the phenols in the sampled media were measured, and the children's potential exposures and potential absorbed doses resulting from intake through the inhalation, dietary ingestion, and indirect ingestion routes of exposure were estimated. The children's potential exposures to PCP were predominantly through inhalation: 78% in NC and 90% in OH. In contrast, their potential exposures to BPA were predominantly through dietary ingestion: 99%, for children in both states. The children's estimated exposures to PCP, calculated from the amounts excreted in their urine, exceeded their estimated maximum potential intake, calculated from the multimedia PCP concentrations, by a factor greater than 10. This inconsistency for PCP highlights the need for further research on the environmental pathways and routes of PCP exposure, investigation of possible exposures to other compounds that could be metabolized to PCP, and on the human absorption, metabolism, and excretion of this phenol over time periods longer than 48 h.

A Cohort Study of Indoor Nitrogen Dioxide and House Dust Mite Exposure in Asthmatic Children

The purpose of this study was to investigate dose-response relationships between asthma symptoms and indoor nitrogen dioxide (NO2) and house dust mite allergen (HDM) in children. Asthmatic children from 18 primary schools in Adelaide, Australia, kept a daily symptoms diary over 12 weeks. Home and classroom NO2 levels were measured repeatedly in winter 2000. HDM levels were obtained from beds. Lung function tests were performed at the beginning and at the end of the study period. Data on exposure and respiratory outcomes were gathered for 174 children. For school exposure, the estimated relative symptom rate (RR) for a 10-ppb increase in NO2 for difficulty breathing during the day was 1.09 (95% confidence interval [CI] = 1.03-1.15), at night 1.11 (95% CI = 1.05-1.18), and for chest tightness at night 1.12 (95% CI = 1.07-1.17). Significant symptom rate increases were also found for kitchen NO2 exposure. This was supported by a negative dose-response relationship between percentage predicted forced expiratory volume in 1 second and NO2 (-0.39%; 95% CI = -0.76 to -0.02) for kitchen exposure. Significant threshold effects using a 10-microg/g cutoff point for HDM exposure were established in the sensitized children for nighttime wheeze (RR = 3.62, 95% CI = 1.49-8.77), daytime cough (RR = 1.64, 95% CI = 1.14-2.36), and daytime asthma attack (RR = 1.95, 95% CI = 1.06-3.60). This study has established reliable risk estimates for exacerbations of asthma symptoms in children based on dose-response investigations of indoor NO2 and HDM.

Perfluorinated Sulfonamides in Indoor and Outdoor Air and Indoor Dust: Occurrence, Partitioning, and Human Exposure

Perfluorinated alkyl sulfonamides (PFASs) which are used in a variety of consumer products for surface protection were investigated through a comprehensive survey of indoor air, house dust, and outdoor air in the city of Ottawa, Canada. This study revealed new information regarding the occurrence and indoor air source strength of several PFASs including N-methylperfluorooctane sulfonamidoethanol (MeFOSE), N-ethylperfluorooctane sulfonamidoethanol (EtFOSE), N-ethylperfluorooctane sulfonamide (EtFOSA), and N-methylperfluorooctane sulfonamidethylacrylate (MeFOSEA). Passive air samplers consisting of polyurethane foam disks were calibrated and used to conduct the indoor and outdoor survey. Indoor air concentrations for MeFOSE and EtFOSE (1490 and 740 pg m(-3), respectively) were about 10-20 times greater than outdoor concentrations, establishing indoor air as an important source to the outside environment. EtFOSA and MeFOSEA concentrations were lower in indoor air (40 and 29 pg m(-3) respectively) and below detection in outdoor air samples. For indoor dust, highest concentrations were recorded for MeFOSE and EtFOSE with geometric mean concentrations of 110 and 120 ng g(-1), while concentrations for EtFOSA and MeFOSEA were below detection and 7.9 ng g(-1) respectively. MeFOSE and EtFOSE concentrations in house dust followed levels in indoor air. However, resolution of the coupled air and dust data (for the same homes) was not successful using existing KoA-based models for surface-air exchange. The partitioning to house dust was greatly underpredicted. The difficulties with existing models may be due to the high activity coefficient of PFASs in octanol and/or a situation where the dust is greatly oversaturated with respect to the air due to components of the dust being contaminated with PFASs. A human exposure assessment based on median air and dust concentrations revealed that human exposure through inhalation (100% absorption assumed) and dust ingestion were approximately 40 and approximately 20 ng d(-1), respectively. However, for children the dust ingestion pathway was dominant and accounted for approximately 44 ng d(-1).

Lessons Learned for the Assessment of Children’s Pesticide Exposure: Critical Sampling and Analytical Issues for Future Studies

In this article we examine sampling strategies and analytical methods used in a series of recent studies of children’s exposure to pesticides that may prove useful in the design and implementation of the National Children’s Study. We focus primarily on the experiences of four of the National Institute of Environmental Health Sciences/U.S. Environmental Protection Agency/ Children’s Centers and include University of Washington studies that predated these centers. These studies have measured maternal exposures, perinatal exposures, infant and toddler exposures, and exposure among young children through biologic monitoring, personal sampling, and environmental monitoring. Biologic monitoring appears to be the best available method for assessment of children’s exposure to pesticides, with some limitations. It is likely that a combination of biomarkers, environmental measurements, and questionnaires will be needed after careful consideration of the specific hypotheses posed by investigators and the limitations of each exposure metric. The value of environmental measurements, such as surface and toy wipes and indoor air or house dust samples, deserves further investigation. Emphasis on personal rather than environmental sampling in conjunction with urine or blood sampling is likely to be most effective at classifying exposure. For infants and young children, ease of urine collection (possible for extended periods of time) may make these samples the best available approach to capturing exposure variability of nonpersistent pesticides; additional validation studies are needed. Saliva measurements of pesticides, if feasible, would overcome the limitations of urinary metabolite-based exposure analysis. Global positioning system technology appears promising in the delineation of children’s time–location patterns.

Multipathway organophosphorus pesticide exposures of preschool children living in agricultural and nonagricultural communities

Environmental measurements of organophosphorus (OP) pesticides were conducted in the homes of 13 children, who lived either in the Seattle metropolitan area or in the agricultural region of Washington State, to ascertain exposure through multiple pathways. Each home was sampled for two 24-h periods during two seasons, summer and fall. Samples included 24-h indoor air, drinking water, soil, house dust, and hand and toy wipes and 24-h duplicate diets. At least one OP pesticide was found in each of the matrices sampled except for drinking water. Half of the indoor air samples contained detectable levels of chlorpyrifos or diazinon. Detectable levels of diazinon and azinphosmethyl in house dust were found in most of the agricultural homes, whereas only diazinon was found in the Seattle homes in the summer. Quantifiable chlorpyrifos and azinphosmethyl were found on either agricultural children's hands or their toys. These findings suggest different exposure pathways for children living in agricultural and nonagricultural regions.

Japanese cedar pollen in floating indoor house dust after a pollinating season

ABSTRACT Background Approximately 16.2% of the Japanese population suffers from pollinosis. One of the forms of management is self-care (preventive care), which can be categorized as 'indoor' and 'outdoor'. Outdoor self-care is usually emphasized, but indoor self-care is also important. Considerable pollen is found in indoor dust and this is thought to be one of the factors that worsens pollinosis and enables it to persistent for a long time, even after the pollinating period has finished. Taking this into consideration, we investigated the dynamic state of indoor pollen. Methods Floating indoor house dust was collected in Petri dishes. The amount of pollen in the house dust samples collected was measured using an LCD laboratory highly sensitive Cry j1 assay kit. Results The results showed that, indoors, a lot of Japanese cedar pollen (JCP) was found on the floor (tatami mats, carpets), sofas and curtains. The number of JCP in living rooms peaked in April after the pollinating period and decreased gradually; however, JCP was still found indoors, even as late as the following February. Floating JCP in the house was one-tenth of the JCP levels on the floor. Floating JCP increased on days with low humidity. Air conditioning temporarily increased levels of floating JCP in houses with an air conditioner, but the level of floating JCP decreased rapidly compared with the level of that in houses without an air conditioner. Nasal signs and symptoms disappeared completely at a level of 30 floating pollen counts/day per Petri dish. Conclusion Considerable JCP was found floating indoors with house dust after a pollinating season.

The correlations between heavy metals in residential indoor dust and outdoor street dust in Bahrain

The lead, zinc, cadmium, chromium, and nickel contents in both indoor house dust and outdoor street dust from 76 sites in Bahrain were determined by ICP-ES. The results showed widespread heavy metal contamination, especially lead, with an overall mean value in house dust for Pb, Zn, Cd, Cr, and Ni of 517, 202, 1.9, 11, and 10, respectively. The mean values in street dust were 742, 67, 1.5, 9.6, and 12 mg/kg, respectively. The major source of metals in street dust was automobile exhaust. The major source of heavy metals indoors was also from automobile dust, i.e., lead and nickel. With respect to zinc, cadmium, and chromium, indoor sources were more important than outdoor sources. The distribution of lead both indoors and outdoors in Bahrain showed high levels of contamination occurring generally in the north and northeastern part where traffic is concentrated. The levels of these toxic metals found in indoor house dust may be a significant source of exposure, especially for children.

Microenvironmental analysis of residential exposure to chromium-laden wastes in and around New Jersey homes.

The purpose of this study was to identify the significant microenvironments that can lead to chromium exposure in Hudson County, New Jersey residential settings near or on soil contaminated with chromium waste. Measurements were made in indoor air, outdoor air, and house dust. Surface dust was found to be the best index of potential Cr exposure. The values of Cr in Hudson County household dust ranged from 3.25-320 ng/cm2 in wipe samples and 1.0-12 ng/cm2 in vacuum samples. Elevated Cr in household dust was found to be related to residential locations near large chromium waste sites, household cleaning habits, and house renovation activities. Outdoor Cr air levels were similar to those obtained in other urban areas at these seasons of the year, approximately 5-7 ng/m3. Comparisons with measurements of the Cr levels in urine found that the elevated Cr in dust was associated with elevated excretion of Cr. Site-specific Cr differences in household dust suggest different sources and routes of exposure. Within the total group of homes in the present study, Cr in household dust was the major influence on household exposure.