Estimated Exposure Doses Research Articles

Clinical effects of unintentional pediatric buprenorphine exposures: experience at a single tertiary care center

Context: Exploratory buprenorphine ingestions in young children have been associated with clinically significant toxicity. However, detailed data on the clinical presentation and management of these patients are lacking. In an attempt to obtain more comprehensive data, we sought to examine a single center cohort of patients with report of buprenorphine exposure and provide descriptive analysis of rates of respiratory depression, time to respiratory depression, interventions, disposition, and outcomes.Study design: We performed a retrospective cohort study at a single pediatric tertiary care center of children between the age of 6 months and 7 years of age hospitalized between 1 January 2006 and 1 September 2014 with report of buprenorphine or buprenorphine/naloxone exposure. Patients with possible exposure to more than one agent were excluded. We extracted clinical findings, including time to respiratory depression, interventions, and disposition from the medical record.Results: Eighty-eight patients met the inclusion criteria. Seven patients were excluded. The median age was 24 months [IQR 18–30]. 20 patients (23%) received activated charcoal while 48 (55%) were treated with naloxone. 36 (41%) patients were admitted to the ICU. Observed clinical effects included respiratory depression (83%), oxygen saturation by pulse oximetry (SpO2) < 93% (28%), depressed mental status (80%), miosis (77%), and emesis (45%). Median time from exposure to respiratory depression was 263 min [IQR 105–486]. The median hospital length of stay was 22 h [IQR 20–26] and was positively associated with estimated exposure dose (p = 0.002).Conclusion: Pediatric patients exposed to buprenorphine are likely to exhibit signs and symptoms of opioid toxicity, including respiratory depression, altered mental status and miosis. Although the majority of patients developed signs of clinical toxicity within 8 h of reported exposure, the optimum duration of monitoring remains unclear.

Diphenhydramine exposure in dogs: 621 cases (2008-2013).

OBJECTIVE To characterize the signalment, dose response, and clinical signs of diphenhydramine toxicosis in dogs. DESIGN Retrospective case series. ANIMALS 621 dogs with diphenhydramine exposure. PROCEDURES The electronic medical record database for an animal poison control center was reviewed from January 2008 through December 2013 to identify dogs that had ingested or been injected with diphenhydramine. Information extracted from the records and evaluated included the signalment, clinical signs observed, and estimated exposure dose of diphenhydramine. Clinical signs were categorized as none, mild, moderate, and severe. RESULTS The mean ± SEM age of dogs was 3.6 ± 0.1 years (range, 0.1 to 16 years). Diphenhydramine exposure was by ingestion for 581 (93.6%) dogs and injection for 40 (6.4%) dogs. Only 146 (23.5%) dogs developed ≥ 1 clinical signs of toxicosis, the most common of which were associated with the nervous (lethargy, hyperactivity, agitation, hyperthermia, ataxia, tremors, and fasciculations) or cardiovascular (tachycardia) systems, and 3 dogs died. Although the presence and extent of clinical signs varied greatly among dogs, the exposure dose of diphenhydramine was positively associated with the severity of clinical signs in a dose-dependent manner regardless of the route of exposure (ingestion or injection). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dogs exposed to diphenhydramine developed clinical signs of toxicosis fairly infrequently, and those clinical signs were generally mild and primarily affected the neurologic and cardiovascular systems. Supportive treatment for diphenhydramine toxicosis should be administered on the basis of the clinical signs observed.

Organophosphorus flame retardants and phthalate esters in indoor dust from different microenvironments: Bioaccessibility and risk assessment

Incidental ingestion of indoor dust is an important pathway for human exposure to organophosphorus flame retardants (OPFRs) and phthalate esters (PAEs). However, little is known about their bioaccessibility in indoor dust. In this study, indoor dust samples were collected from houses, offices, public microenvironments (PMEs), and university dorms, and physiologically based extraction test (PBET) was used to measure the bioaccessibility of OPFRs and PAEs in these dust samples. Total concentrations of OPFRs in dust samples ranged from 0.01 to 63.2 μg g−1, with significantly lower concentrations in dorm dust (median = 0.30 μg g−1) than those in houses (3.12), offices (5.94), and PMEs (11.6). Total PAEs ranged from 5.49 to 2161 μg g−1 with significantly lower concentrations in dorm dust (379 μg g−1) than those in the other three types of dust (767, 515, and 731 μg g−1). When subject to PBET, the bioaccessibility of OPFRs ranged from 8.18% (triphenyl phosphate) to 54.5% (Tris(2-chloroisopropyl) phosphate) for OPFRs, and from 1.21% (di-2-ethylhexyl phthalate, DEHP) to 81.1% (dimethyl phthalate) for PAEs. Estimated exposure doses for adults and infants to OPFRs via dust ingestion were much lower than the reference doses (RfD), but intake dose of DEHP for infants was higher than the RfD of 20 μg kg−1 d−1. However, the DEHP intake dose did not exceed the RfD after incorporating bioaccessibility into risk assessment. Our data indicated the importance of considering contaminant bioaccessibility during risk assessment of indoor dust.

Levels of polybrominated diphenyl ethers in indoor dust and human exposure estimates from Makurdi, Nigeria

Information on polybrominated diphenyl ethers (PBDEs) in the indoor environment in developing countries is still relatively scarce. In this study, house (n=10) and office (n=11) dusts samples collected from Makurdi, Benue State Nigeria were extracted and analysed for most abundant PBDEs congeners in the environment. Soxhlet extraction followed by GC-EIMS was employed for the measurement of PBDEs (BDE-47, -100, -99, -154, -153, -183 and -209). The mean concentration of ∑7 PBDEs ranged from 57ngg−1 to 80ngg−1 and a median value of 45ngg−1and 63ngg−1 were obtained for house and office dust respectively. The daily exposure and ingestion dose estimates were calculated based on the assumption that 30mg and 60mgday−1 dust represent the ingestion rate. In addition, the corresponding time spent indoors was assumed to be 87.5% (adult) and 69% (children) in homes and 22% in offices and day care. The average value exposure rate of ∑7PBDEs for children and adults were 2ngday−1 and 0.84ngday−1 respectively. The results in the present study, showed higher exposure estimates for both children and adults’ in house dust from Nigeria compared to South Africa.

Ceramics manufacturing contributes to ambient silica air pollution and burden of lung disease.

Inhalation of silica (SiO2) in occupational exposures can cause pulmonary fibrosis (silicosis), lung function deficits, pulmonary inflammation, and lung cancer. Current risk assessment models, however, cannot fully explain the magnitude of silica-induced pulmonary disease risk. The purpose of this study was to assess human health risk exposed to airborne silica dust in Taiwan ceramics manufacturing. We conducted measurements to characterize workplace-specific airborne silica dust in tile and commodity ceramic factories and used physiologically based alveolar exposure model to estimate exposure dose. We constructed dose-response models for describing relationships between exposure dose and inflammatory responses, by which health risks among workers can be assessed. We found that silica contents were 0.22-33.04 % with mean concentration ranges of 0.11-5.48 and 0.46-1763.30 μg m(-3), respectively, in commodity and tile ceramic factories. We showed that granulation workers in tile ceramic factory had the highest total SiO2 lung burden (∼1000 mg) with cumulative SiO2 lung burden of ∼4 × 10(4) mg-year. The threshold estimates with an effect on human lung inflammation and fibrosis are 407.31 ± 277.10 (mean ± sd) and 505.91 ± 231.69 mg, respectively. For granulation workers, long-term exposure to airborne silica dust for 30-45 years was likely to pose severe adverse health risks of inflammation and fibrosis. We provide integrated assessment algorithms required to implement the analyses and maintain resulting concentration of silica dust at safety threshold level in the hope that they will stimulate further analyses and interpretation. We suggest that decision-makers take action to implement platforms for effective risk management to prevent the related long-term occupational disease in ceramics manufacturing.

Reduction factors for wooden houses due to external γ-radiation based on in situ measurements after the Fukushima nuclear accident.

For estimation of residents' exposure dose after a nuclear accident, the reduction factor, which is the ratio of the indoor dose to the outdoor dose is essential, as most individuals spend a large portion of their time indoors. After the Fukushima nuclear accident, we evaluated the median reduction factor with an interquartile range of 0.43 (0.34–0.53) based on 522 survey results for 69 detached wooden houses in two evacuation zones, Iitate village and Odaka district. The results indicated no statistically significant difference in the median reduction factor to the representative value of 0.4 given in the International Atomic Energy Agency (IAEA)-TECDOC-225 and 1162. However, with regard to the representative range of the reduction factor, we recommend the wider range of 0.2 to 0.7 or at least 0.2 to 0.6, which covered 87.7% and 80.7% of the data, respectively, rather than 0.2 to 0.5 given in the IAEA document, which covered only 66.5% of the data. We found that the location of the room within the house and area topography, and the use of cement roof tiles had the greatest influence on the reduction factor.

Assessment of ultrafine particles in Portuguese preschools: levels and exposure doses

The aim of this work was to assess ultrafine particles (UFP) number concentrations in different microenvironments of Portuguese preschools and to estimate the respective exposure doses of UFP for 3-5-year-old children (in comparison with adults). UFP were sampled both indoors and outdoors in two urban (US1, US2) and one rural (RS1) preschool located in north of Portugal for 31 days. Total levels of indoor UFP were significantly higher at the urban preschools (mean of 1.82 × 10(4) and 1.32 × 10(4) particles/cm(3) at US1 an US2, respectively) than at the rural one (1.15 × 10(4) particles/cm(3) ). Canteens were the indoor microenvironment with the highest UFP (mean of 5.17 × 10(4) , 3.28 × 10(4) , and 4.09 × 10(4) particles/cm(3) at US1, US2, and RS1), whereas the lowest concentrations were observed in classrooms (9.31 × 10(3) , 11.3 × 10(3) , and 7.14 × 10(3) particles/cm(3) at US1, US2, and RS1). Mean indoor/outdoor ratios (I/O) of UFP at three preschools were lower than 1 (0.54-0.93), indicating that outdoor emissions significantly contributed to UFP indoors. Significant correlations were obtained between temperature, wind speed, relative humidity, solar radiation, and ambient UFP number concentrations. The estimated exposure doses were higher in children attending urban preschools; 3-5-year-old children were exposed to 4-6 times higher UFP doses than adults with similar daily schedules. This study reports information on ultrafine particles (UFPs) in various indoor and outdoor microenvironments (canteens, classrooms, gymnasiums, and outdoor) of urban and rural preschools. It identifies the potential sources and origins, characterizes the influence of meteorological parameters on UFP levels, and performs a comparison with other existing international studies. To this date, relatively few studies have investigated UFP in preschools (none in Portugal) and none assessed exposure dose for different age-groups. The obtained findings showed that levels of UFP in various microenvironments of schools differed significantly. Therefore, to obtain an accurate representation of child’s overall preschool exposure profiles, the exposures occurring in these different microenvironments should be always accounted for.

Evaluation of Environmental Contamination and Estimated Exposure Doses after Residents Return Home in Kawauchi Village, Fukushima Prefecture

The external and internal exposure doses due to artificial radionuclides after the return of residents to their homes in Kawauchi Village, Fukushima Prefecture, including the restricted area within a 20-km radius from the Fukushima Dai-ichi Nuclear Power Plant (FNPP), were evaluated by gamma spectrometry of the soils and local agricultural products. The prevalent dose-forming artificial radionuclides from all samples were determined to be (134)Cs and (137)Cs (radiocesium). The estimated external effective doses from soils sampled on December 24 and 25, 2012 were 0.0017-9.2 mSv/y in the areas within a 20- to 30-km radius from the FNPP and 0.39-1.3 mSv/y in the areas within a 20-km radius from the FNPP. These levels appeared to be decreasing, despite the distance from the FNPP (median: 0.21 (0.012-0.56) mSv/y), compared to the levels just before the return of the residents to their homes on December 19 and 20, 2011 (median: 0.85 (0.40-1.4) mSv/y). The committed effective doses from the local agricultural samples in Kawauchi Village from May 1, 2012 to March 31, 2013 were sufficiently low, in the range of 18-44 μSv/y for males and 20-48 μSv/y for females (the range was 18-48 μSv/y for children and 25-43 μSv/y for adults), compared to the public dose limit (1 mSv/y, ICRP, 1991), although the potential for radiation exposure still exists. Residents who have not yet returned may be able to return to their homes with a long-term follow-up of environmental monitoring and countermeasures to reduce unnecessary radiation exposure.

Biodosimetry of Restoration Workers for The Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Station Accident

The biological dose of nuclear workers engaged in emergency response tasks at Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Station was estimated in the present study. As the national core center for radiation emergency medical preparedness in Japan, the National Institute of Radiological Sciences (NIRS) received all individuals who were suspected of being overexposed to acute radiation. In the course of health examinations at NIRS, biological dosimetry was performed by the dicentric chromosome assay (DCA). Twelve individuals were examined from 21 March-1 July 2011. The results indicated that the estimated exposure doses for all individuals were lower than 300 mGy, with the mean value of about 101 mGy. These results by DCA were in accordance with those obtained by physical dosimetry based on personal dosimeter recording assessment. The results corroborate the fact that no acute radiation syndrome was observed among the workers examined.

The fluoride contamination in groundwater and assessment of fluoride exposure for residents in Tay Son, Binh Dinh

This study focuses on determining the concentration of fluoride in groundwater and estimating the fluoride exposure through drinking water of three different age-groups for residents in Tay Son district, Binh Dinh province. A total of 50 well-water samples were collected and 220 people were surveyed by questionnaire from 50 households at 3 communes: Tay Phu, Binh Tuong, Tay Giang of Tay Son district. Results of this study showed that fluoride concentrations in well-water varied from 0.31 mg/L to 7.69 mg/L (mean 2.66 mg/L, SD: 2.18 mg/L) with 70% of the well-water samples above the maximum permissible limit of 1.5 mg/L (QCVN 09:2008/BTNMT). Groundwater in the studied area is seriously contaminated with fluoride. Exposure of fluoride among three age-groups was calculated according to the guidance of United States Environmental Protection Agency (US EPA). The maximum estimated exposure doses of 0.721 mg/kg/day in the age-group of below 6 year, 0.530 mg/kg/day in the age-group between 6 and 12 years and 0.320 mg/kg/day in the age-group above 12 year exceed the LOAEL value of 0.1 mg/kg/day (WHO, 1984). A health risk due to fluorosis to the people in Tay Son district has become an evidence.

Assessing Human Carcinogenic Risk of Heavy Metal Exposure in a Tourist Area

Environmental safety in a tourism area is one of the basic security for tourists health. Thus, it is of great significance to assess the heavy metal-based potential health risk of a tourism area and its surrounding areas. This study mapped the carcinogenic risk of heavy metal polluted soil in a tourism area of XX City through procedures including on-site sampling, exposure dose estimation, toxicity assessment, carcinogenic risk calculation, and GIS (Geographic Information System) spatial interpolation. Results show that the soil of the tourism area was contaminated by heavy metals such as As, Cd. The maximum Cd concentration in soil was 41.60 times more than the second level of Soil Environmental Quality Standard of China (SEQSC). Meanwhile, the carcinogenic risk of heavy metal polluted soil is much higher than the international acceptable limits (i.e. 1.0E-06) with maximum risk value at 148.7E-06. Source contribution analysis also disclosed that the carcinogenic risk in the tourism area is mainly attributed to As. It therefore can be concluded that As and Cd polluted soil in the tourism area of XX City needs to be recovered immediately in order to protect tourists health.

Human health risk assessment of occupational and residential exposures to dechlorane plus in the manufacturing facility area in China and comparison with e-waste recycling site

A screening level human health risk assessment based on the worst-case scenario was conducted on the occupational and residential exposures to dechlorane plus (DP) in the manufacturing facility region and an electronic-waste (e-waste) recycling site in China, which are two of the most polluted areas of DP in the world. Total estimated exposure doses (EEDs) via dietary intake, dermal contact, and inhalation was approximately 0.01mgkg−1d−1 for people living in the manufacturing facility region. In comparison, total EEDs (approximate 0.03μgkg−1, d−1) were 300-fold lower in people living near an e-waste recycling site in China. Chronic oral, dermal, and inhalation reference doses (RfDs) were estimated to be 5.0, 2.0, and 0.01mgkg−1d−1, respectively. The oral RfD was markedly greater than Mirex (2×10−4mgkg−1d−1) and decabromodiphenyl ether (BDE-209; 7×10−3mgkg−1d−1), which have been or might be replaced by DP as a flame retardant with less toxicity. Monte Carlo simulation was used to generate the probability densities and functions for the hazard index which was calculated from the EEDs and RfDs to assess the human health risk. The hazard index was three orders of magnitude lower than 1, suggesting that occupational and residential exposures were relatively safe in the manufacturing facility region and e-waste recycling site.

Estimation of Exposure Dose Due to Radon in Radioactive Spring Water

Estimation of Exposure Dose Due to Radon in Radioactive Spring Water

Fluoride in groundwater, dates and wheat: Estimated exposure dose in the population of Bushehr, Iran

The goal of this study was to estimate the daily fluoride intake for residents of Bushehr province in southern Iran by determining their exposure to fluoride through consumption of drinking water, dates and wheat. The fluoride concentration of drinking water in this region varies between 0.5 and 3.0mg/L, with an average of 1.6mg/L; and 44.4% of the drinking water exceed the guideline value of 1.5mg/L recommended by WHO. The average fluoride content of dates is 10.0mg/kg; whereas wheat roots and shoots contain an average of 30.0 and 19.0mgF−/kg, respectively. The estimated intake from drinking water is 0.12mg/kg/d for children (20kg body weight) and 0.05mg/kg/d for adults (70kg body weight). The total estimated fluoride intake (from drinking water and dates) for children is 0.17mg/kg/d. Thus, dates contribute an average 30% to the daily fluoride intake in the population. The maximum estimated fluoride intake (from dates and drinking water) for children and adults are 3.4 and 1.6 times higher, respectively, than the minimum risk level of 0.05mg/kg/d calculated by Agency for Toxic Substances and Disease Registry.

Establishment and verification of dose effect relation curves between T cell receptor gene mutation frequency and ionizing radiation dose

To establish the dose-effect curve between TCR MF and ionizing radiation. Peripheral lymphocytes were collected from 8 healthy adults (4 males and 4 females) and cultured in vitro with 12 well culture plates. They were stimulated by PHA-P and IL-2 after exposed to different doses of irradiation (0.00 - 8.00 Gy) and cultured for 7 d. The dose-effect curve was established after measuring TCR MF using flow cytometry. Also, using the same method, we separated and cultured the peripheral lymphocytes collected from 16 radiotherapy cancer patients, whose radiation styles and doses were different, and then measured TCR MF to estimate the whole equivalent dose of radiotherapy patients through the dose-effect curve. Peripheral blood was collected and cultured, chromosome aberration (dicentric and ring) was determined under microscope to estimate irradiation dose. The relationship of dose-effect between the TCR MF and ionizing radiation (0.00 - 8.00 Gy) was well, the curve of large dose group (2.00 - 8.00 Gy), low dose group (0.00 - 1.00 Gy) and 0.00 - 8.00 Gy dose group were met with the quadratic polynomial model, the equation was TCR MF = -32.8579 + 20.5436D + 0.6341D(2), TCR MF = 1.796 + 0.017D + 5.155D(2) and TCR MF = -0.6229 + 6.305D + 0.6919D(2), respectively. D was the radiation dose (Gy). Using the established curve and the chromosome aberration method to estimate the systemic exposure dosage, the average relative deviation was 16.8%. The curve established by the TCR gene mutation analysis technology can be applied to exposure dose estimation of victims in ionization radiation accidents.

Estimation of concentration and exposure doses due to radon by using CR-39 plastic track detectors in the residences of Sudhnuti, Azad Kashmir, Pakistan

This paper presents the results of indoor radon concentration measurements in 120 dwellings of district Sudhnuti of Azad Kashmir. Measurements were taken with CR-39 passive alpha track detector. CR-39 based box type radon detectors were installed in a bedroom and living rooms of each house. The detectors were retrieved after exposing to indoor radon for period of 6 months and then etched in 6 M NaOH at 80°C for 16 h, the observed track densities were converted in to the indoor radon concentration. Indoor radon concentration varied from 20 ± 12 to 170 ± 4 Bq m−3 for the houses of the district Sudhnuti. Arithmetic mean (AM), geometric mean (GM) and geometric standard deviations (GSD) were found to be 82 ± 6, 77 ± 6 and 1.51, respectively. The minimum value of weighted average radon concentration was recorded in one of the house of Mang town, whereas the maximum value was found in the Pattan Sher Khan region. Doses due to indoor radon exposure vary from 0.50 ± 0.31 to 4.28 ± 0.11 mSv year−1 AM, GM and GSD. of mean effective doses were found to be 2.06 ± 0.13, 1.95 ± 0.18 and 1.51, respectively. According to the recommendations made by the Health Protection Agency, UK (200 Bq m−3) all the houses surveyed are within the safe limits.

One-year monthly survey of rotavirus, astrovirus and norovirus in three sewage treatment plants (STPs) in Beijing, China and associated health risk assessment

To evaluate the presence and distribution of the three main viruses (rotavirus, astrovirus, and norovirus) responsible for human acute gastroenteritis in sewerage systems, a one-year study was carried out in Beijing, China. A total of 96 samples of influent and effluents from three sewage treatment plants (STPs) were collected from November 2006 to October 2007. Silica was used to concentrate viral particles from water samples and a reverse transcriptase-nested polymerase chain reaction (RT-nested PCR) method was used for detection of viruses. Virus(es) could be detected in 35.4% (34/96) of the water samples analysed, where human rotavirus was the most frequently detected one (32.3%, 31/96), followed by human astrovirus (6.3%, 6/96) and human norovirus (3.1%, 3/96). According to the quantitation results of rotaviruses, which were gained by the real-time quantitative RT-PCR method with SYBR Green I, it was known that the distributions of rotaviruses in influents and effluents of three STPs were quite similar, i.e., abundant in cold weather (from October to March) and less prevalent in warm weather (from April to September). According to the estimated exposure dose and exposure frequency, as well as the acceptable annual risk level, it was shown that the rotaviruses in the reused wastewater after conventional treatment process presented potential risk to human health through both occupational and accidental exposure.

Perchlorate exposure and dose estimates in infants.

Perchlorate is a naturally occurring inorganic anion used as a component of solid rocket fuel, explosives, and pyrotechnics. Sufficiently high perchlorate intakes can modify thyroid function by competitively inhibiting iodide uptake in adults; however, little is known about perchlorate exposure and health effects in infants. Food intake models predict that infants have higher perchlorate exposure doses than adults. For this reason, we measured perchlorate and related anions (nitrate, thiocyanate, and iodide) in 206 urine samples from 92 infants ages 1-377 days and calculated perchlorate intake dose for this sample of infants. The median estimated exposure dose for this sample of infants was 0.160 μg/kg/day. Of the 205 individual dose estimates, 9% exceeded the reference dose of 0.7 μg/kg/day; 6% of infants providing multiple samples had multiple perchlorate dose estimates above the reference dose. Estimated exposure dose differed by feeding method: breast-fed infants had a higher perchlorate exposure dose (geometric mean 0.220 μg/kg/day) than infants consuming cow milk-based formula (geometric mean 0.103 μg/kg/day, p < 0.0001) or soy-based formula (geometric mean 0.027 μg/kg/day, p < 0.0001), consistent with dose estimates based on dietary intake data. The ability of perchlorate to block adequate iodide uptake by the thyroid may have been reduced by the iodine-sufficient status of the infants studied (median urinary iodide 125 μg/L). Further research is needed to see whether these perchlorate intake doses lead to any health effects.

Occurrence of Phthalate Metabolites in Human Urine from Several Asian Countries

The occurrence of 14 phthalate metabolites was found in human urine samples collected from seven Asian countries: China, India, Japan, Korea, Kuwait, Malaysia, and Vietnam. Phthalate metabolites were found in all samples, indicating widespread exposure of humans to phthalates in these Asian countries. The highest total (the sum of 14 phthalates) phthalate metabolite concentrations were found in samples collected from Kuwait (median: 1050 ng/mL), followed in decreasing order by samples from India (389 ng/mL), China (234 ng/mL), Vietnam (133 ng/mL), Japan (120 ng/mL), Korea (117 ng/mL), and Malaysia (94.9 ng/mL). The creatinine-adjusted median concentrations of total phthalates for urine samples from Kuwait, India, China, Vietnam, Japan, Korea, and Malaysia were 692, 506, 289, 119, 103, 104, and 169 μg/g creatinine, respectively. Monomethyl phthalate (mMP), monoethyl phthalate (mEP), mono (2-isobutyl phthalate) (miBP), mono-n-butyl phthalate (mBP), and metabolites of di-(2-ethylhexyl) phthalate (DEHP) were the dominant compounds, collectively accounting for >95% of the total concentrations in the samples from the seven countries. The profiles of urinary phthalate metabolite concentrations varied among the samples collected from the seven countries. Urine samples from Kuwait contained the highest concentrations of mEP (median: 391 ng/mL), mBP (94.1 ng/mL), and the metabolites of DEHP (202 ng/mL), whereas samples from China and Japan contained the highest concentrations of miBP (50.8 ng/mL) and mMP (17.5 ng/mL), respectively. mEP was the predominant metabolite in urine samples from India and Kuwait (accounting for 49% of the total), mBP and miBP were the predominant compounds in samples from China (52%), and DEHP metabolites were the predominant compounds in samples from Korea (46%) and Vietnam (52%). Based on the urinary concentrations of mEP, mBP, miBP, and DEHP metabolites of the samples from the seven Asian countries, we estimated daily intake rates of diethyl phthalate (DEP), dibutyl phthalate (DBP), and DEHP. The results indicated that people in the seven Asian countries are exposed to DEP, DBP, and DEHP at levels well below the reference doses (RfD) suggested as unsafe by the U.S. Environmental Protection Agency (EPA). The estimated exposure doses to DEHP in Kuwait, however, were above the RfD recommended by the EPA.

Occurrence of Bisphenol A in Indoor Dust from Two Locations in the Eastern United States and Implications for Human Exposures

Bisphenol A (BPA) is used in the production of polycarbonate plastics and epoxy resins, which are used in many consumer products. Sources of human exposures to BPA include packaged and canned food products, indoor air, and dust ingestion. Information on the relative contributions of the pathways to BPA exposures is limited. In this study, we measured concentrations BPA in indoor dust collected from two locations in the Eastern United States and evaluated the contribution of dust to total BPA exposures. BPA was found in 95% of the dust samples analyzed (n = 56) at concentrations ranging from <0.5 to 10,200 ng/g (mean 843; median 422). The median values for BPA intake by way of the ingestion of dust by adults and toddlers were calculated to be 0.35 and 5.63 ng/kg body weight/day. These estimated exposure doses of BPA through dust ingestion are of the same order of magnitude as the recently reported low concentrations that induced health effects in laboratory animal studies. The contribution of dust to total human BPA intake was estimated to be <1%, however, suggesting that dietary intake is the predominant source of exposures in humans.