Lactational exposure to short-chain chlorinated paraffins in China, Korea, and Japan.

To investigate short-chain chlorinated paraffin (SCCP) levels in human breast milk, pooled breast milk samples (BMSs) collected between 2007 and 2010 from Chinese (Beijing, n = 17), Korean (Seoul, Busan, n = 16), and Japanese (Kyoto, Sendai, n = 44) women were analyzed. SCCPs found in air samples in Beijing (n = 4, in 2008) were also analyzed and compared with BMSs to estimate the possible source of contamination in Beijing. The electron-capture negative ionization method demonstrated the different sensitivities for SCCPs, and pentachlorinated alkanes had the highest method detection limit (MDL) among congeners. In Beijing, SCCPs were detected in 8 of 17 pooled BMSs at concentrations more than the highest MDL of each homolog. The total SCCP concentration ranged from below the MDL to 54 ng g-1 lipid weight. Among the SCCP homologs, polychlorinated tridecanes were most frequently detected in Beijing. In Korea and Japan, no samples contained detectable total SCCP concentrations at more than the highest MDL. In Seoul, only two samples showed trace levels of polychlorinated undecanes. In Kyoto and Sendai, congeners of polychlorinated dodecanes were most frequently detected. C10 components were the major contributors to the SCCPs in the atmosphere of Beijing. Congener profiles in breast milk in Beijing provided a clear contrast to the profiles found in food and air. The unique congener profiles necessitate the monitoring of breast milk for exposure of infants to SCCPs. The calculated mean exposure of SCCPs in 1-year-olds in China was 337 ng (kg body weight)-1 d-1. These results demonstrate the body burden of SCCPs in the study areas and potential lactational exposure to SCCPs in Asian countries.

Biological Monitoring of Human Exposure to Neonicotinoids Using Urine Samples, and Neonicotinoid Excretion Kinetics.

BACKGROUND: Neonicotinoids, which are novel pesticides, have entered into usage around the world because they are selectively toxic to arthropods and relatively non-toxic to vertebrates. It has been suggested that several neonicotinoids cause neurodevelopmental toxicity in mammals. The aim was to establish the relationship between oral intake and urinary excretion of neonicotinoids by humans to facilitate biological monitoring, and to estimate dietary neonicotinoid intakes by Japanese adults. METHODOLOGY/PRINCIPAL FINDINGS: Deuterium-labeled neonicotinoid (acetamiprid, clothianidin, dinotefuran, and imidacloprid) microdoses were orally ingested by nine healthy adults, and 24 h pooled urine samples were collected for 4 consecutive days after dosing. The excretion kinetics were modeled using one- and two-compartment models, then validated in a non-deuterium-labeled neonicotinoid microdose study involving 12 healthy adults. Increased urinary concentrations of labeled neonicotinoids were observed after dosing. Clothianidin was recovered unchanged within 3 days, and most dinotefuran was recovered unchanged within 1 day. Around 10% of the imidacloprid dose was excreted unchanged. Most of the acetamiprid was metabolized to desmethyl-acetamiprid. Spot urine samples from 373 Japanese adults were analyzed for neonicotinoids, and daily intakes were estimated. The estimated average daily intake of these neonicotinoids was 0.53-3.66 µg/day. The highest intake of any of the neonicotinoids in the study population was 64.5 µg/day for dinotefuran, and this was <1% of the acceptable daily intake.

Post-Accident Sporadic Releases of Airborne Radionuclides from the Fukushima Daiichi Nuclear Power Plant Site.

The Fukushima nuclear accident (March 11, 2011) caused the widespread contamination of Japan by direct deposition of airborne radionuclides. Analysis of weekly air filters has revealed sporadic releases of radionuclides long after the Fukushima Daiichi reactors were stabilized. One major discharge was observed in August 2013 in monitoring stations north of the Fukushima Daiichi nuclear power plant (FDNPP). During this event, an air monitoring station in this previously scarcely contaminated area suddenly reported (137)Cs activity levels that were 30-fold above the background. Together with atmospheric dispersion and deposition simulation, radionuclide analysis in soil indicated that debris removal operations conducted on the FDNPP site on August 19, 2013 are likely to be responsible for this late release of radionuclides. One soil sample in the center of the simulated plume exhibited a high (90)Sr contamination (78 ± 8 Bq kg(-1)) as well as a high (90)Sr/(137)Cs ratio (0.04); both phenomena have usually been observed only in very close vicinity around the FDNPP. We estimate that through the resuspension of highly contaminated particles in the course of these earthmoving operations, gross (137)Cs activity of ca. 2.8 × 10(11) Bq has been released.

Short-chain chlorinated paraffins in cooking oil and related products from China.

Short-chain chlorinated paraffins (SCCPs) are emerging persistent organic pollutants. It has been found that dietary intakes of SCCPs in China have recently increased and are now higher than in Japan and Korea. The contribution of cooking oil to dietary exposure to SCCPs in China was evaluated by analyzing SCCPs in cooking oil, raw seeds used to produce cooking oil, and fried confectionery products collected in China in 2010 and 2012. Detectable amounts of SCCP homologs were found in 48 out of the 49 cooking oil samples analyzed, and the SCCP concentrations varied widely, from <9 to 7500 ng g(-1). Estimated dietary intakes of total SCCPs in cooking oil ranged from <0.78 to 38 µg d(-1). The estimated dietary intake of SCCPs was relatively high (mean 14.8 µg d(-1)) for residents of Beijing. Fried confectionery was found to contain SCCP concentrations of 11-1000 ng g(-1). Cooking oil might therefore be one of the sources of SCCPs to Chinese diets. SCCPs were also detected in raw seeds used to produce cooking oil, but the concentrations varied widely. The SCCP homolog patterns in the raw seed and cooking oil samples were different, implying that the seeds used to produce the oil (and therefore the soil on which the seeds were produced) were unlikely to be the sources of SCCPs in cooking oil. Further investigations are needed to determine the routes through which cooking oil becomes contaminated with SCCPs during the production and processing of the oil.

Perfluorinated carboxylic acids discharged from the Yodo River Basin, Japan.

We investigated perfluorinated carboxylic acids (PFCAs) with 7-14 carbon atoms (C7-C14) in the Yodo River system in 2013. C7-C11 were detected at most sampling sites. The range and median of total PFCAs (ΣPFCAs) concentrations were 1.0-89.7 and 11.2 ng L(-1), respectively. The dominant component was C8 (average for all samples=53.3±8.8%), followed by C7 (19.2±6.7%) and C9 (17.6±7.1%). The levels of C8 were confirmed to decrease greatly over the last 10 years. We assessed the fluxes in C7-C11 discharged from the basin based on the concentrations in river water and river flow rate. The flux of discharged ΣPFCAs was 237.0 g d(-1) at the most downriver point of the assessment areas. Considering the variability in flow rate due to precipitation, the annual ΣPFCAs flux was estimated to be 86.5-173.4 kg y(-1). Identification and quantification of PFCAs sources is difficult because the strength of the sources changes with time, and available information is quite limited. Further monitoring and investigation are necessary to understand sources of PFCAs, as well as their potential for human exposure.

Toxicokinetics of perfluoroalkyl carboxylic acids with different carbon chain lengths in mice and humans.

OBJECTIVES: Perfluoroalkyl carboxylic acids (PFCAs) consist of analogs with various carbon chain lengths. Their toxicokinetics have remained unexplored except in the case of perfluorooctanoic acid (8 carbon chemicals). This study aimed to investigate the toxicokinetics of PFCAs with six to fourteen carbon atoms (C6 to C14) in mice and humans. METHODS: We applied a two-compartment model to mice administered PFCAs intravenously or by gavage. The time courses of the serum concentration and tissue distribution and elimination were evaluated for 24 hours after treatment. For human samples, urine from healthy volunteers, bile from patients who underwent biliary drainage, and cerebral spinal fluid (CSF) from brain drainage were collected. RESULTS: The mouse experiment showed that short-chained PFCAs (C6 and C7) were rapidly eliminated in the urine, whereas long-chain PFCAs (C8 to C14) accumulated in the liver and were excreted slowly in feces. Urinary clearance of PFCAs in humans also decreased with increasing alkyl chain lengths, while biliary clearances increased. C9 to C10 had the smallest total clearance for both mice and humans. However, disparities existed in the magnitude of the total clearance between mice and humans. A slightly higher partition ratio (brain/serum) was observed for long-chained PFCAs in mice, but this was not observed in the corresponding partition ratio in humans (CSF/serum). CONCLUSIONS: The large sequestration volumes of PFCAs in the liver seem to be attributable to the liver's large binding capacity in both species. This will be useful in evaluating PFCA bioaccumulation in other species.

Radiation dose rates now and in the future for residents neighboring restricted areas of the Fukushima Daiichi Nuclear Power Plant.

Radiation dose rates were evaluated in three areas neighboring a restricted area within a 20- to 50-km radius of the Fukushima Daiichi Nuclear Power Plant in August-September 2012 and projected to 2022 and 2062. Study participants wore personal dosimeters measuring external dose equivalents, almost entirely from deposited radionuclides (groundshine). External dose rate equivalents owing to the accident averaged 1.03, 2.75, and 1.66 mSv/y in the village of Kawauchi, the Tamano area of Soma, and the Haramachi area of Minamisoma, respectively. Internal dose rates estimated from dietary intake of radiocesium averaged 0.0058, 0.019, and 0.0088 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. Dose rates from inhalation of resuspended radiocesium were lower than 0.001 mSv/y. In 2012, the average annual doses from radiocesium were close to the average background radiation exposure (2 mSv/y) in Japan. Accounting only for the physical decay of radiocesium, mean annual dose rates in 2022 were estimated as 0.31, 0.87, and 0.53 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. The simple and conservative estimates are comparable with variations in the background dose, and unlikely to exceed the ordinary permissible dose rate (1 mSv/y) for the majority of the Fukushima population. Health risk assessment indicates that post-2012 doses will increase lifetime solid cancer, leukemia, and breast cancer incidences by 1.06%, 0.03% and 0.28% respectively, in Tamano. This assessment was derived from short-term observation with uncertainties and did not evaluate the first-year dose and radioiodine exposure. Nevertheless, this estimate provides perspective on the long-term radiation exposure levels in the three regions.

(137)Cs trapped by biomass within 20 km of the Fukushima Daiichi Nuclear Power Plant.

Analysis of (137)Cs trapped in biomass in highly contaminated zones is crucial in predicting the long-term fate of (137)Cs following the explosion at the Fukushima Daiichi Nuclear Power Plant. We surveyed forest 20-50 km from the plant in July and September 2011 to evaluate (137)Cs trapped in biomass within 20 km of the plant. We determined the ambient dose rate and collected forest soils and twigs at 150 sampling points. Removability from the canopy was evaluated by washing leaves and branches with water and organic solvents. The biomass of the forest canopy was then calculated. (137)Cs fallout was simulated with an atmospheric transport model. The modeled dose rate agreed with observations (n = 24) (r = 0.62; p < 0.01). Washing experiments demonstrated that unremovable portions accounted for 53.9 ± 6.4% of (137)Cs trapped by deciduous canopy (n = 4) and 59.3 ± 13.8% of (137)Cs trapped by evergreen canopy (n = 10). In total, it was estimated that 74.5 × 10(12) Bq was trapped by canopy in the forest within the no-go zone, with 44.2 × 10(12) Bq allocated to unremovable portions, and that 0.86% of the total release was trapped in biomass as of September 2011.

Preliminary assessment of ecological exposure of adult residents in Fukushima Prefecture to radioactive cesium through ingestion and inhalation.

OBJECTIVE: This study aims to estimate the ecological exposure of adult residents of Fukushima Prefecture to ¹³4cesium (Cs) and ¹³7Cs through ingestion and inhalation between July 2 and July 8, 2011. METHODS: Fifty-five sets of meals with tap water, each representing one person's daily intake, were purchased in local towns in Fukushima Prefecture. Locally produced cow's milk (21 samples) and vegetables (43 samples) were also purchased. In parallel, air sampling was conducted at 12 different sites using a high-volume sampler. Nineteen sets of control meals were collected in Kyoto in July 2011. ¹³4Cs and ¹³7Cs levels in the samples were measured using a germanium detector. RESULTS: Radioactivity was detected in 36 of the 55 sample meals from Fukushima, compared with one of 19 controls from Kyoto. The median estimated dose level (µSv/year) was 3.0, ranging from not detectable to 83.1. None of the cow's milk (21) or vegetable (49) samples showed levels of contamination above the current recommended limits (Bq/kg) of 200 for milk and 500 for vegetables. The total effective dose levels by inhalation were estimated to be <3 µSv/year at nine locations, but samples at three other locations close to the edge of the 20-km radius from the crippled nuclear power plant showed higher levels of contamination (µSv/year): 14.7 at Iitate, 76.9 at Namie, and 27.7 at Katsurao. CONCLUSIONS: Levels of exposure to ¹³4Cs and ¹³7Cs in Fukushima by ingestion and inhalation are discernible, but generally within recommended limits.

Odd-numbered perfluorocarboxylates predominate over perfluorooctanoic acid in serum samples from Japan, Korea and Vietnam.

Perfluorooctanoic acid (PFOA) has recently attracted attention as a potential health risk following environmental contamination. However, information detailing exposure to perfluorinated carboxylic acids (PFCAs) other than PFOA is limited. We measured the concentrations of PFCAs (from perfluorohexanoic acid to perfluorotetradecanoic acid) in serum samples obtained from patients in Japan (Sendai, Takayama, Kyoto and Osaka) between 2002 and 2009, Korea (Busan and Seoul) between 1994 and 2008 and Vietnam (Hanoi) in 2007/2008. Total PFCA levels (geometric mean) were increased from 8.9 ng mL(-1) to 10.3 ng mL(-1) in Japan; from 7.0 ng mL(-1) to 9.2 ng mL(-1) in Korea; and were estimated at 4.7 ng mL(-1) in Vietnam. PFCAs of greater length than PFOA were significantly increased in Sendai, Takayama and Kyoto, Japan, and levels of long-chain PFCAs exceeded PFOA levels in serum. Among these PFCAs, perfluoroundecanoic acid (PFUnDA) was the predominant component (28.5%), followed by perfluorononanoic acid (PFNA 17.5%), perfluorodecanoic acid (PFDA 7.9%), perfluorotridecanoic acid (PFTrDA 6.1%) and perfluorododecanoic acid (PFDoDA 1.8%). Odd-numbered PFCAs (PFNA, PFUnDA and PFTrDA) were also observed in Korea and Vietnam and their presence increased significantly in Korea between 1994 and 2007/2008. The proportion of long-chain PFCAs in serum was relatively high compared to reports in Western countries. Further investigations into the sources and exposure routes are needed to predict the future trajectory of these serum PFCA levels.

Environmental ecological modeling of human blood lead levels in East Asia.

Environmental ecological modeling (EEM), which unifies models simulating transport of chemicals and exposure of humans to chemicals, was used to simulate long-term trends of female adult human blood lead levels (BLLs) and historical exposure to the atmospheric lead in four East Asian countries: Japan, Korea, China, and Vietnam. Anthropogenic lead emissions to the atmosphere in Vietnam were estimated from energy statistics to be 1931 t yr(-1). Calculated BLLs generally agreed with those observed in samples collected in these countries as the error factors were less than 2. The model results revealed that BLLs decreased significantly in Tokyo (by 58%) and Seoul (by 45%) in recent decades and confirmed the effects of efforts to reduce environmental lead in Japan and Korea. The model results also revealed that BLLs in Beijing did not decrease in this decade as much as in Tokyo and Seoul, despite the phasing out of leaded gasoline, and that the contribution from the atmospheric component was increasing (43% in 2009). Finally, we applied EEM to simulate BLLs of children in Hanoi. The probability of children having BLLs greater than 50 µg L(-1) was 7.5%, which was greater than those observed in developed countries.

Long-term simulation of human exposure to atmospheric perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) in the Osaka urban area, Japan.

A publicly available atmospheric transport model, the Weather Research and Forecasting Chemistry Model ( http://ruc.noaa.gov/wrf/WG11/ ), was used to simulate atmospheric perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) emitted from a point source in the Osaka urban area (also known as Keihanshin), Japan. The time period of the simulation was from 1983 to 2008. The modeled air concentrations were highly correlated (r = 0.91) with the observed air concentrations. Intake levels by inhalation of simulated air concentrations and through the gastrointestinal tract as estimated by the food duplicate method were input to a pharmacokinetic model of the human body to simulate serum concentrations of PFOA and PFO (PFO(A)). For validation of the atmospheric model, simulated values were compared with those observed in serum samples. The simulated values generally agreed with those observed in serum samples from residents of the Keihanshin area (r = 0.93). It was confirmed that the atmospheric model was generally capable of projecting features of atmospheric PFO(A) as well as serum concentrations of PFO(A) in this case. The results indicated a dominant contribution of the atmospheric component to serum PFO(A) in humans near the point source in the Keihanshin area. In 2008, that contribution was about 70%.

Levels of perfluorooctane sulfonate and perfluorooctanoic acid in female serum samples from Japan in 2008, Korea in 1994-2008 and Vietnam in 2007-2008.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have recently received attention owing to their widespread contamination in the environment. One of major manufacturers, 3M Company voluntarily phased out PFOS production in 2002. We measured the PFOS and PFOA concentrations in serum samples from Japan (Sendai, Takayama and Osaka), Korea (Busan and Seoul) and Vietnam (Hanoi) to evaluate the possible effects of the phase-out on the serum levels. There were spatial differences in both the serum PFOS and PFOA concentrations. The serum PFOS concentrations (ngmL(-1)) evaluated as the geometric mean (geometric standard deviation) in 2007-2008 ranged from 4.86 (1.45) in Sendai, Japan, to 9.36 (1.42) in Busan, Korea. The serum PFOA concentrations ranged from 0.575 (2.32) in Hanoi, Vietnam, to 14.2 (1.73) in Osaka, Japan. Historically archived samples collected from Korea in 1994-2008 revealed that the serum PFOA concentrations increased by 1.24-fold in Busan from 2000 to 2008 and 1.41-fold in Seoul from 1994 to 2007. On the other hand, the serum PFOS concentrations did not change from 1994 to 2007/2008. The serum PFOS levels in Japan in 2008 were significantly decreased compared with previously reported values (22.3-66.7% of the values in 2003/2004). However, the serum PFOA levels showed a clear decline from 2003 to 2008 in a high-exposed area, Osaka, but not in low-exposed areas in Japan. The trends toward decreases were not uniformly observed in Asian countries, unlike the case for the United States, suggesting that local factors associated with the production and introduction histories in each country overwhelm the effects of the phase-out.