Comparisons of polybrominated diphenyl ethers levels in paired South Korean cord blood, maternal blood, and breast milk samples

Polybrominated diphenyl ethers (PBDEs), commonly used flame retardants, have been reported as potential endocrine disruptor and neurodevelopmental toxicants, thus giving rise to the public health concern. The goal of this study was to investigate the relationship between umbilical cord blood, maternal blood, and breast milk concentrations of PBDEs in South Korean. We assessed PBDE levels in paired samples of umbilical cord blood, maternal blood, and breast milk. The levels of seven PBDE congeners were measured in 21 paired samples collected from the Cheil Woman’s Hospital (Seoul, Korea) in 2008. We also measured thyroid hormones levels in maternal and cord blood to assess the association between PBDEs exposure and thyroid hormone levels. However, there was no correlation between serum thyroxin (T4) and total PBDEs concentrations. The total PBDEs concentrations in the umbilical cord blood, maternal blood, and breast milk were 10.7 ± 5.1 ng g⁻¹ lipid, 7.7 ± 4.2 ng g⁻¹ lipid, and 3.0 ± 1.8 ng g⁻¹ lipid, respectively. The ranges of total PBDE concentrations observed were 2.28-30.94 ng g⁻¹ lipid in umbilical cord blood, 1.8-17.66 ng g⁻¹ lipid in maternal blood, and 1.08-8.66 ng g⁻¹ lipid in breast milk. BDE-47 (45-73% of total PBDEs) was observed to be present dominantly in all samples, followed by BDE-153. A strong correlation was found for major BDE-congeners between breast milk and cord blood or maternal blood and cord blood samples. The measurement of PBDEs concentrations in maternal blood or breast milk may help to determine the concentration of PBDEs in infant.     

Reduced sulfur compounds in ambient air surrounding an industrial region in Korea

The atmospheric concentrations of several reduced sulfur compounds (RSCs) including H(2)S, CH(3)SH, DMS, CS(2), and DMDS were measured concurrently from a series of field campaigns covering multiple locations in the surroundings of a large industrial region (August 2004 to September 2005). These field studies have been designed and undertaken to inspect the concentrations of RSCs in ambient air. The RSC concentrations were found to occur in a highly variable range. H(2)S (1.06 +/- 2.07 ppb) was found to be the most abundant RSC followed by CS(2) (0.84 +/- 0.54 ppb), DMDS (0.36 +/- 1.21 ppb), DMS (0.24 +/- 0.83 ppb), and CH(3)SH (0.11 +/- 0.23 ppb). The RSC levels measured at the study area were comparable to those observed previously from other polluted environmental settings. When these RSC data were examined further in terms of spatial (industrial vs. non-industrial sites) and seasonal (summer vs. winter seasons) grouping schemes, differences in their concentration levels were statistically insignificant in most cases. In contrast, there were fairly strong variations in temporal patterns over a diurnal cycle. If these RSC concentration data were converted to diagnose the malodor strengths, their effects were in most cases insignificant with minor contribution towards odor nuisances.     

Assessment of toxic heavy metals in urban lake sediments as related to urban stressor and bioavailability

Aquatic pollution pose a serious challenge to the scientific community worldwide, since lakes or reservoirs find multifarious use and most often their water is used for drinking, bathing, irrigation, and aquaculture. Nine metals and several physicochemical parameters, from four sampling sites in a tropical lake receiving the discharges from a thermal power plant, a coal mine, and a chlor-alkali industry, were studied from 2004 to 2005. Pertaining to metal pollution, the site most polluted with heavy metals was Belwadah, i.e., waters and sediments had the highest concentration of all the metals examined. The reference site was characterized by the presence of low concentrations of metals in waters and sediments. Following the water quality monitoring, 2-month field phytoremediation experiments were conducted using large enclosures at the discharge point of different polluted sites of the lake. During field phytoremediation experiments using aquatic macrophytes, marked percentage reduction in metals concentrations were recorded. The percentage decrease for different metals was in the range of 25% to 67.90% at Belwadah (with Eichhornia crassipes and Lemna minor), 25% to 77.14% at Dongia nala (with E. crassipes, L. minor and Azolla pinnata), and 25% to 71.42% at Ash pond site of G.B. Pant Sagar (with L. minor and A. pinnata). Preliminary studies of polluted sites are useful for improved microcosm design and for the systematic extrapolation of information from experimental ecosystems to natural ecosystems.     

Assessment of trace metals in four bird species from Korea

In birds, heavy metal concentrations are influenced by diet intake, migratory pattern, and residence time. In the present study, heavy metal concentrations (in microgram per gram dry weight) were measured in livers of four bird species from Korea. Iron concentrations were greater in Eurasian Woodcocks (Scolopax rusticola) than in Grey Herons (Ardea cinerea), Little Egrets (Egretta garzetta), and Schrenck’s Bitterns (Ixobrychus eurhythmus). Copper concentrations in Grey Herons were significantly higher than in other species. Lead concentrations were greater in Schrenck’s Bitterns and Eurasian Woodcocks than in Grey Herons and Little Egrets. Eurasian Woodcocks had higher cadmium concentrations than in other species. Zinc and manganese concentrations did not differ among species. Iron, zinc, manganese, and copper concentrations from this study were within the range of other Korean bird studies, and these concentrations were far below toxic levels. Cadmium and lead accumulation trends in each species were different, and the results might be associated with their migration pattern and residence time in Korea. Grey Herons, Little Egrets, and Schrenck’s Bitterns are usually summer visitors, and Eurasian Woodcocks are passage migrants. But herons and egrets were collected in spring, autumn, and winter, but not during breeding season. They might be residents, so they could more reflect Korean cadmium and lead contaminations than Schrenck’s Bitterns. However, Eurasian Woodcocks could more reflect habitats outside Korea because of their short staying time in Korea.     

Effect of Solvent Composition on Porosity,Surface Morphology and Thermal Behavior of Metal Alginate Prepared from Algae (<Emphasis Type="Italic">Undaria pinnatifida</Emphasis>)

Alginates, extracted from algae are linear unbranched polymers containing β-(1→4)-linked d-mannuronic acid (M) and α-(1→4)-linked l-guluronic acid (G) residues. The conversion of alginic acid into the metal alginate is confirmed using FTIR spectroscopy. Asymmetric and symmetric stretching of free carboxyl group present in metal alginate occurs almost at the same position in various solvent compositions. Total intrusion volume of metal alginate prepared in propanol (0.0742 mL/g) is greater compared to those in ethanol (0.0648 mL/g) and methanol (0.0393 mL/g) as solvent. Surface morphology as well as porosity and pore size distribution of metal alginate are greatly influenced by solvent. It can be seen from thermal analysis results that calcium alginate prepared using different solvent compositions started decomposing at 100 °C, but rapid degradation started around 200 °C. The results showed a stepwise weight loss during thermal sweep, indicating different types of reactions during degradation. First and second step of rapid degradation was situated around 200–300 and 300–550 °C, respectively; whereas the final step is situated around 550–650 °C. The trend of degradation was similar for all the solvents, although the amount of final residue varied from one solvent to another. At the same time, lower thermal stability was also observed with higher heating rates. Additionally, a kinetic analysis was performed to fit with TGA data, where the entire degradation process has been considered as three consecutive first order reactions.     

Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions

With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO(2) emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) is attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH(4) production yield (MPY) and VS reduction achieved in this condition were 5.0m(3)/m(3)/d, 0.25 m(3) CH(4)/g COD(added), and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m(3)/m(3)/d, MPY of 0.26 m(3) CH(4)/g COD(added), and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to 60%, there was a significant performance drop, which was attributed to free ammonia inhibition. The performances in these two reactors were comparable to the ones achieved in the conventional wet digestion and thermophilic dry digestion processes.     

A real-time monitoring and assessment method for calculation of total amounts of indoor air pollutants emitted in subway stations

Subway systems are considered as main public transportation facility in developed countries. Time spent by people in indoors, such as underground spaces, subway stations, and indoor buildings, has gradually increased in the recent past. Especially, operators or old persons who stay in indoor environments more than 15 hr per day usually influenced a greater extent by indoor air pollutants. Hence, regulations on indoor air pollutants are needed to ensure good health of people. Therefore, in this study, a new cumulative calculation method for the estimation of total amounts of indoor air pollutants emitted inside the subway station is proposed by taking cumulative amounts of indoor air pollutants based on integration concept. Minimum concentration of individual air pollutants which naturally exist in indoor space is referred as base concentration of air pollutants and can be found from the data collected. After subtracting the value of base concentration from data point of each data set of indoor air pollutant, the primary quantity of emitted air pollutant is calculated. After integration is carried out with these values, adding the base concentration to the integration quantity gives the total amount of indoor air pollutant emitted. Moreover the values of new index for cumulative indoor air quality obtained for 1 day are calculated using the values of cumulative air quality index (CAI). Cumulative comprehensive indoor air quality index (CCIAI) is also proposed to compare the values of cumulative concentrations of indoor air pollutants. From the results, it is clear that the cumulative assessment approach of indoor air quality (IAQ) is useful for monitoring the values of total amounts of indoor air pollutants emitted, in case of exposure to indoor air pollutants for a long time. Also, the values of CCIAI are influenced more by the values of concentration of NO2, which is released due to the use of air conditioners and combustion of the fuel. The results obtained in this study confirm that the proposed method can be applied to monitor total amounts of indoor air pollutants emitted, inside apartments and hospitals as well. Implications: Nowadays, subway systems are considered as main public transportation facility in developed countries. Time spent by people in indoors, such as underground spaces, subway stations, and indoor buildings, has gradually increased in the recent past. Especially, operators or old persons who stay in the indoor environments more than 15 hr per day usually influenced a greater extent by indoor air pollutants. Hence, regulations on indoor air pollutants are needed to ensure good health of people. Therefore, this paper presents a new methodology for monitoring and assessing total amounts of indoor air pollutants emitted inside underground spaces and subway stations. A new methodology for the calculation of cumulative amounts of indoor air pollutants based on integration concept is proposed. The results suggest that the cumulative assessment approach of IAQ is useful for monitoring the values of total amounts of indoor air pollutants, if indoor air pollutants accumulated for a long time, especially NO2 pollutants. The results obtained here confirm that the proposed method can be applied to monitor total amounts of indoor air pollutants emitted, inside apartments and hospitals as well.     

Analysis of injury mechanism of the elderly and non-elderly groups in minor motor vehicle accidents

Abstract

Objective: The purpose of this study is to investigate the injury patterns of noncatastrophic accidents by individual age groups.

Methods: Data were collected from the Korean In-Depth Accident Study database based on actual accident investigation. The noncatastrophic criteria were classified according to U.S. experts from the Centers for Disease Control and Prevention’s recommendations for field triage guidelines of high-risk automobile crash criteria by vehicle intrusions more than 12 in. on occupant sites (including the roof) and more than 18 in. on any site. The Abbreviated Injury Scale (AIS) was used to determine injury patterns for each body region. Severely injured patients were classified as Maximum Abbreviated Injury Scale (MAIS) 3 or higher.

Results: In this study, the most significant injury regions were the head and neck, extremities, and thorax. In addition, the incidence of severe injury among elderly patients was nearly 1.6 times higher than that of non-elderly patients. According to age group, injured body regions among the elderly were the thorax, head and neck, and extremities, in that order. For the non-elderly groups, these were head and neck, extremities, and thorax. Severe injury rates were slightly different for the elderly group (head and neck, abdomen) and non-elderly group (thorax, head and neck).

Conclusions: In both age groups, the rate of severe injury is proportional to an increase in crush extent zone. Front airbag deployment may have a relatively significant relationship to severe injuries.     

Influence of ship emissions on ozone concentrations around coastal areas during summer season

The influence of ship emissions on ozone (O₃) concentrations in a coastal area (CA) including Busan port, Korea was examined based on a numerical modeling approach during a high O₃ episode. The analysis was performed by two sets of simulation scenarios: (1) with ship emissions (e.g., TOTAL case) and (2) without ship emissions (e.g., BASE case). A process analysis (PA) (the integrated processes rate (IPR) and integrated reaction rate (IRR) analyses) was used to evaluate the relative contributions of individual physical and chemical processes in O₃ production in and around the CA (e.g., sites of Dong Sam (DS) and Dae Yeon (DY)). The model study suggested the possibility that pollutant gases emitted from the ships traversing Busan port can exert a direct impact on the O₃ concentration levels in the CA. Largest impacts of ship emissions on the O₃ concentrations were predicted at the coast (up to 15 ppb) and at inland locations (about 5 ppb) due to both the photochemical production of pollutant gases emitted from the ships and meteorological conditions. From the PA, the photochemical production of O₃ (P(O₃)) due to ship emissions in the CA was found to increase by a mean of 1.5 ppb h^?1 (especially by ≥10 ppb h^?1 at the DS site) during the day.