Spatial distribution and temporal trends of cyclic and linear siloxanes in sediment from semi-enclosed and industrialized bays of Korea, in 2013 and 2021

Although siloxanes are contaminants of emerging concerns, limited studies have been conducted on contamination and time trends in siloxanes from aquatic environments worldwide. To date, most previous studies have focused on the environmental relevance of cyclic siloxanes in coastal environments. In the present study, cyclic and linear siloxanes were measured in sediment collected from semi-enclosed bays in Korea in 2013 and 2021 to assess occurrence, spatial distribution, temporal trends, and ecological risks. Almost all siloxanes were detected in all sediment samples, indicating continuous contamination for the last decade. The concentrations of cyclic siloxanes in sediment were approximately two times higher than those of linear siloxanes. Decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) were predominantly detected in all sediment samples, possibly due to their high consumption and strong resistance. The overall concentrations of siloxanes in sediment gradually decreased from inner to outer parts of the bays, suggesting that industrial activities largely contributed to siloxane contamination. Moreover, the highest concentrations of siloxanes in both sampling years were observed in sediment near the outfall of wastewater treatment plant, implying a potential source in the coastal environment. Siloxane concentrations in sediment were significantly correlated with sedimentary organic carbon. The concentrations of siloxanes in sediment were not significantly different between 2013 and 2021, indicating ongoing contamination. The concentrations of D5 and D6 in our sediment samples showed a limited potential to pose a threat to benthic organisms

Associations among Organochlorine Pesticides, Methanobacteriales, and Obesity in Korean Women

BACKGROUND: Although Methanobacteriales in the gut has recently been linked to obesity, no study has examined the hypothesis that waist circumference, a marker of visceral obesity, are positively associated with Methanobacteriales in the general population. Since Methanobacteriales increase in a petroleum-contaminated environment to biodegrade petroleum as one way of autopurification, we also hypothesized that high body burden of highly lipophilic petroleum-based chemicals like organochlorine pesticides (OCPs) is associated with higher levels of Methanobacteriales in the gut. METHODOLOGY/PRINCIPAL FINDINGS: Among 83 Korean women who visited a community health service center for a routine health checkup, quantitative real-time PCR (qPCR) based on 16S rDNA was used to quantify Methanobacteriales in feces. Nine OCPs were measured in both serum and feces of 16 subjects. Methanobacteriales were detected in 32.5% (27/83 women). Both BMI and waist circumference among women with Methanobacteriales were significantly higher than in women without Methanobacteriales (P = 0.04 and P = 0.01, respectively). Also, Methanobacteriales levels in feces were positively associated with BMI and waist circumference (r = +0.23 and P = 0.03 for both). Furthermore, there were significant correlations between feces Methanobacteriales levels and serum concentrations of most OCPs, including with cis-nonachlor (r = +0.53, P<0.05), oxychlordane (r = +0.46, P<0.1), and trans-nonachlor (r = +0.43, P<0.1). Despite high correlations of serum and feces concentrations of most OCPs, feces OCP concentrations were not clearly associated with feces Methanobacteriales levels. CONCLUSION/SIGNIFICANCE: In this cross-sectional study, the levels of Methanobacteriales in the human gut were associated with higher body weight and waist circumference. In addition, serum OCP concentrations were positively correlated with levels of Methanobacteriales. There may be a meaningful link among body burden of OCP, Methanobacteriales in the gut, and obesity in the general population

Multilayered Semiconductor (CdS/CdSe/ZnS)-Sensitized TiO2 Mesoporous Solar Cells: All Prepared by Successive Ionic Layer Adsorption and Reaction Processes

A model semiconductor-sensitizer layer of CdSe with under- or overlayers of CdS or ZnS by pre- or postadsorption was prepared on the surface of mesoporous TiO2 films by a series of successive ionic layer adsorption and reaction (SILAR) processes in solutions containing corresponding cations and anions. The growth of each semiconductor layer was monitored by taking UV-visible absorption spectra and high-resolution transmission electron microscopy (TEM) images. The all SILAR-prepared multicomponent sensitizer consisting of CdS/CdSe/ZnS layers was evaluated in a polysulfide electrolyte solution as a redox mediator in regenerative photoelectrochemical cells. The CdS and ZnS layers with the CdSe layer sandwiched in between were found to significantly enhance photocurrents. The best photovoltaic performance was obtained froth the CdS/CdSe/ZnS-sensitizer with the ZnS layer on the top, yielding an overall power conversion efficiency of 3.44% with a mask around the active film and 3.90% with no Mask. The effect of the mask on short-circuit current (J(sc)) and overall efficiency (eta) measurements was shown to be increasingly critical in semiconductor-sensitized solar cells as they exhibit high photocurrents. The polysulfide electrolyte, which acted as an effective electron transfer mediator for CdS and/or CdSe sensitizers, was not as effective for PbS-based sensitizers prepared by the same SILAR process.close8

Time-course uptake and elimination of benzo(a)pyrene and its damage to reproduciton and ensuing reproductive outputs of Pacific oyster, Crassostrea gigas

The time-course of uptake and elimination of benzo(a)pyrene (BaP) for the Pacific oyster, Crassostrea gigas and reproduction damage and reproductive outputs were studied. Sexually immature C. gigas broodstock were fed for 28 days with live algae grown in four BaP solutions of 0, 50, 500, and 5,000 mu g L-1 (hereafter, control, 50, 500, and 5,000 oysters) and were subsequently conditioned to maturation by a feeding with BaP-free live algae under temperature manipulation for another 28 days. The 5,000 mu g L-1 oysters gained a steady state concentration, around 30,000 ng g(-1) d.w. for digestive gland, a week earlier compared to the 500 mu g L-1 oysters. The earlier gain or longer persistence of the steady state concentration influenced elimination of BaP, with an eliminating trend for 500 mu g L-1 oysters, while no elimination for 5,000 mu g L-1 oysters. The maternal persistence of the steady state concentration resulted in significant damages in the reproductive success and their reproductive outputs in terms of the hatching rate and larval growth, survival, and settlement. The 50 mu g L-1 oysters remained far below the steady state concentration, and showed a manifest eliminating behavior during the subsequent BaP-free 28 day maturation period. The reproductive success and initial larval events of 50 mu g L-1 oysters were comparable to those of control. However, the damage potential of the 50 mu g L-1 oysters might be more significant if their maternal exposure continued beyond 28 days, since the accumulation profile at this dose was linear.X1198sciescopu

Biomagnification of persistent chlorinated and brominated contaminants in food web components of the Yellow Sea

Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) were measured in 32 species inhabiting the Yellow Sea to assess their bioaccumulation potentials. The concentrations in these samples were lower than those reported for other countries or locations. Relatively high levels of BDE 209 in biota suggest an ongoing source of deca-BDE technical mixing within the Yellow Sea. The accumulation profiles of PCBs were uniform between species, but the concentrations of OCPs and PBDEs varied widely. Pelagic and benthic food-chain components were separated by their delta C-13 values. Significant positive correlations between delta N-15 and PCB 153, PCB 138, p,p&apos;-DDE, oxy-chlordane, and trans-nonachlordane were found only for pelagic consumers, indicating that the pelagic food chain is an important bioaccumulation pathway for selected PCB and OCP compounds. The other compounds did not show any biomagnification through benthic and pelagic food chains, suggesting the lower bioaccumulation potentials of these contaminants. (C) 2013 Elsevier Ltd. All rights reserved.1189sciescopu

Psychoactive Pharmaceuticals in Sludge and Their Emission from Wastewater Treatment Facilities in Korea

Concern over the occurrence of pharmaceuticals and their metabolites in the environment is mounting due to the potential adverse effects on nontarget organisms. This study draws upon a nationwide survey of psychoactive pharmaceuticals (i.e., antischizophrenics, anxiolytics, and antidepressants) in sludge from 40 representative wastewater treatment plants (WWTPs) that receive domestic, industrial, or mixed (domestic plus industrial) wastewaters in Korea. A total of 16 psychoactive pharmaceuticals (0.12–460 ng/g dry weight) and nine of their metabolites (0.97–276 ng/g dry weight) were determined in sludge. The median concentrations of psychoactive drugs in sludge from domestic WWTPs were 1.2–3.2 times higher than the concentrations found in WWTPs that receive combined domestic and industrial wastewaters. Among the psychoactive drugs analyzed, the median environmental emission rates of alprazolam (APZ) and carbamazepine (CBZ) through domestic WWTPs (both sludge and effluent discharges combined) were calculated to be ≥15.5 μg/capita/day, followed by quetiapine (QTP; 8.51 μg/capita/day), citalopram (CLP; 5.45 μg/capita/day), and venlafaxine (VLF; 3.59 μg/capita/day). The per-capita emission rates of some of the metabolites of psychoactive drugs through WWTP discharges were higher than those calculated for parent compounds. Significant correlations (ρ = 0.432–0.780, <i>p</i> < 0.05) were found between the concentrations of typically coprescribed antischizophrenics and antidepressants in sludge. Multiple linear regression analysis of measured concentrations of drugs in sludge revealed that several WWTP parameters such as treatment capacity, population-served, sludge production rate, composition of wastewater (domestic versus industrial), and hydraulic retention time can affect the concentrations of psychoactive drugs in sludge

Free Cortisol Mediates Associations of Maternal Urinary Heavy Metals with Neonatal Anthropometric Measures: A Cross-Sectional Study

Prenatal exposure to heavy metals is known to be associated with adverse birth outcomes and oxidative stress biomarkers. In this study, we examined whether maternal free cortisol or 8-Hydroxy-2-Deoxyguanosine (8-OHdG) could mediate associations between maternal heavy metal exposure and birth outcomes. A total of 182 healthy pregnant women were recruited. Heavy metals (including Pb, Hg, and Cd), free-cortisol, and 8-OHdG were analyzed in urine at delivery. Birth outcomes including birth weight, length, Ponderal index, and head circumference were measured. To examine associations of maternal urinary heavy metals with biomarkers and birth outcomes, generalized linear models were employed. Birth length was positively associated with Pb (β = 0.78, 95% CI: 0.09–1.46) and Hg (β = 0.84, 95% CI: 0.23–1.45) (both p p < 0.05). No association between maternal Cd and birth outcomes was observed. Most heavy metals showed positive associations with free cortisol and 8-OHdG. Free cortisol was identified as a mediator underlying the observed relationship between Hg and birth length or Ponderal index. This study observed adverse birth outcomes from maternal exposures to Pb and Hg. Increased free cortisol related to Hg exposure was suggested as a possible causal pathway from Hg exposure to birth outcomes such as the Ponderal index

Polychlorinated dibenzo-p-dioxins and dibenzofurans in sediments from the southeastern coastal areas of Korea

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Occurrence of Eight Bisphenol Analogues in Indoor Dust from the United States and Several Asian Countries: Implications for Human Exposure

Bisphenol A has been reported to be a ubiquitous contaminant in indoor dust, and human exposure to this compound is well documented. Information on the occurrence of and human exposure to other bisphenol analogues is limited. In this study, eight bisphenol analogues, namely 2,2-bis(4-hydroxyphenyl)propane (BPA), 4,4'-(hexafluoroisopropylidene)diphenol (BPAF), 4,4'-(1-phenylethylidene)bisphenol (BPAP), 2,2-bis(4-hydroxyphenyl)butane (BPB), 4,4'-dihydroxydiphenylmethane (BPF), 4,4'-(1,4-phenylenediisopropylidene)bisphenol (BPP), 4,4'- sulfonyldiphenol (BPS), and 4,4'-cyclohexylidenebisphenol (BPZ), were determined in indoor dust samples (n = 156) collected from the United States (U.S.), China, Japan, and Korea. Samples were extracted by solid liquid extraction, purified by automated solid phase extraction methods, and determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The total concentrations of bisphenols (Sigma BPs; sum of eight bisphenols) in dust were in the range of 0.026-111 mu g/g (geometric mean: 2.29 mu g/g). BPA, BPS, and BPF were the three major bisphenols, accounting for >98% of the total concentrations. Other bisphenol analogues were rare or not detected, with the exception of BPAF, which was found in 76% of the 41 samples collected in Korea (geometric mean: 0.0039 mu g/g). The indoor dust samples from Korea contained the highest concentrations of both individual and total bisphenols. BPA concentrations in dust were compared among three microenvironments (house, office, and laboratory). The estimated median daily intake (EDI) of Sigma BPs through dust ingestion in the U.S., China, Japan, and Korea was 12.6, 4.61, 15.8, and 18.6 ng/kg body weight (bw)/day, respectively, for toddlers and 1.72, 0.78, 2.65, and 3.13 ng/kg bw/day, respectively, for adults. This is the first report on the occurrence of bisphenols, other than BPA, in indoor dust.Bisphenol A has been reported to be a ubiquitous contaminant in indoor dust, and human exposure to this compound is well documented. Information on the occurrence of and human exposure to other bisphenol analogues is limited. In this study, eight bisphenol analogues, namely 2,2-bis(4-hydroxyphenyl)propane (BPA), 4,4'-(hexafluoroisopropylidene)diphenol (BPAF), 4,4'-(1-phenylethylidene)bisphenol (BPAP), 2,2-bis(4-hydroxyphenyl)butane (BPB), 4,4'-dihydroxydiphenylmethane (BPF), 4,4'-(1,4-phenylenediisopropylidene)bisphenol (BPP), 4,4'- sulfonyldiphenol (BPS), and 4,4'-cyclohexylidenebisphenol (BPZ), were determined in indoor dust samples (n = 156) collected from the United States (U.S.), China, Japan, and Korea. Samples were extracted by solid liquid extraction, purified by automated solid phase extraction methods, and determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The total concentrations of bisphenols (Sigma BPs; sum of eight bisphenols) in dust were in the range of 0.026-111 mu g/g (geometric mean: 2.29 mu g/g). BPA, BPS, and BPF were the three major bisphenols, accounting for >98% of the total concentrations. Other bisphenol analogues were rare or not detected, with the exception of BPAF, which was found in 76% of the 41 samples collected in Korea (geometric mean: 0.0039 mu g/g). The indoor dust samples from Korea contained the highest concentrations of both individual and total bisphenols. BPA concentrations in dust were compared among three microenvironments (house, office, and laboratory). The estimated median daily intake (EDI) of Sigma BPs through dust ingestion in the U.S., China, Japan, and Korea was 12.6, 4.61, 15.8, and 18.6 ng/kg body weight (bw)/day, respectively, for toddlers and 1.72, 0.78, 2.65, and 3.13 ng/kg bw/day, respectively, for adults. This is the first report on the occurrence of bisphenols, other than BPA, in indoor dust