Blood lead levels of residents living around 350 abandoned metal mines in Korea

In 2007, as part of the control and prevention of environmental contamination threatening public health, the Korean Ministry of Environment planned to implement a national biomonitoring survey of three metals: lead, cadmium, and mercury in the blood of residents living near 350 abandoned metal mines known to be contaminated and as possible threats to the health of inhabitants. Thus, we investigated demographic and lifestyle variables and blood lead levels in residents living around the mines and compared them against those of control subjects. We measured the blood lead concentrations in 14,849 subjects (14,132 from nearby the 350 abandoned metal mines and 717 subjects from eight control areas). A questionnaire was provided to all subjects to determine gender, age, mining experience, period of time living in the vicinity of mines, smoking status, and personal perception of abandoned mines as a health risk. The geometric means (95% confidence intervals) of the blood lead levels of residents living around the abandoned metal mines and control areas were 3.017 (2.996-3.037 μg/dL) [female, 2.797 μg/dL (2.771-2.822 μg/dL); male, 3.330 μg/dL (3.298-3.363 μg/dL)] and 2.757 (2.677-2.837 μg/dL) [female, 2.604 μg/dL (2.506-2.700 μg/dL); male, 2.993 μg/dL (2.859-3.126 μg/dL)], respectively. Among residents of the mining areas, nonsmokers and residents who had no mining experience showed significantly lower mean blood lead levels than did smokers, past smokers, and those with mining experience. The mean blood lead concentrations of residents who expressed some concern about the abandoned mines were significantly higher than those of residents without concerns. The mean blood lead concentration of residents living around the abandoned mines was significantly higher than that of residents living in control areas as well as that of the general adult Korean population. We also confirmed that smoking is an important variable to consider, as it increases blood lead concentration.     

Biological monitoring of heavy metal contaminations using owls

Iron, manganese, copper, lead and cadmium were measured in the livers, muscles, kidneys and bones of Eurasian Eagle Owls (Bubo bubo), Brown Hawk Owls (Nixos scutulata) and Collared Scops Owls (Otus lempiji) from Korea. Iron concentrations by tissue within species did not differ, but there were significant differences among tissues across all species. Manganese and copper concentrations in muscles, kidneys and bones, but not livers, differed among species and also differed among tissues in the three owl species. We suggest that manganese and copper concentrations from this study were far below the level associated with their toxicity. Lead concentrations significantly differed among all species for livers and bones, and among tissues for each species. Cadmium concentrations were significantly different among species for all tissues and among tissues in Eurasian Eagle Owls and Collared Scops Owls. For most samples, lead concentrations in livers and bones, and cadmium in livers and kidneys, were within the background levels for wild birds. For some Eurasian Eagle Owls and Collared Scops Owls, lead concentrations were at an acute exposure level, whilst lead concentrations were at a chronic exposure level in Brown Hawk Owls. Cadmium concentrations were at a chronic exposure level in all three owl species. Acute and chronic poisoning was significantly correlated between indicator tissues. We suggest that lead and cadmium contamination in Eurasian Eagle Owls may reflect a Korean source, Brown Hawk Owls may reflect Korean and wintering sites, and Collared Scops Owls may reflect breeding and/or wintering sites.     

Changes in thyroid peroxidase activity in response to various chemicals

Thyroperoxidase (TPO) is a large heme-containing glycoprotein that catalyzes the transfer of iodine to thyroglobulin during thyroid hormone (TH) synthesis. Previously, we established an in vitro assay for TPO activity based on human recombinant TPO (hrTPO) stably transfected into human follicular thyroid carcinoma (FTC-238) cells. It is important to determine whether environmental chemicals can disrupt TPO activity because it is an important factor in the TH axis. In this study, we used our assay to examine the changes in TPO activity in response to various chemicals, including benzophenones (BPs), polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs). Overall, BPs, PAHs, and POPs slightly altered TPO activity at low doses, as compared with the positive controls methimazole (MMI), genistein, and 2,2',4,4'-tetrahydroxy BP. Benzophenone, benzhydrol, 3-methylchloranthracene, pyrene, benzo(k)fluoranthene, benzo(e)pyrene, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and heptachlor decreased TPO activity, while 2,4-dihydroxy BP, 2,2'-dihydroxy-4-methoxy BP, and dibenzo(a,h)anthracene increased TPO activity. From these data, we can predict the disruption of TPO activity by various chemicals as a sensitive TH end point. TPO activity should be considered when enacting measures to regulate environmental exposure to thyroid-disrupting chemicals.     

Effect of dibenzopyrene measurement on assessing air quality in Beijing air and possible implications for human health

Size fractionated particulate matter (PM) was collected in summer and winter from Beijing, China for the characterization of an expanded list of PAHs and evaluation of air pollution metrics. Summertime ΣPAHs on PM was 14.6 ± 29(PM 1.5), 0.88 ± 0.49(PM 1.5-7.2) and 0.29 ± 0.076(PM 7.2) ng m(-3) air while wintertime concentrations were 493 ± 206(PM 1.5), 26.7 ± 14(PM 1.5-7.2) and 5.3 ± 2.5(PM 7.2) ng m(-3) air. Greater than 90% of the carcinogenic PAHs were concentrated on PM(1.5). Dibenzopyrene isomers made up a significant portion (～30%) of the total carcinogenic PAH load during the winter. To our knowledge, this is the first report of dibenzopyrenes in the Beijing atmosphere and among the few studies that report these highly potent PAHs in ambient particulate matter. Lifetime risk calculations indicated that 1 out of 10,000 to over 6 out of 100 Beijing residents may have an increased risk of lung cancer due to PAH concentration. Over half of the lifetime risk was attributed to Σdibenzopyrenes. The World Health Organization and Chinese daily PM(10) standard was exceeded on each day of the study, however, PAH limits were only exceeded during the winter. The outcomes of the air pollution metrics were highly dependent on the individual PAHs measured and seasonal variation.     

Bioaccumulation surveillance in Milford Haven Waterway

Biomonitoring of contaminants (metals, organotins, polyaromatic hydrocarbons (PAHs), PCBs) was undertaken in Milford Haven Waterway (MHW) and a reference site in the Tywi Estuary (St Ishmael/Ferryside) during 2007–2008. Bioindicator species encompassed various uptake routes—Fucus vesiculosus (dissolved contaminants); Littorina littorea (grazer); Mytilus edulis and Cerastoderma edule (suspension feeders); and Hediste (=Nereis) diversicolor (sediments). Differences in feeding and habitat preference have subtle implications for bioaccumulation trends though, with few exceptions, contaminant burdens in MHW were higher than the Tywi reference site, reflecting inputs. Elevated metal concentrations were observed at some MHW sites, whilst As and Se (molluscs and seaweed) were consistently at the higher end of the UK range. However, for most metals, distributions in MH biota were not exceptional. Several metal-species combinations indicated increases in bioavailability upstream, which may reflect the influence of geogenic/land-based sources—perhaps enhanced by lower salinity. TBT levels in MH mussels were below OSPAR toxicity thresholds and in the Tywi were close to zero. Phenyltins were not accumulated appreciably in M. edulis, whereas some H. diversicolor populations appear subjected to localized (historical) sources. PAHs in H. diversicolor were distributed evenly across most of MHW, although acenaphthene, fluoranthene, pyrene, benzo(a)anthracene and chrysene were highest at one site near the mouth; naphthalenes in H. diversicolor were enriched in the mid-upper Haven (a pattern seen in M. edulis for most PAHs). Whilst PAH (and PCB) concentrations in MH mussels were mostly above reference and OSPAR backgrounds, they are unlikely to exceed ecotoxicological thresholds. Bivalve Condition indices (CI) were highest at the Tywi reference site and at the seaward end of MH, decreasing upstream—giving rise to several significant (negative) relationships between CI and body burdens. Despite the possible influence of salinity gradient as a complicating factor, multivariate analysis indicated that a combination of contaminants could influence the pattern in condition (and the biomarkers metallothionein and TOSC). Integrating bioaccumulation data with biological and biochemical endpoints is seen as a useful way to discriminate environmental quality of moderately contaminated areas such as MHW and to prioritise cause and effect investigations.     

Characteristics of aerosol types during large-scale transport of air pollution over the Yellow Sea region and at Cheongwon,Korea, in 2008

Episodes of large-scale transport of airborne dust and anthropogenic pollutant particles from different sources in the East Asian continent in 2008 were identified by National Oceanic and Atmospheric Administration satellite RGB (red, green, and blue)-composite images and the mass concentrations of ground level particulate matter. These particles were divided into dust, sea salt, smoke plume, and sulfate by an aerosol classification algorithm. To analyze the aerosol size distribution during large-scale transport of atmospheric aerosols, aerosol optical depth (AOD) and fine aerosol weighting (FW) of moderate imaging spectroradiometer aerosol products were used over the East Asian region. Six episodes of massive airborne dust particles, originating from sandstorms in northern China, Mongolia, and the Loess Plateau of China, were observed at Cheongwon. Classified dust aerosol types were distributed on a large-scale over the Yellow Sea region. The average PM10 and PM2.5 ratio to the total mass concentration TSP were 70% and 15%, respectively. However, the mass concentration of PM2.5 among TSP increased to as high as 23% in an episode where dust traveled in by way of an industrial area in eastern China. In the other five episodes of anthropogenic pollutant particles that flowed into the Korean Peninsula from eastern China, the anthropogenic pollutant particles were largely detected in the form of smoke over the Yellow Sea region. The average PM10 and PM2.5 ratios to TSP were 82% and 65%, respectively. The ratio of PM2.5 mass concentrations among TSP varied significantly depending on the origin and pathway of the airborne dust particles. The average AOD for the large-scale transport of anthropogenic pollutant particles in the East Asian region was measured to be 0.42 ± 0.17, which is higher in terms of the rate against atmospheric aerosols as compared with the AOD (0.36 ± 0.13) for airborne dust particles with sandstorms. In particular, the region ranging from eastern China, the Yellow Sea, and the Korean Peninsula to the Korea East Sea was characterized by high AOD distributions. In the episode of anthropogenic polluted aerosols, FW averaged 0.63 ± 0.16, a value higher than that in the episode of airborne dust particles (0.52 ± 0.13) with sandstorms, showing that fine anthropogenic pollutant particles contribute greatly to atmospheric aerosols in East Asia.     

Abundance and sources of hydrophilic and hydrophobic water-soluble organic carbon at an urban site in Korea in summer

In this study, the characteristics of total water-soluble organic carbon (WSOC) and isolated WSOC fractions were examined to gain a better understanding of the pathway of organic aerosol production. 24 h PM(2.5) samples were collected during the summer (July 28-August 28, 2009) at an urban site in Korea. A glass column filled with XAD7HP resin was used to separate the filtered extracts into hydrophilic (WSOC(HPI)) and hydrophobic (WSOC(HPO)) fractions. The origins of air mass pathways arriving at the sampling site were mostly classified into three types, those originating over the East Sea of Korea that passed over the eastern inland urban and industrial regions (type I); those from the marine (western/southwestern/southern marine) and passed over the national industrial complex regions (type II); and those from northeastern China that passed through North Korea and metropolitan areas of South Korea (type III). Measurements showed an increase in the average WSOC fraction of total OC from the type II to III air mass (53 to 64%) periods. Also, higher SO(4)(2-)/SO(x) (=SO(2) + SO(4)(2-)) was observed in the type III air mass (0.70) than those in the types I (0.49) and II (0.43). According to the average values of WSOC/OC and SO(4)(2-)/SO(x), measurements suggest that the aerosols collected during the type III air mass period were more aged or photo-chemically processed than those during the types I and II air mass periods. The relationship between the SO(4)(2-)/SO(x) and WSOC/OC (R(2) = 0.64) suggests that a significant fraction of the observed WSOC at the site could be formed by an oxidation process similar to SO(4)(2-) aerosols, probably the oxidation process using OH radicals, or in-cloud processing. The photochemical production of WSOC(HPO) was also observed to significantly contribute to the total OC.     

Changes in the sorption and rate of 17β-estradiol biodegradation by dissolved organic matter collected from different water sources

The potential biodegradation and subsequent transformation of 17β-estradiol (E2) to estrone (E1) were examined in the presence of various dissolved organic matter (DOM) isolated from effluent, river and lake waters. In addition, estrogenicity was estimated in association with the removal of E2 via its sorption onto DOM and biodegradation. The more biodegradable lake-derived DOM promoted more extensive transformation of E2 into E1 than the effluent organic matter through a biodegradation process. Overall, under all conditions, biodegradation dominated the removal of E2 in water. The increased dissolved organic carbon (DOC) concentrations in river and lake-derived DOM (e.g. 6.5 mg C L(-1)) reduced the removal of E2 by decreasing its biodegradation due to the moderate sorption of E2 onto DOM. The effluent organic matter showed greater removal of E2 via biodegradation, as well as significantly high sorption. This was associated with a large amount of hydrophobic fulvic acid (FA)- and humic acid (HA)-like organic components, as shown by the small increase in the specific UV absorbance at 254 nm (SUVA(254)). An increase in the DOC concentration reduced the removal of E2, resulting in high estrogenicity. The present study suggests that both organic composition and DOC concentration influenced the removal of E2 and, therefore, should be fully considered when assessing estrogenicity and its impacts on the aquatic environment.     

Nitrosamine occurrence at Korean surface water using an analytical method based on GC/LRMS

The survey of nitrosamine occurrence at Korean surface water of Nakdong river is conducted in this study. For this purpose, the nitrosamine analytical method based on more affordable GC/LRMS (low resolution mass spectrometry) has been developed. According to the study results, six nitrosamine compounds (NDEA as N-nitrosomethylethylamine, NDPA as N-nitrosodi-n-propylamine, NDMA as N-nitrosodimethylamine, NMEA as N-nitrosomethylethylamine, NDBA as N-nitrosodi-n-butylamine, and NDPHA as N-nitrosodiphenylamine) were detected at the Nakdong river. Among these, NDEA and NDPA are the most important compounds in terms of the nitrosamine contamination of the Nakdong river. The detected concentration of NDEA exceeded the CDHCS (California Department of Health Care Services) response level of 100 ng/L at several sites. The detected concentration of NDPA approached the response level (500 ng/L) at a few sites. When all nitrosamine concentrations were summed up, the maximum concentration of 735.7 ng/L was detected at the Nakdong river. An equation describing a decrease in total nitrosamine concentration along downstream sampling sites was proposed in this study. The equation can be used to predict the downstream nitrosamine contamination at the Nakdong river. Among various water quality parameters, T-N showed a good correlation with total nitrosamine concentration.     

Supervisor expediency to employee expediency: The moderating role of leader–member exchange and the mediating role of employee unethical tolerance

We utilize social learning theory to test the role‐modeling effect of supervisor expediency (i.e., a supervisor's use of unethical practices to expedite work for self‐serving purposes). In particular, we examine the relationship between supervisor expediency and employee expediency, as moderated by leader–member exchange (LMX) and mediated by employee unethical tolerance. We predict that employees are more likely to model their supervisors' expedient behaviors when their relationship is characterized by high‐LMX (a high‐quality exchange relationship that is rich in socioemotional support). Furthermore, we argue that supervisor expediency, especially when LMX is high, influences employees' attitudes of unethical tolerance, which then affects employees' expedient behaviors. Across 2 multisource field studies and a third time‐lagged field study, we found general support for our theoretical predictions. Theoretical and practical implications are discussed.