Stabilization of the As-contaminated soil from the metal mining areas in Korea

The stabilization efficiencies of arsenic (As) in contaminated soil were evaluated using various additives such as limestone, steel mill slag, granular ferric hydroxide (GFH), and mine sludge collected from an acid mine drainage treatment system. The soil samples were collected from the Chungyang area, where abandoned Au–Ag mines are located. Toxicity characteristic leaching procedure, synthetic precipitation leaching procedure, sequential extraction analysis, aqua regia digestion, cation exchange capacity, loss on ignition, and particle size distribution were conducted to assess the physical and chemical characteristics of highly arsenic-contaminated soils. The total concentrations of arsenic in the Chungyang area soil ranged up to 145 mg/kg. After the stabilization tests, the removal percentages of dissolved As(III) and As(V) were found to differ from the additives employed. Approximately 80 and 40% of the As(V) and As(III), respectively, were removed with the use of steel mill slag. The addition of limestone had a lesser effect on the removal of arsenic from solution. However, more than 99% of arsenic was removed from solution within 24 h when using GFH and mine sludge, with similar results observed when the contaminated soils were stabilized using GFH and mine sludge. These results suggested that GFH and mine sludge may play a significant role on the arsenic stabilization. Moreover, this result showed that mine sludge can be used as a suitable additive for the stabilization of arsenic.     

Laying-order effects on sperm numbers and on paternity: comparing three passerine birds with different life histories

In birds, the number of sperm trapped between the perivitelline membranes around the ovum is an estimate of sperm numbers present at the time and place of fertilisation in the female reproductive tract. Sperm numbers may vary among species and between eggs in a clutch and can provide information about sperm utilisation and mechanisms of sperm competition. Here, we describe patterns of variation in sperm numbers through the egg-laying sequence in three passerines in which extra-pair paternity is common, but copulation behaviour differs. Sperm numbers showed no systematic change across the laying sequence in blue tits (Cyanistes caeruleus), but decreased significantly with laying order in bluethroat (Luscinia svecica) and tree swallow (Tachycineta bicolor) clutches. This is consistent with observations that blue tits regularly copulate throughout the laying sequence, while bluethroats stop mate guarding and tree swallows reduce their copulation frequency once the first egg is laid. Nevertheless, cases of a sudden increase in sperm numbers in clutches of bluethroats and tree swallows suggest that successful inseminations also occurred after laying started. In blue tits and bluethroats, sperm numbers were not higher on extra-pair sired eggs than on eggs sired by the social male, suggesting that extra-pair copulations are not timed to the period of peak fertility for each egg. More extra-pair offspring originated from eggs laid early in the sequence in blue tits, while there was no systematic bias in bluethroats. Our results suggest that copulations during the laying sequence are predominantly performed by within-pair males in our study species.     

Characteristics of pollutants behavior in a stormwater constructed wetland during dry days

A stormwater wetland treating non-point source pollution (NPS) from a 64 ha agricultural watershed was monitored over a period of five months. The results indicated that pH and dissolved oxygen (DO) were increased in the wetland due to the algal growth. The highest total suspended solids (TSS) concentration was observed in the aeration pond due to the resuspension of solids, decreased in the wetland. The respective decreases in total nitrogen (TN) and total kjeldahl nitrogen (TKN) were 15.9% and 28.7% on passing through the wetland. The nitrate and ammonia were increased by 45.4% and decreased by 79.9%, respectively. These variations provided strong evidence for the existence of nitrification. The total phosphorus (TP) and phosphate had respective reductions of 52.3% and 58.2% over the wetland. The total chemical oxygen demand (TCOD) and soluble chemical oxygen demand (SCOD) were also decreased. Generally, the TN, TP and phosphate removal efficiencies were positive. These positive removal efficiencies were mainly due to microbial activities, uptake by plants, and chemical precipitation at high pH. Negative removal efficiencies can be caused by continuous rainfall activities, with short antecedent dry days (ADDs) and unstable hydraulic conditions, some other biogeochemical transformations and algal growth also being important parameters.     

Formation of dimethyldithioarsinic acid in a simulated landfill leachate in relation to hydrosulfide concentration

Dimethyldithioarsinic acid (DMDTA^V), present in such intense sources as municipal landfill leachate, has drawn a great deal of attention due to its abundant occurrence and different aspect of toxicity. The hydrosulfide (HS⁻) concentration in leachate was studied as a major variable affecting the formation of DMDTA^V. To this end, the HPLC–ICPMS system equipped with the reversed-phase C18 column was used to determine DMDTA^V. Simulated landfill leachates (SLLs) were prepared to cover a mature landfill condition with the addition of sodium sulfate and sulfide at varying concentrations in the presence of dimethylarsinic acid (DMA^V). The concentration of sodium sulfide added in the SLLs generally exhibited a strong positive correlation with the concentration of DMDTA^V. As such, the formation of DMDTA^V in the SLLs is demonstrated to be controlled by the interactive relationship between DMA^V and the HS⁻.

     

Applying models of employee identity management across cultures: Christianity in the USA and South Korea

Identity management refers to the decisions individuals make about how they present their social identities to others. We examined cross‐cultural differences in distancing and affirming identity management strategies of Christian‐identified employees utilizing samples from the USA and South Korea. Religious centrality, risks of disclosure, pressure to assimilate to organizational norms, and nation were key antecedents of chosen identity management strategies. Risks of disclosure and pressure to assimilate related to more distancing and less affirming strategies when religious centrality was low, but nation served as a boundary condition for the moderating effects of religious centrality. Distancing strategies related to negative outcomes regardless of religious centrality, but affirming strategies only related to positive outcomes when religious centrality was low. We discuss how this work contributes to theoretical and practical understanding of identity management in the workplace and across cultures. Copyright © 2014 John Wiley & Sons, Ltd.     

Long-term assessment of the environmental fate of heavy metals in agricultural soil after cessation of organic waste treatments

The current study examined the anthropogenic accumulation and natural decrease in metal concentrations in agricultural soils following organic waste application. Three common organic wastes, including municipal sewage sludge, alcohol fermentation processing sludge, and pig manure compost (PMC), were applied annually to an agricultural soil under field conditions over 7 years (1994–2000) at a rate of 12.5, 25, and 50 ton ha^?1 year^?1 and the soil accumulation of three metals of concern (Cu, Pb, and Zn) was monitored. Subsequently, organic waste amendments ceased and the experimental plots were managed using conventional fertilization for another 10 years (2001–2010) and the natural decrease in metal concentrations monitored. Although Cu and Zn concentrations in all experimental plots did not exceed the relevant guideline values (150 mg kg^?1 for Cu and 300 mg kg^?1 for Zn), significant increases in metal concentrations were observed from cumulative application of organic wastes over 7 years. For instance, PMC treatment resulted in an increase in Cu and Zn from 9.8 and 72 mg kg^?1 to 108.2 and 214.3 mg kg^?1, respectively. In addition, the natural decrease in Cu and Zn was not significant as soils amended with PMC showed only a 16 and 19 % decline in Cu and Zn concentrations, respectively, even 10 years after amendment ceased. This research suggested that more attention must be paid during production of organic waste-based amendments and at the application stage.     

Soil eaten by chacma baboons adsorbs polar plant secondary metabolites representative of those found in their diet

Geophagy, the deliberate consumption of earth materials, is common among humans and animals. However, its etiology and function(s) remain poorly understood. The major hypotheses about its adaptive functions are the supplementation of essential elements and the protection against temporary and chronic gastrointestinal (GI) distress. Because much less work has been done on the protection hypothesis, we investigated whether soil eaten by baboons protected their GI tract from plant secondary metabolites (PSMs) and described best laboratory practices for doing so. We tested a soil that baboons eat/preferred, a soil that baboons never eat/non-preferred, and two clay minerals, montmorillonite a 2:1 clay and kaolinite a 1:1 clay. These were processed using a technique that simulated physiological digestion. The phytochemical concentration of 10 compounds representative of three biosynthetic classes of compounds found in the baboon diet was then assessed with and without earth materials using high-performance liquid chromatography with diode-array detection (HPLC–DAD). The preferred soil was white, contained 1% halite, 45% illite/mica, 14% kaolinite, and 0.8% sand; the non-preferred soil was pink, contained 1% goethite and 1% hematite but no halite, 40% illite/mica, 19% kaolinite, and 3% sand. Polar phenolics and alkaloids were generally adsorbed at levels 10× higher than less polar terpenes. In terms of PSM adsorption, the montmorillonite was more effective than the kaolinite, which was more effective than the non-preferred soil, which was more effective than the preferred soil. Our findings suggest that HPLC–DAD is best practice for the assessment of PSM adsorption of earth materials due to its reproducibility and accuracy. Further, soil selection was not based on adsorption of PSMs, but on other criteria such as color, mouth feel, and taste. However, the consumption of earth containing clay minerals could be an effective strategy for protecting the GI tract from PSMs.     

Assessment of the conservation value of Munseom area in Jeju Island,South Korea

The ecosystem of munseom area (MA) in Jeju Island, one of the marine protected areas in South Korea, has been continuously threatened by lack of management and pollution of the surrounding sea area. As a result, the South Korean government is trying to implement the systematic management plan to conserve the marine ecosystem of the MA. This article tries to obtain information about the conservation value of the MA. To this end, this study examines household willingness to pay (WTP) for conserving the MA employing the contingent valuation (CV) approach. A total of 1000 South Korean households were involved in the CV survey using a dichotomous choice question. The mean yearly WTP for the conservation is estimated as KRW 1763 (USD 1.50) per household. The national value expanded from the sample to the population is worth KRW 34.0billion (USD 29.0 million) per year. The results imply that the conservation is supported by South Korean households.     

End-of-life batteries management and material flow analysis in South Korea

Analysis of collection and recycling system of end-of-life batteries was examined. Relatively limited fractions of portable batteries were collected by EPR system. More effective and diverse collection pathways should be developed. Consumers increasingly have worn-out batteries as electrical and electronic equipment with new technical developments are introduced into the market and quickly replace older models. As a result, large amounts of end-of-life (EOL) or waste batteries are generated. Such batteries may contain a variety of materials that includes valuable resources as well as toxic elements. Thus, the proper recycling and management of batteries is very important from the perspective of resource conservation and environmental effect. The collection and recycling of EOL batteries is relatively low in South Korea compared to other countries, although an extended producer responsibility (EPR) policy was adopted for battery recycling in 2003. In this study, the management and material flow of EOL batteries is presented to determine potential problems and quantitative flow, based on literature review, site visits to battery recycling facilities, and interviews with experts in the Korea Battery Recycling Association (KBRA), manufacturers, and regulators in government. The results show that approximately 558 tons of manganese-alkaline batteries, the largest fraction among recycling target items, was disposed in landfills or incinerators in 2015, while approximately 2,000 tons of batteries were recovered at a recycling facility by simple sorting and crushing processes. By raising environmental awareness, more diverse and effective collection systems could be established for consumers to easily dispose of EOL batteries in many places. Producers, retailers and distributors in South Korea should also play an important role in the collection of EOL batteries from consumers. Lithium-ion batteries from many electronic devices must be included in the EPR system for resource recovery.