Effects of Livestock Grazing and Well Construction on Prairie Vegetation Structure Surrounding Shallow Natural Gas Wells

Short and sparse vegetation near shallow gas wells has generally been attributed to residual effects from well construction, but other mechanisms might also explain these trends. We evaluated effects of distance to shallow gas wells on vegetation and bare ground in mixed-grass prairies in southern Alberta, Canada, from 2010 to 2011. We then tested three hypotheses to explain why we found shorter vegetation and more bare ground near wells, using cattle fecal pat transects from 2012, and our vegetation quadrats. We evaluated whether empirical evidence suggested that observed patterns were driven by (1) higher abundance of crested wheatgrass (Agropyron cristatum) near wells, (2) residual effects of well construction, or (3) attraction of livestock to wells. Crested wheatgrass occurrence was higher near wells, but this did not explain effects of wells on vegetation structure. Correlations between distance to wells and litter depth were the highest near newer wells, providing support for the construction hypothesis. However, effects of distance to wells on other vegetation metrics did not decline as time since well construction increased, suggesting that other mechanisms explained observed edge effects. Cattle abundance was substantially higher near wells, and this effect corresponded with changes in habitat structure. Our results suggest that both residual effects of well construction and cattle behavior may explain effects of shallow gas wells on habitat structure in mixed-grass prairies, and thus, to be effective, mitigation strategies must address both mechanisms.     

Use of physical properties to predict the effects of tillage practices on organic matter dynamics in three Illinois soils

This work builds on a previous study of long-term tillage trials that found use of no-tillage (NT) practices increased soil organic carbon (SOC) sequestration at Monmouth, IL (silt loam soil) by increasing the soil's protective capacity, but did not alter SOC storage in DeKalb, IL (silty clay loam), where higher clay contents provided a protective capacity not affected by tillage. The least limiting water range (LLWR), a multi-factor index of structural quality, predicted observed soil CO2 efflux patterns. Here we consider whether LLWR can predict sequestration trends at a third site, Perry, IL (silt loam soil) where SOC content is lower and bulk density is higher than in previously considered sites, and determine whether pore size characteristics can help explain the influence use of NT practices has had on SOC sequestration at all three locations. At Perry, LLWR was again related with differences in specific soil organic carbon mineralization rates (RESPsp) (2000-2001). Reduced RESPsp rates explain increases in SOC storage under NT management observed only after 17 yr. Trends in RESPsp suggest use of NT practices only enhance physical protection of SOC where soil bulk density is relatively high (approximately 1.4 g cm(-3)). In those soils (Monmouth and Perry), use of NT management reduced the volume of small macropores (15-150 microm) thought to be important for microbial activity. Physical properties appear to determine whether or not use of NT practices will enhance C storage by increasing physical protection of SOC. By refining the functions used to compute the LLWR and our understanding of the interactions between management, pore structure, and SOC mineralization, we should be able to predict the influence of tillage practices on SOC sequestration.     

Present status of the recycling of waste electrical and electronic equipment in Korea

In Korea due to rapid economical growth followed by urbanisation, breakage of large traditional families into small nuclear families, continuous changes in equipment features and capabilities causes tremendous increase in sale of new electrical and electronic equipment (EEE) and decrease in sale of used EEE. Subsequently, the ever-increasing quantity of waste electrical and electronic equipment (WEEE) has become a serious social problem and threat to the environment. Therefore, the gradual increase in the generation of WEEE intensifies the interest for recycling to conserve the resources and protect the environment. In view of the above, a review has been made related to the present status of the recycling of waste electrical and electronic equipment in Korea. This paper describes the present status of generation and recycling of waste electrical and electronic equipment, namely TVs, refrigerators, washing machines, air conditioners, personal computers and mobile phones in Korea. The commercial processes and the status of developing new technologies for the recycling of metallic values from waste printed circuit boards (PCBs) is also described briefly. Since 1998, three recycling centers are in full operation to recycle WEEE such as refrigerators, washing machines and air conditioners, having the total capacity of 880,000 units/year. All waste TVs are recently recycled on commission basis by several private recycling plants. The recycling of waste personal computers and mobile phones is insignificant in comparison with the amount of estimated obsolete those. Korea has adopted and enforced the extended producer responsibility (EPR) system. Korea is making consistent efforts to improve the recycling rate to the standards indicated in the EU directives for WEEE. Especially environmentally friendly and energy-saving technologies are being developed to recycle metal values from PCBs of WEEE.     

Mercury flows in a zinc smelting facility in South Korea

To prepare for the international mercury convention, the characteristics of mercury emissions from a zinc smelting facility in South Korea have been reviewed and a material flow analysis (MFA) has been conducted in this research. As inputs into the mercury MFA study, zinc ores and sulfuric acid were examined, whereas wastewater sludge, effluence water, spent catalyst, and emissions from the casting and roasting processes were examined as outputs. Mercury concentrations extracted from end products like zinc ingots, cadmium ingots, and sulfuric acid were then analyzed. Our results showed that the wastewater sludge discharged from the zinc smelting process had a relatively higher concentration of mercury, indicating that the concentration of mercury was further enriched in the wastewater sludge. The wastes discharged through the zinc smelting process should be thoroughly controlled, as results of the MFA showed that approximately 89 % of the mercury contained in the original input was later found in the waste. According to this study, the higher the concentration of mercury within zinc ores at the input stage, the higher is the mercury concentration found in the wastewater sludge at the output stage.     

Morphological variation of dinoflagellate Prorocentrum lima (Ehrenberg) Dodge with geographical difference

Prorocentrum lima (Ehrenberg) Dodge, one of the cosmopolitan dinoflagellates, is basically benthic and is found on the surface of macroalgae and detritus. The identification of this species requires detailed morphological observation because of its close similarity to other benthic Prorocentrum species. The purpose of this study is to detect the morphological variability of P. lima using culture clones collected from several areas to find an adequate way of subdividing the species. In this study, 33 clones of P. lima were collected from Saipan, Tahiti, Indonesia, Japan and Bermuda, and their thecal valves and periflagellar area were observed by means of light microscopy with differential interference contrast optics and scanning electron microscopy. In general cells have two centrally located pyrenoids and a posterior nucleus. The surface of both valves has many valve pores except the center. Evenly spaced marginal pores are located along the edge of the valves. P. lima samples studied herein were subdivided into four major types (ellipsoidal, general, short, and elongate ovoid) according to their shapes, length-to-width ratio and number of valve pores. The length-to-width ratios of ellipsoidal, general, short, and elongate ovoid types were 1.32, 1.33-1.43, 1.20-1.27, and 1.53-1.60 microm respectively. Also there were slight differences in the number of valve pores. The number of valve pores examined in this study ranges from 40 to 97: ellipsoidal, general, and short ovoid types range from 40 to 91, while an elongate ovoid type ranges from 80 to 97. The combination of valve shape, number of valve pores and length-to-width ratio provides useful information on the morphological variation of P. lima.     

Recycling of cathode ray tube panel glasses as aggregates of concrete blocks and clay bricks

While the cathode ray tube (CRT) funnel containing lead could be transported to a smelting facility to recover lead, which could be an available option in domestic, a proper technology to recycle a CRT panel must be developed. Thus, it was suggested that CRT panel glass be used as aggregates of concrete blocks and clay bricks. Samples of blocks and bricks were fabricated with CRT powders and tested to measure their strength and absorption rate to determine their qualities, and environmental soundness was determined by measuring the leaching rate of hazardous metals. For concrete blocks, CRT panel glass powders incorporated as aggregates up to 40 % replacing stone powder was proposed as the proper condition for manufacturing blocks. Around 2 % of CRT panel incorporated into clay brick to substitute Kaoline was suggested to fabricate the best quality of clay brick. Results of leaching test met the criteria with much less concentration of hazardous metals, even lead compound containing in the CRT funnel. To conclude, the use of CRT panel powder after crushing it to the proper size as an aggregate of concrete blocks or clay bricks could be one of the appropriate alternatives to recycle for CRT glass waste being generated drastically in a short term.     

Quality control for coal combustion products in South Korea through assessed pozzolanic-activity index with long-term property tests

In South Korea, nine million tons of fly ash (FA) are annually produced and approximately 70 % is reutilized for industrial demand. For the prompt reuse and insufficient reclamation site, quality control of FA which is main productive construction material from coal ash is very important. Assessed Pozzolanic-activity Index (API) test which needs only 2 days for evaluation of pozzolanic reaction is currently considered as an alternative of activity index measurement. This paper aims for an applicability of API test for prompt quality control and investigation of domestic FA properties. For the work, FAs from two different power plant types are prepared, and quality tests are carried out based on Korean Standards (KS) methods and API method. Lots of test results are compared with those from API and K-value test for FA with age of 7 days–1 year. From the test results for FA aged 1 year, API results are evaluated to be closely related with those from activity index and K-value, and the correlations are improved with increasing ages regardless of plant types. The applicability of API test is verified and the reduced period of FA quality evaluation can accelerate prompt use and the related process of FA.     

Selective recovery of Cu, Zn, and Ni from acid mine drainage

In Korea, the heavy metal pollution from about 1,000 abandoned mines has been a serious environmental issue. Especially, the surface waters, groundwaters, and soils around mines have been contaminated by heavy metals originating from acid mine drainage (AMD) and mine tailings. So far, AMD was considered as a waste stream to be treated to prevent environmental pollutions; however, the stream contains mainly Fe and Al and valuable metals such as Ni, Zn, and Cu. In this study, Visual MINTEQ simulation was carried out to investigate the speciation of heavy metals as functions of pH and neutralizing agents. Based on the simulation, selective pH values were determined to form hydroxide or carbonate precipitates of Cu, Zn, and Ni. Experiments based on the simulation results show that the recovery yield of Zn and Cu were 91 and 94 %, respectively, in a binary mixture of Cu and Zn, while 95 % of Cu and 94 % of Ni were recovered in a binary mixture of Cu and Ni. However, the recovery yield and purity of Zn and Ni were very low because of similar characteristics of Zn and Ni. Therefore, the mixture of Cu and Zn or Cu and Ni could be recovered by selective precipitation via pH adjustment; however, it is impossible to recover selectively Zn and Ni in the mixture of them.     

Effects of land use change and water reuse options on urban water cycle

The aim of this article was to study the effects of land use change and water reuse options on an urban water cycle. A water cycle analysis was performed on the Goonja drainage basin, located in metropolitan Seoul, using the Aquacycle model. The chronological e ects of urbanization were first assessed for the land uses of the Goonja drainage basin from 1975 to 2005, where the ratio of impervious areas ranged from 43% to 84%. Progressive urbanization was identified as leading to a decrease in evapotranspiration (29%), an increase in surface runo (41%) and a decrease in groundwater recharge (74%), indicating a serious distortion of the water cycle. From a subsequent analysis of the water reuse options, such as rainwater use and wastewater reuse, it is concluded that wastewater reuse seemed to have an advantage over rainwater use for providing a consistent water supply throughout the year for a country like Korea, where the rainy season is concentrated during the summer monsoon.     

Applying Multi-attribute Utility Theory to Decision Making in Environmental Planning: A Case Study of the Electric Utility in Korea

This paper applies the multi-attribute utility theory (MAUT) to obtaining value judgments concerning the significance of environmental impacts to achieve integration of environmental concerns at an early stage of planning, using the electric utility of Korea as a specific case study. An environmental multi-attribute index is constructed as a multi-attribute utility function, based on value judgments provided by a group of experts related to electric utility and a decision maker from Korea Electric Power Corporation (KEPCO). The societal values are derived from examining trade-offs between environmentalindex and money. The implications of the results for KEPCO are also discussed. We found that the work and results can provide valuable insights and decision opportunities for major decision making in environmental planning facing KEPCO.