Anaerobic biodegradability and methanogenic toxicity of key constituents in copper chemical mechanical planarization effluents of the semiconductor industry

Copper chemical mechanical planarization (CMP) effluents can account for 30-40% of the water discharge in semiconductor manufacturing. CMP effluents contain high concentrations of soluble copper and a complex mixture of organic constituents. The aim of this study is to perform a preliminary assessment of the treatability of CMP effluents in anaerobic sulfidogenic bioreactors inoculated with anaerobic granular sludge by testing individual compounds expected in the CMP effluents. Of all the compounds tested (copper (II), benzotriazoles, polyethylene glycol (M(n) 300), polyethylene glycol (M(n) 860) monooleate, perfluoro-1-octane sulfonate, citric acid, oxalic acid and isopropanol) only copper was found to be inhibitory to methanogenic activity at the concentrations tested. Most of the organic compounds tested were biodegradable with the exception of perfluoro-1-octane sulfonate and benzotriazoles under sulfate reducing conditions and with the exception of the same compounds as well as Triton X-100 under methanogenic conditions. The susceptibility of key components in CMP effluents to anaerobic biodegradation combined with their low microbial inhibition suggest that CMP effluents should be amenable to biological treatment in sulfate reducing bioreactors.     

Determination of cytotoxicity of nephrotoxins on murine and human kidney cell lines

The present study investigates renal inner medullary collecting duct (mIMCD3) cells and human embryonic kidney cells (HEK293) for evaluation of cytotoxicity of nephrotoxic compounds. The 24 h LC(50) values for cisplatin, paraquat and ibuprofen in mIMCD3 cells were 135, 155 and 3600 microM, respectively. The 24 h LC(50) values for paraquat and ibuprofen in HEK293 cells were 180 and 1000 microM, respectively. Effects of hyperosmolality on cytotoxicity of paraquat were additive in mIMCD3 cells. These data demonstrate that renal hyperosmolality has an additive effect on cytoxicity of paraquat.     

So far,so good: Up to now,the challenge–hindrance framework describes a practical and accurate distinction

There are many ways to categorize work‐related stressors, and in recent years, a common distinction in occupational health psychology is between stressors viewed as challenges versus hindrances. Is this a useful conceptualization that provides practical and theoretical implications for IO psychologists? As Kurt Lewin famously prescribed, “there is nothing so practical as a good theory,” and we discuss the challenge–hindrance framework as a developing theory that can be useful for researchers and practitioners. We note that some of the early thinking and development of the challenge–hindrance distinction relied on both resource and appraisal theories of stress. Overall, we find that the challenge–hindrance distinction can be viewed as a framework that is useful by producing interesting, valuable, and innovative research. Simply striving to find meaningful and useful categorizations of stressors can lead us to discover new insights into the occupational stress domain, and the challenge–hindrance categories have already spurred a great deal of research.     

Urban Streamflow Response to Imported Water and Water Conservation Policies in Los Angeles,California

Los Angeles has a long history of importing water; however, drought, climate change, and environmental mitigation have forced the City to focus on developing more local water sources (target of 50% local supply by 2035). This study aims to improve understanding of water cycling in Los Angeles, including the impacts of imported water and water conservation policies. We evaluate the influence of local water restrictions on discharge records for 12 years in the Ballona Creek (urban) and Topanga Creek (natural) watersheds. Results show imported water has significantly altered the timing and volume of streamflow in the urban Ballona watershed, resulting in runoff ratios above one (more streamflow than precipitation). Further analysis comparing pre‐ vs. during‐mandatory water conservation periods shows there is a significant decrease in dry season streamflow during‐conservation in Ballona, indicating that prior to conservation efforts, heavy irrigation and other outdoor water use practices were contributing to streamflow. The difference between summer streamflow pre‐ vs. during‐conservation is enough to serve 160,000 customers in Los Angeles. If Los Angeles returns to more watering days, educating the public on proper irrigation rates is critical for ensuring efficient irrigation and conserving water; however, if water restrictions remain in place, the City must take the new flow volumes into account for complying with water quality standards in the region.     

Learning-by-catching: uncertain invasive-species populations and the value of information

This paper develops a model of invasive species control when the species’ population size is unknown. In the face of an uncertain population size, a resource manager's species-control efforts provide two potential benefits: (1) a direct benefit of possibly reducing the population of invasive species, and (2) an indirect benefit of information acquisition (due to learning about the population size, which reduces uncertainty). We provide a methodology that takes into account both of these benefits, and show how optimal management decisions are altered in the presence of the indirect benefit of learning. We then apply this methodology to the case of controlling the Brown Treesnake (Boiga irregularis) on the island of Saipan. We find that the indirect benefit—the value of information to reduce uncertainty—is likely to be quite large.     

Primate Conservation along the Tana River, Kenya: An Examination of the Forest Habitat

The Tana River National Primate Reserve, Kenya, was established in 1976 to preserve the endemic and endangered Tana River red colobus ( Colobus badius rufomitratus ) and crested mangabey ( Cercocebus galeritus galeritus ). Between 1975 and 1985 their populations declined by 80% and 45%, respectively. A study addressing primate-to-habitat relationships was conducted in 12 forest areas to determine what attributes appear most important to the in situ preservation of both endangered primates. Correlations among the abundances of primate groups, their group sizes, and the structural, resource, disturbance, and spatial attributes of the forest were used to distinguish the quality of forest patches. Intraforest habitat quality was examined, using canonical variate analysis to discriminate primate ranging patterns based on canopy and subcanopy tree composition. The colobus and mangabey show positive relationships to interior-forest habitat and appear susceptible to forest disturbances that reduce forest area or that increase forest edge and intraforest disturbance. Forest loss, fragmentation, and consequent reduction in the area-to-perimeter ratio of the remaining forests measured from 1960 to 1975 provide a partial explanation for the decline in primate populations. The results suggest that a combination of primary food items and seasonal food resources in large, high-stature, closed-canopy forests is the best predictor of high-quality habitat for these monkeys. Stewardship should be directed at the preservation of these areas or the restoration of forests toward this habitat model