Denitrification with acrylonitrile as a substrate using pure bacteria cultures isolated from acrylonitrile-butadiene-styrene wastewater

This study attempted to isolate and identify the denitrifying bacteria that utilize acrylonitrile as a substrate from acrylonitrile-butadiene-styrene (ABS) resin wastewater. The performance of the denitrifying bacteria for treating different initial acrylonitrile concentrations was also investigated under anoxic conditions. The results showed that seven strains of denitrifying bacteria that can use acrylonitrile or acrylic acid as a substrate were isolated from the denitrification tank of a wastewater treatment plant in a ABS resin manufacturing plant and a lab-scale anoxic granular activated carbon-fluidized bed. The bacteria strains Acidovorax facilis B and Pseudomonas nautica could utilize acrylonitrile up to 279 mg/l as a substrate for denitrification. For complete nitrate removal, an adequate supply of acrylonitrile was necessary. Under the assumption that the acrylic acid would be completely removed, the removal of 1 mg/l nitrate by A. facilis B or P. nautica, about 0.64-0.74 mg/l acrylonitrile or 0.87-1 mg/l acrylic acid was needed. Because strains A. facilis B and P. nautica could utilize acrylonitrile for denitrification, they are expected to play an important role in the treatment of acrylonitrile in the wastewater treatment plant (denitrification and nitrification processes) and lab-scale granular activated carbon-fluidized bed.     

In-situ bioremediation of amine- and glycol-contaminated soils using low-intervention methods

Biological plugs are an innovative, low-intervention, in-situ bioremediation methodology for both saturated and unsaturated contaminated soils. They are modular in-ground immobilized microbe bioreactors designed to rapidly increase the oxidation of organic contaminants by placing an adapted consortia of microorganisms in close proximity to the contaminants of concern. The approach is versatile, in that contaminants can be remediated in-situ without the removal of existing structures as well as being able to efficiently and economically treat contaminants over a large area. Amine- and glycol-contaminated soils at gas sweetening plants, represent a significant problem in magnitude, prevalence, and risk along pipelines stretching through Canada's western provinces. A field pilot study was conducted at an isolated former gas sweetening plant in northwestern Alberta. Monoethyamine (MEA) and several glycols were successfully remediated in situ in a 138-day time frame. Soil toxicity was significantly reduced. The engineering challenges and associated economics of remediating such isolated sites are also presented.     

Tillage and field scale controls on greenhouse gas emissions

There is a lack of understanding of how associations among soil properties and management-induced changes control the variability of greenhouse gas (GHG) emissions from soil. We performed a laboratory investigation to quantify relationships between GHG emissions and soil indicators in an irrigated agricultural field under standard tillage (ST) and a field recently converted (2 yr) to no-tillage (NT). Soil cores (15-cm depth) were incubated at 25 degrees C at field moisture content and 75% water holding capacity. Principal component analysis (PCA) identified that most of the variation of the measured soil properties was related to differences in soil C and N and soil water conditions under ST, but soil texture and bulk density under NT. This trend became more apparent after irrigation. However, principal component regression (PCR) suggested that soil physical properties or total C and N were less important in controlling GHG emissions across tillage systems. The CO2 flux was more strongly determined by microbial biomass under ST and inorganic N content under NT than soil physical properties. Similarly, N2O and CH4 fluxes were predominantly controlled by NO3- content and labile C and N availability in both ST and NT soils at field moisture content, and NH4+ content after irrigation. Our study indicates that the field-scale variability of GHG emissions is controlled primarily by biochemical parameters rather than physical parameters. Differences in the availability and type of C and N sources for microbial activity as affected by tillage and irrigation develop different levels and combinations of field-scale controls on GHG emissions.     

Carbonaceous species in fine particles at the background sites in Korea between 1994 and 1999

Organic carbon (OC) and elemental carbon (EC) in fine particles (PM_2.5) at two background sites, Kosan and Kangwha in Korea were measured during intensive field studies between 1994 and 1999. Fine particles were collected on pre-fired quartz filters in a low-volume sampler and analyzed using the selective thermal oxidation method with MnO₂ catalyst. The OC and EC concentrations at Kosan located at western tip of Cheju Island in southern Korea are lower than those at Kangwha located at western coastal area in mid-Korean peninsula. Still, the OC concentrations at Kosan are generally higher than those at other background areas in Japan and USA. The EC concentrations at Kosan are lower than or comparable to those at other background areas. The total carbon (TC, sum of OC and EC) to EC ratio values at both sites were higher than those at other background areas in Japan and USA. At Kosan, the OC and EC concentrations when air parcels were from southern China were higher than those when air parcels were coming from northern China. However, at Kangwha, the differences were statistically not clear since most air parcels were from northern China. Except when air parcels were from the North Pacific during summer, the OC and EC concentrations are well correlated indicating that both OC and EC share the same emission/transport characteristics. From the gaseous hydrocarbon data and the OC and EC relationship, it was found that during summer local biogenic emissions of OC might be significant at Kosan.     

Urinary levels of phthalate metabolites and associations with demographic characteristics in Korean adults

The objective of this study is to assess human exposure to phthalates and its associations with demographic characteristics of the subjects in the Korean National Human Biomonitoring Survey. The subjects aged between 18 and 69 were selected through nationwide stratified sampling. A total of 1874 urine samples were collected and stored at ?20 °C until measurement for ten selected metabolites of phthalates (MnBP, MiBP, MBzP, MCHP, MnOP, MEHP, MEOHP, MEHHP, MiNP, and MiDP) using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The difference in the level of urinary phthalate metabolites by the characteristics of the subjects was tested for statistical significance using SAS Surveyreg procedure. The coefficients and standard errors from multiple linear regressions were exponentiated to estimate the adjusted proportional change (APC) and 95% CIs compared with a referent level. The proportion of data above LOQ was less than 20% for MCHP, MnOP, MiNP, and MiDP. Geometric means of creatinine-adjusted concentrations (unit: μg/g creatinine) of six other phthalate metabolites among Korean adults were 41.7 (95% CI 39.6–43.9) for MnBP, 17.1 (95% CI 16.1–18.1) for MiBP, 15.7 (95% CI 14.4–17.1) for MBzP, 8.65 (95% CI 8.10–9.22) for MEHP, 17.5 (95% CI 16.8–18.3) for MEOHP, and 38.1 (95% CI 36.2–40.2) for MEHHP. Urinary level of phthalates tended to be higher among subjects with older age, females, and those with vigorous daily physical activity and tended to be lower among drinkers and those with higher income. Our results suggest that the level of phthalate exposure is significant among Korean adults and thus warrants further studies to identify major source and route of exposure to phthalates.     

Optimizing the specific surface area of fly ash-based sorbents for flue gas desulfurization

High performance sorbents for flue gas desulfurization can be synthesized by hydration of coal fly ash, calcium sulfate, and calcium oxide. In general, higher desulfurization activity correlates with higher sorbent surface area. Consequently, a major aim in sorbent synthesis is to maximize the sorbent surface area by optimizing the hydration conditions. This work presents an integrated modeling and optimization approach to sorbent synthesis based on statistical experimental design and two artificial intelligence techniques: neural network and genetic algorithm. In the first step of the approach, the main and interactive effects of three hydration variables on sorbent surface area were evaluated using a full factorial design. The hydration variables of interest to this study were hydration time, amount of coal fly ash, and amount of calcium sulfate and the levels investigated were 4-32 h, 5-15 g, and 0-12 g, respectively. In the second step, a neural network was used to model the relationship between the three hydration variables and the sorbent surface area. A genetic algorithm was used in the last step to optimize the input space of the resulting neural network model. According to this integrated modeling and optimization approach, an optimum sorbent surface area of 62.2m(2)g(-1) could be obtained by mixing 13.1g of coal fly ash and 5.5 g of calcium sulfate in a hydration process containing 100ml of water and 5 g of calcium oxide for a fixed hydration time of 10 h.     

Hygroscopic organic aerosols during BRAVO?

The hygroscopic properties of the organic fraction of aerosols are poorly understood. The ability of organic aerosols to absorb water as a function of relative humidity (RH) was examined using data collected during the 1999 Big Bend Regional Aerosol and Visibility Observational Study (BRAVO). (On average, organics accounted for 22% of fine particulate matter with an aerodynamic diameter less than 2.5 microm (PM2.5) mass). Hourly RH exceeded 80% only 3.5% of the time and averaged 44%. BRAVO aerosol chemical composition and dry particle size distributions were used to estimate PM2.5 light scattering (Bsp) at low and high ambient RH. Liquid water growth associated with inorganic species was sufficient to account for measured Bsp for RH between 70 and 95%.     

Association between prenatal exposure to phthalates and the health of newborns

Phthalates are developmental and reproductive toxicants for the fetus in pregnant rodents, and the ability of phthalates to penetrate the placenta have been reported. The aims of this study were to evaluate the association between maternal urine excretion, the exposure of fetus to phthalates in amniotic fluid, and the health of newborns. Amniotic fluid and urine samples from pregnant women were collected to measure five phthalate monoesters using liquid chromatography/tandem mass spectrometry (LC/MS-MS) and the newborns' birth weight, gestational age, and anogenital distance (AGD) were collected. The median levels of three phthalate monoesters in urine and amniotic fluid were 78.4 and 85.2 ng/mL monobutyl phthalate (MBP); 24.9 and 22.8 ng/mL mono-(2-ethylhexyl) phthalate (MEHP); 19.8 and Not Detected monoethyl phthalate (MEP). We found a significant positive correlation only between creatinine adjusted urinary MBP and amniotic fluid MBP (R(2)=0.156, p<0.05) in all infants and, only in female infants, a significantly negative correlation between amniotic fluid MBP, AGD (R=-0.31, p<0.06), and the anogenital index adjusted by birth weight (AGI-W) (R=-0.32, p<0.05). Although the influence of prenatal di-n-butyl phthalate (DBP) exposure on the endocrinology and physiology of the fetus is still a puzzle, our data clearly show that in utero exposure to phthalates in general has anti-androgenic effects on the fetus.     

The impacts of the waterfront development in Iskandar Malaysia

The increasing number of waterfront projects shows that the concept of waterfront development has contributed to the advancement of the Malaysian construction industry. This study seeks to assess the impacts of the implementation of waterfront development in Iskandar Malaysia eliciting the perceived relative importance of these impacts. A comprehensive literature review has been conducted to collate the potential impacts of the waterfront development. A total of 363 sets of questionnaires were distributed to the contractors and developers registered under G7 category of the Construction Industry Development Board in Malaysia. Results show that the most significant influence of the waterfront development is related to economic benefits, while environmental impacts are not considered as a priority for this category of stakeholders. In addition, this study also indicates that the implementation of the waterfront projects has generated numerous job opportunities within the developed region. Moreover, exchanging knowledge in the planning and managing of the waterfront development is imperative to the development of the waterfront projects. Nevertheless, the shortcomings of these developments, such as the negative environmental impact on natural beaches and the coastline (i.e. pollution) as well as human-related issues (i.e. excessive human settlement), should not be taken lightly. This research confirms that the reclamation of land for waterfront development is closely correlated with the destruction of these natural structures.