Estrogenic effects of phenolic compounds on glucose-6-phosphate dehydrogenase in MCF-7 cells and uterine glutathione peroxidase in rats

In this study, we tested phenolic compounds such as bisphenol A (BPA), 4-nonylphenol (NP), 4-octylphenol (OP) and 4-propylphenol (PP) by using glucose-6-phosphate dehydrogenase (G6PD) in estrogen sensitive human breast cancer cells (MCF-7 cells) and glutathione peroxidase (GPx) in female immature Sprague-Dawley (SD) rats. This study was designed to investigate whether phenolic compounds have estrogenic effects in these useful screening methods for endocrine disruptors. We chose 6 h as the incubation period for the G6PD assay through a preliminary experiment using 17beta-estradiol (E2). Above the concentration of 1 x 10(-8) M, BPA significantly increased the G6PD activity in a concentration-dependent manner, relative to the control. NP (over the concentration of 1 x 10(-9) M) also enhanced the G6PD activity by about 1.8 times that of the control. OP produced weaker effects on G6PD than NP, and showed a tendency to increase the G6PD activity. PP did not affect the G6PD activity. These results show that BPA and NP have the effect of enhancing G6PD activities in MCF-7 cells. In the in vivo GPx assay, both BPA and E2 significantly increased the uterus wet weights and dramatically enhanced uterine GPx activities in immature female rats in a dose-dependent manner. Treatment with NP (500 mg/kg/day) increased significantly both the uterine GPx activity and the uterus wet weights in immature female rats. OP (500 mg/kg/day) also caused a significant increase in uterine GPx activity, but had no effect on the uterus wet weights. This finding indicates that the change in uterine GPx activities could be a more sensitive parameter than that of uterus wet weights in immature rats. This study implies that phenolic compounds have a weak estrogenic effects.     

From the enclave to the city: the economic benefits of immigrant flexibility

While much attention has been paid to the entrepreneurial “base” of the ethnic economy, the enclave is primarily composed of thousands of hourly employees working in small co-ethnic or multi-ethnic immigrant firms. The US economy benefits from over 10?billion dollars in taxed income and wages from immigrants whose social security numbers do not match up with their employee tax identification numbers. Multiple mismatches and misinformation about immigrants (from an economic, cultural, and political standpoint) demonstrate the need to understand the unique potential of immigrant communities in facilitating urban growth. Koreatown in Los Angeles, an ethnic enclave economy that is also a central business district for many immigrant workers, is one emergent example of new types of flexibility around citizenship status and semi-formal jobs as they are negotiated on a daily basis in the neighbourhood. Previous studies of the ethnic enclave have maintained that there is a singular importance to the co-ethnic network (Korean to Korean, or Cuban to Cuban, for example), and yet this traditional characterisation of the ethnic enclave does not hold true in most urban ethnic enclaves, which include multiple ethnic groups working side by side. Interviews with Korean and Latino workers demonstrate the ways in which people (including undocumented individuals) contribute to the local economy, and informally communicate in neighbourhoods and cities to build a broader social and economic network outside of enclave boundaries.     

Comparison of the physical and chemical characteristics of fine road dust at different urban sites

The size distribution and chemical components of a fine fraction (<2.5 μm) of road dust collected at urban sites in Korea (Gwangju) and Mongolia (Ulaanbaatar) where distinct urban characteristics exist were measured. A clear bimodal size distribution was observed for the resuspended fine road dust at the urban sites in Korea. The first mode peaked at 100–110 nm, and the second peak was observed at 435–570 nm. Ultrafine mode (~30 nm) was found for the fine road dust at the Mongolia site, which was significantly affected by residential coal/biomass burning. The contribution of the water-soluble ions to the fine road dust was higher at the sites in Mongolia (15.8–16.8%) than at those in Korea (1.2–4.8%). Sulfate and chloride were the most dominant ionic species for the fine road dust in Mongolia. As (arsenic) was also much higher for the Mongolian road dust than the others. The sulfate, chloride, and As mainly come from coal burning activity, suggesting that coal and biomass combustion in Mongolia during the heating season should affect the size and chemical components of the fine road dust. Cu (copper) and Zn (zinc), carbonaceous particles (organic carbon [OC] and elemental carbon [EC]) increased at sites in Korea, suggesting that the fine road dust at these sites was significantly affected by the high volume of traffic (engine emission and brake/tire wear). Our results suggest that chemical profiles for road dust specific to certain sites should be applied to more accurately apportion road dust source contributing to the ambient particulate matter.

Implications: Size and chemical characteristics of fine road dust at sites having distinct urban characteristics were examined. Residential coal and biomass burning and traffic affected physiochemical properties of the fine road dust. Different road dust profiles at different sites should be needed to determine the ambient PM2.5 sources more accurately.     

Sustainable Water Resources Management in a Conflict Resolution Framework1

Abstract: A decision support system for sustainable water resources management in a water conflict resolution framework is developed to identify and evaluate a range of acceptable alternatives for the Geum River Basin in Korea and to facilitate strategies that will result in sustainable water resource management. Working with stakeholders in a “shared vision modeling” framework, sustainable management strategies are created to illustrate system tradeoffs as well as long‐term system planning. A multi‐criterion decision‐making (MCDM) approach using subjective scales is utilized to evaluate the complex water resource allocation and management tradeoffs between stakeholders and system objectives. The procedures used in this study include the development of a “shared vision model,” a simulated decision‐making support system (as a tool for sustainable water management strategies associated with water conflicts, management options, and planning criteria), and the application of MCDM techniques for evaluating alternatives provided by the model. The research results demonstrate the utility of the sustainable water resource management model in aid of MCDM techniques in facilitating flexibility during initial stages of alternative identification and evaluation in a basin suffering from severe water conflicts.     

Comparison of morphological defences in asexually and sexually reproduced eggs of Daphnia (D. galeata and D. similis) against fish kairomones

In the present study, we investigated morphological changes of hatchlings from asexually and sexually produced eggs of Daphnia galeata and D. similis against fish kairomones. In both species, hatchlings from asexual eggs showed induced traits, such as short body length, long tail spine and high relative tail spine length when influenced by fish kairomones. However, hatchlings from sexual eggs expressed high relative tail spine length regardless of kairomones presence. The results showed that the inducibility of morphological defences depends on the egg type, with inducible defences predominant in asexual eggs while fixed defences are employed by the offspring of sexual eggs in Daphnia.     

Mitigating Global Warming Potentials of Methane and Nitrous Oxide Gases from Rice Paddies under different irrigation regimes

A field experiment was conducted in Bangladesh Agricultural University Farm to investigate the mitigating effects of soil amendments such as calcium carbide, calcium silicate, phosphogypsum, and biochar with urea fertilizer on global warming potentials (GWPs) of methane (CH₄) and nitrous oxide (N₂O) gases during rice cultivation under continuous and intermittent irrigations. Among the amendments phosphogypsum and silicate fertilizer, being potential source of electron acceptors, decreased maximum level of seasonal CH₄ flux by 25–27 % and 32–38 % in continuous and intermittent irrigations, respectively. Biochar and calcium carbide amendments, acting as nitrification inhibitors, decreased N₂O emissions by 36–40 % and 26–30 % under continuous and intermittent irrigations, respectively. The total GWP of CH₄ and N₂O gases were decreased by 7–27 % and 6–34 % with calcium carbide, phosphogypsum, and silicate fertilizer amendments under continuous and intermittent irrigations, respectively. However, biochar amendments increased overall GWP of CH₄ and N₂O gases.     

Feasibility of phosphate fertilizer to immobilize cadmium in a field

To reduce effectively cadmium (Cd) phytoextractability by phosphate fertilizer in Cd contaminated soil, fused and superphosphate (FSP) was applied at the rate of 0, 33.5 (recommendation level), 167.5, and 335 kg P ha⁻¹ for radish (Raphanus sativa L.). Unlike from what we expected, soil Cd extractability and Cd concentration in radish increased with increasing FSP application in the field. To determine the effect of FSP on Cd immobilization, FSP was mixed with the selected soil at the rate of 0, 200, 400, 800, and 1600 mg P kg⁻¹ and then incubated for 8 weeks. As observed in the field study, NH₄OAc extractable Cd concentration increased slightly with FSP addition up to 400 mg P kg⁻¹ and thereafter dramatically decreased upon increasing its application rate. Soil pH and negative charge were decreased at low level of FSP application up to 400 mg P kg⁻¹, but thereafter continually increased with increasing application level. This could be indirect evidence that net soil negative charge was increased by the specific adsorption of phosphate at the high rate of FSP application over 400 mg P kg⁻¹. The labile Cd fraction (water soluble and exchangeable + acidic fraction) increased with increasing FSP application by 400 mg P kg⁻¹ and thereafter gradually decreased with corresponding increase in unlabile fraction (oxidizable and residual fraction). Based on these results, FSP might be applied with a very high rate over 800 mg P kg⁻¹ to decrease Cd extractability in the selected field. However, this level is equivalent to 1440 kg P ha⁻¹, which is about 43 times higher than the recommendation levels for radish production and resulted in a significant increase in water soluble P concentration creating a new environmental problem. Therefore, the feasibility of FSP to reduce Cd extractability in the field is very low.     

Destruction of lindane and atrazine using stabilized iron nanoparticles under aerobic and anaerobic conditions: effects of catalyst and stabilizer

Highly stable Fe-Pd bimetallic nanoparticles were prepared with 0.2% (w/w) of sodium carboxylmethylcellulose (CMC) as a stabilizer. The effectiveness of the stabilized Fe-Pd nanoparticles was studied for degradation of two chlorinated pesticides (lindane and atrazine) under aerobic and anaerobic conditions. Batch kinetic tests showed that under anaerobic condition the nanoparticles can serve as strong electron donors and completely reduce 1 mgl(-1) of lindane at an iron dose of 0.5 gl(-1) or 1mg l(-1) of atrazine with 0.05 gl(-1) iron with a trace amount (0.05-0.8% of Fe) of Pd as a catalyst. In contrast, under aerobic condition, the nanoparticles can facilitate Fenton-like reactions, which lead to oxidation of 65% of lindane under otherwise identical conditions. Under aerobic condition, the presence of CMC reduced the level of hydroxyl radicals generated from the nanoparticels by nearly 50%, and thus, inhibited the oxidation of the contaminants. While the particle stabilization greatly enhanced the anaerobic degradation, it did not appear to be beneficial under aerobic condition. The degradation rate was progressively enhanced as the Pd content increased from 0.05% to 0.8% of Fe, and the catalytic effect of Pd was more significant under anaerobic condition. Under anaerobic condition, lindane is degraded via dihaloelimination and dehydrohalogenation, whereas atrazine is by reductive dechlorination followed by subsequent reductive dealkylation. Under aerobic condition, reactive oxygen species and hydroxyl radicals from the iron nanoparticles are responsible for oxidizing the pesticides. Lindane is oxidized via dechlorination/dehydrohalogenation, whereas atrazine is destroyed through dealkylation of the alkylamino side chain.     

Sorption of nonpolar neutral organic compounds to humic acid-coated sands: contributions of organic and mineral components

The contributions of organic matter and the mineral surface to the overall sorption of six nonpolar neutral organic compounds (1,2,4-trichlorobenzene, 1,4-dichlorobenzene, chlorobenzene, m-xylene, toluene, benzene) by five humic acid (HA)-coated sands with different fractions of organic carbon (f(oc)) ranging from 0.024% to 0.154% were evaluated on the basis of measured data and four different sorption models. Sorption of all six sorbates to both uncoated and heated sands was nearly linear due to the coverage of hydrophilic mineral surface with the ordered vicinal water region. Sorption of all six sorbates to the HA-coated sands was also essentially linear, and resulted from a combination of sorption to both organic matter and the mineral surface, with the dominance of either contribution depending on the properties of the sorbents (e.g., f(oc)) and the sorbates (e.g., K(ow)). A proposed two-component model for sorption including blocking effect was appropriate for quantifying the contributions of organic matter and the mineral surface to the overall sorption. However, conventional sorption models considering the contributions of both organic matter and the mineral surface provided essentially as good agreement between predicted and measured distribution coefficients as the more complicated, two-component model for sorption that takes into account mineral surface blocking by HA.