Biodegradation of crystal violet by a Shewanella sp. NTOU1

A bacterial isolate, strain NTOU1, originally isolated from the cooling system in an oil refinery could decolorize and detoxify crystal violet under anaerobic conditions. The strain was characterized and identified as a member of Shewanella decolorationis based on Gram staining, morphology characters, biochemical tests, the 16S rRNA gene and the gyrase subunit beta gene (gyrB). The optimum pH value and temperature for decolorization of crystal violet by this strain under anaerobic conditions were pH 8-9 and 30-40 degrees C, respectively. Formate (20 mM) was the best electron donor. Addition of ferric citrate did not inhibit decolorization of crystal violet, the addition of thiosulfate, ferric oxide, or manganese oxide slightly decreased decolorization, while addition of nitrite (20 mM) inhibited the decolorization of crystal violet. By supplementing the medium with formate and ferric citrate and cultivating it under optimum pH and temperature, this strain could remove crystal violet, at a concentration of 1500 mg l(-1), at the rate of 298 mg l(-1) h(-1) (during decolorization the OD(600) of the cell culture increased from approximately 0.6 to approximately 1.2). GC/MS analysis of the degradation products of crystal violet detected the presence of N,N'-bis(dimethylamino) benzophenone (Michler's Ketone), [N,N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N,N-dimethylaminobenzaldehyde, N,N-dimethylaminophenol, and 4-methylaminophenol. These results suggest that crystal violet was biotransformed into N,N-dimethylaminophenol and Michler's Ketone prior to further degradation of these intermediates. This paper proposes a probable pathway for the degradation of crystal violet by this Shewanella sp. Cytotoxicity and antimicrobial tests showed that the process of decolorization also detoxify crystal violet.     

An integrated approach for identification of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) pollutant sources based on human blood contents

Background, aim, and scope  

This study developed an integrated approach to identify pollutant sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) of workers based on their blood contents.     

The effects of FeCl3 on the distribution of the heavy metals Cd, Cu, Cr, and Zn in a simulated multimetal incineration system

Recognizing that waste-derived chlorine can enhance heavy metal emissions by forming volatile metallic chlorides during municipal solid waste (MSW) combustion, and that in Taiwan, FeCl3-containing sewage sludge may either be landfilled or coincinerated with other MSW, this study thus investigated the effects of FeCl3 on the speciation and partitioning of heavy metals in a multimetal incineration system by using a tubular furnace and FeCl3-spiked simulated wastes. The molar ratio of chlorine content to heavy metal content (referred to as the Cl/ M ratio), ranging from 3 to 200, was used as a parameter to evaluate the effects of chlorine on the movement of heavy metals between the incinerator discharges. Results indicate that speciation and partitioning were related to the affinity between the chlorine and the heavy metals and between chlorine and hydrogen in the combustion system. The effectiveness of increasing the Cl/M ratio to the formation potential of metallic chlorides and on the shift of heavy metals from the bottom ash to the fly ash and/or the flue gases was found to have in increasing order as follows: Zn>Cu>Cr, a phenomenon basically reflecting the volatility of the heavy metals and their chlorides formed during combustion.     

Simulation modeling for nitrogen removal and experimental estimation of mass fractions of microbial groups in single-sludge system

Nitrification-denitrification in a single-sludge nitrogen removal system (SSNRS; with a sufficient carbon source for denitrification) was performed. With an increase in the mixed liquor recycle ratio (R(m)) from 1 to 2, the total nitrogen (TN) removal efficiency at a lower volumetric loading rate (VLR=0.21 NH(4)(+)-N m(-3) d(-1)) increased, but the TN removal efficiency at a higher VLR (0.35 kg NH(4)(+)-N m(-3) d(-1)) decreased. A kinetic model that accounts for the mass fractions of Nitrosomonas, Nitrobacter, nitrate reducer and nitrite reducer (f(n1), f(n2), f(dn1), and f(dn2)) in the SSNRS and an experimental approach for the estimation of the mass fractions of nitrogen-related microbial groups are also proposed. The estimated f(dn1) plus f(dn2) (0.65-0.83) was significantly larger than the f(n1) plus f(n2) (0.28-0.32); the f(n1) (0.21-0.26) was larger than the f(n2) (0.05-0.07); and the f(dn1) (0.32-0.45) varied slightly with the f(dn2) (0.33-0.38). At the lower VLR, the f(dn1) plus f(dn2) increased with increasing R(m); however at the higher VLR, the f(dn1) plus f(dn2) did not increase with increasing R(m). By using the kinetic model, the calculated residual NH(4)(+)-N and NO(2)(-)-N in the anoxic reactor and NO(2)(-)-N and NO(3)(-)-N in the aerobic reactor were in fairly good agreement with the experimental data; the calculated NO(3)(-)-N in the anoxic reactor was over-estimated and the calculated NH(4)(+)-N in the aerobic reactor was under-estimated.     

A review on environmental distributions and risk management of phenols pertaining to the endocrine disrupting chemicals in Taiwan

Some phenols, including pentachlorophenol, dichlorophenol, alkylphenols (nonylphenol & octylphenol) and bisphenol-A, have been identified as endocrine disrupting chemicals (EDCs). These phenolic EDCs are extensively used in a wide range of household products, thus posing potential health risks for humans exposed to them. From the viewpoints of ecotoxicology, human health and regulations, it is urgent to restrict the emissions and releases of these estrogenic chemicals from the industrial processes and commercial products. This review article first focused on the physicochemical properties of phenolic EDCs and their industrial/commercial uses. Furthermore, their environmental distributions and regulatory frameworks for integrated risk management of these chemicals in Taiwan were conducted as a case study. Emphasis was thus put on the cross-ministerial joint venture (i.e., environment, health, agriculture, labor, and industry authorities), and the government policy on the risk management of EDCs. Finally, some recommendations for pollution prevention and toxicity reduction of phenolic EDCs were also addressed and analyzed to progress towards a sustainable society in Taiwan.     

The effects of nanomaterials on microstructures of sludge ash cement paste

To broaden the beneficial reuse of sewage sludge, small amounts of nanomaterial were considered as additives to evaluate influences of nanomaterials on microstructures of sludge cement paste. Paste specimens were manufactured using different mix designs and cured for various ages. Tests such as scanning electron microscope, X-ray diffraction, transmission electron microscope, and mercury intrusion porosimetry were then performed. Results obtained indicated that the quantities of crystallization in hydrates rose with the increased amounts of nanomaterial added. Moreover, nanomaterial additives could make crystallizations denser, pore sizes smaller, and the number of pores decreased. Consequently, the strength of sludge cement paste became better as more amounts of nanomaterial were added.     

The Impacts of Water Conservation Strategies on Water Use: Four Case Studies1

Tsai, Yushiou, Sara Cohen, and Richard M. Vogel, 2011. The Impacts of Water Conservation Strategies on Water Use: Four Case Studies. Journal of the American Water Resources Association (JAWRA) 47(4):687‐701. DOI: 10.1111/j.1752‐1688.2011.00534.x Abstract: We assessed impacts on water use achieved by implementation of controlled experiments relating to four water conservation strategies in four towns within the Ipswich watershed in Massachusetts. The strategies included (1) installation of weather‐sensitive irrigation controller switches (WSICS) in residences and municipal athletic fields; (2) installation of rainwater harvesting systems in residences; (3) two outreach programs: (a) free home indoor water use audits and water fixture retrofit kits and (b) rebates for low‐water‐demand toilets and washing machines; and (4) soil amendments to improve soil moisture retention at a municipal athletic field. The goals of this study are to summarize the effectiveness of the four water conservation strategies and to introduce nonparametric statistical methods for evaluating the effectiveness of these conservation strategies in reducing water use. It was found that (1) the municipal WSICS significantly reduced water use; (2) residences with high irrigation demand were more likely than low water users to experience a substantial demand decrease when equipped with the WSICS; (3) rainwater harvesting provided substantial rainwater use, but these volumes were small relative to total domestic water use and relative to the natural fluctuations in domestic water use; (4) both the audits/retrofit and rebate programs resulted in significant water savings; and (5) a modeling approach showed potential water savings from soil amendments in ball fields.     

Environmental implications of perfluorotributylamine—a potent greenhouse gas

Perfluorotributylamine (PFTBA), a newly discovered greenhouse gas with the highest radiative efficiency, may have been released into the environment from a variety of industrial and medical uses in small amounts, leading to the potential contribution to the global warming addressed in the United Nations Framework Convention on Climate Change Kyoto Protocol. The aims of this article are to review the physicochemical properties and commercial/potential uses of PFTBA reported in the current available literature and also discuss its environmental implications based on its molecular structure. Results showed that PFTBA had extremely low solubility in water and relatively high vaporization from the water bodies, suggesting that this long-lived greenhouse gas will sink into the atmosphere. This paper also addressed the possible loss pathways through reactions with highly reactive ions in the upper atmosphere and toxic decomposition products (e.g., hydrogen fluoride, fluorine, and carbonyl fluoride) emitted when heated at high temperature. In this regard, there is a need for PFTBA emission reduction strategies due to its increasing usage in many professional applications and its potential contribution to anthropogenic climate forcing in the near future.     

Agenesis of the corpus callosum: What to tell expecting parents?

Agenesis of the corpus callosum (ACC) is one of the most common brain malformations, with an incidence estimated to range from 0.5 to 70 in 10,000 among the general population. Prenatal diagnosis is made via ultrasound; however, fetal MRI is useful to confirm or exclude the presence of associated cerebral abnormalities–mostly cortical malformations–that may affect postnatal prognosis. When no additional central nervous system (CNS) or extra CNS anomalies are identified and no genetic cause is found, an isolated ACC is diagnosed. Overall, in cases of ACC, an underlying genetic cause can be identified in up to 12.5% with chromosomal microarray (CMA) and up to 47% with whole exome sequencing (WES). In cases where ACC is the only anomaly detected, the yield of WES is 30%. Postnatal outcomes are variable and depend on whether the condition is isolated or not. In truly isolated ACC, outcomes range from normal in 65% of cases through mild to severe neurodevelopmental impairments in 35% of cases. An interdisciplinary team of medical experts is key in guiding parents toward informed decision-making in pregnancies complicated by ACC. Considering current and expected advancements in genetic testing and imaging technologies in upcoming years, we herein summarize current recommendations for the management and prenatal counseling of expecting parents of fetuses with ACC. Our review pertains primarily to expecting parents of fetuses with complete ACC.     

Air pollution associated with cognitive decline by the mediating effects of sleep cycle disruption and changes in brain structure in adults

Environmental Science and Pollution Research - The effects of air pollution on sleep and dementia remain unclear. The objective of this study was to investigate the effects of air pollution on...