Pilot on-site tests to evaluate the permeability of infiltration gutters.

This study assessed the performance and developed a simple approach for estimating infiltration capacity of two infiltration gutters by using on-site tests. Permeable-brick and redbrick infiltration gutters were constructed on-site. Water infiltrated from the surfaces of two vertical sides (NFS-2S), bottom (NFS-B), and three faces (NFS-3S) of two gutters were measured under nonflowing and steady-state conditions. Tests results from NFS-2S and NFS-3S indicate that the permeability and water depth for both gutters are linearly dependent on each other. Experimental results also indicate that, when the bottom of the gutter is clogged, the permeable-brick gutter still retains approximately 93 and 79% for redbrick gutter of their infiltration capacity for NFS-3S. On the whole, permeable-brick gutter has an advantage over redbrick gutter in stormwater infiltration. Based on these results, the permeability for different water depths and widths of these two gutters can be obtained.     

Tissue distribution of absorbed humic acids

Distribution of humic acids (HA) in rats was studied using radioiodinated HA injected intraperitoneally. Distribution of ¹²⁵I was also studied for comparison. The distribution pattern of HA differed greatly from that of ¹²⁵I. Except in the thyroid and skin, ¹²⁵I was excreted from the body within 24 hours, whereas a large proportion of HA remained in the liver, kidney, skin, thyroid, bone and muscle. The difference in the distribution pattern and organ/serum radioactivity ratio suggests different kinetics for ¹²⁵I and ¹²⁵I-HA. The distribution pattern of HA correlated very well with the increased prevalences of organ diseases in the blackfoot disease endemic area, as reflected in epidemiologic studies. It is hypothesised that HA-metal complexes are possible etiological factors of diseases such as goitre, hepatoma, bladder cancer, vascular disease and diabetes mellitus, and that free radicals are the common causative factor.     

Cytotoxicity of municipal solid waste incinerator ash wastes toward mammalian kidney cell lines

In this study, three municipal solid waste incinerator (MSWI) ash wastes-bottom ash, scrubber residue, and baghouse ash-were extracted using a toxicity characteristic leaching procedure (TCLP) extractant. These so-called final TCLP extracts were applied to African green monkey kidney cells (Vero), baby hamster kidney cells (BHK-21), and pig kidney cells (PK-15), multi-well absorption reader analysis was performed to test how the cytotoxicity of the incineration ashes would affect the digestive systems of animals. Ion-coupled plasma analyses indicated that the baghouse ash extract possessed the highest pH and heavy metal concentration, its cytotoxicity was also the highest. In contrast, the bottom ash and the scrubber residue exhibited very low cytotoxicities. The cytotoxicities of mixtures of baghouse ash and scrubber residue toward the three tested cell lines increased as the relative ratio of the baghouse ash increased, especially for the Vero cells. The slight cytotoxicity of the scrubber residue arose mainly from the presence of Cr species, whereas the high cytotoxicity of the baghouse ash resulted from its high content of heavy metals and alkali ions. In addition, it appears that the dissolved total organic carbon content of these ash wastes can reduce the cytotoxicity of ash wastes that collect in animal cells.     

Determinations and residual characteristics of triclosan in household food detergents of Taiwan

Triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) is a widely used antibacterial agent. However, it was concerned recently that triclosan might act as an antibiotic and will cause resistant bacterial strains. Furthermore, possible formation of toxic chloroform was also reported when the triclosan contained in household dishwashing soaps reacted with the chlorinated water. To assess the associate risks from possible exposures, concentrations of triclosan in household food detergents of Taiwan were determined in this study. High performance liquid chromatography (HPLC) with UV detector at 280 nm was used to analyze the triclosan in samples. Factors that might affect the residual characteristics of triclosan from detergents on dishware and fruits, including the concentrations of detergents used, the temperature and immersion time for water before the cleaning processes, the temperatures of water used for the cleaning processes, and the materials of dishware made of, were evaluated under the orthogonal experiment design by the Taguchi method. By the analysis of variance, the orders of importance of different parameters were determined. The concentrations of triclosan detected in household food detergents were found to be 1.7 x 10(-2) -5.6 x 10(-1) (triclosan/detergent, mg g(-1)). For residual characteristics, the concentration of detergents used as well as the materials of dishware were found to be the significant factors that will affect the triclosan left on the dishware. On the other hand, the concentration of triclosan in the detergents was found to be the only factor that will affect the triclosan left on fruits. The maximum dose of triclosan exposures from the use of household food detergents in Taiwan was also estimated in the study.     

Evolutions of microbial degradation pathways for parent xenobiotic and for its metabolites follow different schemes

Background and purposes

The pathways used by microorganisms for the metabolism of every xenobiotic substrate are specific. The catabolism of a xenobiotic goes through a series of intermediate steps and lower intermediates (metabolites) appear in sequence. The structure of the metabolites can be similar to the parents due to kinship. The purposes of this study were to examine if the degradation pathways that were developed for a parent xenobiotic are effective to degrade the parent??s lower metabolites, and if the reverse is true.

Materials and methods

The xenobiotic substrates, 2,4-dichlorophenoxyacetic acid (2,4-D, the parent xenobiotic) and its metabolite 2,4-dichlorophenol (2,4-DCP), were independently subjected to acclimation and degradation tests by the biomasses of mixed-culture activated sludge and a pure culture of Arthrobacter sp.

Results

Activated sludge and Arthrobacter sp. that were acclimated to 2,4-D effectively degraded 2,4-D and the lower metabolites of 2,4-D, typically 2,4-DCP. During the degradation of 2,4-D, accumulations of the lower metabolites of 2,4-D were not found. The degradation pathways acquired from acclimation to 2,4-D are effective for all the metabolites of 2,4-D. However, pathways acquired from acclimation to 2,4-DCP are not effective in the degradation of the parent 2,4-D.

Conclusions

Microorganisms acclimated to 2,4-D evolve their degradation pathways by a scheme that is different from the scheme the microorganisms employ when they are acclimated to the metabolites of 2,4-D.     

Partition and tempospatial variation of gaseous and particulate mercury at a unique mercury-contaminated remediation site

This study investigated the seasonal variation and spatial distribution of gaseous and particulate mercury at a unique mercury-contaminated remediation site located at the near-coastal region of Tainan City, Taiwan. Gaseous elemental mercury (GEM), particulate mercury (PTM), and dustfall mercury (DFM) were measured at six nearby sites from November 2009 to September 2010. A newly issued Method for Sampling and Analyzing Mercury in Air (National Institute of Environmental Analysis [NIEA] Method A304.10C) translated from U.S. Environmental Protection Agency (EPA) Method 10-5, was applied for the measurement of atmospheric mercury in this particular study. One-year field measurements showed that the seasonal averaged concentrations of GEM and PTM were in the range of 5.56-12.60 and 0.06-0.22 ng/m3, respectively, whereas the seasonal averaged deposition fluxes of DFM were in the range of 27.0-56.8 g/km2-month. The maximum concentrations of GEM and PTM were 38.95 and 0.58 ng/m3, respectively. The atmospheric mercury apportioned as 97.42-99.87% GEM and 0.13-2.58% PTM. As a whole, the concentrations of mercury species were higher in the springtime and summertime than those in the wintertime and fall. The southern winds generally brought higher mercury concentrations, whereas the northern winds brought relatively lower mercury concentrations, to the nearby fishing villages. This study revealed that the mercury-contaminated remediation site, an abandoned chlor-alkali manufacturing plant, was the major mercury emission source that caused severe atmospheric mercury contamination over the investigation region. The hot spot of mercury emissions was allocated at the southern tip of the abandoned chlor-alkali manufacturing plant. On-site continuous monitoring of GEM at the mercury-contaminated remediation site observed that GEM concentrations during the open excavation period were 2-3 times higher than those during the nonexcavation period.     

The Application of Water Quality Monitoring Data in a Reservoir Watershed Using AMOS Confirmatory Factor Analyses

This study investigates six water quality monitoring stations in the watershed of the Feitsui Reservoir. It uses nine parameters of water quality collected in an interval of two and half years for factor analyses, which was first conducted to determine four types of factors, respectively, those for organic pollution, eutrophication, seasonal influence, and sediment pollution. The analysis results effectively help to determine water quality in the watershed of the reservoir. The authors reutilize analysis of moment structures (AMOS) to acquire further results in order to confirm the goodness of fit of the previous factor analysis model. During the confirmation, we examine the hypothesized orthogonal results as well as utilize oblique rotation to explore the goodness of fit of the reflective indicators of the orthogonal rotation. As shown in the algorithm results, as long as the covariance curve is included in the four factors, no related issues are detected in the goodness of fit of reflective indicators and interior and external quality is reported with excellence. The orthogonal model, thus, stands. Additionally, when the analysis of structural equation modeling (SEM) is conducted, sample data mismatches the hypotheses of multivariate normality. Therefore, this study adopts the generalized least square (GLS) for an algorithm. Research results of this study have been submitted to the reservoir management authorities in Taiwan for the improvement of statistical application and strategic evaluation of water quality monitoring data in order to strengthen the managerial effectiveness of water quality in watersheds.     

The Impact of Typhoon Morakot on Heavy Metals of Dapeng Bay and Pollution from Neighboring Rivers

This study demonstrates that prior to Typhoon Morakot, the index of heavy metals such as Cd, Pb, and Cr was above moderate pollution levels in Dapeng Bay and the three neighboring rivers. During January 2007, the content of Zn metal in Dapeng Bay and Tungkang River was also above moderate pollution levels, while after the Typhoon Morakot event, all metals were at levels below the criteria for low pollution. This work has demonstrated that the samples collected from Dapeng Bay and the three neighboring river systems displayed individual crowd–distribution phenomena, indicating variability between the heavy metal content of sediments collected from Dapeng Bay and the three neighboring rivers. Understanding the spatial and temporal variability of heavy metal pollutants in the sediments of Dapeng Bay, along with pollution sources from three neighboring rivers, provides useful information in the fields of disaster management, habitat recovery, operative management, as well as ecotourism specification.     

The efficacy and cytotoxicity of iron oxide-carbon black composites for liquid-phase toluene oxidation by persulfate

Environmental Science and Pollution Research - This study evaluated the oxidation of toluene (TOL) by persulfate (PS) in aqueous solution in the presence of a Fe3O4-carbon black (CB) composite...