Analyses of PAHs (polycyclic aromatic hydrocarbons) and mutagenicity in raw and chlorinated water

Both raw water and chlorinated drinking water samples were collected from and the Liu‐Du water treatment plant in northern Taiwan from October 1990 to April 1992. The polycyclic aromatic hydrocarbons (PAHs) and mutagenicity in these water samples were analyzed by GC/MS and Ames test. The Mutagenicity/DMSO (Dimethyl Sulfoxide) ratio in S. typhimurium TA98 and TA100 with or without S9 mixture increased, even higher than 2, following the sequence of unit process. It was observed that the mutagenicity with TA98 (S9+) was highly related to most of PAHs in the raw water; while the mutagenicity with TA98 (S9+) was only correlated with DbA and BghiPr in the treated water. It could be expected that the mutagenicity level was controlled by other predominant components after the raw water was treated, for example, the chlorination process.     

Relationship between chlorine consumption and chlorination by-products formation for model compounds

The objective of this research is to investigate the relationship between chlorine decay and the formations of disinfection by-products (DBP), including trichloromethane (TCM) and chloroacetic acid (CAA) in the presence of four model compounds, i.e., resorcinol, phloroglucinol, p-hydroxybenzoic acid, and m-hydroxybenzoic acid. The chlorine degradation in model compounds with OH and/or COOH functional groups were rapid after chlorination. The TCM yields of carboxylic group substituted compounds (3-hydroxybenzoic acid [3-HBA], 4-hydroxybenzoic acid [4-HBA]) were found to be lower than that of the m-dihydroxy substituted compounds. Phloroglucinol, with one more OH substitution group than resorcinol, tends to form significant amounts of CAA after chlorination. However, it was observed that with the COOH substitution of 3-HBA and 4-HBA tend to exhibit more CAA formation potential than resorcinol. The developed parallel second and first-order reaction model for chlorine demand has been successfully utilized for TCM, CAA and DBP formation modeling. A high correlation between CAA and TCM was observed for the model compounds.     

Comparison of leaching characteristics of heavy metals in APC residue from an MSW incinerator using various extraction methods

This study investigates four extraction methods (water extraction, toxicity characteristics leaching procedure (TCLP), modified TCLP with pH control, and sequential chemical extraction (SCE)), each representing different liquid-to-solid (L/S) ratios, pH controls, and types of leachant, and their effects on the leaching concentration of heavy metals in municipal solid waste (MSW) incinerator air pollution control (APC) residue. The results indicated that for extraction with distilled water, the heavy metal leaching concentration (mg/l) decreased with L/S ratio, but the amount of heavy metal released (AHMR), defined as the leached amount of heavy metals to the weight of the tested sample (mg/kg), increased with an increase in L/S ratio, in the range of 2-100. The results also showed that both the leaching concentration and the amount of released metals were strongly pH-dependent in the TCLP and modified TCLP tests. In the case of pHs lower than 6.5, the leaching concentrations of Cd, Pb, Cu, Zn, and Cr decreased with an increase in pH. As pH increased higher than 6.5, Cr and Zn were almost insoluble. Meanwhile, Cd and Cu also showed a similar trend but at pHs of 8.5 and 7.5, respectively. Due to the nature of amphoteric elements, in the case of pHs higher than 7, the Pb leaching concentration increased with increasing pH. In modified TCLP tests with the pH value controlled at the same level as in the SCE test, the heavy metal speciation approached the extractable carbonate bound fraction by the SCE. Both amounts of targeted metals leached from the SCE and modified TCLP tests were much higher than those for the regular TCLP and water extraction tests.     

Particulates and Metallic Elements Monitoring at Two Sampling Sites (Harbor,Airport) in Taiwan

This study characterized the dry deposition flux and dry deposition velocity (Vd) of metallic elements attached on particulate matter. Specifically, large particles (>10 μm), coarse particles (10 μm～2.5 μm), and fine particles (<2.5 μm) were studied at the Gong Ming Junior High School (Taichung Airport) and Taichung Harbor sampling sites in central Taiwan. Ambient air samples were collected to determine total suspended particulate matter (TSP), dry deposition plate (DDP), Vd, coarse particulate matter (PM_2.5–10) and fine particulate matter (PM_2.5), and metallic elements concentrations at the Airport and Taichung Harbor sites between June 17, 2013, and November 14, 2013. The results revealed that the average TSP, DDP, Vd, PM_2.5–10, and PM_2.5 particulate at the Airport were 54.55 (μg/m³), 902.25 (μg/m²-min), 17.11 (m/sec), 0.003 (μg/m³), and 0.010 (μg/m³), respectively; while these values at Taichung Harbor were 63.66 (μg/m³), 539.69 (μg/m²-min), 9.94 (m/sec), 0.003 (μg/m³), and 0.014 (μg/m³), respectively. In addition, the results showed that the average Cu and Pb concentrations were higher than Cr, Ni, and Cd for both the airport and harbor sampling sites. Furthermore, Cr, N, Cu, Cd, and Pb had the highest average concentrations versus those reported for other study areas, with one exception: The results obtained in Kacanik, Kosovo, during 2005. The average metallic elements concentrations order was Cu > Pb > Cr > Ni > Cd.     

Adsorption Characteristics of Benzene on Biosolid Adsorbent and Commercial Activated Carbons

Abstract

This study selected biosolids from a petrochemical waste-water treatment plant as the raw material. The sludge was immersed in 0.5-5 M of zinc chloride (ZnCl₂) solutions and pyrolyzed at different temperatures and times. Results indicated that the 1-M ZnCl₂-immersed biosolids pyrolyzed at 500 °C for 30 min could be reused and were optimal biosolid adsorbents for benzene adsorption. Pore volume distribution analysis indicated that the mesopore contributed more than the macropore and micropore in the biosolid adsorbent. The benzene adsorption capacity of the biosolid adsorbent was 65 and 55% of the G206 (granular-activated carbon) and BPL (coal-based activated carbon; Calgon, Carbon Corp.) activated carbons, respectively. Data from the adsorption and desorption cycles indicated that the benzene adsorption capacity of the biosolid adsorbent was insignificantly reduced compared with the first-run capacity of the adsorbent; therefore, the biosolid adsorbent could be reused as a commercial adsorbent, although its production cost is high.     

Biodegradation of nonylphenol in soil

We investigated the effects of various factors (brij 30, brij 35, yeast extract, hydrogen peroxide and compost) on the aerobic degradation of nonylphenol (NP) in soil and characterized the structure of the microbial community in that soil. Residues of NP were measured using gas chromatography-mass spectrometry (GC-MS) and a change of microbial communities was demonstrated using denaturing gradient gel electrophoresis (DGGE). The results showed that Taichung sandy clay loam had higher NP degradation rate than Kaoshiung silty clay. The addition of compost, yeast extract (0.5 mg/l), brij 30 (55 microM), or brij 35 (91 microM) enhanced NP degradation, while the addition of hydrogen peroxide (1.0 mg/l) inhibited its degradation. We also found that the addition of various substrates changed the microbial community in the soils. Cytophaga sp. and Ochrobactrum sp. were constantly dominant bacteria under various conditions in the soil.     

Determination of volatile organic profiles and photochemical potentials from chemical manufacture process vents

The main objective of this study was to monitor the volatile organic compounds (VOCs) in the stack gas released from organic chemical industrial plants to determine emission factors. Samples from 52 stacks, with or without air pollution control devices (APCDs), from seven industrial processes were taken and VOCs measured using U.S. Environmental Protection Agency (EPA) Method 18. These 7 processes, including 26 plants, were the manufacturers of acrylonitrile-butadiene-styrene (ABS), polyvinyl chloride (PVC), polystyrene (PS), acrylic resin (ACR), vinyl chloride (VC), para-terephthalic acid (PTA), and synthetic fiber (SYF). The results clearly indicate significant variations of emission factors among the various industrial processes, particularly emission factors for those without APCDs. As expected, those with APCDs yield much less emission factors. Regardless of those with or without APCDs, the order of manufacturing processes with regard to VOC emission factors is SYF > ABS > PS >ACR > PTA > PVC > VC. The emission factors for some processes also differ from those in EPA-42 data file. The VOC profiles further indicate that some VOCs are not listed in the U.S. VOC/Particulate Matter Speciation Data System (SPECIATE). The potential O3 formation is determined from the total amount of VOC emitted for each of seven processes. The resultant O3 yield varied from 0.22 (ACR) to 2.33 g O3 g(-1) VOC (PTA). The significance of this O3 yield is discussed.     

Changes in the grassland-forest boundary at Ta-Ta-Chia long term ecological research (LTER) site detected by stable isotope ratios of soil organic matter

The carbon isotope analysis [delta13C values] of organic samples can be a useful research in ecological studies because delta13C values are indicative of the plant source. This study investigated the changes in plant communities along the grassland-forest boundary in the alpine forest at Ta-Ta-Chia long term ecological research (LTER) site in central Taiwan using carbon isotope data. The aim of this study was focused on the forest fire affected the change of vegetation community. Four pedons from grassland dominated by Miscanthus transmorrisonensis (pedons 1 and 2), transition zone by Tsuga and Yushania nittakeyamensis (pedon 3), and forest zone by Tsuga and nittakeyamensis (pedon 4) were examined. Soil organic matter (SOM) delta13C values in the upper soil horizon were similar to delta13C values of the overlaying vegetation types. This indicates that the boundary between these plant communities remained the same in the past decades. The delta13C values of the grassland SOM ranged from -19.4 per thousand to -24.1 per thousand, showing decrease with soil depth. This suggests that C4 plants (transmorrisonensis) have replaced C3 plants of Tsuga and nittakeyamensis. The delta13C values of the Tsuga forest area (pedon 4) range from -27.0 per thousand to -23.5 per thousand and showed only slight change with soil depth, implying that C3 plants have remained the major species in the forest.     

Particulate composition characteristics under different ambient air quality conditions

Particulate compositions including elemental carbon (EC), organic carbon (OC), water-soluble ionic species, and elemental compositions were investigated during the period from 2004 to 2006 in southern Taiwan. The correlation between the pollutant standard index (PSI) of ambient air quality and the various particle compositions was also addressed in this study. PSI revealed a correlation with fine (r = 0.74) and coarse (r = 0.80) particulate matter (PM). PSI manifested a significant correlation with the amount of analyzed ionic species (r approximately 0.80) in coarse and fine particles and a moderate correlation with carbon content (r = 0.63) in fine particles; however, it showed no correlation with elemental content. Although the ambient air quality ranged from good to moderate, the ionic species including chloride (Cl-), nitrate (NO3-), sulfate (SO4(2-)), sodium (Na+), ammonium (NH4+), magnesium (Mg2+), and calcium (Ca2+) increased significantly (1.5-3.7 times for Daliao and 1.8-6.9 times for Tzouying) in coarse PM. For fine particles, NO3-, SO4(2-), NH4+, and potassium (K+) also increased significantly (1.3-2.4 times for Daliao and 2.8-9.6 times for Tzouying) when the air quality went from good to moderate. For meteorological parameters, temperature evidenced a slightly negative correlation with PM concentration and PSI value, which implied a high PM concentration in the low-temperature condition. This reflects the high frequency of PM episodes in winter and spring in southern Taiwan. In addition, the mixing height increase from 980 to 1450 m corresponds to the air quality condition changing from unhealthy to good.     

Integrating total oxidizable precursor assay data to evaluate fate and transport of PFASs

Fate and transport of per‐ and polyfluoroalkyl substances (PFASs) are complex and are not well understood. Among this class of emerging contaminants, perfluoroalkyl acids (PFAAs) comprising perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFSAs) are being studied more frequently than polyfluorinated compounds. PFAAs are persistent in the environment, recalcitrant to biological degradation, and, therefore, widespread. Previous studies have indicated that some PFASs bioaccumulate. The fate and transport of PFAAs can be complicated by the presence of PFAA precursors. The PFAA precursors are defined in this article as those fluorinated chemicals that can be potentially transformed abiotically or biotically into terminal PFCA or PFSA products. Due to potential biotransformation in the environment, PFAA precursors can influence the temporal and lateral distribution of PFAAs in the environment. Presently, only a very small number of PFAA precursors can be quantitatively analyzed by commercial laboratories. For instance, N‐ethyl perfluorooctanesulfonamidoacetic acid and N‐methyl perfluorooctanesulfonamidoacetic acid are the only two precursors included in the most commonly applied PFAS analytical method, U.S. Environmental Protection Agency Method 537. The current commercial laboratory methodologies primarily quantify between 14 and 31 PFASs. As an alternative, a total oxidizable precursor assay (TOPA) was developed to quantify the measurable PFSA and PFCA concentrations after aggressive oxidation converting PFAA precursors abiotically into PFCAs. The difference between PFAA concentrations before and after oxidation can be used to estimate the amount of oxidizable PFAA precursors in the sample. This is one of the first articles that utilized TOPA data to help interpret PFAS fate and transport in the environment.