To estimate the atmospheric exposure of the greenhouse workers to pesticides, solid phase microextraction (SPME) was used under non-equilibrium conditions. Using Fick's law of diffusion, the concentrations of pesticides in the greenhouse can be calculated using pre-determined sampling rates (SRs). Thus the sampling rates (SRs) of two modes of SPME in the lab and in the field were determined and compared. The SRs for six pesticides in the lab were 20.4-48.3 mL min-1 for the exposed fiber and 0.166-0.929 mL min-1 for the retracted fiber. In field sampling, two pesticides, dichlorvos and cyprodinil were detected with exposed SPME. SR with exposed SPME for dichlorvos in the field (32.4 mL min-1) was consistent with that in the lab (34.5 mL min-1). SR for dichlorvos in the field (32.4 mL min-1) was consistent with that in the lab (34.5 mL min-1). The trends of temporal concentration and the inhalation exposure were also obtained.

This study provides the first evidence on the influence of the semiconductor and electronics industries on perfluorinated chemicals (PFCs) contamination in receiving rivers. We have quantified ten PFCs, including perfluoroalkyl sulfonates (PFASs: PFBS, PFHxS, PFOS) and perfluoroalkyl carboxylates (PFCAs: PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA) in semiconductor, electronic, and optoelectronic industrial wastewaters and their receiving water bodies (Taiwan's Keya, Touchien, and Xiaoli rivers). PFOS was found to be the major constituent in semiconductor wastewaters (up to 0.13 mg/L). However, different PFC distributions were found in electronics plant wastewaters; PFOA was the most significant PFC, contributing on average 72% to the effluent water samples, followed by PFOS (16%) and PFDA (9%). The distribution of PFCs in the receiving rivers was greatly impacted by industrial sources. PFOS, PFOA and PFDA were predominant and prevalent in all the river samples, with PFOS detected at the highest concentrations (up to 5.4 μg/L). The semiconductor, electronics and optoelectronic industries are the primary source of PFC contamination in downstream aqueous environments.

An integrated experimental program was conducted to remove Cd, Pb and Cu from contaminated soil. The chelate agents nitrilotriacetic acid (NTA), diethylenetriamine pentaacetic acid (DTPA) and ethyleneglycol tetraacetic acid (EGTA) were used as washing solutions under different pH conditions and concentrations. Results showed that the extraction efficiency for Cd in decreasing order was NTA > EGTA > DTPA, while for Pb and Cu it was DTPA > NTA > EGTA. The use of higher chelate concentrations did not necessarily result in greater extraction efficiency. Electrokinetic remediation was applied by conditioning anolyte–catholyte pH to neutral values in order to avoid any potential alterations to the physicochemical soil properties. The removal efficiency for Cd was 65–95%, for Cu 15–60%, but for Pb was less than 20%. The phytotoxicity of the treated soil showed that the soil samples from the anode section were less phytotoxic than the untreated soil, but the phytotoxicity was increased in the samples from the cathode section. Cadmium, lead and copper were extracted from contaminated soil by integrated electrokinetic and soil washing studies.

In situ chemical oxidation is a commonly applied soil and groundwater remediation technology, but can have significant effects on soil properties, which in turn might affect fate and transport of organic contaminants. In this study, it was found that oxidation treatment resulted mainly in breakdown of soil organic matter (SOM) components. Sorption of naphthalene and phenanthrene to the original soils and the KMnO₄-treated soils was linear, indicating that hydrophobic partitioning to SOM was the predominant mechanism for sorption. Desorption from the original and treated soils was highly resistant, and was well modeled with a biphasic desorption model. Desorption of residual naphthalene after treating naphthalene-contaminated soils with different doses of KMnO4 also followed the biphasic desorption model very well. It appears that neither changes of soil properties caused by chemical oxidation nor direct chemical oxidation of contaminated soils had a noticeable effect on the nature of PAH-SOM interactions. Chemical oxidation of soils had little effect on the mechanisms controlling sorption and desorption of PAHs.

The degradation of a chiral nonylphenol isomer, 4-(1-ethyl-1,4-dimethylpentyl)phenol (NP₁₁₂), in two agricultural soils from Monheim and Dortmund, Germany has been studied. The degradation of NP₁₁₂ and the formation of a nitro-nonylphenol metabolite were determined by means of GC-MS analysis. The degradation followed bi-exponential order kinetics, with half-life of less than 5 days in both soils. The nitro-metabolite was found at different concentration levels in the two soils. The nitro-metabolite of NP₁₁₂ was more persistent than its parent compound. After 150 days about 13% of the initially applied NP₁₁₂ remained in the Monheim soil as its nitro-metabolite. Results of the E-screen assay revealed that the nitro-NP₁₁₂ has oestrogenic potency of 85% of that of NP₁₁₂. Furthermore, the results of chiral GC-MS analysis revealed that no chiral degradation of NP₁₁₂ occurred in this study. The degradation of a chiral nonylphenol isomer in agricultural soils followed bi-exponential order kinetics resulting in a more persistent nitro-metabolite.

The spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in Daya Bay, China. The total concentration of the 16 USEPA priority PAHs in surface sediments ranged from 42.5 to 158.2 ng/g dry weight with a mean concentration of 126.2 ng/g. The spatial distribution of PAHs was site-specific and combustion processes were the main source of PAHs in the surface sediments. Total 16 priority PAH concentration in the cores 8 and 10 ranged from 77.4 to 305.7 ng/g and from 118.1 to 319.9 ng/g respectively. The variation of the 16 PAH concentrations in both cores followed the economic development in China very well and was also influenced by input pathways. Some of the PAHs were petrogenic in core 8 while pyrolytic source was dominant in core 10. In addition, pyrolytic PAHs in both cores were mainly from the coal and/or grass and wood combustion. A survey of sediments from Daya Bay serves as a baseline study for levels, distributions and possible sources of PAHs in surface sediments and both core sediments.

A molecularly imprinted polymer (MIP) for selective removal of 2,4-dichlorophenol (2,4-DCP) in water was prepared as microspheres by the reverse microemulsion polymerization method based on the non-covalent interactions between 2,4-DCP, oleic acid, and divinylbenzene in acetonitrile. Microspheres have been characterized by Fourier transform infrared spectrometer (FTIR) and energy dispersive X-ray spectrometer (EDS) studies with evidence of 2,4-DCP linkage in polymer particles and scanning electron microscopy (SEM) to study their morphological properties. The proper adsorption and selective recognition ability of the MIP were studied by an equilibrium-adsorption method. The MIP showed outstanding affinity towards 2,4-DCP in aqueous solution and the optimum pH value for binding has been found around the neutral range. The molecular recognition of 2,4-DCP was analyzed in detail by using molecular modeling software. In addition, by investigating the variation in the adsorption ability of the MIP, it clearly showed excellent reproducibility. Molecular imprinting has potential as a remediation technology in water treatment.

The effects of surfactant composition on the ability of chemical dispersants to disperse crude oil in fresh water were investigated. The objective of this research was to determine whether effective fresh water dispersants can be designed in case this technology is ever considered for use in fresh water environments. Previous studies on the chemical dispersion of crude oil in fresh water neither identified the dispersants that were investigated nor described the chemistry of the surfactants used. This information is necessary for developing a more fundamental understanding of chemical dispersion of crude oil at low salinity. Therefore, we evaluated the relationship between surfactant chemistry and dispersion effectiveness. We found that dispersants can be designed to drive an oil slick into the freshwater column with the same efficiency as in salt water as long as the hydrophilic-lipophilic balance is optimum. This study was conducted to advance our understanding of dispersion chemistry in fresh waters.

Animal wastewater lagoons nearby concentrated animal feeding operations (CAFOs) represent the latest tendency in global animal farming, severely impacting the magnitude of greenhouse gas emissions, including nitrous oxide (N₂O). We hypothesized that lagoon wastewater could be supersaturated with N₂O as part of incomplete microbial nitrification/denitrification processes, thereby regulating the N₂O partitioning in the gaseous phase. The objectives of this study were: (i) to investigate the magnitude of dissolved N₂O concentrations in the lagoon; and (ii) to determine the extent to which supersaturation of N₂O occurs in wastewater lagoons. Dissolved N₂O concentrations in the wastewater samples were high, ranging from 0.4 to 40.5 μg N2O mL⁻¹. Calculated dissolved N₂O concentrations from the experimentally measured partition coefficients were much greater than those typically expected in aquatic systems (<0.6 μg N₂O mL⁻¹). Knowledge of the factors controlling the magnitude of N₂O supersaturation could potentially bridge mass balance differences between in situ measurements and global N₂O models. Supersaturation of nitrous oxide may occur in lagoons near concentrated animal feeding operations.

In this study, three river floodplain soils with different compositions of carbonaceous materials and a reference coal sample were extracted with water using the accelerated solvent extraction (ASE) method. The desorption enthalpy values for 2-ring PAHs were highest in the coal sample, with values in the soil samples decreasing with decrease in coal content. The values for the higher condensed PAHs showed that the highest desorption enthalpies were from the samples with the largest amount of coalderived particles. Elevated desorption enthalpies indicated a strong bonding between PAHs and geosorbents. Moreover, with the application of ASE this study was able to conclude that the PAHs in the samples were preferentially adsorbed to carbonaceous materials with high surface areas.