Synthesis of diagnostic quality cancer pathology images by generative adversarial networks.

Deep learning-based computer vision methods have recently made remarkable breakthroughs in the analysis and classification of cancer pathology images. However, there has been relatively little investigation of the utility of deep neural networks to synthesize medical images. In this study, we evaluated the efficacy of generative adversarial networks to synthesize high-resolution pathology images of 10 histological types of cancer, including five cancer types from The Cancer Genome Atlas and the five major histological subtypes of ovarian carcinoma. The quality of these images was assessed using a comprehensive survey of board-certified pathologists (n = 9) and pathology trainees (n = 6). Our results show that the real and synthetic images are classified by histotype with comparable accuracies and the synthetic images are visually indistinguishable from real images. Furthermore, we trained deep convolutional neural networks to diagnose the different cancer types and determined that the synthetic images perform as well as additional real images when used to supplement a small training set. These findings have important applications in proficiency testing of medical practitioners and quality assurance in clinical laboratories. Furthermore, training of computer-aided diagnostic systems can benefit from synthetic images where labeled datasets are limited (e.g. rare cancers). We have created a publicly available website where clinicians and researchers can attempt questions from the image survey (http://gan.aimlab.ca/). © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Partitioning of Aromatic Constituents into Water from Jet Fuels.

A comprehensive study of the most commonly used jet fuels (i.e., Jet A-1 and JP-8) was performed to properly assess potential contamination of the subsurface environment from a leaking underground storage tank occurred in an airport. The objectives of this study were to evaluate the concentration ranges of the major components in the water-soluble fraction of jet fuels and to estimate the jet fuel-water partition coefficients (K fw) for target compounds using partitioning experiments and a polyparameter linear free-energy relationship (PP-LFER) approach. The average molecular weight of Jet A-1 and JP-8 was estimated to be 161 and 147 g/mole, respectively. The density of Jet A-1 and JP-8 was measured to be 786 and 780 g/L, respectively. The distribution of nonpolar target compounds between the fuel and water phases was described using a two-phase liquid-liquid equilibrium model. Models were derived using Raoult's law convention for the activity coefficients and the liquid solubility. The observed inverse, log-log linear dependence of the K fw values on the aqueous solubility were well predicted by assuming jet fuel to be an ideal solvent mixture. The experimental partition coefficients were generally well reproduced by PP-LFER.

The use of carbon fiber/polyetheretherketone (CF/PEEK) in pedicle screw fixation for spinal neoplasms-potential advantages in postoperative imaging and radiotherapy planning.

Background: Titanium pedicle screw fixation complicates postoperative care in patients with spinal neoplasms due to postoperative imaging artefacts and dose perturbation. This study aims to measure the benefits of using carbon fiber/polyetheretherketone (CF/PEEK) pedicle fixation compared to titanium in postoperative imaging, radiotherapy planning and delivery for spinal neoplasms treated with conventional external beam radiotherapy with a commercial treatment planning system. Methods: The properties of CF/PEEK pedicle fixation systems were compared to titanium in radiotherapy dose planning accuracy and postoperative computed tomography (CT) image quality. Dose profiles through the screw, tulip and longitudinal axis of the screw were acquired with radiochromic films and compared to a collapsed cone algorithm simulation, to measure dose agreement. The image quality of postoperative CTs were compared by defining four regions of interest around the vertebrae and screws in water phantom models and previous planning CTs, and comparing calculated artefact indexes (AIs). Results: CF/PEEK screws have non-inferior dosimetric prediction accuracy up to 50 mm beneath the screw for collapsed-cone algorithm planning systems. There is a statistically significant reduction in the absolute difference between calculated and measured dose at a depth of 2 mm beneath the screw. There is minimal attenuation with CF/PEEK relative to the surrounding dose, extending to 50 mm beneath the screw. There is a statistically significant improvement in CT imaging quality with reduced AIs in CF/PEEK fixation compared to titanium in both model and patient CT plans. Conclusions: CF/PEEK pedicle fixation can provide benefits in postoperative imaging and photon radiotherapy planning and delivery to patients with spinal neoplasms.

Patterns of metal accumulation by natural river biofilms during their growth and seasonal succession.

To evaluate the factors influencing patterns of metal accumulation by river biofilms, concentrations of chromium (Cr), nickel (Ni), copper (Cu), and lead (Pb) in biofilms from Erh-Jen River and San-Yeh-Kung Creek were investigated during their growth and seasonal succession. Different metal-accumulation patterns during biofilm development were observed between the two rivers. Mature biofilms (grown for 21-28 days) in both rivers showed maximum metal accumulation (≤3.24 × 10(4), 1.55 × 10(4), 7.40 × 10(3), and 7.80 × 10(2) µg g(-1) of Cr, Ni, Cu, and Pb, respectively) and bioconcentration factors (≤7.15 × 10(5), 1.60 × 10(5), 2.60 × 10(5), and 4.22 × 10(5) l kg(-1) of Cr, Ni, Cu, and Pb, respectively). These types of biofilms had the characteristics of being good metal accumulators and the ability to integrate metal-exposure conditions, suggesting that they were suitable biomonitors for metal-contaminated water. Seasonal succession in metal-accumulation ability of 1-month-old biofilms from Erh-Jen River was mainly affected by changes in bacterial and algal biomass and chemical oxygen demand in water, whereas that from San-Yeh-Kung Creek was primary influenced by concentrations of total nitrogen in water. Synergistic interaction between these four metals on metal-binding sites within biofilms was also shown.

Pembrolizumab with Chemoradiation as Treatment for Muscle-invasive Bladder Cancer: Analysis of Safety and Efficacy of the PCR-MIB Phase 2 Clinical Trial (ANZUP 1502).

BACKGROUND: Radiation may improve the efficacy of immune checkpoint inhibition. This study investigates the combination of pembrolizumab and chemoradiation (CRT) for muscle-invasive bladder cancer (MIBC). OBJECTIVE: To assess the feasibility and safety of pembrolizumab combined with CRT for MIBC. DESIGN, SETTING, AND PARTICIPANTS: A single-arm phase 2 trial was performed with 28 participants having cT2-T4aN0M0 MIBC (Eastern Cooperative Oncology Group performance status 0-1; estimated glomerular filtration rate ≥40 ml/min; no contraindications to pembrolizumab) suitable for CRT. INTERVENTION: Whole bladder radiation therapy (RT; 64 Gy in 32 daily fractions, over 6.5 wk, combined with cisplatin (35 mg/m2 intravenously [IV] weekly, six doses) and pembrolizumab (200 mg IV q3 weeks, seven doses), both starting with RT. Surveillance cystoscopy/biopsy and computerised tomography scans performed 12 and 24 wk after CRT. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary endpoint was feasibility, determined by a prespecified satisfactory low rate of grade 3 or worse nonurinary toxicity or completion of planned CRT according to defined parameters. Secondary endpoints were complete cystoscopic response, locoregional progression-free survival (LRPFS), distant metastasis-free survival (DMFS), and overall survival (OS). RESULTS AND LIMITATIONS: Twenty-eight patients were enrolled with a 31-mo median follow-up. Six had Grade >3 nonurinary adverse events during/within 12 wk after treatment; three had more than one cisplatin dose reduction. The 24-wk post-CRT complete response (CR) rate was 88%. Eight patients developed metastatic disease, and three had nonmetastatic progression. The DMFS at 2 yr is 78% (95% confidence interval [CI] 54-90%), with LRPFS at 2 yr of 87% (95% CI 64-96%) and median OS of 39 mo (95% CI 17.1-not evaluable). Limitations are the single-arm design and sample size. CONCLUSIONS: Combining pembrolizumab with CRT for MIBC was feasible, with manageable toxicity and promising CR rates. PATIENT SUMMARY: Immunotherapy treats nonmetastatic/metastatic bladder cancer effectively. We combined pembrolizumab with chemotherapy and radiation to assess its safety and impact on treatment delivery. The combination was feasible with encouraging early activity. Further larger trials are warranted.

Air Pollution-Related Respiratory Diseases and Associated Environmental Factors in Chiang Mai, Thailand, in 2011-2020.

The unfavorable effects of global climate change, which are mostly the result of human activities, have had a particularly negative effect on human health and the planet's ecosystems. This study attempted to determine the seasonality and association of air pollution, in addition to climate conditions, with two respiratory infections, influenza and pneumonia, in Chiang Mai, Thailand, which has been considered the most polluted city on Earth during the hot season. We used a seasonal-trend decomposition procedure based on loess regression (STL) and a seasonal cycle subseries (SCS) plot to determine the seasonality of the two diseases. In addition, multivariable negative binomial regression (NBR) models were used to assess the association between the diseases and environmental variables (temperature, precipitation, relative humidity, PM2.5, and PM10). The data revealed that influenza had a clear seasonal pattern during the cold months of January and February, whereas the incidence of pneumonia showed a weak seasonal pattern. In terms of forecasting, the preceding month's PM2.5 and temperature (lag1) had a significant association with influenza incidence, while the previous month's temperature and relative humidity influenced pneumonia. Using air pollutants as an indication of respiratory disease, our models indicated that PM2.5 lag1 was correlated with the incidence of influenza, but not pneumonia. However, there was a linear association between PM10 and both diseases. This research will help in allocating clinical and public health resources in response to potential environmental changes and forecasting the future dynamics of influenza and pneumonia in the region due to air pollution.

Spatiotemporal distribution and risk assessment of short-chain chlorinated paraffins in 30 major rivers in Taiwan.

Because of their highly persistent, bioaccumulative and toxic properties, short-chain chlorinated paraffins (SCCPs) have become emerging contaminants and have been included in Annex A (elimination) of the Stockholm Convention since 2017. The contamination of SCCPs has been observed in the environment and biota worldwide but has not been detected in Taiwanese river ecosystems. Thus, this study aimed to determine the occurrence of SCCPs in sediments and fish from 30 major rivers in Taiwan and to evaluate the risk of SCCPs to river ecosystems and human health. The concentrations of SCCPs in sediments and fish ranged from ND (not detected) to 12.6 mg/kg dw and ND to 2.07 mg/kg ww, respectively. The concentrations of SCCPs in sediments were significantly correlated with some indicators of the discharge sources and water quality variables, indicating that SCCPs were released via human activities and various discharges into rivers and accumulated in sediments. The bioaccumulation of SCCPs in fish exhibited species-specific profiles and was related to environmental contamination levels and the living pattern and trophic level of the fish. The SCCP levels in sediments from 20 major rivers in Taiwan might pose a potential ecological risk to river ecosystems according to the criteria of the Federal Environmental Quality Guidelines in Canada, the biota-sediment accumulation factor and the risk quotient. Consumption of SCCP-contaminated river fish by different gender and age groups showed no significant health risk to residents in Taiwan evaluated by the estimated daily intake and hazard quotient. However, there was a health concern for the 0- to 3-year-old group due to the consumption of contaminated river fish at a bioaccessibility of 100% for SCCPs by the margin of exposure. Routine monitoring of SCCPs in river ecosystems is needed to protect aquatic organisms and human health.

Polycyclic aromatic hydrocarbons in 30 river ecosystems, Taiwan: Sources, and ecological and human health risks.

Polycyclic aromatic hydrocarbons (PAHs) are diverse contaminants of global concern because of their ubiquity, toxicity, and carcinogenicity to many organisms, including humans. This study determines the distribution and sources of PAHs in sediments and fish from 30 major rivers in Taiwan, and the risks these PAHs pose to river ecosystems and human health. The total concentrations of 26 PAHs in sediments and fish were 0.016-7.44 mg/kg dw and 0.096-5.51 mg/kg ww, respectively. The PAH composition in sediments differed from that in fish, indicating that sediments may not be the major contributor of PAHs to fish. The accumulation of different PAH compounds in fish was species-specific, depending on the lipid content, living pattern, and trophic level of each fish species, and on the level of environmental contamination. The diagnostic ratios revealed that PAHs in the sediment primarily originated from pyrogenic sources, with some contribution from petrogenic sources. The contribution of each source varied with the sampling site and season. Several water and air quality variables were found to significantly correlate with PAH concentration in sediments and fish, suggesting that PAHs were mainly derived from wastewater discharge and combustion emissions. The 95th percentile risk quotient values suggested that PAHs in sediment from six rivers pose high ecotoxicological risks. The toxic equivalents of benzo[a]pyrene for 16 PAHs in fish were 12-108 µg/kg dw. A human risk assessment using the 95th percentile values of hazard quotient, hazard index, and margin of exposure revealed that the consumption of contaminated fish muscle poses no remarkable risk to human health. However, the 95th percentile carcinogenic risk values indicated that benzo[a]pyrene concentrations in some fish muscles may pose a carcinogenic risk. Benzo[a]pyrene risk management measures are, therefore, necessary.

Factors affecting in situ analysis of total petroleum hydrocarbons in contaminated soils by using a mid-infrared diffuse reflectance spectroscopy.

The hand-held mid-infrared diffuse reflectance infrared Fourier transform (MIR-DRIFT) spectrometer was used to assess the applicability of on-site and real time monitoring of total petroleum hydrocarbons (TPH) in contaminated soils during site characterization and remediation. Field measurement devices (MIR-DRIFT and turbidimetric screening test kits) were used to analyze reference soils with concentration ranging from 713 to 54790 mg/kg and compared with the results by a gas chromatography/mass spectrometry method (GC/MS). In situ field measurement of 147 petroleum-contaminated soil samples from 11 contaminated sites was correlated with laboratory-determined soil TPH levels by GC/MS. The concentrations of TPH by MIR-DRIFT were significantly correlated to the concentrations of TPH by GC/MS. Detection of TPH by the MIR spectrometer was not affected by the weathering effects of diesel-contaminated soils. Soils contaminated by mixed fuels with high content of gasoline constituents may cause the potential interference in MIR measurement. In field practice, interference may be attributed to soil moisture, soil organic matter, and soil texture. Soil moisture below 5% is required to reduce variation of infrared beam reflected from high level of surface liquid. When measuring the contaminated soil with a high organic matter content, the results may be overestimated due to the possible effects of surface reflection and interference. Clay and partial silty clay soils were not suitable for MIR spectrometer detection due to a potential shielding effect to reduce the infrared radiation absorbed by TPH. Future research is warranted to reduce the variation caused by soil texture and heterogeneity in TPH prediction.

Microplastics in water, sediment and fish from the Fengshan River system: Relationship to aquatic factors and accumulation of polycyclic aromatic hydrocarbons by fish.

The occurrence of microplastics was investigated in water, sediment and fish from the Fengshan River system. All collected samples contained microplastics with 334-1058 items/m3 in the water samples, 508-3987 items/kg dry weight in the sediment samples and 14-94 items/fish in the fish samples. The spatial distribution of microplastics in water and sediments was attributed to anthropogenic discharges, flow dynamics, tidal exchanges and microplastic density. This was evidenced by significant correlations of microplastics with the river pollution index (RPI), chemical oxygen demand (COD), suspended solid (SS), flow velocity and the presence of different polymer types of microplastics in water and sediment. Microplastic abundance in fish was correlated to SS, pH and conductivity, indicating that these water quality variables might affect bioavailability of microplastics to fish. Concentrations of microplastics/cm length of demersal fish at a higher trophic level (Leiognathus equulus and Pomadasys argenteus) were higher than those of a benthopelagic fish (Oreochromis niloticus niloticus). The significant relationships observed suggest that collected fish might prefer to ingest long fibrous microplastics from sediments and large fragmented microplastics from water. The high levels of 3- and 4-ring polycyclic aromatic hydrocarbons (PAHs), particularly fluoranthene and pyrene, in fish muscle revealed that the collected fish species might have a high ability to accumulate these PAHs from food and the environment. Significant relationships between some PAHs in fish and microplastic abundances in water/sediments/fish suggested that these PAHs might be accumulated by fish from contaminated microplastics. This study provides unique information on the factors influencing the spatial distribution of microplastics and the role of microplastics on the accumulation of PAHs by fish.

Antibiotic instillation for a chronic lung abscess.

INTRODUCTION: Antibiotic treatment of lung abscesses fails in 10-20% of cases and require surgery, however, some are unsuitable for resection. Alternative options carry significant morbidity. CASE REPORT: A 47 year old man with inoperable non-small cell lung cancer developed a lung abscess following definitive radiotherapy. Initial antibiotic therapy was successful, however four years later his symptoms recurred. Despite multiple courses his symptoms recurred despite long-term antibiotics. Immediately following a diagnostic aspiration, ceftriaxone and metronidazole were instilled into the abscess with subsequent clinical and radiological resolution. DISCUSSION: Lung abscesses are an uncommon complication of radiotherapy. Antibiotic therapy can fail for a number of reasons. Although instillation of antibiotics has not been described in the management of lung abscesses, the direct application of antifungals for aspergillomas is well documented and case series report success in other abscess sites. CONCLUSION: Direct antibiotic instillation following lung abscess aspiration adds minimal risk and is potentially curative.

Emergent contaminants in sediments and fishes from the Tamsui River (Taiwan): Their spatial-temporal distribution and risk to aquatic ecosystems and human health.

The occurrence of emergent contaminants, 24 polybrominated diphenyl ethers (PBDEs), di(2-ethylhexyl)phthalate (DEHP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), diethyl phthalate (DEP), dimethyl phthalate (DMP), di-n-octyl phthalate (DnOP), bisphenol A (BPA) and nonylphenol (NP), was investigated in sediments and fishes collected from the Tamsui River system to determine the factors that influence their distribution and their risk to aquatic ecosystems and human health. The concentrations of total PBDEs, DEHP, DBP, BBP, DEP, DMP, DnOP, BPA and NP in sediments were 1-955, ND-23570, <50-411, <50-430, ND-80, ND-<50, ND-<50, 1-144, 3-19624 µg/kg dw, respectively. The spatial-temporal distribution trends of these compounds in sediments could be attributed to urbanization, industrial discharge and effluents from wastewater treatment plants. The PBDE congener distribution patterns (BDE-209 was the dominant congener) in sediments reflected the occurrence of debromination of BDE-209 and the elution of penta-BDE from the treated products. The concentrations of total PBDEs, DEHP, DBP, BBP, DEP, DMP, DnOP, BPA and NP in fish muscles were 2-66, 17-1046, <10-231, <10-66, <30, ND-<30, ND-<30, 0.4-7 and 3-440 µg/kg ww, respectively. The species-specific bioaccumulation of these compounds by fish was found and four species particularly showed high bioaccumulation potential. BDE-47 was the predominant BDE congener in fish muscles, suggesting high bioavailability and bioaccumulation of this compound. The results of biota-sediment accumulation factors showed that BDE-47, 99, 100, 153 and 154 had relatively high bioavailability and bioaccumulation potential for some fish species. The ecological risk assessment showed that the concentrations of BPA and NP in sediments were likely to have adverse effects on aquatic organisms (risk quotients > 1). The human health risk assessment according to hazard quotients (HQs) and carcinogenic risks (CRs) revealed no remarkable risk to human health through consumption of fish contaminated with BDE-47, 99, 100, 154, 209, DEHP, BPA and NP.

Assessment of genotoxicity of methyl-tert-butyl ether, benzene, toluene, ethylbenzene, and xylene to human lymphocytes using comet assay.

Methyl-tert-butyl ether (MTBE) is a gasoline oxygenate and antiknock additive substituting for lead alkyls currently in use worldwide. Benzene, toluene, ethylbenzene, and xylene (BTEX) are volatile monoaromatic hydrocarbons which are commonly found together in crude petroleum and petroleum products such as gasoline. The aim of this study is to evaluate the genotoxic effects of these tested chemicals in human lymphocytes. Using the alkaline comet assay, we showed that all of the tested chemicals induce DNA damage in isolated human lymphocytes. This effect could follow from the induction of DNA strands breaks. The neutral version of the test revealed that MTBE, benzene, and xylenes induce DNA double-strand breaks at 200 microM. Apart from MTBE, the spin traps, 5,5-dimethyl-pyrroline-N-oxide (DMPO) and N-tert-butyl-alpha-phenylnitrone (PBN) can decrease the level of DNA damage in BTEX at 200 microM. This indicated that DNA damage could result from the participation of free radicals in DNA-damaging effect, which was further supported by the fact that post-treatment of formamidopyrimidine-DNA glycosylase (Fpg), enzyme recognizing oxidized DNA purines, gave rise to a significant increase in the extent of DNA damage in cells treated with benzene, and xylene at 200 microM. The results obtained suggested that MTBE and BTEX could induce a variety type of DNA damage such as single-strand breaks (SSBs), double-strand breaks (DSBs), and oxidative base modification.

Epidemiological, clinical and climatic characteristics of dengue fever in Kaohsiung City, Taiwan with implication for prevention and control.

BACKGROUND: The early identification of dengue infection is essential for timely and effective quarantine and vector control measures for preventing outbreaks of the disease. Kaohsiung City is responsible for most of the dengue cases in Taiwan. Thus, this study aims to identify major factors involved in the prevalence of dengue fever by analyzing the epidemiological and clinical characteristics, and to establish associations between weather parameters and dengue occurrence in this City. METHODS: A retrospective study was conducted with 3,322 confirmed dengue cases. Appropriate statistical methods were used to compare differences and correlations between dengue occurrence and demographic, clinical and weather parameters. RESULTS: The outbreak of dengue fever was found to be initiated by imported cases of dengue viruses from other endemic countries. Most of the confirmed cases were not reported to the health authority during the first visit to a doctor, and it took a median of 5 days after the appearance of the first syndromes for medical personnel to report suspected dengue cases. Accordingly, Aedes mosquitoes would have enough time to be infected and transmit the dengue virus. The diagnosis and notification criteria should not only include common symptoms of fever, myalgia, headache, skin rash and arthralgia, but should also be adjusted to include the most frequent symptoms of loss of appetite and feeling thirsty to shorten the notification time. Significantly positive correlations were found between the number of confirmed cases and weather parameters (i.e., temperature, rainfall and relative humidity) at a time lag of 1 month and 2 months. The predictive models for dengue occurrence using these three parameters at a 2-month lag time were established. CONCLUSIONS: The surveillance of imported cases, adjustment of notification criteria and application of climatic predictive models would be helpful in strengthening the dengue early warning surveillance system.

Performance characteristics of the limulus amebocyte lysate assay and gas chromatography-mass spectrum analysis of lipopolysaccharides relative to nitric oxide production by peritoneal exudates of cells.

Limulus amebocyte lysate (LAL) assay and gas chromatography-mass spectrum (GC-MS) analysis are usually used for the quantification of lipopolysaccharides (LPS) from the environment. The LAL assay measures endotoxin units to represent the LPS biological function but GC-MS analysis measures decanoic (C(10:0)) and dodecanoic (C(12:0)) 3-hydorxy fatty acids (3-OH FA) concentration to represent the LPS chemical composition. A study was carried out using these methods to evaluate their degree of correlation. Using the culture supernatants of 30 independent strains of Pseudomonas aeruginosa, the bacterial supernatants gave of 0.53+/-0.45 and 2.49+/-1.75mg/l of C(10:0) and C(12:0) 3-OH FA, respectively, compared to 17.96+/-13.28mg/l of LPS with the LAL assay (1ng/ml of LPS congruent with0.78EU/ml). The 3-OH FA concentration relative to the endotoxin unit dose in the supernatants exhibited a positive correlation (r(2)=0.5182, C(10:0); r(2)=0.4359, C(12:0)). When supernatants having a high level of endotoxin were used to treat peritoneal exudates cells, nitric oxide (NO) was generated in a dose-dependent manner (r(2)=0.6174). To determine if either C(10:0) or C(12:0) 3-OH FA can act as an indictor of LPS quantity was correlated with this immunostimulatory effect, the correlation of these 3-OH FA concentrations against the produced NO levels was evaluated. This also exhibited a positive correlation; however, the two indicators of 3-OH FA gave different dose-responsible performances (r(2)=0.3211, C(10:0); r(2)=0.4527, C(12:0)).

Ecological risk assessment for aquatic species exposed to contaminants in Keelung River, Taiwan.

An ecological risk assessment was conducted for Keelung River in northern Taiwan. The objective of this study was to assess the risk to fish, aquatic insects, and benthic macroinvertebrates associated with chemical-of-potential-concern (COPC) in the river and to rank ecological risk for these chemicals. The protection of at least 95% of the species 90% of the time from acute and chronic COPC exposures was the defined assessment endpoint. Nine inorganic and organic contaminants were selected to evaluate the impact to aquatic community in the Keelung River. The quotient method served as screen level estimation of risk. The Aquatic Ecological Risk Assessment model was used to analyze exposure and ecological effects and to estimate community level risk. The logarithmic regression model between probability and lethal concentration was established. The combined risks of multiple chemicals were evaluated under assumption of additive risk. The results indicated that zinc and copper pose higher risk among metals. Ammonia, copper, and zinc posed virtually all of the risk, while organic COPCs posed a negligible risk. Potential ecological risk from ammonia exposure was greatest. The probability of more than 5% of the species being affected by acute or chronic toxicity of COPCs is about 100%. In average (50% of the time), 99% of the species would be affected by acute toxicity of COPCs, and about all the species would be affected by chronic toxicity of COPCs. Uncertainties in this assessment were associated with variability in ecosystem stressors, exposure data, ecological effect data, and risk characterization.

Oxygenated fuel induced cosolvent effects on the dissolution of polynuclear aromatic hydrocarbons from contaminated soil.

The cosolvent-induced dissolution of polynuclear aromatic hydrocarbons (PAHs) from contaminated soil caused by oxygenated fuel spills was studied. Oxygenated fuel induces a solvent flushing effect on the contaminated soil due to the high content of oxygenated compounds (i.e., methanol, ethanol, and methyl tert butyl ether (MTBE)). The miscible displacement techniques were applied to evaluate the increased potential for secondary contamination in an impacted site. Significant solubility enhancement of the 18 PAHs monitored during fuel spill simulation and cosolvent flushing is clearly evident when compared to normal water dissolution. The breakthrough concentration profile for each PAH constituent was integrated over the cumulative effluent volume (i.e., the zeroth moment) to determine the total PAH mass removed during the experiment. The removal efficiency of PAHs ranges from 46.6% to 99.9% in three oxygenated fuels (i.e., M85, E85, and oxygenated gasoline) during the fuel spill. Several factors including hydrophobicity of compounds, nonequilibrium dissolution due to nonuniform coal tar distribution, and heterogeneous media properties affect the oxygenated compound-induced dissolution process. This study provides a basis to predict the facilitated transport of hydrophobic organic compounds from subsurface environment due to the cosolvent effects of oxygenated fuels.

Assessing soil and groundwater contamination from biofuel spills.

Future modifications of fuels should include evaluation of the proposed constituents for their potential to damage environmental resources such as the subsurface environment. Batch and column experiments were designed to simulate biofuel spills in the subsurface environment and to evaluate the sorption and desorption behavior of target fuel constituents (i.e., monoaromatic and polyaromatic hydrocarbons) in soil. The extent and reversibility of the sorption of aromatic biofuel constituents onto soil were determined. When the ethanol content in ethanol-blended gasoline exceeded 25%, enhanced desorption of the aromatic constituents to water was observed. However, when biodiesel was added to diesel fuel, the sorption of target compounds was not affected. In addition, when the organic carbon content of the soil was higher, the desorption of target compounds into water was lower. The empirical relationships between the organic-carbon normalized sorption coefficient (Koc) and water solubility and between Koc and the octanol-water partition coefficient (Kow) were established. Column experiments were carried out for the comparison of column effluent concentration/mass from biofuel-contaminated soil. The dissolution of target components depended on chemical properties such as the hydrophobicity and total mass of biofuel. This study provides a basis for predicting the fate and transport of hydrophobic organic compounds in the event of a biofuel spill. The spill scenarios generated can assist in the assessment of biofuel-contaminated sites.

Biodegradation of carbamate pesticides by natural river biofilms in different seasons and their effects on biofilm community structure.

This study investigated the ability of natural river biofilms from different seasons to degrade the carbamate pesticides methomyl, carbaryl and carbofuran in single and multiple pesticide systems, and the effects of these pesticides on algal and bacterial communities within biofilms. Spring biofilms had the lowest biomass of algae and bacteria but showed the highest methomyl degradation (>99%) and dissipation rates, suggesting that they might contain microorganisms with high methomyl degradation abilities. Degradation of carbofuran (54.1-59.5%) by biofilms in four seasons was similar, but low degradation of carbaryl (0-27.5%) was observed. The coexistence of other pesticides was found to cause certain effects on pesticide degradation and primarily resulted in lower diversity of diatoms and bacteria than when using a single pesticide. The tolerant diatoms and bacteria potentially having the ability to degrade test pesticides were identified. River biofilms could be suitable biomaterials or used to isolate degraders for bioremediating pesticide-contaminated water.

The potential role of water quality parameters on occurrence of nonylphenol and bisphenol A and identification of their discharge sources in the river ecosystems.

Nonylphenol (NP) and bisphenol A (BPA) have attracted great attention due to their estrongenic activities and occurrence in different environments. This study investigated concentrations of NP and BPA in water and sediments of 16 major rivers in Taiwan to determine their association with water quality parameters on their distribution. The sources of NP and BPA discharged into river environments were also identified. The results showed that concentrations of NP and BPA were in the range of 0.02-3.94 and 0.01-44.65µgL(-1) in water and 6.59-47797.69 and 0.37-491.54µgkg(-1) dry weight in sediments. High levels of NP and BPA in water and sediments were measured in sampling sites near highly industrialized and urbanized areas. Construction of the sewage system and wastewater treatment plant has decreased these chemicals discharged into Love River. Dilution effects and erosion of surface sediments in the high-flow season resulted in lower concentrations of NP and BPA detected in sediments of most rivers than those in the low-flow season. Occurrence characteristics of NP and BPA in water and sediments were mainly related to organic carbon contents in sediments and several water quality parameters such as dissolved oxygen, pH, concentrations of ammonia-nitrogen and total organic carbon in water. Effluents from NP/BPA-related factories appeared to be the major discharge sources of NP and BPA. Use and waste of BPA-containing products in household activity was the another discharge source of BPA, but handling NP-containing products became an important source of NP only in the low-flow season.