2-(4-Chlorophenyl)benzo-1,4-quinone induced ROS-signaling inhibits proliferation in human non-malignant prostate epithelial cells

Polychlorinated biphenyls (PCBs) and their metabolites are environmental chemical contaminants which can produce reactive oxygen species (ROS) by auto-oxidation of di-hydroxy PCBs as well as the reduction of quinones and redox-cycling. We investigate the hypothesis that 2-(4-chlorophenyl)benzo-1,4-quinone (4-Cl-BQ), a metabolite of 4-chlorobiphenyl (PCB3), induced ROS-signaling inhibits cellular proliferation. Monolayer cultures of exponentially growing asynchronous human non-malignant prostate epithelial cells (RWPE-1) were incubated with 0–6 μM of 4-Cl-BQ and harvested at the end of 72 h of incubation to assess antioxidant enzyme expression, cellular ROS levels, cell growth, and cell cycle phase distributions. 4-Cl-BQ decreased manganese superoxide dismutase (MnSOD) activity, protein, and mRNA levels. 4-Cl-BQ treatment increased dihydroethidium (DHE) fluorescence, which was suppressed in cells pretreated with polyethylene glycol conjugated superoxide dismutase (PEG-SOD). The increase in ROS levels was associated with a decrease in cell growth, and an increase in the percentage of S-phase cells. These effects were suppressed in cells pretreated with PEG-SOD. 4-Cl-BQ treatment did not change the protein levels of phosphorylated H2AX at the end of 72 h of incubation, suggesting that the inhibition in cell growth and accumulation of cells in S-phase at the end of the treatments were probably not due to 4-Cl-BQ induced DNA double strand break. These results demonstrate that MnSOD activity and ROS-signaling perturb proliferation in 4-Cl-BQ treated in vitro cultures of human prostate cells.     

Inferring coastal processes from regional-scale mapping of Radon and salinity: examples from the Great Barrier Reef, Australia

The radon isotope ²²²Rn and salinity in coastal surface water were mapped on regional scales, to improve the understanding of coastal processes and their spatial variability. Radon was measured with a surface-towed, continuously recording multi-detector setup on a moving vessel. Numerous processes and locations of land-ocean interaction along the Central Great Barrier Reef coastline were identified and interpreted based on the data collected. These included riverine fluxes, terrestrially-derived fresh submarine groundwater discharge (SGD) and the tidal pumping of seawater through mangrove forests. Based on variations in the relationship of the tracers radon and salinity, some aspects of regional freshwater inputs to the coastal zone and to estuaries could be assessed. Concurrent mapping of radon and salinity allowed an efficient qualitative assessment of land-ocean interaction on various spatial and temporal scales, indicating that such surveys on coastal scales can be a useful tool to obtain an overview of SGD locations and processes.     

PAH air pollution at a Portuguese urban area: carcinogenic risks and sources identification

This study aimed to characterize air pollution and the associated carcinogenic risks of polycyclic aromatic hydrocarbon (PAHs) at an urban site, to identify possible emission sources of PAHs using several statistical methodologies, and to analyze the influence of other air pollutants and meteorological variables on PAH concentrations.The air quality and meteorological data were collected in Oporto, the second largest city of Portugal. Eighteen PAHs (the 16 PAHs considered by United States Environment Protection Agency (USEPA) as priority pollutants, dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were collected daily for 24 h in air (gas phase and in particles) during 40 consecutive days in November and December 2008 by constant low-flow samplers and using polytetrafluoroethylene (PTFE) membrane filters for particulate (PM₁₀ and PM_2.5 bound) PAHs and pre-cleaned polyurethane foam plugs for gaseous compounds. The other monitored air pollutants were SO₂, PM₁₀, NO₂, CO, and O₃; the meteorological variables were temperature, relative humidity, wind speed, total precipitation, and solar radiation. Benzo[a]pyrene reached a mean concentration of 2.02 ng?m^?3, surpassing the EU annual limit value. The target carcinogenic risks were equal than the health-based guideline level set by USEPA (10^?6) at the studied site, with the cancer risks of eight PAHs reaching senior levels of 9.98?×?10^?7 in PM₁₀ and 1.06?×?10^?6 in air. The applied statistical methods, correlation matrix, cluster analysis, and principal component analysis, were in agreement in the grouping of the PAHs. The groups were formed according to their chemical structure (number of rings), phase distribution, and emission sources. PAH diagnostic ratios were also calculated to evaluate the main emission sources. Diesel vehicular emissions were the major source of PAHs at the studied site. Besides that source, emissions from residential heating and oil refinery were identified to contribute to PAH levels at the respective area. Additionally, principal component regression indicated that SO₂, NO₂, PM₁₀, CO, and solar radiation had positive correlation with PAHs concentrations, while O₃, temperature, relative humidity, and wind speed were negatively correlated.     

Application of 15N–18O double stable isotope tracer technique in an agricultural nonpoint polluted river of the Yangtze Delta Region

One strategy to combat nitrate (NO₃-N) contamination in rivers is to understand its sources. NO₃-N sources in the East Tiaoxi River of the Yangtze Delta Region were investigated by applying a ¹⁵N–¹⁸O dual isotope approach. Water samples were collected from the main channel and from the tributaries. Results show that high total N and NO₃-N are present in both the main channel and the major tributaries, and NO₃-N was one of the most important N forms in water. Analysis of isotopic compositions (δ ¹⁸O, δD) of water suggests that the river water mainly originated from three tributaries during the sampling period. There was a wide range of δ ¹⁵N-NO₃ (?1.4 to 12.4 ‰) and a narrow range of δ ¹⁸O-NO₃ (3.7 to 9.0 ‰) in the main channel waters. The δ ¹⁵N and δ ¹⁸O-NO₃ values in the upper, middle, and lower channels along the river were shifted as 8.2, 3.5, and 9.5 ‰, and 9.0, 4.2, and 6.0 ‰, respectively. In the tributary South Tiao, the δ ¹⁵N and δ ¹⁸O-NO₃ values were as high as 9.5 and 7.0 ‰, while in the tributaries Mid Tiao and North Tiao, NO₃-N in most of the samples had relatively low δ ¹⁵N and δ ¹⁸O-NO₃ values from 2.3 to 7.5 ‰ and 4.7 to 7.0 ‰, separately. Our results also suggest that the dual isotope approach can help us develop the best management practice for relieving NO₃-N pollution in the rivers at the tributary scale.     

Beyond selectivity: Are behavioral avoidance and hormesis likely causes of pyrethroid-induced outbreaks of the southern red mite Oligonychus ilicis?

Secondary pest outbreak is a counterintuitive ecological backlash of pesticide use in agriculture that takes place with the increase in abundance of a non-targeted pest species after pesticide application against a targeted pest species. Although the phenomenon was well recognized, its alternative causes are seldom considered. Outbreaks of the southern red mite Oligonychus ilicis are frequently reported in Brazilian coffee farms after the application of pyrethroid insecticides against the coffee leaf miner Leucoptera coffeella. Selectivity favoring the red mite against its main predatory mites is generally assumed as the outbreak cause, but this theory has never been tested. Here, we assessed the toxicity (and thus the selectivity) of deltamethrin against both mite species: the southern red mite and its phytoseid predator Amblyseius herbicolus. Additionally, behavioral avoidance and deltamethrin-induced hormesis were also tested as potential causes of red mite outbreak using free-choice behavioral walking bioassays with the predatory mite and life-table experiments with both mite species, respectively. Lethal toxicity bioassays indicated that the predatory mite was slightly more susceptible than its prey (1.5×), but in more robust demographic bioassays, the predator was three times more tolerant to deltamethrin than its prey, indicating that predator susceptibility to deltamethrin is not a cause of the reported outbreaks. The predator did not exhibit behavioral avoidance to deltamethrin; however insecticide-induced hormesis in the red mite led to its high population increase under low doses, which was not observed for the predatory mite. Therefore, deltamethrin-induced hormesis is a likely cause of the reported red mite outbreaks.     

Progress in High-Temperature Electrostatic Precipitation

Current-voltage relationships for negative corona are given for a pilot-scale electrostatic precipitator with 3-in. electrode spacing at 80°–1500°F and 35–80 psig. Direct comparison is made with the electrical characteristics for a 1-in. spacing at 1200°F over the same pressure range. Experimental results on both spacing agree well with electrostatic theory. Initial dust removal efficiencies for the pilot-scale precipitator ranged from 90 to 98% at 1460°F and 80 psig, but continuous operation was not achieved owing to excessive thermal expansion of the internal parts of the unit.     

Ozone Injury to Pinus Strobus

In a study of the ozone-induced needle blight of eastern white pine in central New York, acute injuries naturally induced on field trees during a year of relatively low ozone concentrations (1 966) were compared with injuries induced during a year of higher concentrations (1967). Injuries were more frequent and severe and were associated with higher mean ozone concentrations in 1967 than in 1966. Characteristic symptoms were induced on foliage of pine branches exposed to controlled doses of ozone as low as 7 ± 1 pphm for four hours or 3 ± 1 pphm for 48 hours. Such doses were equalled or exceeded two and four times, respectively, in the field during the 1 967 season. Ozone sensitivity of pine needle tissue was increased by fumigation in atmospheres containing water mist. High concentrations of ozone (40-60 pphm) caused general injury of foliage of both ozone-susceptible and resistant trees; the symptoms were unlike those found in the field or caused by fumigation with low concentrations of ozone.     

Canada’s Mobile Sources Air Pollution Control Program

The chemical and optical properties of particle emissions from onroad vehicles were investigated at the Allegheny Tunnel on the Pennsylvania Turnpike during July 1981. The optical results are in agreement with earlier data: (1) in terms of light extinction per km driven, diesel particle emissions are at least an order of magnitude more important than particle emissions from spark-ignition vehicles; (2) for diesel particle emissions, light absorption is about twice as efficient as light scattering. Chemical analyses showed that: (1) 24% of the vehicle aerosol was extractable material, (2) 75% of the total mass was carbon, (3) 55% of the total mass was unextractable (elemental) carbon, and (4) the stoichiometry of the extractable fraction of the diesel particle emissions was C_nH_t.7nN_0.05n , i.e., the extractable material was composed predominantly of alkanes. The results of the chemical analyses allow the calculation of the massspecific light absorption coefficient for the elemental carbon component of the diesel particle emissions, i.e., 10.9 ± 1.8 m²/g (500 nm).     

Testing and Commercialization of Byproduct Dibasic cids as Buffer Additives for Limestone Flue Gas esulfurization Systems

Pilot plant (0.1 MW) tests and utility boiler full scale demonstration (194 MW) of byproduct organic dibasic acids (DBA) as buffer additives to limestone scrubbers have shown performance improvements equivalent to those achieved by the addition of pure adipic acid. Both SO₂ removal efficiency and limestone utilization increased, and no significant operating problems were observed with three of the four DBA tested. Chemical and biological evaluations of scrubber samples taken during the DBA testing indicated no detectable tOxicity or mutagenicity, and no significant environmental impact is expected as a result of DBA addition. Economic estimates indicate that substitution of DBA for pure adipic acid as a buffer additive will result in additive cost savings of 30 % or greater.