Hydrological and environmental conditions as key drivers for spatial and seasonal changes in PCDD/PCDF concentrations, transport and deposition along urban cascade reservoirs

To investigate the drivers for transport and deposition of 17 2,3,7,8-substituted PCDDs/PCDFs along an urban river, water samples from five reservoirs located along the river course were collected in January and July 2008. The concentrations of 17 congeners of PCDD/PCDF were determined and compared to environmental - physical, chemical and biological - conditions. The obtained data revealed that the concentration of the sum of toxic PCDDs/PCDFs in water samples differ between reservoirs as well as between seasons, ranging from 12.04 pg L(-1) in UP (first in the cascade) to 1327.94 pg L(-1) in PR (last in the cascade) during winter of 2008; and from 34.94 pg L(-1) in UP to 1352.50 pg L(-1) in TR (next to last) in summer 2008. In comparison, water samples collected from the river had a concentration several times lower at the first two sites (sites no. 1 and 4) and no detectable values at the last three stations (sites no. 7, 8, 10). The obtained data demonstrated strong or moderate correlations between the sum of 17 PCDDs/PCDFs and TEQ in reservoir water samples and physical, chemical and biological conditions, such as: Mg(2+) (R=0.82; R=0.80, respectively), SO(4)(2-) (R=0.80; R=0.80, respectively), K(+) (R=0.80; R=0.80, respectively), Ca(2+) (R=0.67, R=0.70, respectively), OSM (R=0.63, R=0.70, respectively). In addition, the positive strong correlation between TEQ concentrations and the water temperature (R=0.63) and chlorophyll a content (R=0.90) was noted. The violent weather conditions occurred during the research season with periods of intensive storm events (up to 32 mm in mid July), and thus the increased river flow velocity (up to 0.45 m(3)s(-1)) could have a direct and indirect influence on PCDDs/PCDFs concentration through changes in the sedimentation/resuspension ratio and consequently in transport, deposition and degradation processes along the river/reservoirs.     

Comparison of DAYCENT-simulated and measured nitrous oxide emissions from a corn field

Accurate assessment of N(2)O emission from soil requires continuous year-round and spatially extensive monitoring or the use of simulation that accurately and precisely predict N(2)O fluxes based on climatic, soil, and agricultural system input data. DAYCENT is an ecosystem model that simulates, among other processes, N(2)O emissions from soils. The purpose of the study was to compare N(2)O fluxes predicted by the DAYCENT model to measured N(2)O fluxes from an experimental corn field in central Iowa. Soil water content temperature and inorganic N, simulated by DAYCENT were compared to measured values of these variables. Field N(2)O emissions were measured using four replicated automated chambers at 6-h intervals, from day of year (DOY) 42 through DOY 254 of 2006. We observed that DAYCENT generally accurately predicted soil temperature, with the exception of winter when predicted temperatures tended to be lower than measured values. Volumetric water contents predicted by DAYCENT were generally lower than measured values during most of the experimental period. Daily N(2)O emissions simulated by DAYCENT were significantly correlated to field measured fluxes; however, time series analyses indicate that the simulated fluxes were out of phase with the measured fluxes. Cumulative N(2)O emission calculated from the simulations (3.29 kg N(2)O-N ha(-1)) was in range of the measured cumulative N(2)O emission (4.26 +/- 1.09 kg N(2)O-N ha(-1)).     

An analysis of the dust deposition on solar photovoltaic modules

Environmental Science and Pollution Research - Solid particles impair the performance of the photovoltaic (PV) modules. This results in power losses which lower the efficiency of the system as well...     

Environmental justice in Appalachia Ohio? An expanded consideration of privilege and the role it plays in defending the contaminated status quo in a white,working-class community

Environmental justice addresses inequitable distributions of health risks from exposure to pollution and other hazards. Appalachian residents of southeastern Ohio who live along the Ohio River are disproportionately subject to industrial pollution. Of particular concern is the DuPont Washington Works plant where perfluorooctanoic acid, or C8, was used to make consumer products. Although company officials became aware in 1984 that the water supply of Little Hocking, Ohio, was tainted with C8 coming from its plant, residents were not notified until 2002. Subsequent studies determined a number of health problems, including cancer, are linked to residents’ exposure. This qualitative study asked Little Hocking residents and environmental regulators if they consider C8 contamination in Little Hocking an injustice. Results indicate a lack of consensus – even among affected residents – concerning DuPont's^® actions as constituting an injustice. This finding, among others, is used to argue that many residents in Little Hocking, through their association with DuPont^®, benefit from class-based forms of privilege and seek to maintain them in the context of immobility and economic uncertainty. This explains why some communities may be considered an environmental justice community from an academic standpoint, but not self-identify as such. However, maintaining privilege at the local scale in the context of weak regulation enhances exploitation in Little Hocking while contributing to power at extra-local scales. Thus, environmental justice activists in white, working-class communities must overcome the challenge posed by privilege that defends the contaminated status quo.     

Adsorptive micellar flocculation as an efficient method for processing soil extracts containing both surfactant and polychlorinated biphenyls: practical demonstration.

The main purpose of the paper is to share the results and experience from processing soil extracts containing a high concentration of both anionic surfactant and polychlorinated biphenyls (PCBs) by use of method the called adsorptive micellar flocculation. The method is similar to coagulation, but the mechanism is more complicated. The flocculants examined in the laboratory section involved ferric chloride, aluminium chloride, ferric sulfate, and aluminum sulfate. It was observed that ferric chloride provides the best PCB removal efficiency from the extract. Subsequently, two extracts obtained from the pilot-scale demonstration of the PCBs leaching from the soils by the surfactant solution were processed by this method. The volume of the extracts processed was several hundred liters. The method proved it can remove PCBs from all extracts with a very high efficiency (greater than 99.99%). The residual PCB concentrations in solution were less than 1 microg/L.     

Levels of PCDDs, PCDFs, and PCBs in the blood of the non-occupationally exposed residents living in the vicinity of a chemical plant in the Czech Republic

In 2003, concentrations of altogether 17 PCDD/Fs congeners and 12 non-ortho and mono-ortho dioxin-like PCBs were measured in the blood of 60 randomly selected adults who lived in three settlements surrounding a chemical plant that had been producing chlorinated herbicides (mainly HCHs, HCB, pentachlorophenole, 2,4,5-T) in the 1960's; subjects consuming home-produced animal foods were chosen. Twenty blood donors with similar characteristics from the locality with about 80 km distance were used as control subjects. The factors that influenced the dioxin levels were investigated on the basis of a questionnaire. The aim of our study was to find out whether the residents living in the surroundings of the chemical plant are at a greater exposure risk than the controls. To calculate TEQ values, WHO-TEFs were used. The concentrations of four PCDD and six PCDF congeners were below the LOD in more than 50% of samples. Significantly higher WHO-TEQ levels (p<0.05) were found for PCDDs, PCDFs, or PCBs in all three followed up groups compared with controls. The geometric means of the total TEQ values for PCDD/F/PCBs were 43.8, 50.2, and 40.0 pg/g fat compared to 23.2 pg/g fat in the control. The percentages of TEQ due to the measured congeners in exposed groups were 9-10.3% for PCDDs, 20.5-26.9% for PCDFs, 19.2-23.1% for coplanar and 43.6-47.2% for mono-ortho PCBs. In control, the percentage of TEQ was 11.6, 26.7, 24.1, and 37.5%. PCBs, predominantly PCB156, followed by PCB126 contributed 60 to 70% of the total TEQ value. Positive correlation of the PCDD/PCDF/PCB blood levels with age and with consumption of locally produced eggs was found.     

Application of physicochemical data for water-quality assessment of watercourses in the Gdansk Municipality (South Baltic coast)

The paper presents water-quality evaluation based on an 8-year monitoring programme in the Gdansk Municipality region, on the Southern coast of the Baltic Sea. The studies were carried out from 2000 to 2007 by surface water analysis at 15 various sites within eight watercourses. Sampling sites included rather urbanized or developed lands, farming fields and non-polluted city recreational areas such as parks and forests. Most of the watercourses were sampled monthly at two locations, one within the upper course of the watercourse and the other near its mouth. In all samples, eight parameters of water quality were determined: total suspended solids, dissolved oxygen, water temperature, oxygen saturation, 5-day biochemical oxygen demand, chemical oxygen demand, total phosphorus and total nitrogen concentration. Interpretation of the obtained results revealed that examination of those basic physicochemical parameters permits to discriminate initially watercourses with respect to level of water contamination. During the research, a large dataset was obtained and it was described by both basic statistical parameters and chemometric method of cluster analysis. The paper presents relations between analysed parameters and influence of land exploitation mode on water quality and describes variation of the results both in space and time.     

Anaerobic Biodegradation of Polymer Composites Filled with Natural Fibers

Polymer composites with natural fibers prepared by melt blending were investigated. Synthetic and natural macromolecules were used, including poly(lactic acid), polyhydroxybutyrate-co-polyhydroxyvalerate and low density polyethylene. These polymers were filled with flax fibers. Mechanical properties of the composites, biogas production and mass loss under anaerobic digestion have been presented. It has been shown that the mechanical properties sustain after 28 days of biodegradation. Such materials can be found in applications as packaging, as well as in medicine as polymeric scaffolds, and drug delivery systems etc.     

Feedstock recycling of waste polymers by thermal cracking in molten metal: thermodynamic analysis

Waste plastics contribute to serious environmental and social problems, such as the loss of natural resources, environmental pollution, and depletion of landfill space, but they also create demands on the environmentally-oriented part of the society. Feedstock recycling of scrap polymers by thermal and chemical methods is well known and environmentally accepted. The paper presents the results of thermodynamic analysis of the conversion of polyolefins in a fuel-like mixture of hydrocarbons using thermal cracking in a new type of tubular reactor with molten metal. Evaluation of the efficiency of the process was based on exergy calculations. Calculated exergy efficiency was ca. 79.5 %. It means that feedstock recycling of waste is better from an energetic and environmental point of view than other processes, particularly incineration.     

Application of various methods to determine the lipophilicity parameters of the selected urea pesticides as predictors of their bioaccumulation

Different lipophilicity procedures including a newly developed (based on O?cik's equation) was applied in order to compare various urea pesticides with herbicidal and also insecticidal activity, such as monolinuron, chlorotoluron, diuron, isoproturon, linuron, dimefuron, diflubenzuron, teflubenzuron and lufenuron. Lipophilicity parameters (R_MWS and R_MW0) of nine examined pesticides were determined on the chromatographic plates RP-8F₂₅₄ with the use of methanol–water as a mobile phase_. Similarity analysis enabled to group all examined pesticides depending on their lipophilic character and allowed to perform a more objective comparison of different lipophilicity parameters obtained for investigated compounds by means of thin-layer chromatography and by the use of computational methods. It was stated that with the number of fluorine in examined pesticides, the lipophilic character of insecticides and also their tendency to bioaccumulation in the living systems increases noticeably. The results of this work confirmed that a new procedure for determining the lipophilicity parameter (R_MW0) by O?cik's equation could be a suitable tool in the prediction of pesticide bioaccumulation in living system and may be used as an indicator in design of new urea pesticides, which will be safe for humans and the environment.