Frame and daughters directives for evaluating the ambient air quality have been adopted by the EU as a part of the new strategies for pollution prevention and control and environmental management. Therefore, the prediction of ozone concentration and the identification of episodes by modeling are fundamental for protecting and preventing the population and environment against the harmful effects of this species. Under this approach, ambient air quality (immission) data in three zones: A Guarda, Corrubedo and Verín (two coastal and one interior) of Galicia (NW Spain), were collected and evaluated using statistical tools. Punctual and functional background and standard levels of ozone and NOx in the three zones have been determined for detecting abnormal situations and identifying possible emission sources. With this aim, threshold values were established by defining confidence levels. Finally, ozone concentration has been forecasted by time series modeling. Descriptive and predictive models of ozone involving different parameters depending of the area considered have been developed. Satisfactory estimation of ozone concentration was obtained in the three cases with proved efficiency, since predictive values did not exceed the 95% confidence level.

This study determined the content of trace elements in coal ash collected from a coal-fired thermal power plant using local coal from Sawarak, Malaysia. This is crucial for the potential impact on the geoenvironment from its disposal and utilization; as coal ash has recently been produced locally in substantial amounts and very limited data is available. The trace elements concentrations presents in coal ashes are compared with the reported coal ash concentrations and the risk for the local wet tropical geoenvironment from the perspective of its vulnerability to these is studied for an indication of potential environmental implications on the wet tropics. The trace elements were found to be in concentrations that, if applied or inadvertently released into the environmental media, present a potential hazard and further necessary research in this regard is indicated.

The need for solutions to minimize the negative environmental impacts of anthropogenic activities Fhas increased. Sewage sludge is composed of predominantly organic matter and can be used to improve soil characteristics, such as fertility. Therefore, its application in agriculture is an adequate alternative for its final disposal. However, there is a lack of information on its long-term effects on soil changes in tropical areas. Thus, the objectives of this study were to determine (i) the effect of sewage sludge application on heavy metal build-up in soil and maize grains and leaves, and (ii) the effects of soil amendment with sewage sludge on the chemical properties of a Brazilian oxisol. Besides the increasing levels of Zn, Cu, Ni, and Cr, amending soil with sewage sludge also alters the distribution of these metals by increasing the mobile Phases, which correlated significantly with the increase in metal extraction with two single extractants, Mehlich 1 and DTPA (Diethylene triamine pentaacetic acid). The levels of Fe, Mn, Zn, and Cu in maize grains and leaves increased with the type and rate of sewage sludge application. Nevertheless, metal build-up in soil and plants was within the allowed limits. Significant differences were also found in soil characteristics like humic fractionation with the applied sewage doses. The data obtained does not indicate any expressive drawbacks in the use of sewage sludge as a soil amendment, as the heavy metal concentrations observed are unlikely to cause any environmental or health problems, even overestimated loadings, and are in accordance with the Brazilian regulations on farming land biosolid disposal.

The concentrations of As and Zn in 100 georeferenced soils uniformly distributed throughout the area affected by the spill from the Aznalcóllar mine (April 1998) were analysed at three depths (0-10, 10-30, and 30-50 cm) and on four dates (autumn-winter 1998, 1999, 2001, and 2004). For an estimate of the geochemical background, 30 unaffected soils near the edge of the spill were also analysed at the same depths. The soils were contaminated before the spill and, the accident seriously increased the concentration of As and Zn in the first 10 cm of almost all the affected soils. After the enormous efforts of cleaning up the tailings, around 45% of the soils had a concentration higher than 100 mg As kg⁻¹ dry soil, and some 35% had a concentration higher than 1,000 mg Zn kg⁻¹ dry soil. Both As and Zn penetrated between 10 and 30 cm in 25% and 45% of the soils, respectively, but reached 30 cm in only 12% of the soils. The remediation actions, especially the tilling and homogenisation of the uppermost 25 cm of the all soils, caused the As and Zn concentrations to decline in the soils, but this change was not very effective from the standpoint of pollution. Thus, 6 years after the spill, the uppermost 10 cm of 30% of the soils continued to have an As concentration higher than 100 mg As kg⁻¹, while the Zn concentration diminished considerably on the surface due to its greater mobility, accumulating between 10 and 30 cm in depth, where 20% of the soils continued to register more than 1,000 mg Zn kg⁻¹ dry soil.

This study examines the relationship between dissolved inorganic nitrogen (DIN: NH₄ ⁺ + NO₂ ⁻ + NO₃ ⁻) and dissolved organic nitrogen (DON) in river water and groundwater in an agriculturally-dominated catchment in south-east Spain, and estimates the contribution of DON to the total dissolved nitrogen (TDN) concentrations. The studied aquifer-dependent river system consists of Quaternary alluvial sediments deposited by the Guadalquivir River and its tributaries, with both river water and groundwater in the catchment being aerobic. DON is the predominant form of nitrogen in river water (72-97% of the TDN), whereas its proportion to TDN varies considerably in groundwater (<1-99%). A seasonal pattern in the concentration of dissolved nitrate in river water was observed, whereas DON concentrations showed no significant change during the study period. The export of DON from the Guadalquivir River is approximately 2 kg N ha⁻¹ year⁻¹ and is an order of magnitude higher than the export of DON from pristine catchments. Dissolved nitrate concentrations in groundwater were slightly higher in winter and DON concentrations were significantly lower (p < 0.05) in summer. It is found that agricultural soils constitute the main storage of organic nitrogen in the catchment with a steady leaching of high DON concentrations into the alluvial aquifer system (mean value 19.1 mg N L⁻¹), and so indicating that DON should not be overlooked in the nitrogen budgets of agriculturally-dominated catchments.

The loss of pendimethalin, a selective herbicide, was determined in runoff water from loamy soil plots of various surface slopes cultivated with tobacco, over a period of 193 days. Conditions were selected to simulate agricultural practices employed in the Mediterranean region. The surface slopes of plots were 0%, 2.5%, 5%, 7.5%, and 10% and both cultivated and uncultivated (control) areas were simultaneously monitored. The cumulative losses of pendimethalin in surface runoff, as percentage of the initial applied active ingredient, were 0.067% for tilled and 0.098% for untilled soil of 10% slope, while for the plots of 0% slope they were ten times lower, 0.006% and 0.009% respectively. The maximum concentrations in runoff water reached 15.87 μg L⁻¹ and were detected after the second run off event. The dissipation in top soil was studied for a period of 129 days. The half-lives that were calculated using first order kinetics ranged from 23 to 27.2 days in non-cropped soil and from 22.3 to 26.2 in tobacco plots.

Sampling was conducted at seven sites on, and at varying distances adjacent to, the Island of Montréal (Québec, Canada), and as far as 1,100 km away in Northern Québec, to explore the hazard potential of snowpacks in remote, rural, and urban environments. Ecotoxic effects of melted snow were ascertained with a suite of small-scale bioassays representing several aquatic taxonomic groups (bacteria, micro-algae, micro-invertebrates, fish liver cells) as well as with biomarker measurements determined with a rainbow trout primary hepatocyte (RTPH) assay. Bioassays undertaken with the cnidarian Hydra attenuata and RTPH cell assays, and to a lesser extent with the micro-alga Pseudokirchneriella subcapitata, proved particularly sensitive to infer the presence of bio-available pollutants in snow samples collected from all sites, thereby suggesting their contamination (at least) via atmospheric sources. Furthermore, biomarker responses indicated that snow samples presumably included metals (free Zn biomarker), organics (CYP 1A1 biomarker), estrogens (alkali-labile phosphate biomarker) as well as chemicals capable of causing oxidative stress (LPO biomarker), depending on the site being considered. Overall, effects data acquired during this preliminary investigation on the ecotoxicity of snowpacks submit that adverse impact toward aquatic biota is conceivable at some sites during spring meltdown. Because snow has a recognized affinity for sequestering solids and contaminants of atmospheric origin, future studies aimed at identifying sources and chemicals implicated in observed effects are legitimate endeavors.

Municipal solid waste (MSW) source-classified collection represents an advancement in resource recycling and secondary pollution control in China. Comparative experiments were performed to assess the effect of a newly-established MSW source-classified collection system on polycyclic aromatic hydrocarbons (PAHs) in bottom ash from an incinerator (BA), fly ash from a boiler (FAB) and fly ash from a bag filter (FABF) of a full-scale MSW incinerator in China. Compared with FAB or FABF, PAHs were mainly concentrated in BA with a range of 1,961.0-2,420.2 μg/kg. Total amounts of 16 high priority PAHs in BA, FAB and FABF from the classified MSW incineration were significantly reduced by 19.0%, 42.4% and 59.8% respectively in comparison with those from the traditional mixed MSW incineration. Moreover, the toxic equivalent quantity (B[a]Peq) of carcinogenic PAHs in these three kinds of residues from the classified MSW incineration were significantly decreased, with the maximum decrease observed in FABF. As a result of source-classification with effective presorting and dewatering, plastics and metals in the MSW were lower, but combustibles and heat values of the MSW increased. Due to variations of the characteristics of the feed waste, complete combustion conditions including continuous higher incineration temperature, lower CO concentration and higher air excess ratio were observed during the process of classified MSW incineration. Incineration temperature and CO concentration showed a negative and positive correlation, respectively, with total PAHs, indicating that incomplete combustion products such as PAHs could be reduced by controlling combustion conditions directly related to properties of the feed waste. The newly established MSW source-classified collection process could be a feasible method for reducing PAHs formation and emission in residues from MSW incineration.

In order to study the potential use of microfauna as an indicator of effluent quality and operational parameters in an activated sludge system for treating piggery wastewater, an experimental sequencing batch reactor was set up and evaluated by biological and physical-chemical analyses for 12 months. Results show that microfauna (and specifically ciliate protozoa) are a good parameter for assessing effluent quality in terms of both chemical oxygen demand (COD) and ammonia and for assessing the organic and nitrogen load of the system. Specifically, the abundance of ciliates decreases from 20,000 individuals·mL⁻¹ to ca. 2,500 individuals·mL⁻¹ and from ca. 10,000 individuals mL⁻¹ to ca. 200 individuals mL⁻¹ when effluent concentration is between 550 and 750 mg L⁻¹ and above 100 mg L⁻¹ to the COD and ammonia concentrations, respectively. Furthermore, microfauna abundance is reduced from ca. 18,000 individuals mL⁻¹ (organic load between 0.1 and 0.2 mg COD mg total suspended solids (TSS)⁻¹ day⁻¹) to ca. 500 individuals mL⁻¹ (organic load between 0.3 and 04 mg COD mg TSS⁻¹ day⁻¹). Microfauna abundance also decreases as nitrogen loading increases. Nitrogen loading in the range of 5-60 mg NH₄-N g TSS⁻¹ day⁻¹ does not have any significant effect on microfauna abundance. However, ammonia loading from 60 to 120 mg NH₄-N g TSS⁻¹ day⁻¹ reduces microfauna abundance ca. 6-fold. Ciliate protozoa were the largest microfauna group during the whole period of study, representing ca. 75% of the total microfauna abundance. The largest group in the ciliate community was that of the free-swimming ciliates. This was followed by the group of attached and crawling ciliates. Specifically, the dominant ciliate species during the whole study period were Uronema nigricans, Vorticella microstoma-complex, Epistylis coronata, and Acineria uncinata.

The unsaturated zone of an aquifer serves as a water reservoir which discharges water and eventual pollution to the saturated zone for a relatively long period after the cessation of surface input. Effective protection of a water resource requires detailed knowledge of transport mechanisms through the unsaturated zone with regard to its protective function. The article presents the application of isotope methods in the study of groundwater transport processes in the unsaturated zone of Selniška Dobrava coarse gravel aquifer. Emphasis is given to the use of environmental isotopes as natural tracers in the study of groundwater dynamics in the unsaturated zone. The estimation of groundwater flow characteristics was based on experimental work in lysimeter. Based on long-time isotope investigations with the use of lumped parameter models, some water flow parameters (mean residence time, mean matrix flow velocity) in the unsaturated zone were calculated. The results were compared with tracing experiment results in the same lysimeter.