The potential ecological hazard of metals in soils may be measured directly using a combination of chemical and biological techniques or estimated using appropriate ecological models. Terrestrial ecotoxicity testing has gained scientific credibility and growing regulatory interest; however, toxicity of metals has often been tested in freshly amended soils. Such an approach may lead to derivation of erroneous toxicity values (EC₅₀) and thresholds. In this study, the impact of metal amendments on soil ecotoxicity testing within a context of ion competition was investigated. Four coarse-textured soils were amended with copper (Cu) and nickel (Ni), incubated for 16 weeks and conditioned by a series of total pore water replacements. RhizonTM extracted pore water Cu, Ni, pH and dissolved organic carbon (DOC) concentrations were measured after each replacement. Changes in ecotoxicity of soil solutions were also monitored using a lux-based biosensor (Escherichia coli HB101 pUCD607) and linked to variations in soil solution metal and DOC concentrations, pH and selected characteristics of the experimental soils (exchangeable calcium (Ca) and magnesium (Mg)). Prior to conditioning of soils, strong proton competition produced relatively high EC₅₀ values (low toxicity) for both, Cu and Ni. The successive replacement of pore waters lead to a decline of labile pools of metals, DOC and alleviated the ecotoxicological protective effect of amendment impacted soil solution chemistry. Consequently, derived ecotoxicity values and toxicity thresholds were more reflective of genuine environmental conditions and the relationships observed more consistent with trends reported in historically contaminated soils.

Chemical mass balance (CMB) and principal component analysis (PCA) are used together for source identification and source apportionment in this air pollution modeling study. Source profile sets, each of which contains five source profiles based on ten pollutant species, were generated using a computer program. Another algorithm was implemented to produce ten random data sets, which was composed of 100 simulated measurement results for all of ten pollutant species. Ten source profile sets were selected. Five of them contained sources of dissimilar characteristics, whereas the other five were chosen from those of similar emission profiles. Ten simulated data sets for each source profile set were used in the analyses. PCA was applied to all simulated data sets; a number of principal factors were extracted and interpreted. The identified sources for each data set were used in fitting with CMB analyses, and source contributions were estimated. The performance of PCA-CMB combination was evaluated in the aspect of percent variance explained, percent apportionment, R ², and χ ². PCA was able to explain 89.6% to 100% of the variance within the data sets used. Two to five sources were extracted depending on the characteristics of source profile sets used. CMB was found to be successful in the aspect of percent apportionment since 95.4% to 100% of mass concentrations were apportioned. The values of R ² and χ ² were found out to range from 0.981 to 1.000 and from 0.000 to 29.947, respectively. Evaluating overall results from the analyses, PCA-CMB combination produced satisfactory results in the aspect of source identification and source apportionment.

Biological treatment systems such as biofilters offer a potential alternative to the existing physicochemical techniques for the removal of volatile organic compounds from gaseous emissions. In this experimental work, continuous phase biofiltration of xylene vapors were performed in a laboratory scale compost biofilter that was inoculated with a xylene-acclimatized consortium. The performance was assessed by continuously monitoring the removal efficiency (RE) and elimination capacity (EC) of the biofilter at loading rates varying between 2-220 g m⁻³ h⁻¹. The steady-state removal efficiencies were maintained between 60% and 90% up to a loading rate of 80 g m⁻³ h⁻¹. The removal efficiency decreased significantly at loading rates higher than 100 g m⁻³ h⁻¹. The pressure drop values were consistently less and insignificant in affecting the performance of the system. The present study also focuses in evaluating the stability of biofilter during shut down, restart, and shock-loading operations. An immediate restoration of biological activity after few days of starvation indicated their capability to handle discontinuous treatment situations which is more common to industrial biofilters. The sensitiveness of the biofilm to withstand shock loads was tested by abruptly increasing/decreasing the loading rates between 9-55 g m⁻³ h⁻¹, where, removal efficiencies between 60-90% were achieved. These results prove the resilience of the biomass and the stability of the compost biofilter. Anew, results from kinetic analysis reveal that, steady-state xylene removal in the biofilter can be adequately represented by Michaelis-Menten type kinetics, and the kinetic constants namely, ECmax (120.4 g m⁻³ h⁻¹) and K s (2.21 g m⁻³) were obtained.

Despite many efforts for pollution abatement in aquatic ecosystems, there are still some cases of high accumulation of industrial pollutants due to past activities. In Flix reservoir (Ebro River, Spain), there are around 200,000-360,000 tons of industrial pollutants with a high concentration of heavy metals and organochlorides due to the activity of an organochlorine industry during more than half a century. This exceptional amount of pollutants provides a good opportunity (and need) to analyse their effects on fish populations under natural conditions, which is rarely available to ecotoxicologists. We compared the reproductive traits and prevalence of diseases and parasites at this impacted area with a neighbouring upstream reservoir unaffected by the pollution (reference sites) and also to downstream sites. Deformity, eroded fin, lesion and tumour (DELT) anomalies and ectoparasites were clearly more frequent at the impacted area for several fish species (common carp, roach and pumpkinseed). A significant negative impact of Flix reservoir on condition (eviscerated and liver weights, adjusted for fish size with analysis of covariance) and reproductive traits (gonadal weight and number of mature eggs, adjusted for fish size) was also detected for several fish species. The responses to the pollutants were species-specific, and common carp (Cyprinus carpio) was the species with the clearest effects on fitness-related traits at the impacted area, despite also being among the most tolerant to pollution.

Water quality trends from 1970 to 2005 were defined along 30 Delaware streams in the Delaware and Chesapeake Bay watersheds in the USA. Water quality improved or was constant at 69% of stations since 1990 and at 80% of stations since 1970/1980. Dissolved oxygen (DO) improved or was constant at 73% of streams since 1990 and 32% of streams since 1970/1980. Total suspended sediment improved or was constant at 75% of streams since 1990 and 100% of streams since 1970/1980. Enterococcus bacteria improved or remained constant at 80% of streams since 1990 and 93% of streams since 1970/1980. Total Kjeldahl nitrogen improved or was constant at 48% of streams since 1990 and 100% of streams since 1970/1980. Total phosphorus improved or was constant at 66% of streams since 1990 and 85% of streams since 1970/1980. During 2001-2005, median levels were good or fair at 100% of the stations for DO, 78% for sediment, 50% for bacteria, 59% for nitrogen, and 56% for phosphorus. Good water quality correlates with high amounts of forest area (>25%) in Delaware watersheds. Since the Federal Clean Water Act Amendments of the 1970s, improving Delaware water quality stations (50) outnumbered degrading stations (23) by a 2:1 margin. Since 1990, degrading water quality stations (46) exceeded improving stations (38) mostly due to deteriorating nitrogen levels in half of Delaware streams, a reversal from early gains achieved since the 1970s. Over the last three and a half decades, watershed strategies have improved or preserved water quality along Delaware streams; however, greater emphasis is needed to curb recently resurging increases in nitrogen levels.

The potential of domestic wastewater treatment plants to contribute for the dissemination of ciprofloxacin-resistant bacteria was assessed. Differences on bacterial counts and percentage of resistance in the raw wastewater could not be explained on basis of the size of the plant or demographic characteristics of population served. In contrast, the treated effluent of the larger plants had significantly more heterotrophs and enterobacteria, including ciprofloxacin-resistant organisms, than the smaller (p < 0.01). Moreover, longer hydraulic retention times were associated with significantly higher percentages of resistant enterobacteria in the treated effluent (p < 0.05). Independently of the size or type of treatment used, domestic wastewater treatment plants discharged per day at least 10¹⁰-10¹⁴ colony forming units of ciprofloxacin-resistant bacteria into the receiving environment.

The concentration and size distribution of bacterial and fungal aerosol was studied in 15 houses. The houses were categorized into three types, based on occupant density and number of rooms: single room in shared accommodation (type I), single bedroom flat in three storey buildings (type II) and two or three bedroomed houses (type III). Sampling was undertaken with an Anderson six-stage impactor during the summer of 2007 in the living rooms of all the residential settings. The maximum mean geometric concentration of bacterial (5,036 CFU/m³, ± 2.5, n = 5) and fungal (2,124 CFU/m³, ± 1.38, n = 5) aerosol were in housing type III. The minimum levels of indoor culturable bacteria (1,557 CFU/m³, ±1.5, n = 5) and fungal (925 CFU/m³, ±2.9, n = 5) spores were observed in housing type I. The differences in terms of total bacterial and fungal concentration were less obvious between housing types I and II as compared to type III. With reference to size distribution, the dominant stages for culturable bacteria in housing types I, II and III were stage 3 (3.3-4.7 μm), stage 1 (7 μm and above) and stage 5 (1.1-2.1 μm), respectively. Whereas the maximum numbers of culturable fungal spores were recovered from stage 2 (4.7-7 µm), in housing type I, and from stage 4 (2.1-3.3 μm) in both type II and III houses. The average geometric mean diameter of bacterial aerosol was largest in type I (4.7 μm), followed by type II (3.89 μm) and III (1.96 μm). Similarly, for fungal spores, type I houses had the highest average mean geometric diameter (4.5 μm), while in types II and III the mean geometric diameter was 3.57 and 3.92 μm, respectively. The results indicate a wide variation in total concentration and size of bioaerosols among different residential settings. The observed differences in the size distributions and concentrations reflect their variable airborne behaviour and, as a result, different risks of respiratory exposure of the occupants to bioaerosols in various residential settings.

The present study focused on the degradation of mixed pesticides using UV-induced photocatalytic degradation of lindane (1α,2α,3β,4α,5α,6β-hexachlorocyclohexane), methyl parathion (O,O-dimethyl-O-4-nitrophenyl phosphorothioate), and dichlorvos (2,2-dichlorovinyl-O-O-dimethyl phosphate). Different grades of TiO₂ were prepared through the acid route (AR), alcohol route (AlR), and surfactant route (SR) and their photocatalytic activity were compared with commercially available Degussa P-25 TiO₂. The rate of degradation of pesticides was high for TiO₂ prepared through the SR compared to the other three catalysts. The crystalline structure and morphology of SR TiO₂ was identified with scanning electron microscope, energy dispersive X-ray analyzer, UV, and transmission electron microscope analyses and was compared with that of Degussa P-25 TiO₂. Degradation studies of individual as well as mixed pesticides were carried out. The intermediate formed during the photodegradation of methyl parathion, lindane, and dichlorvos were identified by gas chromatography-mass spectrometry analysis.

Ganga-Meghna-Bramhaputra basin is one of the major arsenic-contaminated hotspot in the world. To assess the level of severity of arsenic contamination, concentrations of arsenic in irrigation water, soil, rice, wheat, common vegetables, and pulses, intensively cultivated and consumed by the people of highly arsenic affected Nadia district, West Bengal, India, were investigated. Results revealed that the arsenic-contaminated irrigation water (0.318-0.643 mg l⁻¹) and soil (5.70-9.71 mg kg⁻¹) considerably influenced in the accumulation of arsenic in rice, pulses, and vegetables in the study area. Arsenic concentrations of irrigation water samples were many folds higher than the WHO recommended permissible limit for drinking water (0.01 mg l⁻¹) and FAO permissible limit for irrigation water (0.10 mg l⁻¹). But, the levels of arsenic in soil were lower than the reported global average of 10.0 mg kg⁻¹ and was much below the EU recommended maximum acceptable limit for agricultural soil (20.0 mg kg⁻¹). The total arsenic concentrations in the studied samples ranged from <0.0003 to 1.02 mg kg⁻¹. The highest and lowest mean arsenic concentrations (milligrams per kilogram) were found in potato (0.654) and in turmeric (0.003), respectively. Higher mean arsenic concentrations (milligrams per kilogram) were observed in Boro rice grain (0.451), arum (0.407), amaranth (0.372), radish (0.344), Aman rice grain (0.334), lady's finger (0.301), cauliflower (0.293), and Brinjal (0.279). Apart from a few potato samples, arsenic concentrations in the studied crop samples, including rice grain samples were found not to exceed the food hygiene concentration limit (1.0 mg kg⁻¹). Thus, the present study reveals that rice, wheat, vegetables, and pulses grown in the study area are safe for consumption, for now. But, the arsenic accumulation in the crops should be monitored periodically as the level of arsenic toxicity in the study area is increasing day by day.

The degradation of diethyl phthalate (DEP) in aqueous solution by titanium dioxide (TiO2) photocatalysis has been investigated in our research. DEP was completely removed in the solution by 50-min irradiation. Results show that DEP degradation rate was affected by initial DEP concentration, photocatalyst amount, light intensity, and pH. Photocatalytic degradation intermediates were identified by gas chromatography-mass spectrometry intermediates were identified by gas chromatography-mass spectrometry. The major intermediates are methyl benzoate, ethyl benzoate, and carboxylic derivatives. The photocatalytic degradation process was found to obey first-order reaction. Consequently, the result of photocatalytic degradation could be an efficient method of DEP removal from wastewater.