Although the climate change effects on plants have been a focus for more than two decades, such effects on aquatic species remain largely unknown. To evaluate the potential effects of elevated CO₂ on growth and nutrient uptake of Eichhornia crassipe Solms (commonly known as water hyacinth, the world's most significant invasive aquatic weed), plants were grown at two CO₂ concentrations (380 and 800 ppm) combined with four nutrient levels (oligo-, meso-, eu-, and hypertrophic) for 2 months. Overall, elevated CO₂ consistently enhanced plant growth at all nutrient levels, indicating more infestations of water hyacinth in future natural eutrophic waters. Moreover, the enhancement extent varied among nutrient availabilities, being more in eu- and hypertrophic levels and less in meso- and oligotrophic levels. Furthermore, the CO₂ enrichment-deduced assimilation was allocated more to plant roots than shoots which would improve the nutrient absorption capacity and mostly transferred to offspring ramets rather than maintained at the mother ramet which would benefit the vegetative reproduction. Finally, under elevated CO₂, although the nitrogen (N) and phosphorus (P) contents of E. crassipe slightly decreased which might mean increased difficulties in preventing its infestation by reducing N and/or P in eutrophic waters, the total N and P accumulation increased suggesting higher bioremediation efficiency of using water hyacinth for water eutrophication.

Restoration of riparian buffers is an important component of nutrient reduction strategies in the Chesapeake Bay watershed. In 1998, Maryland adopted a Conservation Reserve Enhancement Program (CREP), which provides financial incentives to take agricultural land out of production to plant streamside vegetation. Between 1998 and 2005, 1-30% of streamside vegetation (average = 11%), was restored to forest or managed grass in 15 agriculturally dominated sub-basins in the Choptank River basin, a tributary of Chesapeake Bay. Pre-existing forested buffers represented 10-48% of the streamside (average = 33%), for a total of 12-61% buffered streamsides (average = 44%). Using multi-year water quality data collected before and after CREP implementation (1986, 2003-2006), we were unable to detect significant effects of CREP on baseflow nutrient concentrations based on the area of restored buffer, the percentage of restored streamside, or the percentage of total riparian buffer in the sub-basins (p > 0.05). Although CREP increased the average buffered streamside from 33% in the 1990s to 44% by 2005, N and P concentrations have not changed or have increased in some streams over the last 20 years. Reductions may not have occurred for the following reasons: (1) buffer age, width, and connectivity (gaps) between buffers are also important to nutrient reductions; (2) agricultural nutrient inputs may have increased during this period; and (3) riparian buffer restoration was not extensive enough by 2005 to have measurable affects on the stream water quality in these sub-basins. Significant effects of CREP may yet be resolved as the current CREP buffers mature; however, water quality data through 2006 in the Choptank basin do not yet show any significant effects.

Photocatalytic activity in titanium dioxide (TiO₂) has been extensively studied because of its potential use in sterilization, sanitation, and remediation applications. The aim of the study reported here was to assess the feasibility of “fixed” TiO₂ as the photocatalyst for inactivating pathogenic bacteria selected, Staphylococcus aureus and Escherichia coli, from a water stream. The investigation was undergone in a properly designed laboratory-scale evaluation. Using the system reported here, we obtained an effective bactericidal capability for E. coli and S. aureus with 90.0% and 98.0% after 30 and 10 min ultraviolet-A light irradiation with fixed TiO₂, respectively. Parameters such as the various initial bacteria concentration, TiO₂ concentrations, interruption of illumination, turbidity, and coexisted organic matters were examined to identify the removal efficiency in the photocatalytic reaction. Results indicated the negative effect by high bacteria concentration, coexisted organic matters, and turbidity on inactivation of bacteria, and positive effect on disinfection was associated with higher TiO₂ concentration. Furthermore, our results indicated that under the same experimental conditions, the removal efficiency of the system in synthetic water was performed better than that of crude water. This inferior removal capability in crude water is mainly caused by the negative effect from the unknown coexisted factors.

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.

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.

Exposure to micropollutants can pose a serious risk to both the environment and human health. Although sewage treatment works (STWs) aim to reduce levels of pollutants in municipal wastewater discharges, they have become a significant point source of dangerous substances to the aquatic environment. With increasing regulation on pollution prevention, it has become essential to assess STW source inputs in order to control pollutant discharge into the environment. This paper has therefore focussed on developing calculations to estimate micropollutant levels in STW influents. The analysis was carried out using information from published literature, the Water Industry, and monitored influent data. Results demonstrated that, where monitoring data were available for metals and organic pollutants, STW influent could be adequately estimated and validated, with accuracy between 77% and 100%. In addition, based on these calculations and using data for over 600 STWs in England, our analysis showed that compounds such as di(2-ethylhexyl) phthalate, lead and linear alkylbenzenesulfonate could reach influent levels that could be challenging for conventional wastewater treatment removal.

The Han River, which is the largest river in Korea, is the primary source of drinking water for the 20 million people that live in the Seoul metropolitan and surrounding areas. The sediments in the river are highly polluted due to pollutant inputs from upstream tributaries as well as from partially treated municipal wastewaters. To characterize the contamination of the sediments, disturbed and undisturbed sediment samples were periodically collected from eight locations of the mid-to-lower Han River. They were analyzed for pH, water content, total solids, ignition loss (IL), total phosphorous (TP), total Kjehldahl nitrogen (TKN), and chemical oxygen demand (COD). The mean values of pollutant concentrations in disturbed sediment were determined to be 6.9% for IL, 1,700 mg/kg for TP, 3,350 mg/kg for TKN, and 65,710 mg/kg for COD. Pollutant concentrations of undisturbed samples were found to decrease with sediment depth and time due to the removal mechanism. Monitoring of pre- and post-dredging conditions was also performed, and the results show that the pollutant concentrations decreased from those for the pre-dredging condition to 33-57% for TP, 51-64% for TKN, and 30-62% for COD. It is concluded that dredging was an effective means to reduce the internal pollutant source.

Diplopods feed organic matter in decomposition; however, some environmental factors can promote changes in tissues of these animals. Sewage sludge has been applied for recuperation of physical structure of degraded soil. This work analyzed the influence of the sludge from a city of São Paulo in the midgut of the diplopod Rhinocricus padbergi. After the exposition to sludge, the midgut was prepared for histological and ultra-structural analyses. After 1 week of exposition, there were various glycoprotein globules in the fat body, which appeared, ultrastructurally, little electron dense. In the animals exposed for 2 weeks, there was an intensive renovation of the epithelium with the invasion of regenerative cells, which was observed in the histological and ultra-structural analyses. These data showed that the sludge present various substances that were very hazardous for these animals; more studies were necessary before the application of this in agriculture.

Tamarind fruit shell was used as a low-cost biosorbent for the removal of methylene blue from aqueous solution. The various factors affecting adsorption, such as agitation, pH, initial dye concentration, contact time, and temperature, were investigated. The dye adsorption capacity was strongly dependent on solution pH as well as temperature. The Langmuir isotherm model showed good fit to the equilibrium adsorption data, and the maximum adsorption capacity obtained was 1.72 mg g⁻¹ at 303 K. The kinetics of adsorption followed the pseudo-second-order model and the rate constant increased with increase in temperature, indicating endothermic nature of adsorption. The Arrhenius equation was used to obtain the activation energy (E a) for the adsorption system. The activation energy was estimated to be 19.65 kJ mol⁻¹. Thermodynamic parameters such as Gibbs free energy (ΔG ⁰), enthalpy (ΔH ⁰), and entropy (ΔS ⁰) were also investigated. Results suggested that adsorption of methylene blue onto tamarind fruit shell was a spontaneous and endothermic process. The present investigation suggests that tamarind fruit shell may be utilized as a low-cost adsorbent for methylene blue removal from aqueous solution.