Sulphuric acid-modified bagasse has been used as low-cost adsorbent for the removal of methylene blue (MB) dye from aqueous solution. In order to remove organic compounds that contribute to chemical oxygen demand (COD), pretreatment with thorough washing of adsorbent using boiling distilled water was performed instead of conventional washing using distilled water at room temperature only. This has resulted in the highest efficiency of color removal of 99.45% and COD reduction of 99.36% for MB dye solution at pH 9. Effects of initial pH, dye concentration, adsorbent dosage, temperature, and contact time have been studied. The adsorption of MB dye was pH dependent. Langmuir and Freundlich isotherm models were tested on the adsorption data. The kinetic experimental data were analyzed using pseudo-first order, pseudo-second order, and the intraparticle diffusion model in order to examine the adsorption mechanisms. The adsorption process followed the Langmuir isotherm as well as the Freundlich isotherm and pseudo-second-order kinetic model. The process was found to be endothermic in nature.

Among the most extensively used compounds for the pest control in Argentinean crops is the organochlorine endosulfan. The sublethal effects of the commercial endosulfan formulation on hematology and lipid peroxidation (LPO) of the neotropical fish Prochilodus lineatus were investigated. Firstly, we calculated acute toxicity (LC50) in order to define sublethal concentrations (0, 1.2, and 2.4 μg L−1). Hematological and oxidative stress responses were assessed at 24, 48, and 96 h. Endosulfan exposure significantly diminished the hemoglobin concentration, mean cell hemoglobin, and total plasma protein and increased white blood cells count and plasma glucose after 96 h. Exposed fish showed an alteration of the differential leukocytes count, evidenced by more thrombocytes and monocytes and less lymphocytes and neutrophils. Endosulfan increased LPO levels in intestine, liver, and brain in both sublethal concentrations. The present results suggest that endosulfan produces biochemical and physiological alterations, including immunological disorders, and it is a good inductor of oxidative stress in P. lineatus.

Surface coastal sediments (0–10 cm) collected from three natural environments on the Spanish Northern Atlantic Coast were analyzed so as to determine concentrations of 6 marker polychlorinated biphenyls (PCBs), 12 dioxin-like PCBs (dl-PCBs) and 17 polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). An analytical procedure based on Soxhlet extraction followed by an automated cleanup and final high-resolution gas chromatography coupled to high-resolution mass spectrometry was applied for the determination of the persistent organic pollutants. Marker PCB levels ranged from 385.5 to 4,060.9 pg/g dry weight (d.w.) showing a similar congener pattern in all sediments dominated by the less volatile congeners PCB 153 and PCB 138. Linear correlations were found between marker and dl-PCBs. Toxicity equivalent values were calculated for PCDD/Fs and dl-PCBs reaching its maximum at 0.52 pg WHO1998-TEQ/g d.w., with an average dl-PCBs contribution on the toxicity of the samples of 75%, and showing to be in good agreement with background levels in the North-East Atlantic Ocean Coasts of nearly 1 pg/g WHO1998-TEQ d.w. Dimensionless environmental quality criteria were much lower than 1 indicating the low probability to induce ecotoxicological impacts.

In the present investigation, treatment of metal cutting wastewater (MCW) using electrocoagulation (EC) process is designed and analyzed using response surface methodology (RSM). RSM is applied to optimize the operating variables viz. initial pH, current density, and operating time on the treatment of MCW in a batch mode by EC process using iron and aluminum electrodes. Quadratic models are developed for the responses such as chemical oxygen demand (COD), total organic carbon (TOC), and turbidity, and operating cost is calculated with respect to energy, electrode, and chemical consumptions. The actual COD, TOC, and turbidity removal efficiencies at optimized conditions are found to be 93.0%, 83.0%, and 99.8% for Fe electrode and 93.5%, 85.2%, and 99.9% for Al electrode, respectively, which agree well with the predicted response. The proposed model fits very well with the experimental data with R 2 adjusted correlation coefficients of 0.927 for COD, 0.924 for TOC, and 0.968 for turbidity removal for Al and 0.904 for COD, 0.976 for TOC, and 0.989 for turbidity removal for Fe electrodes, respectively. This study clearly shows that RSM is one of the suitable methods to optimize the operating conditions and maximize the COD, TOC, and turbidity removal efficiencies for both electrodes while keeping the operating costs to minimal (0.371 <euro>/m3 for Fe and 0.337 <euro>/m3 for Al electrodes).

In order to evaluate fixation potential of schwertmannite for fluvial transport of various toxic elements, we examined bottom precipitates and stream waters collected from the rivers contaminated with acid mine drainage (AMD), which arose from the abandoned Nishinomaki mine (Shimonita, Gunma, Japan). Mineralogical and morphological observations revealed that schwertmannite was the main mineral of the precipitates. The affinity of various toxic ions to schwertmannite was evaluated on the basis of (1) apparent solid–liquid partition coefficients (K d’s) between precipitates and stream waters, (2) coprecipitation behaviors during schwertmannite formation in a laboratory test, and (3) consideration on coprecipitation processes using partial charge model (PCM). As a result, oxyanions of V, As, Mo and Sb, K d’s of which were relatively large (>104 (ml g−1)), were considered to be immobilized by schwertmannite precipitates. A laboratory test also demonstrated that these ions except Mo coprecipitated with schwertmannite. In addition, partial charges and average electronegativities predicted on the basis of PCM suggested that the oxyanions of V, As, Mo, and Sb could create stable inner sphere complexes with schwertmannite embryos, which results in their high affinity to schwertmannite. On the other hand, cationic ions of Mn, Cu, Zn, Sr, Cs, and U, K d’s of which were relatively small (<104 (ml g−1)), were thought to have a tendency to flow downstream without uptake by schwertmannite precipitates. All these results suggested that schwertmannite has high fixation potential for fluvial transport of various toxic oxyanions in AMD-contaminated rivers.

Two commercially available aerobic bioremediation methods (Daramend® and BioSan) were utilized to study the aerobic biodegradation of polycyclic aromatic hydrocarbons (PAH) and the effect of the simultaneously present arsenic. The soil was collected at an old wood preservation site, and the initial PAH₁₆-concentration was 46 mg/kg, with mainly high molecular weight congeners. The As concentration was 105 mg/kg with low availability as assessed with sequential extraction. To enhance the availability of PAH, the effect of a nonionic surfactant was evaluated. Degradation of both low and high molecular weight PAH was observed; however, after 30 weeks, the degradation was generally low and no treatment was significantly better than the others. The treatments had, on the other hand, an effect on As remobilization, with increased As concentration in the available fraction after treatment. This may be due to both the microbial activity and the presence of anoxic microsites in the soil. The overall efficiency of the biological treatment was further evaluated using the standardized ecotoxicity test utilizing Vibrio fischeri (Microtox®). The toxicity test demonstrated that the bioremediation led to an increase in toxicity, especially in treatments receiving surfactant. The surfactant implied an increase in contaminant availability but also a decrease in surface tension, which might have contributed to the overall toxicity increase.

Diplopods are components of the edaphic fauna, which makes them suitable bioindicators of soil quality. Some characteristics of the fat body of diplopods make it suitable for ecotoxicological studies. This organ, composed of diffuse tissue, fills the body cavity; it presents intense metabolic activity associated with lipid, glycogen, protein, and uric acid storage, being also responsible for storage, neutralization, and excretion of substances that are not useful to the organism. The present study aimed to investigate whether the perivisceral fat body of Rhinocricus padbergi can be used as a target organ in ecotoxicological studies and to identify possible histological and histochemical biomarkers in this organ. Upon examining the perivisceral fat body of individuals of R. padbergi exposed to different concentrations of industrial soil contaminated with polycyclic aromatic hydrocarbons (∑ 2,749.0 mg/kg) and metals (∑ 40,355.8 mg/kg), we have found evidence that this organ is sensitive to environmental pollutants present in the soil. The loss of integrity of the cell boundary associated with cytoplasmatic disorganization and depletion in total proteins, neutral polysaccharides, calcium, and lipids can be considered stress biomarkers for R. padbergi.

Air quality levels vary over regions due to meteorological factors, proximity to sources, and local conditions (i.e., topography). The Northeast USA is subjected to pollution inputs from both local sources and those from the upwind Midwest USA that are transported by prevailing meteorological patterns. With the passage of the Clean Air Act in 1970 and the establishment of the National Ambient Air Quality Standards (NAAQS), national levels of air pollutants have declined significantly. Our study compared air quality time trends between five of the largest cities within New York State (Albany, Buffalo, New York City, Rochester, and Syracuse) and statewide means to national trends. Data were obtained from the NYS Department of Environmental Conservation (DEC) Bureau of Air Quality Surveillance for six criteria pollutants: carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), particulate matter (PM₂.₅), and lead (Pb). Regional Kendall tests found significant downward trends for each pollutant statewide from 1980 to 2007, while trends by city varied by decade and pollutant. The evaluation of historical trends of pollution in industrialized nations is useful in showing recent air quality improvements and also in the understanding what can be the result in air pollutant controls in those developing nations currently experiencing high levels of pollution.

Eutrophication of surface water bodies is a worldwide concern. In the USA alone, excessive nutrients are blamed for nearly 5,700 impairments of surface water bodies. Innovative measures, such as maximizing drainage ditch nutrient retention, are being examined to decrease the amount of nitrogen (N) and phosphorus (P) running off agricultural lands and into aquatic receiving systems. The goal of this experiment was to measure the nutrient mitigation ability of six aquatic plants typically found in agricultural drainage ditches in the lower Mississippi River Basin. Experimental mesocosms (1.25 × 0.6 × 0.8 m) were filled with sediment and planted with monocultures of one of six obligate wetland plant species (Typha latifolia (broadleaf cattail), Panicum hemitomon (maidencane), Thalia dealbata (powdery alligator-flag), Echinodorus cordifolia (creeping burhead), Myriophyllum spicatum (Eurasian watermilfoil), and Saururus cernuus (lizard’s tail)), while three replicates were left non-vegetated to serve as controls. Mesocosms were amended with 5 mg L−1 (each) of nitrate, ammonia, dissolved inorganic phosphorus, and total inorganic phosphorus, while nitrite amendments (1 mg L−1) were also made over a 4-h hydraulic retention time. Following the 4-h exposure, “clean” (non-amended) water was flushed through mesocosms for an additional 8 h to assess residual leaching of nutrients. Outflow water concentrations and loads decreased for all examined forms of N and P. In certain cases, there were significant differences between plant species; however, for the majority, there was no statistical difference in percent decrease between plant species. While native aquatic vegetation shows promise for mitigation of nutrient runoff, further studies altering the hydraulic retention time for improved efficiency should be conducted.

In order to investigate the effects of canopy-dependent processes on throughfall chemistry, comparative studies on the chemical composition of throughfall were carried out in five characteristic forest types of the southeastern United States within Fort Benning Military Installation from January 2002 to August 2003. The concentrations and fluxes of and total organic carbon (TOC), total Kjeldahl nitrogen (TKN), and total phosphorus (TP) were determined in rainfall and throughfall. Seasonal variations in chemical fluxes were also evaluated. Throughfall concentrations of TOC, TKN, and TP in matured pine stand were higher than in rainfall and other forest stands. Throughfall nutrient concentrations in wetland were lowest as compared to rainfall as well as hardwood, mixed, plantation, and pine stands. The average TOC, TKN, and TP concentrations in the matured pine stand were 17.2, 0.74, and 0.057 mg/L, respectively. In wetland stands, average concentrations of TOC, TKN, and TP were 4.0, 0.54, and 0.034 mg/L, respectively. Hardwood stand had the lowest TKN concentration of 0.53 mg/L. Nutrient fluxes were generally higher during the dormant season (November–April) as compared to the growing season (May–October). The highest and lowest TOC fluxes during dormant season were contributed from pine stand (801.7 g/ha) and wetland stand (186.2 g/ha), respectively. Rainfall was the major contributor of TKN fluxes in growing season (32.3 g/ha) as well as in dormant season (34.1 g/ha). Similarly, highest TP flux was produced in mixed stand (2.7 g/ha) during the dormant season. Enrichment ratios of nutrients reveal that, in general, forest stands used up nutrients during growing season and washed off during the dormant season.