Energy intake and allocation are mainly used to maintain body functions, such as locomotion, growth, and reproductive output. It has been observed that environmental pollutants can affect the energy allocation either due to a cost of handling toxicants or because the toxicant interacts with the storage processes within the organisms. Less than a handful of studies are available reporting the effect of toxicants on energy reserves in enchytraeids and no studies have dealt with the influence of nanomaterials. The present paper shows results on the basal energy reserves (lipids, carbohydrates, and proteins) in Enchytraeus albidus and the influence of copper (Cu) salt and Cu nanoparticles on these reserves for two exposure durations. The energy allocation levels follow what has been reported for other worm species, although lower carbohydrate levels were observed. There were clear differences between worms exposed to control soils and those exposed to Cu for 3 weeks, but no difference after 6 weeks exposure. There was no apparent difference between the impacts of the two Cu exposure forms.

Selenium (Se) contamination of aquatic habitats is a global environmental issue. Although organic forms of Se are thought to represent the most bioavailable forms of Se, elevated concentrations of inorganic Se can cause toxicity in aquatic organisms such as benthic invertebrates. To assess the potential role of Se in mortalities observed during previous in situ invertebrate exposures, laboratory experiments on toxicity of inorganic Se (selenate) to Hyalella azteca were performed. Both a laboratory-reared and a field-collected H. azteca population were exposed to Se concentrations ranging from near 0 (control) to 21.79 mg/L, and survival of exposed individuals was monitored over 10 days. In the laboratory-reared H. azteca, significant changes in mortality pattern and reductions in mean survival time (MST) were noted in the test groups exposed to ≥0.164 mg/L Se. In the field-collected animals however, significant changes in mortality pattern and reductions in MST were measured in H. azteca exposed to ≥1.43 mg/L Se. The 10-day LC50s were 0.086 and 0.574 mg Se/L for the laboratory and field-collected H. azteca populations, respectively. The laboratory-reared group thus was about one order of magnitude more sensitive to Se exposure than the field-collected amphipods. Our results suggest that Se toxicity was likely not a major contributor to amphipod mortalities observed in earlier field studies. Furthermore, population-specific tolerances of the test organisms may need to be considered when extrapolating laboratory-generated data to field situations.

This study was carried out to examine the phytotoxicity and oxidant stress by CuO and ZnO nanoparticles (NPs) in Cumumis sativus and the characterization of CuO and ZnO NP suspensions. We estimated the bioaccumulation of CuO and ZnO NP in plant, reactive oxygen species enzyme (superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)) activities in plant tissue of root, and observed CuO and ZnO NPs with transmission electron microscopy. We found that the seedling biomass significantly decreased to 75% and 35% of that of control at 1,000 mg/L of CuO and ZnO NPs, respectively. The bioavailability and oxidant stress potential of plants exposed to metal oxide particles were dependent in the size, concentration, and species of the NPs. The median inhibition concentrations of CuO and ZnO NPs were 376 and 215 mg/L, respectively. In transmission electron microscopy, CuO and ZnO NPs greatly adhered to the root cell wall, and NPs were observed in the root cells. Another finding indicated that both CuO and ZnO NPs caused statistically significant increase in SOD, CAT, and POD activities and significant increase at 100 mg/L concentration levels. These results indicated that NPs alter both phytotoxicity and oxidative stress in plant assays. We further suggest that the oxidative stress markers appear to be a good predator of potential future toxicity of nanoparticles.

Plant growth-promoting rhizobacteria (PGPR) play an important role in the biodegradation of natural and xenobiotic organic compounds in soil. They can also alter heavy metal bioavailability and contribute to phytoremediation in the presence or absence of synthetic metal chelating agents. In this study, the inhibitory effect of Cd2+ and Ni2+ at different concentrations of Ca2+ and Mg2+, and the influence of the widely used chelator EDTA on growth of the PGPR Pseudomonas brassicacearum in a mineral salt medium with a mixture of four main plant exudates (glucose, fructose, citrate, succinate) was investigated. Therefore, the bacteriostatic effect of Cd2+, Ni2+ and EDTA on the maximum specific growth rate and the determination of EC50 values was used to quantify inhibitory impact. At high concentrations of Ca2+ (800 μmol L-1) and Mg2+ (1,250 μmol L-1), only a small inhibitory effect of Cd2+ and Ni2+ on growth of P. brassicacearum was observed (EC50 Cd2+, 18,849 ±â€‰80 μmol L−1; EC50 Ni2+, 3,578 ±â€‰1,002 μmol L−1). The inhibition was much greater at low concentrations of Ca2+ (25 μmol L−1) and Mg2+ (100 μmol L−1) (EC50 Cd2+, 85 ±â€‰0.5 μmol L−1 and EC Ni2+, 62 ±â€‰1.8 μmol L−1). For the chosen model system, a competitive effect of the ions Cd2+ and Ca2+ on the one hand and Ni2+ and Mg2+ on the other hand can be deduced. However, the toxicity of both, Cd2+ and Ni2+, could be significantly reduced by addition of EDTA, but if this chelating agent was added in stoichiometric excess to the cations, it also exhibited an inhibitory effect on growth of P. brassicacearum.

Over 5 days, Brassica juncea removed 54% of the highly toxic insecticide phorate from the medium with the formation of phorate sulfoxide in small quantity. The loss of phorate from the medium followed first-order kinetics. The half-life of phorate disappearance from water decreased by ~4.5-fold in the presence of B. juncea. Mild phorate phytotoxicity was evident from the elevated activities of the antioxidative enzymes like glutathione-disulfide reductase, glutathione S-transferase, superoxide dismutase, and catalase in the plants. Nevertheless, the ubiquitous antioxidative peroxidase was not significantly increased, nor the total glutathione content, due to phorate exposure. Phosphotriester bond hydrolysis and glutathione S-transferase-mediated conjugation seemed to be the key reactions for phorate metabolism by B. juncea. From the limited information available, for the first time, a tentative mapping of phytotransformation pathways was performed.

The aim of this study was to evaluate the use of metal concentrations in clam organs to monitor metal contamination in coastal sediments. The concentrations of Cd, Cr, Cu, Hg, Ni, Pb, V, and Zn were measured in the kidneys, gonads, mantles, gills, digestive gland, and hearts of the infaunal clam Amiantis umbonella collected from a contaminated site near desalination and power plant discharges, and a reference site in Kuwait Bay. Metal concentrations in sediment and sediment pore water were also measured at the collection sites of individual clams at the contaminated site. The concentrations of all metals in all organs (except Zn in the digestive gland) were significantly higher in clams from the contaminated site than from the reference site. Metal concentrations in several organs in A. umbonella from the contaminated site were correlated with those in the sediments and pore waters to which they were exposed. However, fresh weights of gonads, gills, and mantles were significantly lower in clams from the contaminated site compared to the reference site, indicating that the observed elevated concentrations of metals in the organs of clams from the contaminated site largely reflect lower organ weights, rather than higher metal loads, and that these organs in A. umbonella and perhaps other clams are not appropriate for use as biomonitors of metal contamination. Metal concentrations in clam kidneys showed a wide dynamic range with respect to environmental contamination and kidney weight was not variable. Therefore, metal concentrations in clam kidneys provide a reliable biomonitor of contaminant metals in coastal marine sediments.

Reclamation of land disturbed due to mining in arid and semiarid environments occurs across the globe. Large-scale surface mines provide unique opportunities to examine the reclamation process across a landscape. The objectives of this research were to (1) measure infiltration rates in reclaimed surface coal mines and (2) determine the effects of soil properties on ground cover on infiltration rates of surface coal mines. In this study, reclaimed land 10–15 and 20–25 years old, and native reference site (undisturbed) were investigated at two large surface coal mines in Wyoming, USA. Infiltration rates were measured using double-ring infiltrometer method. The soil properties including bulk density, pH, carbonate content, organic carbon content, aggregate stability, electrical conductivity, and soil texture were analyzed using standard methods. The ground cover was estimated visually. Statistical analysis was conducted to determine if any correlations between infiltration rate and soil properties and ground cover exist. Results suggest that at Mine 1, infiltration rates on reclaimed land were found to be significantly higher in the 20–25-year-old reclamation than the 10–15-year-old reclamation and the native site. At Mine 2, the native site had significantly higher infiltration than 20–25-year-old reclamation, which in turn had significantly higher infiltration rates than the 10–15-year-old reclaimed site. Along with infiltration, soil characteristics were examined. Overall, the findings of this study suggest soil texture and plant cover play an important role in controlling infiltration rates in reclaimed surface coal mines.

The number of Enterobacteriaceae, with particular attention given to the presence of Escherichia coli and Klebsiella pneumoniae, was determined in hospital effluents and municipal wastewater after various stages of purification. The emission of these microorganisms to the ambient air near wastewater treatment plant (WWTP) facilities and to the river water, which is a receiver of the WWTP effluent, was also studied using fluorescence in situ hybridization (FISH) and cultivation methods. The number of Enterobacteriaceae determined by cultivation and fluorescence methods in different kinds of sewage sample ranged from 0.5 × 10³ to 2.9 × 10⁶ CFU/ml and from 2.2 × 10⁵ to 1.3 × 10⁸ cells/ml, respectively. Their removal rates during treatment processes were close to 99 %, but the number of these bacteria in the WWTP outflow was quite high and ranged from 5.9 × 10³ to 3.5 × 10⁴ CFU/ml and from 1.1 × 10⁵ to 6.1 × 10⁵ cells/ml, respectively. In the river water and the air samples, the number of Enterobacteriaceae was also high and ranged from 4.1 × 10³ to 7.9 × 10³ CFU/ml and from 3 to 458 CFU/m³, respectively. The numbers of these microorganisms obtained from fluorescence and cultivation methods were statistically and significantly correlated; however, the analysis of the studied samples indicated that the FISH method gave values up to 10³-fold times greater than those obtained by the cultivation method. From a sanitary point of view, this means that the number of viable fecal bacteria is systematically underestimated by traditional culture-based methods. Thus, the FISH proves to be a method that could be used to estimate bacterial load, particularly in air samples and less contaminated river water.

Black rice husk ash (BRHA) was obtained by means of thermal degradation of raw rice husks (RRH) on a pilot plant fluidized bed reactor. BRHA was characterized using chemical analyses, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermal analysis. The kinetics was studied using batch adsorption technique and on the basis of prior characterization by X-ray diffraction patterns and scanning electron microscopy. The adsorption capacities of diesel fuel at 288, 293 and 298 K onto BRHA were determined. Results showed that the material studied has very high adsorption capacity and low cost and may successfully be used as an effective adsorbent to clean up spills of oil products in water basins. The adsorption of diesel fuel onto BRHA proceeds rapidly to reach adsorption equilibrium in about 10 min. The saturated BRHA can be burnt in incinerators, industrial ovens or steam generators, and through this way ecological and economic benefits are attained.

We evaluated the imbalance of the oxidative status in zebra mussel (Dreissena polymorpha) specimens exposed for 96 h to environmentally relevant concentrations (0.1, 0.5, and 1 μg/L) of the 2,2′,4,4′,5,6′-hexa BDE (BDE-154). The activities of three antioxidant enzymes, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and the phase II detoxifying enzyme glutathione S-transferase (GST), were measured in the cytosolic fraction from a pool of zebra mussels. Significant variations in the activity of each single enzyme were noticed at each treatment, indicating that exposure to BDE-154 was able to impair the oxidative status of treated bivalves through the increase of reactive oxygen species. In detail, SOD and GPx were significantly induced, while CAT and GST were depressed with respect to the baseline levels. These data have confirmed that the raise of oxidative stress is the main cause of the BDE-154-induced genetic damage observed in a previous study on the zebra mussel.