Manure application on frozen soil, which is a common practice in the upper Midwest of USA, results in degraded soil and water quality. During snowmelt or precipitation events, water runoff carries nutrients into nearby streams and impairs the water quality. There is a need, therefore, to identify improved management of manure application in the soils. This study was conducted to assess water quality impacts associated following manure application during winter months when soil is completely covered with snow. The study site included three watersheds, named south (SW), east (CW), and north (NW) managed with a corn (Zea mays L.)-soybean (Glycine max L.) rotation located in South Dakota. The SW and NW were used as treatment, and CW as the control watershed. The treatments included manure application on the upper half of the SW and lower half of the NW, and CW received no manure application. This study showed that manure improved soil properties including infiltration rate and organic matter. Nitrogen and phosphorus losses in the surface runoff were higher from NW compared to that of SW. The CW had similar nutrient losses compared to the NW with slight differences. It can be concluded that maintaining a setback distance can help in improving the environmental quality as well as managing the agricultural wastes during the winter months.

Adsorption isotherms were constructed to evaluate the potential use of water lettuce (Pistia stratiotes) dry biomass for the biosorption of zinc and cadmium. One gram of dry biomass of this plant was treated with five increasing doses of zinc (1.8, 18, 50, 79, and 105 mg L⁻¹) and four doses of cadmium (0.01, 0.1, 1, and 10 mg L⁻¹), for nine collection times (1, 3, 6, 12, 24, 36, 48, 60, and 72 h). The levels of these metals were determined by atomic absorption spectrophotometry. To evaluate changes in the surface morphology of the dry biomass, scanning electron microscopy (SEM) images were taken of the samples subjected to the greatest contamination, and these were compared with the images of the samples without zinc and cadmium (control). The ISOFIT software was used to select the isotherm model that best fit the biosorption of metals by water lettuce dry biomass. The linear model was determined to be the best-fitting isotherm model, because it had the lowest corrected Akaike information criterion (AICc) value and a Akaike weight (AICw) value closest to one, which indicates the high affinity of the biosorbent for the adsorbates evaluated. The results for both metals demonstrated greater than 70% reductions in the concentrations of the metals in the contaminated solutions. The SEM images indicated changes in the morphology of the contaminated biomass, thus demonstrating the biosorption mechanisms and confirming the potential of the dry biomass of this plant for use in the remediation of solutions contaminated with zinc and cadmium.

Predicting impacts of oil spills on the environment requires a better understanding of the effects on aquatic organisms, both for single hydrocarbons and for their interactions. In this study, the individual and combined effects of the petroleum hydrocarbons phenanthrene and dibenzothiophene (DBT) were assessed on the reproductive behavior of the freshwater amphipod Hyalella azteca. Following a 24-h exposure to single polycyclic aromatic hydrocarbons (PAHs), or an equimolar mixture of phenanthrene–dibenzothiophene (Phen–DBT), mate-guarding behavior was assessed. This consisted of an assessment of the incidence of mate guarding right at the end of the exposure period and quantification of the “time taken to initiate mate guarding” (TIMG) and “proportion of time spent mate guarding” (PTMG) during a subsequent 10-min observation period in clean water. Both Phen and DBT reduced the incidence of mate guarding at the end of the exposure. TIMG and PTMG during the observation period were not affected by the PAHs other than indirectly by their effect on mate guarding status at the end of the exposure. The interaction between Phen and DBT varied among the mate guarding measures. For mate guarding status at the end of the exposure period and for TIMG, the interaction did not deviate statistically from an additive effect. For PTMG, the overall interaction was a synergistic one. This study’s findings point out that assessments of hydrocarbon toxicity need to take into account that subtle reproductive behaviors (that may be important for population persistence) may be negatively affected. The results also show that the general assumption of additive effects among PAHs may be an oversimplification.

Nitrogen recovery and valorization is gaining interest due to the current need for nitrogen removal, so it is of great interest that ammonium-selective sorbents be evaluated. In this study, a zeolitic material synthesized from coal fly ash (Ze–Na) in sodium form as well as its modification to potassium form (Ze–K) were evaluated as sorbent materials for the recovery of ammonium from wastewater effluents. The sorption performance was assessed through three consecutive sorption-desorption cycles reporting opposite behavior in terms of ammonium sorption capacity. Decreasing in the case of Ze–Na and to slightly increase for Ze–K due to alkaline activation of zeolite surface. The maximum sorption capacities obtained were 109 ± 4 mg NH₄/g and 33 ± 1 mg NH₄/g for Ze–Na and Ze–K, respectively. It is important to point out that in the case of Ze–Na, the maximum sorbent capacity was obtained during the first sorption cycle whereas in the case of Ze–K, it was obtained during the last working cycle due to the alkaline regeneration. Kinetic studies showed that after every regeneration step, the sorption kinetics turn faster as alkaline desorption increased the zeolite-specific surface, thus increasing the size of porous and enhancing the diffusion through the particle. Results obtained indicate that sorption capacity decreased significantly after every working cycle using Ze–Na whereas Ze–K followed the opposite behavior despite its initial lower sorption capacity.

Most bioremediation studies on volatile organic compounds (VOCs) have focused on a single contaminant or its derived compounds and degraders have been identified under single contaminant conditions. Bioremediation of multiple contaminants remains a challenging issue. To identify a bacterial consortium that degrades multiple VOCs (dichloromethane (DCM), benzene, and toluene), we applied DNA-stable isotope probing. For individual tests, we combined a ¹³C-labeled VOC with other two unlabeled VOCs, and prepared three unlabeled VOCs as a reference. Over 11 days, DNA was periodically extracted from the consortia, and the bacterial community was evaluated by next-generation sequencing of bacterial 16S rRNA gene amplicons. Density gradient fractions of the DNA extracts were amplified by universal bacterial primers for the 16S rRNA gene sequences, and the amplicons were analyzed by terminal restriction fragment length polymorphism (T-RFLP) using restriction enzymes: HhaI and MspI. The T-RFLP fragments were identified by 16S rRNA gene cloning and sequencing. Under all test conditions, the consortia were dominated by Rhodanobacter, Bradyrhizobium/Afipia, Rhizobium, and Hyphomicrobium. DNA derived from Hyphomicrobium and Propioniferax shifted toward heavier fractions under the condition added with ¹³C-DCM and ¹³C-benzene, respectively, compared with the reference, but no shifts were induced by ¹³C-toluene addition. This implies that Hyphomicrobium and Propioniferax were the main DCM and benzene degraders, respectively, under the coexisting condition. The known benzene degrader Pseudomonas sp. was present but not actively involved in the degradation.

Currently, the use of nanotechnologies is in rapid expansion, which entails increasing risks of environmental contamination by nanoparticles. Many studies describe the toxic effects on human cells, but little is known about the possible adverse effects on plants. Currently, various nanoparticles are often detected in streams, wastewater, and sewage due to widespread nanoparticle uses. We studied the accumulation and the effect of metal oxide nanoparticles together with their bulk counter particles and soluble metal salts on the growth of a wetland plant species true fox-sedge (Carex vulpina L.). The concentration 100 mg/l of copper nanoparticles significantly affected the growth of the plants, roots characteristics, and content of the photosynthetic pigments in leaves, while the same concentration of iron nanoparticles did not reduced any of the measured items. Using the bulk materials, the effect was very similar.

Oil spills might lead to severe environmental impacts to the affected fauna, disrupting local food webs, and causing mass mortality in many species. However, little is known about long-term impacts of oil spills, or even if such impacts can be detectable after several generations. In this study, we investigate the genetic variability of three freshwater species—Mimagoniates microlepis (Characiformes: Characidae), Scleromystax barbatus (Siluriformes: Callichthyidae), and Phalloceros harpagos (Cyprinodontiformes: Poeciliidae)—in rivers that were affected by a large oil spill in the state of Paraná, southern Brazil, on February of 2001. Samples were obtained from nine different locations, such that rivers that were directly affected by the oil spill could be compared with similar rivers in the same region that were unaffected. A fragment of the cytochrome C oxidase subunit I mitochondrial gene was sequenced from each specimen, and the level of genetic variability was assessed. Based on estimates of haplotype and nucleotide diversity, no impact of the oil spill could be detected in impacted rivers. These results suggest that fish populations in the region showed resilience to the pollutant, such that immigration from other locations was able to reestablish levels of genetic variability comparable to those of unimpacted rivers.

China’s rapid industrialization and urbanization has come at a staggering cost to the environment. In recent years, urban air pollution has been a serious environmental issue in Chinese cities that often hits news headlines in China and abroad. Based on the most recent data available, this paper employs two indices to examine the spatial and temporal patterns of some major air pollutants, including sulfur dioxide (SO₂), nitrogen dioxide (NO₂), zone (O₃), inhalable particulate matter (PM₁₀), and fine particulate matter (PM₂.₅), in China’s major cities and city regions. The results show that these pollutants display distinct spatial and seasonal variations. Overall, air pollution is much more serious in northern parts of the country, especially in large cities and a few major urban agglomerations, but we also find concentrations of air pollutants in urban agglomerations in southern China. Seasonally, Chinese cities suffer from air pollution especially PM₂.₅ pollution most in winter while summer is the cleanest season for most cities. Regional variations exist in composition of leading air pollutants and in influencing factors. Meteorological factors, such as wind speed, precipitation, temperature, air pressure, and relative humidity, often have important impacts on PM₂.₅ concentration, though their specific contributions vary across different cities. We argue that effective air pollution control policies should be regional in nature, but cross-border cooperation between regional and local governments is essential in order to tackle the problem of air pollution more effectively.

This study sought to analyze the effects of the herbicide quinclorac on body condition indices; plasma levels of corticosterone, glucose, and uric acid; activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST); and levels of lipid peroxidation (LPO) in the liver and caudal muscle of American bullfrog (Rana catesbeiana) tadpoles. After a 7-day acclimation period, animals were exposed to four concentrations (0.05, 0.1, 0.2, and 0.4 μg/L) of herbicide for a further 7 days. Then, blood samples were obtained, animals were euthanized, and the liver and caudal muscle resected. Levels of corticosterone and uric acid were reduced in tadpoles exposed to the highest concentration of herbicide, and this reduction was preceded by an increase in glucose levels. In the liver tissue, LPO was increased after exposure to 0.1 μg/L quinclorac, followed by a return to baseline values in the remaining concentrations; this response was accompanied by an increase in SOD and GST and reduction of tissue protein levels. At the highest concentration, a reduction in activity of all enzymes was observed, with protein returning to control-like levels. In muscle, SOD and GST levels declined with exposures up to 0.1 g/L and 0.4 μg/L, respectively, whereas LPO decreased in animals exposed to 0.1 μg/L. These results suggest participation of nonenzymatic antioxidant defenses, as demonstrated by the reduction in uric acid levels. Exposure to the range of quinclorac concentrations used in this study slowed body mass and length gain, reduced corticosterone levels, and modulated antioxidant defenses. Graphical abstract ᅟ

Water quality assessment typically includes the determination of chemical oxygen demand (COD) by oxidation of organic matter with Cr(VI) in an acidic medium followed by digestion. Unfortunately, the required reagents are harmful and the reaction times are rather long. We investigated earlier the use of H₂O₂ as a more environmentally friendly oxidizing agent to replace the hazardous chromates. In the present study, we have furthered this possibility by incorporating the use of H₂O₂ in the presence of UV light. A protocol has been devised and tested with standards and real samples that replaces toxic Cr(VI), halves the amount of silver sulfate required, and greatly reduces the necessary reaction time, thus yielding a faster and more environmentally sound method.