In this study, we focused on the performance of phosphate recovery in the case of magnetic iron oxide (MIO) particles and iron oxide nanotubes (INTs) with synthetic wastewater. MIO particles were prepared by a co-precipitation method, and INTs were prepared with a potentiostatic anodization method of zerovalent iron foil in electrolyte-containing sulfate and fluoride. Although MIO had the fast adsorption rate, INT had a higher adsorption capacity per surface area rather than MIO. The adsorption isotherm of MIO and INT was approximated by a Freundlich type. Phosphate adsorbed on MIO and INT was effectively desorbed with alkaline solutions. For phosphate recovery, MIO needs a magnetic recovery device, whereas, when INT was used for phosphate recovery, another recovery step is not necessary. Both methods showed effective adsorption performance for phosphate recovery in wastewater.

To investigate the effect of different sizes, sex, and exposure time on Cu uptake capacity, mussels Mytilus galloprovincialis of different shell sizes were exposed to different Cu concentrations in different aquariums. In another experiment, mussels were exposed to stable dissolved Cu for 6 days in the laboratory. All mussels tissue concentrations were analyzed using energy dispersive X-ray fluorescence (EDXRF) spectrometry. At the end of uptake, the rate of increase of Cu level in the soft tissues of mussels in different aquariums was 3.84–7.92 times higher than before exposure. While the results of Cu concentrations were negatively correlated with the shell sizes in the control and second groups (r cₒₙₜᵣₒₗ = −0.862, r ₛₑcₒₙd = −0.851 p < 0.05), this relation was not observed in the other groups (p > 0.05). Also, results showed no significant difference between male and female (p > 0.05). On the other hand, Cu concentration values in soft tissue were monitored daily and observed to be increasing up to the third day but afterwards to be descending, thus indicating a significant effect of the exposure time-related Cu uptake by mussels. Therefore, the exposure time to Cu metal of the mussel should be taken into account in the marine pollution investigations. In addition, by using the obtained Cu heavy metal concentration results, the heavy metal intake by the human population was calculated by taking into account daily mussel consumption. The results were examined for potential human health risks and discussed. These results would be helpful to understand factors controlling Cu accumulation in mussels.

To analyze the daytime and phenological variations of canopy O₃ and CO₂ uptake of winter wheat, the canopy fluxes of wheat plants were measured using a chamber system with four different O₃ levels (0, 40, 80, and 120 nmol mol⁻¹) being applied. During the daytime (7:30–18:00 hours), canopy fluxes usually peaked around noon in early growing stages, while a generally decreasing trend from morning to afternoon was observed in the later stages. O₃ and CO₂ fluxes were positively and negatively correlated with O₃ concentration, respectively. Significant differences were observed in O₃ fluxes but CO₂ fluxes among O₃ treatments. Photosynthetically active radiation (PAR) and vapor pressure deficit (VPD) could affect canopy gas uptake in opposite ways. On the phenological timescale, both O₃ and CO₂ fluxes followed the variation of leaf area index (LAI) with the maximum occurring simultaneously at the booting stage. The daytime mean fluxes varied from −10.6 to −17.2 nmol m⁻² s⁻¹ for O₃ and from −5.9 to −19.6 μmol m⁻² s⁻¹ for CO₂. Quantitatively important O₃ deposition (−3.1∼−11.6 nmol m⁻² s⁻¹) was also observed at night with the ratios being about 40∼70 % relative to the daytime O₃ fluxes for most measuring days, which indicates a significant contribution from non-stomatal components to canopy O₃ removal. This study confirms that environmental variables and plant phenology are important factors in regulating canopy O₃ and CO₂ uptake. O₃ exposure (≤120 nmol mol⁻¹) could not significantly affect the CO₂ uptake of wheat canopy in a short time (ca. 10 min).

Reference materials are an indispensable element in the quality control of analytical results and procedures. Complicated natural matrices such as soil and sediment in the environment are subject to different processes. They are a source of various biochemical reactions, degradation, and biotransformation. Subject to these processes are all organic and inorganic pollutions which affect component parts of soil and sediment. The quantity and the composition of the organic and inorganic matter forming a given matrix, its origin, and the particle size fractions—all has an immediate influence on the content and the kind of pollution. The choice of the right reference material is a condition of the correct estimation of the reliability of the results. Many of the components forming the environmental matrix have influence on the content, stability, and homogeneity of the PCBs (e.g., the organic compound content and the percentage of minerals, particle size, moisture level). Reference material must be as similar as possible to real samples tested. Unfortunately, the majority of commercially available certified reference matrices for soils and bottom sediments containing polychlorinated biphenyls (PCBs) are not fully characterized as regards their makeup and the content of mineral and organic substances. Therefore, we face the question of matching (producing) appropriate CRMs for the tested matrices (samples of soils and sediments) to obtain dependable test results. Another solution to this problem could be creation of model compositions of soils and sediments with specific physical and chemical properties.

The objective of this research was to determine the process of atrazine transport compared to bromide and δO¹⁸ transport in sands near Denver. Three 1.5 × 2 × 1.5-m plots were installed and allowed to equilibrate for 2 years before research initiation and were instrumented with 1.5 × 2-m zero-tension pan lysimeters installed at 1.5-m depths. Additionally, each plot was instrumented with suction lysimeters, tensiometers, time domain reflectometry (TDR) moisture probes, and thermocouples (to measure soil temperature) at 15-cm depth increments. All plots were enclosed with a raised frame (of 8-cm height) to prevent surface runoff. During the 2-year period before research began, all suction and pan lysimeters were purged monthly and were sampled for fluids immediately prior to atrazine and KBr application to obtain background concentrations. Atrazine illustrated little movement until after a significant rainfall event, which peaked concentrations at depths of about 90 to 135 cm. Both Br⁻ and δO¹⁸ moved rapidly through the soil, probably owing to soil porosity and anion exclusion for Br⁻. Concentrations of atrazine exceeding 5.0 μL⁻¹ were observed with depth (90 to 150 cm) after several months. It appears that significant rainfall events were a key factor in the movement of atrazine in the sand, which allowed the chemicals to move to greater depths and thus avoid generally found biodegradation processes.

Previous pilot-scale studies have shown outstanding levels of efficiency in phosphorus removal by using hydrated oil shale ash (HOSA) sediments in horizontal subsurface flow (HSSF) filters with low greenhouse gas emissions. However, no long-term full-scale experiment has been conducted using this material. From September 2013 to December 2015, two HSSF filters with different hydraulic loading regimes (NH1 with a stable loading regime and NH2 with a fluctuating regime), used to treat municipal wastewater, were analysed to estimate greenhouse gas (GHG) fluxes and to develop a treatment system with minimised GHG emissions. The fluxes of CO₂, CH₄ and N₂O, as well as their emission factors were significantly lower when compared with studies where regular filter materials (sand, gravel, etc.) are in use. The fluctuating loading regime significantly increased CO₂ and N₂O fluxes (median values of −3.3 and 2.6 mg CO₂−C m⁻² h⁻¹, and 5.7 and 8.6 μg N₂O−N m⁻² h⁻¹ for NH1 and NH2 regimes, respectively), whereas no impact could be seen on CH₄ emissions (median 93.3 and 95.6 μg CH₄−C m⁻² h⁻¹, for NH1 and NH2, respectively). All GHG emissions were strongly affected by the chemical composition of the water entering into the system. The water purification efficiency of the system was satisfactory for most water quality parameters and excellent for phosphorus. Thus, the HOSA-filled filters have a good potential for municipal wastewater treatment with low GHG emission.

To provide growing population with sufficient food, greenhouse vegetable production has expanded rapidly in recent years in China and sustainability of its farming practices is a major concern. Therefore, this study assessed the sustainability of greenhouse vegetable farming practices from environmental, economic, and socio-institutional perspectives in China based on selected indicators. The empirical data were collected through a survey of 91 farm households from six typical greenhouse vegetable production bases and analysis of environmental material samples. The results showed that heavy fertilization in greenhouse vegetable bases of China resulted in an accumulation of N, P, Cd, Cu, Pb, and Zn in soil, nutrient eutrophication in irrigation water, and high Cd in some leaf vegetables cultivated in acidic soil. Economic factors including decreased crop yield in conventional farming bases, limited and site-dependent farmers’ income, and lack of complete implementation of subsidy policies contributed a lot to adoption of heavy fertilization by farmers. Also, socio-institutional factors such as lack of unified management of agricultural supplies in the bases operated in cooperative and small family business models and low agricultural extension service efficiency intensified the unreasonable fertilization. The selection of cultivated vegetables was mainly based on farmers’ own experience rather than site-dependent soil conditions. Thus, for sustainable development of greenhouse vegetable production systems in China, there are two key aspects. First, it is imperative to reduce environmental pollution and subsequent health risks through integrated nutrient management and the planting strategy of selected low metal accumulation vegetable species especially in acidic soil. Second, a conversion of cooperative and small family business models of greenhouse vegetable bases to enterprises should be extensively advocated in future for the unified agricultural supplies management and improved agricultural extension service efficiency, which in turn can stabilize vegetable yields and increase farmers’ benefits.

In this study, column leaching experiments were used to evaluate the leachability, distribution and bioavailability of phenanthrene and pyrene by root exudates from contaminated mangrove sediments. We observed that root exudates significantly promoted the release and enhanced the bioavailability of phenanthrene and pyrene from sediment columns. The concentration of phenanthrene and pyrene and cumulative content released from the analyzed sediment samples following root exudate rinsing decreased in the following order: citric acid > oxalic acid > malic acid. After elution, the total concentrations of phenanthrene and pyrene in sediment layers followed a descending order of bottom (9–12 cm) > middle (5–7 cm) > top (0–3 cm). Furthermore, a positive correlation between leachate pH values and PAH concentrations of the leachate was found. Consequently, the addition of root exudates can increase the leachability and bioavailability of phenanthrene and pyrene.

As increased greenhouse gas concentrations (GHG: N₂O, CO₂, CH₄) in our atmosphere remain a major concern, better quantifying GHG fluxes from natural systems is essential. In this study, we investigate GHG concentrations in saturated riparian sediments (dry, wet, mucky), streambed hyporheic zone sediments (pools, riffles), and stream water in a New York mountain stream for summer baseflow conditions, and attempt to identify the primary drivers (e.g., DO, DOC, NO₃⁻, and NH₄⁺, temp) of GHG concentrations at these locations. Although DO, DOC, NO₃⁻, and NH₄⁺ concentration patterns certainly explained some of the observed trends, the overall differences in GHG abundance in riparian water vs. hyporheic pool water vs. hyporheic riffle water strongly suggest that water velocity/mixing with the atmosphere is a key control on GHG concentration across locations. When all floodplain locations are considered, in-stream pools are hot spots of CO₂ and CH₄ concentrations relative to other in-stream locations. On the other hand, riparian areas are hot spots of CH₄ and CO₂ concentrations relative to stream locations. No clear patterns are observed for N₂O.

Plant stoichiometry has been used to diagnose phosphorus (P) limitation caused by increased atmospheric nitrogen (N) deposition. Spatial variability of N/P stoichiometry within a forested watershed has not yet been evaluated. This study conducted synoptic sampling of leaf matter in 27 plots within a temperate forested watershed on low P availability rock (serpentine bedrock) with a moderately high atmospheric N deposition (16 kg N ha⁻¹ year⁻¹) to assess the effects of spatial topographic variation on N/P stoichiometry. Leaf N and P concentrations and N/P ratios of Japanese cypress were assessed, and their spatial variations were evaluated across a catchment. Average leaf P concentration was low (0.66 ± 0.16 mg g⁻¹) across the sites, while leaf N concentration was high (13.0 ± 1.5 mg g⁻¹); subsequently, N/P ratios were high (21 ± 5). In addition, the aboveground biomass growth of Japanese cypress positively correlated with litter P, implying the P limitation of Japanese cypress at the study site. Leaf P concentrations responded to the index of convexity (IC) values more than those of N. Subsequently, the N/P ratio correlated with IC, suggesting that N/P ratios are susceptible to topographic features. This could be partly caused by smaller spatial variability of N availability compared with P, owing to increased atmospheric N deposition. Thus, topography should be taken into consideration when diagnosing P limitation caused by N deposition.