Continuous application of organic and inorganic fertilizers can affect soil and food quality with respect to heavy metal concentrations. The risk of cadmium (Cd) contamination in a long-term (over 20 years) experimental field in North China with an annual crop rotation of winter wheat and summer maize was investigated. The long-term experiment had a complete randomized block design with seven fertilizer treatments and four replications. The seven fertilizer treatments were (1) organic compost (OM), (2) half organic compost plus half chemical fertilizer (OM + NPK), (3) NPK fertilizer (NPK), (4–6) chemical fertilizers without one of the major nutrients (NP, PK, and NK), and (7) an unamended control (CK). Soil samples from 0 to 20 cm were collected in 1989, 1999, and 2009 to characterize Cd and other soil properties. During the past 20 years, various extents of Cd accumulation were observed in the soil, and the accumulation was mainly affected by atmospheric dry and wet deposition and fertilization. In 2009, the average Cd concentration in the soil was 148 ± 15 μg kg⁻¹and decreased in the order of NPK ≈ OM + NKP ≈ PK > NP ≈ NK > OM ≈ CK. Sequential extraction of Cd showed that the acid-soluble fraction (F1, 32 ± 7 %) and the residual fraction (F4, 31 ± 5 %) were the dominant fractions of Cd in the soil, followed by the reducible fraction (F2, 22 ± 5 %) and oxidizable fraction (F3, 15 ± 6 %). The acid-soluble Cd fraction in the soil and Cd accumulation in the crops increased with soil plant available K. Fraction F3 was increased by soil organic C (SOC) and crop yields, but SOC reduced the uptake of soil Cd by crops. The long-term P fertilization resulted in more Cd buildup in the soil than other treatments, but the uptake of Cd by crops was inhibited by the precipitation of Cd with phosphate in the soil. Although soil Cd was slightly increased over the 20 years of intensive crop production, both soil and grain/kernel Cd concentrations were still below the national standards for environmental and food safety.

The influence of two neonicotinoids, i.e., imidacloprid (IMI) and acetamiprid (ACE), on soil microbial activities was investigated in a short period of time using a combination of the microcalorimetric approach and enzyme tests. Thermodynamic parameters such as QT(J g⁻¹soil), ∆Hₘₑₜ(kJ mol⁻¹), JQ/S(J g⁻¹ h⁻¹), k (h⁻¹), and soil enzymatic activities, dehydrogenase, phosphomonoesterase, arginine deaminase, and urease, were used to evaluate whole metabolic activity changes and acute toxicity following IMI and ACE treatment. Various profiles of thermogenic curves reflect different soil microbial activities. The microbial growth rate constant k, total heat evolution QT(expect for IMI), and inhibitory ratio I show linear relationship with the doses of IMI and ACE. QTfor IMI increases at 0.0–20 μg g⁻¹and then decreases at 20–80 μg g⁻¹, possibly attributing to the presence of tolerant microorganisms. The 50 % inhibitory ratios (IC₅₀) of IMI and ACE are 95.7 and 77.2 μg g⁻¹, respectively. ACE displays slightly higher toxicity than IMI. Plots of k and QTagainst microbial biomass-C indicate that the k and QTare growth yield-dependent. IMI and ACE show 29.6; 40.4 and 23.0; and 23.3, 21.7, and 30.5 % inhibition of dehydrogenase, phosphomonoesterase, and urease activity, respectively. By contrast, the arginine deaminase activity is enhanced by 15.2 and 13.2 % with IMI and ACE, respectively. The parametric indices selected give a quantitative dose-response relationship of both insecticides and indicate that ACE is more toxic than IMI due to their difference in molecular structures.

Harmful algal blooms (HABs) are a global problem, which can cause economic loss to aquaculture industry's and pose a potential threat to human health. More attention must be made on the development of effective detection methods for the causative microalgae. The traditional microscopic examination has many disadvantages, such as low efficiency, inaccuracy, and requires specialized skill in identification and especially is incompetent for parallel analysis of several morphologically similar microalgae to species level at one time. This study aimed at exploring the feasibility of using membrane-based DNA array for parallel detection of several microalgae by selecting five microaglae, including Heterosigma akashiwo, Chaetoceros debilis, Skeletonema costatum, Prorocentrum donghaiense, and Nitzschia closterium as test species. Five species-specific (taxonomic) probes were designed from variable regions of the large subunit ribosomal DNA (LSU rDNA) by visualizing the alignment of LSU rDNA of related species. The specificity of the probes was confirmed by dot blot hybridization. The membrane-based DNA array was prepared by spotting the tailed taxonomic probes onto positively charged nylon membrane. Digoxigenin (Dig) labeling of target molecules was performed by multiple PCR/RT-PCR using RNA/DNA mixture of five microalgae as template. The Dig-labeled amplification products were hybridized with the membrane-based DNA array to produce visible hybridization signal indicating the presence of target algae. Detection sensitivity comparison showed that RT-PCR labeling (RPL) coupled with hybridization was tenfold more sensitive than DNA-PCR-labeling-coupled with hybridization. Finally, the effectiveness of RPL coupled with membrane-based DNA array was validated by testing with simulated and natural water samples, respectively. All of these results indicated that RPL coupled with membrane-based DNA array is specific, simple, and sensitive for parallel detection of microalgae which shows promise for monitoring natural samples in the future.

Seasonal removal efficiency of 16 pharmaceuticals and personal care products was monitored in a wastewater treatment plant in České Budějovice, Czech Republic, over a period of 1 year (total amount of samples, n = 272). The studied compounds included four UV filters, three analgesics/anti-inflammatory drugs and nine anti-hypertensive/cardiovascular drugs. In most cases, elimination of the substances was incomplete, and overall removal rates varied strongly from −38 to 100 %. Therefore, it was difficult to establish a general trend for each therapeutic group. Based on the removal efficiencies (REs) over the year, three groups of target compounds were observed. A few compounds (benzophenon-1, valsartan, isradipine and furosemide) were not fully removed, but their REs were greater than 50 %. The second group of analytes, consisting of 2-phenylbenzimidazole-5-sulfonic acid, tramadol, sotalol, metoprolol, atenolol and diclofenac, showed a very low RE (lower than 50 %). The third group of compounds showed extremely variable RE (benzophenon-3 and benzophenon-4, codeine, verapamil, diltiazem and bisoprolol). There were significant seasonal trends in the observed REs, with reduced efficiencies in colder months.

Particulate matter is an important air pollutant, especially in closed environments like underground subway stations. In this study, a total of 13 elements were determined from PM₁₀and PM₂.₅samples collected at two subway stations (Imam Khomeini and Sadeghiye) in Tehran’s subway system. Sampling was conducted in April to August 2011 to measure PM concentrations in platform and adjacent outdoor air of the stations. In the Imam Khomeini station, the average concentrations of PM₁₀and PM₂.₅were 94.4 ± 26.3 and 52.3 ± 16.5 μg m⁻³in the platform and 81.8 ± 22.2 and 35 ± 17.6 μg m⁻³in the outdoor air, respectively. In the Sadeghiye station, mean concentrations of PM₁₀and PM₂.₅were 87.6 ± 23 and 41.3 ± 20.4 μg m⁻³in the platform and 73.9 ± 17.3 and 30 ± 15 μg m⁻³, in the outdoor air, respectively. The relative contribution of elemental components in each particle fraction were accounted for 43 % (PM₁₀) and 47.7 % (PM₂.₅) in platform of Imam Khomeini station and 15.9 % (PM₁₀) and 18.5 % (PM₂.₅) in the outdoor air of this station. Also, at the Sadeghiye station, each fraction accounted for 31.6 % (PM₁₀) and 39.8 % (PM₂.₅) in platform and was 11.7 % (PM₁₀) and 14.3 % (PM₂.₅) in the outdoor. At the Imam Khomeini station, Fe was the predominant element to represent 32.4 and 36 % of the total mass of PM₁₀and PM₂.₅in the platform and 11.5 and 13.3 % in the outdoor, respectively. At the Sadeghiye station, this element represented 22.7 and 29.8 % of total mass of PM₁₀and PM₂.₅in the platform and 8.7 and 10.5 % in the outdoor air, respectively. Other major crustal elements were 5.8 % (PM₁₀) and 5.3 % (PM₂.₅) in the Imam Khomeini station platform and 2.3 and 2.4 % in the outdoor air, respectively. The proportion of other minor elements was significantly lower, actually less than 7 % in total samples, and V was the minor concentration in total mass of PM₁₀and PM₂.₅in both platform stations.

This research investigated the 1,4-dioxane (1,4-D) degradation efficiency and rate during persulfate oxidation at different temperatures, with and without Fe²⁺addition, also considering the effect of pH and persulfate concentration on the oxidation of 1,4-D. Degradation pathways for 1,4-D have also been proposed based on the decomposition intermediates and by-products. The results indicate that 1,4-D was completely degraded with heat-activated persulfate oxidation within 3–80 h. The kinetics of the 1,4-D degradation process fitted well to a pseudo-first-order reaction model. Temperature was identified as the most important factor influencing the 1,4-D degradation rate during the oxidation process. As the temperature increased from 40 to 60 °C, the degradation rate improved significantly. At 40 °C, the addition of Fe²⁺also increased the 1,4-D degradation rate. Interestingly, at 50 and 60 °C, the 1,4-D degradation rate decreased slightly with the addition of Fe²⁺. This reduced degradation rate may be attributed to the rapid conversion of Fe²⁺to Fe³⁺and the production of an Fe(OH)₃precipitate which limited the ultimate oxidizing capability of persulfate with Fe²⁺under higher temperatures. Higher persulfate concentrations led to higher 1,4-D degradation rates, but pH adjustment had no significant effect on the 1,4-D degradation rate. The identification of intermediates and by-products in the aqueous and gas phases showed that acetaldehyde, acetic acid, glycolaldehyde, glycolic acid, carbon dioxide, and hydrogen ion were generated during the persulfate oxidation process. A carbon balance analysis showed that 96 and 93 % of the carbon from the 1,4-D degradation were recovered as by-products with and without Fe²⁺addition, respectively. Overall, persulfate oxidation of 1,4-D is promising as an economical and highly efficient technology for treatment of 1,4-D-contaminated water.

Sewage sludge (SS) with corn stalk (CS) was used to prepare SS-based activated carbon (SAC) by pyrolysis with ZnCl₂. The effects of mixing ratio on surface area and pore size distribution, elemental composition, surface chemistry, and morphology were investigated. The results demonstrated that the addition of CS into SS samples improved the surface area (from 92 to 902 m²/g) and the microporosity (from 1.2 to 4.1 %) of the adsorbents and, therefore, enhancing the adsorption performance. The removal of leachate chemical oxygen demand (COD) was also determined. It was found that the COD removal rate reached 85 % at pH 4 with the SAC (90 wt% CS) dosage of 2 % (g/mL) and an adsorption time of 40 min. The adsorption experimental data were fitted by both Langmuir and Freundlich adsorption isotherms. Long-chain alkanes and refractory organics were found in raw leachate, but could be removed by SAC largely.

Indoor plants can remove volatile organic compounds (VOCs) from the air. The majority of knowledge comes from laboratory studies where results cannot directly be transferred to real-life settings. The aim of this study was to develop an experimental test system to assess VOC removal by indoor plants which allows for an improved real-life simulation. Parameters such as relative humidity, air exchange rate and VOC concentration are controlled and can be varied to simulate different real-life settings. For example, toluene diffusion through a needle gave concentrations in the range of 0.10–2.35 μg/L with deviations from theoretical values of 3.2–10.5 %. Overall, the system proved to be functional for the assessment of VOC removal by indoor plants with Hedera helix reaching a toluene removal rate of up to 66.5 μg/m²/h. The mode of toluene exposure (semi-dynamic or dynamic) had a significant influence on the removal rate obtained by H. helix.

Size distribution (fine and coarse fraction) and solubility distribution (extracted and residual fraction) of 20 elements (As, Ba, Be, Cd, Co, Cu, Fe, Li, Mn, Pb, Ni, Rb, S, Sb, Se, Sn, Sr, Ti, Tl, V) in atmospheric particulate matter (PM) were determined during a 5-year field study carried out in the Po Valley (peri-urban area of Ferrara, in Northern Italy). By studying the contribution of the two size fractions and the two solubility fractions to the atmospheric concentration of each element, it was possible to obtain interesting information about the variability of PM sources, to assess the role played by atmospheric stability in determining pollution episodes, and to obtain an estimate of the bio-accessible fraction. Atmospheric stability is confirmed to be one of the main causes of atmospheric pollution in this area and is to be responsible for the pronounced winter increase in both PM and elemental concentration. Long-range transport of natural and polluted air masses caused temporary increases in PM and elemental concentration, while local industrial emission seemed to play a secondary role. Regulated elements were well below their concentration limit, but many toxic elements were in the form of fine particles and soluble chemical species, more accessible to the environment, and the human body.