In this study, a novel water-insoluble zinc–Schiff base complex, Zn(II)-N-salicylaldehyde-2-hydroxyanil (abbreviated as Zn-salen), was synthesized and used as a heterogeneous photocatalyst for the activation of molecular oxygen to degrade organic pollutants in aqueous solution under visible light irradiation (λ ≥ 420 nm). The catalyst was characterized by FT-IR, UV–vis spectroscopy, NMR, and MS analysis. Zn-salen displays a selective adsorption and degradation of electropositive organics, such as rhodamine B (RhB), methylene blue (MB), and o-phenylenediamine (OPD). After using cetyl trimethyl ammonium bromide (CTAB) to change sulforhodamine B (SRB) into RhB-like electropositive molecule, the degradation of SRB increased up to 96 % after 4 h of irradiation, indicating that the selectivity arises from the charge interaction between the catalyst and substrates. Zeta potential of Zn-salen also reveals that the catalyst surface is negatively charged in neutral solution, suggesting that the catalyst is selective towards positively charged substrates due to an electrostatic force of attraction. The photocatalyst was active within a wide pH range (pH 3–11) and chemically stable and can be reused over 10 times. In addition, ¹O₂ and O₂·⁻ were involved in photocatalytic degradation but O₂·⁻ appears to be the primary reactive oxygen species.

This study investigates the effectiveness and mechanism of decreasing the bioavailability of Pb in bacterial culture and in pot experiments of Pb-contaminated paddy soil by Alishewanella sp. WH16-1. The WH16-1 strain was isolated from mine soil and exhibited high resistances to many heavy metals, especially to Pb²⁺ (2070 mg/L) and Cr (VI) (2340 mg/L). During cultivation of the WH16-1 strain with the addition of 100 mg/L Pb²⁺, Pb²⁺ was precipitated, and 84.13 % of Pb²⁺ was removed in 72 h. The precipitant was observed by transmission electron microscopy (TEM) and further confirmed to be PbS by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The WH16-1 strain was incubated in Pb²⁺-added paddy soil pot experiments for 60 days and compared with the uninoculated Pb²⁺-added paddy soil. Comparison showed that the exchangeable and carbonate-bound Pb in the paddy soil decreased by 14.04 and 10.69 % (P < 0.05), respectively. The Fe-Mn oxide-bound Pb, organic matter-bound Pb and the residual Pb increased by 4.47, 19.40, and 22.78 % (P < 0.05), respectively. Compared with the uninoculated Pb²⁺-added paddy soil, the dry weight of rice significantly increased by 28.59 %, and the Pb concentrations in rice, husk, leaves, and culms in Pb²⁺-added paddy soil pot experiment incubated with the WH16-1 strain significantly decreased by 26.18, 26.94, 26.61, and 25.56 % (P < 0.05), respectively. These results suggest that Alishewanella sp. WH16-1 can reduce the bioavailability of Pb in soil. This bacterium may be applicable for the biological stabilization of Pb in Pb-contaminated paddy soil.

The efficiency and mechanism of anion exchange resin Nanda Magnetic Polymer (NDMP) for removal of fluorescent dissolved organic matter in biologically treated textile effluents were studied. The bench-scale experiments showed that as well as activated carbon, anion exchange resin could efficiently remove both aniline-like and humic-like fluorescent components, which can be up to 40 % of dissolved organic matter. The humic-like fluorescent component HS-Em460-Ex3 was more hydrophilic than HS-Em430-Ex2 and contained fewer alkyl chains but more acid groups. As a result, HS-Em460-Ex3 was eliminated more preferentially by NDMP anion exchange. However, compared with adsorption resins, the polarity of fluorescent components had a relatively small effect on the performance of anion exchange resin. The long-term pilot-scale experiments showed that the NDMP anion exchange process could remove approximately 30 % of the chemical oxygen demand and about 90 % of color from the biologically treated textile effluents. Once the issue of waste brine from resin desorption is solved, the NDMP anion exchange process could be a promising alternative for the advanced treatment of textile effluents.

Given the 24-h turn-around time before swimming advisories are released, advisories issued to protect public health really only indicates ‘it may be unsafe to swim yesterday’. Predictive modelling for Escherichia coli concentrations at inflow-impacted beaches may be a favourable alternative to the current, routinely criticised monitoring approach. Using a total of 482 sets of meteorological and bacteriological data covering 14 swimming seasons, as well as environmental data of 10 inflow streams, this study developed models that could be used for predicting E. coli concentrations at five Lake Rotorua beaches. The models include predictor variables such as wind speed, antecedent rainfall, suspended solids at Puarenga, Utuhina and Ngongotaha stream inflows and particulate inorganic phosphorus concentration at Puarenga stream inflow. The combined 2011–2012 models had an average-adjusted R ² of 0.73, root mean square error (RMSE) of 0.33 logCFU/100 mL and captured 38 % of the variance in the validation data when used to predict E. coli concentrations for an additional 2 years (2013–2014). Among the individual beach models, predictive accuracy ranged from 88.89 to 92.31 % for the three beaches considered in the study. The developed models can provide a faster estimation of E. coli condition, potentially assisting local beach managers in the decision process related to swimming advisories issuance.

The potential of natural Chinese zeolite to remove ammonium from rainfall runoff following urea applications to a paddy rice field is assessed in this study. Laboratory batch kinetic and isotherm experiments were carried out first to investigate the ammonium adsorption capacity of the natural zeolite. Field experiments using zeolite adsorption barriers installed at drain outlets in a paddy rice field were also carried out during natural rainfall events to evaluate the barrier’s dynamic removal capacity of ammonium. The results demonstrate that the adsorption kinetics are accurately described by the Elovich model, with a coefficient of determination (R ²) ranging from 0.9705 to 0.9709, whereas the adsorption isotherm results indicate that the Langmuir–Freundlich model provides the best fit (R ² = 0.992) for the equilibrium data. The field experiments show that both the flow rate and the barrier volume are important controls on ammonium removal from rainfall runoff. A low flow rate leads to a higher ammonium removal efficiency at the beginning of the tests, while a high flow rate leads to a higher quantity of ammonium adsorbed over the entire runoff process.

Pathogenic human viruses cause over half of gastroenteritis cases associated with recreational water use worldwide. They are difficult to concentrate from environmental waters due to low numbers and small sizes. Rapid enumeration of viruses by quantitative polymerase chain reaction (qPCR) has the potential to improve water quality analysis and risk assessment. However, capturing and recovering these viruses from environmental water remain formidable barriers to routine use. Here, we compared the recovery efficiencies of human adenoviruses (HAdVs) and human polyomaviruses (HPyVs) from 10-L river water samples seeded with raw human wastewater (100 and 10 mL) using hollow-fiber ultrafiltration (HFUF) and glass wool filter (GWF) methods. The mean recovery efficiencies of HAdVs in river water samples through HFUF were 36 and 86 % for 100 and 10 mL of seeded human wastewater, respectively. In contrast, the estimated mean recovery efficiencies of HAdVs in river water samples through GWF were 1.3 and 3 % for 100 and 10 mL seeded raw human wastewater, respectively. Similar trends were also observed for HPyVs. Recovery efficiencies of HFUF method were significantly higher (P < 0.05) than GWF for both HAdVs and HPyVs. Our results clearly suggest that HFUF would be a preferred method for concentrating HAdVs and HPyVs from river water followed by subsequent detection and quantification with PCR/qPCR assays.

The present paper focuses on the determination of radiological characteristics of cultivated chernozem soil and crops from long-term field experiments, taking into account the importance of distribution and transfer of radionuclides in the soil-plant system, especially in agricultural cropland. The investigation was performed on the experimental fields where maize, winter wheat, and rapeseed were cultivated. Analysis of radioactivity included determination of the gross alpha and beta activity as a screening method, as well as the activities of the following radionuclides: natural (²¹⁰Pb, ²³⁵U, ²³⁸U, ²²⁶Ra, ²³²Th, ⁴⁰K, ⁷Be) and artificial (⁹⁰Sr and ¹³⁷Cs). The activities of natural and artificial (¹³⁷Cs) radionuclides were determined by gamma spectrometry, while the artificial radionuclide ⁹⁰Sr was determined by a radiochemical analytical method. Based on the obtained results for the specific activity of ⁴⁰K, ¹³⁷Cs, and ⁹⁰Sr, accumulation factors for these radionuclides were calculated in order to estimate transfer of radionuclides from soil to crops. The results of performed analyses showed that there is no increase of radioactivity that could endanger the food production through the grown crops.

Fourteen aquatic organism samples were collected from Bohai Bay, and concentrations of five heavy metals were measured to evaluate the pollution levels in aquatic organisms and the potential risk to human health. The concentrations of Zn and Cu were much higher than those of Cd, Cr, and Pb in all the organisms. In general, the heavy metal concentration levels were in the order phytoplankton < zooplankton < fish < shrimp < shellfish. Heavy metal concentrations in higher trophic-level aquatic organisms in Bohai Bay were compared to those in the organisms from other worldwide coastal waters. The concentration levels of most heavy metals were higher than the 75th percentile, except that Pb concentration was between the 25th and 50th percentiles. The calculated bioconcentration factors (BCF) of Cr, Cu, and Pb for phytoplankton were less than 100, indicating no accumulation in primary producers. The bioaccumulation factor (BAF) of Pb for zooplankton was the highest, indicating significant Pb accumulation in zooplankton. For higher trophic-level aquatic organisms, the order of BAF values was fish < shrimp < shellfish for most metals except for Pb. The human health risk assessment suggests that strict abatement measures of heavy metals must be taken to decrease the health risk caused by consuming aquatic products.

The main objective of the present study was to determine the optimum C/N ratio for converting waste paper and chicken manure to nutrient-rich manure with minimum toxicity. Six treatments of C/N ratio 20, 30, 40, 50, 60, and 70 (T1, T2, T3, T4, T5, and T6, respectively) achieved by mixing chicken manure with shredded paper were used. The study involved a composting stage for 20 days followed by vermicomposting with Eisenia fetida for 7 weeks. The results revealed that 20 days of composting considerably degraded the organic waste mixtures from all treatments and a further 7 weeks of vermiculture significantly improved the bioconversion and nutrient value of all treatments. The C/N ratio of 40 (T3) resulted in the best quality vermicompost compared to the other treatments. Earthworm biomass was highest at T3 and T4 possibly due to a greater reduction of toxic substances in these waste mixtures. The total N, total P, and total K concentrations increased with time while total carbon, C/N ratio, electrical conductivity (EC), and heavy metal content gradually decreased with time during the vermicomposting process. Scanning electron microscopy (SEM) revealed the intrastructural degradation of the chicken manure and shredded paper matrix which confirmed the extent of biodegradation of treatment mixtures as result of the composting and vermicomposting processes. Phytotoxicity evaluation of final vermicomposts using tomato (Lycopersicon esculentum), radish (Raphanus sativus), carrot (Daucus carota), and onion (Allium cepa) as test crops showed the non-phytotoxicity of the vermicomposts to be in the order T3 > T4 > T2 > T1 > T5 > T6. Generally, the results indicated that the combination of composting and vermicomposting processes is a good strategy for the management of chicken manure/paper waste mixtures and that the ideal C/N ratio of the waste mixture is 40 (T3).

Dust pollution can cause a significant damage of environment and endanger human health. Our study aimed to investigate epiphytic lichens and bryophytes in relation to long-term alkaline dust pollution and provide new insights into the bioindicators of dust pollution. We measured the bark pH of Scots pines and the species richness and cover of two cryptogam groups in 32 sample plots in the vicinity of limestone quarries (up to ca. 3 km) in northern Estonia. The bark pH decreased gradually with increasing distance from quarries. We recorded the changes in natural epiphytic communities, resulting in diversified artificial communities on pines near the pollution source; the distance over 2 km from the quarries was sufficient to re-establish the normal acidity of the bark and natural communities of both lichens and bryophytes. The cover of lichens and the number of bryophytes are a more promising indicator of environmental conditions than individual species occurrence. We confirmed previously proposed and suggested new bioindicator species of dust pollution (e.g., Lecidella elaeochroma, Opegrapha varia, Schistidium apocarpum). Limestone quarrying activity revealed a “parapositive” impact on cryptogamic communities, meaning that quarrying might, besides disturbances of natural communities, temporarily contribute to the distribution of locally rare species.