Pyrene, a four-ring polycyclic aromatic hydrocarbon that is highly resistant to degradation, persists in the environment and exerts its harmful effects toward humans, flora, and fauna when accumulated to a certain level. The ineffectiveness of conventional physical–chemical treatment methods has urged the emergence of biological treatments to degrade pyrene that persists in the environment. In this study, Pleurotus eryngii F032 was originally isolated from our laboratory due to its ability to degrade pyrene. Optimum conditions for pyrene degradation were determined using five different parameters, including pyrene concentration, incubation temperature, pH, agitation, and rhamnolipid concentration. The culture was incubated for 7, 15, 23, and 30 days, respectively, followed by pyrene extraction for degradation analysis. Results show that lower pyrene concentration requires less time for degradation by P. eryngi F032. Moreover, more time is needed for degradation when higher concentration is used, resulting in slower degradation. Optimum pyrene degradation conditions by P. eryngii F032 have been recorded at 40 °C incubation temperature, pH 3, and 2.5 % of rhamnolipid concentration with an agitation speed of 120 rpm. The capability of P. eryngii F032 to utilize pyrene as carbon and energy source depends on the presence of ligninolytic enzymes. The formation of protocatechuic acid resulting from pyrene degradation was detected via GC-MS analysis, which was further confirmed through spectrophotometric analysis.

The main objective of this study was to evaluate residuals from 28 pharmaceuticals and three phthalate esters (PAEs) in drinking waters, which were stored and further purified in different manners. Samples of drinking water from two different supply networks in Taiwan were collected in two batches from two research institutes (i.e., sampling sites N and S) in this study. Each batch of sampling was conducted on one Friday afternoon and the next Monday morning. Water storage tanks used in these two sampling sites are composed of different materials. Sampling points at each sampling site included one tap water pipeline, five water storage tanks, and five drinking fountains. It was found that retention of drinking water in the storage tanks over the weekend would be beneficial to spontaneous degradation of pharmaceuticals and PAEs. The preliminary results also showed that city water might have dissolved DiNP from modular water tanks made of fiberglass-reinforced plastics, whereas no such evidence was observed for water tanks made of stainless steel. Furthermore, a trace amount of pharmaceuticals and PAEs still could be detected in city waters, even in drinking fountain water.

Magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites were prepared by the facile citrate-gel thermal decomposition process. Their microstructure and magnetic properties were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and vibrating sample magnetometer (VSM). The as-prepared magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites were characterized with about 8-nm grains, specific surface area of 119.3 m²/g, and magnetization of 38.7 Am²/kg. The adsorption kinetics and adsorption isotherms of methyl blue (MB) and As(V) onto the magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites at room temperature were investigated. Adsorption kinetics of MB and As(V) onto the magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites have been researched using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, the statistic results show that the pseudo-second-order kinetic model is fitted well to describe the MB and As(V) adsorption process. The adsorption equilibrium data of MB and As(V) onto the magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites at room temperature were analyzed with Langmuir, Freundlich, and Temkin models, and the adsorption isotherms was more effectively described by the Freundlich model based on the values of the correlation coefficient. Figure The magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites were prepared by the citrate-gel thermal decomposition process. They show high adsorption capacities for methyl blue (MB) and arsenic(V) in aqueous solution, and the adsorption kinetics and isothermals were analyzed.

Corn cob silica (CCS), produced via a modification of the sol-gel method, can reduce heavy metal availability and stabilize contaminated soil on abandoned mining sites. Adding 5 % (w/w) CCS to mining site soil increased pH from 4.0 to 7.7, and cation exchange capacity increased from 94.5 to 100.3 cmol+/kg. Sequential extraction showed that adding CCS decreased heavy metal availability in the soil. Mobility factor (MF) values indicated that CCS reduced Pb mobility more than that of Zn or Cu in all fractions. Pb concentrations in leachate from all fractions using the toxicity characteristic leaching procedure (TCLP) were greatly decreased by adding 3 % (w/w) CCS. CCS similarly reduced Zn concentrations in TCLP leachate. CCS addition did not impact Cu concentrations in leachate, likely because concentrations were much lower than those of the other metals. As was generally less mobile than the heavy metals; however, As mobility and leachability tended to increase with CCS addition because its oxyanions arsenite and arsenate have low affinity for negatively charged surfaces on the CCS. Shoot and root growth of Spinacia oleracea L. (spinach) was much greater in CCS-treated soil than in unamended soil. Results demonstrate the utility of CCS to stabilize heavy metals in contaminated mining site soil, but this treatment may not be ideal for As-contaminated soils.

Studying the toxic risk of pesticide exposure to ladybird beetles is important from an agronomical and ecological perspective since larval and adult ladybirds are dominant predators of herbivorous pest insects (e.g., aphids) in various crops in China. This article mainly deals with the long-term effects of a single application of the insect growth regulator hexaflumuron on Coccinella septempunctata. A 72- h and a 33-day toxicity test with hexaflumuron (single application) were performed, starting with the second instar larvae of C. septempunctata. Exposure doses in the long-term experiment were based on the estimated 72-h acute LR50 (application rate causing 50 % mortality) value of 304 g active ingredient (a.i.) ha-1 for second instar larvae of C. septempunctata. The long-term test used five hexaflumuron doses as treatment levels (1/50, 1/100, 1/200, 1/400, and 1/800 of the 72-h acute LR50), as well as a solvent control and blank control treatment. The measurement endpoints used to calculate no observed effect application rates (NOERs) included development time, hatching, pupation, adult emergence, survival, and number of eggs produced. Analyzing the experimental data with one-way analysis of variance showed that the single hexaflumuron application had significant effects on C. septempunctata endpoints in the 33-day test, including effects on development duration (NOER 1.52 g a.i. ha-1), hatching (NOER 3.04 g a.i. ha-1), pupation (NOER 3.04 g a.i. ha-1), and survival (NOER 1.52 g a.i. ha-1). These NOERs are lower than the reported maximum field application rate of hexaflumuron (135 g a.i. ha-1) in cotton cultivation, suggesting potential risks to beneficial arthropods.

In this study, dissolved air flotation (DAF) was examined as a possible treatment method for the removal of chromium from aqueous solution and plating wastewater. Two coagulants, ferric chloride and poly aluminum chloride (PAC), were used for pretreatment of wastewater. Maximum removal of chromium was achieved for poly aluminum chloride (98 %). Artificial neural network was used for the prediction of the DAF system. The best neuron used for the prediction of chromium removal percentage of interpolated wastewater was 6 %. The mean score error and the coefficient correlation were 0.0007542 and 0.997, respectively.

The present study reports the remediation of radiocesium-137 (¹³⁷Cs) using napiergrass in Cs-contaminated soils of Fukushima Prefecture. Two field experiments were performed to examine the remediation effects in two different land-use soils (lowland and upland soils) using two different cutting frequencies (cut once or twice a year). Plant growth in the upland soil was significantly greater than that in the lowland soil. The¹³⁷Cs concentration (Bq kg⁻¹dry weight basis) in the aboveground parts and total Cs-removal ratio (CR) in the upland soil were also significantly higher than those in the lowland soil. In the lowland soil, cutting twice a year [at 12 and 24 weeks after transplanting (WAT)] was more effective for CR (P < 0.01) than cutting once a year (18 WAT); however, there was no significant difference of CR related to cutting difference in the upland soil as a result of the shading effect on the plants at second cutting. In the present study, aboveground dry matter weight was highly correlated with CR in both fields. Given the possibility to increase plant number per unit of land to increase aboveground biomass per unit of land, the potential Cs remediation effect could be much greater in a wide range of Cs-contaminated soils than the potential of napiergrass for Cs uptake demonstrated in the present study.

An on-line preconcentration system using solid-phase extraction with polytetrafluoroethylene was used for the determination of mercury by cold vapor atomic absorption spectrometry. The system uses electronically controlled valves and operates in two simple steps using sorption and elution. The Hg(II) ammonium pyrrolidinedithiocarbamate complexes are retained in a minicolumn packed with the sorbent. The elution, transportation, and reduction of the analyte ions are promoted by a solution of sodium tetrahydroborate(III). After optimization, the developed method showed the following analytical characteristics: a limit of detection of 0.02 μg L⁻¹, linearity of 0.07 to 2.00 μg L⁻¹, enrichment factor of 35, and sampling frequency of 27 h⁻¹. The accuracy of the method was tested by analyzing the certified reference material BCR-060 Lagarosiphon major (aquatic plant). The proposed method was applied to the determination of mercury in water samples.

Background. Although toxic waste sites have been well investigated in many developed countries, their prevalence and health impact have not been well documented in low and middle income countries where risks attributable to environmental pollution are generally higher than in developed nations. Methods. We compared the burden of disease from toxic waste sites expressed in disability-adjusted life-years (DALYs) with the same measurement for other threats in India, Indonesia and the Philippines. We used Blacksmith Institute for a Pure Earth’s DALY estimates for chemical exposure at 373 toxic waste sites in the 3 countries and World Health Organization (WHO) DALY estimates for different health conditions in the same countries. Results. Chromium VI causes the majority of DALYs among chemicals in India, while lead does so in the Philippines and Indonesia. In India, exposure to chromium VI showed higher DALY estimates than health conditions such as multiple sclerosis, Parkinson’s disease and various cancers. In Indonesia, exposure to chromium VI and lead presented higher DALYs than conditions such as upper respiratory infections. In the Philippines, lead had higher DALYs than most of the examined conditions, including malaria and human immunodeficiency virus (HIV)/AIDS. Conclusions. This study highlights that the burden of disease expressed in DALYs from toxic waste sites may be greater than previously recognized and greater than other well addressed public health threats. We call attention to the need for surveillance of toxic waste sites, epidemiological analysis of the associations between exposure to toxic chemicals and outcomes, and remediation of chemical contamination in India, Indonesia and the Philippines. Competing Interests. The authors declare no competing financial interests.

Background. Mercury is extensively used in artisanal small-scale gold mining in many parts of the world, including Zimbabwe. Mercury-free mining technologies are urgently needed to protect the biophysical environment and human health. Objective. The testing of local conditions for the introduction of a mercury-free gold mining technology entailing the use of borax in a field project in Kadoma/Zimbabwe. Materials and Methods. A one-day theoretical workshop and a two-day practical demonstration were conducted in Kadoma/Zimbabwe in December 2013. The willingness of the miners to change to another gold extraction technology other than mercury amalgamation, the local availability of appropriate materials and equipment, and the suitability of the ore for applying the borax technology for gold smelting were used as variables to test local conditions for introducing the borax method. Simple methods like trial and error and the collection of indices during discussions and observations were applied. Results. 1.11 grams of gold from half a ton of ore was the result of the demonstration. A number of potential improvements to the process were identified. A total of 50 invited local stakeholders took part in the theoretical workshop, and 30 to 40 decided immediately to also participate in field demonstrations. The project team noticed that the local miners were interested and impressed by catching very fine gold particles with the borax method. Conclusions. The project confirmed that the local conditions in Kadoma are appropriate for mining mercury-free gold. The optimization and comprehensive introduction of the borax method in the Kadoma gold mining region is recommended to eliminate the use of mercury. Competing Interests. The authors declare no competing financial interests.