The reduction effects of riparian reforestation on runoff and nutrient export based on AnnAGNPS model in a small typical watershed, China

Abstract

The continuous deterioration of the aquatic environment in rivers and streams is increasingly causing social and political tensions. To alleviate aquatic environmental problems, especially for the nonpoint source pollution, establishment of riparian forest buffers has been demonstrated as an effective control measure. However, few comprehensive studies of the reduction effects of riparian reforestation on the aquatic environment have been performed, particularly in identifying the suitable widths of reforestation projects. In this paper, the Annualized Agricultural Non-Point Source (AnnAGNPS) model was used to simulate the reduction effects of riparian reforestation on runoff and nutrient loads in Wucun watershed, China. The results showed that 20-m, 40-m, and 60-m widths of riparian buffer reforestation had significant effects on the yearly loads of total nitrogen (TN) and total phosphorus (TP), with reduced rates of 23.21 to 56.2% and 18.16 to 52.14%, respectively. The reduction effect on annual runoff varied from 2.8 to 5.4%. Furthermore, the reduction effect of nutrients performed best during the transition period, while the best runoff reduction was found during the dry period. These distinct reductions indicated that the implementation of riparian forest buffers was capable of reducing the risk and frequency of flooding and eutrophication, especially during the wet and transition periods. Additionally, the 20-m width of riparian buffer reforestation achieved the highest reduction efficiency for runoff, and the 40-m width was the most suitable reforested riparian buffer width for TN and TP. Therefore, 40 m may be the optimum buffer width for the implementation of riparian reforestation in the Wucun watershed. These research results provided scientific information on selecting the optimum buffer width for aquatic environmental regulators and managers as the reduction effects of different widths of riparian buffers on runoff and nutrients were different when considering buffer reforestation.

http://bit.ly/2GXyaDq

Magnetic nanoferromanganese oxides modified biochar derived from pine sawdust for adsorption of tetracycline hydrochloride

Abstract

In this study, a new type of composite material, namely modified biochar (MBC), was synthesized by loading the magnetic ferromanganese oxide nanoparticles on pine biochar. BET, SEM, and FTIR were employed to analyze the surface properties and pore structures of MBC. In addition, XRD was adopted to examine the crystal structure of MBC. Characterization results showed that the surface area and porosity of MBC have been greatly improved, and the functional groups have been introduced by ferromanganese oxides. Adsorption experiments of tetracycline hydrochloride (TC) including kinetics, isotherms, thermodynamics as well as the influence of pH, salt ion strength, and the environmental risk of MBC, were evaluated. The results revealed that the experimental data conformed to the pseudo-second-order kinetic model and the Freundlich isotherm model. In the adsorption process, MBC showed excellent adsorption ability (maximum capacity for TC 100.74 mg g⁻¹) to BC (33.76 mg g⁻¹). In isotherm experiments, the maximum adsorption capacity of TC by MBC reached 177.71 mg g⁻¹. Toxicity studies showed that the MBC had no harm to the environment. To conclude, MBC has great potential for applications in removing TC from water.

http://bit.ly/2RzINAh

Spinal myoclonus following neuraxial anesthesia: a literature review

Abstract

Spinal myoclonus (SM) is a rare neurologic movement disorder following neuraxial anesthesia (NA). SM following NA (SM-NA) has insufficient clinical information and its pathogenesis remains to be elucidated. The aim of this review article was to summarize the past cases and consider SM-NA pathophysiology. Based on our PubMed search, it was revealed that SM-NA develops within several hours after neuraxial local anesthetic (LA) administration and resolves in a day without leaving neurologic compilations. It occurs primarily in the lower extremities, but can sometimes spread upward and affect the upper extremities and trunk. Although statistical adjustments are indispensable, analysis of the previous cases provided important facts that seem to be related with the mechanism of SM-NA. The frequently used LAs for spinal anesthesia were hyperbaric. SM-NA occurrence was more frequent in women. After initiation of spinal anesthesia, intrathecal hyperbaric LA distributes cephalad. In the LA elimination process, the large concentration differences in intrathecal LA may induce the partially functioning spinal neurons, resulting in myoclonus generation. The morphological features of the lumbar spine in women can predispose to a higher LA concentration difference. SM-NA is an unpredictable and rare neural complication following NA and should be confirmed by basic experiments and large-scale researches.

http://bit.ly/2QpLM9R

Ex situ catalytic biomass pyrolysis using mesoporous Ti-MCM-41

Abstract

Biomass has attracted considerable attention as energy, economic, and environmental asset, as result of its abundance and range of properties. The use of mesoporous catalysts during fast pyrolysis has been a highly important route to improve efficiency as well adding value to biomass. The addition of titanium to molecular sieves increases the efficiency of the pyrolysis reaction by improving production and selectivity of products of interest. This study aims at analyzing the catalytic pyrolysis products of elephant grass using titanium catalysts prepared at different Si/Ti molar ratios, i.e., 25 and 50. The material was supported on MCM-41 for the catalytic pyrolysis of biomass. The biomass pyrolysis reactions were performed in a micropyrolyzer coupled to a GC/MS analyzer. The Ti-MCM-41 samples were characterized by XRD, BET-specific area, and UV-visible. The distribution of pyrolysis products depended on process parameters such as temperature and catalyst type. The highest yield for hydrocarbon production, such as styrene, benzene, methylbenzene, and naphthalene, was observed at 600 °C using Si/Ti equal to 50.

http://bit.ly/2SEwJv0

Effect of grape seed extract on maternal toxicity and in utero development in mice treated with zearalenone

Abstract

The aims of this study were to determine the polyphone content of grape seed extract (GSE) and to assess their protective effects against zearalenone (ZEN)-induced maternal toxicity and in utero development defects in mice. Five groups of pregnant mice were treated orally during days 6–13 of gestation as follows: control group, corn oil as vehicle (0.1 ml/mice)-treated group, ZEN-treated group (25 mg/kg b.w), GSE-treated group (150 mg/kg b.w.), and ZEN plus GSE-treated group. All animals were sacrificed on the 19th day of gestation and samples of bone marrow were collected for the micronucleus assay. The maternal and developmental toxicity were carried out. The HPLC analyses revealed that GES is rich in gallic acid, syringic acid, vanillin, quercetin, and coumaric acid. ZEN administration resulted in severe maternal and developmental toxicity which included an increase of micronuclei formation in bone marrow, decreased maternal weight gain, and litter weight. It also induces fetal growth retardation, increased number of the aborted dams and resorbed fetuses, abnormality of fetal bone ossification, and number of fetuses with a hematoma. GSE showed positive effects on the pregnant mice and the developing fetuses. Moreover, it counteracted the detrimental effects of ZEN in dams and fetuses. It could be concluded that polyphenols in GSE are a promising candidate to protect against ZEN toxicity in highly endemic areas.

http://bit.ly/2Ayiocu

Gas thermal remediation of an organic contaminated site: field trial

Abstract

This paper investigated the performance of in situ gas thermal remediation (GTR) technique for the remediation of organic contaminated soil and groundwater. The pollutants of the site are mainly benzene, chlorobenzene, and petroleum. To evaluate the effectiveness of GTR, 100-m² site soil with a depth of up to 18 m were installed with heating wells and extraction wells. The temperature in the GTR system was 100~200 °C, and the pressure was 0.5~2.0 kPa. It ran for 34 days. Later, soil and groundwater were sampled 7 days after treatment. The results show that the temperatures of the central remediation area and the heating well surrounding area were higher than that of the edge position. The average temperature of the surface soil was the lowest. The highest temperatures were found at depths of − 3 m and − 6 m. In addition, the removal rates of benzene, chlorobenzene, and petroleum in soil were up to 99.81%, 99.72%, and 98.23%, respectively. Meanwhile, those for groundwater were up to 98.77%, 97.70%, and 99.99%, respectively. The removal rate of pollutants in soil is affected by temperature and the nature of the soil. Although many GTR projects have been applied in the USA, this project is the first engineering application project of GTR technology in China. The results present the good in situ organic removal efficiency of GTR system in this study and therefore provide a guidance and technical support for similar projects in China.

http://bit.ly/2SEVkj4

Ecotoxicological assessment of Fluazuron: effects on Folsomia candida and Eisenia andrei

Abstract

The cattle production in Brazil has increased considerably in the last years, mainly due to the control of parasite infestation of the animals, which cause loss of productivity to the sector. Fluazuron is an active ingredient (a.i.) of the benzoylurea class used to control ticks in cattle. As this a.i. has been found unchanged in animal feces, which may present a risk to edaphic organisms, this study aimed to assess the effects of fluazuron on survival, reproduction, and behavior of the soil invertebrates Folsomia candida and Eisenia andrei, through ecotoxicological assays. We carried out bioassays in a tropical artificial soil (TAS) spiked with increasing doses of the insecticide. Earthworm mortality was found only at the highest tested fluazuron concentration (LOEC = 160 mg a.i. kg⁻¹ dry soil and NOEC = 80 mg kg⁻¹), while the reproduction of F. candida and E. andrei was reduced at lower fluazuron concentrations (EC₅₀ = 4.48 mg kg⁻¹ and EC₅₀ = 20.8 mg kg⁻¹, respectively). Avoidance behavior was detected for both species at lower concentrations than those that caused impacts on reproduction, indicating that the substance may affect the soil habitat function. Since the possible adverse effects of fluazuron on edaphic fauna are still unknown or neglected, this study also warns about the possible harmful effect of veterinary pharmaceutical products on edaphic fauna.

http://bit.ly/2AzYVYP