Effects of law enforcement and community outreach on mammal diversity in a biodiversity hotspot

Management activities such as law enforcement and community outreach are thought to affect conservation outcomes in protected areas, but their importance relative to intrinsic environmental characteristics of the parks and extrinsic human pressures surrounding the parks have not been explored. Furthermore, it is not clear which is more related to conservation outcomes—the management itself or local people's perceptions of the management. We measured objective (reports by park staff) and subjective (reports by local people) levels of community outreach and law enforcement based on responses to 374 questionnaires. We estimated mammal abundance and diversity of 6 protected areas based on data from 115 camera traps in Xishuangbanna, southwest China, a biodiversity hotspot with high hunting and land-conversion pressures. We then examined correlations among them and found that local people's perception of law enforcement was positively related to the local abundance of 2 large, hunted species, wild boar (Sus scrofa) (β = 15.22) and muntjac (Muntiacus vaginalis) (β = 14.82), but not related to the abundance of smaller mammals or to objective levels of enforcement. The subjective frequency of outreach by park staff to local communities (β = 3.42) and park size (β = 3.28) were significantly and positively related to mammal species richness, whereas elevation, human population density, and subjective frequency of law enforcement were not. We could not conclude that community outreach and law enforcement were directly causing increased mammal abundance and diversity. Nevertheless, the patterns we detected are some of the first empirical evidence consistent with the idea that biodiversity in protected areas may be more positively and strongly related to local perceptions of the intensity of park management than to either intrinsic (e.g., elevation, park size) or extrinsic (e.g., human population density) environmental factors.     

Comparison of CNT-PVA membrane and commercial polymeric membranes in treatment of emulsified oily wastewater

CNT-PVA membrane was fabricated and compared with polymeric membranes. The separation performance was evaluated by homemade and cutting fluid emulsions. The three membranes show similar oil retention rates. CNT-PVA membranes have higher permeation fluxes compared with polymeric membranes. CNT-PVA membrane shows higher fouling resistance. Membrane separation is an attractive technique for removal of emulsified oily wastewater. However, polymeric membranes which dominate the current market usually suffer from severe membrane fouling. Therefore, membranes with high fouling resistance are imperative to treat emulsified oily wastewater. In this study, carbon nanotube-polyvinyl alcohol (CNT-PVA) membrane was fabricated. And its separation performance for emulsified oily wastewater was compared with two commercial polymeric membranes (PVDF membrane and PES membrane) by filtration of two homemade emulsions and one cutting fluid emulsion. The results show that these membranes have similar oil retention efficiencies for the three emulsions. Whereas, the permeation flux of CNT-PVA membrane is 1.60 to 3.09 times of PVDF membrane and 1.41 to 11.4 times of PES membrane, respectively. Moreover, after five consecutive operation circles of filtration process and back flush, CNT-PVA membrane can recover 62.3% to 72.9% of its initial pure water flux. However, the pure water flux recovery rates are only 24.1% to 35.3% for PVDF membrane and 6.0% to 26.3% for PES membrane, respectively. Therefore, CNT-PVA membrane are more resistant to oil fouling compared with the two polymeric membranes, showing superior potential in treatment of emulsified oily wastewater.     

Reconsideration on the effect of nitrogen on mixed culture polyhydroxyalkanoate production toward high organic loading enrichment history

Effect of nitrogen on mixed culture PHA production was reconsidered. Enrichment history of PHA accumulating culture was discussed. Higher PHA content and biomass growth were achieved in presence of nitrogen. Enrichment strategy toward higher PHA accumulation was investigated. Microbial community succession in PHA accumulation phase was investigated. In most of the operating strategies for mixed microbial cultures polyhydroxyalkanoate (PHA) production, moderate organic loads and low nitrogen concentrations are used, however, the real waste streams contain variable concentrations of carbon and nitrogen. To evaluate the effect of enrichment history on PHA producer and production the various carbon and nitrogen levels were utilized during the accumulation phase. Different operating strategies were applied in three sequencing batch reactors (SBRs) subjected to aerobic dynamic feeding. The maximum PHA production of the enriched cultures under nutrient excess, limitation and starvation (Cmol/Nmol ratio of 8, 40 and ∞, respectively) was evaluated in batch assays. A higher PHA content and biomass growth were achieved in the nutrients presence in comparison to the nutrient starvation condition. The cultures from the SBR treated under short sludge retention time, high organic loading rate, short cycle length (SBR#3) and nutrient excess reached the maximum PHA content (54.9%) and biomass increase (38.9%). Under nutrient limitation, the negative biomass growth was observed under nutrient starvation because of the sampling loss. The succession of microbial communities in SBRs and batch assays was analyzed using terminal restriction fragment length polymorphism. The SBR#3 had the best overall PHA production performance considering its high PHA content and productivity in all nutrient content, it indicates that nitrogen has a substantial impact on PHA yield especially when high organic loading rate enrichment history is involved.     

Enhanced activation of peroxymonosulfate by CNT-TiO2 under UV-light assistance for efficient degradation of organic pollutants

CNT-TiO₂ composite is used to activate PMS under UV-light assistance. Superior performance is due to the enhanced electron-transfer ability of CNT. SO₄•⁻, •OH and ¹O₂ play key roles in the degradation of organic pollutants. In this work, a UV-light assisted peroxymonosulfate (PMS) activation system was constructed with the composite catalyst of multi-walled carbon nanotubes (CNT) - titanium dioxide (TiO₂). Under the UV light irradiation, the photoinduced electrons generated from TiO₂ could be continuously transferred to CNT for the activation of PMS to improve the catalytic performance of organic pollutant degradation. Meanwhile, the separation of photoinduced electron-hole pairs could enhance the photocatalysis efficiency. The electron spin resonance spectroscopy (EPR) and quenching experiments confirmed the generation of sulfate radical (SO₄•⁻), hydroxyl radical (•OH) and singlet oxygen (¹O₂) in the UV/PMS/20%CNT-TiO₂ system. Almost 100% phenol degradation was observed within 20 min UV-light irradiation. The kinetic reaction rate constant of the UV/PMS/20%CNT-TiO₂ system (0.18 min⁻¹) was 23.7 times higher than that of the PMS/Co₃O₄ system (0.0076 min⁻¹). This higher catalytic performance was ascribed to the introduction of photoinduced electrons, which could enhance the activation of PMS by the transfer of electrons in the UV/PMS/CNT-TiO₂ system.     

Research progress on distribution,sources, identification,toxicity, and biodegradation of microplastics in the ocean,freshwater, and soil environment

• Microplastics are widely found in both aquatic and terrestrial environments. • Cleaning products and discarded plastic waste are primary sources of microplastics. • Microplastics have apparent toxic effects on the growth of fish and soil plants. • Multiple strains of biodegradable microplastics have been isolated. Microplastics (MPs) are distributed in the oceans, freshwater, and soil environment and have become major pollutants. MPs are generally referred to as plastic particles less than 5 mm in diameter. They consist of primary microplastics synthesized in microscopic size manufactured production and secondary microplastics generated by physical and environmental degradation. Plastic particles are long-lived pollutants that are highly resistant to environmental degradation. In this review, the distribution and possible sources of MPs in aquatic and terrestrial environments are described. Moreover, the adverse effects of MPs on natural creatures due to ingestion have been discussed. We also have summarized identification methods based on MPs particle size and chemical bond. To control the pollution of MPs, the biodegradation of MPs under the action of different microbes has also been reviewed in this work. This review will contribute to a better understanding of MPs pollution in the environment, as well as their identification, toxicity, and biodegradation in the ocean, freshwater, and soil, and the assessment and control of microplastics exposure.     

Influence of extracellular polymeric substances from activated sludge on the aggregation kinetics of silver and silver sulfide nanoparticles

• The NPs aggregation in the electrolyte solution is consistent with the DLVO theory. • In NaNO₃ and low Ca(NO₃)₂, EPS alleviates the NPs aggregation by steric repulsion. • In high Ca(NO₃)₂, EPS accelerates the NPs aggregation by exopolysaccharide bridging. • Ag₂S NPs have stronger stability compared with Cit-Ag NPs in aqueous systems. Extracellular polymeric substances (EPS) in activated sludge from wastewater treatment plants (WWTPs) could affect interactions between nanoparticles and alter their migration behavior. The influence mechanisms of silver nanoparticles (Ag NPs) and silver sulfide nanoparticles (Ag₂S NPs) aggregated by active EPS sludge were studied in monovalent or divalent cation solutions. The aggregation behaviors of the NPs without EPS followed the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The counterions aggravated the aggregation of both NPs, and the divalent cation had a strong neutralizing effect due to the decrease in electrostatic repulsive force. Through extended DLVO (EDLVO) model analysis, in NaNO₃ and low-concentration Ca(NO₃)₂ (<10 mmol/L) solutions, EPS could alleviate the aggregation behaviors of Cit-Ag NPs and Ag₂S NPs due to the enhancement of steric repulsive forces. At high concentrations of Ca(NO₃)₂ (10‒100 mmol/L), exopolysaccharide macromolecules could promote the aggregation of Cit-Ag NPs and Ag₂S NPs by interparticle bridging. As the final transformation form of Ag NPs in water environments, Ag₂S NPs had better stability, possibly due to their small van der Waals forces and their strong steric repulsive forces. It is essential to elucidate the surface mechanisms between EPS and NPs to understand the different fates of metal-based and metal-sulfide NPs in WWTP systems.     

Changes of Soil Microbiological Properties Caused by Land Use Changing From Rice–Wheat Rotation to Vegetable Cultivation

A survey was done recently in Jiaxing city of Zhejiang Province in the Yangtze River Delta to compare the differences of soil microbiological properties among paddy soils with different land use including continuous open-field vegetable cultivation (OFVC), plastic-greenhouse vegetable cultivation (PGVC) and traditional rice–wheat rotation (RWR). The soil types included are percolating, permeable and waterlogged paddy soils. The results indicate that the microbial flora was markedly changed as the land use changed for all the three soil types. In continuous vegetable cultivation soils, especially in PGVC soils, the bacteria amounts decreased dramatically, but the fungal and actinomyce amounts increased as compared with RWR soils. The dehydrogenase activities decreased significantly in vegetable soils, especially in PGVC soils as compared with RWR soils. The microbial biomass C and the total phospholipid contents (TPL) in vegetable cultivation soil greatly decreased as compared with RWR soils. Biolog analysis indicated that the kinds of carbon sources that could be metabolized by native microbes in PGVC soils greatly decreased as compared with OFVC soils and RWR soils, revealing that microbial diversity had decreased since land use change. The activities of some soil enzymes including urease, invertase and phosphase were all lower in OFVC soils than those in RWR soils, and those in PGVC soils were the lowest. The degradation of microbiological activities in continuous vegetable cultivation soils, especially in PGVC soils, as compared with RWR soils might have been caused by soil acidification and accumulation of salts due to overuse of both organic and inorganic fertilizers in vegetable cultivation.     

The effect of limiting nutrient on metal toxicity to selenastrum capricornutum

Metal toxicity on selenastrum capricornutum were examined by batch culture and chemostat culture system. EC₅₀ values under nutrient‐limited condition and saturated condition were compared. The two EC_5Os differed by a factor of 10.6 for Cd in batch test, and differed by a factor of 6.5 in continuous test. Both batch and continuous test results indicate that inhibition on algal growth is more severe under nutrient‐limited conditions compared to that under near saturation conditions.

Strong correlation, as characterized by the correlation coefficient ρ, were found between the activation level (nutrient requirement) and the tolerance of microorganisms to the toxicant. ρ is equal to 0.9 for the case of Cd in batch test and 0.6 in continuous test. The theory in this study provides generally good estimations to the dose‐response relationship at limiting nutrient conditions. The study indicate that nutrient conditions constitute an important factor in algal toxicity tests.     

双酚A促进粪肠球菌中信息素调控质粒pCF10介导的耐药基因接合转移

粪肠球菌是一种在自然水体中广泛存在的革兰氏阳性细菌。信息素调控质粒介导的接合转移是造成粪肠球菌耐药基因快速扩散的重要方式。双酚A是一种内分泌干扰物,因其在工业中大量应用造成其在水环境中的广泛分布。本文以信息素调控质粒中比较有代表性的pCF10质粒作为研究对象,研究了双酚A对粪肠球菌中耐药基因接合转移的影响,证实了双酚A可以促进pCF10质粒介导的耐药基因接合转移,且这一结果同双酚A作用浓度和作用时间相关。双酚A影响耐药基因的扩散,是通过促进编码正调控信息素的ccfA基因表达实现的。本文旨在深入理解双酚A影响抗生素抗性基因扩散的环境行为,为耐药基因控制及双酚A环境效应的评估提供理论支持。     

不同部位梧桐生物质炭对水溶液中镉吸附的机理

为了探究梧桐不同部位废弃物所制备的生物质炭(皮、枝、叶)对Cd²⁺的吸附效率和稳定修复的机理,以此为园林废弃物炭化利用在重金属污染修复方面的应用提供科学依据.利用实验室模拟法,通过高温煅烧法制备梧桐不同部位生物质炭,采用元素分析仪、比表面积及孔隙分析(BET)、X射线衍射仪(XRD)、扫描电镜/能谱(SEM/EDS)及衰减全反射红外光谱(ATR-IR)等技术研究不同反应时间、重金属浓度和溶液初始pH条件下生物质炭对Cd²⁺吸附效果的影响,并运用四步萃取法和脱附实验分析生物质炭上Cd²⁺的吸附形态和稳定性.3种生物质炭都在8 h左右达到吸附平衡,最终吸附量依次为树皮炭>枝条炭>叶片炭;溶液初始浓度为0.5—2 g·L^-1时Cd²⁺的吸附量呈增长趋势,在2.5—3g·L^-1时逐渐平缓;生物质炭Cd²⁺吸附量均随着pH的升高而升高,但在pH值为5—8时,吸附的趋势逐渐平稳;树皮炭的酸溶态和非生物利用态的稳定Cd形态要高于枝条炭和叶片炭;比表面积不是影响梧桐生物质炭吸附Cd²⁺的主要影响因素,吸附动力学,ATR,XRD和重金属形态萃取均证实Cd碳酸盐类矿物生成是主导吸附机理;3种生物质炭的脱附量在4 h后逐渐趋于平衡,其中脱附量最大为叶片炭,最小为树皮炭.梧桐不同部位的初始性质对生物质炭吸附Cd²⁺具有明显的影响,其中梧桐皮具备更高的吸附量和重金属稳定形态,并且相比其他种类生物质炭有明显优势.因此,从吸附效果和生产成本的角度,本研究建议以梧桐皮为主,枝条和叶片为辅的生物质炭对重金属Cd进行修复治理.