农闲期城郊农田灌溉水中典型污染物含量与评价——以西北江三角洲为例

摸查了农田灌溉系统水环境经农（夏）闲期降水等外部强干预调理后的环境污染物含量——该值理论上是环境自净作用之后的最不利值,对农田灌溉系统水环境进行水质评价,探究其对农田土壤质量的潜在污染风险.于2019年6月中旬—7月下旬（降雨集中期）,分别在西北江三角洲城市（清远市、佛山市和江门市）实验基地周边筛选研究区,并在雨后对有覆水的水源区域、灌渠、蓄水池和田间水等采集上覆水,共采得水样27×2份,对其pH值、悬浮物（SS）、矿化度、总磷（TP）、氨氮（NH₄⁺-N）、Cd、As、Pb、Cu和Zn的含量进行检测;对各研究区pH值、SS的成因和影响,矿化度的等级,重金属均值分布等进行分析;对全样品TP、NH₄⁺-N、重金属含量进行Pearson相关性分析和描述性特征分析;通过单因子水质标识指数P_i和综合水质标识指数P分别对各采样点、各构成项目和各研究区进行水质评价.研究发现雨后农田灌溉系统水环境构成复杂,物质呈无显著性差异的迁移,灌溉沿程上覆水中大部分物质可能处于动态平衡,受局部环境影响变小,TP、NH₄⁺-N和重金属等迁移物质主要还是灌溉水体中原有的,受外力驱动扰动后在水动力作用下可能以氮磷结合形态沿灌溉系统发生远距离迁移;使用河流水质标识指数法评价农田灌溉系统水环境,发现该法可以刻画局部灌溉的水质态势,对农田灌溉系统水环境的含量特征评价做出科学、合理的解释,也可以做出综合性定量评价.虽然灌溉水系统结构差异较大,但是从整体上可以初步得出农闲期西北江三角洲农田灌溉水的灌溉风险不高的结论,总体综合水质评价级别为Ⅰ类~Ⅱ类,达到水环境功能区的使用要求.     

开远市生态——经济规划研究

开远市生态—经济规划研究总体设计分为三个研究层次，第一层次是总体发展战略研究，采用系统动力学方法进行总体模拟分析，具体研究发展战略、现行政策和未来发展的总体规划方案的趋势分析和比较，并用综合评价法模型优选总体规划方案。第二层次是环境与经济发展研究，采用投入———产出法研究经济发展的投入产出和排污水平、环境与经济调发展的宏观对策，制定实施污染物总量控制的环境综合治理规划。第三层次是研究优势资源的开发利用和生态环境的保护关系，谋求开远市经济与环境协调、稳定和持续发展、实现经济、社会和环境效益的统一。     

Insights into reactive oxygen species formation induced by water-soluble organic compounds and transition metals using spectroscopic method

Ambient particulate matter (PM) can cause adverse health effects via their ability to produce Reactive Oxygen Species (ROS). Water-Soluble Organic Compounds (WSOCs), a complex mixture of organic compounds which usually coexist with Transition Metals (TMs) in PM, have been found to contribute to ROS formation. However, the interaction between WSOCs and TMs and its effect on ROS generation are still unknown. In this study, we examined the ROS concentrations of V, Zn, Suwannee River Fulvic Acid (SRFA), Suwannee River Humic Acid (SRHA) and the mixtures of V/Zn and SRFA/SRHA by using a cell-free 2′,7′-Dichlorodihydrofluorescein (DCFH) assay. The results showed that V or Zn synergistically promoted ROS generated by SRFA, but had an antagonistic effect on ROS generated by SRHA. Fluorescence quenching experiments indicated that V and Zn were more prone to form stable complexes with aromatic humic acid-like component (C1) and fulvic acid-like component (C3) in SRFA and SRHA. Results suggested that the underlying mechanism involving the fulvic acid-like component in SRFA more tending to complex with TMs to facilitate ROS generation through π electron transfer. Our work showed that the complexing ability and complexing stability of atmospheric PM organics with metals could significantly affect ROS generation. It is recommended that the research deploying multiple analytical methods to quantify the impact of PM components on public health and environment is needed in the future.     

Starch, Poly(lactic acid), and Poly(vinyl alcohol) Blends

Research on biodegradable materials has been stimulated due to concern regarding the persistence of plastic wastes. Blending starch with poly(lactic acid) (PLA) is one of the most promising efforts because starch is an abundant and cheap biopolymer and PLA is biodegradable with good mechanical properties. Poly(vinyl alcohol) (PVOH) contains unhydrolytic residual groups of poly(vinyl acetate) and also has good compatibility with starch. It was added to a starch and PLA blend (50:50, w/w) to enhance compatibility and improve mechanical properties. PVOH (M_W 6,000) at 10%, 20%, 30%, 40%, 50% (by weight) based on the total weight of starch and PLA, and 30% PVOH at various molecular weights (M_W 6,000, 25,000, 78,000, and 125,000 dalton) were added to starch/PLA blends. PVOH interacted with starch. At proportions greater than 30%, PVOH form a continuous phase with starch. Tensile strength of the starch/PLA blends increased as PVOH concentration increased up to 40% and decreased as PVOH molecular weight increased. The increasing molecular weight of PVOH slightly affected water absorption, but increasing PVOH concentration to 40% or 50% increased water absorption. Effects of moisture content on the starch/PLA/PVOH blend also were explored. The blend containing gelatinized starch had higher tensile strength. However, gelatinized starch also resulted in increased water absorption.     

新疆生态环境保护法律问题研究

通过对新疆地区生态环境及其法制建设现状进行分析,发现新疆地区的法制现状不容乐观,环境立法与执法不能完全适应经济社会可持续发展的要求。鉴于此,结合区情对所存在的问题提出生态环境保护的法制构想,以期推动区域经济、社会和环境的协调发展。     

厌氧发酵系统中回流沼液的产甲烷活性研究

为确定两阶段厌氧发酵系统合理的污泥回流时段,对厌氧发酵系统排出沼液产甲烷活性进行了研究。通过对这些沼液在后储罐放置的不同天数(0~5 d)测定其不同的活性,用间歇实验方法测定最大比产甲烷活性(Um ax.CH4)作为厌氧污泥的产甲烷活性指标。结果表明,排出的沼液产甲烷活性在不同的时间段有所不同,经实验得出沼液放置第2 d时的产甲烷活性最高,从而确定该两阶段厌氧发酵系统排出污泥合理的回流时段应该是沼液进入后储罐的第2 d。进而为在线活性污泥与后储罐最佳活性时段污泥混合的污泥回流工艺提供理论依据。     

临夏盆地13.0~4.3 Ma湖相沉积物中正构脂肪酮记录的古气候演化

本文主要采用气相色谱-质谱分析技术对临夏盆地13.0~4.3 Ma沉积地层剖面样品进行检测,根据样品中正构烷烃、正构脂肪酮-2和正构脂肪酮-3的分布特征,揭示了正构脂肪酮对环境气候的指示意义。正构脂肪酮-2、正构脂肪酮-3与正构烷烃具有相同的有机质来源。其中正构脂肪酮-2的C₂₁^-/C₂₂⁺及正构脂肪-3-酮的C₂₁^-/C₂₃⁺比值变化与地质历史时期的气候与环境条件具有较好的相关性,对环境温度及湿度等变化有一定的指示意义。正构脂肪酮-2、正构脂肪酮-3的高、低碳数优势的转化指示研究区在13.0~4.3 Ma间的古气候具有四个较为明显的变化阶段,其中10.77~9.42 Ma、7.17~6.92 Ma气候由干冷变为暖湿,9.42~7.17 Ma、6.92~6.45 Ma气候由暖湿变为干冷,临夏盆地的干旱化事件指示了我国西北内陆现代干旱气候可能从8 Ma左右开始。     

非饱和土壤轻油污染多相流研究进展

轻油泄漏到地下后 ,在非饱和土壤中水、气、油三相相互作用、相互影响 ,共同构成多相流体系统。在简要分析轻油污染问题的产生、危害以及轻油泄漏在地表以下运移方式的基础上 ,介绍并总结了近些年来国内外土壤轻油污染有关的多相流研究方面的进展 ,包括国外的模型研究成果、国内外试验研究方法和研究成果 ,并指出目前研究中存在的问题和需要进一步探讨的方向     

Remediation of 2,4-dichlorophenol-contaminated groundwater using nano-sized CaO2 in a two-dimensional scale tank

• Nano CaO₂ is evaluated as a remediation agent for 2,4-DCP contaminated groundwater. • 2,4-DCP degradation mechanism by different Fe²⁺ concentration was proposed. • 2,4-DCP was not degraded in the system for solution pH>10. • The 2,4-DCP degradation area is inconsistent with the nano CaO₂ distribution area. This study evaluates the applicability of nano-sized calcium peroxide (CaO₂) as a source of H₂O₂ to remediate 2,4-dichlorophenol (2,4-DCP) contaminated groundwater via the advanced oxidation process (AOP). First, the effect and mechanism of 2,4-DCP degradation by CaO₂ at different Fe concentrations were studied (Fenton reaction). We found that at high Fe concentrations, 2,4-DCP almost completely degrades via primarily the oxidation of •OH within 5 h. At low Fe concentrations, the degradation rate of 2,4-DCP decreased rapidly. The main mechanism was the combined action of •OH and O₂^•−. Without Fe, the 2,4-DCP degradation reached 13.6% in 213 h, primarily via the heterogeneous reaction on the surface of CaO₂. Besides, 2,4-DCP degradation was significantly affected by solution pH. When the solution pH was>10, the degradation was almost completely inhibited. Thus, we adopted a two-dimensional water tank experiment to study the remediation efficiency CaO₂ on the water sample. We noticed that the degradation took place mainly in regions of pH<10 (i.e., CaO₂ distribution area), both upstream and downstream of the tank. After 28 days of treatment, the average 2,4-DCP degradation level was ≈36.5%. Given the inadequacy of the results, we recommend that groundwater remediation using nano CaO₂: (1) a buffer solution should be added to retard the rapid increase in pH, and (2) the nano CaO₂ should be injected copiously in batches to reduce CaO₂ deposition.     

用14C示踪技术研究摇蚊幼虫对农药的富集作用

摇蚊幼虫是淡水湖泊中分布广泛、数量极大的底栖动物。它们生活在底泥中,位移能力很小,个体又较大,被认为是水质监测和生态毒理学研究的理想生物。底栖动物能大量富集水中微量的有毒物质,这已有许多报道,而有关摇蚊幼虫富集底泥中的有毒物质的报道甚少,国内至今尚未见报道。摇蚊幼虫富集毒物与其它底栖动物比较,其生态学意义更大,因为摇蚊幼虫除了作为鱼饵通过水生食物链浓缩和转移毒物外,大量的幼虫终将羽化为成虫,一批批飞离水体,有毒物质有可能较快地被消除掉。