公共资源类旅游景区水环境承载力研究 ——以武汉市东湖风景区为例

公共资源类旅游景区水环境受到社会经济系统和旅游系统两方面影响,本文通过选取人口、GDP、灌溉面积、游客量、宾馆日接待人数、TP、COD、BOD等指标,构建水环境承载力多目标模型.同时,选取水果湖、汤菱湖和郭郑湖3个子湖对东湖风景区水环境承载力进行评价,并运用层次分析法(AHP)确定各指标对东湖风景区水环境承载力的权重,采用典型水环境承载力概念模型计算了2011年武汉市东湖风景区水环境承载力.结果表明,东湖风景区水资源承载力表现为灌溉面积和GDP承载度超标,而人口和旅游指标承载度未达到饱和,水质承载力各指标的承载度超标.水果湖、汤菱湖和郭郑湖的水环境承载力分别为4.03、3.86、3.95,均大大超出负荷.     

石灰与磷肥对籽粒苋吸收镉的影响

籽粒苋(Amaranthus hypochondriacus L.)是我国广泛栽种的牧草,但具有富集重金属Cd的特性,探讨减少其吸收镉的方法技术,可以降低人畜受害风险.研究利用温室盆栽方法,比较了施用磷肥和石灰对降低籽粒苋Cd吸收量的影响.于含镉5 mg·kg-1的污染菜园土中,以粉末形式加入3 g·kg-1 Ca(OH)2,或以液态形式加入磷肥(0.326 g·kg-1 Ca(H2PO4)2)至P浓度80 mg·kg-1,该施用量为农业应用常规水平.播种籽粒苋,于60 d后收获,测定相关参数.结果表明,施用石灰使土壤pH上升1.7单位,土壤有效Cd下降至极低水平,从而大幅降低籽粒苋Cd吸收量,较对照下降约56%,但施石灰也使土壤供磷量下降,使籽粒苋的生物量也减少了约一半.施用石灰后,土壤的Ca与K供应量以及籽粒苋体内Ca与K含量均明显增加,Ca、K与Cd形成的竞争吸收也是施用石灰后籽粒苋Cd含量下降的一个原因.本地菜同土含有较高的有效磷,以常规农业磷肥施用量施用磷肥对籽粒苋吸收Cd没有明显影响,对生物量也没有明显影响,但适当提高施用量预期会有一定的效果.因而,对广州地区菜园土,使用合理的石灰施用量,可有效降低籽粒苋Cd吸收量.     

我国南方主要酸沉降区土壤中铝的释放与缓冲作用

本文研究了我国南方酸沉降区主要土壤类型在模拟酸雨影响下淋溶液ｐＨ值及Ａｌ离子释放特点,结果表明,石灰土和滨海盐土的阳离子淋溶量低于阳离子交换量,土壤主要处于阳离子交换缓冲范围和碳酸盐－硅酸盐缓冲范围,Ａｌ释放量一般低于０．４０ｍｍｏｌ·ｋｇ＾－１。     

乙酸钙不动杆菌TS2H对DBP降解特性的研究

邻苯二甲酸酯(PAEs)是一类具有一般毒性和致畸、致突变性的有机化合物,它作为重要的化工原料被大量地用于塑料生产,同时也带来了严重的环境污染问题。文章以邻苯二甲酸二丁酯(DBP)为PAEs生物降解研究的模型物,通过驯化富集培养,分离出1株能降解DBP的乙酸钙不动杆菌(Acinetobacter calcoaceticus)TS2H,研究了TS2H对DBP的生物降解特性。结果表明,该菌可在好氧条件下高效降解DBP,在最佳pH值7时,150r·min-1振荡培养48h对DBP初始质量浓度为40mg·L-1的降解率可达到98.64%;TS2H对100mg·L-1内较高质量浓度的DBP均具有较高的降解效能,但当DBP质量浓度达到300mg·L-1时,降解效能受到一定的抑制;加入营养物蛋白胨能促进菌株TS2H对DBP的降解,而葡萄糖和苯甲酸钠的加入对DBP的降解有延缓作用;菌株TS2H在一定浓度的Zn2 、Cd2 和Cu2 条件下仍可较高效地降解DBP。     

Improvement of nitrification efficiency by bioaugmentation in sequencing batch reactors at low temperature

Bioaugmentation is an effective method of treating municipal wastewater with high ammonia concentration in sequencing batch reactors （SBRs） at low temperature （10℃）. The cold-adapted ammonia- and nitrite- oxidizing bacteria were enriched and inoculated, respectively, in the bioaugmentation systems. In synthetic wastewater treatment systems, the average NH4＋-N removal efficiency in the bioaugmented system （85%） was much higher than that in the unbioaugmented system. The effluent NH4＋ -N concentration of the bioaugmented system was stably below 8 mg. L1 after 20 d operation. In municipal wastewater systems with bioaugmentation, the effluent NH4＋- -N concentration was below 8 mg·L^-1 after 15 d operation. The average NH4＋ -N removal efficiency in unbioaugmentation system （about 82%） was lower compared with that in the bioaugmentation system. By inoculating the cold-adapted nitrite-oxidizing bacteria （NOB） into the SBRs after 10 d operation, the nitrite concentration decreased rapidly, reducing the NO2 -N accumulation effectively at low temperature. The func- tional microorganisms were identified by PCR-DGGE, including uncultured Dechloromonas sp., uncultured Nitrospira sp., Clostridium sp. and uncultured Thauera sp. The results suggested that the cold-adapted microbial agent of ammonia-oxidizing bacteria （AOB） and NOB could accelerate the start-up and promote achieving the stable operation of the low-temperature SBRs for nitrification.     

免水生物降解型生态厕所专用菌剂

针对免水生物降解型生态厕所专用的进口菌种成本偏高、不能长期高效运行等现状,从土壤中分离筛选得到6株降解菌并将其培养成1组复合菌,然后分别进行降解实验。结果表明,7组实验菌对人体排泄物降解效果良好,其中复合菌种更好,COD降解率达到59%。对实验菌种进行初步鉴定,显示6株菌分别是粪肠球菌、木糖葡萄球菌、蜡状芽孢杆菌、产氨棒杆菌、地衣芽孢杆菌和活动肉杆菌。优选的专用菌剂的制备及保存方法效果良好,保存半年后菌剂仍有较高活性。     

零价铁对土壤中对氯硝基苯的还原作用

在常温常压下,利用零价铁(Fe0)还原土壤中的对氯硝基苯(p-CNB),研究反应产物随时间的变化以及反应条件对还原率的影响.实验结果表明,Fe0能够有效将土壤中的p-CNB还原成对氯苯胺(p-CAN),反应过程中先生成中间产物对氯亚硝基苯(p-CNSB),然后再进一步还原生成p-CAN.p-CNB还原率受到反应时间,土壤初始pH、温度、铁粉用量和土壤含水率等条件的影响.当p-CNB约为2.5×10-6mol/g,土壤初始pH为6.8,铁粉用量为50 mg,土壤含水率为75%时,在恒温生化培养箱中温度为(25±1)℃条件下,反应5 h后p-CNB还原率达到97.43%.     

Tripolyphosphate-assisted electro-Fenton process for coking wastewater treatment at neutral pH

Environmental Science and Pollution Research - The first application of a novel electro-Fenton (EF) for coking wastewater (CW) treatment at the original pH (6.80) by using tripolyphosphate (TPP)...     

Comparison of mercury bioaccumulation between wild and mariculture food chains from a subtropical bay of Southern China

Bioaccumulation and trophic transfer of mercury (Hg) both in the natural marine ecosystem and the mariculture ecosystem were studied at Daya Bay, a subtropical bay in Southern China. Averaged Hg concentrations in sediment, phytoplankton, macrophyte, shrimp, crab, shellfish, planktivorous fish, carnivorous fish, farmed pompano, farmed snapper, compound feed and trash fish were 0.074, 0.054, 0.044, 0.098, 0.116, 0.171, 0.088, 0.121, 0.210, 0.125, 0.038 and 0.106 μg g⁻¹ dw, respectively. These Hg levels were at the low–middle ends of the global range. Positive correlation between Hg concentrations in farmed fish and fish weights/sizes was observed, whereas no clear correlation between Hg concentrations and lipid contents was found. Hg concentrations followed macrophyte < phytoplankton < sediment < planktivorous fish < shrimp < crab < carnivorous fish < shellfish, and commercial feed < trash fish < farmed fish. Hg was biomagnified along the marine food chain in the ecosystem of Daya Bay. Hg levels in the farmed fish were higher than those in the wild fish primarily because of the higher Hg level in fish feed and the smaller size of marine wild fish.