淀山湖沉积物碳-氮垂直分布特征

近年来,经过一系列污染治理措施,淀山湖的营养水平持续下降,但每年仍有不同程度的蓝藻水华暴发,严重影响其作为水源地的安全性。为了进一步探讨淀山湖水质改善策略,本研究对淀山湖沉积物营养状况进行了调查研究,分析了淀山湖沉积物碳、氮分布特征及垂直变化规律,并用沉积物肥力评价了淀山湖沉积物营养程度。结果表明,淀山湖沉积物营养盐存在明显的富集作用,二十多年来沉积物碳、氮含量大幅上升,表层沉积物均属于重污染状态。空间分布上,沉积物营养盐北部高,南部低,北部样点大部分属于重污染状态,南部样点基本属于中污染状态。垂直分布上,受航道回淤与北部围网养殖影响,部分样点营养盐垂直分布规律不显著,其他样点均表现出随深度增加营养盐显著降低的趋势。除出水口D1样点外,淀山湖有机质与TN表现出显著的同源相关性,表明有机质是淀山湖内源负荷的主要来源。     

挥发回转窑处置钢丝绳行业污泥的污染物排放研究

通过利用挥发回转窑处置钢丝绳行业污泥的工业化试验,测定了烟气排放参数及污染物排放指标,分析了污泥添加对挥发回转窑烟气排放的影响程度及各项污染物指标之间的相关性。结果表明,污泥添加量18%～22%,对挥发回转窑烟气排放无影响,烟尘、SO2、氮氧化物、Zn、Pb、HCl等各项污染物指标均符合国家控制标准;烟尘排放浓度与Pb、Zn排放浓度呈显著正相关;SO2排放浓度与烟气含氧量、空气过剩系数、排放浓度呈显著负相关。通过控制烟气中烟尘浓度可减少Zn、Pb的排放,在满足SO2排放浓度达标的同时,还应加强工艺供氧量的管理,控制的产生,减少烟气对生产设备的腐蚀。     

挥发性有机废气治理技术进展

主要介绍了目前国内外有机废气（VOCs）治理的常用方法以及这些方法的原理和工艺流程,并对它们的特点进行了简单介绍。     

蒙脱石对有机物料施入土壤磷形态和有效性的影响

以冷砂黄泥和矿子黄泥为研究对象,猪粪沼渣为有机物料,分别添加0%、5%、7.5%和10%质量分数的蒙脱石,采用室内培养试验研究了蒙脱石对施有机物料土壤pH、磷形态和有效性的影响.结果表明,有机物料对两种土壤pH无显著影响,而蒙脱石使土壤pH显著提高.施加有机物料使两种土壤铝结合态磷(Al-P)含量和分布比例提高,铁结合态磷(Fe-P)含量培养后期提高、比例略有下降,闭蓄态磷(O-P)含量无明显变化、比例下降.有机物料对冷砂黄泥中钙结合态磷(Ca-P)的含量无明显影响、比例下降,却使矿子黄泥Ca-P含量和比例提高.在施加有机物料基础上添加蒙脱石后,冷砂黄泥Al-P和O-P含量和比例下降,Fe-P含量无明显变化、比例下降,Ca-P含量和比例大幅度提高;矿子黄泥Fe-P和O-P含量和比例下降,Al-P含量无明显变化、比例下降,Ca-P含量和比例大幅度提高.培养过程中,有机物料使冷砂黄泥和矿子黄泥有效磷含量分别提高了17.9%~38.0%和17.1%~33.7%,土壤磷的活化系数也显著提高,添加蒙脱石后使两种土壤有效磷含量分别降低8.8%~35.5%和1.1%~11.6%.相关分析结果表明,蒙脱石通过提高pH和Ca-P含量、降低Al-P含量降低冷砂黄泥磷的有效性,通过提高pH、降低Fe-P含量降低矿子黄泥磷的有效性,对冷砂黄泥磷有效性的影响较矿子黄泥大.     

岩溶地下河系统中有机氯的分布特征与来源分析

选取重庆老龙洞、青木关岩溶地下河为研究对象,采用气相色谱仪-微池电子捕获检测器(GC-μECD)分析两条地下河水体中21种有机氯农药(OCPs)的浓度.结果表明,南山地下河中六六六(HCHs)和艾氏剂类化合物(ALDs)是主要检出物,青木关地下河中HCHs和甲氧滴滴涕是主要检出物.南山、青木关地下河中均未检出o,p'-DDE、p,p'-DDE、o,p'-DDD,同时,青木关地下河还未检出o,p'-DDT、狄氏剂,其余OCPs在两条地下河中检出率高达100%.青木关地下河中OCPs浓度范围为145~278 ng·L-1之间,平均值为213 ng·L-1;南山老龙洞地下河中OCPs浓度介于17.7~40.8 ng·L-1之间,平均值为32.7ng·L-1.两条地下河中各OCPs组分表现为地下河出口大于入口.通过对OCPs污染来源分析,发现两地下河流域滴滴涕(DDTs)主要来自于历史上工业DDTs输入,氯丹主要来自于大气沉降.六六六(HCHs)主要来源是林丹的输入,南山地下河属于历史污染,青木关地下河上游的甘家槽有新的HCHs输入.与国内外其他各水体相比,南山地下河水体中HCHs、DDTs浓度处于低水平;青木关下河处于中等偏高水平.结合中外用水卫生标准,发现南山地下河和青木关地下河未超过饮水安全标准.青木关应禁止农田施用有机氯农药,保护地下河生态环境.     

Beyond hypoxia：Occurrence and characteristics of black blooms due to the decomposition of the submerged plant Potamogeton crispus in a shallow lake

Organic matter-induced black blooms(hypoxia and an offensive odor) are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate black blooms that were induced by Potamogeton crispus in Lake Taihu, China. The main physical and chemical characteristics, including color- and odor-related substances, of the black blooms were analyzed. The black blooms were characterized by low dissolved oxygen concentration(close to 0 mg/L), low oxidation-reduction potential, and relatively low pH of overlying water. Notably higher Fe2+and∑S2-were found in the black-bloom waters than in waters not affected by black blooms. The black color of the water may be attributable to the high concentration of these elements, as black FeS was considered to be the main substance causing the black color of blooms in freshwater lakes. Volatile organic sulfur compounds, including dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, were very abundant in the black-bloom waters. The massive anoxic degradation of dead Potamogeton crispus plants released dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, which were the main odor-causing compounds in the black blooms. The black blooms also induced an increase in ammonium nitrogen and soluble reactive phosphorus levels in the overlying waters. This extreme phenomenon not only heavily influenced the original lake ecosystem but also greatly changed the cycling of Fe, S, and nutrients in the water column.     

Compositions and sources of organic acids in fine particles (PM2.5) over the Pearl River Delta region, south China

Organic acids as important constituents of organic aerosols not only influence the aerosols' hygroscopic property, but also enhance the formation of new particles and secondary organic aerosols. This study reported organic acids including C14–C32fatty acids, C4–C9dicarboxylic acids and aromatic acids in PM2.5collected during winter 2009 at six typical urban, suburban and rural sites in the Pearl River Delta region. Averaged concentrations of C14–C32fatty acids, aromatic acids and C4– C9 dicarboxylic acids were 157, 72.5 and 50.7 ng/m3, respectively. They totally accounted for 1.7% of measured organic carbon. C20–C32fatty acids mainly deriving from higher plant wax showed the highest concentration at the upwind rural site with more vegetation around, while C14–C18fatty acids were more abundant at urban and suburban sites, and dicarboxylic acids and aromatic acids except 1,4-phthalic acid peaked at the downwind rural site. Succinic and azelaic acid were the most abundant among C4–C9dicarboxylic acids, and 1,2-phthalic and 1,4-phthalic acid were dominant aromatic acids. Dicarboxylic acids and aromatic acids exhibited significant mutual correlations except for 1,4-phthalic acid, which was probably primarily emitted from combustion of solid wastes containing polyethylene terephthalate plastics. Spatial patterns and correlations with typical source tracers suggested that C14–C32fatty acids were mainly primary while dicarboxylic and aromatic acids were largely secondary. Principal component analysis resolved six sources including biomass burning, natural higher plant wax, two mixed anthropogenic and two secondary sources; further multiple linear regression revealed their contributions to individual organic acids. It turned out that more than 70% of C14–C18fatty acids were attributed to anthropogenic sources, about 50%–85% of the C20–C32fatty acids were attributed to natural sources, 80%–95% of dicarboxylic acids and 1,2-phthalic acid were secondary in contrast with that 81% of 1,4-phthalic acid was primary.     

Fouling distribution in forward osmosis membrane process

Fouling behavior along the length of membrane module was systematically investigated by performing simple modeling and lab-scale experiments of forward osmosis （FO） membrane process. The flux distribution model developed in this study showed a good agreement with experimental results, validating the robustness of the model. This model demonstrated, as expected, that the permeate flux decreased along the membrane channel due to decreasing osmotic pressure differential across the FO membrane. A series of fouling experiments were conducted under the draw and feed solutions at various recoveries simulated by the model. The simulated fouling experiments revealed that higher organic （alginate） fouling and thus more flux decline were observed at the last section of a membrane channel, as foulants in feed solution became more concentrated. Furthermore, the water flux in FO process declined more severely as the recovery increased due to more foulants transported to membrane surface with elevated solute concentrations at higher recovery, which created favorable solution environments for organic adsorption. The fouling reversibility also decreased at the last section of the membrane channel, suggesting that fouling distribution on FO membrane along the module should be carefully examined to improve overall cleaning efficiency. Lastly, it was found that such fouling distribution observed with co-current flow operation became less pronounced in counter- current flow operation of FO membrane process.     

土地利用变化对土壤有机碳的影响研究进展

研究土地利用变化对土壤有机碳及其动态变化规律,有助于掌握全球气候变化与土地利用变化之间的关系。本文分别从土地利用及其管理方式变化的角度,综合阐述了土地利用变化对土壤有机碳的影响过程与机理。     

重金属抗性解磷细菌的磷溶解特性研究

从湖南省湘西州花垣县的铅锌矿表层土壤中,筛选出两株具有重金属抗性和解磷特性的细菌T PSB1和T PSB2.通过16S rRNA基因序列比对,分别鉴定为嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia)和唐菖蒲伯克霍尔德菌(Burkholderia gladioli).T PSB1和T PSB2在含有难溶性无机磷液体培养基中,其上清液的可溶性磷含量最高分别达到了402.9 mg·L-1和589.9 mg·L-1;在难溶性有机磷固体和液体培养基中,固体平板上均出现解磷圈,而液体培养基上清液中,可溶性磷含量也分别达到了2.97 mg·L-1和4.69 mg·L-1.另外,两株细菌对重金属Zn2+的抗性最高,在其浓度为2000 mg·L-1固体和液体培养基条件下均可以生长,磷溶解浓度分别为114.8 mg·L-1和125.1 mg·L-1.而在含铬和铅的浓度为1 000 mg·L-1的液体培养基中,两株细菌同样表现出重金属抗性.在Pb2+浓度为1000 mg·L-1的液体培养基中,磷溶解浓度分别达到了57.9 mg·L-1和71.7 mg·L-1;而在Cr2+浓度为1000 mg·L-1的培养基中磷溶解浓度分别为60.1 mg·L-1和98.4 mg·L-1.