气相色谱法测定长江水体悬浮物和沉积物中有机氯农药的残留量

采用GC/MS定性 ,GC/ECD定量 ,对长江南京段悬浮物和沉积物中 8种有机氯农药 (OCPs)进行了分离测定 ,结果表明悬浮物中OCPs的含量分布按DDTs>HCB HCHs的顺序减小 ,DDTs的含量为 0 5 2— 1 15ng·L-1,HCB及HCHs的含量分别为 0 11— 0 48ng·L-1和 0 14— 0 47ng·L-1.沉积物中OCPs的含量分布按DDTs >HCB >HCHs的顺序减小 ,DDTs的含量为 0 2 1— 4 5 0ng·g-1,HCB及HCHs的含量分别为 0 14— 3 96ng·g-1和 0 18— 1 6 7ng·g-1.但总的来说 ,长江悬浮物和沉积物中有机氯农药在各采样点的分布特征较相似 .     

脱水污泥热调质的特性

热调质方法是污泥深度脱水的有效办法之一。研究结果表明,污泥热调质过程中反应温度和反应时间对污泥热调质效果影响较大,搅拌速度影响较小。当反应温度从160℃升至180℃,反应时间从30 min增至60 min时,污泥溶液中挥发性悬浮固体(VSS)急剧溶解,释放出细胞里的结合水,表明污泥细胞破壁的温度条件为160～180℃,时间条件为45～60 min。热调质后污泥的比阻变化较大。随着反应温度的不断提高,比阻不断减小,污泥的脱水性能越来越好。实验确定了污泥热调质的最佳反应条件为:反应温度180℃,反应时间60 min,搅拌转速30 r/min。在此条件下,压滤后泥饼含水率约50%,滤液中COD浓度可达19 000 mg/L,有利于后续污泥的消化。     

反复扰动下磷在沉积物和悬浮物以及上覆水间的交换

以太湖梅梁湾和月亮湾沉积物为研究对象,分析了沉积物反复扰动下磷在沉积物、悬浮物、上覆水间的交换规律.结果表明,反复扰动下,上覆水中TP和PP浓度降低;DTP则是在第8 d达到平衡浓度,分别稳定在0.019 mg·L-1(梅梁湾)和0.039 mg·L-1(月亮湾);DIP则发生了释放,随后降低,DIP的释放主要与沉积物中NH4Cl-P含量最大有关.第8 d达到平衡浓度,分别稳定在0.013 mg·L-1(梅梁湾)和0.028 mg·L-1(月亮湾).与上覆水中溶解氧的变化规律吻合.另外,扰动过程中梅梁湾上覆水DTP和DIP均明显高于月亮湾.由于扰动作用,悬浮物和沉积物上不同形态磷(NH4Cl-P、Fe/Al-P、HCl-P)数量分布发生明显变化.扰动过程中,梅梁湾悬浮物上NH4Cl-P、Fe/Al-P、HCl-P含量逐渐降低,而同一时间段上覆水中不同形态磷含量同样降低,但沉积物上NH4Cl-P、Fe/Al-P、HCl-P含量逐渐增加.尽管月亮湾的趋势不如梅梁湾显著,但总体趋势一致,暗示悬浮物在磷交换过程中所起的媒介作用.     

太湖真光层深度谱的分布特征及其介质影响探究

基于2010年5月份全湖28个站点分层测量的水体下行辐照度以及各光学介质(有机悬浮物LOI、无机悬浮物ISS、叶绿素a Chl-a)浓度的实测数据,本文运用岭回归分析法,分析了不同湖区5月份真光层深度谱的分布特征及其影响因素.结果表明整个有效光合辐射范围内,3种因素对真光层深度的贡献均为负,ISS浓度是真光层深度的主要贡献因子,贡献率达0.48~0.62;其次为LOI浓度,贡献率为0.34~0.45;Chl-a浓度的贡献最小,贡献率为0.05~0.09.675 nm处,ISS的贡献具有谷值,Chl-a与LOI的贡献却为峰值;520~650 nm处Chl-a贡献值保持低值.此外,按各采样点的真光层深度谱分布的线型向量空间余弦相似度(cosine)进行分步聚类(Ascending Hierarchical),将全湖分为二类,梅梁湾、竺山湾、贡湖湾以及胥口湾以北区域为第一类,其余区域为第二类.结合全湖所有采样点的各介质浓度数据,发现第一类采样点LOI与Chl-a的相对浓度大于第二类,此两类介质浓度凸显了650 nm、675 nm处真光层深度谱分布曲线的波谷特征.     

黄河流域氮磷营养盐动态特征及主要影响因素

收集了黄河流域下游主要干流监测站近40a来(氮数据)或20a(磷数据)来的水质数据,同时,收集了流域各省人口、氮肥磷肥施用量(折纯)及工业废水排放量等数据,研究了黄河氮磷营养盐通量(或浓度)的多年变化趋势,并统计了水质变化与流域人口、化肥用量和工业废水排放量等社会经济指标的关系.结果表明,黄河氮输送通量近40a来有不断升高的趋势,但1990s后期受黄河断流影响有明显下降;同时,由于下游引黄灌区大量取水使得花园口-利津之间的氮通量相对入海口的氮通量为负值.黄河总磷含量在一定范围内波动,没有呈现趋势性变化,受断流影响1990s后期总磷含量值也明显减小.进一步分析表明,黄河氮输送通量的变化主要受流域内人口、氮肥施用量的影响,而与工业废水排放量没有统计上的相关性;黄河总磷含量和流域人口、磷肥施用量和废水排放量均无相关性,而与黄河水体中悬浮物含量显著相关.回归分析结果表明,黄河水体悬浮物中的总磷含量为0.54g·kg-1,与黄土高原总磷背景值十分接近.由于黄河悬浮物主要来自黄土高原,故判断黄河总磷输送的主要影响因素是黄土高原的水土流失.查明黄河流域氮磷输送量多年变化情况和主要影响因素可为流域和海域污染控制及负荷分配提供依据.     

Natural and anthropogenic contamination of the Fratta-Gorzone river (Veneto, Italy)

Stream-bed sediment samples were collected in 2001 and 2004 along the Fratta-Gorzone River (Italy) to assess the level of heavy metal contamination. The river stretch most affected by discharges of tannery effluent showed total and pseudo-total Cr levels (up to 2,860 mg/kg) that greatly exceed national and international chemical sediment quality standards. The most contaminated section of the river bed is located downstream of the main industrial discharge. However, a large fraction of the Cr present in the sediment appears to be of lithogenic origin. At most sites, more than 50% of Cr is not soluble in aqua-regia and thus unlikely to be very mobile or easily bio-available. A negligible risk to the benthic community can be inferred for Pb, Zn, Cd, Cu and Ni. This work highlights the limitation of using existing chemical sediment quality standards alone for risk assessment. The collection and analysis of suspended solids, the determination of river discharge and of dissolved Cr at 10 field stations allowed to estimate the particulate and dissolved Cr load and to locate the river stretch that was the likely source of contaminated sediment. The pumping of dilution water from the Adige River into the Fratta-Gorzone River did not produce the expected contaminant dilution effect due to re-suspension of contaminated solid particles and the release of Cr in solution.     

Modeled Sources,Transport, and Accumulation of Dissolved Solids in Water Resources of the Southwestern United States1

Anning, David W., 2011. Modeled Sources, Transport, and Accumulation of Dissolved Solids in Water Resources of the Southwestern United States. Journal of the American Water Resources Association (JAWRA) 47(5):1087‐1109. DOI: 10.1111/j.1752‐1688.2011.00579.x Abstract: Information on important source areas for dissolved solids in streams of the southwestern United States, the relative share of deliveries of dissolved solids to streams from natural and human sources, and the potential for salt accumulation in soil or groundwater was developed using a SPAtially Referenced Regressions On Watershed attributes model. Predicted area‐normalized reach‐catchment delivery rates of dissolved solids to streams ranged from <10 (kg/year)/km² for catchments with little or no natural or human‐related solute sources in them to 563,000 (kg/year)/km² for catchments that were almost entirely cultivated land. For the region as a whole, geologic units contributed 44% of the dissolved‐solids deliveries to streams and the remaining 56% of the deliveries came from the release of solutes through irrigation of cultivated and pasture lands, which comprise only 2.5% of the land area. Dissolved‐solids accumulation is manifested as precipitated salts in the soil or underlying sediments, and (or) dissolved salts in soil‐pore or sediment‐pore water, or groundwater, and therefore represents a potential for aquifer contamination. Accumulation rates were <10,000 (kg/year)/km² for many hydrologic accounting units (large river basins), but were more than 40,000 (kg/year)/km² for the Middle Gila, Lower Gila‐Agua Fria, Lower Gila, Lower Bear, Great Salt Lake accounting units, and 247,000 (kg/year)/km² for the Salton Sea accounting unit.     

湖泊沉积物短时间反复扰动下悬浮物上生物有效磷的动态变化

以太湖梅梁湾、月亮湾的沉积物和上覆水为材料,研究了较短时间尺度和沉积物反复扰动条件下,悬浮物中不同形态生物有效磷数量分布的变化特征.结果表明,随着扰动次数的增加,上覆水中藻类可利用磷(AAP)占溶解态总磷(DTP)的百分比均有所降低.试验期间,悬浮物中弱吸附态磷(NH4Cl-P)、可被生物利用颗粒态磷(BAPP)占总磷(Tot-P)的百分比平均值分别增加了3.5%、37.3%(梅梁湾)和2.0%、50.7%(月亮湾).梅梁湾悬浮物上AAP含量及其占Tot-P的百分比随扰动次数增加而增加,月亮湾则恰好相反.扰动期间,悬浮物上BAPP含量始终大于NH4Cl-P和AAP之和,表明BAPP的80%是由NH4Cl-P和AAP组成的.这也暗示了,仅仅以悬浮物中NH4Cl-P、AAP来估算BAPP存在一定的不合理性.     

黄河泥沙中的腐殖质对高锰酸盐指数测定的影响

通过模拟试验研究了黄河泥沙对高锰酸盐指数的影响,结果表明:①浑水高锰酸盐指数(COD_Mn)和水样加酸处理后水相COD_Mn随着泥沙含量的增加而显著增长;但水样未加酸处理水相的COD_Mn随着泥沙含量的增加只呈微上升趋势;②随着泥沙含量的增加,浑水生化需氧量(BOD₅)的增长率显著低于浑水COD_Mn和加酸处理条件下的水相COD_Mn的增长率;③黄土中含量仅为0.76%的腐殖质对含泥沙浑水COD_Mn的贡献较大,当泥沙含量为7.5g/L和15g/L时,腐殖质对浑水COD_Mn的贡献分别为15.9%和 21.7%;④泥沙中腐殖质的主要组成之一富里酸溶于酸,当泥沙含量为7.5g/L和15g/L时,富里酸对水样加酸处理后水相COD_Mn的贡献分别为23.6%和50.6%.由于富里酸在自然条件下不容易发生生物降解,因此,目前黄河水质监测中的COD_Mn夸大了黄河耗氧性有机物的污染.     

Parameters affecting the stability of the digestate from a two-stage anaerobic process treating the organic fraction of municipal solid waste

This paper focused on the factors affecting the respiration rate of the digestate taken from a continuous anaerobic two-stage process treating the organic fraction of municipal solid waste (OFMSW). The process involved a hydrolytic reactor (HR) that produced a leachate fed to a submerged anaerobic membrane bioreactor (SAMBR). It was found that a volatile solids (VS) removal in the range 40-75% and an operating temperature in the HR between 21 and 35 °C resulted in digestates with similar respiration rates, with all digestates requiring 17 days of aeration before satisfying the British Standard Institution stability threshold of 16 mg CO₂ g VS⁻¹ day⁻¹. Sanitization of the digestate at 65 °C for 7 days allowed a mature digestate to be obtained. At 4 g VS L⁻¹ d⁻¹ and Solid Retention Times (SRT) greater than 70 days, all the digestates emitted CO₂ at a rate lower than 25 mg CO₂ g VS⁻¹ d⁻¹ after 3 days of aeration, while at SRT lower than 20 days all the digestates displayed a respiration rate greater than 25 mg CO₂ g VS⁻¹ d⁻¹. The compliance criteria for Class I digestate set by the European Commission (EC) and British Standard Institution (BSI) could not be met because of nickel and chromium contamination, which was probably due to attrition of the stainless steel stirrer in the HR.