危险品道路运输泄漏引发水污染事故的定量风险评估方法研究

介绍了由道路交通事故引发的地表水污染事故风险定量分析方法,重点分析了突发水污染事故源发生概率和危害后果表征方法.以评价水域内道路危险品运输泄漏事故发生概率为水污染事故源发生概率.污染事故后果危害水平的表征:1)敏感区(点)最高浓度; 2)敏感区(点)超标总历时;3)水质超标的范围(如超标河流长度).评估方法为陆源造成的突发水污染事故的预防管理与应急计划的制订实施提供了科学依据.     

Concentrations and inventories of polycyclic aromatic hydrocarbons and organochlorine pesticides in watershed soils in the Pearl River Delta,China

The concentration levels, source, and inventories of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in 55 surface vegetable soils in the watershed of the Pearl River Delta (PRD) were analyzed and compared with those of the surface sediments in the Pearl River Estuary (PRE) and northern South China Sea (SCS). The 16 priority PAHs on US EPA list range from 58 to 3,077 microg/kg (average: 315 microg/kg). The concentrations of DDTs and HCHs range from 3.58 to 831 microg/kg (average: 82.1 microg/kg) and from 0.19 to 42.3 microg/kg (average: 4.42 microg/kg). The ratios of DDT/ (DDD+DDE) are higher than 2 in majority of the soil samples, suggesting that DDT contamination still exists. The PAH ratios suggest that the source of PAHs is petroleum, and combustion of fossil fuel, biomass, and coal. The average concentrations of PAHs and the linear regression slope between PAHs and TOC for the soils and the sediments are quite similar. It was estimated that the soil mass inventories at 0-20 cm depth are 1,292 metric tons for PAHs and 356 metric tons for OCPs in the studied region. The average PAHs inventory per unit area for the soil samples investigated in PRD is about 0.86 time that of surface sediments in the Pearl River Estuary, and about 2.43 times that of surface sediments in the northern South China Sea. PAHs in the soils in PRD have similar source to those of the surface sediments in PRE. All of those may suggest that PAHs in PRE and SCS are probably mainly inputted from the soils in PRD via soil erosion and river transport.     

Role of cosubstrate and bioaccessibility played in the enhanced anaerobic biodegradation of organochlorine pesticides (OCPs) in a paddy soil by nitrate and methyl-β-cyclodextrin amendments

The present study was conducted to investigate the anaerobic biodegradation potential of biostimulation by nitrate (KNO₃) and methyl-β-cyclodextrin (MCD) addition on an aged organochlorine pesticide (OCP)-contaminated paddy soil. After 180 days of incubation, total OCP biodegradation was highest in soil receiving the addition of nitrate and MCD simultaneously and then followed by nitrate addition, MCD addition, and control. The highest biodegradation of chlordanes, hexachlorocyclohexanes, endosulfans, and total OCPs was 74.3, 63.5, 51.2, and 65.1 %, respectively. Meanwhile, MCD addition significantly increased OCP bioaccessibility (p?<?0.05) evaluated by Tenax TA extraction and a three-compartment model method. Moreover, the addition of nitrate and MCD also obtained the highest values of soil microbial activities, including soil microbial biomass carbon and nitrogen, ATP production, denitrifying bacteria count, and nitrate reductase activity. Such similar trend between OCP biodegradation and soil-denitrifying activities suggests a close relationship between OCP biodegradation and N cycling and the indirect/direct involvement of soil microorganisms, especially denitrifying microorganisms in the anaerobic biodegradation of OCPs.     

自然灾害灾情划分指标研究

本文阐述了灾情分析中的两个基本方面，即损失的规模和损失的深度，提出了灾级和灾度的概念，对于影响灾级和灾度的主要指标也进行了分析。并就时间和空间变化对灾级划分界线的影响作了论述。     

生化法处理含氨废水动力学研究

对生化法处理含氨废水过去中有重要影响的动力学因素进行了试验研究和分析，得出了利用高效微生物菌群废水中COD和NH3－N的动力学条件，温度为20－35℃，PH为7－8，DO大于2.6mg/L,MLSS大于2.6g/L，C／N小于3。在此条件下处理含氨废水，处理后的出水达到国家化肥行业一级排放标准。     

油污土壤生物修复实验研究

为了有效预防和治理因石油开采、运输等造成的土壤污染,对大庆地区油污土壤进行了生物修复的实验研究,通过室内盆栽模拟实验,对芦苇和香蒲根际土壤的石油类污染物总含量、石油烃类组分浓度、非烃组分浓度进行了测定。结果表明,芦苇和香蒲对石油类污染物具有比较明显的降解作用,可以使被污染土壤中的某些油污成分逐渐被选择性消耗。实验还可看出,芦苇和香蒲对石油类污染物中正构烷烃的降解能力高于非正构烃。总体看,芦苇对石油类污染物的降解能力强于香蒲,但芦苇对非正构烃的降解能力略逊于香蒲。     

铜-磺胺嘧啶复合胁迫对蔬菜种子发芽的急性毒性效应

研究了黄潮土中常用兽药磺胺嘧啶(SD)与重金属铜(Cu)单一及复合污染对小白菜和西红柿种子发芽(发芽率、根伸长、芽伸长)的影响,分析了土壤中药物浓度与作物生长抑制的剂量-效应关系及复合污染的毒性效应。结果表明,无论是在Cu或SD单一污染物作用下,根伸长和芽伸长抑制率与污染物浓度显著相关(P0.01),发芽抑制率与污染物浓度不相关(P0.05);污染物对根伸长及芽伸长的抑制高于对种子发芽的抑制;SD对2种作物的毒性效应明显强于Cu,SD对小白菜和西红柿根伸长的ID50(抑制率为50%时污染物浓度)分别为1.7和33.6 mg·kg~(-1),而Cu为273.6和457.7 mg·kg~(-1)。Cu-SD复合污染,对西红柿的根和芽伸长的拮抗作用显著(P0.01);但对小白菜来说,在低浓度Cu(100 mg·kg~(-1))作用下,二者的联合拮抗作用不显著(P0.05),随Cu的增加,拮抗作用显著(P0.01)。     

Effect of AlCl3 concentration on nanoparticle removal by coagulation

In recent years, engineered nanoparticles, as a new group of contaminants emerging in natural water, have been given more attention. In order to understand the behavior of nanoparticles in the conventional water treatment process, three kinds of nanoparticle suspensions, namely multi-walled carbon nanotube-humic acid (MWCNT-HA), multi-walled carbon nanotube-N,N-dimethylformamide (MWCNT-DMF) and nanoTiO₂-humic acid (TiO₂-HA) were employed to investigate their coagulation removal efficiencies with varying aluminum chloride (AlCl₃) concentrations. Results showed that nanoparticle removal rate curves had a reverse “U” shape with increasing concentration of aluminum ion (Al^3 +). More than 90% of nanoparticles could be effectively removed by an appropriate Al^3 + concentration. At higher Al^3 + concentration, nanoparticles would be restabilized. The hydrodynamic particle size of nanoparticles was found to be the crucial factor influencing the effective concentration range (ECR) of Al^3 + for nanoparticle removal. The ECR of Al^3 + followed the order MWCNT-DMF > MWCNT-HA > TiO₂-HA, which is the reverse of the nanoparticle size trend. At a given concentration, smaller nanoparticles carry more surface charges, and thus consume more coagulants for neutralization. Therefore, over-saturation occurred at relatively higher Al^3 + concentration and a wider ECR was obtained. The ECR became broader with increasing pH because of the smaller hydrodynamic particle size of nanoparticles at higher pH values. A high ionic strength of NaCl can also widen the ECR due to its strong potential to compress the electric double layer. It was concluded that it is important to adjust the dose of Al^3 + in the ECR for nanoparticle removal in water treatment.