Development of methods for establishing nutrient criteria in lakes and reservoirs: A review

Nutrient criteria provide a scientific foundation for the comprehensive evaluation, prevention,control and management of water eutrophication. In this review, the literature was examined to systematically evaluate the benefits, drawbacks, and applications of statistical analysis,paleolimnological reconstruction, stressor-response model, and model inference approaches for nutrient criteria determination. The developments and challenges in the determination of nutrient criteria in lakes and reservoirs are presented. Reference lakes can reflect the original states of lakes, but reference sites are often unavailable. Using the paleolimnological reconstruction method, it is often difficult to reconstruct the historical nutrient conditions of shallow lakes in which the sediments are easily disturbed. The model inference approach requires sufficient data to identify the appropriate equations and characterize a waterbody or group of waterbodies, thereby increasing the difficulty of establishing nutrient criteria. The stressor-response model is a potential development direction for nutrient criteria determination, and the mechanisms of stressor-response models should be studied further. Based on studies of the relationships among water ecological criteria, eutrophication, nutrient criteria and plankton, methods for determining nutrient criteria should be closely integrated with water management requirements.     

Occupational exposure assessment of phthalate esters in indoor and outdoor microenvironments

Phthalate esters(PAEs) are widely used as plasticizers in consumer products. PAEs are a group of environmental hormone which disrupts human and animals' endocrine systems. Different occupational groups are exposed to various levels of PAEs. In the present study, four typical occupational groups were chosen, including doctors, college teachers, college students, and drivers who worked in public traffic system. In order to understand the exposure levels to PAEs via inhalation, air samples were collected from multiple microenvironments including indoor and outdoor in Hangzhou to measure the gas and particle concentrations of six PAEs, together with time spent in different microenvironments of these four groups. A comprehensive PAEs exposure model was built to estimate the daily PAEs exposure through inhalation, oral and dermal pathways. The Monte Carlo simulation results show that doctors were exposed to the highest level of PAEs, and consequently had the highest health risk among these four occupational groups. In contrast, college students had the lowest health risk. By setting the exposure level of staying in residences as the baseline, doctors and drivers were two occupations exposed to high PAEs health risk. Di-(2-ethylhexyl) phthalate(DEHP) was the largest contributor among the six phthalates, posing moderate health risk(10-5–10-6) to every occupation. For traffic microenvironments alone, the total exposure levels for different transportation modes were in the descending order of busses, cars, cabs, tubes, motor bikes, and walking.     

危化品海水快速分离工艺探究

目前国内外均无成熟的危化品海水分离装置,急需探索出可以有效进行危化品海水原位快速分离的工艺,解决海上危化品泄漏后危化品污染海水原位分离困难的问题,提高海上应急水平。用二甲苯作为海上运输常见危化品的代表,选择几种典型的污染物水分离工艺(重力分离、膜分离、吸附分离),分别在海水条件下进行了效果测试,并对3种工艺进行了串联组合和效果验证。结果表明:重力分离能够在10 min内将二甲苯海水高比例混合物快速分离,并将二甲苯质量浓度降至160～200 mg/L;膜分离能够耐冲击地完成对大质量浓度(如20 000 mg/L)二甲苯海水混合物的分离,将二甲苯质量浓度降至60 mg/L左右,但处理后的污染海水再过膜没有进一步的分离效果;吸附分离根据前期的柱试验结果选择了吸附容量较大且适宜填罐的活性炭种类IPG1240;重力分离-膜分离-吸附分离的组合能够实现危化品与海水的快速分离。     

Algal uptake of dissolved organic nitrogen in wastewater treatment plants

The algal uptake of dissolved organic nitrogen(DON) in the anaerobic–anoxic–oxic(A_2O)process was investigated in this study. Anaerobic, aerobic and effluent DON samples from two wastewater treatment plants(WWTPs) were separated into hydrophilic and hydrophobic fractions using a DAX-8 resin coupled with an anion exchange resin and a nanofiltration(NF)pretreatment. Hydrophilic DON accounted for 66.66%–88.74% of the entire DON for the two plants evaluated. After a 15-day incubation, 16.95%–91.75% DON was bioavailable for algal growth, and untreated samples exhibited higher DON bioavailability, with 52.83% DON average uptake rates, compared with the hydrophilic and hydrophobic fractions(45.53% and 44.40%, respectively) because the pretreatment caused the inorganic salt to be resistant to algae. Anaerobic untreated samples, hydrophilic fractions and hydrophobic fractions showed higher DON reduction rates and higher biomass accumulation compared with the other DON fractions due to the decomposition of resistant organics by anaerobic and anoxic bacteria.DON in aerobic and effluent samples of plant A was more bioavailable than that of plant B with usages of 27.49%–55.26% DON. DON bioavailability in the anaerobic–anoxic–oxic process decreased in the following order: anaerobic effluent aerobic. The DON contents were reduced after anaerobic treatment in the two plants. The EEM-PARAFAC model identified three DON components, including two humic acid-like substances and one protein-like substance in plant A and two protein-like substances and one humic acid-like substance in plant B.     

2,6-二甲基-β-环糊精螯合强化葎草对Pb吸收的影响和机理

采用盆栽试验研究了EDTA、2,6-二甲基-β-环糊精对Pb污染土壤上葎草生长及Pb积累特性的影响.土壤中硝酸铅含量分别为0、600和1200 mg·kg~(-1),螯合剂的含量为硝酸铅含量的0.5倍和1.0倍.结果表明:EDTA和2,6-二甲基-β-环糊精对Pb离子均有显著増溶作用,且二者之间没有差异;EDTA对葎草的生长有轻微抑制作用,而2,6-二甲基-β-环糊精与对照没有差异,原因可能是形成了Pb-2,6-二甲基-β-环糊精络合物降低了Pb的毒性;EDTA和2,6-二甲基-β-环糊精都显著促进了葎草根、茎、叶部对Pb离子的吸收.EDTA处理的葎草在硝酸铅含量为600mg·kg~(-1),螯合剂浓度为0.9 mmol·L~(-1)时,转移率达到最大值1.34,而2,6-二甲基-β-环糊精的转移率最大值为0.36.虽然2,6-二甲基-β-环糊精的转移率较低,但由于葎草的生物量大,2,6-二甲基-β-环糊精可以作为葎草提取修复的一种新型螯合剂,葎草也可用作植物提取修复的参考植物.由于2,6-二甲基-β-环糊精具有独特的“内疏水,外亲水”结构,推测其促进葎草吸收转移Pb的机理可能是会以Pb-2,6-二甲基-β-环糊精络合物的溶解物形式在葎草的质外体通道中移动,进入木质部,最终通过蒸腾流的驱动转运至地上部.     

浅述职业紧张对员工健康的影响及干预策略

随着医学模式从生物医学模式向生物—心理—社会医学模式的转变,心理社会因素对健康的影响日益加重。文章探讨职业紧张与健康的关系及其可能会给作业员工健康造成的损害和相关干预措施。得出:职业紧张对健康的影响是较长时间内过大的压力所表现出来的累积性反应,其发展过程是缓慢和渐进的,可能会出现高血压、冠心病、中风、睡眠障碍等症状,在日常工作中,有必要采取有针对性的干预措施,其最基本的办法是干预生产活动中的紧张因素,提高作业员工的控制和适应能力,最终达到良性循环。     

外生菌根真菌Xerocomus chrysenteron产漆酶能力及其对外加DDT和重金属的响应

为评价外生菌根真菌红绒盖牛肝菌(Xerocomus chrysenteron)在不同营养条件和污染条件下产漆酶的能力,采用改良的Kottke营养液培养法研究了不同碳氮比、DDT处理和重金属处理对X.chrysenteron漆酶活性的影响,探讨了不同处理对漆酶活性的影响机制。结果表明:(1)X.chrysenteron漆酶粗酶对底物ABTS的米氏常数Km值为0.038 mmol·L-1。在接种X.chrysenteron后,漆酶活性的峰值出现在菌丝生长的稳定期,静置培养63 d后漆酶活性可达118 U·L-1。在静置和振荡条件下,X.chrysenteron在改良的Kottke营养液中的最大产漆酶量均为157 U·L-1,振荡培养不能提高最大漆酶产量。高的碳氮比条件下(葡萄糖与(NH4)2HPO4质量浓度之比为20)可以获得较大的漆酶活性。(2)在培养的第54天,1 mg·L-1 DDT和5 mg·L-1DDT处理的培养基中的漆酶活性相比对照分别提高了0.5倍和1倍,显示出DDT对产漆酶的诱导作用。(3)低浓度(1 mmol·L-1)的不同重金属对X.chrysenteron漆酶活性有不同的影响,在培养的第54天,Cu和Cd能够将漆酶活性分别提高2.6倍和0.3倍,Mn对漆酶活性没有明显的影响,Zn降低了漆酶活性,Hg则完全抑制了漆酶活性。高浓度的Cu(5 mmol·L-1)对漆酶活性的提高不明显,而高浓度的Cd(5 mmol·L-1)则降低了漆酶活性。重金属对X.chrysenteron漆酶活性的影响机制可能包括通过对漆酶基因的诱导或抑制,以及对菌丝生物量的影响,进而对漆酶活性产生影响。研究表明,高的碳氮比、适当质量浓度的DDT处理及低浓度的Cu、Cd处理均能促进X.chrysenteron产漆酶,显示出其在POPs和重金属复合污染环境下对POPs的降解潜力。     

不同粒径矿化垃圾对大麦生长发育和斑马鱼胚胎毒性效应研究

将太原东山新沟垃圾填埋场矿化垃圾筛分为900~300μm、300~150μm、150~105μm、105~90μm和90~0μm共5个不同粒径范围,制备浸出液。在分析不同粒径矿化垃圾浸出液的理化指标基础上,研究了矿化垃圾浸出液对大麦和斑马鱼胚胎生长发育的影响。结果显示,矿化垃圾浸出液p H值随粒径的减小而减小,电导率、CODCr、全盐量和总氮则随粒径的减小而增大。矿化垃圾浸出液对大麦的萌发、根长和芽长均表现出抑制作用,且抑制作用随粒径的减小而显著增加,90~0μm抑制作用最强,具体表现为染毒1 d、2 d和3 d后,大麦种子处理组萌发率为对照组的39.74%、56.38%和59.81%;染毒3 d、5 d和7 d后,根长分别为对照组的57.08%、48.33%和41.66%;芽长分别为对照组的66.60%、64.79%和61.65%。斑马鱼胚胎暴露于不同粒径的矿化垃圾浸出液中,胚胎生长发育的毒害作用与粒径大小呈现明显负相关关系,即在最小粒径90~0μm处理后,卵凝结、血循环异常、孵化率、心包水肿及脊柱畸形影响作用达到最大,这5个指标值分别为40.28%、50.00%、51.39%、31.94%和29.17%。以上研究表明,矿化垃圾浸出液对大麦和斑马鱼胚胎生长发育的毒性效应与矿化垃圾粒径分布显著相关,小粒径矿化垃圾(90~0μm)的生态毒性效应最大。     

Kinetics of Solvent Blue and Reactive Yellow removal using microwave radiation in combination with nanoscale zero-valent iron

We investigated the efficiency and kinetics of the degradation of soluble dyes over the p H range 5.0–9.0 using a method employing microwave radiation in combination with nanoscale zero-valent iron(MW–n ZVI). The n ZVI particles(40–70 nm in diameter) were prepared by a liquid-phase chemical reduction method employing starch as a dispersant.Compared to the removal of Solvent Blue 36 and Reactive Yellow K-RN using only n ZVI,more rapid and efficient dye removal and total organic carbon removal were achieved using MW–n ZVI. The dye removal efficiency increased significantly with decreasing p H, but was negligibly affected by variation in the microwave power. The kinetics of dye removal by MW–n ZVI followed both an empirical equation and the pseudo first-order model, while the kinetics of dye removal using n ZVI could only be described by an empirical equation. It was also concluded that microwave heating of the dye solutions as well as acceleration of corrosion of n ZVI and consumption of Fe(II) were possible reasons behind the enhanced dye degradation.     

城市生活垃圾焚烧持久性有机污染物(POPs)研究进展

综述了城市生活垃圾焚烧过程中涉及的持久性有机污染物的种类、单体分布特征、质量平衡特征、相互转化关系及I-TEQ指示化合物相关研究进展,以期为国内垃圾焚烧厂的污染控制提供新的思路。