Ecotoxicity evaluation of selected sulfonamides

Sulfonamides (SAs) are a group of antibiotic drugs widely used in veterinary medicine. The contamination of the environment by these pharmaceuticals has raised concern in recent years. However, knowledge of their (eco)toxicity is still very basic and is restricted to just a few of these substances. Even though their toxicological analysis has been thoroughly performed and ecotoxicological data are available in the literature, a systematic analysis of their ecotoxicological potential has yet to be carried out. To fill this gap, 12 different SAs were chosen for detailed analysis with the focus on different bacteria as well as non-target organisms (algae and plants). A flexible (eco)toxicological test battery was used, including enzymes (acetylcholinesterase and glutathione reductase), luminescent marine bacteria (Vibrio fischeri), soil bacteria (Arthrobacter globiformis), limnic unicellular green algae (Scenedesmus vacuolatus) and duckweed (Lemna minor), in order to take into account both the aquatic and terrestrial compartments of the environment, as well as different trophic levels. It was found that SAs are not only toxic towards green algae (EC₅₀ = 1.54-32.25 mg L⁻¹) but have even stronger adverse effect on duckweed (EC₅₀ = 0.02-4.89 mg L⁻¹) than atrazine - herbicide (EC₅₀ = 2.59 mg L⁻¹).     

Bromination of selected pharmaceuticals in water matrices

The bromination of five selected pharmaceuticals (metoprolol, naproxen, amoxicillin, phenacetin, and hydrochlorothiazide) was studied with these compounds individually dissolved in ultra-pure water. The apparent rate constants for the bromination reaction were determined as a function of the pH, obtaining the sequence amoxicillin > naproxen ? hydrochlorothiazide ≈ phenacetin ≈ metoprolol. A kinetic mechanism specifying the dissociation reactions and the species formed for each compound according to its pK_a value and the pH allowed the intrinsic rate constants to be determined for each elementary reaction. There was fairly good agreement between the experimental and calculated values of the apparent rate constants, confirming the goodness of the proposed reaction mechanism.In a second stage, the bromination of the selected pharmaceuticals simultaneously dissolved in three water matrices (a groundwater, a surface water from a public reservoir, and a secondary effluent from a WWTP) was investigated. The pharmaceutical elimination trend agreed with the previously determined rate constants. The influence of the main operating conditions (pH, initial bromine dose, and characteristics of the water matrix) on the degradation of the pharmaceuticals was established. An elimination concentration profile for each pharmaceutical in the water matrices was proposed based on the use of the previously evaluated apparent rate constants, and the theoretical results agreed satisfactorily with experiment. Finally, chlorination experiments performed in the presence of bromide showed that low bromide concentrations slightly accelerate the oxidation of the selected pharmaceuticals during chlorine disinfection.     

Partitioning behaviour of perfluorinated alkyl contaminants between water, sediment and fish in the Orge River (nearby Paris, France)

This paper reports on the partitioning behaviour of 15 perfluorinated compounds (PFCs), including C₄-C₁₀ sulfonates and C₅-C₁₄ carboxylic acids, between water, sediment and fish (European chub, Leuciscus cephalus) in the Orge River (nearby Paris). Total PFC levels were 73.0 ± 3.0 ng L⁻¹ in water and 8.4 ± 0.5 ng g⁻¹ in sediment. They were in the range 43.1-4997.2 ng g⁻¹ in fish, in which PFC tissue distribution followed the order plasma > liver > gills > gonads > muscle. Sediment-water distribution coefficients (log K_d) and bioaccumulation factors (log BAF) were in the range 0.8-4.3 and 0.9-6.7, respectively. Both distribution coefficients positively correlated with perfluoroalkyl chain length. Field-based biota-sediment accumulation factors (BSAFs) are also reported, for the first time for PFCs other than perfluorooctane sulfonate. log BSAF ranged between −1.3 and 1.5 and was negatively correlated with the perfluoroalkyl chain length in the case of carboxylic acids.     

巢湖流域水质状况与环境目标可达性分析

对巢湖湖区、巢湖环湖河流水质现状及变化趋势进行了调查。结果表明。“九五”以来,巢湖湖区水体以劣Ⅴ类为主;2000年以来,巢湖主要环湖河流中,南淝河、十五里河、派河和双桥河入湖常年水质为劣Ⅴ类,其主要污染物为氨氮。巢湖流域水体污染特征为：城市河段污染较重。点源污染较为集中;面源和生活污染贡献较大;从1998年以来,TP与TN质量浓度值一直处于较高水平。巢湖流域水质环境目标可达性分析表明,巢湖湖区整体上尚不能达到规划的目标。到2005年东半湖能稳定达标。南淝河能否实现达标排放。取决于合肥市的污水处理率及处理效果。十五里河、派河、双桥河水质受点源控制,只要加强管理,可达规划的目标。     

福州市城区内河引闽冲污后水质变化趋势及防治对策

简述了福州市城区内河河网结构特点和河网水文特征,对1994年-2003年福州城区内河的水质变化趋势进行了分析和评价。结果表明,自1998年福州市全面开始内河引水冲污工程后,内河水质得到了改善,有机污染得到缓解,基本消除了水体的黑臭现象。指出了在内河整治中存在的一些问题。提出,应优化引水方案,最大限度发挥效益;明确河段的使用功能,发挥其潜能;开展生物防治,建立良性循环的水生生态系统,对内河实施综合管理。     

固相萃取-气相色谱法测定水样中马拉硫磷残留

采用C-18小柱萃取、毛细管柱分离、气相色谱氢火焰离子化检测器（FID）测定水样中的马拉硫磷,检测限为0．12μg／L。试验了样品流量和洗脱剂对回收率的影响,结果表明样品流量为6mL／min、二氯甲烷作洗脱剂时,回收率较好。测定蒸馏水、地下水和河水样品,相对标准偏差〈2．2％。加标回收率在79．0％-109％之间。     

水体重金属污染生物监测的研究进展

综述了重金属的毒性效应和水体重金属污染的现状,介绍了利用水生藻类、浮游动物群落和底栖动物监测水体重金属污染的研究进展及发展趋势。     

水质凯氏氮标准样品的研究

提出了水质凯氏氮标准样品的研究方法。在研究过程中，完成了样品的配制、均匀性、稳定性等工作。经过多家实验室协作定值，确定了样品的标准值及不确定度，并提供使用。     

Detection of DDT and its metabolites in two estuaries of South China using a SPME-based device: First report of p,p′-DDMU in water column

A solid-phase microextration-based sampling method was employed to determine the concentrations of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (DDE) and 1-chloro-2,2-bis(p-chlorophenyl)ethene (DDMU), in two estuarine bays, Daya Bay and Hailing Bay, of South China. Six DDT components including p,p′-DDT, o,p′-DDD, p,p′-DDD, o,p′-DDE, p,p′-DDE, and p,p′-DDMU were detected in Hailing Bay, while only p,p′-DDD was found in Daya Bay. p,p′-DDD was the most abundant DDT component in both bays, sharply different from the previous finding in the water column of the Palos Verdes Shelf, California, USA that p,p′-DDE was prevalent. In addition, the occurrence of p,p′-DDMU (with a range of 0.047-0.21 ng/L in Hailing Bay) has not been reported around the globe, and its presence in our study region appeared to stem from dehydrochlorination of p,p′-DDD, favored under aerobic conditions, but further investigations are clearly needed to confirm the mechanism for generation of DDMU in estuarine environments.     

Management-oriented sensitivity analysis for pesticide transport in watershed-scale water quality modeling using SWAT

The Soil and Water Assessment Tool (SWAT) was calibrated for hydrology conditions in an agricultural watershed of Orestimba Creek, California, and applied to simulate fate and transport of two organophosphate pesticides chlorpyrifos and diazinon. The model showed capability in evaluating pesticide fate and transport processes in agricultural fields and instream network. Management-oriented sensitivity analysis was conducted by applied stochastic SWAT simulations for pesticide distribution. Results of sensitivity analysis identified the governing processes in pesticide outputs as surface runoff, soil erosion, and sedimentation in the study area. By incorporating sensitive parameters in pesticide transport simulation, effects of structural best management practices (BMPs) in improving surface water quality were demonstrated by SWAT modeling. This study also recommends conservation practices designed to reduce field yield and in-stream transport capacity of sediment, such as filter strip, grassed waterway, crop residue management, and tailwater pond to be implemented in the Orestimba Creek watershed.