Phototransformation and ecotoxicity of the drug Naproxen-Na

The phototransformation of naproxen Na in aqueous medium has been investigated. Irradiation of the drug in drinking water affords seven photoproducts. Three of them are dimeric photoproducts isolated for the first time. The compounds, isolated by chromatographic processes, have been identified by spectroscopic means. The toxicity of the photoproducts and the parent drug has been assayed on Daphnia magna and Vibrio fischeri. The results indicate that some photoproducts are more toxic than naproxen.     

Photodegradation of pesticides .1. Photolysis rates and half‐life of acylanilides and their major metabolites in water

The photolysis in water solution of three fungicides (Metalaxyl, Benalaxyl, and Furalaxyl) was studied under artificial light. At λ = 254 Benalaxyl and Furalaxyl underwent fast degradation with rearrangement reactions less complex than those of Metalaxyl. Under A = 254–290 the photolysis was very fast and Benalaxyl and Furalaxyl show a common behaviour. This was found to be a kinetic consecutive process leading, at first, to N‐2,6‐xylyl‐D,L‐alaninate (II), which was degraded to 2,6‐dimethylaniline (IV). This amine gives unknown products. Metalaxyl underwent a parallel/consecutive photodegradtion to give (II) and N‐(methoxyacetyl)‐2,6‐dimethylaniline (VI). While (II) was easily converted to (IV) as earlier, (VI) was more stable to photolysis. Under λ > 290 all the fungicides shown very slow degradation with pseudo first order rate constants. The photoproducts were degraded faster than the parent compounds by factors from 13 to 1800. The presence of photosensitizer in water (humic acids or acetone) resulted in total decomposition of fungicides and of their photoproducts.     

Photodegradation of the organophosphorus pesticides chlorpyrifos,fenamiphos and vamidothion in water

The photodegradation of the pesticides chlorpyrifos, fenamiphos and vamidothion in water containing 2–4% methanol was examined. Acetone (5%) was added as photosensitizer in the photolysis of vamidothion. A suntest apparatus equipped with a xenon arc lamp which exhibits a radiation very close to natural sunlight was employed. Analyses were performed by direct injection of the water samples containing the photoproducts into a liquid chromatograph with diode array and thermospray mass spectrometric detection. The major photodegradation products were identified by matching their diode‐array spectra with the corresponding spectra of the authentic standards, their retention times and the spectra obtained using positive and/or negative thermospray mass spectrometry. 3,5,6‐trichloro‐2‐pyridinol, fenamiphos sulfoxide and vamidothion sulfoxide were the major photodegradation products from chlorpyrifos, fenamiphos and vamidothion, respectively.     

Use of mercury in agriculture and its relationship to environmental pollution

Linuron samples at 75mg/L concentration were photolyzed with ultraviolet lamps or with natural sunlight. Ten photoproducts were identified and yields were determined for the more significant photoproducts resulting from either sunlight or ultraviolet lamp photolysis.     

Photolysis of 3‐(3,4‐dichlorophenyl)‐1, 1 ‐Dimethylurea (Diuron) in dilute aqueous solution

Diuron samples at 40mg/L concentration were photolyzed with ultraviolet lamps and with natural sunlight to determine if data from ultraviolet lamp photolysis could be used to predict results from sunlight photolysis. Seven photoproducts were identified from the photolysis experiments. The identified photoproducts and the photoproduct yields were essentially the same for the two light sources.     

Photolysis of chlorimuron‐ethyl

To examine the photostability of the herbicide chlorimuron‐ethyl (ethyl‐2‐[[[[(4‐methoxy‐6‐chloro‐pyrimidin‐2‐yl)amino]carbonyl]amino]sulfonyl]benzoate) in the field, model experiment with organic solvent was performed. Photolysis of chlorimuron‐ethyl in methanol solution resulted in the formation of seven major and five minor photoproducts, isolated and identified by spectroscopic methods. Major photoproducts reported were formed by the cleavage of sulfonylurea bridge, contraction of sulfonylurea bridge, methylation of urea nitrogen and cyclisation, whereas minor products by dechlorination.     

Photochemistry of halogenated benzene derivatives. part xii.∗ effects of sodium nitrite on the environmental phototransformation of bromoxynil (3,5‐dibromo‐4‐hydroxybenzonitrile) herbicide in water: The photoincorporation of nitrite ions into bromoxynil

Photoreactions of the herbicide bromoxynil (3,5‐dibromo‐4‐hydroxybenzonitrile) (1) were extensively studied in water containing various concentrations of sodium nitrite with radiation of wavelengths around 313 nm. In the absence of NaNO₂, the quantum yields for the photodecomposition of the herbicide I amounted to 0.054±0.005, while such data was in the range of 0.047 ±0.005 to 0.023 ±0.003 in the presence of 0.5 to 25.0 × 10^‐3 m of the inorganic salt. These quantum yield data for the phototransformation of 1 without and with the presence of sodium nitrite followed the Stern‐Volmer equation. The rates of the photolytic destruction of bromoxynil (1) in water were slower in the presence than in the absence of NaNO₂. For example, the irradiation of the 7.8 x 10^‐6M aqueous solution of 1 in the presence of 10 mM sodium nitrite gave rise to the production of three main photoproducts, viz., 3‐bromo‐4‐hydroxy‐5‐nitrobenzonitrile (2), 4‐hydroxy‐3‐nitrobenzonitrile (3), and an “unidentified photoproduct”; 4. In the case of this photoreaction of compound 1, the percentages of maximum concentration of the photoproducts 2, 3, and 4 were achieved after 14, 44.5, and 60‐min photolyses of 1, respectively; the starting material 1 completely disappeared after 60‐min photolysis. The photoproducts 2 and 3 were identified through the interpretation of the GC‐MS data. Both thhe mass and FT‐IR spectra of the product 4 indicated the possible presence of a COOH group in 4.     

灭幼脲(Ⅲ)在水相中光解产物的鉴定

采用HPLC—UV及GC—MS技术鉴定了灭幼脲(Ⅲ)在水相中的表观光解产物,通过分析表观光解反应与暗反应产物的相对含量,确认对氯苯基异氰酸酯和邻氯苯甲酰胺是灭幼脲(Ⅲ)在永相中光解的主要产物。另外,依据反应产物的组成和相对含量,对灭幼脲(Ⅲ)在水相中的光解反应速率常数作了估算。     

Photodegradation of the organophosphorus insecticide ‘Phorate’

The photolysis of Phorate(I) (0,0‐diethyl S‐ethyl thiomethyl phosphordithioate) has been studied as a thin film on a glass surface and in a solution of methanol‐water (60:40) by ultraviolet light (λ > 290 nm). The rate of disappearance of Phorate in the solution show first order Kinetics with a rate constant of 4.9 × 10^–5 S ^–1. The half‐life of (I) exposed on a glass surface is found to be 5 hours. The structure of the major photoproducts were characterised by ¹H NMR and mass spectroscopy.     

Effect of natural aquatic humic substances on the photodegradation of bisphenol A

The photochemical degradation of bisphenol A (BPA) was studied in the presence of natural humic substances from different origins under simulated solar irradiation. BPA underwent insignificant direct photolysis in neutral water, but rapid photosensitized degradation in four humic substances solutions via pseudo-first-order reaction occurred. The photo-degradation rate of BPA was insensitive to the different initial BPA concentrations and was inhibited in aerated solution compared with the deoxygenated medium. The reactive oxygen species (ROS) such as ·OH and ¹O₂ produced from excitation of humic substances under irradiation was determined from the quenching kinetic experiment using molecular probe. The five main intermediate photoproducts of BPA in Nordic lake fulvic acid (NOFA) were tentatively identified using gas chromatography/mass spectrometer (GC/MS). Based on the identification of ROS and the analysis of photoproduct formation, the possible phototransformation pathways of BPA were proposed, involving the direct photolysis due to the energy transfer from the triplet state humic substance (³HS*) to BPA molecules and hydroxyl radical addition and oxidation as well.     

Photodegradation of the organophosphorus herbicide “anilophos”

Photodecomposition of the organophosphorus herbicide anilophos [S‐(N‐(4‐chlorophenyl) N‐isopropyl carbaniloyl methyl] 0,0‐dimethyl phosphorodithioate has been studied in methanol. It underwent oxidation, hydrolysis and dimerisation on irradiation with U.V. light and produced a number of photoproducts which were characterised by ¹H‐NMR and Mass spectroscopy.     

Photochemical reactions of musk ketone

The photolysis of musk ketone in cyclohexane and methanol afforded several cyclization products while the product spectrum in cyclohexene and squalene was characterized by an amino derivative and a ring expansion product, respectively. On cellulose stearate layers the photochemical reactions of musk ketone proceeded readily both under sun simulator and in natural sunlight and several photoproducts identified in solvent experiments were detected. Photoproducts were isolated by preparative HPLC and TLC and analyzed by means of HPLC, GC/MS, MS, LC/MS, ¹H‐ and ¹³C‐NMR.     

Light induced transformation of isoprothiolane on glass,soil, and plant surface

Photolysis of isoprothiolane (di-isopropyl 1,3-dithiolan-2-ylidenemalonate) was studied as a thin film on glass surface, soil surface, and plant surface. Three photoproducts, namely 1,3-dithiolan-2-ylidenepropane, 1,3-dithiolan-2-ylidenemalonic acid, and 1,3-dithiolan-2-ylidenemethane have been identified on the basis of GC-MS method. The major route of photodegradation of this compound is through the de-esterification process, followed by de-carboxylation and rearrangement. The rate of photodegradation in all cases followed first-order kinetics with a statistically significant correlation coefficient.     

Synthesis of substituted diphenylamines and carbazoles: phototransformation products of diclofenac

The formation of stable and potentially hazardous compounds as a result of photochemical transformation of pharmaceutical substances in the aquatic environment implies a demand for standard compounds within environmental analysis. The major phototransformation products of diclofenac are comprised of substituted diphenylamines and carbazoles. Substituted diphenylamines were synthesized by Ullmann condensation reactions between anilines and halobenzenes. Monochlorocarbazoles were obtained from palladium-catalyzed intramolecular coupling reactions of monochlorinated diphenylamines, photocyclization of dichlorinated diphenylamines or by direct chlorination of carbazole. The availability of synthetic photoproducts of diclofenac is of critical importance for further studies on the environmental fate as well as the ecotoxicological effects of the drug in the environment.     

Kinetic studies of imazapyr photolysis and characterization of the main photoproducts

The fate of imazapyr (2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid), a broad-spectrum herbicide in the imidazolinone family, has been studied upon UV irradiation. Most of the photoproducts occurring during the photodegradation have been characterized by means of liquid chromatography and mass spectrometry coupled techniques (LC-MS). The use of high resolution mass spectrometry has allowed to maximize the chemical information obtained from a single LC-MS analysis. The degradation of a 10?ppm imazapyr solution leads to pyridine derivatives which remain in solution during 50–100?h while the imazapyr is completely degraded after 6?h.     

Photodegradation of atrazine and ametryn with visible light using water soluble porphyrins as sensitizers

The photodegradation of the herbicides atrazine and ametryn with visible light in aerated neutral aqueous solutions and 5, 10, 15, 20-tetrakis (2,6-dichloro-3-sulfophenyl) porphyrin or 5, 10, 15, 20-tetrakis (4-sulfophenyl) porphyrin as sensitizers are reported for the first time. Our findings show that the degradation percentage reached 30% for atrazine and 63% for ametryn. The final photoproducts were characterized as dealkylated s-triazines. Photolysis of the pesticides in the presence of a singlet oxygen quencher showed only a minor contribution of this type of mechanism, while a bimolecular quenching reaction between the triplet state of the sensitizer and the pesticides is excluded by flash photolysis studies. It is proposed that the mechanism may involve the formation of a superoxide radical anion from the triplet state of the sensitizer and molecular oxygen, followed by a radical decomposition pathway. Selected article from 1st International Meeting on Photochemistry, Photocatalysis and Environmental Applications, Agadir, 2006, organised by Prof. Dr. Ait Ichou, University Ibn Zohr, Agadir, Morocco     

北京和上海市居民冬夏两季饮用水消费习惯

饮用水是人体暴露于有毒物质的重要暴露源,为了定量描述饮用水中污染物对暴露人群所造成的危害,世界各国的科学家们对饮用水的健康风险评价做了大量的研究.通常,健康风险评价需要污染物毒理学数据和暴露人群的暴露剂量数据.目前,针对很多的有毒污染物,国际上已经建立了应用于健康风险评价的毒理学数据库,同时积累了大量可用的有效数据.而对于暴露人群的暴露剂量数据,则是健康风险评价所要研究的重点.正确估计暴露人群的暴露剂量需要消费者提供大量的消费信息.例如,暴露人群每天消费的饮用水水量.美国环保局(EPA)认为成人每天消耗的饮用水水量为2L·d-1,此外,饮用水的消耗量会随着暴露人群的身体活动状况和所处环境状况(温度,湿度等)的改变而改变.目前,许多研究都是关于饮用水消费信息的,总体来讲这些研究结果基本上与美国环保局所采用的饮水消耗数据相一致.需要说明的是中国居民有完全不同于西方人的饮用水消费方式,如果在进行中国居民饮用水健康风险评价过程中应用美国环保局的假设会带来较大的不确定性.饮用水健康风险评价工作在我国开展并不多,尤其缺少中国居民饮用水消费习惯的数据库.这些客观条件使得在我国进行饮用水健康风险评价时只能从基础做起,积累有效的数据.本研究以北京和上海两座城市居民为研究对象,2002年到2004年分冬夏两季分别进行了4次饮用水消费习惯调查.研究采用随机入户方式(2004年至2005年),与中央电视台-索福瑞联合调查有限公司合作进行.参加调查的家庭从中央电视台入户收视率调查的基础数据库中随机抽取,在抽取过程中兼顾了不同城区、年龄结构、知识结构、收入水平等因素.研究表明,北京和上海居民冬夏两季的日均饮水量分别为2.2L·d-1、1.7L·d-1、2.0L·d-1和1.8L·d-1,这一结果和美国环保局的假设基本一致.同时本研究考察了性别、年龄、职业和季节对应用水消费习惯的影响.研究表明,日均饮水量随年龄的增加有增加的趋势,这一趋势在北京的夏季调查中趋势明显(p=0.01);男性的日均饮用水量大于女性,在上海冬季和夏季调查中均存在显著的差异(冬季:p=0.01;夏季:p=0.04);季节也同样影响被访者的日均饮水量,但是在4次调查中均未发现显著性差异.在北京冬季和夏季的调查中均发现了工作地点对饮用水消费习惯的显著影响(夏季p=0.01和冬季p=0.00).研究同样考察了居民饮用水消费类型,调查结果表明,煮沸后的自来水是中国居民最主要的日常饮品(上海夏季:58.3%;上海冬季67.9%;北京夏季:42.7%;北京冬季:60.0%).同时消费桶装纯净水的被访者也占有相当的比重(上海夏季:36.2%;上海冬季:24.7%;北京夏季:30.7%;北京冬季:60.0%).研究同时表明,在中国居民的日常生活中牛奶和豆奶已经成为重要的日常饮品.极少量的居民(北京夏季:10.7%;北京冬季5.7%;上海夏季1.2%;上海冬季0.6%)有直接饮用自来水的习惯.研究表明滞留水(在自来水水管中滞留6h以上的自来水)是对人体健康影响最大的水,而在我们的调查中,中国居民几乎不直接饮用滞留水.当前,饮用水健康风险评价在世界范围内蓬勃展开,但是这一技术在我国还处于起步阶段.本研究作为饮用水健康风险评价的前期工作,为其在中国的进一步发展提供了基础性的数据.     

Calculation of the minimum ecological water requirement of an urban river system and its deployment: A case study in Beijing central region

The minimum ecological water requirements of an urban river system and water deployment are key elements in integrated water resources planning and urban ecological construction. Based on a review of ecological water requirement calculation methods and considering the different ecological functions of an urban river system, the ecological function method was used in this paper to calculate the components of the ecological water requirements of an urban river. An envelope curve-based method was proposed for assessing the minimum ecological water requirements of an urban river system. Water resources deployment strategies designed to meet the minimum ecological water requirements were described. Then, the minimum ecological water requirements of the urban river system in Beijing central region, selected as a case study, were investigated. The key parameters for assessing the minimum ecological water requirement in the Beijing urban river system were determined. Based on the ecological objectives and the current status of the different urban river systems within the Beijing central region, the minimum ecological water requirements were calculated. Different types of water sources, including rainwater, upstream water, and reclaimed water, were deployed to meet the ecological water requirements for the urban river system in the Beijing central region.     

Water Consumption Habit in General Population of Shanghai and Beijing, China

饮用水是人体暴露于有毒物质的重要暴露源,为了定量描述饮用水中污染物对暴露人群所造成的危害,世界各国的科学家们对饮用水的健康风险评价做了大量的研究. 通常,健康风险评价需要污染物毒理学数据和暴露人群的暴露剂量数据. 目前,针对很多的有毒污染物,国际上已经建立了应用于健康风险评价的毒理学数据库,同时积累了大量可用的有效数据. 而对于暴露人群的暴露剂量数据,则是健康风险评价所要研究的重点. 正确估计暴露人群的暴露剂量需要消费者提供大量的消费信息. 例如,暴露人群每天消费的饮用水水量. 美国环保局(EPA)认为成人每天消耗的饮用水水量为2L·d-1,此外,饮用水的消耗量会随着暴露人群的身体活动状况和所处环境状况(温度,湿度等)的改变而改变. 目前,许多研究都是关于饮用水消费信息的,总体来讲这些研究结果基本上与美国环保局所采用的饮水消耗数据相一致. 需要说明的是中国居民有完全不同于西方人的饮用水消费方式,如果在进行中国居民饮用水健康风险评价过程中应用美国环保局的假设会带来较大的不确定性. 饮用水健康风险评价工作在我国开展并不多,尤其缺少中国居民饮用水消费习惯的数据库. 这些客观条件使得在我国进行饮用水健康风险评价时只能从基础做起,积累有效的数据. 本研究以北京和上海两座城市居民为研究对象,2002年到2004年分冬夏两季分别进行了4次饮用水消费习惯调查. 研究采用随机入户方式(2004年至2005年),与中央电视台-索福瑞联合调查有限公司合作进行. 参加调查的家庭从中央电视台入户收视率调查的基础数据库中随机抽取,在抽取过程中兼顾了不同城区、年龄结构、知识结构、收入水平等因素. 研究表明,北京和上海居民冬夏两季的日均饮水量分别为2.2L·d-1、1.7L·d-1、2.0L·d-1和1.8L·d-1,这一结果和美国环保局的假设基本一致. 同时本研究考察了性别、年龄、职业和季节对应用水消费习惯的影响. 研究表明,日均饮水量随年龄的增加有增加的趋势,这一趋势在北京的夏季调查中趋势明显(p=0.01);男性的日均饮用水量大于女性,在上海冬季和夏季调查中均存在显著的差异(冬季：p=0.01;夏季：p=0.04);季节也同样影响被访者的日均饮水量,但是在4次调查中均未发现显著性差异. 在北京冬季和夏季的调查中均发现了工作地点对饮用水消费习惯的显著影响(夏季p=0.01 和冬季p=0.00). 研究同样考察了居民饮用水消费类型,调查结果表明,煮沸后的自来水是中国居民最主要的日常饮品(上海夏季：58.3%;上海冬季67.9%;北京夏季：42.7%;北京冬季：60.0%). 同时消费桶装纯净水的被访者也占有相当的比重(上海夏季：36.2%;上海冬季：24.7%;北京夏季：30.7%;北京冬季：60.0%). 研究同时表明,在中国居民的日常生活中牛奶和豆奶已经成为重要的日常饮品. 极少量的居民(北京夏季：10.7%;北京冬季5.7%;上海夏季1.2%;上海冬季0.6%)有直接饮用自来水的习惯. 研究表明滞留水(在自来水水管中滞留6h以上的自来水)是对人体健康影响最大的水,而在我们的调查中,中国居民几乎不直接饮用滞留水. 当前,饮用水健康风险评价在世界范围内蓬勃展开,但是这一技术在我国还处于起步阶段. 本研究作为饮用水健康风险评价的前期工作,为其在中国的进一步发展提供了基础性的数据.     

Methods to alleviate the inhibition of sludge anaerobic digestion by emerging contaminants: a review

The rising occurrence of emerging contaminants in sludges both inhibits the anaerobic digestion of sludges and induces health issues when sludges are recycled in agriculture, calling for methods to remove contaminants. Here we review emerging pollutants in wastewater treatment plants, before and after anaerobic digestion. We present their inhibitory effects and remediation methods to alleviate inhibition. Pharmaceuticals have been detected in about 50% of the sludge samples. Sewage sludge contaminants include 19% of diuretics, 16–21% of lipid-modifying agents, hydrochlorothiazide, diclofenac, furosemide, clarithromycin, atorvastatin, and carbamazepine. Levels of antibiotics, azithromycin, ciprofloxacin, and estrone range from 500 to 600 ng/g in sludges from wastewater treatment plants. Remediation methods comprise electrooxidation, ultrasonication, thermal hydrolysis, ozonation, and bioaugmentation. Fermenting the sludges with acidogenic bacteria reduces the level of emerging pollutants in the supernatant. Nonetheless, liquid digestates still contains emerging pollutants such as sunscreen octocrylene at 147 ug/L and acetaminophen at 58.6 ug/L. As a result, pretreatment of sludge containing emerging pollutants is required.