Characterization of spatial and temporal patterns in surface water quality: a case study of four major Lebanese rivers.

In this work, four major Lebanese rivers were investigated, the Damour, Ibrahim, Kadisha, and Orontes, which are located in South, Central, and North Lebanon and Bekaa Valley, respectively. Five sampling sites were considered from upstream to downstream, and 12 sampling campaigns over four seasons were conducted during 2010-2011. Thirty-seven physicochemical parameters and five microbial tests were evaluated.

Oxidation of 2-aminophenol to 2-amino-3H-phenoxazin-3-one with monochloramine in aqueous environment: A new method for APO synthesis?

Reaction of 2-aminophenol (2AP) with monochloramine in aqueous solution was investigated at pH 8.5 and 25 °C, with an excess of monochloramine. 2-Amino-3H-phenoxazin-3-one (APO) was the major product formed in about 70% yield.

Reliable quantification of bisphenol A and its chlorinated derivatives in human breast milk using UPLC-MS/MS method.

Bisphenol A is a widespread industrial chemical which over the past decade has demonstrated its toxicity as an endocrine disruptor. Chlorine present in drinking water may react with bisphenol A to form chlorinated derivatives, which have demonstrated a heightened level of estrogenic activity. In this work, we have comprehensively validated a method using on-line SPE-UPLC-MS/MS and isotope dilution quantification to measure bisphenol A and its chlorinated derivatives in human breast milk according to accepted guidelines.

Quantification of bisphenol A, 353-nonylphenol and their chlorinated derivatives in drinking water treatment plants.

Bisphenol A (BPA) and nonylphenols (NP) are of major concern to public health due to their high potential for human exposure and to their demonstrated toxicity (endocrine disruptor effect). A limited number of studies have shown that BPA and NP are present in drinking water. The chlorinated derivatives that may be formed during the chlorination step in drinking water treatment plants (DWTP) exhibit a higher level of estrogenic activity than their parent compounds.

Selenium exposure in subjects living in areas with high selenium concentrated drinking water: results of a French integrated exposure assessment survey.

Background: Selenium is an essential element which can be toxic if ingested in excessive quantities. The main human exposure is food. In addition, intake may be boosted by consumption drinking water containing unusual high selenium concentration.

Cellular response of the amoeba Acanthamoeba castellanii to chlorine, chlorine dioxide, and monochloramine treatments.

Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae.

Liquid chromatography coupled with tandem mass spectrometry method for thirty-three pesticides in natural water and comparison of performance between classical solid phase extraction and passive sampling approaches.

The aim of this study is to propose an analytical method for determining different classes of pesticides in water using LC-ESI-MS/MS. Two techniques of field-sampling and analyte extraction were used: solid phase extraction (SPE) of water samples from active sampling and field exposure of Polar Organic Chemical Integrative Samplers (POCIS). We have worked with thirty-three molecules representing eight pesticide classes: carbamates, chloroacetanilides, dicarboximides, morpholines, organophosphorous, phenylureas, strobilurines and triazines.

Effect of the adsorbate (Bromacil) equilibrium concentration in water on its adsorption on powdered activated carbon. Part 3: Competition with natural organic matter.

This study (part 3) was carried out to investigate the effect of the natural organic matter (NOM) concentration on Bromacil (pesticide) adsorption on powdered activated carbon (PAC) in the same experimental conditions as in our previous studies (parts 1 and 2). Our previous findings showed that Bromacil adsorption in buffered pure water (pH 7.8) occurred at two types of site.

Acanthamoeba castellanii: cellular changes induced by chlorination.

Chlorination is a well-known disinfection method, used in water treatment to inactivate various microorganisms, it induces numerous cellular changes. Even though Acanthamoebae are frequently found in water, the cellular changes induced in Acanthamoebae have not been described in the literature. Acanthamoebae are pathogenic amoebae and may provide a reservoir for pathogenic bacteria such as Legionellapneumophila; it is consequently important to understand the response of this amoeba to chlorination, and our study was indeed aimed at examining cellular changes in Acanthamoebae following chlorination.

Effect of the adsorbate (Bromacil) equilibrium concentration in water on its adsorption on powdered activated carbon. Part 2: Kinetic parameters.

The application of several monosolute equilibrium models has previously shown that Bromacil adsorption on SA-UF (Norit) powdered activated carbon (PAC) is probably effective on two types of sites. High reactivity sites were found to be 10-20 less present in a carbon surface than lower reactivity sites, according to the q(m) values calculated by isotherm models. The aims of this work were trying, primarily, to identify the kinetic-determinant stage of the sorption of Bromacil at a wide range of initial pesticide concentrations (approximately 5 to approximately 500 microg L(-1) at pH 7.

Effect of the adsorbate (Bromacil) equilibrium concentration in water on its adsorption on powdered activated carbon. Part 1. Equilibrium parameters.

This study was carried out to investigate the adsorption equilibrium and kinetics of a pesticide of the uracil group on powdered activated carbon (PAC). The experiments were conducted at a wide range of initial pesticide concentrations (approximately 5 microg L(-1) to approximately 500 microg L(-1) at pH 7.8), corresponding to equilibrium concentrations of less than 0.

Oxidation of bisphenol A by ozone in aqueous solution.

Based on the literature data, an efficient removal of bisphenol A (BPA) during ozonation can be expected under water treatment conditions. However, up to now, the degradation products have not been identified. This has been the main point of this study.

Kinetic and mechanistic investigations of progesterone reaction with ozone.

The removal of progesterone by ozone in aqueous solution was studied in this work. The absolute rate constant was evaluated and first by-products were identified. The reaction was studied in the 2.

Kinetics of aqueous ozone-induced oxidation of some endocrine disruptors.

This study investigated aqueous ozone-induced oxidation of six endocrine disruptors (EDs: 4-n-nonylphenol, bisphenol A, 17alpha-ethinylestradiol, 17beta-estradiol, estrone, and estriol). In the first part, ED ozonation kinetics were studied over a pH range of 2.5-10.

Aqueous chlorination kinetics of some endocrine disruptors.

The aqueous chlorination kinetics of six endocrine disruptors (EDs: 4-n-nonylphenol, beta-estradiol, estrone, estriol, 17alpha-ethinylestradiol, progesterone) were studied in the 3.50-12.00 pH range, at 20+/-2 degrees C, in the presence of an excess of total chlorine.

Effects of chloride and sulfate on the rate of oxidation of ferrous ion by H2O2.

The rates of oxidation of Fe(II) by H(2)O(2) in the presence of sodium perchlorate, sodium nitrate, sodium chloride and sodium sulfate salts (0-1M) have been compared in the study. Experiments were carried out in a batch reactor, in the dark, at pH <3, 25+/-0.5 degrees C and at controlled ionic strength (< or =1M).

Phototransformation of selected organophosphorus pesticides in dilute aqueous solutions.

The photochemical transformation of four selected organophosphorus pesticides (OPs) has been studied in water. Because of their extensive use, disulfoton, isofenfos, isazofos and profenofos were chosen for this study. A solid phase extraction method has been developed to allow low-concentration experiments.

Modeling of bromate formation by ozonation of surface waters in drinking water treatment.

The main objective of this paper is to try to develop statistically and chemically rational models for bromate formation by ozonation of clarified surface waters. The results presented here show that bromate formation by ozonation of natural waters in drinking water treatment is directly proportional to the "Ct" value ("Ctau" in this study). Moreover, this proportionality strongly depends on many parameters: increasing of pH, temperature and bromide level leading to an increase of bromate formation; ammonia and dissolved organic carbon concentrations causing a reverse effect.

A comparative study of the effects of chloride, sulfate and nitrate ions on the rates of decomposition of H2O2 and organic compounds by Fe(II)/H2O2 and Fe(III)/H2O2.

The effects of chloride, nitrate, perchlorate and sulfate ions on the rates of the decomposition of hydrogen peroxide and the oxidation of organic compounds by the Fenton's process have been investigated. Experiments were conducted in a batch reactor, in the dark at pH < or = 3.0 and at 25 degrees C.

Charge transfer of iron(III) monomeric and oligomeric aqua hydroxo complexes: semiempirical investigation into photoactivity.

Aqueous hydrolyses of iron(III) solutions were studied using electronic spectroscopy. Complete spectra from 200 to 800 nm were obtained for the four ferric aqua hydroxo complexes: Fe(H(2)O)(6)(3+), Fe(OH)(H(2)O)(5)(2+), Fe(OH)(2)(H(2)O)(4)(+), and the dimer Fe(2)(mu-Omicron Eta)(2)(H(2)O)(8)(4+). Semiempirical Zindo/s calculations were employed to assign which types of electronic transfers are involved so that the photoactivity as regards the photoreduction dissociation Fe(III)(aq) Fe(II)(aq) + OH* can be discussed.