A review of the significance and formation of chlorinated N-organic compounds in water supplies including preliminary studies on the chlorination of alanine,tryptophan, tyrosine,cytosine, and syringic acid

Nitrogenous organic compounds are of environmental significance because of their potential as both trihalomethane (THM) and nonpurgeable organic halide (NPOX) precursors. They additionally lead to falsely positive tests for free available chlorine (FAC) and are components in the reaction of chlorine to form dihaloacetonitriles (DHANs). A large number of naturally occurring nitrogenous compounds additionally react readily with aqueous chlorine exerting significant chlorine demand. Such reactions generally involve the substitution of chlorine for hydrogen on a nitrogen atom. Additionally, N-chloroorganic materials may be produced even when the precursor concentration is low owing to the rapid specific rate of formation. While previous attention has been largely focused on nonpolar chlorinated organic contaminants such as THMs, the wide distribution of N-organic compounds in water, as well as their general reactivity towards aqueous chlorine, warrant further attention and study to this group of materials. Preliminary studies on the chlorination of several N-organic compounds at a few chlorine-to-compound molar ratios at pH 7 and 4.7 over several reaction intervals are presented. NPOX formation was quite rapid and comprised the greatest proportion of the total organic halide formed for the conditions studied.     

Environmental significance of nitrogenous organic compounds in aquatic sources

The presence of nitrogenous organic compounds in raw water sources for municipal supplies is of environmental concern because many of them exert significant chlorine demand, while some produce complex stable mutagenic products upon chlorination or are precursors to haloform formation. Seven N-organic compounds have been identified in municipal water concentrates (adenine, 5-chlorouracil, cytosine, guanine, purine, thymine, and uracil) at concentrations ranging from 20 to 860 μg/L. Eight compounds (adenine, cytosine, purine, pyrrole, thymine, tryptophan, tyrosine, and uracil) have been found in filtrates from cultures of either Anabaena flos aquae or Oscillatoria tenuis. Calculated CHCl₃ levels which might have formed at pH 7 in the water supplies were well below the maximum contaminant level (MCL) of 0.1 mg/L proposed by the U.S. Environmental Protection Agency (USEPA) for total trihalogenated methanes. Calculated levels of CHCl₃ which might have been formed under more alkaline conditions, however, were more than 10% of the MCL and were therefore significant. Calculated levels of combined forms of chlorine yielding falsely positive tests for free chlorine in some samples were slightly less or exceeded the 0.5 mg/L free chlorine residual generally taken as an acceptable level of disinfection. The demonstration of a parallel increase in organic nitrogen content with population density in two laboratory grown blue-green algal cultures, and the finding of elevated organic nitrogen values in a water supply sample collected during the occurrence of a blue-green algal bloom, suggested that summer algal bloom occurrence can add considerably to the organic nitrogen content and the trihalomethane potential of water supplies.     

Determination of potentially bioaccumulating complex mixtures of organochlorine compounds in wastewater: a review

Organic chlorine compounds can be persistent environmental contaminants and may be accumulated through the food chain to the aquatic organisms, to fish and humans, depending basically on their hydrophobic properties. Consequently, there is an interest to measure these organic compounds from both the scientific and regulatory communities. The analytical essays have been improved for measuring specific organic chlorine compounds that present the most toxicological potential (polychlorinated biphenyls [PCBs], certain pesticides and dioxins), although they are tedious and time-consuming procedures. The existing tests to measure adsorbable organic halogens (AOX) or extractable organic halogens (EOX) do not distinguish the more hydrophobic organic chlorine matter. The intention of this paper is to make a review of the existing methods to measure the potentially bioaccumulating organochlorine compounds (OCs) from wastewater and propose a methodology to a standardisation procedure for complex mixtures of OCs in wastewater, such as pulp mill effluents. A new method has been proposed for determining the most hydrophobic part of the extractable organic halogens (EOX(fob)), the lowest reported value is 0.6 microg/l, expressed as chloride, and the relative standard deviation at 20 microg/l is 7% on laboratory samples and 30% on real effluents. This new procedure could be a valuable tool to complement environmental risk assessment studies of wastewater discharges.     

上海农业生产中的自身污染与对策

上海市郊农业生产中的自身污染，目前主要有农药、化肥、畜禽粪尿和农用塑料薄膜。７０年代以前，上海曾施用过有机汞、有机氯等农药，对环境的影响较大。８０年代以来，影响较大的农药主要是有机磷和菊酯类；化肥主要是氮肥施用过多，导致蔬菜硝酸盐含量过高；畜禽粪尿已成为郊区突出的新污染源，造成水体的严重污染；各类农用塑料薄膜也是必须重视的新潜在污染物。     

Avoidance and toxicity responses of fish to intermittent chlorination

The ability of fish to actively avoid concentrations of chlorine in a steep, horizontal, laboratory-controlled gradient was found to be species-specific and dependent upon the acclimation temperature, water quality conditions, and the type of chlorine residual tested. Comparison of behavioral avoidances with the results from bioassays using some form of intermittent chlorination, as reported in the literature, indicated that LC₅₀ concentrations (levels that cause the mortality of half the test individuals in a designated time period) usually exceeded avoidance threshold concentrations.This chlorine avoidance study, which was carried out in a field laboratory that utilized New River water for holding and testing procedures, was located at the Glen Lyn power plant in southwestern Virginia. Two basic types of avoidance trials were employed, TRC (total residual chlorine) and chloramine (CRC) exposures. The TRC trials contained variable amounts of free (FRC) and combined residual chlorine (CRC) depending upon water quality, while in chloramine trials, the TRC exposure was mainly comprised of monochloramine with little or no FRC. The first significant avoidance in TRC trials for several fish species tested, varied from 0.05 mg/1 for coho salmon (Oncorhynchus kisutch) to 0.40 for channel catfish (Ictalurus punctatus). Low levels of hypochlorous acid (HOCl), which are considered to be a potentially toxic constituent of FRC, appeared to consistently influence the avoidance response. Initial avoidance concentrations to HOCl ranged from 0.01–0.02 mg/1 for coho salmon to 0.04–0.12 mg/1 for channel catfish, depending upon acclimation temperatures tested. The pH in river water was more influential than temperature in controlling the amount of HOCl present within the FRC at each TRC exposure. Avoidance responses by fish to CRC concentrations were either equal to or greater than TRC exposures and were dependent upon the ammonia-N content. Chloramine and FRC (specifically the HOCl fraction) have been reported to have different mechanisms of toxicity, which offered possible explanations for the differences observed in avoidance behavior. Chlorine residuals discharged from the Glen Lyn power plant in previous years have exceeded the LC₅₀ values reported for many species, although no major fish kills from chlorine have been documented. Behavioral avoidance responses by fish to potentially lethal chlorinated discharges in aquatic receiving systems may be a major mechanism of these populations in adapting to or interacting within these industrially influenced environments.     

Current status of models in determining optimum chlorination practices

Interest in mathematical models for predicting the fate of chlorine in natural waters arose in the 1970's, and evolution of these models has proceeded rapidly. The crudest of the models incorporate empirical estimates of chemical reactions in a single term to predict generic chlorine products such as total residual chlorine or free residual chlorine. A second order of model complexity includes use of multifactor predictor variables to approximate losses of chlorine via chemical reaction, but predictions are still couched in terms of generic chlorine products. The most sophisticated of the current models are based on specific chemical reactions and predict the identity and quantity of some (but not all) of the products resulting from chlorination of natural waters. None of these models have been sufficiently verified, but each has some potential value for assessment of environmental effects of chlorinated discharges. Evaluation of the strengths and weaknesses of existing models is presented to stimulate further model development and to direct the focus of chemical studies toward collection of data most critical for derivation of input parameters.     

A novel abbreviation standard for organobromine,organochlorine and organophosphorus flame retardants and some characteristics of the chemicals

Ever since the interest in organic environmental contaminants first emerged 50 years ago, there has been a need to present discussion of such chemicals and their transformation products using simple abbreviations so as to avoid the repetitive use of long chemical names. As the number of chemicals of concern has increased, the number of abbreviations has also increased dramatically, sometimes resulting in the use of different abbreviations for the same chemical. In this article, we propose abbreviations for flame retardants (FRs) substituted with bromine or chlorine atoms or including a functional group containing phosphorus, i.e. BFRs, CFRs and PFRs, respectively. Due to the large number of halogenated and organophosphorus FRs, it has become increasingly important to develop a strategy for abbreviating the chemical names of FRs. In this paper, a two step procedure is proposed for deriving practical abbreviations (PRABs) for the chemicals discussed. In the first step, structural abbreviations (STABs) are developed using specific STAB criteria based on the FR structure. However, since several of the derived STABs are complicated and long, we propose instead the use of PRABs. These are, commonly, an extract of the most essential part of the STAB, while also considering abbreviations previously used in the literature. We indicate how these can be used to develop an abbreviation that can be generally accepted by scientists and other professionals involved in FR related work. Tables with PRABs and STABs for BFRs, CFRs and PFRs are presented, including CAS (Chemical Abstract Service) numbers, notes of abbreviations that have been used previously, CA (Chemical Abstract) name, common names and trade names, as well as some fundamental physico-chemical constants.     

Monitoring of firefighters exposure to smoke during fire experiments in Portugal

Forest fires represent a serious threat to public security in Europe due to the large burned area. Moreover, smoke pollution due to forest fire events is an important public health issue for the communities directly affected, and particularly for the personnel involved in firefighting operations. Aiming to contribute to the scientific knowledge concerning firefighters exposure to forest fires smoke, data of individual exposure to carbon monoxide, nitrogen dioxide, volatile organic compounds, and particulate matter were obtained during experimental field fires for a group of 10 firefighters equipped with portable “in continuum” measuring devices. Measured values are very high exceeding the Occupational Exposure Standard limits, in particular for peak limit thresholds. These are the first measurements and analysis of firefighter's individual exposure to toxic gases and particles in fire smoke experiments in Europe. However, they already indicate that urgent measures to avoid these levels of exposure are needed.     

Partitioning of polar and non-polar neutral organic chemicals into human and cow milk

The aim of this work was to develop a predictive model for milk/water partition coefficients of neutral organic compounds. Batch experiments were performed for 119 diverse organic chemicals in human milk and raw and processed cow milk at 37°C. No differences (<0.3 log units) in the partition coefficients of these types of milk were observed. The polyparameter linear free energy relationship model fit the calibration data well (SD=0.22 log units). An experimental validation data set including hormones and hormone active compounds was predicted satisfactorily by the model. An alternative modelling approach based on log K(ow) revealed a poorer performance. The model presented here provides a significant improvement in predicting enrichment of potentially hazardous chemicals in milk. In combination with physiologically based pharmacokinetic modelling this improvement in the estimation of milk/water partitioning coefficients may allow a better risk assessment for a wide range of neutral organic chemicals.     

Removal of trace organic contaminants from domestic wastewater: A meta-analysis comparison of sewage treatment technologies

Trace organic contaminants (TrOCs), such as endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs), represent global threats to aquatic animals and ecosystems. A major source of TrOCs in the aquatic environment is via the discharge of treated sewage, so there is an urgent need to evaluate the comparative efficiencies of the most widely used sewage treatment technologies as regards elimination of these compounds from wastewater. To address this need, 976 published articles were compiled focusing on estimates of removal (%) for 20 common environmental TrOCs, from five major sewage treatment technologies: conventional activated sludge (CAS), oxidation ditch (OD), membrane bioreactor (MBR), ponds and constructed wetlands (PCW), and trickling biological filters (TBF). A quantitative meta-analysis was performed to compare standardized relative removal efficiencies (SREs) of the compounds amongst these technologies, and where possible potential sources of heterogeneity were considered (e.g., flow rates and chemical sorption potential). The results indicate that the most widely used CAS treatment and the less common TBF provide comparatively poor overall removal of common organic micropollutants. Membrane bioreactors appear to be capable of achieving the greatest overall removal efficiencies, but the sustainability and economic viability of this option has been questioned. Treatment with OD systems may be more economical while still achieving comparatively high removal efficiencies, and the analysis revealed OD to be the best option for targeting highly potent estrogenic EDCs. This study offers a unique global assessment of TrOC removal via leading sewage treatment technologies, and is an important step in the identification of effective options for treating municipal sewage.     

Gas chromatographic/mass spectrometric analysis of partially dechlorinated 1,1-diphenyl ethane and ethylene

Gas chromatographic relative retention time data and 70 eV electron impact mass spectra of partially dechlorinated derivatives of 1,1-bis-p-chlorophenyl-2,2,2-trichloroethane (DDT), and the corresponding, 2,2-dichloroethylene (DDE) are presented.The mass spectra of all partially dechlorinated ethane intermediates are characterized by fragmentation across the aliphatic CC bond, whereas the mass spectra of the corresponding olefins are characterized principally by CCl bond rupture. The mass spectral data, coupled with the observed systematic decrease in relative retention time that is a function of aromatic chlorine substitution, provides an almost complete set of relative retention time data for the homologous series of compounds between both DDT and 1,1-diphenylethane and DDE and 1,1,-diphenylethylene.     

Bacteriological quality of fresh produce and link to water and sanitation service access from informal markets in Mzuzu,Malawi

In 2010, the global burden of foodborne diseases was 33 million Disability-adjusted life years, and 40 % of this burden was for children under 5 years old (Havelaar et al. 2015). Our study site was informal public markets within Mzuzu, Malawi, visited between September and December 2015, during the dry season. From these markets, fresh vegetables, leafy greens (n = 85), tomato (n = 85), and green pepper (n = 35) were analyzed for Escherichia coli. The prevalence of E. coli was highest on leafy greens; it was found in 74 (87 %) of the 85 samples. The prevalence of E. coli in green peppers was found in 2 (6 %) of the 35 samples. The prevalence of E. coli was lowest on tomatoes; it was found in only 1 (1 %) of the 85 samples. The lack of adequate water and sanitation infrastructure in market areas may be contributing to the bacteriological contamination of fresh produce. Providing venders with free access to market area toilets containing hand-washing facilities with soap and wash water with a chlorine solution may reduce bacterial contamination of fresh produce. Universal and sustainable access to water and sanitation services must include informal public market areas to reduce diarrheal diseases transmitted through food within Sub-Saharan Africa countries.     

Efficiency of the activated carbon filtration in the natural organic matter removal

The removal and transformation of natural organic matter were monitored in the different stages of the drinking water treatment train. Several methods to measure the quantity and quality of organic matter were used. The full-scale treatment sequence consisted of coagulation, flocculation, clarification by flotation, disinfection with chlorine dioxide, activated carbon filtration and post-chlorination. High-performance size-exclusion chromatography separation was used to determine the changes in the humic substances content during the purification process; in addition, a UV absorbance at wavelength 254 nm and total organic carbon amount were measured. A special aim was to study the performance and the capacity of the activated carbon filtration in the natural organic matter removal. Four of the activated carbon filters were monitored over the period of 1 year. Depending on the regeneration of the activated carbon filters, filtration was effective to a degree but did not significantly remove the smallest molar mass organic matter fraction. Activated carbon filtration was most effective in the removal of intermediate molar mass compounds (range 1,000-4,000 g/mol). Regeneration of the carbon improved the removal capacity considerably, but efficiency was returned to a normal level after few months.     

Toxicological effects of disinfections using sodium hypochlorite on aquatic organisms and its contribution to AOX formation in hospital wastewater

Sodium hypochlorite (NaOCl) is often used for disinfecting hospital wastewater in order to prevent the spread of pathogenic microorganisms, causal agents of nosocomial infectious diseases. Chlorine disinfectants in wastewater react with organic matters, giving rise to organic chlorine compounds such as AOX (halogenated organic compounds adsorbable on activated carbon), which are toxic for aquatic organisms and are persistent environmental contaminants. The aim of this study was to evaluate the toxicity on aquatic organisms of hospital wastewater from services using NaOCl in pre-chlorination. Wastewater samples from the infectious and tropical diseases department of a hospital of a large city in southeast of France were collected. Three samples per day were collected in the connecting well department at 9 a.m., 1 p.m. and 5 p.m. during 8 days from 13 March to 22 March 2001, and a mixture was made at 6 p.m. with the three samples in order to obtain a representative sample for the day. The toxicity test comprised the 24-h EC50 on Daphnia magna and a bioluminescence assay using Vibrio fischeri photobacteria. Fecal coliforms and physicochemical analyses such as total organic carbon (TOC), chloride, AOX, total suspended solids (TSS) and chemical oxygen demand (COD) were carried out. Wastewater samples highlighted considerable acute toxicity on D. magna and V. fischeri photobacteria. However, low most probable numbers (MPN), ranging from <3 to 2400 for 100 ml, were detected for fecal coliforms. Statistical analysis, with a confidence interval of 95%, gave a strong linear regression assessed with r=0.98 between AOX concentrations and EC50 (TU) on daphnia. The identification of an ideal concentration of NaOCl in disinfecting hospital wastewater, i.e. its non-observed effect concentration (NOEC) on algae and D. magna, seems to be a research issue that could facilitate the control of AOX toxicity effects on aquatic organisms. Therefore, it would be necessary to monitor the biocide properties of NaOCl on fecal coliforms at various doses and its toxicity effects on aquatic organisms.     

Characterization of hydrocarbon pollutant burdens in petrochemical and refinery process streams

This paper describes techniques which provide for both qualitative and quantitative identification of major components in a process stream. The techniques and instrumentation have been deliberately chosen so as to be within the technical and financial reach of all but the smallecompany laboratory. The sample preparation steps consist of an initial series of extractions which isolate compounds into organic acid, base, and neutral compounds and a totally water soluble phase. Each fraction is then concentrated and subjected to thin-layer chromatography, gas chromatography, infrared spectroscopy or ultraviolet spectroscopy as appropriate. Results are given for laboratory samples, one a mixture of aniline, phenol, benzoic acid, m-nitrobenzaldehyde, 1-butanol, 2-hexanone, nonane, and cyclohexane, and the other a mixture of benzene, ethylbenzene, and styrene. Also, a qualitative analysis of a petroleum refinery desalter water is presented.     

Polar organic pollutants in air: A review of collection and analysis

Pollutants which are capable of being extracted into nonpolar solvent such as hexane have received the greatest attention in environmental monitoring. However, the polar fraction, inherently more difficult to analyze, is currently undergoing closer scrutiny. Sampling methods specifically designed to entrap polar particles and vapors are compared. Ion-exchange and reversed-phase liquid chromatography columns are examples of such specific sampling techniques. Various extraction schemes are presented with their individual problems and capabilities. Although there are numerous papers on the analysis of polar organic pollutants, few report actual measurements of ambient air samples. Current reports on polar organic pollutants measured in air samples are summarized. Polar organics are generally divided into three categories: acidic, basic, and neutral. Analytical methods relating to the following categories of polar organic compounds are reviewed: (1) phenols, mono- and dicarboxylic acids, and sulfonic acids, (2) aliphatic and aromatic amines, and (3) alcohols, aldehydes and ketones, phthalate esters, isocyanates and N-nitrosamines. Derivatization techniques, such as ester formation, are compared to the analysis of the unsubstituted compound. The formation of such derivatives is often the best way to trace specific compounds at very low levels.     

Soil mutagenicity as a strategy to evaluate environmental and health risks in a contaminated area

Soil can be a storage place and source of pollutants for interfacial environments. This study looked at a site contaminated with wood preservatives as a source of mutagens, defined routes and extent of the dispersion of these contaminants by particle remobilization and atmospheric deposition, considering an evaluation of risk to human health by quantifying mutagenic risk. Soil sampling sites were chosen at gradually increasing distances (150, 500 and 1700 m) from SI (industrial area pool) and indoor dust (pool in an area at risk at 385 m and at 1700 m). Mutagenesis was evaluated in the Salmonella/microsome assay, TA98, TA97a and TA100 strains with and without S9 mix, YGs strains 1041, 1042 and 1024 for nitrocompounds. Acid extracts were analyzed to define the effects of metals and organics for polycyclic aromatic hydrocarbons (PAHs) and nitroderivates, besides concentrations of these compounds and pentachlorophenol (PCP). Risk to human health was obtained from the relation between the quantified potential of mutagenic risk and estimated soil ingestion for children according to USEPA. Metal concentrations showed a gradient of responses with As, Cr and Cu (total metal) or Cr and Cu (fraction available) higher for SI. However, mutagenic effects of the mixtures did not show this grading. Site SR1700, without a response, was characterized as a reference. In organic extracts, the mutagenesis responses showed the mobility of these compounds from the source. In the surrounding area, a smaller pattern similar to SI was observed at SR150, and at the other sites elevated values of direct mutagenesis at SR500 and diminished effects at SR1700. Tests with YG strains indicated that nitrated compounds have a significant effect on the direct mutagenesis found, except SR500. The investigation of indoor dust in the surrounding area enabled confirmation of the particle resuspension route and atmospheric deposition, showing responses in mutagenicity biomarkers, PAH concentrations and PCP dosage similar to SI. The range of values obtained, considering the soil masses needed to induce mutagenicity was 0.02 to 0.33 g, indicating a high risk associated with human populations exposed, since these values found surpass the standard estimate of 200 mg/day of rate of soil ingestion for children according to USEPA. The study showed that it is essential to evaluate the extent of contamination from the soil to delimit remedial measures and avoid damage to the ecological balance and to human health.     

Numerical modeling of tracer transport in a contact tank

Chlorine is extensively used to disinfect the drinking water supply. However, the inefficient use of chlorine as a disinfectant can result in the formation of chemical compounds which can have adverse health effects. Numerical models are increasingly being used in the design of efficient chlorine contact tanks. In this paper, details are given of the application of a two-dimensional semi-time-centred implicit QUICK scheme to model the transport of a tracer in a scaled physical model of a serpentine chlorine contact disinfection tank. The model is shown to give good agreement with laboratory measurements in the compartments of the tank where the flow is relatively uniform over the depth.     

南京某地农业土壤中有机污染分布状况研究

对某大型矿业企业周边农业土壤中两类POPs物质——15种多环芳烃和有机氯农药（DDTs和HCHs）的残留量进行了调查。结果表明,PAHs检出率为100%,总残留量范围为312.2~27 580.9 μg·kg-1,且以四环以上多环芳烃组分为主。不同样区土壤PAHs残留量受常年风向影响明显。农业土壤中有机氯农药六六六和滴滴涕均有检出,但残留水平不高,分别为3.60 μg·kg-1(0.81~9.43 μg·kg-1)和11.13 μg·kg-1(3.31~43.81 μg·kg-1)。土壤有机氯农药的残留以p,p′ DDE和p,p′ DDT为主。土壤中HCHs的各异构体组分含量特征为α>β>γ>δ。部分采样点土壤仍可能有新的有机氯污染物来源。