The development of a chemical 'fingerprint' to characterise dissolved organic matter in natural waters

A suite of twelve assays has been used to 'fingerprint' dissolved organic matter (DOM). The assays were applied directly to filtered natural water samples. Temperature, pH and conductivity accounted for the environmental conditions on-site. Bulk carbon characteristics were assayed by measuring UV absorbance at 200 and 240 nm, colour in grade Hazen, DOC (dissolved organic carbon), fluorescence (excitation 370 nm, emission 450 nm) and the complexation of phenol itself. Measuring hydroxybenzenes ('monophenolics'), polyhydroxybenzenes ('polyphenolics') and total phenolics with the Gibbs, Prussian Blue and Folin-Ciocalteau assays, respectively, determined the phenolics pool. The methodology was tested on six freshwater sites in North Wales chosen to provide differences in vegetation, land-use and water chemistry and sampled once during each season. A novel approach for the presentation of the data has been developed that combines all range normalised assay results for each site and each season within one polar plot, hence the term 'fingerprint'. The data was also analysed using principal component factor analysis. Assays characterised as determining the chemical properties of DOM contributed to Factor 1 and explained 59% of the variation in the data. Assays apparently determined by the water matrix, contributed to Factor 2 and explained 20% of the variation within the data. The factor scores obtained for each site showed more variation for assays relating to the chemical properties of DOM than to the surrounding water matrix. The methodology was found to detect chemical changes within DOM for each site throughout the year and different responses for different sites.     

Multidimensional fluorescence studies of the phenolic content of dissolved organic carbon in humic substances

Indicators suggest that the amount of dissolved organic carbon (DOC) in natural waters may be increasing. Climate change has been proposed as a potential contributor to the trend, and under such a mechanism, the phenolic content of DOC may also be increasing. This study explores the assessment of the phenolic character of DOC using multidimensional fluorescence spectroscopy as a more convenient alternative to traditional wet chemistry methods. Parallel factor analysis (PARAFAC) is applied to fluorescence excitation emission matrices (EEMs) of humic samples to analyze inherent phenolic content. The PARAFAC results are correlated with phenol concentrations derived from the Folin-Ciocalteau reagent-based method. The reagent-based method reveals that the phenolic content of five International Humic Substance Society (IHSS) samples varies from approximately 5.2 to 22 ppm Tannic Acid Equivalents (TAE). A four-component PARAFAC fit is applied to the EEMs of the IHSS sample dataset and it is determined by PARAFAC score correlations with phenol concentrations from the reagent-based method that components C2, C3, and C4 have the highest probability of containing phenolic groups. The results show the potential for PARAFAC analysis of multidimensional fluorescence data for monitoring the phenolic content of DOC.     

Adsorption and detection of some phenolic compounds by rice husk ash of Kenyan origin

Rice husk ash (RHA) obtained from a rice mill in Kenya has been used as an inexpensive and effective adsorbent (and reagent) for the removal (and detection) of some phenolic compounds in water. The abundantly available rice mill waste was used in dual laboratory-scale batch experiments to evaluate its potential in: (i) the removal of phenol, 1,3-dihydroxybenzene (resorcinol) and 2-chlorophenol from water; and (ii) the detection of 1,2-dihydroxybenzene (pyrocatechol) and 1,2,3-trihydroxybenzene (pyrogallol) present in an aqueous medium. The studies were conducted using synthetic water with different initial concentrations of the phenolic compounds. The effects of different operating conditions (such as contact time, concentration of the phenolic compounds, adsorbent quantity, temperature, and pH) were assessed by evaluating the phenolic compound removal efficiency as well as the extent of their color formation reactions (where applicable). RHA exhibits reasonable adsorption capacity for the phenolic compounds and follows both Langmuir and Freundlich isotherm models. Adsorption capacities of 1.53 x 10(-4), 8.07 x 10(-5), and 1.63 x 10(-6) mol g(-1) were determined for phenol, resorcinol and 2-chlorophenol, respectively. Nearly 100% adsorption of the phenolic compounds was possible and this depended on the weight of RHA employed. For the detection experiments, pyrocatechol and pyrogallol present in water formed coloured complexes with RHA, with the rate of colour formation increasing with temperature, weight of RHA, concentration of the phenolic compounds and sonication. This study has proven that RHA is a useful agricultural waste product for the removal and detection of some phenolic compounds.     

Results of a technology demonstration project to compare rapid aquatic toxicity screening tests in the analysis of industrial effluents

The results of a 'BioWise' demonstration project to assess the comparative sensitivity and practicality of seven new assays for the direct assessment of ecotoxicity in industrial effluents are presented. In addition the aim of the project was to validate the results of the new assays against benchmark data generated from non-proprietary, rapid, microplate screening assays using the regulatory species; freshwater crustacean Daphnia magna and green algae Selenastrum capricornutum, chosen in view of their environmental relevance. The new commercial test assays were: Daphnia magna, Selenastrum capricornutum and Thamnocephalus platyurus Toxkits supplied by Vickers Laboratories Ltd, containing dormant, immobilised life stages of the test species; GreenScreen EM, a yeast based assay for genotoxicity and general acute toxicity supplied by Gentronix Ltd; and CellSense a mediated, amperometric whole cell biosensor based on immobilised activated sludge and E. coli. 38 effluent samples supplied by members of SOCSA (Specialised Organic Chemicals Sector Association) were examined over a period of 13 months, in the project co-ordinated by the AstraZeneca Brixham Environmental Laboratory, and part funded by BioWise via the UK Government Department of Trade and Industry.     

水中多种酚类化合物衍生化方法研究

对水中14种酚类化合物的衍生化过程进行研究,选取不同衍生化试剂、衍生温度和衍生时间、最大衍生量等多个对衍生效率有决定性影响的参数进行优化。通过上述条件的优化选择,实现了对苯酚、氯代酚、甲基酚和硝基酚等14种不同类型酚类化合物最优的衍生化,衍生效率达到75．5％～119％。     

Validation of plant based bioassays for the toxicity testing of Indian waters

Plant-based bioassays have recently gained remarkable popularity among the toxicological/eco-toxicological assessment procedures. The reasons for their wide use are comparative simplicity, sensitivity, and cost-effectiveness as well as a good correlation with other toxicity tests. The present study describes the use of two plant bioassays, Allium cepa test and seed germination test in the evaluation of the toxicity/genotoxicity of industrial waste water and river water and standardization with the commonly occurring pollutants in Indian waters namely heavy metals and phenolics. Both tests were standardized to suit the Indian conditions, and the local varieties were used. Both bioassays responded significantly with the test range of heavy metals and phenolics. The toxicity of heavy metals was in the order of Cu > Ni > Cd in both the tests whereas 2,4-dinitrophenol was the most toxic among the phenolic compounds. Cabbage, millet, and cucumber, respectively, were found to be the most sensitive in the seed germination test for the test heavy metals and phenols. Significant amounts of chromosomal abnormalities including bridges, stickiness, and fragmentations were recorded with both the industrial waste water and the XAD concentrated river water samples by A. cepa test.     

Development of GP and GEP models to estimate an environmental issue induced by blasting operation

Air overpressure (AOp) is one of the most adverse effects induced by blasting in the surface mines and civil projects. So, proper evaluation and estimation of the AOp is important for minimizing the environmental problems resulting from blasting. The main aim of this study is to estimate AOp produced by blasting operation in Miduk copper mine, Iran, developing two artificial intelligence models, i.e., genetic programming (GP) and gene expression programming (GEP). Then, the accuracy of the GP and GEP models has been compared to multiple linear regression (MLR) and three empirical models. For this purpose, 92 blasting events were investigated, and subsequently, the AOp values were carefully measured. Moreover, in each operation, the values of maximum charge per delay and distance from blast points, as two effective parameters on the AOp, were measured. After predicting by the predictive models, their performance prediction was checked in terms of variance account for (VAF), coefficient of determination (CoD), and root mean square error (RMSE). Finally, it was found that the GEP with VAF of 94.12%, CoD of 0.941, and RMSE of 0.06 is a more precise model than other predictive models for the AOp prediction in the Miduk copper mine, and it can be introduced as a new powerful tool for estimating the AOp resulting from blasting.     

水中多种酚类化合物同步提取方法研究

对水中14种酚类化合物的液液萃取过程进行研究,选取不同萃取溶剂体系、水样pH和盐析条件等多个对萃取效率有决定性影响的参数进行优化。通过上述条件的优化选择,实现了同步对包括低沸点的苯酚、一氯代酚及较难提取的甲基酚和硝基酚等14种不同类型酚类化合物最优的萃取,提取效率达到75.2%~110.3%。     

Recovery of a freshwater wetland from chemical contamination after an oil spill

In March 2009, a cargo ship spilled 250 tons of heavy fuel oil off the Queensland coast of Australia. The pristine National Park Moreton Island, seven nautical miles to the east of the spill site, was most affected by the oil slick. Contamination of the island's shoreline was widespread, with freshwater wetlands particularly slow to recover as clean-up needed to be carefully managed to avoid damage to this sensitive ecosystem. During the clean-up process on Moreton Island a monitoring program was initiated using traditional chemical analysis in combination with bioanalytical techniques to assess the extent and variability in contamination at sites on the shoreline and freshwater wetlands. Water accommodated fractions (WAF) of oil residues from samples taken directly after the spill on the shoreline showed the same level of toxic potency as samples from the wetland while baseline-toxicity equivalent concentrations (baseline-TEQ) and 2,3,7,8-tetrachlorodibenzodioxin equivalent concentrations (TCDDEQ) were much lower in oil collected from the sandy beach. The umuC assay for genotoxicity and the E-SCREEN assay for estrogenic effects indicated the extracts were not genotoxic or estrogenic. PAH concentrations and toxicity in grab water samples were below detectable levels, however, extracts from time integrated silicone passive samplers deployed for several weeks at the contaminated sites gave measurable responses in the bioassays with TCDDEQ levels increased relative to the control site. The low levels of baseline-TEQ and TCDDEQ present after 8 months had further decreased 6 months later indicating satisfactory recovery of this pristine ecosystem after an oil spill.     

Evaluation of concentration efficiency of the Pseudomonas aeruginosa phage PP7 in various water matrixes by different methods

Enteric viruses monitoring in surface waters requires the concentration of viruses before detection assays. The aim of this study was to evaluate different methods in terms of recovery efficiencies of bacteriophage PP7 of Pseudomonas aeruginosa, measured by real-time PCR, using it as a viral control process in water analysis. Different nucleic acid extraction methods (silica–guanidinium thiocyanate, a commercial kit (Qiagen Viral RNA Kit) and phenol–chloroform with alcohol precipitation) exhibited very low recovery efficiencies (0.08–4.18 %), being the most efficient the commercial kit used for subsequent experiments. To evaluate the efficiency of three concentration methods, PBS (as model for clean water) and water samples from rivers were seeded to reach high (HC, 10⁶ pfu ml^?1) and low concentrations (LC, 10⁴ pfu ml^?1) of PP7. Tangential ultrafiltration proved to be more efficient (50.36?±?12.91, 17.21?±?9.22 and 12.58?±?2.35 % for HC in PBS and two river samples, respectively) than adsorption–elution with negatively charged membranes (1.00?±?1.34, 2.79?±?2.62 and 0.05?±?0.08 % for HC in PBS and two river samples, respectively) and polyethylene glycol precipitation (15.95?±?7.43, 4.01?±?1.12 and 3.91?±?0.54 %, for HC in PBS and two river samples, respectively), being 3.2–50.4 times more efficient than the others for PBS and 2.7–252 times for river samples. Efficiencies also depended on the initial virus concentration and aqueous matrixes composition. In consequence, the incorporation of an internal standard like PP7 along the process is useful as a control of the water concentration procedure, the nucleic acid extraction, the presence of inhibitors and the variability of the recovery among replicas, and for the calculation of the sample limit of detection. Thus, the use of a process control, as presented here, is crucial for the accurate quantification of viral contamination.     

Combining passive sampling and toxicity testing for evaluation of mixtures of polar organic chemicals in sewage treatment plant effluent

Effluent from sewage treatment plants has been associated with a range of pollutant effects. Depending on the influent composition and treatment processes the effluent may contain a myriad of different chemicals which makes monitoring very complex. In this study we aimed to monitor relatively polar organic pollutant mixtures using a combination of passive sampling techniques and a set of biochemistry based assays covering acute bacterial toxicity (Microtox), phytotoxicity (Max-I-PAM assay) and genotoxicity (umuC assay). The study showed that all of the assays were able to detect effects in the samples and allowed a comparison of the two plants as well as a comparison between the two sampling periods. Distinct improvements in water quality were observed in one of the plants as result of an upgrade to a UV disinfection system, which improved from 24x sample enrichment required to induce a 50% response in the Microtox assay to 84x, from 30x sample enrichment to induce a 50% reduction in photosynthetic yield to 125x, and the genotoxicity observed in the first sampling period was eliminated. Thus we propose that biochemical assay techniques in combination with time integrated passive sampling can substantially contribute to the monitoring of polar organic toxicants in STP effluents.     

Hydrocarbon Uptake by Roots of Vicia faba (Fabaceae)

Vicia faba was grown in crude oil polluted soil and its roots were extracted for the detection and estimation of hydrocarbons. Saturated and unsaturated Aliphatic Hydrocarbons (AHs) ranging from C₂₂ to C₃₆ were identified in AHs fraction. However, PAHs were not present in the same extract. This could be due to the fact that PAHs being toxic compounds are not accumulated in the plant root extracts of V. faba grown in crude oil polluted soil. Three phytoalexins were identified and estimated by mass spectrometric analysis in the root extracts of V. faba. These three compounds are 2-t-butyl-4-(dimethyl benzyl) phenol, 2, 4-bis (dimethyl benzyl) phenol and 2,4-bis (dimethyl benzyl)-6-butyl phenol. These phenolics in V. faba are being reported for the first time. These compounds are presumably elicited as a direct stress on crude oil hydrocarbons on the roots of this plant.     

百里酚对酸雨样品分析的影响

在东亚酸雨监测网湿沉降监测的技术指南中 ,百里酚 (thymol)作为杀菌剂被推荐用于预先加入采样容器以抑制微生物对有机酸的分解 ,解决没有冰箱或难以使用冰箱地区的酸雨样品保存问题。本文实验了它对酸雨样品分析的影响。由于百里酚与苯酚结构相似 ,造成靛酚法的铵离子分析中吸光度有所降低。此外 ,在每 10 0 ml样品中百里酚加入量大于 40 mg时 ,离子色谱的基线明显变差     

A Characterization of Selected Endocrine Disruptor Compounds in a Portuguese Wastewater Treatment Plant

Anthropogenic compounds that are able to disrupt the endocrine system of wildlife species are a major cause for concern and have led to a demand for new screening methods. The identification and quantification of endocrine disruptor compounds at wastewater treatment plant is of major interest to assess the endocrine activity of wastewater treatment plant discharges into the environment. This study consists of a preliminary survey of concentrations of previously selected endocrine disruptor compounds, undertaken to establish environmental concentrations and to support a biological program assay exposing freshwater fish to them. Selected endocrine disrupting chemicals (APEs, bisphenol A and 17 β-estradiol) were measured in samples from a wastewater treatment plant located in Lisbon (Portugal), using recent commercial enzyme-linked immunosorbent assay kits and also LC-MS/MS. The results show that the wastewater treatment plant treatment process is efficient on the removal of target endocrine disruptor compounds. However, environmentally significant concentrations are still present in the treated effluent. The results also show that enzyme-linked immunosorbent assay kit is suitable for routine analysis of the selected compounds. The results are also useful since the wastewater treatment plant is located in a Mediterranean region, which results in an effluent with its own characteristics.     

Ascorbic acid reduction of active chlorine prior to determining Ames mutagenicity of chlorinated natural organic matter (NOM)

Many potable water disinfection byproducts (DBPs) that result from the reaction of natural organic matter (NOM) with oxidizing chlorine are known or suspected to be carcinogenic and mutagenic. The Ames assay is routinely used to assess an overall level of mutagenicity for all compounds in samples from potable water supplies or laboratory studies of DBP formation. Reduction of oxidizing disinfectants is required since these compounds can kill the bacteria or react with the agar, producing chlorinated byproducts. When mutagens are collected by passing potable water through adsorbing resins, active chlorine compounds react with the resin, producing undesirable mutagenic artifacts. The bioanalytical and chemoanalytical needs of drinking water DBP studies required a suitable reductant. Many of the candidate compounds failed to meet those needs, including 2,4-hexadienoic (sorbic) acid, 2,4-pentanedione (acetylacetone), 2-butenoic (crotonic) acid, 2-butenedioic (maleic and fumaric) acids and buten-2-ol (crotyl alcohol). Candidates were rejected if they (1) reacted too slowly with active chlorine, (2) formed mutagenic byproducts, or (3) interfered in the quantitation of known chlorination DBPs. L-Ascorbic acid reacts rapidly and stoichiometrically with active chlorine and has limited interactions with halogenated DBPs. In this work, we found no interference from L-ascorbic acid or its oxidation product (dehydroascorbic acid) in mutagenicity assays of chlorinated NOM using Salmonella typhimurium TA100, with or without metabolic activation (S9). This was demonstrated for both aqueous solutions of chlorinated NOM and concentrates derived from the involatile, ether-extractable chlorinated byproducts of those solutions.     

The potential of different bio adsorbents for removing phenol from its aqueous solution

The use of natural resources for the removal of phenol and phenolic compounds is being looked upon by researchers in preference to other prevailing methods. In the present study, different biosorbents, brown algae (Padina pavonia), fresh water macrophyta (Ceratophyllum demersum), and black tea residue, were tested as adsorbent for the removal of phenol from aqueous solutions. The optimum conditions for maximum adsorption in terms of concentration of the adsorbate and pH were identified. The results show that the initial concentration increases as the removal of phenol increases in C. demersum; in the case of the other two adsorbents, the initial concentration increases as the removal of phenol decreases, especially for an initial concentration lower than 100 and 1,000 μg/L for P. pavonia and black tea residue, respectively. Maximum percentage removal of phenol by each adsorbent is 77, 50.8, and 29 % for C. demersum, P. pavonia, and black tea residue, respectively. Also, the biosorption capacity was strongly influenced by the pH of the aqueous solution with an observed maximum phenol removal at pH of around 6–10. The first biosorbent (black tea residue) displays the maximum adsorption capacity at a pH of 10 with a percentage sorption capacity of 84 %; P. pavonia revealed a greater adsorption percentage at pH?10, reaching 30 %, while for C. demersum, the removal of phenol increases with the increase in initial pH up to 6.0 and decreases drastically with further increase in initial pH. The Freundlich, Langmuir, and Brauner–Emmet–Teller adsorption models were applied to describe the equilibrium isotherms. The results reveal that the equilibrium data for all phenol adsorbents fitted the Freundlich model which seemed to be the best-fitting model for the experimental results with similar values of coefficient of determination.     

The occurrence of glyphosate, atrazine, and other pesticides in vernal pools and adjacent streams in Washington, DC, Maryland, Iowa, and Wyoming, 2005–2006

Vernal pools are sensitive environments that provide critical habitat for many species, including amphibians. These small water bodies are not always protected by pesticide label requirements for no-spray buffer zones, and the occurrence of pesticides in them is poorly documented. In this study, we investigated the occurrence of glyphosate, its primary degradation product aminomethylphosphonic acid, and additional pesticides in vernal pools and adjacent flowing waters. Most sampling sites were chosen to be in areas where glyphosate was being used either in production agriculture or for nonindigenous plant control. The four site locations were in otherwise protected areas (e.g., in a National Park). When possible, water samples were collected both before and after glyphosate application in 2005 and 2006. Twenty-eight pesticides or pesticide degradation products were detected in the study, and as many as 11 were identified in individual samples. Atrazine was detected most frequently and concentrations exceeded the freshwater aquatic life standard of 1.8 micrograms per liter (microg/l) in samples from Rands Ditch and Browns Ditch in DeSoto National Wildlife Refuge. Glyphosate was measured at the highest concentration (328 microg/l) in a sample from Riley Spring Pond in Rock Creek National Park. This concentration exceeded the freshwater aquatic life standard for glyphosate of 65 microg/l. Aminomethylphosphonic acid, triclopyr, and nicosulfuron also were detected at concentrations greater than 3.0 microg/l.     

紫外分光光度法测定水中挥发酚的研究

目前,测定水中挥发酚一般采用4-氨基安替比林直接比色法和萃取法.为了克服4-氨基安替比林比色法测定挥发酚时需蒸馏、试剂不稳定等缺点或不足,提高挥发酚的检测上限,本文提出用紫外光度法测定水中挥发酚.用浓磷酸固定水样,用三氯甲烷、乙醚萃取水样,使挥发酚转移到乙醚中,排除多种离子的干扰;加入无水硫酸钠脱水,用乙醚定容,269 nm处测定吸光度.此方法不仅使测定范围增大到0.409～120 mg/L,且简便、快速、准确.本方法与标准方法有很好的可比性,同时,有很好的重现性.     

PBDEs in marine and freshwater sediments from Belgium: levels, profiles and relations with biota

Sediments from the Belgian North Sea (BNS), the Western Scheldt Estuary (SE) and freshwater watercourses from the Scheldt basin were analysed for eight PBDE congeners, namely BDEs 28, 47, 99, 100, 153, 154, 183 and 209. Previously analysed biological samples from the same locations in the BNS and the SE have been shown to contain large amounts of PBDEs. Surprisingly, PBDE concentrations in the sediments were below the LOQ for samples from the BNS (except BDE 209), while in those from the SE the sum of PBDEs (not including BDE 209) were higher and ranged from 0.20 to 0.41 ng g(-1) dw. BDE 209 could be detected in 83% of the samples from the BNS and in all the samples from the SE. Concentrations up to 1200 ng g(-1) were hereby measured in the SE. Compared to the marine and estuarine locations, the sediments from the freshwater watercourses were relatively more polluted with the lower brominated PBDEs (<0.20-19 ng g(-1) dw). BDE 209 concentrations up to 320 ng g(-1) dw were measured in those sediments. However, the contribution of BDE 209 to the total amount of PBDEs varied much more at the freshwater locations than in the SE, which suggests a different input of pollutants. PBDE profiles observed in biological samples do not match the profiles of the sediments. BDE 183 and 209 could not be quantified in biota, although these congeners were undoubtedly present in the sediments. This raises questions about the bioavailability of these congeners in the environment.     

Thio arsenosugars in freshwater mussels from the Danube in Hungary

In contrast to the large body of data on naturally-occurring arsenic compounds in marine organisms, relatively little is known about arsenic speciation in freshwater biota. We report an investigation using HPLC-ICPMS into the arsenic compounds in five species of freshwater mussels collected from five sites from the Danube in Hungary. Total arsenic concentrations in the mussels ranged from 3.8-12.8 mg As kg(-1). The arsenic speciation patterns were broadly similar for mussels representing each of the five species and five sites, but quite different from those reported for marine mussels. The major extractable arsenicals were two oxo arsenosugars (glycerol sugar and phosphate sugar), and their thio analogues (thio glycerol sugar and thio phosphate sugar). Arsenobetaine, usually the major arsenical in marine organisms, was not a significant compound in the freshwater mussels and was detected in only three of the 11 samples. This is the first report of thio arsenosugars in freshwater biota and suggests that these compounds may be common and widespread naturally-occurring arsenicals.