Total suspended matter observation in the Pearl River estuary from in situ and MERIS data

Based on the cruise data collected in the Pearl River estuary (PRE) in May 2008, an empirical two-band model by using the ratio of R _rs at 629 and 671 nm was established to retrieve total suspended matter (TSM) concentration with the determination coefficient (R²) of 0.854, mean relative error (MRE) of 7.483%, and root-mean-square error (RMSE) of 1.295 mg L^???1. To match with medium resolution imaging spectrometer (MERIS) bands, in situ remote sensing reflectance was re-sampled to the bandwidth of 10 nm. The relationship between TSM and re-sampled R _rs at 620 nm (MERIS band 6) and 665 nm (MERIS band 7) are obtained (R² = 0.748, RMSE = 1.697 mg L^???1, MRE = 8.785%, n = 13). Additionally, to map the spatial distribution of TSM in the PRE, MERIS level_1B data were calibrated using a multiple linear regression model based on in situ R _rs. Another dataset collected in the PRE in January 2004 was used to validate the two-band model and also applied to map TSM distribution from MERIS image. The comparison between measured TSM values and modeled ones showed satisfactory results (R² = 0.753, MRE = 22.199%, and RMSE = 2.603 mg L^???1).     

Distribution, sources, and potential risk of polycyclic aromatic hydrocarbons (PAHs) in drinking water resources from Henan Province in middle of China

Distribution and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in drinking water resources have been carried out for the first time in Henan Province, China. Water samples collected from four river systems and their tributaries, as well as groundwater resources, were analyzed according to EPA method 525.2. Total of 68 water samples were collected in 18 cities in Henan province in May, August and November, 2001. Concentrations of sum of 16 priority PAHs in water samples ranged from 15 to 844 ng/L with a mean value of 178 +/- 210 ng/L (n = 68). The spatial and temporal distribution of PAHs showed that the Huanghe and the Huaihe river systems had relatively higher concentrations of total PAHs. Higher concentrations of total PAHs were observed in August and November than in May, with respective mean values of 262, 232 and 33.6 ng/L. Ratios of Ant/(Ant + Phe) and Flur/(Flur + Pyr) were calculated to evaluate the possible sources of PAH contamination, which indicated that the coal combustion sources were the main contributors to PAHs in most drinking water resources. Some petrogenic (or pyrolytic) sources of PAHs were also found. The toxic equivalency factors (TEFs) were used to calculate benzo[a]pyrene equivalents (BaPE) for water samples. The average value of BaPE was 0.6 ng/L. The values in most stations were much lower than the guideline values in drinking water of Chinese Environmental Protection Agency (CEPA, 2.8 ng/L) and the US Environmental Protection Agency (US EPA, 200 ng/L). Overall, the drinking water resources in Henan province showed some carcinogenic potential.     

Residues of organochlorine pesticides in water and suspended particulate matter from the Yangtze River catchment of Wuhan, China

The residues of 13 organochlorine pesticides (OCPs) in surface water and HCHs and DDTs in suspended particulate matter (SPM) from rivers and lakes in Yangtze River catchment of Wuhan, China, were investigated. The concentration of total OCPs in surface water varied from 1.01 to 46.49 ng l⁻¹ (mean 10.55 ng l⁻¹). The levels of total HCHs (ΣHCH) and total DDTs (ΣDDT) in surface water were in the range of 0.55–28.07 ng l⁻¹ and lower than detection limit to 16.71 ng l⁻¹, respectively, which was lower than Chinese standards on the whole. For OCPs residues in SPM, the mean levels varying from 0.20 to 34.72 ng l⁻¹ and 0.46 to 2.72 ng l⁻¹ for ΣHCH and ΣDDT, respectively, which ranked the relatively higher levels among Chinese studied rivers. Results from this investigation showed that previous excessive usage of technical OCPs was the main reason for the residues of HCHs and DDTs both in surface water and SPM, although some new sources were likely to occurred in the region. Apart from the OCPs in SPM originated from upstream in flood season, one of the important sources of OCP residues both in water and SPM in Yangtze River was supposed to be the inputs of its tributaries. Additionally, in situ water-SPM phase distributions of OCPs indicated that HCHs tended totransport with water as well as DDTs was prone to combine with SPM in Yangtze River catchment of Wuhan.     

Survey of the occurrence of residues of methyl tertiary butyl ether (MTBE) in Dutch drinking water sources and drinking water

An indicative survey has been carried out in The Netherlands investigating the presence of methyl tertiary butyl ether (MTBE) in drinking water and the corresponding sources. In total, 71 different sites used for the preparation of drinking water in The Netherlands were sampled in two successive seasons in 2001 involving the analysis of 156 samples. (ground water (n = 88), surface water (n = 17), bank filtrate water (n = 6) and drinking water (n = 45)). To combine high sample throughput with high selectivity and sensitivity, off-line purge and trap for sampling and gas chromatography mass spectrometry equipped with an automated thermal desorption sampler (TDS-GC-MS) was selected as the preferred analytical methodology. The developed procedure enabled the analysis of at least 40 samples per day and provided a limit of quantification of 2 ng l(-1). In the first period 63 samples of raw water were analyzed. Concentrations ranged between < 10 ng l(-1) and 420 ng l(-1) with a median concentration below 10 ng l(-1). The second period was focused at the re-sampling of positive locations (MTBE > 10 ng l(-1)) and a few additional drinking water utilities of which both the raw and drinking water of the utilities were analyzed. The median concentration of MTBE in the selected set of drinking water samples was 20 ng l(-1) (n = 45). At one location MTBE was found at a level of 2900 ng l(-1) caused by point source contamination of the ground water (11 900 ng l(-1)). Special attention has been paid to the quality of the results by analyzing all samples in duplicate and the analysis of control samples during each series of analyses.     

Monitoring of nitrates in drinking water from agricultural and residential areas of Podravina and Prigorje (Croatia)

Nitrates are the most common chemical pollutant of groundwater in agricultural and suburban areas. Croatia must comply with the Nitrate Directive (91/676/EEC) whose aim is to reduce water pollution by nitrates originating from agriculture and to prevent further pollution. Podravina and Prigorje are the areas with a relatively high degree of agricultural activity. Therefore, the aim of this study was, by monitoring nitrates, to determine the distribution of nitrates in two different areas, Podravina and Prigorje (Croatia), to determine sources of contamination as well as annual and seasonal trends. The nitrate concentrations were measured in 30 wells (N?=?382 samples) in Prigorje and in 19 wells (N?=?174 samples) in Podravina from 2002 to 2007. In Podravina, the nitrate content was 24.9 mg/l and 6 % of the samples were above the maximum available value (MAV), and in Prigorje the content was 53.9 mg/l and 38 % of the samples above MAV. The wells were classified as correct, occasionally incorrect and incorrect. In the group of occasionally incorrect and incorrect wells, the point sources were within 10 m of the well. There is no statistically significant difference over the years or seasons within the year, but the interaction between locations and years was significant. Nitrate concentrations’ trend was not significant during the monitoring. These results are a prerequisite for the adjustment of Croatian standards to those of the EU and will contribute to the implementation of the Nitrate Directive and the Directives on Environmental Protection in Croatia and the EU.     

Occurrence of haloacetic acids (HAAs) and trihalomethanes (THMs) in drinking water of Taiwan

In this study, water samples were collected from 86 water treatment plants for analysis of haloacetic acids (HAAs) and trihalomethanes (THMs) from February to March, 2007 and from July to August, 2007. Both seasonal and geographical variations of disinfection by-products (DBPs) in drinking water of Taiwan were presented. The results showed that the five HAA concentrations (HAA5) were 1.0–38.9 μg/L in the winter and 0.2–46.7 μg/L in the summer; and the total THMs were ND-99.4 μg/L in the winter and ND-133.2 μg/L in the summer. For samples taken from the main Taiwan island, dichloroacetic acid (29.4–31.7%) and trichloroacetic acid (25.3–27.6%) were the two major HAA species, and trichloromethane was the major THM species (49.9–62.2%) in finished water. For water treatment plants located on the offshore islands outside of Taiwan, high bromide concentration was found in raw water, and higher percentage of brominated THMs and HAAs were formed in the overall formation. A statistically significant (P?<?0.005) logarithmic linear regression model was found to be useful to describe the correlations between TTHM and HAA5 or nine HAAs (HAA5?=?1.219 ×TTHM ^0.754, R ²?=?0.658; HAA9?=?1.824 ×TTHM ^0.735, R ²?=?0.678). No apparent difference was observed for DBPs concentrations between finished water and distribution samples in this study.     

Surface acoustic wave (SAW) microsensor array for measuring VOCs in drinking water

Exposure to volatile organic chemicals (VOCs) in drinking water has been linked to a number of adverse health effects including cancer, liver, and kidney damage. However, the large number of potential contaminants and the cost and complexity of existing analytical methods limits the extent to which water quality is routinely characterized. This project focused on the laboratory development and evaluation of an instrument for field analysis of VOCs in drinking water. The instrument is based on an array of six polymer-coated surface-acoustic-wave microsensors. A test-set consisting of dichloromethane, chloroform, 1,1,1-trichloroethane, perchloroethylene, and m-xylene was used in a series of experiments designed to optimize the purge-trap preconcentration system, calibrate the instrument over the concentration range of 0.2-2 times the USEPA maximum contaminant levels (MCLs), and compare results to those of a reference laboratory. The primary goal was to develop a cost-effective alternative for on-site evaluation of VOCs in water. Calibration and evaluation test results for spiked water samples demonstrate adequate sensitivity for 19 of the 21 regulated VOCs considered using a ten minute sampling and analysis cycle. Monte Carlo simulations characterized the performance of trained artificial neural networks (ANNs) which had correct classification rates of 99%, 90%, and 80% for the five individual test-set vapors and their binary and ternary mixtures, respectively. These results demonstrate the excellent potential of this technology for addressing the need for improved VOC field-screening methods for water supplies.     

Oxidation of Cr(III) to Cr(VI) during chlorination of drinking water

Drinking water treatment typically uses strong oxidants such as chlorine which are capable of converting Cr(III) to Cr(VI). The rates and extent of Cr(III) oxidation by chlorine are not well established. Cr(III) oxidation experiments were therefore conducted in distilled deionized water and New York City tap water dosed initially with Cr(III) and supplemented with sodium hypochlorite to increase free chlorine residual. Reaction progress was monitored using capillary electrophoresis which quenched reactions and allowed for quantification of Cr(VI). Three different forms of Cr(III) were used as reactants: a Cr(III) nitrate salt, Cr(III)-EDTA, and Cr(III) hydroxide. Rates of Cr(VI) production for all three forms of Cr(III) were rapid, on the order of hours. However, oxidation rates slowed and a plateau in Cr(VI) concentrations was reached. This resulted in less than 100% conversion of Cr(III) to Cr(VI) even at relatively high chlorine doses (10 to 100 mg L(-1) as Cl(2)). The loss of free chlorine due to a non-Cr chlorine demand, the precipitation of Cr(III) to Cr(OH)(3)(s), and the partial oxidation of Cr(III) to intermediate oxidation states (i.e. Cr(IV) and Cr(V)) were examined and eliminated as possible explanations for this behavior. Consumption of chlorine via reaction with intermediate oxidation states of Cr is therefore offered as a possible explanation for the plateau in Cr(VI) concentrations.     

Mechanistic studies of N-nitrosodimethylamine (NDMA) formation in chlorinated drinking water

Studies were conducted to investigate the hypothesis that N-nitrosodimethylamine (NDMA) is a potential disinfection by-product specifically produced during chlorination or chloramination. Experiments were conducted using dimethylamine (DMA) as a model precursor. NDMA was formed by the reaction of DMA with free chlorine in the presence of ammonia and also with monochloramine. We proposed a mechanism for NDMA formation in chlorinated or chloraminated water, which does not require nitrite as in N-nitrosation. The critical NDMA formation reactions consist of (i) the formation of monochloramine by combination of free chlorine with ammonia, (ii) the formation of 1,1-dimethylhydrazine (UDMH) intermediate from the reaction of DMA with monochloramine followed by, (iii) the oxidation of UDMH by monochloramine to NDMA, and (iv) the reversible chlorine transfer reaction between free chlorine/monochloramine and DMA which is parallel with (i) and (ii). A kinetic model was also developed to validate the proposed mechanism.     

Iodide-assisted total lead measurement and determination of different lead fractions in drinking water samples

Lead and its compounds are toxic and can harm human health, especially the intelligence development in children. Accurate measurement of total lead present in drinking water is crucial in determining the extent of lead contamination and human exposure due to drinking water consumption. The USEPA method for total lead measurement (no. 200.8) is often used to analyze lead levels in drinking water. However, in the presence of high concentration of the tetravalent lead corrosion product PbO(2), the USEPA method was not able to fully recover particulate lead due to incomplete dissolution of PbO(2) particles during strong acid digestion. In this study, a new procedure that integrates membrane separation, iodometric PbO(2) measurement, strong acid digestion and ICP-MS measurement was proposed and evaluated for accurate total lead measurement and quantification of different lead fractions including soluble Pb(2+), particulate Pb(II) carbonate and PbO(2) in drinking water samples. The proposed procedure was evaluated using drinking water reconstituted with spiked Pb(2+), spiked particulate Pb(II) carbonate and in situ formed or spiked PbO(2). Recovery tests showed that the proposed procedure and the USEPA method can achieve 93-112% and 86-103% recoveries respectively for samples containing low PbO(2) concentrations (0.018-0.076 mg Pb per L). For samples containing higher concentrations of PbO(2) (0.089-1.316 mg Pb per L), the USEPA method failed to meet the recovery requirement for total lead (85-115%) while the proposed method can achieve satisfactory recoveries (91-111%) and differentiate the soluble Pb(2+), particulate Pb(II) carbonate and PbO(2).     

Heavy metals concentrations in zooplankton and suspended particulate matter in a southwestern Atlantic temperate estuary (Argentina)

The present work includes part of the first studies of metals concentrations in the zooplankton from a heavily industrialized estuary of Argentina, the Bahía Blanca estuary. Cd, Cu, and Pb concentrations in the zooplankton (macro- and mesozooplankton) and the suspended particulate matter were measured at stations with different degree of pollution. Physicochemical variables and zooplankton composition and abundance were also analyzed. Thus, the aim of the present work was to analyze the spatial and temporal distribution of heavy metals in these two different fractions, and the possible relation among them due to their importance in the biogeochemical cycles of marine environments. Samplings were carried out during a year, from March 2005 to April 2006, every 2 months, at stations located near chemical and petrochemical industries, stations far from these points and one station in an intermediate location. In the mesozooplankton, the mean concentrations of Cd, Cu, and Pb were 3.63?±?1.46, 34.46?±?5.40, and 11.54?±?3.04 μg?g^?1 dry weight (d.w.) respectively, while in the macrozooplankton, 3.20?±?2.28, 21.86?±?4.79, and 8.36?±?1.85 μg?g^?1 d.w. On the other hand, particulate Cd, Cu, and Pb presented a mean concentration of 3.33?±?1.22, 12.75?±?2.67, and 12.53?±?3.20 μg?g^?1 d.w., respectively. Metals’ levels in both the SPM and zooplankton fluctuated throughout the study time and were relatively high in the particulate phase especially for Cu and Pb. Moreover, zooplankton accumulated important concentrations of the three metals. The sources of them are probably the discharges of the industries and domestic sewages located near the estuary.     

Exploring data quality for some inorganic and organic constituents of inhalable particulate matter (PM10)

Quality assurance (QA) assessments of air pollution data sets provide a basis for evaluating the significance of various substances in the atmosphere. For non-criteria pollutants, QA results are seldom reported in the technical literature and are often difficult to estimate. The present report provides a summary of QA results such as recovery, precision and accuracy data. Of the six trace elements and nine organic constituents compared in detail, recoveries, laboratory precision and laboratory accuracy values were 100%, ±3% to ±19% and-2 to-13% for the former group and 69% to 98%, ±7% to 23% and-15 to-34% for the later group. System precision varied from ±22% to ±47% for the trace elements and ±42% to ±83% for the organic constituents. Limitations in the interpretation of non-criteria particulate-phase pollutant data bases are discussed with some emphasis placed on receptor-modelling and risk assessment applications. Finally, the relevance of NBS certified materials for QA estimates in non-criteria air pollutant studies is also reviewed.     

Assessment of lead, zinc, copper, nickel and chromium in total suspended particulate matter from the workplace in Al-Rusayl Industrial Estate, Oman

Total suspended particulates (TSP) were collected with a high volume sampler from the indoor work environment of 23 industries in Al-Rusayl Industrial Estate in Muscat, Oman. The values measured ranged from 39 microg m(-3) to 1033 microg m(-3). TSP in the ambient air of the area was found to have an average value of 1802 microg m(-3). TSP were analyzed for Pb, Cu, Ni, Zn and Cr. Compared to other metals, Pb emission was high with values ranging from 3 to 15 109 ng m(-3) with the mean value being 1 293 ng m(-3); Cu concentration varied from 3 to 2600 ng m(-3) with a mean value of 131 ng m(-3); Ni concentration ranged from 6 to 46 ng m(-3) with a mean value of 17 ng m(-3); Cr concentration ranged from 1 to 133 ng m(-3) with a mean value of 23 ng m(-3) while that of Zn varied from 0.01 to 1 978 ng m(-3) with the mean value being 464 ng m(-3). The concentrations of Pb, Ni, Cu, Cr, and Zn in the ambient air were also measured and found to have the following values: 122, 18, 16, 5 and 0.01 ng m(-3), respectively. These values indicate that the industries in the area do not contribute significantly to heavy metal air pollution.     

Characterization of elemental pollution and its variations in sediments and suspended particulate matter from the River Elbe via multi-element analysis combined with chemometric data evaluation

Sediments and suspended particulate matter taken from about 100 sampling sites along the River Elbe from the source to the mouth during the period 1992 and 1998 have been analyzed for the concentrations of more than 60 elements in each sample. The analytical data were subsequently processed by means of multivariate statistics in order to characterize the charge of the River Elbe with inorganic pollutants to elucidate pollution trends. Using factor analysis 18 elements were found to be enriched by human activities. By means of cluster analysis--using the 18 anthropogenically influenced elements as variables--the sampling sites were aggregated into groups having similar element distributions. Thus, the entire stretch of the River Elbe was divided into three sections of characteristic elemental pollution. Finally, the trends in anthropogenic pollution within the characteristic regions since the early nineties were assessed. It turned out that most of the anthropogenically influenced elements showed a decrease in the upper and middle parts of the river, whereas no decrease could be verified in the estuary region.     

Estimation of uranium and radon concentration in some drinking water samples of Upper Siwaliks, India

Uranium and radon concentration was assessed in water samples taken from hand pumps, natural sources and wells collected from some areas of Upper Siwaliks, Northern India. Fission track registration technique was used to estimate the uranium content of water samples. The uranium concentration in water samples was found to vary from 1.08 +/- 0.03 to 19.68 +/- 0.12 microg l(-1). These values were compared with safe limit values recommended for drinking water. Most of the water samples were found to have uranium concentration below the safe limit of 15 microg l(-1) (WHO, World Health Organization, Guidelines for drinking-water quality (3rd ed.). Geneva, Switzerland: WHO, 2004). The radon estimation in these water samples was made using alpha-scintillometry to study its correlation with uranium. The radon concentration in these samples was found to vary from 0.87 +/- 0.29 to 32.10 +/- 1.79 Bq l(-1). The recorded values of radon concentration were within the recommended safe limit of 4 to 40 Bq l(-1) (UNSCEAR, United Nations Scientific Committee on the Effects of Atomic Radiations, Sources and effects of ionizing radiation. New York: United Nations, 1993). No direct correlation was found between uranium concentration and radon concentration in water samples belonging to Upper Siwaliks. The values of uranium and radon concentration in water were compared with that from the adjoining areas of Punjab state, India.     

Distributions, sources, and ecological risks of DDT-related contaminants in water, suspended particulate matter, and sediments from Haihe Plain, Northern China

The residual levels of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including p,p′-DDT, DDD, and DDE) in water, suspended particulate matter (SPM), and sediments from major rivers, lakes, and reservoirs in Haihe Plain were measured with a gas chromatograph equipped with a ⁶³Ni microelectron capture detector. In the fall of 2004, the contents of the total DDXs in the water and SPM were 0.29?±?0.69 ng L^?1 and 423.13?±?577.85 ng g^?1 dry wt., respectively. In the spring of 2005, the total DDXs were 0.36?±?0.91 ng L^?1 for water and 35.93?±?62.65 ng g^?1 dry wt. for SPM. The average concentration of DDXs for sediments was 7.10?±?7.57 ng g^?1 dry wt. during the two seasons. The Eastern-Hebei-Province Coastland River System was the most polluted, which was mainly attributable to the extensive use of DDT pesticide and dicofol in that system. Recent DDT inputs still occur in some regions, as indicated by DDT/(DDD + DDE) > 1 at 29–36 % of the sites for water and 55–61 % of the sites for SPM. The potential ecological risks of DDT in the water were assessed using a species sensitivity distribution model. Only shrimp and crabs were found to have potentially affected fraction values of 1.63?×?10^?3 to 2.27?×?10^?4, with probabilities beyond the hazardous concentration for 5 % of species (HC5) values of 1.90–2.56 %, suggesting only slight risks. DDXs in the sediments of some sites were also of potential risk to benthic organism based on consensus-based sediment quality guidelines.     

Diversity and dynamics of the Vibrio community in well water used for drinking in Guinea-Bissau (West Africa)

Bacteria of the genus Vibrio are ubiquitous in aquatic environments and can be found either in culturable or in a viable but nonculturable (VBNC) state. The genus comprises many pathogenic species accountable for water and food-borne diseases that prove to be fatal, especially in developing countries, as in Guinea-Bissau (West Africa), where cholera is endemic. In order to ascertain the abundance and structure of Vibrio spp. community in well waters that serve as the sole source of water for the population, quantitative polymerase chain reaction (qPCR), PCR-denaturant gradient gel electrophoresis (DGGE), and cloning approaches were used. Results suggest that Vibrio spp. were present throughout the year in acidic, freshwater wells with a seasonal community composition shift. Vibrio spp. abundance was in accordance with the abundance found in coastal environments. Sequences closely related to pathogenic Vibrio species were retrieved from well water revealing exposure of the population to such pathogens. pH, ammonium, and turbidity, regulated by the rain pattern, seem to be the variables that contributed mostly to the shaping and selection of the Vibrio spp. community. These results reinforce the evidence for water monitoring with culture-independent methods and the clear need to create/recover water infrastructures and a proper water resources management in West African countries with similar environmental conditions.     

Comparative cancer risk assessment of THMs in drinking water from well water sources and surface water sources

This research evaluates the lifetime cancer risks from trihalomethanes in Tehran's drinking water. The Trihalomethanes were measured in seven different water districts. Sixty-three samples were taken from tap water across the city for 7 months. The samples were analyzed for trihalomethanes using US EPA method 524.2. The average concentration of total trihalomethanes in different districts were between 0.81 and 9.0 μg/L, and the highest concentrations were detected in district 2 at 19.5 μg/L. Total lifetime cancer risks assessment from exposure to trihalomethanes in drinking water (ingestion, inhalation, and skin routes) were performed for people living in different districts in Tehran. The lifetime cancer risk was 7.19 × 10(-5) in district 2 (a more affluent neighborhood) where mostly surface water sources is used to supply drinking water and 9.38 × 10(-6) in district 7 (a less affluent neighborhood) which is mainly supplied with well water sources. Based on the population data, the total expected lifetime cancer cases from exposure to trihalomethanes are 104, 108, 81, 81, 41, 27, and three for districts 1 through 7, respectively. The average lifetime cancer risk was 4.33 × 10(-5) which means a total of 606 lifetime cancer cases for the entire province of Tehran. The highest risk from THMs seems to be from the inhalation route followed by ingestion and dermal contacts.     

Bioluminescent yeast estrogen assay (BLYES) as a sensitive tool to monitor surface and drinking water for estrogenicity

Estrogenic Endocrine Disrupting Chemicals (EDCs) are a concern due to their ubiquity and recognized adverse effects to humans and wildlife. Methods to assess exposure to and associated risks of their presence in aquatic environment are still under development. The aim of this work is to assess estrogenicity of raw and treated waters with different degrees of pollution. Chemical analyses of selected EDCs were performed by liquid chromatography-tandem mass spectrometry, and estrogenic activity was evaluated using in vitro bioluminescent yeast estrogen assay (BLYES). Most raw water samples (18/20) presented at least one EDC and 16 rendered positive in BLYES. When EDCs were detected, the bioassay usually provided a positive response, except when only bisphenol A was detected at low concentrations. The highest values of estrogenic activity were detected in the most polluted sites. The maximum estrogenic activity observed was 8.7 ng equiv. of E2 L(-1). We compared potencies observed in the bioassay to the relative potency of target compounds and their concentrations failed to fully explain the biological response. This indicates that bioassay is more sensitive than the chemical approach either detecting estrogenic target compounds at lower concentrations, other non-target compounds or even synergistic effects, which should be considered on further investigations. We have not detected either estrogenic activity or estrogenic compounds in drinking water. BLYES showed good sensitivity with a detection limit of 0.1 ng equiv. E2 L(-1) and it seems to be a suitable tool for water monitoring.     

2007-2013年乌鲁木齐市集中式饮用水源地水质变化趋势分析及对策建议

对2007-2013年乌鲁木齐市集中式饮用水源地水质监测数据进行综合分析,泉水型地下饮用水源地米东区三水厂受储水介质及当地地质化学结构的影响,溶解盐类常年超标,水质较差;湖库型地表水源地五、八水厂总磷浓度在个别年份存在一定程度的超标现象,且地表水源地中挥发性卤代烃类、硝基苯和酞酸酯类等有机项目及镍等重金属类检出率较高,存在一定程度的风险。对此提出了进一步完善水源地环境保护及合理开发优质水资源的对策建议,为首府饮用水源地的保护和相关研究工作提供依据。