Evaluation of vacuum filter sock surface sample collection method for Bacillus spores from porous and non-porous surfaces

Vacuum filter socks were evaluated for recovery efficiency of powdered Bacillus atrophaeus spores from two non-porous surfaces, stainless steel and painted wallboard and two porous surfaces, carpet and bare concrete. Two surface coupons were positioned side-by-side and seeded with aerosolized Bacillus atrophaeus spores. One of the surfaces, a stainless steel reference coupon, was sized to fit into a sample vial for direct spore removal, while the other surface, a sample surface coupon, was sized for a vacuum collection application. Deposited spore material was directly removed from the reference coupon surface and cultured for enumeration of colony forming units (CFU), while deposited spore material was collected from the sample coupon using the vacuum filter sock method, extracted by sonication and cultured for enumeration. Recovery efficiency, which is a measure of overall transfer effectiveness from the surface to culture, was calculated as the number of CFU enumerated from the filter sock sample per unit area relative to the number of CFU enumerated from the co-located reference coupon per unit area. The observed mean filter sock recovery efficiency from stainless steel was 0.29 (SD = 0.14, n = 36), from painted wallboard was 0.25 (SD = 0.15, n = 36), from carpet was 0.28 (SD = 0.13, n = 40) and from bare concrete was 0.19 (SD = 0.14, n = 44). Vacuum filter sock recovery quantitative limits of detection were estimated at 105 CFU m(-2) from stainless steel and carpet, 120 CFU m(-2) from painted wallboard and 160 CFU m(-2) from bare concrete. The method recovery efficiency and limits of detection established in this work provide useful guidance for the planning of incident response environmental sampling for biological agents such as Bacillus anthracis.     

Performance of poly(vinyl alcohol) gel columns on the ion chromatographic determination of perchlorate in fertilizers

Interest in possible sources of perchlorate (ClO4) that could lead to environmental release has been heightened since the Environmental Protection Agency placed this anion on its Contaminant Candidate List for drinking water. Although recent investigations have suggested that fertilizers are minor contributors to environmental perchlorate contamination overall, there is still interest in screening commercial products for possible contamination and quantitating perchlorate when it is found. Ion chromatography (IC) has been used for this application owing to its speed, low detection limits, widespread availability, and moderate ruggedness relative to other techniques. However, fertilizer matrixes complicate the IC analysis relative to potable water matrixes. In this study, the performance of poly(vinyl alcohol) gel resin IC columns (100 mm and 150 mm) was evaluated for fertilizer matrixes using method EPA/600/R-01/026. The NaOH eluent included an organic salt, sodium 4-cyanophenoxide. Detection was by suppressed conductivity. A set of 55 different field samples representing 48 products and previously used by the EPA to assess occurrence of perchlorate in fertilizers (EPA/600/R-01/049) was reanalyzed on the 150 mm column. The 100 mm column was used to further investigate the positive hits. Both columns gave satisfactory performance in fertilizer matrixes, with spike recoveries (+/- 15%), assured reporting levels (0.5-225 microg g(-1) except for one at 1,000 microg g(-1)), accuracy (relative error < 30% always and most < 15%), and precision [injection-to-injection reproducibility < 3% relative standard deviation (RSD)] comparable to those reported in other studies. Performance did not vary substantially between column lengths. Lastly, the results of this investigation provided further evidence in support of the conclusions that had been reached previously by the EPA on the occurrence of perchlorate in fertilizers.     

A field test for the assessment of faecal contamination of potable water

A simple, sensitive, rapid, inexpensive paper strip impregnated with Salmonellal E. coli medium (SEM) was formulated, and placed in a test tube. When potable water of 10 ml was added to the test tube it detected the faecal contamination of water samples within 16-48 h when incubated at room temperature from 20 to 35 degrees C. The positive results were indicated when the medium turned black (hydrogen sulfide production) for the presence of Salmonella sp. and/or the formation of a red ring (free indole from tryptophan) when a few drops of Kovac's reagent was added for the presence of coliform bacteria (E. coli). More than 600 water samples were tested with the new test (SEM) and results showed 99% agreement with that of the standard most probable number (MPN) coliform test and also proved highly successful in the field when it was employed to detect both Salmonella and E. coli. Different water testing laboratories involved in a water quality monitoring programme and governmental agencies evaluated the test media and reported that the test was user friendly, reliable and simple to perform in the field and will be especially useful for screening of both urban and rural water supplies for routine monitoring of bacteriological contamination.     

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.     

Hydrology-linked spatial distribution of pesticides in a fjord system in Greenland

A pilot study is presented evaluating selected chlorinated pesticides as chemical tracers for water masses in a sub-Arctic fjord system (Godth?bsfjord, western Greenland). Polyoxymethylene (POM) based passive water samplers were deployed during summer-autumn 2010. The levels of the analysed chlorinated pesticides in the fjord surface waters were found to be low compared to earlier studies. α-Hexachlorocyclohexane (α-HCH) and hexachlorobenzene (HCB) were the predominant contaminants. However, these two compounds have higher levels in oceanic water compared to freshwater influenced fjord waters. These chemicals can thus be considered as indicators for direct atmospheric long-range transport, while the organochlorine pesticides like trans-, cis-chlordane, trans-nonachlor and oxychlordane that are detected in the inner parts of the fjord are indicators for potential freshwater sources such as rivers and glacial meltwater runoff (secondary sources). The average values were 50 pg L(-1) for HCB and 11 pg L(-1) for α-HCH. These concentrations are comparable to levels in fjords in Svalbard (Norwegian Arctic), but lower than in open and/or ice covered oceans in the Canadian Arctic. Two air samplers were deployed for the identification of direct atmospheric contributions. Local contamination sources do not contribute significantly. The study demonstrated the value of passive water sampling devices for comprehensive hydrological characterization of Arctic coastal waters.     

Transport and fate of organochlorine pesticides in the River Wuchuan,southeast China

Persistent organic pollutants (POPs) such as chlorinated pesticides are of global concern due to their widespread occurrence, persistence, bioaccumulation and toxicity to animals and human. This paper summarises recent research on 18 chlorinated pesticides in an important catchment in China, by determining their concentrations and behaviour in water, sediment, soil and plants. The concentrations of the total pesticides were in the ranges 187-893 ng l(-1) in river water, 8.53-210 ng g(-1) dry weight in soil, 2.66-13.45 ng g(-1) dry weight in river sediment, and 651-2823 ng g(-1) dry weight in plants. The predominance of beta-HCH as the major isomer of HCHs in all water, soil, sediment and plant samples was clearly observed, due to beta-HCH's resistance to biodegradation. On average beta-HCH accounted for 44%, 53%, 50%, and 46% of the total HCH concentration in water, soil, sediment and plant, respectively. Of the DDTs, DDE accounted for 48%, 43%, 53%, 55% of the total DDT, which suggested that DDT had been transformed to its metabolites, DDE and DDD, of which DDE was the more stable. The chlorinated pesticide levels in the River Wuchuan were generally below the guideline values in China, but some sites displayed levels in excess of EC Environmental Quality Standards for HCHs and DDTs. The results therefore provide important information on the current contamination status of a key agricultural watershed in China, and point to the need for urgent actions to evaluate the long-term fate and toxicity of such persistent compounds and an appropriate remediation strategy.     

中国沿海三省主要饮用水源有机物监测

采用固相萃取、吹扫捕集和气相色谱-质谱联用仪(GC-MS)对江苏、浙江、山东省的21个主要地表饮用水源、126份水样中的25种VOCs、38种SVOCs进行定量检测。结果有19种VOCs、10种SVOCs至少在一个水源地多次被检出,其中挥发性氯代烃、苯系物、氯代苯类、酚类、硝基苯类、酞酸酯类、农药为中国或美国环境保护局提出的"水中优先控制污染物",最高检出量为27.79μg/L。三省主要地表水受到有机物轻度污染,水体中VOCs、SVOCs含量尚未超过《地表水环境质量标准》(GB 3838-2002)和《生活饮用水卫生标准》(GB 5749-2006)限值,工业废水排放及农田雨水径流是地表水有机物的重要来源。     

Evaluation of interference to conventional and real-time PCR for detection and quantification of fungi in dust

Advances in polymerase chain reaction (PCR) have permitted accurate, rapid and quantitative identification of microorganisms in pure cultures regardless of viability or culturability. In this study, a simple sample processing method was investigated for rapid identification and quantification of fungal spores from dust samples using both conventional and real-time PCR. The proposed method was evaluated for susceptibility to interference from environmental dust samples. Stachybotrys chartarum and Aspergillus fumigatus were used as test organisms. The sensitivity of detection in pure culture was 0.1 spore DNA equivalents per PCR reaction corresponding to 20 spores ml(-1) in the sample. However, 1 spore DNA equivalent per PCR reaction corresponding to 200 spores ml(-1) in the sample was the lowest amount of spores tested without interference in dust samples spiked with spores of either fungal species. The extent of inhibition was calculated using conventional and real-time PCR reactions containing fungal spores, specific primers, specific probes (for real-time PCR) and various amounts of dust. The results indicate that the extent of inhibition by dust on PCR varies with the type and amount of dust, and number of spores. No interference in the analysis of spiked samples was detected from 0.2 mg ml(-1) of four real-life dust samples at p-value >0.05 using 2 x 10(4) spores for conventional PCR and 2 x 10(5) spores for real-time PCR. However, samples containing >0.2 mg ml(-1) real-life dust compromised the PCR assay. These results suggest the potential usefulness of a simple sample processing method in conjunction with PCR for monitoring the fungal content of aerosols collected from indoor environments.     

Analysis of short-chain chlorinated paraffins: a discussion paper

Short-chain chlorinated paraffins are a class of organic compounds widely used in many industrial applications, extensively diffused into the environment, persistent, bioaccumulative, and toxic towards aquatic organisms. However, their study and monitoring in the environment are still limited. Because of the enormous number of positional isomers that characterise their mixtures, the analysis of this class of pollutants is very difficult to perform. Beside this, the lack of certified reference materials poses a problem for the assessment of the quality assurance/quality control of any analytical procedure. At present, the scientific community does not agree on any analytical reference method, although the monitoring of short-chain chlorinated paraffins has already started in order to comply with the Water Framework Directive of the European Union on water quality. In this paper the regulatory framework, in which chlorinated paraffins are included, and the status concerning their determination are summarized. The main analytical difficulties still existing are discussed, and the definition of a method-defined parameter as well as the development of a standardised method are suggested as a way to obtain comparable monitoring data.     

Nitrate occurrence in the groundwater of the Loukkos perimeter

This study assesses the occurrence of nitrate in the groundwater beneath the R'mel area of the Loukkos perimeter (north-west Morocco), which covers an approximate area of 2,560 km2 and is located between the towns of Ksar el Kebir and Larache. It also borders the Atlantic Ocean. Groundwater supplies are the principal source of drinking water in this region and there is no public drinking water network in the rural area. This perimeter has a population of about 500,000 inhabitants of which the rural population represents 60%, many of whom have depended on and used the water from the aquifers for many years. The inhabitants and farmers depend on the groundwater supplies for drinking water, crop irrigation and other uses. The plain provides the ideal conditions for agriculture and the use of chemical fertilisers has been increasing. In this study, 53 water samples were collected from wells and springs. Each well or spring was sampled once or twice during 1998-2000. Nitrate concentrations ranged from extremely low up to 144 mg L(-1). Nitrate concentrations exceeded the maximum contaminant level (MCL) of 50 mg L(-1) in 12 of the 53 groundwater samples (23%), whereas 31 of the 53 samples (58%) had nitrate concentrations of less than 25 mg L(-1).     

Investigation of reagent distributions on glass fiber membrane filters used in air sampling

This project has arisen from the need to produce GFFs (glass fiber filters) bearing a thin and evenly distributed coating of a selected reagent in the equatorial plane for breakthrough studies. However, it has been discovered that today's two general techniques for coating GFFs (total immersion and application of reagent solution to GFFs) have usually produced unevenly distributed coatings of reagent in the equatorial plane. In addition, quantities of reagent on GFFs from commercial sources may vary widely in the same lot of coated GFFs. Consequences are variability in capacity of coated filters at the point of breakthrough and, perhaps, wasted reagent. Although today's reagent-coated filters may be satisfactory for routine air sampling, such filters may be unacceptable for precise breakthrough studies. Research has been conducted successfully to produce nearly evenly distributed coatings of reagents in the equatorial plane of GFFs by application of reagent solutions to the centers of GFFs which are resting on crisscrossing, fine, stainless-steel wire. Distributions of coatings have been determined by punching out twenty-one 5-mm circles from each GFF and analyzing each circle by flow-injection with a UV detector. Lowest achievable relative standard deviations of measurement (RSDs) for reagents in 5-mm circles have been 5 to 7%. Reagents studied have included 1-(2-pyridyl)piperazine (1-2PP), 2,4-dinitrophenylhydrazine (DNPH), and 1-(9-anthracenylmethyl)piperazine (MAP). Factors affecting the distribution of such coatings include choice of reagent and choice of solvent for the reagent solution.     

快速溶剂萃取—气相色谱法分析土壤中的20种有机氯

采用加速溶剂萃取—气相色谱法对土壤中20种有机氯农药进行了提取测定.通过改变加速溶剂萃取条件,选取了最佳条件参数,减少了组份的损失;通过改变气相色谱条件,使得20种有机氯农药快速分离.该方法具有操作简便、灵敏度高、检出限低、快速、溶剂消耗少等优点,方法检出限为1.23～ 3.11 μg/kg,实际样品的加标回收率为62.3％～119.7％.     

梯度淋洗离子色谱法测定饮用水中6种阴离子

采用离子色谱法同时测定饮用水中F-、Cl-、Br-、NO3-、SO24-、PO34-等6种阴离子,水样经0.22μm滤膜过滤,自动淋洗发生器产生20 mmol/L～40 mmol/L KOH淋洗液梯度洗脱,在流量0.25 mL/min条件下采用IonPac AG19保护柱和IonPac AS19分离柱分离和定量。方法线性良好,6种阴离子的检出限为0.005 mg/L～0.057 mg/L,标准溶液平行测定6次,测定值的RSD在0.5%～2.2%之间,水样加标回收率在83%～106%之间。     

Evaluation of the presence-absence (P-A) test: A simplified bacteriological test for detecting coliforms in rural drinking water of India

One thousand three-hundred and ninety-four drinking water sources comprising ground water, surface water and piped supplies were tested in order to compare the presence-absence (P-A) test with standard MPN method to detect coliforms as indicators of water quality. Out of 1394 samples, 1074 (77.04%) and 1030 (74.88%) were positive by the MPN and P-A test, respectively. The P-A test detected 96% of the positives detected by the MPN test. The P-A test may be effectively used as a rapid screening method to detect coliform contamination in less polluted sources such as ground water and piped supplies.     

Nitrate,sulphate and chloride contents in public drinking water supplies in Sicily,Italy

Water samples collected from public drinking water supplies in Sicily were analysed for electric conductivity and for their chloride, sulphate and nitrate contents. The samples were collected as uniformly as possible from throughout the Sicilian territory, with an average sampling density of about one sample for every 7,600 inhabitants. Chloride contents that ranged from 5.53 to 1,302 mg/l were correlated strongly with electric conductivity, a parameter used as a proxy for water salinity. The highest values are attributable to seawater contamination along the coasts of the island. High chloride and sulphate values attributable to evaporitic rock dissolution were found in the central part of Sicily. The nitrate concentrations ranged from 0.05 to 296 mg/l, with 31 samples (4.7% of the total) exceeding the maximum admissible concentration of 50 mg/l. Anomalous samples always came from areas of intensive agricultural usage, indicating a clear anthropogenic origin. The same parameters were also measured in bottled water sold in Sicily, and they all were within the ranges for public drinking water supplies. The calculated mean nitrate intake from consuming public water supplies (16.1 mg/l) did not differ significantly from that of bottled water (15.2 mg/l). Although the quality of public water supplies needs to be improved by eliminating those that do not comply with the current drinking water limits, at present it does not justify the high consumption of bottled water (at least for nitrate contents).     

Filtration of fullerene and copper oxide nanoparticles using surface-modified microfilters

This study evaluated the filtration of engineered nanoparticles of fullerene and copper oxide (CuO) from water by using surface-modified microsized filters. The surfaces of microsized filters of cellulose acetate and glass fibers were coated with cationic and anionic surfactants to give them positively and negatively charged surfaces, respectively. Uncoated microfilters removed 30 % of a fullerene suspension, while no nanosized CuO suspension was removed. Cationic surfactant-coated filters enhanced the removal efficiency up to 70 % for the fullerene suspension, while the anionic surfactant-coated filters could not remove fullerene at all. The positively charged filters with cationic surfactant coating could easily adsorb negatively charged fullerenes on their surfaces. However, none of the surfactant-coated filters removed the CuO nanoparticles because the nanoparticles were not affected by the electrical charge of the filtration medium. The Hamaker constants of nanoparticles interacting with the filter materials in water were calculated to study these interactions. The Hamaker constant of fullerene interacting with cellulose acetate in water, 4.68E???21 J, was higher than that of interacting with quartz in water, 2.59E???21 J. However, the Hamaker constants of CuO interacting with quartz and cellulose acetate in water were both negative values, implying repulsive van der Waals interactions. The curves of potential energy of interaction between nanoparticles and the various filter media implied that the nanoparticles were very stable in water, and so, natural deposition of nanoparticles on the filters would not occur. Therefore, electrical bonding and hydrophobic interactions were the forces dominating fullerene removal by positively charged filters.     

Penetration of polar brominated DBPs through the activated carbon columns during total organic bromine analysis

Total organic bromine (TOBr) is a collective parameter representing all the brominated organic disinfection byproducts (DBPs) in water samples. TOBr can be measured using the adsorption-pyrolysis method according to Standard Method 5320B. This method involves that brominated organic DBPs are separated from inorganic halides and concentrated from aqueous solution by adsorption onto the activated carbon (AC). Previous studies have reported that some commonly known brominated DBPs can partially penetrate through the AC during this adsorption step. In this work, the penetration of polar brominated DBPs through AC and ozone-modified AC was explored with two simulated drinking water samples and one chlorinated wastewater effluent sample. Polar brominated DBPs were selectively detected with a novel precursor ion scan method using electrospray ionization-triple quadrupole mass spectrometry. The results show that 3.4% and 10.4% of polar brominated DBPs (in terms of total ion intensity) in the chlorinated Suwannee River fulvic acid and humic acid samples, respectively, penetrated through the AC, and 19.6% of polar brominated DBPs in the chlorinated secondary wastewater effluent sample penetrated through the AC. The ozone-modification of AC minimized the penetration of polar brominated DBPs during the TOBr analysis.     

气相色谱法测定地下水中氯化苄

建立了气相色谱法测定地下水中氯化苄的方法。选用ＧＤＸ５０２大孔树脂或Ｃ１８小预处理柱吸附浓缩地下水中氯化苄，用苯洗脱，洗脱液注入色谱仪进行分析。方法回收率为８６４９８１％，变异系数＜８％。     

固相萃取-高效液相色谱法测定水中氯酚类化合物

采用固相萃取-高效液相色谱法测定水中7种氯酚类化合物,Waters OASIS WAX柱萃取效率最高,最佳萃取时间和洗脱时间分别为60和5 min。该法的线性范围为1.0~40 mg/L,检出限为0.015~0.5μg/L,精密度为0.558%~2.22%,回收率为83.2%~105%。该法适用于地表水及饮用水中氯酚类化合物的检测。     

Solid phase extraction of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) ions with 1-(2-thiazolylazo)-2-naphthol loaded Amberlite XAD-1180

A new method for separation and preconcentration of trace amounts of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) ions in various matrices was proposed. The method is based on the adsorption and chelation of the metal ions on a column containing Amberlite XAD-1180 resin impregnated with 1-(2-thiazolylazo)-2-naphthol (TAN) reagent prior to their determination by flame atomic absorption spectrometry (FAAS). The effect of pH, type, concentration and volume of eluent, sample volume, flow rates of sample and elution solutions, and interfering ions have been investigated. The optimum pH for simultaneous retention of all the metal ions was 9. Eluent for quantitative elution was 20 ml of 2 mol l(-1) HNO(3). The optimum sample and eluent flow rates were found as 4 ml min(-1), and also sample volume was 500 ml, except for Mn (87% recovery). The sorption capacity of the resin was found to be 0.77, 0.41, 0.57, and 0.30 mg g(-1) for Cu(II), Ni(II), Cd(II), and Mn(II), respectively. The preconcentration factor of the method was 200 for Cu(II), 150 for Pb(II), 100 for Cd(II) and Ni(II), and 50 for Mn(II). The recovery values for all of the metal ions were > or = 95% and relative standard deviations (RSDs) were < or = 5.1%. The detection limit values were in the range of 0.03 and 1.19 microg l(-1). The accuracy of the method was confirmed by analysing the certified reference materials (TMDA 54.4 fortified lake water and GBW 07605 tea samples) and the recovery studies. This procedure was applied to the determination of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) in waste water and lake water samples.