MEASUREMENT SCIENCES IN DRINKING WATER QUALITY MONITORING

Transcription

1 MEASUREMENT SCIENCES IN DRINKING WATER QUALITY MONITORING Dr. Lifeng ZHANG Water Quality Office, PUB

2 Outline of presentation Background Guidelines for Drinking-water Quality Measurement Methods: a) Regulated Pollutants; b) Contaminants of Emerging Concern in Water Bodies Future Prospects

3 Background Pollutants in Aquatic Environment Organic water pollutants include: Detergents Disinfection by-products found in chemically disinfected drinking water, such as chloroform Food processing waste, which can include oxygen-demanding substances, fats and grease Insecticides and herbicides, a huge range of organohalides and other chemical compounds Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and lubricants (motor oil), and fuel combustion byproducts, from stormwater runoff Volatile organic compounds (VOCs), such as industrial solvents, from improper storage. Various chemical compounds found in personal hygiene and cosmetic products Heavy Metals

4 Background Pollutants in Aquatic Environment pollutants are present in the effluents of wastewater treatment plants, the receiving surface water, and even ground waters. concern regarding the occurrence and effects of pollutants in water system has been growing. BP oil spill: Deepwater Horizon oil spill (also referred to as the BP oil spill, the BP oil disaster, the Gulf of Mexico oil spill) A garbage collection boom in an urban-area stream. A manhole cover unable to contain a sanitary sewer overflow.

5 Background Risks for Ecosystems Acute Toxicity Most information on ecotoxicological effects of pollutants is available from acute toxicity data. Over 9% of the acute toxicity studies have an effect concentration mg/l. Bacteria, cyanobacteria and algae can be relatively sensitive to antibiotics. Chronic Toxicity Chronic toxicity data are mainly from reproduction tests with Daphnids, or growth inhibition tests with algae or cyanobacteria. Chronic effect concentrations are at the level of a few tens of μg/l. 5

6 Background Risks for Ecosystems Specific Toxicity There are unknown effects on metabolic systems of nontarget organisms, especially invertebrates. For example, recent evidence shows that pharmaceuticals with highly specific mechanisms can elicit profound effects at extremely low concentration. These effects are not necessarily readily detectable but have the potential to lead to ecologic change that could be erroneously attributed to natural changes. Development of Resistance Especially for antibiotics 6

7 Background Risks for Ecosystems Fish around the world have been reported dead in PCBcontaminated waters. 7

8 Background Human Health Risk Possible effects of long-term exposure to pollutants are: Endocrine disrupting; Induction of antibiotic resistance; Genotoxicity; Carcinogenicity; Allergic reactions. 8

9 Guidelines for Drinking water Quality Organizations for formulating guidelines for drinking-water quality: WHO-World Health Organization USEPA-(Environmental Protection Agency) EU-The Council of the European Union 9

10 Guidelines for Drinking water Quality WHO-World Health Organization One of the main roles: to establish international norms to protect human health. Since 958, WHO has published at around ten-year intervals several editions of International Standards for Drinking-water and subsequently, the Guidelines for Drinking-water Quality. The Guidelines for Drinking-water Quality: Provide an evidence-based point of departure for standard setting and regulation as a basis for health protection; Include an assessment of the health risks presented by the various microbial, chemical, radiological and physical constituents that may be present in drinking-water. Where applicable, they derive maximum concentration guideline values for these hazardous constituents.

11 Guidelines for Drinking water Quality WHO's role in drinking-water safety: guidelines, not standards? In 98, WHO shifted its focus from International Standards to Guidelines. The main reason for the shift is the advantage provided by the use of a risk-benefit approach (quantitative or qualitative) to the establishment of national standards and regulations. Specifically, the application of the Guidelines to different countries should take account of the sociocultural, environmental and economic circumstances particular to those countries.

12 Guidelines for Drinking water Quality

13 Guidelines for Drinking water Quality Guideline values for individual chemicals, by source category

14 Guidelines for Drinking water Quality

15 Guidelines for Drinking water Quality 5

16 Guidelines for Drinking water Quality 6

17 USEPA Standards for Drinking water Quality USEPA 7

18 USEPA Standards for Drinking water Quality 8

19 Guidelines for Drinking water Quality 9

20 Guidelines for Drinking water Quality

21 Guidelines for Drinking water Quality EU-The Council of the European Union

22 Guidelines for Drinking water Quality ENVIRONMENTAL PUBLIC HEALTH REGULATIONS 8Singapore

23 Guidelines for Drinking water Quality Analytical Methods for Organic Chemicals

24 Guidelines for Drinking water Quality

25 Guidelines for Drinking water Quality 5

26 Guidelines for Drinking water Quality 6

27 Analytical Methods Procedure for Organic Compounds Analysis in Water Sample Step : Collect water samples and store at ºC Step : Sample preparation Step : Instrument analysis 7

28 Analytical Methods Sampling 8

29 Analytical Methods Sample Preparation Techniques To analyze the organic pollutants in aquatic enviromental samples with complex matrices, sample preparation is a primary step. Several goals of sample extraction: Separate the target organic compounds from a complex aqueous matrix such as sewage and marine water samples to remove the interference and matric effects. Enrich target analytes in trace level and improve determination sensitivity. Consider the compatibility between the sample matrix and the instrumental analysis. For example, generally aqueous samples are not immediately analyzed with gas chromatographic analysis in which a solvent extraction procedure is normally applied. 9

30 Analytical Methods Sample Preparation Techniques Sample preparation includes liquid-liquid extraction, solid-phase extraction, solid-phase microextraction, stir-bar sorptive extarction, liquid-phase microextraction, etc. Liquid-liquid Extraxction a traditional technique based on the partition of the dissolved analytes between the organic solvent and the aqueous sample according to their partition coefficients tedious operation procedure and large amount of organic solvent consumed

31 Analytical Methods Sample Preparation Techniques Solid-phase Extraxction a more modern extraction technique and the most common sample preparation technique in environmental analysis. based on the sorption of analytes on the sorbent: In this procedure, organic compounds are initially trapped on the sorbent while the aqueous sample is passed through the cartridge or disk. Then the target compounds are eluted with a suitable solvent. SPE Procedures

32 Analytical Methods Sample Preparation Techniques Solid-phase Extraxction Advantages : higher recoveries; improved selectivity, specificity and reproducibility; elimination of emulsions; less organic solvent usage; shorter sample preparation time; easier operation and the possibility of automation (for example: SPE workstation, on-line solid-phase extraction). SPE Cartridges SPE Workstation

33 Analytical Methods Sample Preparation Techniques Solid-phase Microextraxction (SPME) a modern equilibrium extraction method; a fused silica fiber coated with a polymeric phase; three modes of operation: direct immersion extraction; headspace extraction; less commonly-used membraneprotected SPME Advantages: completely eliminating the usage of organic solvents; a simple operation procedure; Limitations: short fiber lifetime, high cost, fragility, carry-over effects and lacking selectivity when extracting analytes in complex matrices Direct Immersion SPME

34 Analytical Methods Advanced Instruments Chromatography, including gas chromatography (GC) and high performance liquid chromatography (HPLC), is the dominant modern analytical technique. Gas Chromatography (GC): used to separate volatile components of a mixture; inert gas such as helium and nitrogen, etc, used as mobile phase. Detectors: mass selective detector (MSD), electron capture detector (ECD), flame ionization detector (FID), nitrogen phosphorus detector (NPD), flame-photometric detector (FPD), etc. Agilent GC-MS instrument More advanced detectors: high-resolution MSD; triple quadrupole (QqQ) MSD;

35 Analytical Methods Gas Chromatography (GC): Purge and Trap GC-MS one of the most commonly used techniques employed by environmental testing laboratories used for the analysis of volatile analytes, such as purgeable aromatics, ketones, trihalomethanes, and other halocarbons from environmental water, solid, waste, and air samples. Purge and trap GC-MS instrument Purge and trap GC-MS structure 5

36 Analytical Methods Derivatization Improve chromatographic performance Improve the detection Improve the thermo-stability ) Detection of HAAs ClCHCOOH + MeOH (HSO) ClCHCOOMe ) Detection of aldehyde: HCHO, CHCHO, etc Detection by GC-ECD after MLLE ) Detection of Phenols Detection by HPLC after LLE Detection by SPME GC-MS Detection by GC-MS 6

37 EM-6 GC-MS Analytical Methods Gas Chromatography (GC): Portable GC-MS HAPSITE instrument several portable GC-MS systems in the market HAPSITE is the person-portable GC-MS. Qualitative and quantitative results in the field can be delivered in less than minutes. Target compounds include volatile organic compounds (VOCs), toxic industrial chemicals (TICs), toxic industrial materials (TIMs), chemical warfare agents (CWAs), and selected semi-volatile organic compounds (Inficon application note-a, 9). Both CT-8 GC-MS and EM-6 GC-MS are mobile GC-MS system designed for the fast and simple on-site assessment of chemical catastrophes and accidents as well as other environmental problems involving organic chemicals. CT-8 GC-MS EM-6 GC-MS 7

38 Analytical Methods Gas Chromatography (GC): On-line GC-MS Usually for VOCs Currently, most of on-line GC-MS was based on modified purge and trap technique and the choice of it is limited in the market. Online Sampler for Purge & Trap Designed for applications where a single water stream needs to be measured automatically and repeatedly by purge & trap. Automatically fills and empties the test tube purge vessel. CMS5 Monitoring System Structure of online GC-MS Introduced by INFICON for continuous, unattended remote monitoring of water or air Analyzing and quantifying VOCs and TICs on-site accurately in minutes using GC technology, thus providing the answers needed to make fast decisions about potentially critical issues. Micro Argon Ionization Detector used for easy operation and maintenance 8

39 Analytical Methods High performance liquid chromatography (HPLC): used to separate polar, non-volatile components of a mixture; aqueous phase used as mobile phase. Detectors: mass selective detector (MSD), UV detector, fluorescence detector, electrochemical detector, conductivity detector, refractive index detector, evaporative light scattering detector, etc. More Advanced Detectors: time of flight MS (TOFMS); hybrid quadrupole-time of flight mass spectrometer (QqToF); LC-MS/MS Instrument HPLC structure 9

40 Analytical Methods Analysis Trends Chromatography Trends - Ultroaperformance liquid chromatography (UPLC) introduced and emplyed to dramatically shorten analysis times, often to min or less. - Two-dimensional GC (GC X GC) used for screening contaminants - Hydrophilic interction chromatography (HILIC) employed to sepearte highly polar compounds such as haloacetic acids in drinking water and melamine-cyanuric acid complexes - Further chromatographic separation: chiral separation Waters UPLC system Waters UPLC column Packing Materials

41 Analytical Methods Analysis Trends Detection Trends Many advanced instruments including TOF- and quadrupole (Q)-TOF-MS have been used to provide exact mass data and identify transformation products of emerging contaminants. Online Analysis Online SPE coupled to LC/MS/MS is being increasingly used because of its high sensitivity and selectivity, minimum sample preparation, more reproducibility, and automation. Detection Limits Lower detection limits as low ng/l or even pg/l have been obtained with new analytical methods.

42 Online SPE-LC-MS/MS

43 Online SPE-LC-MS/MS-- Caffeine present in several beverages, including coffee, tea, soft drinks, and in many pharmaceuticals levels of caffeine in domestic wastewater have been measured to be between and µg/l

44 Online SPE-LC-MS/MS-- Caffeine Acq. File: -online SPE-for marina sample.wiff Sample Name: std-ppt- Sample Number: N/A XIC of +MRM (6 pairs): 95./8. Da from Sample (std-ppt-) of -online SPE-for marina sample.wiff (Turbo Spra... Max. 7.e cps.. 7.e 7.e 6.5e On-line SPE cartridge: Strata-X (. mm, 5 μm) Oasis HLB (. mm, μm) LC column: Kinetex.6 μm C8,.6 mm) Mobile phase and gradient program: A:.% FA in HO; B: ACN 6.e 5.5e caffeine In te n s ity, c p s 5.e.5e.e.5e.e.5e.e.5e.e Time, min Water sample: ph Loading flow rate: ml/min Time (min) A% B%

45 Online SPE-LC-MS/MS Analytes Caffeine Bisphenol A Paracetamol Compound MDL (ng/l) PQL (ng/l) Linearity (ng/l) MDL (ng/l) PQL (ng/l) Sulfamethoxazole..5 Sulfadiazine Sulfamerazine Ofloxacin Ciprofloxacin Enrofloxacin 8..5 Norfloxacin.9.8 Danofloxacin.8 7. Lincomycin On-line SPE can reduce contamination, normally caused by the release of Bisphenol A from the cartridge used in the off-line SPE, thus improve method accuracy. 5

46 Isotope Dilution Quantitation Isotope Dilution Quantitation A method of determining a compound by reference to the same compound in which one or more atom has been isotopically enriched. In this method, labeled are enriched with deuterium to produce H labeled analogs or carbon- to produce C-labeled analogs. Why? Signal drift in chromatography; Matrix effects in ionization of mass spectrometer; Losses of substance or matrix effects during sample preparation; ---- the isotope analogs have almost exactly the same chemical properties as native compounds, thus have the almost same chromatography character and ionization pattern, then can allow identification and correction of the concentration of the native compounds in the analytical process. In a gas chromatography analysis, the error from injection can be approximately 5% Example: By adding an internal standard, the error can be reduced by half to approximately -% With isotope dilution, the error should be half of that again, approximately % 6

47 Isotope Dilution Quantitation Addition of known mass of isotope labeled analogs to known water samples Tests and corrections for blanks and interferences Isolation of native compounds and labeled analogs from water samples Further separation from potential interferences Precise isotope ratio measurements of the labeled and unlabeled forms Calibration of the native compounds with labeled analogs (in known mixtures) using the relative response (labeled to target): RR=AnC/ACn Calculate results An = the area of m/z for the native compound A = the area of m/z for the labeled compound C = the concentration of the labeled compound in the calibration standard Cn = the concentration of the native compound in the calibration standard 7

48 Isotope Dilution Quantitation Application EPA Method 69: Pharmaceuticals and Personal Care Products in Water, Soil, Sediment, and Biosolids by HPLC/MS/MS EPA Method 6: High Resolution GC/MS Method for the Determination of Tetra-Octa Chlorinated Dioxins and Furans 8

49 Disinfection By-products (DBPs) DBPs are formed by reactions between natural organic and inorganic matters in water with disinfectants such as chlorine, ozone, chloramine, and chlorine dioxide etc. during water disinfection process. 9

50 Disinfection By-products (DBPs) Tekmar Purge-and-Trap coupled to Agilent GC/MS for THMs analysis. Gas chromatography and mass spectrum 5

51 Cyanotoxins Cylindrospermopsins Lipopolysaccharides Cytotoxic Hepatotoxic Irritant toxins Neurotoxic Nodularins, Microcystins Anatoxins, Saxitoxin Cyanotoxins 5

52 Cyanotoxins Biological Assay ELISA Chromatographic LCMS/MS TOFMS/MS New Study: fast, portable and real time monitoring Biosensor Single-walled carbon nanotubes (SWNTs) 5

53 Off-flavor Compounds Surface water supplies are more likely to be affected by substances causing undesirable tastes and odors, the largest single class of consumer complaints submitted to water utilities. Objectionable taste and odor in tap water will compromise public confidence in the water quality 5

54 Off-flavor Compounds Taste and Odor Wheel (Suffet et al. 999) 5

55 Off-flavor Compounds Flavor Profile Analysis (FPA) FPA is a technique for identifying sample odou(s). FPA Analysis Laboratory FPA Analysis Work Sheet FPA Analysis Results 55

56 Off-flavor Compounds Off-flavor Compounds Analysis Threshold Odor Test To determine the threshold odor by diluting a sample with odor-free water until the least definitely perceptible odor. Expressed by threshold odor numbers (TON) corresponding to various dilution GC-MS/Olfactometry Analysis GC-MS/Olfactometry instrument and analysis Olfactogram of a water sample 56

57 Treatment of Off-flavor Compounds Dil x Dil x OZONATION Dil x Dil 6x Dil 6x Inlet Stripping Maybe UV Ozonated REVERSE OSMOSIS Fluence 5 Inlet Fluence Maybe Good AERATION Fluence UV peroxide OZONATION DILUTION Feed Permeate Maybe C*T C*T Inlet Inlet Pre-O & BAC Good Good no-o & BAC Maybe Environmental Science &Technology,, (), CHLORAMINATION C*T Fluence BIOLOGICAL A.C. CHLORINATION Fluence Fluence 5 O & BAC Limited Limited C*T C*T C*T Poor 57

58 Contaminants of Emerging Concern Contaminants of Emerging Concern belonging to pollutants, have long been present in the environment but gained scientific or public attention until recently. including: - PFOA, PFOS and other perfluorinated compounds - Pharmaceuticals, hormones, and endocrine disrupting compounds - Drinking Water disinfection byproducts - Sunscreens/UV filters - Brominated flame retardants - Benzotriazoles - Dioxane - Naphthenic Acids - Pesticide degradation products and new pesticides - Perchlorate - Gasoline additives: MTBE and EDB - Algal Toxins - Arsenic - Microorganisms - Nanomaterials and other contaminants on the horizon 58

59 Pharmaceuticals, Personal Care Products and Endocrine Disrupting Compounds Paracetamol Pharmaceutic als introduced into water systems by humans as well as through veterinary use for livestock, poultry, and fishing farming Personal Care Products enter the wastewater mainly via wash-off during showing or bathing Endocrine Disrupting Compounds reach the aquatic environment through wastewater discharges 59

60 Contaminants of Emerging Concerns Pharmaceuticals and Personal Care Products (PPCPs) and endocrine disrupting compounds (EDCs) LC/MS/MS with electro-spray ionization at positive/negative mode is an efficient technique in the determination of PPCPs/EDCs in surface water. At multiple reaction monitoring mode, LC-MS-MS shown high sensitivity and sample matrix- minimizing effect in the detection of PPCPs/EDCs. Solid phase extraction conducted through Autotrace SPE Workstation and with a -fold pre-concentration, the MDLs for all PPCPs/EDCs are as low as ng/l. GC-MS combined with derivatization HPLC-MS-MS LC-QTOF LC-Orbitrap Detection of chemical compounds via Triple Quadrupole MS 6

61 Contaminants of Emerging Concern 6

62 Contaminants of Emerging Concern 6

63 Future Perspective Development of analytical methods with good sensitivity, reliability and reproducibility are always required to meet the new needs; The identification and analysis of unknown compounds in aquatic system is still a challenges, especially to those known-unknown or unknown-unknown organic compounds; Mass spectrometers acquiring full scan mass spectra at high resolution will gain more applications; More isotopically labeled standards (deuterated or C-labeled) will be applied to achieve more accurate quantification in a variety of sample matrixes; Fast detection system with field testing capability is required for rapid response; Real time monitoring is useful in assessment of the water quality of aquatic system and water treatment plant. 6

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