Presentation is loading. Please wait.

Presentation is loading. Please wait.

Air, Water and Land Pollution Chapter 4: Environmental Sampling Techniques Copyright © 2010 by DBS.

Similar presentations


Presentation on theme: "Air, Water and Land Pollution Chapter 4: Environmental Sampling Techniques Copyright © 2010 by DBS."— Presentation transcript:

1 Air, Water and Land Pollution Chapter 4: Environmental Sampling Techniques Copyright © 2010 by DBS

2 Contents General Guidelines of Environmental Sampling Techniques Techniques for Sampling Various Media: Practical Approaches and Tips

3 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sequence of Sampling Matrices and Analytes Project deals with multimedia and/or multiple parameters use following sequence: –Collect from least to most contaminated sampling locations –If sediment and water is being collected, collect water first to minimize effects from suspended bed materials –For shallow streams, start downstream and work upstream to minimize sediment effects due to sampling disturbances –If sampling at different depths, collect surface samples first and then proceed deeper –Always collect VOCs first, followed by SVOCs (e.g. pesticides, PCBs, oil, etc.), then total metals, dissolved metals, microbiological samples, and inorganic nonmetals

4 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Amount Minimum sample required depends on the concentration of the analytes present Should take enough for all analyses and additional for any QA/QC work required Heterogeneous samples generally require larger amounts to be representative of sample variations Taking too much sample can lead to problems with storage and transportation

5 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Amount - Water 5 mL for total petroleum hydrocarbons (TPHs), 100 mL for metals, 1 L for trace organics (pesticides) As a general rule the minimum volume collected should be 3-4 times the amount required for analysis (EPA, 1995)

6 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Amount – Soil/Sediment/Solid Waste For physiochemical properties (particle size, texture etc.) requires a minimum of 200 g soil For contaminant analysis g is sufficient More samples are required if the goal is to detect low solubility (hydrophobic) organic contaminants Sample volume of waste samples should be kept small to reduce disposal costs

7 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Amount – Air Samples Volume of air required depends on the minimum chemical concentration that can be detected and the sensitivity of the measurement Concentration range may be unknown – sample size determined by trial and error

8 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Amount – Water/Sediment Samples for Toxicity Testing L Water for an effluent toxicity test 15 L sediment for bioaccumulation tests 8-16 L sediment for benthic macroinvertebrate assessments (EPA, 2001)

9 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Preservation and Storage Purpose – minimize physical, chemical and biological changes 3 approaches: –Refrigeration –Use of proper sample container –Addition of preserving chemicals

10 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Preservation and Storage Refrigeration is a universally accepted method to slow down loss processes Container choice (material type and headspace) is critical to reduce –Volatilization –Adsorption –Absorption –Diffusion –Photodegradation Addition of preservatives is critical to reduce losses due to chemical reactions and bacterial degradation

11 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Preservation and Storage

12 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Preservation and Storage Maximum Holding Time (MHT) is the length of time a sample can be stored after collection and prior to analysis MHTs vary by agency

13 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Preservation and Storage American Public Health Association (APHA) MHTs:

14 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Sample Preservation and Storage Immediate: pH, temperature, salinity, DO Within 1-2 days: careful pre-planning is required to avoid sampling on Friday, Saturday or near holidays

15 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sample Containers Water Glass vs. Plastics: –Glass may leach boron and silica, metals may stick to walls –Glass is generally used for organics and plastic for metals, inorganics and physical properties –For trace organics cap and liner should be made of inert materials (teflon) Headspace vs. no Headspace: –No headspace is allowed for VOC samples –40 mL vial with a teflon-lined septum –Oil and grease should only be half-filled in wide mouthed glass bottles Special containers: –e.g. BOD/DO bottles and VOC vials

16 1-33 Standard Methods (1998)

17 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sample Containers Soil Low temperature storage No preservatives except ethanol or sodium bisulfite for VOC analysis (Popek, 2003) Biological Aluminum foil (shiny side out) and closed glass containers with inert seals or cap liners

18 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sample Containers Air Various collection media: –Filter cassettes –Adsorbent tubes –Bags –Canisters Reeve, 2002

19 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Surface Water and Wastewater Sampling Grab sampler, weighted bottle sampler, Kemmerer bottle

20 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Groundwater Sampling Collected from wells using a bailer or by pumps (peristaltic and bladder) Samples do not come into contact with mechanical components of the pump

21 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Soil Sampling Soil depth and whether or not each soil horizon is necessary to sample are main considerations Scoops and trowels, tube sampler, augers, split spoon sampler (drilling)

22 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Sediment Sampling Dredges (Ekman dredge, Peterson dredge, Ponar dredge) Core samplers (Livingstone, Kullenberg, and Mackereth)

23 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Sediment Sampling Dredges (Ekman dredge, Peterson dredge, Ponar dredge) Core samplers (Livingstone, Kullenberg, and Mackereth) Glew et al, 2001

24 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Hazardous Waste Sludges: Dredges, scoops, trowels, buckets Composite liquid waste: coliwasa, Thief and Trier samplers

25 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Biological Sampling Very unique and diverse range of equipment –Mammals - Trapping(live and kill) –Fish - Electrofishing, gill nets, trawl nets, sein nets, minnow traps –Benthic macroinvertebrates - Petersen and Ekman dredges

26 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Air Sampling Many direct-reading instruments for monitoring (real-time) levels Sampling still needed for trace level analysis (expensive and complex) e.g. High volume total suspended particulate samplers (TSP), PM-10 samplers, PM- 2.5 samplers, personal sampling pumps, canister samplers

27 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Air Sampling TSP/PM-10

28 Question Calculate the PM-10 concentration for the following conditions: Filter mass gain = mg Sample time = 1446 min Initial sampler flow rate = cm 3 min -1 Final sampler flow rate = cm 3 min -1 Average flow rate = cm/min Volume of air = cm 3 /min x 1446 min = 2662 cm 3 = x10 -3 m 3 PM concentration = 6.70 x μg / x m 3 = μg m -3

29 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Air Sampling Summa canister, filter cassettes (particulates), impingers, diffusion tubes, sorbent tubes, polyurethane foam (PUF)

30 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Air Sampling SUMMA canister –Electroplated with Ni and Cr oxides to prevent adsorption of VOCs –Low-ultra low ppt-ppb range concentrations

31 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Air Sampling Palmes diffusion tubes (PDTs)

32 Environmental Sampling Techniques General Guidelines of Environmental Sampling Techniques Selection of Sampling Equipment Air Sampling Polyurethane Foam Sampler (PUF) For organics need both solid and vapor phases Vapor cartridge is placed in-line with quartz fiber filter for semi-volatile organics –PUF plug –Adsorbent resin (XAD-2) - Pesticides - PCB’s - Dioxins - PAH’s

33

34 Environmental Sampling Techniques Techniques for Sampling Surface Water and Wastewater Sampling Fresh surface waters: flowing waters, static waters and estuaries Wastewaters: mine drainage, landfill leachate, industrial effluents etc. Differ in their characteristics, samples collection is specific for each

35 Environmental Sampling Techniques Techniques for Sampling Surface Water and Wastewater Sampling Streams and rivers – size and amount of turbulence impact representativeness of samples –Small streams (<20 ft wide) possible to select a location where a grab sample represents the entire cross-section –Larger streams and rivers multiple samples across the channel width are required (Also at least one vertical composite (surface, middle, bottom)) –Fast moving rivers and streams difficult to collect mid-channel sample –Ponds and impoundments use a single vertical composite at deepest point –Estuaries inland fresh water mixes with oceanic saline water have specific sampling routines

36 Environmental Sampling Techniques Techniques for Sampling Groundwater Sampling Requires installation of a sampling well Well must not change integrity of surrounding waters Routine groundwater sampling tasks: –Characterize flow –Purge and stabilize groundwater prior to sampling –Minimize cross-contamination due to well materials and sampling devices

37 Environmental Sampling Techniques Techniques for Sampling Groundwater Sampling Groundwater Flow Direction Hydraulic gradient – slope of water table measured from high point to low point across a site Flow is proportional to gradient, in direction of gradient Hydraulic head is a vertical measurement from sea level to the water table Hydraulic gradient = Difference in Hydraulic Head/Distance between two wells

38 Environmental Sampling Techniques Techniques for Sampling Groundwater Sampling Well Purging Used to remove stagnant water in the well borehole and sandpack for representative sample USGS stabilization parameters: –DO ± 0.3 mg/L –Turbidity ± 10 % (for samples > 10 NTUs) –Specific conductivity ± 3% –ORP ± 10 mV –pH ± 0.1 unit –Temp. ± 0.1 o C

39 Environmental Sampling Techniques Techniques for Sampling Groundwater Sampling Cross Contamination

40 Environmental Sampling Techniques Techniques for Sampling Soil and Sediment Sampling Soil sampling at shallow depths relatively easy Sediments are treated similarly with regard to post-sampling pretreatment (homogenizing, splitting, drying and sieving) Horizontal (grab) or vertical (core) sampling Composite sampling is common (except for VOCs) Nonsoil/sediment or nonsieved materials should be noted and not discarded Sediments from lakes, ponds and reservoirs should be collected at the deepest point (contaminants tend to concentrate in fine grained material in depositional zones)

41 Environmental Sampling Techniques Techniques for Sampling Hazardous Waste Sampling Sources: drums, storage tanks, lab packs, impoundments, waste piles, debris Sampling approach varies considerably Requires HAZWOPER training Drums etc. Research documentation (labels etc.) for health and safety precautions Use proper protective equipment Unknown wastes should be opened remotely Should not be moved since some chemicals are shock-sensitive, explosive or reactive Sample each phase separately

42 Environmental Sampling Techniques Techniques for Sampling Hazardous Waste Sampling Waste Impoundments Contaminants will be stratified by depth, also horizontally from point of entry Surface Sampling Wipe, chip and dust sampling

43 Environmental Sampling Techniques Techniques for Sampling Biological Sampling Biological samples difficult to collect Species availability - Insufficient sample size may result in invalid statistical inference Sampling protocol needs to account for size differences between species, tissue differentiations, growth stage, and habitat Susceptible to decomposition of organic analytes

44 Environmental Sampling Techniques Techniques for Sampling Air and Stack Emission Sampling Ambient air, indoor workplace air and stack/emission exhausts Concentrations for most atmospheric pollutants are very low Analysis of organic compounds requires huge volumes Large variation in analyte concentration due to changes in meteorlogy Meteorological parameters must be noted

45 Environmental Sampling Techniques Techniques for Sampling Air and Stack Emission Sampling Indoor Air Ventilation systems can alter air flow and add pollutants Sampler location will influence the results obtained Household chemicals can add compounds to the air

46 Environmental Sampling Techniques Techniques for Sampling Example 4.1: Two wells are drilled 300 m apart along an east-west direction. The east well and west well have hydraulic heads of 20.4 m and 20.0 m, respectively. The third well is located 200 m due south of the east well and has a head of 20.2 m. Schematically determine groundwater flow and direction and estimate hydraulic gradient. Hydraulic Gradient = Head of well C – Head of well B/Distance from B to the equipotential line CD = (20.2 – 20.0) / 120 =

47

48 References Bodger, K. (2003) Fundamentals of Environmental Sampling, Government Institutes, Rockville, MD. Cowgillum (1988) Sampling Waters: The Impact of sample variability on planning and confidence Levels, In: Keith, L.H. (1988) Principles of Environmental Sampling. American Chemical Society, Washington, DC. US EPA (1995) Superfund Program Representative Sampling Guidance: Volume 2, Air (Short-Term Monitoring), Interim Final, EPA 540-R , OSWER Directive , PB , December US EPA (2001) Methods for Collection, Storage and Manipulation of Sediments for Chemical and Toxicological Analyses: Technical Manual. EPA-823-B , October Keith, L.H. (1988) Principles of Environmental Sampling. American Chemical Society, Washington, DC. Keith, L.H. (1991) Environmental Sampling and Analysis: A Practical Guide. Lewis Publishers, Boca Raton, Fl. Reeve, R.N. (2002) Introduction to Environmental Analysis. Wiley. Popek, E.P. (2003) Sampling and Analysis of Environmental Chemical Pollutants: A Complete Guide. Academic Press, San Diego, CA.

49 Questions 2. Which of the following should be monitored in the field: (a) acidity, (b) DO, (c) pesticide, or (d) hardness. 5. Explain why: (a) HNO 3 rather than other acids is used for metal preservation; (b) amber bottles are preferred for PAHs; (c) zero-head space container for groundwater samples collected for tetrachloromethylene analysis. 8. Explain why glass containers are generally used for organic compounds whereas PVC- type containers are used for inorganic compounds. 11. The maximum holding time for metal analysis (excluding Cr 6+ and dissolved Hg) after acidification to pH < 2 is most likely: (a) 6 h, (b) 6 days, (c) 6 weeks, (d) 6 months. 18. Suppose you were recently hired as an entry level Environmental Field specialist in a new firm dealing with groundwater remediation where a sampling and analysis plan (SAP) has not been developed. You are assigned as an assistant to a Project Manager for groundwater sampling, and are asked to do the office preparation for this sampling event. Make a list of items you may need in the field. Exclude containers and sampling tools in the list.


Download ppt "Air, Water and Land Pollution Chapter 4: Environmental Sampling Techniques Copyright © 2010 by DBS."

Similar presentations


Ads by Google