Manual of ohio epa surveillance methods

Risk characterization shall integrate the exposure and toxicity assessments in order to quantitatively determine the risk or hazard posed by the COCs on or from the property.

The risk characterization shall evaluate carcinogenic risks and non-carcinogenic hazard separately. The volunteer shall estimate cancer risks as an incremental probability of an individual member of a receptor population developing cancer over a lifetime as a result of exposure to carcinogenic COCs on or from the property; hereafter, this estimation of cancer risk is referred to as incremental cancer risk.

The volunteer shall calculate separately an incremental cancer risk, at a minimum, for each receptor population identified in accordance with the procedures described in paragraph D 3 b i of this rule. An estimate of incremental cancer risk for each receptor population shall not exceed the applicable carcinogenic risk goal in paragraph B 1 of this rule. An estimate of incremental cancer risk is calculated as follows:. The volunteer shall calculate a hazard index value to determine the exposure which is not likely to cause noncancer adverse health effects posed by COCs to each receptor population at a property for the duration of that exposure in accordance with the applicable noncancer hazard goals described in paragraph B 2 of this rule.

The volunteer shall calculate a separate hazard index for each receptor population over a specified exposure period i. The volunteer shall submit a written justification for separate hazard index calculations in the property-specific risk assessment report. The volunteer shall evaluate uncertainty associated with the property-specific risk assessment. The uncertainty analysis shall include a qualitative description or quantitative evaluation of uncertainty associated with any of the following:.

Further assessment is not needed if concentrations of COCs in sediment or surface water do not exceed the following:. The biological survey shall include the following:.

To accomplish this, the volunteer shall follow the procedures in "Biological Criterial for the Protection of Aquatic Life" hereinafter in this rule referred to as the "biocriteria manual" and Ohio EPA's division of surface water "Manual of Ohio EPA Surveillance Methods and Quality Assurance Practices," as both documents are incorporated by reference in rule of the Administrative Code.

If possible, the sampling locations for the fish and physical habitat survey shall include the same locations where sediment samples are collected. To accomplish this, the volunteer shall follow the biocriteria manual unless the water body does not have sufficient depth and flow to conduct a quantitative macroinvertebrate study.

If the water body does not have sufficient depth and flow to conduct a quantitative macroinvertebrate study, the volunteer shall conduct a qualitative macroinvertebrate study using the biocriteria manual and the instruction provided by the biocriteria certification and qualified data collector approval obtained in accordance with paragraph D of rule and paragraph B of rule of the Administrative Code.

If possible, the sampling locations for the quantitative macroinvertebrate survey shall include the same locations established where sediment samples are collected. The volunteer shall determine sediment bioassay sampling locations in accordance with this rule and rule of the Administrative Code. At a minimum, sediment bioassays shall include the ten-day survival and growth test for Hyalella azteca and Chironomus tentans following the procedures in U. Chironomus riparius may be substituted for Chironomus tentans if necessary.

The volunteer shall consult Ohio EPA for assistance to make a determination on an aquatic life use designation for an unlisted water body. Examples of such standards include, but are not limited to, the general water quality criteria, water use designations and statewide water quality criteria, the criteria provided for the applicable drainage basin, the site-specific modifications to criteria and values, and the methodologies for the development of criteria and values.

Applicable standards for sediment are met if the volunteer demonstrates that hazardous substances or petroleum on or from the property are not contributing to the failure to meet the applicable standards in paragraph F 5 of this rule. If sediment bioassay or biosurvey does not demonstrate full compliance with applicable standards, the volunteer shall conduct sediment sampling according to rule of the Administrative Code in order to determine the concentrations of COCs in sediments.

Prior to the inclusion of historical data within an applicable standards demonstration, volunteers shall consider any changes in the watershed, release history, property characteristics, or knowledge of recent data collection. G Surface water assessment. If concentrations of COCs in surface water exceed applicable standards in accordance with paragraph F 2 a of rule of the Administrative Code, then the standards for surface water in paragraphs E and F 5 of this rule are applicable.

H Determination of applicable standards from a property-specific risk assessment. If the volunteer elects or is required to apply risk derived standards determined in accordance with this rule, applicable standards from a property-specific risk assessment are one or more of the following:. The volunteer shall use the following equation, along with property-specific information, to calculate a property-specific soil saturation concentration:.

I Risk assessment information. Upon completion of a property-specific risk assessment conducted in accordance with this rule, the volunteer shall present the information in a risk assessment report or in a section of the phase II property assessment. Pour into sterile petri dishes. Warning: A longer period of sterilization will reduce the selectivity of the medium.

Prior to sterilization, add 1. Do not overheat and do not autoclave. Do not autoclave or over- heat. Twirl the flask prior to pouring plates to evenly dispense the characteristic precipitate. Use the plated medium on the day prepared. Composition: Difco Dispense into screw-cap tubes and sterilize for 1 5 minutes at 1 1 8 C 1 2 Ibs. Slant tubes for a generous butt. Salmonella cultures produce large amounts of hydrogen sulfide and lysine decar- boxylase. Composition: Difco Beef Extract 3.

Dis- pense in 4 ml amounts in screw-cap tubes and sterilize for 12 minutes at C 15 Ibs. Cool to give a deep butt and short slant. Inoculated LIA slants must be incubated with loosened caps. Composition: Peptone 1. Dis- solve and filter-sterilize. Add 15 grams of agar to ml laboratory pure water and boil to dissolve.

Cool to C and add asepti- cally ml of filter-sterilized urea agar base. Mix and dispense in sterile tubes. Slant tubes to form a 2 cm butt and 3 cm slant and cool. Composition: A filter-sterilized 10X solu- tion of urea agar base, 10 ml volumes in tubes. Refrigerate to store. Preparation: Add 1. Sterilize for 1 5 minutes at C 1 5 Ibs. Cool the agar to C and aseptically add a 10 ml tube urea agar base concentrate. Mix agar and concentrate. Dis- pense aseptically into sterile tubes and slant.

Dispense in screw-cap tubes and sterilize in the autoclave for 15 minutes at C 15 Jbs. Slant and cool tubes. Described by Leifson and modified by Ewing, the medium is used in differentiation of Salmonella. Dispense into tubes and sterilize for 15 minutes at C 15 Ibs. Add 5 grams L-lysine, L-ornithine, L-arginine or other L-amino acids as desired per liter of medium and warm to dissolve completely. About 2.

Lysine or arginine do not require pH adjustment. Dispense in 5 ml volumes into screw-cap tubes and sterilize for 15 minutes at C 15 Ibs. The proper pH for the complete medium 6. Recommended for detection of motil- ity of gram-negative enteric bacilli. Dispense in tubes and sterilize for 15 minutes at C 15 Ibs.

To aid in recognizing motility, add 0. Composition: Beef Extract 3. After wetting powder, heat care- fully to boiling on a hot plate to dissolve com- pletely. Dispense 5 ml amounts In screw-cap test tubes.

Use: Isolation of actinomycetes from water or soil. Dissolve ingredients using gentle heat. Add the agar last and place in a boiling water bath.

Heat and stir occasionally until dissolved. Dispense ml volumes in ml screw-cap flasks and 17 ml volumes in screw-cap tubes. Laboratory Pure Water. Stills are dependable and long-lived if maintained and cleaned properly.

Use of sof- tened water as the source water increases the interval between cleanings of the still. Stills characteristically produce a good grade of water which gradually deteriorates as corro- sion, leaching and fouling set in.

There is no sudden loss of water quality unless a structural failure occurs. Stills are efficient in removing dissolved chemicals but not dissolved gases. Fresh laboratory pure water may contain chlo- rine and ammonia. On storage, ammonia will increase and CO2 will appear from air contami- nation. Distilled water systems should be monitored continuously for conductance and analyzed monthly for chlorine, ammonia and standard plate count and at least annually for trace metals.

See Table IV-A Amines may elute from the resin. Organic carbon results from organic chemicals in the water or from bacterial growth in the columns.

Use of a 0. Avoid the sudden loss of good quality water by continuously monitoring perfor- mance of the system, anticipating the remain- ing life of cartridges and replacing them be- fore failure occurs. The ideal dilution water is neutral in effect. It maintains bacterial populations without stimulating cell growth and reproduction, damaging cells or reducing their ability to sur- vive, grow or reproduce. Its basic purpose is to simulate the chemical conditions of the natural environment which are favorable to cell stability.

Microbiologists have tried different ap- proaches to obtain an ideal diluent Some workers have copied the natural environment by use of sterile fresh or marine waters as diluents, but these are non-standard. Other workers have used tap waters with the same lack of uniformity and an added potential for toxicity. Certainly for comparability of microbi- ological data the dilution water must be uni- form between laboratories. The chemical ele- ments and compounds required in natural con- ditions to insure a balance of cell solutes and maintain cell turgidity must be reproduced in the laboratory.

Inorganic constituents such as sodium, potassium, magnesium, phosphate, chloride and sulfate, and soluble organics such as pep- tone are used in synthetic dilution waters. Two standard dilution waters are: 7. Sterilize by filtration or autoclave for 15 minutes at C 15 Ibs. Handle aseptically. If evidence of mold or other contamination ap- pears, the stock solution should be discarded and a fresh solution prepared.

Loosen screw-caps on bottles and sterilize at C for 15 minutes 15 Ibs. Tighten screw- caps after sterilization and store in a cool place. Prepare dilution water for rinsing in iOO ml or larger volumes and autoclave for 30 minutes or more.

Bottles or flasks must be separated sufficiently in the autoclave to per- mit easy access for steam. Songer, J. Sullivan and J. Monroe, Safe, convenient pipetting device. Braymen and R. Mathis, Safe, convenient pipetting station. Taylor, R. Bordner and P.

Scarpino, Delayed incubation membrane-filter test for fecal coliforrns. Taylor, W. Isolation of Shigellae. Xylose lysine agars; new media for isolation of enteric pathogens. General Conditions Pertaining to the Cultivation of Microorganisms; and. Preparation of Media from Dehydrated Culture Media. Difco Manual. Difco Laboratories, Detroit, Ml. Baltimore Biological Laboratories. Handbook for Evaluating Water Laboratories 2nd Edition.

American Public Health Association, American Public Health Association, Inc. Although experienced microbiologists and technicians may not require the depth of information and the degree of detail given in this Section, it is provided to serve the technical personnel who are new to environmental microbiology.

The procedures included are: 1. Preparation for Analyses 2. Membrane Filtration Method 4. Most Probable Number Method 5. Staining Procedures 6. Preparation for Analyses 1. See Figures ll-C-1, 2 and 3. See Table V-C Keep a covered container of iodophor or quaternary ammonium disinfectant available for emergency use.

Phenolics are acceptable if analyses for these compounds are not per- formed as part of laboratory work. D«p»h Wa»«rT»mp. XVition Cdifwrn Pr«». LST 24Hra. CoKform Conf. BGLB 48 Hr.. Fical Cdlfortn EC 24Hrj. D MPN EC PER ML. Use only autoclavable pyrex glass, stainless steel or plastic blender containers with safety screw covers to prevent release of aerosols.

Use of a large blender container rather than smaller units also reduces heat, 1. Dry at C to constant weight. Add to a 99 ml volume of buffered dilu- tion water for a dilution and blend sample aseptically in a Waring-type blender at rpm for 30 seconds. Use only a pyrex glass, stainless steel or plastic blender container with safety screw lid to prevent release of aerosols. Repeat this process until the desired dilution is reached. This procedure is repeated until the desired bacterial density is reached.

After dilu- tion of the sample, the bacteria are enumer- ated using the membrane filtration, pour plate, streak plate, or the most probable number technique. For ease of calculation and preparation, serial dilutions are usually prepared in suc- ceeding ten-fold volumes called decimal dilu- tions. The decimal dilution procedure is shown in Figure ll-C The recommended method for obtaining counts within these limits is to filter dilution volumes of the decimal series which have a factor of 3, 4 or 5 among them see Table ll-C-1 for details.

Take care to secure the screw-cap and prevent leakage during shaking. Preparation of Decimal Dilution. Shake sample vigorously about 25 times and with- draw 1. For example, if 2. A dilution can be obtained by test- ing 2 ml of a dilution. Therefore, dilutions of samples should be tested as soon as possible after make-up and should be held no longerthan 30 minutes after preparation. Streak, Pour and Spread Plate Methods 2. These techniques described herein use solid or melted agar plating media to dilute out the microorganisms so that individual species or cells can be selected or counted from mixed cultures.

Because colonies can originate from more than one cell, results may be report- ed as colony-forming-units CPUs. The inoculum is progressively di- luted with each successive streak, and eventu- ally single cells are deposited on the agar surface. After suitable incubation, single iso- lated colonies develop in the path of the streak, see Figure ll-C After an appropriate series of dilutions, the original bacterial population is diluted out to a countable level, as described in 1.

Aliquots of the diluted sample are added to sterile petri dishes and mixed with melted agar. After the agar solidifies, the plates are inverted and incubated for a predetermined time.

Surface or subsurface colonies will de- velop in some of the agar plates. These colo- nies can be counted to provide a quantitative value for the bacterial density of the original sample, or they can be picked for further quali- tative study. The Inoculum is spread uniformly by holding the stick at a set angle on the agar and rotating the agar plate or rotating the stick until the Inoculum is distributed evenly.

The methods can isolate specific bacteria by the use of se- lective or differential media. The streak plate is only qualitative but the pour plate procedure can be used to quantitate bacteria present in a sample as in the Standard Plate Count Method see Part III-A , The spread plate method provides a quantitative method for aerobic surface growth of cultures against which other surface growth methods such as the MF technique can be compared.

Allow to harden and dry for bast results in streaking. Sterilize the needle by heating it to redness in a flame, and air-cool. Flame and cool needle after each step and inoculate plate further by drawing the needle across the area previously streaked. Streaking patterns other than the model shown in Figure ll-C-5 can be used; the objective is simply to deposit fewer and fewer cells along the streak until single cells are deposited on the agar surface.

After incubation, these cells will develop into well- separated pure colonies of bacteria, each theo- retically arising from a single bacterium. Moisture interferes with development of isolated colonies by spreading bacterial growth over the agar surface. Pick typical colonies using a sterile inoculating needle, suspend cells in dilution water, and restreak on an agar plate, repeating steps 2.

Isolated, single colonies from a plate containing like colonies may be considered to be pure. Dur- ing shaking, close cap tightly to prevent leak- age of sample and the danger of contamination.

One recommended technique uses a se- quence of five rotations to the left, five to the right and five forward and backward. Allow the agar to solidify on a level surface. After incuba- tion, well-isolated surface and subsurface colo- nies should develop in some of the plates.

Pour plate counts are reported as the count per ml. Pour about 15 ml of the melted agar into each mm petri dish. Keep covers opened slightly until agars have hardened and mois- ture or condensation have evaporated. Close dishes and store in refrigerator. Warm at room temperature before use. The dilutions should bracket the estimated density of bacteria. The analyst must remember that if only 0. Inoculate agar plates. Cool for 15 seconds. Test glass rod on edge of agar to verify safe temper- ature before use.

This step can be simplified by making and sterilizing a number of glass spreaders. Position spreader so that the tip forms a radius from the center to the plate edge. Holding spreader motionless, rotate plate several revolutions, or hold plate and move the spreader in a series of sweeping arcs.

The purpose is to spread the inoculum uniformly over the entire surf ace of the agar. Cover plate par- tially, leaving open slightly to evaporate excess moisture for minutes. These combined digits are termed the Signifi- cant Figures S. If the analyst were reporting that same number to two significant figures, he would report the first figures, 1, as certain, the second figure, 2, as uncertain, and the third figure, 4, as unknown.

Hence he would report it as , inserting the zero only as a spacer. Of course, zeros can be significant in counts of 10,60,, etc. The number of significant figures are equal to the number of colonies.

Membrane Filtration Method 3. The sample is filtered as soon as possible after collection. After the sample is filtered, the membrane filter is placed on a nutrient medium formulated to encourage growth of the bacteria for which the. After incubation under the specified conditions, the bacteria retained on the surface of the membrane develop into visible colonies.

The medium and the temperature of incubation influence the kinds and appearance of bacteria that develop. Two-step enrichment and delayed incubation MF procedures can also be used. The two-step procedure involves an acclimation period on another medium before the selective growth step. Definitive results for total and fecal coliforms can be obtained in hours, whereas hours are required for the multiple-tube fermentation method. With waters of low bacterial densi- ties such as finished waters, larger sample aliquots can be used to enhance the reliability of the results.

Other samples may contain algae. These substances can clog the filter pores and prevent filtration or can cause the development of spreading bacterial colonies. When the bacterial counts of such samples are high, a smaller volume or a higher sample dilution can be used to minimize the effect of sample turbidity.

The membrane filter method may be used with samples containing turbidity by filtration of several smaller replicate sample volumes and compositing the results.

However, with waters of high turbidity and low bacterial count, the membrane filter method may not be applicable. In the latter situation the multiple-tube procedure should be used.

These are wrapped with alumi- num foil or kraft paper and sterilized. See Fig- ure ll-C-7 for an exploded view of a stainless steel MF assembly and filter. Such vacuum- producing devices should be equipped with a check valve to prevent the return flow of air. Filter manifolds to hold a number of filter bases are optional. The paper should be of high quality and free of sulfites or other substances that could inhibit bacterial growth. Dispos- able applicator sticks or plastic loops as alter- natives to inoculation loops.

If the medium is an agar, cool to room temperature. Use sterile forceps for manipulation of absorbent pads and mem- brane filters, contacting the outer edges only, to avoid touching the filtering area or damag- ing the membrane filter surface. Sterilize for- ceps by immersing the tips in ethanol and flaming. Place absorbent pad in bottom of 50 or 6O mm petri dish. Add 1. Saturate but do not flood the pad. Tip the petri dish to drain off excess, if agar medium is used, add about ml to a depth of mm in the petri dish.

Mark each dish to identify the sample, volume or dilution to be filtered. The membrane filter is now fitted between the funnel and the base. Measure the desired volume of sample into the funnel with the vacuum turned off. To measure the sample accurately and to obtain good distri- bution of colonies on the filter surface, the following methods are recommended: a Sample volumes of 20 ml or more: Measure the sample in a sterile graduated cyl- inder and pour it into the funnel.

Rinse the graduate twice with sterile dilution water, and add the rinse water to the funnel. For potable waters, ml volumes may be measured directly in a precalibrated funnel.

Leave the vacuum on and rinse down the funnel walls at least twice with ml of sterile dilution water. Turn off vacuum. An ultraviolet sterilizer unit can be used to hold and sterilize the funnel be- tween filtrations. At least 2 minutes exposure time is required for funnel decontamination 6. Protect eyes from UV irradiation with glasses, goggles, or an enclosed UV chamber 7. Slide the filter onto the absorbent pad or agar, using a rolling action to avoid trapping air bubbles between the membrane filter and the underlying pad or agar.

Reseat the membrane if non-wetted areas occur due to air bubbles. Some colonies will be in contact with grid lines. A suggested procedure to reduce error in counting these colonies is shown in Figure ll-C Count the colonies in the squares indicated by the arrows.

Count colonies individually, even if they are in contact with each other. The technician must learn to recognize the difference between two or more colonies which have grown into con- tact with each other and single, irregularly shaped colonies which sometimes develop on membrane filters. The latter colonies are usu- ally associated with a fiber or paniculate ma- terial and the colonies conform to the shape and size of the fiber or particulates.

Colonies which have grown together almost invariably show a very fine line of contact. By inspection he would select the membrane filter s with coli- form colonies and then limit his actual count- ing to such membranes. Colonies are counted in squares indicated by the arrow. For example, assume that volumes of 0. In this example, two volumes, 0. Here, no colony count falls within recom- mended limits. Report as: No Result and specify reason.

Failure to agree within these limits should trigger a review of procedures. Decimal dilutions of samples are inocu- lated in series into liquid tube media. The MPN procedure may be carried to three stages of completion: The Presumptive Test provides a preliminary estimate of bacterial density based on enrichment in minimally-restrictive tube media. The results of this test are never used without further analyses, 4. Growth from each positive Presumptive Test tube is inoculated into a more selective inhibi- tory medium.

The tubes are incubated at the prescribed temperature and time, the positive reactions noted and counts calculated from the MPN table. Positive tubes from the Confirmed Test are submitted to additional tests to verify the identification of the isolated microorganisms. Although the Completed Test provides the greatest reliability, the amount of time and the workload restrict its use to periodic substantiation of Confirmed Test results, to other QC checks on methodology and analysts, and to research.

The tests require minimal experience, training or interpretation by the analyst. Water bath at See This Section 5. See Part IIB. See Partll-B,7. Use five rows for samples of unknown density. Inoculate each successive row with decreas- ing decimal dilutions of the sample.

For exam- ple, in testing polluted waters for total coli- forms, the initial sample inoculations might be 0. This series of sam- ple volumes would yield determinate results from test waters containing up to 16,, organisms per ml by use of the MPN tables.

When removing sample aliquots or dilu- tions for further inoculations, do not insert the pipet tip more than 2. A positive presumptive test is gas production for the coliforms or growth for fecal strepto- cocci.

Inocu- late positive tubes into Confirmed Test media. If there is no gas or growth reincubate these negative tubes for an additional 24 hours. If the Pre- sumptive tubes are positive, the cultures are verified in the Confirmed Test. Record the negative and positive results. If Presumptive tubes are positive at 24 hours, confirm them at that time. Discard negative tubes. Retain positive tubes if the test is to be carried to completion for total coliform tests. Gas production is the posi- tive reaction.

However, for quality control, at least five percent of the Con- firmed Test samples and a minimum of one sample per test run should be carried through the Completed Test. Pick typical coliform colonies or atypical colonies if no typical colonies are present , inoculate into lauryl tryptose fermen- tation tubes and incubate at 35 C for hours.

The formation of gas in any amount in the fermentation tubes constitutes a positive Completed Test for total conforms. Typical colonies show a golden green metallic sheen or reddish purple color with nucleation. Atypical colonies are red, pink or colorless, unnucleated and mucoid.

Although the gram stain procedure is proposed for revision of the 15th edition of Standard Methods, it provides a final check on results and remains useful for evaluating ques- tionable colony types. After incubation of the EMB agar plates for 24 hours at 35 C in 4. Incubate for 24 hours at 35 C, and proceed as in 5, this Section.

For example in Table ll-C-4 if five 10 ml, five 1. The significant dilutions are selected using the following rules: a Only three dilutions are used in the code for calculating an MPN value. However, if negative tubes are present, e. Collect fresh samples for analyses. Report the MPN values of solid type samples on the basis of 1 gram of dry weight sample.

Examples of bench forms are shown in Figuresll-C-1,2and3. For quality control, prepare a separate smear of known gram positive cocci and gram negative rods. Allow it to remain for one minute. Staining Procedures 5. Mix the bacteria with the drop of water on the slide and spread evenly over an area the size of a quarter. Use loop for broth cultures.

Wash and air-dry. Gram positive cells retain the crystal violet stain and are blue in color. Gram negative cells are decolorized by the acetone alcohol so that they accept the safranin counterstain and appear pink to red. After crystals are in solution, add sufficient laboratory pure water to bring the final solution to a volume of ml. Store as a stock solution. For working solution, add 10 ml of stock to ml of laboratory pure water, mix and store.

Shipment of Cultures 6. The selected cultures should be sent to an official typing center or state health laboratory with pertinent information for the confirmatory identification. This service is usu- ally available if the cultures are of public health significance, but permission should be ob- tained from the reference laboratory before sending cultures. Observe the following instructions: 6.

Triple sugar iron agar or other sugar- containing agars should not be used. Include form with cultures, but on outside of secondary container. Air freight service is limited in many areas, hence passenger-carrying aircraft must be used for safe and quick service. Strict ship- ping regulations are imposed on such passen- ger service shipments 11 , Packaging and la- beling of the cultures must conform with cur- rent federal shipping regulations for etiologi- cai agents described in: 49 CFR The requirements in 6.

Screw-cap metal mailing tubes should be sealed with tape. NOTE: Multiple secondary containers of cultures, which individually meet the packaging requirements for shipment of 50 ml or less, can be overpacked in a single outer shipping container, provided that the total aggregate volume does not exceed ml. Packaging and Labelling of Microbiological Cultures for Shipment.

Clark, H. Kablerand E. Advantages and limitations of the membrane filter procedures. Water Sewage Works Ships, E. A comparison of the molecular filter technique with agar plate count for enumeration of Escherichia coli.

Snipe, E. Cameron, A comparison of the membrane filter with the most probable number method for coliform determinations from several waters. Jeter and J. Winter, , Technical considerations in applying the membrane filter procedure. Health Laboratory Science Jan , Environmental Monitoring and Support Laboratory, U.

Rhines, C. Cheevers, Decontamination of membrane filter holders by ultraviolet light. Waterworks Association Manning, H. AQC Newsletter 26, July Swaroop, S.

Numerical estimation of B. Indian J. Research The range of variation of the most probable number of organisms estimated by the dilution method. Thomas, H. Bacterial densities from fermentation tubes. Water Works Association Morbidity and Mortality Report, The major problems that have developed in. Methodology 1. Problems in Application 2.

Recommendations for Methods in Waters and Wastewaters 1. These documents are generally available in Ohio public libraries and the state library of Ohio. These documents may also be obtained by writing to "U.

Box , Cincinnati, OH" Documents listed with an address may also be obtained at that address. Many of these documents may be obtained via online ordering at www. Some documents may be available for purchase, not free of charge. Federal Resource Conservation and Recovery Act corrective action facilities list.

Federal Resource and Conservation Recovery Act generators list. Federal Resource Conservation and Recovery Act information database. Federal Resource Conservation and Recovery Act treatment, storage, and disposal facility list. Gerlach, R. November Office of Remedial Response. Mason, B. July Unified Guidance. Environmental Protection Agency. Office of Policy, Planning and Evaluation. Office of Solid Waste and Emergency Response. OSWER December