METHODS FOR CHEMlCAL ANALYSIS OF WATER AND WASTES ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY Environmental Research Center Cincinnati, Ohio 45268 i U.S. ENVIRONMENTAL PROTECTION AGENCY Technology Transfer 1974 The mention of trade names or commercial products in this manual is for illustration purposes, and does not constitute endorsement or recommendation for use by the U. S. Environmental Protection Agency. 11 FOREWO I<D The accoml)lishmcnt of our objectives in protecting the environ~nr~eq~u~ir~est at1 ;iwaretic'cs of the i ii t er d e pc ti d e tic c of the coni po ti e ti t s we seck to p ro 1e c t - air , w ;I t e I-, a nd I ;i 11d . TI1 1-0u gh i n d i vi d ii; II and joint efforts the National I3ivironnicntal Research Centers provide this ~nultidisciplinaryf ocus through programs cngaged in studies on the effects of environmental containinants on 111311 and the biosphcrc, the devel o p i et it of e ffi cien t means of nio ni t ori ng these con t a ti1 i na n t s , and a search for more effective ways to prcvent ~indcsirablen iotlification of tlie environinent and the recycling of valuable resources. This chemical methods manual was developed by the staff of the Environmental Monitoring and Support Laboratory, formerly known as the Mcthods Development and Quality Assurance Kesearcli Laboratory (MDQAIIL) of the National Environmcntal Research Center, Cincinnati, to providc methodology for iiioni toring tlie qiiality of our Nation's waters and to detcmiine the inip;ict of waste discharges. The test procedures have been caref~illys elected to meet the needs of laboratories engaged in plotccting the aquatic environment. The contributions and counsel of scientists in other EPA laboratories are gratcfully acknowledged. .lhe manual is published and distributcd by the Office of Tcchnology Transfer, as one of a series tlesigucd to insiire tliat the latcst technologies developed by EPA and private industry are disseminated to states, niunicipali tics and industries who are responsible for environmental pollution control. _. 1 lie other manuals in this series arc: Thew are also available through tlic Ofl'ice of Technology Transfer, Cincinnati, Ohio 45 208. . KO be rt I I. Crow c 11 i rect o r Dwight G. 13;illingcr OTficc of Technology Transfer 11 irector, Environmental Monitoring and Cincinnati, Ohio 45268 S ii p por t Labo ra t or y , Cincinnati, Ohio iii INTRODUCTION , -’ This second edition of “Methods for Chemical Analysis of Water and Wastes” contains the chemical analytical procedures used in U.S. Environmental Protection Agency (EPA) laboratories for the examination of ground and surface waters, domestic and industrial waste effluents, and treatment process samples. Except where noted under “Scope and Application,” the methods are applicable to both water and wastewaters, and both fresh and saline water samples. The manual provides test procedures for the measurement of physical, inorganic, and selected organic constituents and parameters. Methods for pesticides, industrial organic waste materials, and sludges are given in other publications of the Agency. The methods were chosen through the combined efforts of the EPA Regional Analytical Quality Control Coordinators, the staff of the Physical and Chemical Methods Branch, Methods Development and Quality Assurance Research Laboratory, and other senior chemists in both federal and state laboratories. Method selection was based on the following criteria: (1) The method should measure the desired property or constituent with precision, accuracy, and specificity sufficient to meet the data needs of EPA, in the presence of the interfering materials encountered in water and waste samples. (2) The procedure should utilize the equipment and skills available in modern water pollution control laboratories. (3) The selected method is in use in many laboratories or has been sufficiently tested to establish its validity. (4) The method should be rapid enough to permit routine use for the examination of a large number of samples. Instrumental methods have been selected in preference to manual procedures because of the improved speed, accuracy, and precision. In keeping with this policy, procedures for the Technicon AutoAnalyzer have been included for laboratories having this equipment available. Precision and accuracy statements are provided where such data are available. These statements are derived from interlaboratory studies conducted by the Quality Assurance and Laboratory Evaluation Branch, Methods Development and Quality Assurance Research Laboratory; the American Society for Testing Materials; or the Analytical Reference Service of the US Public Health Service, DHEW. iv These methods may be used for measuring both total and dissolved constituents of the sample. When the dissolved concentration is to be determined, the sample is filtered through a 0.45-micron membrane filter and the filtrate analyzed by the procedure specified. The sample should be filtered as soon as possible after it is collected, preferably in the field. Where field filtration is not practical, the sample should be filtered as soon as it is received in the laboratory. Many water and waste samples are unstable. In situations where the interval between sample collection and analysis is long enough to produce changes in either the concentration or the physical state of the constituent to be measured, the preservation practices in Table I1 are recommended. This manual is a basic reference for monitoring water and wastes in compliance with the requirements of the Federal Water Pollution Control Act Amendments of 1972. Although other test procedures may be used, as provided in the Federal Register issue of October 16, 1973 (38FR 28758), the methods described in this manual will be used by the Environmental Protection Agency in determining compliance with applicable water and effluent standards established by the Agency. Although a sincere effort has been made to select methods that are applicable to the widest range of sample types, significant interferences may be encountered in certain isolated samples. In these situations, the analyst will be providing a valuable service to EPA by defining the nature of the interference with the method and bringing this information to the attention of the Director, Methods Development and Quality Assurance Research Laboratory, through the appropriate Regional AQC Coordinator. V SAMPLE PRESERVATION Complete and unequivocal preservation of samples, either domestic sewage, industrial wastes, or natural waters, is a practical impossibility. Regardless of the nature of the sample, complete stability for every constituent can never be achieved. At best, preservation techniques can only retard the chemical and biological changes that inevitably continue after the sample is removed from the parent source. The changes that take place in a sample are either chemical or biological. In the former case, certain changes occur in the chemical structure of the constituents that are a function of physical conditions. Metal cations may precipitate as hydroxides or form complexes with other constituents; cations or anions may change valence states under certain reducing or oxidizing conditions; other constituents may dissolve or volatilize with the passage of time. Metal cations may also adsorb onto surfaces (glass, plastic, quartz, etc.), such as, iron and lead. Biological changes taking place in a sample may change the valence of an element or a radical to a different valence. Soluble constituents may be converted to organically bound materials in cell structures, or cell lysis may result in release of cellular material into solution. The well known nitrogen and phosphorus cycles are examples of biological influence on sample composition. Methods of preservation are relatively limited and are intended generally to (1) retard biological action, (2) retard hydrolysis of chemical compounds and complexes and (3) reduce volatility of constituents. Preservation methods are generally limited to pH control, chemical addition, refrigeration, and freezing. Table I shows the various preservatives that may be used to retard changes in samples. vi TABLE 1 Preservative Action Applicable to: Bacterial Inhibitor Nitrogen forms, HgCl2 Phosphorus forms Acid (H N03) Metals solvent, pre- Metals vents precipitation Acid (H2 SO4 ) Bacterial Inhibitor Organic samples (COD, oil & grease organic carbon), Ni trogen-phosphorus forms Salt formation with Ammonia, amines organic bases Alkali (NaOH) Salt formation with Cyanides, organic volatile compounds acids Refrigeration Bacterial Inhibitor, Acidity-alkalinity , Retards chemical organic materials, reaction rates BOD, color, odor, organic P, organic N, carbon, etc., biological organism (coliform, etc.) In summary, refrigeration at temperatures near freezing or below is the best preservation technique available, but it is not applicable to all types of samples. The recommended choice of preservatives for various constituents is given in Table 2. These choices are based on the accompanying references and on information supplied by various Regional Analytical Quality Control Coordinators. vii TABLE 2 RECOMMENDATION FOR SAMPLING AND PRESERVATION OF SAMPLES ACCORDING TO MEASUREMENT (1 ) VOl. Req. Holding Measurement (ml) Container Preservative Time(6) Acidity 100 Cool, 4°C 24 Hrs. Alkalinity 100 Cool, 4°C 24 Hrs. Arsenic 100 HN03 to pH <2 6 Mos. BOD 1000 Cool, 4°C 6 H~s.'~) Bromide 100 Cool, 4°C 24 Hrs. COD 50 H2S O4 to pH <2 7 Days Chloride 50 None Req. 7 Days Chlorine Req. 50 Det. on site No Holding Color 50 Cool, 4°C 24 Hrs. Cyanides 500 Cool, 4°C 24 Hrs. NaOH to pH 12 Dissolved Oxygen Probe 3 00 Det. on site No Holding Winkler 3 00 Fix on site 4-8 Hours viii TABLE 2 (Continued) ~~ VOl. Req. Holding Measurement (ml) Container Preservative Time(6) ___ Fluoride 300 p, G Cool, 4°C 7 Days Hardness 100 p, G Cool, 4°C 7 Days HNO, to pH <2 Iodide 100 p, G Cool, 4°C 24 Hrs. MBAS 250 p, G Cool, 4°C 24 Hrs. Metals Dissolved 200 p, G Filter on site 6 Mos. HNO, to pH <2 Suspended Filter on site 6 Mos. To tal 100 HNO, to pH <2 6 Mos. Mercury Dissolved 100 p, G Filter 38 Days HN03 to pH <2 (Glass) 13 Days (Hard Plastic) Total 100 38 Days (Glass) 13 Days (Hard Plastic) ix TABLE 2 (Continued) ~. VOl. Req. Holding Measurement (mu Container Preservative Time( 6) Nitrogen Ammonia 400 Cool, 4°C 24 H~s.)( ~ H2S O, to pH <2 Kjeldahl, 500 Cool, 4°C 7 Days total H2S04t o pH <2 Nitrate 100 Cool, 4°C 24 H~s.(~) H2S O, to pH <2 Nitrite 50 Cool, 4°C 24 Hrs. (4) NTA 50 Cool, 4°C 24 Hrs. Oil & Grease IO00 Cool, 4°C 24 Hrs. H2S04 or HC1 to pH <2 Organic Carbon 25 Cool, 4°C 24 Hrs. H2 SO, to pH <2 25 Cool, 4°C 6 HI-s.(~) Det. on site Phenolics 500 Cool, 4°C 24 Hrs. H,PO, to pH <4 1.0 g CUSO,/l Phosphorus Ortho- phosphate, 50 Filter on site 24 Hrs.(, Dissolved Cool, 4°C X