United States Environmental Protection Agency Atmospheric Research and Exposure Assessment Laboratory Research Triangle Park NC 27711 Research and Development EPA/600/SR-93/006 April 1993 Project Summary Analysis of Acid Precipitation Samples Collected By State Agencies—Sampling Period January 1990-December 1990 Lloyd S. Shepard This report presents analytical data from the 30 acid precipitation collec- tion sites in the State-Operated Net- work. Samples are collected weekly in plastic bag liners and shipped in 500- mL polyethylene bottles to Global Geochemistry Corporation (the central laboratory for the network). This report contains maps showing the location of each site, plots of analytical data, tables of all field and analytical data, plots comparing field and laboratory pH and conductivity, and information on data quality. Samples are analyzed for pH, strong acid, conductivity, fluoride, chlo- ride, nitrite, phosphate, bromide, nitrate, sulfate, ammonium, sodium, potassium, calcium, and magnesium. The central laboratory renders technical assistance to the collection sites on problems con- cerning pH and conductivity. Each of the ten participating state agencies re- ceives analytical reports for the samples analyzed the previous month. Analyte concentration data are put on tape for later inclusion in the Acid Depo- sition System (ADS) data base. This Project Summary was devel- oped by EPA's Atmospheric Research and Exposure Assessment Laboratory, Research Triangle Park, NC, to an- nounce key findings of the research project that Is fully documented In a separate report of the same title (see Project Report ordering Information at back). Introduction This report presents analytical data from the 30 acid precipitation collection sites in the State-Operated Network. Samples are collected weekly in plastic bags inserted in the buckets and shipped in 500-mL polyethylene bottles to Global Geochem- istry Corporation (the central laboratory for the network). Global Geochemistry ana- lyzes the samples and monthly sends a report of the analytical results to each site. Global Geochemistry also summa- rizes these results on magnetic tape for inclusion in the national acid rain data base, the Acid Deposition System (ADS), funded by EPA. Individuals concerned with the collection and interpretation of acid precipitation sample results will find this report of interest. Overview of Network Operation and Sample Analysis The central laboratory for the State-Op- erated Network, Global Geochemistry Cor- poration (GGC), analyzes weekly acid precipitation samples for pH, strong acid, conductivity, fluoride, chloride, bromide, ni- trate, nitrite, sulfate, phosphate, ammo- nium, sodium, potassium, calcium, and magnesium. Methods and the analytes used for them are listed in Table 1. The State-Operated Network collects weekly samples using a wet/dry bucket collector. Samples are collected in a plastic bag inserted in the bucket; an aliquot of the collected sample is sent to the central laboratory in a 500-mL polyethylene bottle at ambient temperature (except for 1 site which ships samples in a cooler). The locations of the 30 network sites are shown in Figure 1. The central laboratory provides the 30 network sites with plastic bucket liners, Printed on Recycled Paper ------- Table 1. Methods Used for Some Analytes Analyte Analytical Method Methodology pH Conductivity Acidity C1, P04, S04, NO,, F, Br, NO, NH4 Na, K, Ca, Mg EPA Method 150.1 EPA Method 120.1 Gran Titration EPA Method 300.0 EPA Method 350.1 EPA Methods 273.1, 258.1,215.1, 242.1 pH Electrode Conductivity Titration Ion Chromatography Color/metric Atomic absorption for Ca, Mg. Flame Emission for Na, K 500-mL sample bottles, field data sheets, pH and conductivity solutions, and other supplies incidental to collecting and ship- ping a collected rain sample. The central laboratory also provides technical assis- tance whenever it is requested by a field site. This assistance consists mostly of advice on field pH and conductivity mea- surement procedures and equipment. Monthly, the central laboratory sends a report to each state agency describing the analytical results for all samples analyzed from that agency's sites for the last month. The central laboratory also summarizes the analytical results for all 30 sites and sends this summary on magnetic tape to the organization that maintains the Acid Deposition System (ADS) for EPA where they are entered into the ADS data base. Report Contents The report contains a table showing the latitude and longitude of each of the sites. It also contains plots of analytical data for each site during the time period, tables of all field and analytical data, a comparison of analyte concentrations at all sites (fre- quency of occurrence), precipitation- weighted data for each site, plots comparing field and laboratory pH and conductivity, and quality control tables and plots. EPA State Operated Rain Network Figure 1. Location of sampling sites. 'U.S. Government Printing Office: 1993 — 750-071/60223 ------- ------- Lloyd S. Shepard is with Global Geochemistry Corporation, Canoga Park CA 91303. Berne I. Bennett is the EPA Project Officer (see below). The complete report, entitled "Analysis of Acid Precipitation Samples Collected By State Agencies—Sampling Period January 1990-December 1990 " (Order No PB93-144152; Cost: $36.00; subject to change) will be available only from National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at Atmospheric Research and Exposure Assessment Laboratory U.S. Environmental Protection Agency Research Triangle Park, NC 27711 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati, OH 45268 Official Business Penalty for Private Use $300 BULK RATE POSTAGE & FEES PAID EPA PERMIT No. G-35 EPA/600/SR-93/006 ------- |