United States
Environmental Protection
Agency
Atmospheric Research and Exposure
Assessment Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-95/048
May 1995
EPA Project Summary
Analysis of Acid Precipitation
Samples Collected by State
Agencies—Sampling Period
January 1992-December 1992
Lloyd S. Shepard
This report presents analytical data
from the 30 acid precipitation collec-
tion sites in the State-Operated Net-
work that were operational in 1992.
Samples are collected weekly in plas-
tic 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 national
acid deposition data base.
This Project Summary was developed
by EPA's Atmospheric Research and
Exposure Assessment Laboratory, Re-
search Triangle Park, NC, to announce
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
The main 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 snipped
in 500-rnL polyethylene bottles to Global
Geochemistry Corporation (the central
laboratory for the network). Global
Geochemistry analyzes the samples and
monthly sends a report of the analytical
results to each site. Global Geochemistry
also summarizes these results on mag-
netic tape for inclusion in the national acid
deposition data base. Individuals con-
cerned with the collection and interpreta-
tion of acid precipitation sample results
will find this report of interest.
Overview of Network Operation
and Sample Analysis
The central laboratory analyzes weekly
acid precipitation samples for pH, strong
acid, conductivity, fluoride, chloride, bro-
mide, nitrate, nitrite, sulfate, phosphate,
ammonium, sodium, potassium, calcium,
and magnesium. Table 1 describes the
methods used for these analytes.
The State-Operated Network collects
weekly samples using a wet/dry bucket
collector. Samples are collected in a plas-
tic bag inserted in the bucket; an aliquot
of the collected sample is sent to the
central laboratory in a 500-mL polyethyl-
ene! bottle at ambient temperature (except
for one 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 lines, 500-
mL sample bottles, field data sheets, pH
and conductivity solutions, and other sup-
plies incidental to collecting and shipping
a collected rain sample. The central labo-
ratory also provides technical assistance
Printed on Recycled Paper
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Tab/81. Methods Used for Selected Analytes
Analyte Analytical Method
Methodology
pH
Conductivity
Acidity
Cl, P04, SO,
N0y F, Br, NO.
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 Chromatograph
Colorimetric
Atomic absorption
for Ca, Mg; flame
emission for A/a, K
whenever it is requested by a field site.
This assistance consists mostly of field pH
and conductivity measurement 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 data base for EPA.
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-f ield-and analytical -data, a comparison—
of analyte concentrations at all sites (fre-
quency of occurrence), precipitation
weighted data for each site, plots compar-
ing field and laboratory pH and conductiv-
ity, and quality control tables and plots.
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Lloyd S. Shepardis with Global Geochemistry Corp., 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 1992-December 1992," (Order No.
PB95-191342; Cost: $36.50, 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-95/048
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