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
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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
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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
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