United States
                    Environmental Protection
Environmental Monitoring
Systems Laboratory
Las Vegas NC 89193
                    Research and Development
EPA/600/S8-87/024  Jan. 1988
s>EPA          Project  Summary
                   Wet Deposition  and  Snowpack
                    Monitoring Operations  and
                    Quality Assurance  Manual

                    D. J. Chaloud, L. R. Todechiney, R. C. Metcalf, and B. C. Hess
                     The manual (User's Guide) summa-
                    rized herein presents the quality assur-
                    ance plan and operations protocols for
                    a comparative study of snow collection
                    instruments being conducted on Mt.
                    Evans. Instruments to  be  compared
                    include the Aerochem Metrics Model
                    301 wet/dry deposition collector, the
                    Belfort  Model 780-5 weighing-rain
                    gage, and  18 inch-diameter  flanged
                    bulk samplers.  In addition,  ground
                    measurements are made to provide a
                    "ground  truth" standard. Primary
                    project objectives include assessment
                    of operational reliability, estimation of
                    inter-instrument and temporal variabil-
                    ity, comparison of water equivalent and
                    matrix chemistry between the collec-
                    tion devices  and ground  measure-
                    ments, and recommendation of instru-
                    ments and sampling intervals for future
                    high altitude, complex terrain monitor-
                    ing. The protocols related to quality
                    assurance, quality control, calibration,
                    operation, maintenance, processing,
                    analysis, and data management are
                    described. The manual is considered to
                    be of greatest benefit to field operators,
                    laboratory analysts, and project man-
                     This Project Summary was devel-
                    oped by EPA's Environmental Monitor-
                    ing Systems Laboratory. Las Vegas,
                    NV. to announce key findings of the
                    research project that  is fully docu-
                    mented in a separate report of the same
                    title (see  Project Report ordering
                    information at back).

  Established acidic deposition monitor-
ing networks largely neglect the  high
elevation areas of the western United
States. Interest in these areas is growing,
particulary for the Rocky Mountain
region, because of evidence that precip-
itation amount, and possibly total chem-
ical loading,  is strongly correlated  with
elevation.  Most monitoring equipment
and siting criteria were developed for
low-elevation, flat-land sites.  Meteorol-
ogy in mountainous terrain  is  signifi-
cantly more complex, and  precipitation
levels are  higher than at low-elevation
sites. Research  on  the suitability of
existing instruments for use at  high
altitude is  needed before large funding
and personnel resources are committed
to monitoring acidic deposition in moun-
tainous terrain.

 The National Atmospheric Deposition
Program (NADP), EPA Region VIII, and
U.S. Forest Service are participating in
an investigation  of  equipment  perfor-
mance at high altitude. The EPA Envi-
ronmental  Monitoring Systems Labora-
tory in Las Vegas, Nevada (EMSL-LV),
and the prime contractor for EMSL-LV,
Lockheed Engineering and Management
Services Company, Inc.  (Lockheed-
EMSCO), are responsible for equipment
installation, field station operation, and
data  interpretation.  EMSL-LV  and
Lockheed-EMSCO have primary respon-
sibility for construction of the monitoring
platform,  installation  of  equipment,
operator training,  snow density/coring

activities, data verification and interpre-
tation,  chemical analyses, and  quality
assurance. Instruments to be evaluated
include  the  Aerochem Metrics Model
301  wet/dry deposition collector,  the
Belfort  weighing-rain gage, and  bulk
samplers.  Snow density,  snow  coring,
and  event sampling also are being
undertaken to provide a "ground truth"
comparison. Samplers are  to be evalu-
ated in  terms of reliability and ease of
operation, catch efficiency, and resultant
sample matrix chemistry. Meteorological
sensors located on the monitoring  plat-
form will  provide  information on  the
meteorological  environment  surround-
ing the collectors.
  The selected site is the High Altitude
Laboratory operated by the University of
Denver. The High Altitude Laboratory is
located  adjacent to  the Mount Evans
highway near Echo Lake, 14 miles south
of Idaho Springs,  Colorado.  The  site
offers several advantages: the terrain is
complex, and the area is subject to large
amounts of precipitation and to  high
winds;  the site is  accessible  even in
winter;  it has electrical power, and it is
inhabited year-round. A National  Oce-
anic and  Atmospheric Administration
(NOAA) monitoring station located near
the  monitoring  platform  can provide
additional meteorological information.
  This  manual details the equipment
operation, chemical analyses, andquality
assurance plan for the wet  deposition
and  snowpack  monitoring  project.  It is
designed to be of primary benefit to the
station operator, laboratory analysts, and
data analysts. The protocols presented
here may be  revised over the course of
the program to reflect necessary changes
and improvements  m   procedures.
Related documents include  an opera-
tions status report which will be deliv-
ered in June  1987 and a final report on
the  evaluation results which will be
provided in January 1988.

Project Description
  Snowpack  and wet deposition moni-
toring  on Mount Evans is being  con-
ducted to assess the suitability of
selected  collection  devices  to  high
altitude, complex  terrain situations.
Specific objectives of the project are as

 • Inter-instrument sampling  variability
   for two colocated wet/dry collectors
   will be estimated by comparing chem-
   istry and water equivalent for weekly
 • Inter-instrument sampling variability
   for two colocated Belfort weighing-
   rain  gages  will  be estimated by
   comparing water equivalent for event
   and weekly data.

 • Temporal variability will be estimated
   by comparing  chemistry and  water
   equivalent of wet/dry collector event
   samples to weekly samples.

 • Inter-instrument sampling variability
   for two colocated bulk samplers will
   be estimated by comparing chemistry
   and water equivalent for weekly

 • A "ground truth standard" for esti-
   mating the accuracy of all collection
   instruments will be  estimated by
   comparing sample chemistry to the
   chemistry of snowpack cores taken to
   snowboards. The comparison will be
   made on samples collected  after

 • A "ground truth standard" for esti-
   mating the accuracy of all collection
   instruments will be provided by com-
   paring  water equivalent of samples
   collected after events and collected
   weekly. The comparison will be made
   on snow pit density measurements
   and on snowboard measurement.

• Instruments and sampling intervals
  for high  altitude, complex  terrain
  situations will be recommended based
  on  results  of  all  the  above

 • Operational   reliability  will  be
   assessed in qualitative terms of types
   of instrument malfunctions, length of
   downtime, cause and resolution of
   problems, ease of operation, fre-
   quency and difficulty of maintenance,
   and sample contamination.
   The wet/dry collector and Belfort rain
 gage are the standard instruments used
 by NADP and by other major monitoring
 and research  networks. The  Belfort
 gages are unshielded. The bulk sampler
 design is identical to that used  by the
 United States Geological Survey (USGS)
 in snow studies. Supplemental  instru-
 mentation includes Science Associates
 Models 424-1 and 424-2 wind speed/
 wind direction  sensors and  a data
 acquisition system (DAS) composed of an
 IBM at personal computer and Metrobyte
 logic boards. Snow coring equipment and
 the Taylor-LaChapelle snow-density kits
used  are manufactured by  Hydro-Tech.I
Snowboards are fabricated by Lockheed-
EMSCO   of   polyurethane-coated
  The collection devices and meteorolog-
ical sensors are mounted on a  20-foot
diameter octagonal  wooden  platform
erected on  a southeast-facing slope at
the maximum expected snowpack height
(19 feet at the point closest  to the
ground). Cables connect the sensors to
the DAS which  is located approximately
275 feet distant in a heated building. The
platform is accessed by steps located on
the uphill (NNE) side. The closest tree
tops subtend an angle of 47° ±  3°. The
nearest of several buildings is located 28
feet NNW of the platform. A fireplace in
one of these  buildfngs is' a possible
source of contamination; however, the
building is more than 500 feet away and
is shielded by  other buildings  and by
  The  monitoring equipment and DAS
are checked daily by an  on-site operator.
In addition,  a Lockheed-EMSCO scientist
visits  the site at least once a  month.
During most of the study, samples are
collected from  two wet/dry collectors
and two bulk samplers on a weekly basis
or more frequently as required by event
loading. Samples are collected from the {
third wet/dry collector daily. Snowboard
cores and  snow pit density measure-
ments are  taken weekly. During a 30-
day period, two wet/dry collectors are
operated on a daily basis, and the third
is operated on a weekly basis. Snow
cores and  snow pit density measure-
ments are taken daily as well as weekly
during this  same 30-day period.
  No analyses are performed in the field.
On a  weekly  basis,  all samples are
shipped frozen  to Lockheed-EMSCO in
Las Vegas,  Nevada, where water equiv-
alents are determined and where melted
samples are  processed.  Processing
includes pH and specific conductance
measurements,  which are completed
immediately after melting, and filtration
and preservation of aliquots for subse-
quent analysis. Analyses for chloride and
ammonium are completed approximately
every  two  weeks;  analyses for metal
cations,  nitrate, and sulfate are  com-
pleted every four weeks. All analyses are
completed within recommended  holding
times for the chemical variable of  interest
and preservation treatment used.
  Data from the field, processing labor-
atory, and analytical laboratory are
compiled into a single database; because
of the small size of the database, an IBM- (

PC is used for data compilation. Quality
control sample  data are used to verify
the data; data of poor or unknown quality
are deleted.
  Statistical tests, including  paired t-
tests, %RSD, and means, are employed
to quantify the project objectives. Other
interpretative schemes  may  be  deve-
loped dependent upon the initial intra-
and inter-comparison results.

Quality Assurance Plan
  The Quality Assurance (QA) policy of
EPA  requires that every monitoring and
measurement project have a written and
approved QA project plan. This require-
ment applies to all environmental mon-
itoring and measurement efforts autho-
rized or supported  by EPA through
regulations,  grants, contracts, or other
formal means.  The QA project  plan
should specify the policies, organization,
objectives,  functional activities,  and
specific quality  control (QC) procedures
designed to achieve the data quality goals
of the project. As used herein, QC is the
specific procedures and checks used to
provide a quality product, while QA is the
overall system used to ensure that the
QC system  is  performing.  All  project
personnel should be familiar with the
policies and objectives outlined in the
operations and QA plan to ensure proper
interactions  among the field operations,
laboratory   operations,   and   data

Quality Assurance Objectives
  QA objectives are defined in terms of
percision, accuracy,  completeness,
representativeness, and comparability.

Precision and Accuracy
  The  QA objectives' fbr precision  and
accuracy of the parameters  being mea-
sured are given in the manual. Precision,
defined as the mutual agreement among
individual  measurements of the same
property, is expressed in terms of percent
relative standard deviation  (%RSD).
Precision is  calculated from results of
duplicate analyses and repetitive  ana-
lyses of audit samples and quality control
check solutions. Accuracy is the degree
of agreement of a measurement with an
accepted  or  true value. It is expressed
as percent bias  and is determined from
the difference between recorded mea-
surements and accepted true values of
audit  samples,   quality  control check
solutions, and calibration standards.
  An additional estimate of precision  is
provided by the two colocated wet/dry
collectors,  Belfort rain gages, and bulk
samplers. It is common practice in many
studies to  designate one unit as the
primary or routine sampler and the other
as a secondary or duplicate sampler. This
practice, in effect, designates  samples
from the secondary unit as QC samples.
  Because  one of the project objectives
is estimation of inter-instrument  sam-
pling variability  (i.e., quantification of
precision limits), units used inthis project
will  not receive primary and secondary
designations. Consequently, a  field
duplicate is not included  as one of the
QC samples described  below.  Analysis
of the  data on  colocated samplers  is
included  in the data  interpretation
scheme, as discussed in the manual.

Field  Operations
  The  equipment installed at the mon-
itoring site includes wet/dry collectors,
Belfort rain gages, bulk samplers,  wind
speed and wind direction  sensors and a
data acquisition system  (DAS). All of
these, with the exception of the DAS, are
mounted on the raised  sampling  plat-
form.  Additional  measurements are
taken on the ground within a  clearing.
Snowboards  provide a  base for  core
samples which are collected on an event
and weekly basis.  Density measure-
ments  are performed  in  a snow pit.
Responsibilities of the  site  operator
include sample collection, handling, and
shipment; instrument calibration, main-
tenance, and  quality control  checks;
equipment  trouble-shooting and repair;
and documentation of all field activities.
The  following  sections detail  each of
these aspects of field operations; ground-
level measurements  are treated  in  a
separate section of the manual.

Analytical Operations
  All processing and analytical activities
are performed by Lockheed-EMSCO in
facilities provided by  EPA EMSL-LV.
Processing  operations,  including water
equivalent  determination, aliquot prep-
aration, specific conductance  and pH
measurements,  and field  operations
support are initiated immediately upon
receipt  of samples and  are concluded
within  48  hours of  receipt of frozen
samples. Every two weeks, the aliquots
that have been  prepared  and accumu-
lated for chloride and ammonium deter-
minators are analyzed; every four weeks
the accumulated aliquots for cations (Na,
K, Ca,  and  Mg)  and nitrate and sulfate
determinations are analyzed. The accum-
ulated aliquots that are analyzed at one
time are considered a unique batch.

Data Management
  Most data for this program are provided
on floppy disk. A limited amount of data
must be manually entered (e.g., Belfort
rain gage  data).  Hand-entered data are
reviewed  for transcription accuracy.
Evaluation of data quality is described in
the manual.  Following this evaluation,
data  of poor or  unknown quality are
removed from the data base. Operator
records are  reviewed, and data  corres-
ponding to calibrations, quality  control
checks, maintenance activities, or mal-
functions are removed.
  The remaining verified data are ana-
lyzed and interpreted in accordance with
the project objectives. Inter-instrument
comparisons are made for instruments
of the same model  operating over the
same sampling interval. These include
the two Belfort rain gages, the two bulk
samplers,  duplicate  weekly and  daily
snow  cores, paired weekly wet/dry
collectors, and  paired  daily wet/dry
collectors. Comparisons are made of the
water equivalent and chemistry results.
Specific comparisons include computa-
tion of means, range, %RSD, and paired
  Comparisons between different instru-
ment  models employ  statistical tests
similar to those  described  above. All
instruments  operating  over the same
sampling interval are intercompared with
intercomparison  being based on  water
equivalent and  chemistry results.  In
addition, comparisons are made of same
model and different  model instruments
operating over different sampling inter-
vals. This comparison of daily and weekly
samples is made possible by integration
of daily samples to create a "synthetic"
weekly sample.  Graphics are also used
to illustrate temporal variability results.
  The  water equivalent and chemistry
results of  each  instrument are also
compared to ground truth measure-
ments. The ground truth measurements
include snow pit  density measurements
(water equivalent only) and snow cores
(chemistry  and water  equivalent).  To
make these  comparisons, the  inter-
instrument and spatial  variability must
be  quantified; comparisons  between.
instruments  and ground truth measure-
ments are  generally made on  means
rather than on individual sample data.

    Operational reliability is assessed on
  the basis of field documentation and data
  quality. Statistical analyses, comparison
  to ground truth, and operational reliabil-
  ity are all  considered in the evaluation
  of recommended instruments and sam-
  pling intervals; this is the substance of
  the final project objective.
         D. J. Chaloud, L. R. Todechiney, R. C. Metcalf, and B. C. Hess are with Lockheed
           Engineering and Management Services Co., Inc., Las Vegas, NV 89114.
         W. L. Kinney is the EPA Project Officer (see below).
         The complete  report  entitled "Wet Deposition and Snowpack Monitoring
           Operations and Quality Assurance Manual," (Order  No. PB  87-212 817/
           AS; Cost: $18.95, 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:
                Environmental Monitoring Systems Laboratory
                P.O. Box 93478
                U.S. Environmental Protection Agency
                Las Vegas. NV 89193
United States
Environmental Protection
Center for Environmental Research
Cincinnati OH 45268
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