Coastal Streams Acidification Study

Program Overview

The Coastal Streams Monitoring Program was a 14-month (May 1984 - June 1985) field study conducted at three watersheds -- Lyons Creek, Morgan Creek, and Granny Finley Branch -- in the Chesapeake Bay region. Stream and precipitation sampling activities were conducted at the three watersheds. However, two primary sites were designated for daily precipitation sampling. One primary site was located within the Lyons Creek watershed, while the other primary site was located in Chestertown, Maryland, at Washington College, approximately midway between the Morgan Creek and Granny Finley Branch watersheds. The field study was designed and conducted by the Academy of Natural Sciences of Philadelphia (ANSP) and its subcontractor, Environmental Science and Engineering (ES&E), under contract to the Maryland Department of Natural Resources, Power Plant Research Program (PPRP). The major objective of the Coastal Streams Monitoring Program was to determine if low pH conditions and elevated aluminum concentrations in coastal streams were coincident with precipitation events and, if appropriate, to determine the extent to which precipitation chemistry affects the duration and magnitude of either acidic or high aluminum events.

The Lyons Creek monitoring site (base elevation 80 ft msl) was located in Calvert County, Maryland, approximately 34 km east-southeast of Washington, D.C., and 62 km south of Baltimore, Maryland, at latitude 38º 45'39" north and longitude 76º 39'00" west. The Washington College (Chestertown) monitoring site (base elevation 65 ft msl) was located in Kent County, Maryland, approximately 45 km east-southeast of Baltimore, Maryland, at latitude 39º 13'26" north and longitude 76º 04'32" west. It was approximately 10 km from the centroid of the Morgan Creek watershed, and 15 km from the centroid of the Granny Finley watershed.

Deposition sample collection activities at the two primary monitoring sites included:

• Daily collection of wet deposition samples (assuming a rainfall event occurred in the previous 24 hours) and monthly collection of bulk (wet plus dry) deposition samples,

• Continuous rainfall volume monitoring, and

• Continuous wind speed, wind direction, and air temperature monitoring.

Additionally, stream sampling activities conducted for this program included:

• Routine biweekly sample collection at one site on each stream, except during March-June when weekly samples were collected,

• Storm event sampling at one site on each stream during eight spring storm events (8-10 samples per storm event), and

• Quarterly longitudinal sampling at six sites on each of the three streams.

The focus of this program description is the precipitation sampling and analysis program. For additional information on the stream sampling program, consult the document Relationships Between Acid Deposition, Watershed Characteristics, and Stream Chemistry in Maryland's Coastal Plain, Final Report (see "Related Reports" section on this website).

Precipitation Sampling

In terms of equipment, the wet precipitation sample collector used at each primary monitoring site was the Aerochem Metrics Model 301 collector. Precipitation totals deposited over the sampling period were measured with a Belfort recording rain gauge (Cat. No. 5-780). This measurement provided rainfall data necessary to cross-check the collection of precipitation by the Aerochem Metrics collector, and the data necessary to calculate deposition rates. The primary monitoring sites also were equipped with event fractionation collectors and bulk deposition sample collectors.

The chemical parameters measured in precipitation samples were ions of calcium (Ca⁺²), magnesium (Mg⁺²), potassium (K⁺), sodium (Na⁺), ammonium (NH₄⁺), nitrate (NO₃^-), chloride (Cl^-), sulfate (SO₄^-2), and laboratory and field hydrogen (H⁺); laboratory and field pH; laboratory and field specific conductance; total acidity; cations; and anions. All laboratory chemical analyses of precipitation samples were performed by ES&E.

Precipitation Sampling and Analysis QA/QC

Both a Field Operations Manual and a Laboratory Operations Manual were prepared for the project team. (Copies of these manuals are provided in the report Relationships Between Acid Deposition, Watershed Characteristics, and Stream Chemistry in Maryland's Coastal Plain, Final Report, Volume VIII: Appendix D.)

The Field Operations Manual provided detailed, step-by-step procedures for collecting the samples, checking and calibrating the instruments, performing field measurements, documenting results, and shipping samples to the laboratory. Rigorous training of field operators in the proper techniques for collecting samples and making field measurements was performed. Quality assurance (QA) reference samples were sent bimonthly to each field operator for measurement of pH and conductivity. If the results of the samples did not meet control criteria, an audit of the field operator’s procedures and equipment was immediately conducted. In addition, semi-annual field audits were conducted to document performance of field operators.

The Laboratory Operations Manual delineated the procedures used from sample receiving through analysis and reporting of data for the project. Specific personnel were designated to log in and label field samples, establish sample lots (batches), distribute samples for analysis, perform the analysis, review and approve the analysis results, and enter the results into the computerized database according to the standard operating procedure outlined in the manual. In terms of analytical systems controls, filter blanks (obtained bi-weekly), washed bucket blanks (obtained bi-weekly), and field bucket blanks (between rain events) were analyzed as part of quality control (QC) procedures. QC checks were performed prior to completion of laboratory analyses (to assure correlation coefficient criteria, recovery, replicate control limit, and instrument drift criteria are met) and input to the database. Additional QC checks were also performed on the data input to the database. A QC check was performed for interparameter consistency: percent difference for cations vs. anions, and predicted versus measured conductance. Semi-annual audits of laboratory operations performance were conducted.

A project QA plan -- Maryland Acid Deposition Regional Assessment Study Project Quality Assurance Plan -- was developed for the project by the ANSP. (A copy of this plan is provided in the report Relationships Between Acid Deposition, Watershed Characteristics, and Stream Chemistry in Maryland's Coastal Plain, Final Report, Volume VIII: Appendix D.) The major objective of the plan was to audit and review the validity of the data collected. The plan provided mechanisms to :

• Monitor and control the management of data to document validity,

• Document the precision, accuracy, and sensitivity of the sampling and analytical system, and

• Recognize deficiencies early and provide a mechanism for correction.

QA-QC reports were prepared quarterly by ANSP that summarized the quality of data generated. Specific QA objectives (i.e., criteria) for precision, data recovery (i.e., completeness), and accuracy were used to ensure generation of reliable and reproducible data of known quality. The ANSP Project Quality Assurance Supervisor served as the overall QA manager for the project.

Summaries of Quarterly QA/QC Reports

The Coastal Streams Monitoring Program first quarterly QA/QC report, which included data for the period May 1, 1984 to June 26, 1984, showed good field and laboratory precision and accuracy. The precision of magnesium and chloride measurements appears to be lower than other ions; however, percent recoveries were in line with those of other ions. Analysis of blanks indicated no potential contamination problems.

The Coastal Streams Monitoring Program second quarterly QA/QC report, which included data for the period June 30, 1984 to October 15, 1984, showed good field and laboratory precision and accuracy. The only significant problem was the apparent presence of significant concentrations of non-measured cations in the precipitation samples. Analysis of blanks indicated no potential contamination problems.

The Coastal Streams Monitoring Program final quarterly QA/QC report, which actually included data for the final 9 months (October 1, 1984 to June 30, 1985) of the study period, showed that the field and laboratory analyses were performed with acceptable accuracy and precision. (A copy of this document is provided in Relationships Between Acid Deposition, Watershed Characteristics, and Stream Chemistry in Maryland's Coastal Plain, Final Report, Volume VIII: Appendix D.) Precipitation chemistry data generated during the monitoring effort met or exceeded the analytical criteria established for the study. Analyses of blanks were generally acceptable, even though magnesium in filter and bucket blanks could have accounted for a significant percentage of total deposition. The significance of this potential contamination can be put into perspective by noting that magnesium accounted for less than 5% of the measured cations at Washington College and Lyons Creek precipitation stations.

Another concern was that of the cation/anion balances. Since anions generally exceeded cations, the implication was that not all cations were being measured or there was a bias in the analysis of either cations or anions. The QA-QC data did not indicate a bias in the analyses. Reanalysis of selected samples and blanks supported the view that certain cations were present in the rain which were not routinely analyzed.

Related Reports

The following documents associated with the Coastal Streams Monitoring Program are available from the Maryland PPRP.  For further information, email Dr. John Sherwell at the PPRP, or call him at 410-260-8660.

• Maryland Acid Deposition Regional Assessment Study, Project Quality Assurance Plan, Prepared by the Academy of Natural Sciences of Philadelphia for the Maryland Power Plant Research Program, June 1, 1984.

• Maryland Acid Deposition Regional Assessment Study, Precipitation Monitoring Program, First Quarterly Report, Prepared by Environmental Science and Engineering, Inc. for the Maryland Power Plant Research Program, August 1984.

• Effects of Acid Deposition on Coastal Feeder Streams: Description of Study Sites (Draft), Prepared by the Academy of Natural Sciences of Philadelphia for the Maryland Power Plant Research Program, September 13, 1984.

• Effects of Acid Deposition on Maryland Coastal Streams: Analysis of first quarter data, Prepared by the Academy of Natural Sciences of Philadelphia for the Maryland Power Plant Research Program, February 25, 1985.

• Effects of Acid Deposition on Maryland Coastal Streams: Second Quarterly Quality Assurance/Quality Control and Data Report, Prepared by the Academy of Natural Sciences of Philadelphia for the Maryland Power Plant Research Program, February 25, 1985.

• State of Maryland Acid Deposition Regional Assessment Study, Quality Assurance-Quality Control Final Quarterly Report, Prepared by the Academy of Natural Sciences of Philadelphia for the Maryland Power Plant Research Program, September 1, 1985.

• Coastal Streams Data Analysis: Phase I Report, Prepared by Versar, Inc., Columbia, Maryland for the Maryland Power Plant Research Program, February 12, 1986.

- Volume I: Text

- Volume II: Appendix C - Stream Water Data Set: Granny Finley Branch

- Volume III: Appendix C - Stream Water Data Set: Lyons Creek (Continued)

- Volume IV: Appendix C - Stream Water Data Set: Morgan Creek (Continued)

- Volume V: Appendix D - Precipitation Chemistry Data Set; Appendix E - Precipitation Chemistry Data Set Levels of Detection and Level of Quantification; Appendix F - Wind Roses for Washington College (WAC) and Lyons Creek (LYC) and Daily Weather Maps; Appendix G - Pollutant Roses for Washington College (WAC) and Lyons Creek (LYC); Appendix H - Precipitation Chemistry Time Series for Selected Variables

• Relationships Between Acid Deposition, Watershed Characteristics, and Stream Chemistry in Maryland's Coastal Plain, Final Report, Prepared by Versar, Inc., Columbia, Maryland, and ERM, Inc., West Chester, Pennsylvania, for the Maryland Power Plant Research Program, June 1987, Report No. AD-87-8.  (This document -- No. PB88-154653 -- is available from the National Technical Information Service.)

  - Volume I: Text

  - Volume II: Appendix A - Calculations and Results of Statistical Analyses

  - Volume III: Appendix B - Data Quality Assurance and Stream, Precipitation, and Meteorological Data

  - Volume IV: Appendix B - Data Quality Assurance and Stream, Precipitation, and Meteorological Data (Continued)

  - Volume V: Appendix B - Data Quality Assurance and Stream, Precipitation, and Meteorological Data (Continued)

  - Volume VI: Appendix B - Data Quality Assurance and Stream, Precipitation, and Meteorological Data (Continued)

  - Volume VII: Appendix C - Site Descriptions

  - Volume VIII: Appendix D - Field and Laboratory Manuals; Appendix E - Quality Assurance Plans