1. Preface

   • Avis Newell

   EditorialNotes Pages: v - v

2. Perspectives on environmental monitoring: An introduction to the U.S. EPA Long-Term Monitoring (LTM) Project

   • Jesse Ford
   • John L. Stoddard
   • Charles F. Powers

   OriginalPaper Pages: 247 - 255

3. Inter-regional comparison of patterns and trends in surface water acidification across the United States

   • Avis D. Newell

   OriginalPaper Pages: 257 - 280

4. Recent trends in the acid-base status of surface waters in Maine, USA

   • Jeffrey S. Kahl
   • Terry A. Haines
   • Ronald B. Davis

   OriginalPaper Pages: 281 - 300

5. Trends and patterns in lake acidification in the State of Vermont: Evidence from the Long-Term Monitoring Project

   • John L. Stoddard
   • James H. Kellogg

   OriginalPaper Pages: 301 - 317

6. Seasonal and long-term temporal patterns in the chemistry of Adirondack lakes

   • Charles T. Driscoll
   • Richard Van Dreason

   OriginalPaper Pages: 319 - 344

7. Identifying sources of snowmelt acidification with a watershed mixing model

   • Douglas A. Schaefer
   • Charles T. Driscoll

   OriginalPaper Pages: 345 - 365

8. Chemical characteristics and temporal trends in eight streams of the Catskill Mountains, New York

   • Peter S. Murdoch
   • John L. Stoddard

   OriginalPaper Pages: 367 - 395

9. Temporal trends in low alkalinity lakes of the Upper Midwest (1983–1989)

   • Katherine E. Webster
   • Patrick L. Brezonik
   • Bruce J. Holdhusen

   OriginalPaper Pages: 397 - 414

10. Use of chemistry and stable sulfur isotopes to determine sources of trends in sulfate of Colorado lakes

    • John T. Turk
    • Donald H. Campbell
    • Norman E. Spahr

    OriginalPaper Pages: 415 - 431

11. Use of overlap studies to evaluate method changes in water chemistry protocols

    • Avis D. Newell
    • Marilyn L. Morrison

    OriginalPaper Pages: 433 - 456

12. Testing for trends when there are changes in methods

    • Avis D. Newell
    • D. James Blick
    • Randy C. Hjort

    OriginalPaper Pages: 457 - 468

13. Announcements

    Announcement Pages: 469 - 471