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Potential Corrosivity of Untreated Groundwater in Louisiana

Scientific Investigations Report 2024-5035
Prepared in cooperation with the Louisiana Department of Transportation and Development
By:
https://doi.org/10.3133/sir20245035

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Abstract

Corrosive groundwater can cause lead, copper, and other metals to leach from pipes and plumbing fixtures in water distribution systems. Metals, if ingested, could lead to serious health implications to the nearly 2.9 million people in Louisiana who obtain their drinking water from groundwater sources. Four indices—the Langelier Saturation Index (LSI), Ryznar Stability Index (RSI), Puckorius Scaling Index (PSI), and the Potential to Promote Galvanic Corrosion (PPGC)—in addition to an analysis which normalized the results from the existing indices, the Combined Index (CI), were used to assess the corrosivity of groundwater in Louisiana and identify areas within eight major aquifers and aquifer systems with moderate to high corrosivity potential. The purpose of this study is to provide State and local governments, public water system managers, and the nearly 500,000 private well owners in Louisiana with information needed to manage drinking-water supplies and mitigate potential health risks related to leaching of metals from water pipes and fixtures.

The average scores of untreated groundwater samples from approximately 375 wells by index are as follows: LSI, −1.28; RSI, 9.78; PSI, 9.34; and CI, 4.14. The PPGC does not produce a numerical score, but the total percentage of class counts can be used to assign a classification; overall, samples in Louisiana were classified as significant concern. The percentages of groundwater samples from wells classified as potentially corrosive, by index, are as follows: LSI, 53 percent; RSI, 94 percent; PSI, 81 percent; PPGC, 98 percent; and CI, 81 percent. The percentages of samples classified as indeterminate, by index, are as follows: LSI, 46 percent; RSI, 5 percent; PSI, 12 percent; PPGC, 0 percent; and CI, 18 percent.

Suggested Citation

Robinson, A.L., 2024, Potential corrosivity of untreated groundwater in Louisiana: U.S. Geological Survey Scientific Investigations Report 2024–5035, 52 p., https://doi.org/10.3133/sir20245035.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods Used in the Assessment
  • Results and Discussion
  • Summary and Conclusions
  • Acknowledgments
  • References Cited
  • Appendix 1. Other Indices
Publication type Report
Publication Subtype USGS Numbered Series
Title Potential corrosivity of untreated groundwater in Louisiana
Series title Scientific Investigations Report
Series number 2024-5035
DOI 10.3133/sir20245035
Year Published 2024
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Lower Mississippi-Gulf Water Science Center
Description Report: viii, 52 p.; Appendix; 2 Data Releases
Country United States
State Louisiana
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details