---
title: Sulfates
description: "## Summary Sulfate is a byproduct of pyrite oxidation and is commonly elevated in AMD-impacted streams. This page explains how sulfates relate to AMD, what sulfate levels indicate, and how they are measured. --- Sulfates enter a stream by erosion.…"
url: "https://aml-connect.org/aml-knowledge-base/chemical-monitoring-sulfates/"
updated: "2026-03-13"
category: Watershed Tools and Methods / Water Monitoring / Chemical Monitoring
---

# Sulfates

## Summary

Sulfate is a byproduct of pyrite oxidation and is commonly elevated in AMD-impacted streams. This page explains how sulfates relate to AMD, what sulfate levels indicate, and how they are measured.

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Sulfates enter a stream by erosion. Areas with high concentrations of gypsum or shale are prone to high sulfate concentrations. AMD also adds large amounts of sulfates to the water. Iron pyrite (FeS2), a large element of AMD, yields both ferrous iron and sulfate when flowing into streams.

Other tests, including and/or in addition to those described above, may be appropriate for the watershed in your area. The indicators the were chosen as points of study while making your monitoring plan are a good way to decide what tests need to be performed.

**Sources/Links (as provided in the source text):**

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## Related Pages

- [Developing a Monitoring Plan](/docs/developing-a-monitoring-plan) -- Structuring your monitoring program
- [Introduction to AMD Chemistry](/docs/introduction-to-amd-chemistry)

## Source and Last Reviewed

Source: AMR Clearinghouse (amrclearinghouse.org). Migrated to AML-Connect. Last Reviewed: 2026-03-13.

**Tags:** amd, monitoring, sampling