Curious About Water-Quality Science?
Learn more about these topics and how they relate to groundwater quality and surface-water quality and ecology
From chloride to corrosivity, from pesticides to PAHs, find the most recent National Water Quality Program (NWQP) science on these topics and effects on surface water, groundwater, and ecology. Informative web pages provide an overview and links to related web pages, publications, maps, news, and data.
![eDNA sample collection from Alisal Creek, California](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/34480732315_660b417d29_o.jpg?itok=_lrHt6y5)
RELATIONS BETWEEN LAND USE AND WATER QUALITY
Urban
Agricultural
![Macro-invertebrate sampling during SESQA ecological survey](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/13635817564_1d908baaab_z.jpg?itok=P9fu-Wmt)
CONTAMINANTS IN WATER
Arsenic
Chloride and salinity
Emerging contaminants (including pharmaceuticals and hormones)
Mercury
Metals
Nutrients
National Atmospheric Deposition Program (NADP)
Pesticides
Polycyclic aromatic hydrocarbons (PAHs) and coal-tar sealant
Radionuclides
Sediment-associated contaminants
Volatile organic compounds (VOCs), including MTBE
![Water Quality sampling of a public water supply well](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/9846867863_e285df6c76_k.jpg?itok=0Ty059SM)
DRINKING WATER ISSUES
Corrosivity
Domestic (private) supply wells
Public-supply wells
Drinking-water taste and odor
Water-quality benchmarks
Drinking-water and source-water research
RELATIONS TO AQUATIC LIFE
Stream ecology
Mercury in stream ecosystems
Flow alteration
Harmful algal blooms (HABs)
TRENDS IN WATER QUALITY
Water-quality trends
Water-quality trends from lake sediment cores
PROCESSES
Oxidation/Reduction (Redox)
![Line](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/line.png?itok=b8uON6ac)
► Confused by some of the water-quality terms? Find the definitions and explanations you're looking for in the Water-Quality Glossary.
From chloride to corrosivity, from pesticides to PAHs, find the most recent National Water Quality Program (NWQP) science on these topics and effects on surface water, groundwater, and ecology. Informative web pages provide an overview and links to related web pages, publications, maps, news, and data.
![eDNA sample collection from Alisal Creek, California](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/34480732315_660b417d29_o.jpg?itok=_lrHt6y5)
RELATIONS BETWEEN LAND USE AND WATER QUALITY
Urban
Agricultural
![Macro-invertebrate sampling during SESQA ecological survey](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/13635817564_1d908baaab_z.jpg?itok=P9fu-Wmt)
CONTAMINANTS IN WATER
Arsenic
Chloride and salinity
Emerging contaminants (including pharmaceuticals and hormones)
Mercury
Metals
Nutrients
National Atmospheric Deposition Program (NADP)
Pesticides
Polycyclic aromatic hydrocarbons (PAHs) and coal-tar sealant
Radionuclides
Sediment-associated contaminants
Volatile organic compounds (VOCs), including MTBE
![Water Quality sampling of a public water supply well](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/9846867863_e285df6c76_k.jpg?itok=0Ty059SM)
DRINKING WATER ISSUES
Corrosivity
Domestic (private) supply wells
Public-supply wells
Drinking-water taste and odor
Water-quality benchmarks
Drinking-water and source-water research
RELATIONS TO AQUATIC LIFE
Stream ecology
Mercury in stream ecosystems
Flow alteration
Harmful algal blooms (HABs)
TRENDS IN WATER QUALITY
Water-quality trends
Water-quality trends from lake sediment cores
PROCESSES
Oxidation/Reduction (Redox)
![Line](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/line.png?itok=b8uON6ac)
► Confused by some of the water-quality terms? Find the definitions and explanations you're looking for in the Water-Quality Glossary.