Three test tubes with filter paper inside
![Three test tubes with filter paper inside](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/filter_tubs_from_iron_nitrate_test_smith_dscn0656_l.jpg?itok=_PqeGOpp)
Detailed Description
Photograph of iron(III) oxyhydroxides (yellow-brown color in two left-hand tubes collected on folded filter paper) that was produced in iron(II)-containing groundwater by the addition of nitrate. The tube on the right is a filter collected from the same groundwater before nitrate was added.
Sources/Usage
Public Domain.