Bioremediation of contaminated land and water uses living organisms including microbes, plants, and sometimes animals to clean pollutants, with variable welfare implications.
Bioremediation welfare is complex because the animals involved — oysters, earthworms, fish — interact with the contaminants being remediated in ways that may compromise their welfare. Oysters used for water filtration in contaminated areas accumulate heavy metals and organic pollutants that affect their physiology. Earthworms in contaminated soil bioremediation experience toxin exposure that may cause chronic welfare harm. The welfare calculus requires comparing the harm to individual remediation organisms against the benefit to the broader ecosystem and the animal communities that will inhabit the restored environment. Welfare monitoring of bioremediation animals should be standard practice in project design.