Newt
Newts, as with salamanders in general and other amphibians, serve as bioindicators because of their thin, sensitive skin and evidence of their presence (or absence) can serve as an indicator of the health of the environment. Most species are highly sensitive to subtle changes in the pH level of the streams and lakes where they live. Because their skin is permeable to water, they absorb oxygen and other substances they need through their skin. Scientists study the stability of the amphibian population when studying the water quality of a particular body of water.
Italian crested newt
Nonylphenol is a large issue for "T. carnifex" because it is a very common toxin found in leakage from sewers into the habitat of the Italian crested newt. Newts are amphibians, and make their habitats in aquatic environments. These environments have been known to sometimes receive the previously discussed sewage leaking. The compounds nonylphenol as well as ethoxylate surfactants can be found in polluted rivers, where the newts reside. The two substances discussed can be transformed, by microorganisms, into compounds which are much more toxic. They are extremely good bioindicators, due to the magnification of these chemicals in the environment demonstrated in the newt. Nonylphenol absorbed through the newts’ skin is especially dangerous because it can result in issues with the reproductive biology as well as cutaneous and osmoregulatory mechanisms.