Newt
During the subsequent few months, the larvae undergo metamorphosis, during which they develop legs, and the gills are absorbed and replaced by air-breathing lungs. Some species, such as the North American newts, also become more brightly coloured during this phase. Once fully metamorphosised, they leave the water and live a terrestrial life, when they are known as "efts". Only when the eft reaches adulthood will the North American species return to live in water, rarely venturing back onto the land. Conversely, most European species live their adult lives on land and only visit water to breed.
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.