Carbaryl is an insecticide (marketed as Sevin®) used on a wide range of crops, home gardens, lawns, and trees. According to the WHO, it's also used in “public health and veterinary practice.”
The main source of human carbaryl ingestion is through food; it dissipates from water within a month or less and is yet to be reported in drinking water, though it could potentially arrive through over-spraying or spillage from its insecticidal use.
Carbaryl is a neurotoxin, inhibiting the enzyme cholinesterase and leading to symptoms of irritation, nausea, vomiting, difficulty breathing, blurred vision, convulsions, and coma with acute exposure.
Long term exposure has been shown to cause headaches, memory loss, muscle weakness and cramps, and can potentially lead to kidney or liver damage. It is not believed to be carcinogenic.
Carbaryl can be treated effectively with activated carbon, removing 99%. Other treatment methods include coagulation and ozonation.
(whole house & well units)