Oxalic acid binds with calcium to form calcium oxalate crystals which may deposit and cause damage to many areas of the body including the brain, heart, kidneys, and lungs. The most significant effect is accumulation of calcium oxalate crystals in the kidneys which causes kidney damage leading to oliguric or anuric acute kidney failure. The rate-limiting step in this cascade is the conversion of glycolic to glyoxylic acid. Accumulation of glycolic acid in the body is mainly responsible for toxicity. Toxicity
Ethylene glycol has been shown to be toxic to humans and is also toxic to domestic pets such as cats and dogs. A toxic dose requiring medical treatment varies but is considered more than 0.1 mL per kg body weight (mL/kg) of pure substance. That is roughly 16 mL of 50% ethylene glycol for an 80 kg adult and 4 mL for a 20 kg child. Poison control centers often use more than a lick or taste in a child or more than a mouthful in an adult as a dose requiring hospital assessment.The orally lethal dose in humans has been reported as approximately 1.4 mL/kg of pure ethylene glycol. That is approximately 224 mL (7.6 oz.) of 50% ethylene glycol for an 80 kg adult and 56 mL (2 oz.) for a 20 kg child. Although survival with medical treatment has occurred with doses much higher than this, death has occurred with 30 mL of the concentrate in an adult.
If untreated, death most commonly occurs during this period. Stage 3 (24 to 72 hours) kidney failure is the result of ethylene glycol poisoning. In cats, this stage occurs 12–24 hours after consuming antifreeze; in dogs, at 36–72 hours after consuming antifreeze. During this stage, severe kidney failure is developing secondary to calcium oxalate crystals forming in the kidneys. Severe lethargy, coma, depression, vomiting, seizures, drooling, and inappetence may be seen. Other symptoms include acute tubular necrosis, red blood cells in the urine, excess proteins in the urine, lower back pain, decreased or absent production of urine, elevated blood concentration of potassium, and acute kidney failure. If kidney failure occurs it is typically reversible, although weeks or months of supportive care including hemodialysis may be required before kidney function returns. Sources
The most common source of ethylene glycol is automotive antifreeze or radiator coolant, where concentrations are high. Other sources of ethylene glycol include windshield deicing agents, brake fluid, motor oil, developing solutions for hobby photographers, wood stains, solvents, and paints. Some people put antifreeze into their cabins toilet to prevent it from freezing during the winter, resulting in toxicities when animals drink from the toilet. Small amounts of ethylene glycol may be contained in holiday ornaments such as snow globes.The most significant source of ethylene glycol is from aircraft de-icing and anti-icing operations, where it is released onto land and eventually to waterways near airports experiencing cold winter climates. It is also used in manufacturing polyester products.