Why is nitrite so toxic

Changes in oxygen affinity and blood pH increase the movement of oxygen to the swim bladder. This can lead to buoyancy problems. Diagnosis relies on the measurement of nitrite levels in the system or tank water, and some gross evidence of methaemaglobinaemia.

Toxicity levels vary between species of fish, but it is preferable to keep levels as low as possible in all cases. Nitrite is much less toxic when chloride is present, possibly because chloride inhibits nitrite absorption across the gills. Haemaglobin levels should return to normal within hours. If severe anaemia is present, recovery may take weeks. The original cause of the nitrite toxicity should be resolved. Levels of nitrite in the water can be reduced through water changes, biological filtration and decreased feeding.

Prevention involves ensuring an adequate level of chloride in the water at all times. People can become nitrite-poisoned in many different ways. Misuse or excessive use of any medicine or product containing nitrates, whether unintentionally or intentionally, can lead to poisoning.

Poisoning can result from swallowing, inhaling, or even skin contact. People have been poisoned after drinking nitrate-contaminated rural well water. This occurs in agricultural areas using nitrogen-based fertilizers. Fertilizer run-off can contaminate nearby wells that are shallow or poorly constructed. In the past, some infants who were fed formula prepared with nitrate-contaminated well water died from severe methemoglobinemia. Symptoms of nitrate poisoning can vary depending on the amount and duration of the exposure.

Those with very mild methemoglobinemia might not have any symptoms at all, or might appear a little pale and feel tired. Moderate-to-severe poisoning is associated with cyanosis blueness of the skin , confusion, loss of consciousness, seizures, abnormal heart rhythms, and death. The old toxicology adage by the 16 th century physician Paracelsus, "the dose makes the poison," truly applies to nitrates and nitrites.

No living thing can live and grow without them, but too much can be deadly. Call or. A year-old man suddenly became nauseated and vomited during a business meeting. When an ambulance brought him to an ER, his skin was described as navy blue. He was awake and alert, but the oxygen content of his blood was low. He mentioned that he had mixed two chemicals while at work just before the meeting.

He had inadvertently inhaled the liquid and had also gotten some on his skin. One of the two chemicals was sodium nitrate. Diseases and contaminants: nitrate and drinking water from private wells. Atlanta GA; [accessed Nov 30, ]. ToxFAQs for nitrate and nitrite. A severe methaemoglobinemia induced by nitrates: a case report.

However, in new aquariums where the bacteria population hasn't grown adequately to detoxify the wastes from the fish in the aquarium, ammonia can build up to toxic levels quickly. Nitrite poisoning follows closely on the heels of elevated ammonia as a major killer of aquarium fish.

Anytime ammonia levels are elevated, elevated nitrite will soon follow. To avoid nitrite poisoning, test the water when setting up a new tank , when adding new fish to an established tank, when the filter fails due to power or mechanical failure, and when medicating sick fish. Nitrite poisoning is also known as "brown blood disease" because the blood turns brown from an increase of methemoglobin.

However, methemoglobin causes a more serious problem than just changing the color of the blood. It renders the blood unable to carry oxygen, and the fish can literally suffocate even though there is ample oxygen present in the water.

Different species of fish tolerate different levels of nitrite. Some fish may simply be listless, while others may die suddenly with no obvious signs of illness. Common symptoms include gasping at the surface of the water, hanging near water outlets, rapid gill movement, and a change in gill color from the normal pink to dark brown. Fish that are exposed to even low levels of nitrite for long periods of time suffer damage to their immune system and are prone to secondary diseases, such as ich , fin rot , and bacterial infections.

First, perform water changes with dechlorinated water to reduce the nitrite level. The addition of a half-ounce 1 tablespoon of salt per gallon of water will prevent methemoglobin toxicity by blocking the nitrite absorption through the fish's gills. Any aquarium salt or marine salt mix can be used. Do not use iodized table salt. Aeration should be increased to provide ample oxygen saturation in the water.

Feedings should be reduced and no new fish should be added to the tank until the ammonia and nitrite levels have fallen to zero. That will reduce the formation of excess ammonia, which will be converted to nitrite. It is critical to continue daily testing and treatment until the nitrite level falls to zero. The key to eliminating fish death is to avoid extreme spikes and prolonged elevation of nitrite.

When starting a new tank, add only a couple of fish initially and do not add more until the tank is completely cycled.