Copper(II) nitrate is a nitrate of copper. Copper is a chemical element with the symbol Cu and atomic number 29. Copper is an essential elements in plants and animals as it is required for the normal functioning of more than 30 enzymes. It occurs naturally throughout the environment in rocks, soil, water, and air. Nitrite is a toxic compound known to cause methemoglobinemia. (11, 7, 8)
belongs to the class of inorganic compounds known as transition metal nitrates. These are inorganic compounds in which the largest oxoanion is nitrate, and in which the heaviest atom not in an oxoanion is a transition metal.
Excess copper is sequestered within hepatocyte lysosomes, where it is complexed with metallothionein. Copper hepatotoxicity is believed to occur when the lysosomes become saturated and copper accumulates in the nucleus, causing nuclear damage. This damage is possibly a result of oxidative damage, including lipid peroxidation. Copper inhibits the sulfhydryl group enzymes such as glucose-6-phosphate 1-dehydrogenase, glutathione reductase, and paraoxonases, which protect the cell from free oxygen radicals. It also influences gene expression and is a co-factor for oxidative enzymes such as cytochrome C oxidase and lysyl oxidase. In addition, the oxidative stress induced by copper is thought to activate acid sphingomyelinase, which lead to the production of ceramide, an apoptotic signal, as well as cause hemolytic anemia. Copper-induced emesis results from stimulation of the vagus nerve. Nitrate's toxicity is a result of it's conversion to nitrite once in the body. Nitrite causes the autocatalytic oxidation of oxyhemoglobin to hydrogen peroxide and methemoglobin. This elevation of methemoglobin levels is a condition known as methemoglobinemia, and is characterized by tissue hypoxia, as methemoglobin cannot bind oxygen. (3, 12, 7, 14, 1, 10)
Metabolism
Copper is mainly absorbed through the gastrointestinal tract, but it can also be inhalated and absorbed dermally. It passes through the basolateral membrane, possibly via regulatory copper transporters, and is transported to the liver and kidney bound to serum albumin. The liver is the critical organ for copper homoeostasis. In the liver and other tissues, copper is stored bound to metallothionein, amino acids, and in association with copper-dependent enzymes, then partitioned for excretion through the bile or incorporation into intra- and extracellular proteins. The transport of copper to the peripheral tissues is accomplished through the plasma attached to serum albumin, ceruloplasmin or low-molecular-weight complexes. Copper may induce the production of metallothionein and ceruloplasmin. The membrane-bound copper transporting adenosine triphosphatase (Cu-ATPase) transports copper ions into and out of cells. Physiologically normal levels of copper in the body are held constant by alterations in the rate and amount of copper absorption, compartmental distribution, and excretion. Intake of some amount of nitrates and nitrites is a normal part of the nitrogen cycle in humans. In vivo conversion of nitrates to nitrites can occur in the gastrointestional tract under the right conditions, significantly enhancing nitrates' toxic potency. The major metabolic pathway for nitrate is conversion to nitrite, and then to ammonia. Nitrites, nitrates, and their metabolites are excreted in the urine. (11, 7, 9)
Toxicity Values
Not Available
Lethal Dose
10 to 20 grams for an adult human (copper salts). (13)
People must absorb small amounts of copper every day because copper is essential for good health, however, high levels of copper can be harmful. Very-high doses of copper can cause damage to your liver and kidneys, and can even cause death. Copper may induce allergic responses in sensitive individuals. Nitrate and nitrite poisoning causes methemoglobinemia. Nitrites may cause pregnancy complications and developmental effects. They may also be carcinogenic. (11, 8, 9)
Symptoms
Breathing high levels of copper can cause irritation of the nose and throat. Ingesting high levels of copper can cause nausea, vomiting, diarrhea, headache, dizziness, and respiratory difficulty. Nitrate and nitrite poisoning causes methemoglobinemia. Symptoms include cyanosis, cardiac dysrhythmias and circulatory failure, and progressive central nervous system (CNS) effects. CNS effects can range from mild dizziness and lethargy to coma and convulsions. (11, 8, 9)
Treatment
Methemoglobinemia can be treated with supplemental oxygen and methylene blue 1% solution administered intravenously slowly over five minutes followed by IV flush with normal saline. Methylene blue restores the iron in hemoglobin to its normal (reduced) oxygen-carrying state. (12)
