There are two sources of molybdenum in the environment
1. Weathering releases molybdenum from rocks. It is estimated that 1000 tons enter the water and soil every year and migrate in the environment. The non-uniformity of molybdenum distribution results in the lack of molybdenum in some areas and the occurrence of "water and soil diseases"; in some areas, the high molybdenum content causes the occurrence of "gout disease" (such as Armenia).
2. Molybdenum is more and more widely used in human activities and the combustion of molybdenum containing fossil fuels (such as coal) increases the circulation of molybdenum in the environment. The world's Molybdenum output is 100000 tons per year, and the amount of molybdenum burned into the environment is 800 tons per year. Human activities add more cycles than natural ones. More molybdenum is used in metallurgy, electronics, missiles, aerospace, atomic energy, chemical industry and agriculture. The study of molybdenum pollution is not enough.
The migration of molybdenum in the environment is related to the oxidation and reduction conditions, pH and other media. The higher the oxidizability of water and soil, the higher the basicity, the easier Mo is to form Mo O ~ (?); plants can absorb Mo in this state. With the increase of acidity or reducibility of environment, molybdenum is easily converted into complex ions, and then moo is formed; molybdenum in this state is easily fixed by clay, soil colloid and humic acid and loses its activity, so it cannot be absorbed by plants. In the ocean, the reduction environment in the deep sea makes molybdenum adsorbed by organic matter and wrapped in the colloid containing manganese. Later, the nodule forms and sinks on the sea floor, leaving the biosphere cycle.
Molybdenum has little effect on warm blooded animals and fish. High content of molybdenum has adverse effects on plants. The results show that when the concentration of molybdenum is 0.5-100 mg / L, it will have different effects on the growth of flax; when the concentration is 10-20 mg / L, it will do harm to the growth of soybean; when the concentration is 25-35 mg / L, it will do harm to the growth of cotton; when the concentration is 40 mg / L, it will do harm to the growth of sugar beet. When the concentration of molybdenum in water reaches 5mg / L, the biological self purification of water body will be inhibited; when 10mg / L, the effect will be more inhibited, and the water will have strong astringency; when 100mg / L, the growth of water microorganism will slow down, and the water will have bitter taste. China stipulates that the higher allowable concentration of molybdenum in ground water is 0.5mg/l, the higher allowable concentration of soluble molybdenum in the air of workshop is 4mg / m3, and the insoluble molybdenum is 6mg / m3.