Main sources of sulphur are its oxides in the environment due to the burning of fossil fuels and volcanic emissions through vehicles, industry processes etc.
Soil, water and rocks containing sulphates, sulphides and organic sulphur, and also body of living organisms. High concentrations of suphur oxides forms acid which is found in acid rain.
Also sulphur is found from body of living organisms, water, soil, rocks containing sulphides, organic sulphur, sulphates etc.
There are several refineries who produce large quantity of sulphur. Ilam, Bidboland, Hsheminejad and south pars are some important gas refineries produces tons of sulphur.
Elemental Sulphur from Nature
In volcanic areas, gases like H2S and SO2 often reacts and store elemental sulphur. Such sources exist in Sicily, Japan and South America. Also there are biogenic sources of elemental sulphur. Suphur is produced by processing the gypsum and anyhdrite stores by anaerobic bacteria. This processing reduces the sulphate to sulphur and also produce H2S and CO2 as by-products.
Sulphur is also found n many food sources, some of them are as follows-
Amino acids - Methionine, Cystine, Cysteine and lysine