Assessment biodegradation of chlorinated pesticides by isolated bacteria (Pseudomonas species) from the Mazandaran Rivers

Organochlorine pesticides are as environmental pollutants which have a high half-life and transmit from food chain to human and cause side effects such as mutations in different genes and finally cancer. In this research، after sampling and quantitative and qualitative of organochlorine residue، biodegradation of alpha، beta and gamma hexachlorobenzene (Linden)، DDT، Aldrin، Dieldrin، Endosulfan، Endrin and Heptachlor by three species of pseudomonas (aeruginosa، fluorescence، putida) isolated of Mazandaran Rivers (Tajan، Babolrood and Shiroud) was studied at laboratory scale. After adaptation of the three species of psuedomonas in mineral medium، 5% of the mixture culture was added to the medium containing 30 mg l of mixture pesticides. Changes of bacterial growth and pesticides concentration in zero، 24، 48، 54 and 120 hours were determined by observation of optical density (spectrophotometer) and gas chromatography respectively. The results showed that the highest biodegradation of pesticides was referred to DDT and Lindane، so that concentration of two pectisides was 9. 54 and 9. 3 after 120 hours respectively. The lowest biodegradation of pesticides was referred to endrine and it،s concenteration in 120 hours 13. 45 mg l. The maximum absorbance of bacteria were observed in 48 hours. The conclusion showed that pseudomonase has high potencial for organochlorine pecticides biodegradation especially DDT and lindane in bench scale and can be used different species of pseudomonase in full scale for decreasing of organochlorine.