| Pesticide residues of Organophosphates (OP) of most commonly used classes were monitored in the water samples collected from agricultural area in various places, Tamil Nadu. The samples were analyzed for DO, COD, BOD, and Phosphate as
test parameters. The data obtained from the laboratory tests were compared based
on the standard or recommended value. The dissolved oxygen level of Bhavani, Coimbatore, Pollachi, and Erode were 3.5mg/L-1
, 3.3mg/L
-1
, 3mg/L
-1
,3.2mg/L-1 showed the significant decrease from the standard value of DO(4-5mg/L-1
), The BOD level of 4 places ( Bhavani, Coimbatore, Erode, Pollachi) are88mg/L
-1
, 105mg/L-1
,93mg/L-1
,142mg/L-1
respectively,showedthe significant variation from
the standard value(1-2mg/L-1
).Same as to BOD , the COD concentration also
significantly varies from the standard value of 1-10mg/L-1
to the highest value of 247mg/L-1
and the lowest value observed as 135mg/L
-1
in the water samples of Bhavani. The standard value of phosphate is 0.5mg/L
-1
, but the result showed that
the phosphate level is more than the recommended concentration in the water samples. Occurrence and concentrations of pesticides residue detected in the water samples by GC-MS. Out of three insecticides namely Methyl parathion, Dichlorvos and Chlorpyrifos only two insecticides were detected except methyl parathion. Insecticides that were present in higher concentrations in the surface water were dichlorvos (4.421µg/mL) in S1 and (1.229 µg/mL) in S4, where as in S3
chlorpyrifos was detected (1.329 µg/mL) except methyl parathion in S2. This could be due to frequent usage of the above mentioned insecticides plus contamination
could originate from the application sites. |