492
K.S. Patel et al.
ponds, and 10 different river basins of central India (Fig. 1). The colour of the
surface water and sediments was recorded (Table 2). The pH of the water at the
site was measured. At all sampling sites the pond sediments were clayey, whereas
the river sediments were sandy. The water samples were filtered through
Whatman filter paper no. 42. The wet sediment samples were sieved through a
500-~Lm mesh sieve and stored in a polyethylene bag. The sediment samples were
oven-dried at 60 DC for 48 h.
3
Procedure for Determination of Heavy Metals
Five grams of dried and weighed sediment samples were transferred into a 250ml conical flask and treated with 3 ml each of concentrated H2S0 4 and HN0 3
acids and 1 ml of concentrated HCI0 4 acid at 4 DC. The conical flask was stored
for 1 week after closing the mouth with a stopper. The extract was filtered with
Whatman filter paper no. 42 by washing with the HN0 3 acid (0.1 M) and diluted
to 50 ml with deionized double distilled water. The heavy metals in the extract
were monitored by AAS techniques, i.e. acetylene flame, graphite furnace, cold
vapour AAS using calibration curves prepared under similar conditions
(Table 1).
4
Procedure for Determination of Hg in Water Samples
Ten ml of the filtered water sample was taken in a 50-ml beaker and the labile Hg
(the inorganic species reducible with borohydride) was determined by cold
vapour AAS. Total Hg (the inorganic plus the organic) was determined by
treating 10 ml of the filtered water sample with 0.5 ml KMn04 solution and
waiting for at least 6 h at room temperature (20 ± 2 DC) for complete liberation
of the non-labile Hg (organic mercury). The total Hg content was determined by
cold vapour AAS as above.
5
Results and Discussion
5.1
Mercury in Water
The maximum temperature of surface water during day in the 1st week of June
was 40 ± 3 DC. All surface waters except some river waters were coloured. The
pH of the surface water ranged between 6.1 and 9. The concentrations of the
K.S. Patel et al.
ponds, and 10 different river basins of central India (Fig. 1). The colour of the
surface water and sediments was recorded (Table 2). The pH of the water at the
site was measured. At all sampling sites the pond sediments were clayey, whereas
the river sediments were sandy. The water samples were filtered through
Whatman filter paper no. 42. The wet sediment samples were sieved through a
500-~Lm mesh sieve and stored in a polyethylene bag. The sediment samples were
oven-dried at 60 DC for 48 h.
3
Procedure for Determination of Heavy Metals
Five grams of dried and weighed sediment samples were transferred into a 250ml conical flask and treated with 3 ml each of concentrated H2S0 4 and HN0 3
acids and 1 ml of concentrated HCI0 4 acid at 4 DC. The conical flask was stored
for 1 week after closing the mouth with a stopper. The extract was filtered with
Whatman filter paper no. 42 by washing with the HN0 3 acid (0.1 M) and diluted
to 50 ml with deionized double distilled water. The heavy metals in the extract
were monitored by AAS techniques, i.e. acetylene flame, graphite furnace, cold
vapour AAS using calibration curves prepared under similar conditions
(Table 1).
4
Procedure for Determination of Hg in Water Samples
Ten ml of the filtered water sample was taken in a 50-ml beaker and the labile Hg
(the inorganic species reducible with borohydride) was determined by cold
vapour AAS. Total Hg (the inorganic plus the organic) was determined by
treating 10 ml of the filtered water sample with 0.5 ml KMn04 solution and
waiting for at least 6 h at room temperature (20 ± 2 DC) for complete liberation
of the non-labile Hg (organic mercury). The total Hg content was determined by
cold vapour AAS as above.
5
Results and Discussion
5.1
Mercury in Water
The maximum temperature of surface water during day in the 1st week of June
was 40 ± 3 DC. All surface waters except some river waters were coloured. The
pH of the surface water ranged between 6.1 and 9. The concentrations of the