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4.2 Analysis of Soil Profiles

Soil collected from the three different locations were analysed and the following observations
were made.

Table 3 . Soil Profiles collected from three different locations.
Soil pH ranged from 4.9 to 5.6 indicating alkaline nature. This was in contrast to the post

flood studies analysed at the CTCRI laboratory, Trivandrum, from all districts indicated soil
pH of below 3.5, indicating abnormally high acidity, in a sandy deposit in Vijayapuram

grama panchayat in Kottayam district.

The organic carbon content of the samples studied ranged from 0.75 to 2.22% in these areas,
whereas according to the study by CTCRI, 0.06 to 4.55% and a very high value of 4.55% was

recorded in a sample collected from Kasaragod district (https://www.thehindu.com/ news/

national/ kerala/ soil-quality-affected-by-floods-says-study/ article 25570720. ece).
Analysis of major, secondary and micronutrients indicated changes in soil chemistry.

Potassium levels ranged from 170-471, whereas Phosphorous levels were ranging from 9.24
to 29.82 kg/ha. This may be indicative of the better soil drainage conditions in these areas in

contrast to the CTCRI studies, wherein one of the samples collected from Neyyattinkara
municipality, the available phosphorus content was to the tune of 755.87 kg a hectare, which

is extremely toxic for crop cultivation. The soil samples collected from interior zones of

Kannadikal shower\d high variations from the peripheral zones, indicating the impact of a
proper drainage and outflow of water and other residuals.

4.3 Identification of plants in Phytoremediation
Three plant species viz. Wedelia trilobata (entire plant - with complete root and shoot

system) , Moringa oleifera (stem cuttings,) and Brassica nigra - seedlings were considered to
analyse its potential in restoring and withstanding toxicity in the environment especially in

the post flood scenario.

4.3.1 Effect of plant species in phytoremediation of Mercury (HgCl2)
Concentration Hourly observations
% After
1hr 2hr 3hr 5hr 24hr 30hr 48hr 72hr 96hr 120hr
Wedelia trilobata
0.01 NC NC NC NC NC Wilting Leaves are Plant
started dry and completel
dead y dry and
dead
0.05 NC NC NC Slight Wilting Yellowing Plant
wilting , burning completely

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