Page 330 - e-Book

inhabiting on the both the sides of the effluent canal and contaminated river accumulated

mercury and cadmium to a significant amount in their body. In the present study the very
presence of heavy metals like mercury and cadmium warrants attention, as these metals were

also found in the plants growing on both the sides of the effluent canal. Our study and
analysis report showed some similarity and trend with the reports of Mishra et al. (2013).

Raina and Agarwal (2003) indicated that the presence of nutrients like N, P, K, Ca, sulphate,
and magnesium in the treated effluents, which were at optimum level, might have

promoted crop growth through enhanced cell division, expansion and differentiation. Our

findings agree with the above workers. However, in the present study we have observed
high suspended solids and dissolved solids along with noticeable amount heavy metal like

mercury and cadmium. The impact of this treated effluent was very heavy on crop plants,

as this contaminated river water is used in the crop fields for irrigation with out final
treatment for removing the suspended solids and heavy metals. Laboratory experimental

study indicated that this effluent can cause harm at higher concentration but if used below
sub-lethal concentration, the effluent will be supportive of growth of the alga. Higher

percentage pigment content decrease in laboratory experimental algae when compared to
field analysis data indicated the interference of environmental parameters and the crop field

soil playing a crucial role for better growth blue-green algae in crop fields. Heavy metals

like mercury and cadmium were absorbed by the tested crop plants and algae showing
adverse effects on the crop plants and algae, as these two metals are dangerously toxic and

can inhibit growth and development of the crop plants which will ultimately influence
production and yield. It was also noticed that the pigment content significantly decreased in

all crop plant leaves growing in the vicinity of the contaminated river. Significant decrease
in pigment content might be due to absorption of heavy metals like mercury and cadmium

which probably inhibited pigment content or destroyed the pigments. This might have

affected the photosynthetic system of the exposed plants thereby influencing the natural
growth but due to availability of nutrients in the effluent, the plants were growing better, side

lining the impact of heavy metals. But in long run, the accumulation of these heavy metals

to a significant amount may finally influence the growth and development of the plants. Our
study clearly indicated that the treated effluent discharged in to natural water body is

toxic and heavy metal rich and changes the physico-chemical status of the natural water
bodies. In our study, it is very clear that the effluent at this status when joins a river can

not be used for irrigation for crop plants without further treatment at industry level

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