Activities of idol immersion leads to heavy metal contamination in river Hooghly in and around the city of Kolkata

West Bengal is a rich cultural state for a number of religious festivals. One of the most important festival is Kali Puja and Diwali. Idol is supposed to be the image of God which is used for worship. After worshiping immersion of idols took place in the various Ghats of the river. Several accessories of worship such as flowers, food offerings, plastic sheets, polythene bags etc. are also poured in water. Materials of idols consist of clay, plaster of Paris, varnish, oil paint etc. These paints are highly pigmented and consist of white lead, lithopone, chrome yellow, cadmium sulphide, barium chromate, vermillion, red lead etc. heavy metal salts. This study is an attempt to assess the change in water quality before and after the immersion of idols giving emphasis on heavy metal. The above investigation were carried out by collecting the water samples from six immersion ghats of the river Hooghly before & after immersion of Kali idols of the year 2019 followed by the analysis of the different parameters of water. Investigation reveals a significant changes in heavy metal concentration between pre and post immersion of the idols. A pollution due to the idols immersion into the water bodies cause adverse effect to the aquatic life or entire ecosystem.Use of natural dyes for idols obtained from flowers, leaves roots of plants, wood, seeds may reduce this pollution to a significant level. Moreover, awareness among the people of the society may have a significant responsibility in controlling this pollution satisfactorily.