Heavy metal monitoring and health risk assessment of a tropical mountainous river in Kerala, India

Abstract

ABSTRACTSeasonal monitoring of surface water was performed in Meenachil River with emphasis on heavy metal quality. Mean concentration of heavy metals such as Cu, Cr, Zn and Pb during post-monsoon are comparatively higher than that in the other seasons. As and Cd concentrations are below detectable limit in all seasons. The escalated heavy metal pollution index (HPI) and contamination degree (CD) index level at the river mouth indicate a contaminated environment. Direct application of agrochemicals in the typical catchment activities like intense plantation and widespread lowland agriculture contribute heavy metals to the riverine system. The contamination index (CI) was strongly lowered during monsoon. The study has demonstrated that the mean hazard quotient falls to a permissible level throughout pre-monsoon and monsoon while the level slightly exceeds the level during post-monsoon. HPI, CD and CI indices suggest that better agricultural management practices need to be implemented in the Meenachil River basin for maintaining ecological integrity and protecting the lotic system from further degradation.