Investigation of Seasonal Shifts in Water Quality and Index Assessment of Chakkamkandam Lake, Kerala, India

Abstract

Lakes play a crucial role in supporting ecological balance by regulating river discharge and serving as essential freshwater reserves, especially during dry periods. Ensuring the health of these aquatic systems is vital for sustainable water resource management. In Kerala, India, many lakes are increasingly threatened by human-induced stress, particularly from the continuous inflow of domestic wastewater and agricultural runoff, which significantly alter water chemistry. This study focuses on assessing the seasonal variation in water quality and calculating the Water Quality Index (WQI) of Chakkamkandam Lake in Kerala. Water samples were collected from four different sites over three distinct seasons—pre-monsoon, monsoon, and post-monsoon—between October 2019 and September 2020. Standard analytical methods were employed to measure various physicochemical parameters, along with concentrations of heavy metals such as lead, cadmium, iron, and chromium. The WQI was determined using the weighted arithmetic mean method. Results indicated that most water quality parameters exceeded acceptable standards, except for pH, nitrate, and fluoride. Notably, the highest levels of organic pollutants and heavy metals were recorded during the pre- and post-monsoon seasons. The WQI scores—1693.7 (pre-monsoon), 235.8 (monsoon), and 389.3 (post-monsoon)—classified the lake’s water quality as “very poor” across all seasons. These findings highlight the significant impact of industrial, agricultural, residential, and tourism-related activities on the lake’s ecosystem. The study emphasizes the urgent need for continuous water quality monitoring and the implementation of stringent environmental regulations. It provides valuable insights for local authorities, researchers, and public health stakeholders globally.