Temporal Change in The Ecological Risk Level of The Havran Lagoon (Balikesir)

Abstract

The Havran Lagoon is formed at the mouth of the Havran Stream in the Havran district of Balikesir, located on the Aegean Sea coast. This study aimed to investigate the ecological effects of element pollution on the lagoon caused by rapidly increasing anthropogenic activities in the region. In this context, 34 cm-long core was taken from the Havran Lagoon, and then to determine their role in the transport processes of the elements, chlorophyll degradation products and total organic carbon analysis were performed. Element concentration analyzes were performed with ICP-MS at the Bureau Veritas Analytical Laboratory (Canada). Element sources were identified with the help of the enrichment factor and geo-accumulation index. The toxic risk index, ecological risk index, and potential ecological risk index were used for ecological risk assessment. According to the findings obtained from enrichment factor, Mo, Ti, Mn and Cd were found to be moderately enriched, while As was significantly enriched in different parts of the core. Hence, it was confirmed that the mentioned elements were affected by anthropogenic activities. According to the results of the principal component analysis, Mo, Cu, Mn, Cd, Zn, Ni, and Hg and Cu, Pb, and As appear to have common sources. The toxic risk reached a moderate level due to high As contamination in the lower parts of the core, but decreased to a low level at the surface. Hg and As produced a moderate ecological risk, while Cd was associated with a moderate to significant ecological risk. There is a moderate potential ecological risk in the lagoon. The increasing concentration of organic carbon and chlorophyll degradation products in recent years indicates organic pollution. The dominant anthropogenic activities were identified to be agriculture, industry, and settlement during the resource definition of the elements.