Assessment of heavy metal enrichment, ecological risk with in-situ phyco-remediation approach: A regional study from Odisha's coastal creeks, India

Abstract

Increasingly, coastal creeks are vulnerable to heavy metal (HM) pollution, while their ecological risks and remediation potential remain poorly understood. This work investigated HM pollution, ecological risks, and bioaccumulation potential of indigenous marine macroalgae (seaweed), Chaetomorpha linum, in two contrasting creeks, Jatadhar Muhan Creek (JMC) and Haripur Creek (HC), along Odisha's coast, India. Accumulation potential was assessed using geochemical indices, including enrichment factor (EF), contamination factor (CF), geo-accumulation index (Igeo), pollution load index (PLI), ecological risk factor (E-r(i)), and potential ecological risk index (PERI), while CCME and NOAA sediment quality guidelines were employed to evaluate ecological risks. Most studied elements showed low to moderate levels of pollution, with significant enrichments and high ecological risks mainly caused by Cd and Pb. The dominant element, Cd, ranged from moderate to extreme pollution (2.35 <= Igeo <= 6.62) with very high enrichments (EF up to 1311.3) at HC. Although PLI values (<1) indicated low pollution, elevated EF and Cdeg values indicated anthropogenic stress. Field observations documented naturally abundant seaweed and bioaccumulation metrics (BAF, MAI) to determine the uptake efficiency of bioavailable metals under ambient conditions. The presence of C. linum with high metal uptake capacity suggests its potential as a passive, nature-based solution. These region-specific findings support integrating ecological risk assessment (ERA) with biological indicators for sustainable management of tropical coastal creeks.