Integrated assessment of heavy metal pollution in the great bačka canal: Comparing active and passive sampling methods

This study investigates the environmental risks posed by heavy metals in sediment from the Great Bačka Canal using both active and passive sampling methods. The necessity of this research lies in the critical need to address sediment contamination in ecological hotspots and enhance sediment management practices. Active sampling revealed total heavy metal concentrations, while sequential extraction showed bioavailability varied across metal fractions. Passive sampling with SPeeper™ quantified freely dissolved metal concentrations in sediment pore water, identifying zinc (41 μg/L) as the most bioavailable metal. Risk indices, including I_geo (geo-accumulation index) and IWCTU (interstitial water criteria toxic units), revealed low to moderate contamination levels. Although copper content classified the sediment as extremely polluted (195.7 mg/kg), its low bioavailability (16 μg/L in pore water) mitigates immediate ecological risks. These findings emphasize the importance of integrating passive sampling in regulatory frameworks for a realistic environmental risk assessment of sediments.