Ecotoxicological implications of agricultural ecosystem sedimentary arsenic exposure in benthic organisms: A case study on apple snail

Arsenic (As), a metalloid widely distributed in the environment, remains underexplored regarding its ecotoxicological effects on benthic organisms, especially those exposed to agricultural ecosystem sedimentary As. This study systematically explored the toxicological effects of agricultural ecosystem sedimentary As on the benthic apple snail ( Pomacea canaliculata ) by combining field sampling and laboratory research. Field sampling surveys showed that the correlation between benthic animal tissues and sediments was stronger than that with water samples. Subsequently, we conducted an indoor study on the ecotoxicological effects of sediments on the benthic animal apple snail. Using physiologically based pharmacokinetic (PBPK) modeling and bioaccumulation analysis, we demonstrated that sedimentary As exhibited significantly higher bioaccumulation potential compared with sediment leachate. The highest total As concentration was detected in the shell (3.08 μg g −1 ), followed by the intestine-stomach (0.75 μg g −1 ), visceral mass (0.70 μg g −1 ), and head-foot (0.33 μg g −1 ). The visceral mass played a critical role in As metabolism, while the head-foot primarily facilitated As transport, and the shell served as the main storage site. Sedimentary As exposure triggered severe oxidative stress in the intestine-stomach and liver, leading to pronounced damage to the intestinal microvilli, including atrophy, degeneration, and apoptosis. Additionally, sediment exposure significantly increased the diversity of gut microbiota and altered the expression of genes associated with gut microbial function. • Sediment As is the primary source of As in benthic organism tissues. • Sedimentary As induces oxidative stress and intestinal damage in benthic organisms. • Sediment As increases the abundance of gut microbiota in benthic organisms. • The ecotoxicological effects of sediment pollution on benthic organisms are overlooked.