Decomposition Chemistry and Postmortem Interval Estimation in Tropical Riverine Environments: A Study in Bayelsa State

The estimation of postmortem intervals in aquatic and riverine environments is complicated by environmental variables including water temperature, current dynamics, and microbial ecology that differ significantly from terrestrial contexts. This study investigates decomposition chemistry and postmortem interval estimation in tropical riverine environments using controlled experimental and casework data from Bayelsa State, South South Nigeria. An empirical experimental design was employed, involving the placement of porcine proxy specimens in controlled riverine conditions at three ecologically distinct water bodies in the Niger Delta, with systematic monitoring of decomposition stage progression, adipocere formation, and water temperature profiles over ninety-day periods. Findings were validated against postmortem interval estimates in twelve confirmed drowning and aquatic recovery cases from Bayelsa State Police forensic records. Results indicate that adipocere formation, a saponification process of body fat, occurs at significantly accelerated rates in the warm, slow-moving waters of the Niger Delta compared to temperate reference data, with full saponification observed within fourteen to twenty-one days. Standard terrestrial accumulated degree day models overestimated postmortem intervals by an average of thirty-one percent when applied to the aquatic cases. The study proposes a region-specific aquatic postmortem interval estimation model incorporating Niger Delta temperature and current parameters. Recommendations include field validation of the proposed model and training of forensic pathologists in aquatic taphonomy. Keywords: decomposition, postmortem interval, riverine environment, Bayelsa State, adipocere.