Non-parametric Statistical Approach for Assessing the Environmental Impacts of Petroleum Spillages in the Niger Delta Region of Nigeria

Petroleum spillages (PTS) have significantly contributed to environmental degradation in Nigeria’s Niger Delta Region (NDR). This research aims to establish the causes of PTS in the NDR using nonparametric statistical methods for five years. During the five years examined (2019–2023), the recorded number of PTS occurrences was 754 times with 686 cases (90.98%) caused by sabotage and 68 cases (9.02%) due to operational failures. Again, the total PTS recorded during the period is 65,483.27 barrels, and the recovered petroleum resource (PTR) for the five years is 48,262.85 barrels while the unrecovered crude for the period is 17,220.42 barrels. The PTS by sabotage translates to 98.68% while the PTS occasioned by operational failure accounts for only 1.32%. Reportedly, the highest correlation value of 0.999647 and the highest estimated PTS of 24,749.10 barrels with recovered PTS of 22,267.30 barrels were recorded in 2021. Despite recording the highest PTS in 2021, the asymptotic mean integrated squared error (AMISE) shows that 2022 witnessed the toughest environmental conditions for PTS. Therefore, modern pipeline surveillance, community engagement, implementation of legal and economic deterrents for saboteurs, and improvement of infrastructural maintenance to reduce operational failures are recommended steps to reduce sabotage, which is the main cause of PTS in the NDR.