Spatial Pattern Assessment and Prediction of Water and Sedimentary Mud Quality Changes in Lake Maurepas

Lake Maurepas, Louisiana, holds ecological, recreational, and economic significance, but recent concerns have arisen over its water quality due to industrial activities. From June to November 2023, we investigated water and sediment quality at nine sites and three depths. Results showed that NH3-N levels were within safety limits (0.11 ± 0.10 mg/L), while Total Nitrogen (TN, 0.83 ± 0.65 mg/L), Total Phosphorus (TP, 0.32 ± 0.13 mg/L), Chemical Oxygen Demand (COD, 25.94 ± 11.37 mg/L), Arsenic (As, 0.26 ± 0.17 mg/L), and Lead (Pb, 0.23 ± 0.002 mg/L) exceeded acceptable thresholds. Spatial-temporal analysis revealed significant variations across sites, depths, and sampling dates. Major contaminant sources included discharges from the Tickfaw, Amite, and Blind rivers, as well as a vehicle accident on Pass Manchac. Seismic and drilling activities by Air Products and Chemicals had little to no observed impact. Four AI algorithms were also evaluated using different physical parameter inputs to predict December’s chemical pollutant levels, which were missing due to adverse weather. The LSTM model outperformed the others, achieving R2 values of 0.852 for COD, 0.869 for TN, 0.842 for As, and 0.921 for TP and Pb. Predictions indicated decreasing pollutant levels in December, which matched salinity and specific conductance measurements, and reverted to those observed in September and October. This pattern is attributed to the settling of contaminants from the Pass Manchac accident and ongoing pollutant sources from September and October.