Pollutant Source Identification

Sudden mass mortality of aquatic organisms is occasionally observed in marine and coastal waters. One of the first questions that arises is whether the event was caused by natural environmental processes or by the introduction of pollutants into the aquatic environment. Initial investigations may confirm that contamination is the likely cause; however, identifying the original pollution source is often extremely challenging. In many cases, no discharge with characteristics matching the collected water or sediment samples can be found, and the exact timing of the pollutant release is unknown. This difficulty arises because pollutants undergo continuous physical transport, chemical transformation, and biological uptake after entering the aquatic environment. Over time, their original properties change through chemical reactions, while biological processes such as bioaccumulation, bioconcentration, and biomagnification further alter their distribution within the marine food web, making source identification increasingly complex.

Advanced numerical modeling provides an effective scientific approach for overcoming these challenges. By integrating physical, chemical, and biological processes, modeling technology can rapidly identify the most probable sources of contamination responsible for environmental degradation and mass mortality events. The modeling framework is developed through a systematic, step-by-step process. The first stage identifies all potential pollution sources by inventorying industrial, municipal, agricultural, and other human activities that may generate contaminant discharges. The second stage characterizes the types of waste materials and evaluates how they may transform into hazardous pollutants after entering the aquatic environment. The third stage simulates the physical transport, chemical transformation, and biological interactions of these pollutants to predict changes in their properties, spatial distribution, environmental persistence, and the time required for them to reach toxic concentrations. By interpreting these simulation results, the most probable source of pollution can be identified with a high level of scientific confidence.

Hydrodynamic Modeling and Advection–Dispersion Modeling are used to simulate water circulation, water level variations, pollutant transport, dispersion, and environmental fate. Suspended Sediment Transport Modeling evaluates the movement of contaminants associated with suspended sediments and their deposition patterns. Oil Spill Modeling is applied when the suspected contaminant consists of petroleum-derived compounds, particularly Polycyclic Aromatic Hydrocarbons (PAHs), to simulate their transport, weathering, and environmental behavior.

This integrated modeling framework enables decision-makers to identify pollution sources more accurately, reconstruct contamination events, assess environmental risks, support regulatory investigations, and develop effective mitigation and environmental protection strategies based on robust scientific evidence.