Water Pollution

Contamination from Transportation

Transportation activities exert significant influence on water conditions and quality. Emissions associated with marine transport represent the most direct source of water quality impact from the transportation sector. The main impact of marine transport operations on water quality derives from dredging, waste, ballast waters, and oil spills.

Dredging involves deepening harbor channels by removing sediment from the floor of the water bed. While the process is critical for creating and maintaining sufficient water depth for shipping operations and port accessibility, it also has a negative outcome for the marine environment. Specifically, dredging stirs up sediment that modifies the water's properties and biological diversity if not subject to decontamination techniques.

Waste generated by the operations of transport vessels at sea or ports can contain high levels of bacteria that could cause serious environmental and health problems when discharged directly into waters. Furthermore, waste that is not easily biodegradable can linger on the water's surface for long periods of time and impede maritime navigation, especially inland.

Ballast waters are required to control a ship's stability and to account for variances in weight distribution in cargo being transported. Ballast waters acquired in one region may contain non-native species or bacteria that become invasive and destructive when released into a new marine environment. Finally, oil spills from cargo vessel accidents represent one of the most serious problems of pollution from maritime transport activities.

In addition to direct water pollution from maritime transportation activities, there is a tremendous amount of fuel, chemicals, and other hazardous particulates discarded as by-products from airplanes, automobiles, railroads, and port operations every day around the globe. The pollution from sulferic and nitric acid deposits dispersed into the air, for example, is concentrated by atmospheric conditions and returns to Earth in the form of acid rain.

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