All terms used in this article shall have the meanings given to them in § 270-4 of this chapter, except that when used in this article, the term "pollutant" shall have the following meaning:
Dredged spoil, filter backwash, solid waste, incinerator residue, treated or untreated sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand and industrial, municipal, and agricultural waste and ballast discharged into water, any of which may cause or might reasonably be expected to cause pollution of the waters of the state in contravention of water quality standards.