A thoroughly documented discussion of methods for sampling and identifying pollutant oils in industrial watercourses is presented. Simple, yet quantitative, methods for retrieval of oil slick specimens are described which are usable on all types of pollutant layers, ranging from near-zero thickness to inches in thickness, irrespective of their degree of weathering, emulsification, or admixture with debris. Techniques which fail in such situations are also described. An analytical scheme for the determination of organic pollutants in industrial waters by chloroform extraction (below pH 8) and carbon tetrachloride extraction (above pH 8) is demonstrated to be superior to more generally used hexane extraction techniques. Numerous examples illustrating the use of gas chromatography and infrared spectroscopy for pollution analysis are presented. Applications of the various analytical methods considered are discussed with specific reference to the correlation of oil slick components with pollutants in industrial outfalls; the evaluation of an inverted siphon sewer as an oil trap; the evaluation of an air barrier as a slick container; the evaluation of surface oil skimmers; and the identification of spilled oils for enforcement actions. The burden of oily pollutants entering and exiting the Buffalo River, and deposited along its shoreline and in its sediments, is estimated for the 1968-1970 period and compared with available data on the river water quality as early as 1964.