This paper presents the results of a comprehensive characterization of chlorinated aromatic structures in high molecular weight organic material from bleached kraft mill effluents (BKME) and industrially unpolluted surface waters and groundwaters. After oxidative degradation (permanganate) of the organic materials and derivatization (diazomethane) of the degradation products obtained, the occurrence of chlorinated aromatic degradation products was investigated using gas chromatography/mass spectrometry. About twenty chlorinated methyl esters of aromatic carboxylic acids were identified in degraded samples of both industrial and natural origin. The identified compounds originated from chlorinated 4-hydroxyphenyl, 3,4-dihydroxyphenyl, guaiacyl, “condensed” guaiacyl, syringyl and veratryl units present as structural elements in the high molecular weight organic materials studied. Degradation products originating from mono- and dichlorinated 4-hydroxyphenyl units dominated in the degraded samples from unpolluted environments, whereas degradation products originating from chlorinated guaiacyl and syringyl units were most abundant in the degraded softwood and hardwood BKME samples. A special study of the monochlorinated isomers of 4-ethoxy-3-methoxybenzoic acid methyl ester showed that the 6-chloro isomer dominated in the degraded BKME samples whereas about equal amounts of the 5-chloro and 6-chloro isomers were found in degraded fulvic acids isolated from unpolluted waters.