J. Great Lakes Res., 1980 Internat. Assoc. Great Lakes Res. 6( 4): 315-320 PETROLEUM HYDROCARBONS IN SEDIMENTS OF SAGINAW BAY, LAKE HURON Philip A. Meyers, Norishige Takeuchi' , and John A. Robbins 2 Oceanography Program Department of Atmospheric and Oceanic Science The University of Michigan Ann Arbor, Michigan 48109 ABSTRACT. The history of petroleum contamination of Saginaw Bay is given by a 60 cm core recording sediment accumulation over the last two centuries. Aliphatic hydrocarbon concentrations average 385 pgm/gm in modern sediments and progressively decrease from 10 cm to 40 cm in the core to average 30 pgm/gm in sediments deposited before 1876. An unresolved complex mixture of hydrocarbons diag- nostic of petroleum represents about 90 percent of the total concentration in all core sections deposited over the last 100 years. In older sediment, this decreases but still comprises 40 percent of the total at the bottom of the core. These patterns indicate a large input of nonbiogenic hydrocarbons which has accumu- lated in the sediments of Saginaw Bay. While a portion of these may originate from natural sources, such as forest fires and erosion of ancient sediments, we conservatively estimate that 2 to 4X 10 4 Tonne of petroleum hydrocarbons have been introduced to Saginaw Bay since the 1870s. INTRODUCTION Contribution of petroleum-derived hydrocarbons to the natural hydrocarbon contents of modern subaqueous sediments is widespread. Differences exist between petroleum hydrocarbons and the hydrocarbons of organisms which allow them to be distinguished from each other. Most notable is the high diversity of molecular structures in petroleum which include homologous series of straight-chain, branched, cyclic, and aromatic hydrocarbons (Farrington and Meyers 1975). In contrast, biological hydrocarbons are limited in their variety and, in particular, do not commonly contain cyclic structures (Douglas and Eglinton 1966). On the basis of these differences, the presence of hydrocarbons of a probable petroleum origin h'=lC' haa.n -=_ ...... ..... .... 1 ......... ...1: L_ £' _ appear to be related to the relative contribution of river-borne particles derived from various types of land runoff (Farrington and Quinn 1973a and 1973b, Gearing et al. 1976, Van Vleet and Quinn 1978, Hurtt and Quinn 1979). In addition, concen- trations decrease with depth in the sediments of Narragansett Bay, Rhode Island, and give a histori- cal record of the use of petroleum and its products in the surrounding urban and suburban regions (Van Vleet and Quinn 1977, Hurtt and Quinn 1979). Distributions of petroleum hydrocarbons similar to those described in marine areas have been found in freshwater sediments. In Lake Zug, Switzerland, the concentration and complexity of nearshore sediment hydrocarbons are highest close to cities and lowest near less populated shores (Giger pt nl 1074'1 Thp l'nnt ..'hllt'nn nf' ....