(full paper is archived in the Miller Library)
Title: Chromium concentrations in tunicates (Urochordata: ascidia) taken near Monterey, California; relation to local sewage outfalls
Student Author(s): Stibbs, Henry Howard
Faculty Advisor(s): Abbott, Donald
Location: Final Papers Biology 175H
Date: June 1970
Keywords: sewage pollution
Abstract: 1. Eighteen species of ascidians taken near Monterey, California, were analysed for chromim content using atomic absorption spectrophotometry. 2. The highest values (ppm dry weight) were found in the genera Eudistoma (E. psammion, 152.5; E. ritteri, 25.6; E. molle, 15.0) and Ritterella (R. pulchra, 69.6; R. rubra, 45.2). All are members of the Order Aplousobranchia. The lowest value was obtained in Stylea montereyensis (1.59 ppm dry weight). Seawater taken by the Hopkins Marine Station yielded a value of 0.095 ppm. 3. The chromium content o fascidians found near local domestic sewage outfalls was often lower than that of ascidians found in less polluted areas. The chromium concentration in three different samples of domestic sewage effluent (ranging from 0.000 to 0.008 ppm) was much lower than that in seawater from Monterey Bay (0.095 ppm).