Studies on the fates of organic contaminants in aquatic environments

Christopher Michael Reddy, University of Rhode Island


In the first study, the environmental chemistry of benzothiazoles was evaluated. Benzothiazole (BT), 2-hydroxybenzothiazole (HOBT), and 2-(4-morpholino)-benzothiazole (24MoBT) leach from crumb rubber material (CRM) and asphalt containing 1% to 3% CRM. To determine whether benzothiazoles would be an environmental problem if roads containing CRM-modified asphalt (CMA) were built, the source and fate of these compounds were investigated. Because the benzothiazoles are water soluble, it is unlikely that they will sorb to particles, settle to sediments, or be bioaccumulated. In addition, BT can be volatilized, and BT and HOBT can be microbially degraded. The environmental chemistry of spilled No.2 fuel oil in the coastal waters of Rhode Island and Point Judith Pond (PJP) was investigated in the second study. On January 1996, the North Cape oil barge ran aground near Moonstone Beach, RI and spilled over 2,700 metric tons of No. 2 fuel oils. After the spill, PAHs were removed from the water column in PJP according to first-order kinetics, with removal rates of 10 to 30% day$\sp{-1}.$ Based on simple calculations, flushing and evaporation were the most important processes removing the PAHs from PJP. In the final study, free and bound fractions of six different benzotriazoles (BZTs) in marine and freshwater sediment cores were examined to investigate how anthropogenic compounds interact with organic matter. The free fraction was operationally defined as the fraction of BZTs that was removed with several acetonitrile/hexane extractions, and the bound fraction was that portion of BZTs removed by hexane extraction after saponifying the residue remaining from the initial solvent extraction. The % bound of the BZTs ranged from 0 to 9% of the total and varied with each compound, sediment depth, and type of organic matter. BZTs that did not have alkyl substitution adjacent to the 2$\sp\prime$-hydroxy group were more likely to be bound than compounds that had alkyl substituents adjacent to this group. It appears that these compounds may be chemically associated to the sedimentary organic matter through the hydroxy group, and the binding reaction is reduced by steric hindrance.

Subject Area

Environmental science|Analytical chemistry|Organic chemistry

Recommended Citation

Christopher Michael Reddy, "Studies on the fates of organic contaminants in aquatic environments" (1997). Dissertations and Master's Theses (Campus Access). Paper AAI9831117.