ENVIRONMENTAL CHEMISTRY OF BENZOTHIAZOLES DERIVED FROM RUBBER

Benzothiazole (BT), 2-hydroxybenzothiazole (HOBT), and 2-(4-morpholino )benzothiazole (24MoBT) leach from crumb rubber material (CRM) and asp halt containing 1-3% CRM. To determine whether benzothiazoles would be an environmental problem if roads containing CRM-modified asphalt (CM A) were built in the state of Rhode Island, the source and fate of the se compounds were investigated. Benzothiazoles enter the environment f rom a number of sources such as the leaching of rubber products, fine particles of automobile tires, and antifreeze. Compared to the fluxes of benzothiazoles currently entering rivers from urban runoff, CMA roa ds may initially deliver substantially more benzothiazoles to the envi ronment; however, with time this source may diminish as the road ages. Because the benzothiazoles are water soluble, it is unlikely that the y will sorb to particles, settle to sediments, or be bioaccumulated. I n addition, BT can be volatilized, and BT and HOBT can be microbially degraded. Therefore, the environmental chemistry of these compounds su ggests that the inputs of benzothiazoles from CMA should not be harmfu l.