Dm. Demarini et al., MUTAGENICITY AND CHEMICAL-ANALYSIS OF EMISSIONS FROM THE OPEN BURNINGOF SCRAP RUBBER TIRES, Environmental science & technology, 28(1), 1994, pp. 136-141
The Salmonella mutagenicity assay and chemical analyses were used to e
valuate the emissions from the open burning of scrap rubber tires that
had been cut into either of two sizes, CHUNK or SHRED. The mutagenic
potencies in strain TA98 of the dichloromethane-extractable particulat
e organics (2-12 revertants/mug) were generally greater than that of t
he semivolatiles (approximately 1-9 revertants/mug). In addition, the
open burning of CHUNK tires produced a higher burn rate (approximately
4-9 vs approximately 1 kg/h) and more potent organics in the presence
of S9 than did SHRED tires. This may have reflected the greater produ
ction of S9-dependent mutagens, such as polycyclic aromatic hydrocarbo
ns (PAHs), under the combustion conditions generated by the CHUNK tire
s. Bioassays using selected strains of Salmonella indicated that dinit
roarenes or aromatic amines (but not mononitroaromatics) accounted for
much of the mutagenic activity measured in the absence of S9. A wide
variety of PAHs was detected in the particulate organics. The mutageni
c emission factor for the open burning of scrap rubber tires (approxim
ately 8 X 10(7) revertants/kg of tire burned) was 3-4 orders of magnit
ude greater than the values for the combustion of oil, coal, or wood i
n utility boilers; it was most similar to values for the open burning
of wood or plastic. These results demonstrate for the first time that
the open burning of scrap rubber tires produces a high mutagenic emiss
ion factor, posing potential environmental and health effects.