Hiya
Thanks for that link.
However it says here:
The RP and TP were next leached in simulated rainwater in accordance with OECD
guidelines (OECD, 2004). The rain water was dripped onto columns containing the RP
or TP for 16 hours to mimic a significant rainfall event. The water was then collected
and tested for organic chemicals and metals. A preliminary test was conducted to
identify the pH at which the maximum amount of chemicals or metals would leach. Four
different acidity levels were tested and it was found that more metals leached when the
water was less acidic. Therefore, all further experiments were conducted using
simulated rainwater that was not acidic (pH 7.5). Unlike the harsh conditions created
with the organic solvent experiment, no organic chemicals were detected in the water
leachate, except formaldehyde. However, the formaldehyde was detected at levels that
were too low to be reliably quantified (i.e., <50 ppb). Barium, boron, magnesium,
manganese, potassium, silicon, and sodium leached from the RP but did not leach from
the TP in significant amounts, suggesting that most of these metals are from road dust
and not from the tires. Zinc was detected in the water from both the TP and RP
columns. The amount of zinc from the RP columns was about twice as much as was
found in the water from the TP columns.
So, there may be formaldehyde as well, although the levels are apparently too low. I'm quite cynical about this study since it's backed by multi national tire companies, unfortunately. I suppose, at the end of the day, it's a personal preference, whether or not to use tires to grow?
