Release of Nitrosamines and Nitrosamine Precursors from Scrap Tires

Abstract

Materials used during manufacturing of tires can be a source of nitrosamines and/or their precursors. Here, we examined the leaching of nitrosamines and nitrosamine precursors from scrap tires under different test conditions. Tire chips of different sizes and crumb rubber were exposed to leaching solutions with pH values ranging from 4.0 to 10.0. Leachates collected from tires were analyzed for nitrosamines. Leachates were oxidized with chloramine, ozone, or ozone followed by chloramine to quantify the amount of nitrosamine precursors. While N-nitrosodimethylamine (NDMA) and N-nitrosomorpholine (NMOR) constituted more than 90% of nitrosamines, Nnitrosodibutylamine and N-nitrosopyrrolidine were also detected in the leachates. Chloramination of the leachate was found to form additional NDMA, NMOR, and other nitrosamines. While ozonation alone did not lead to formation of NDMA or NMOR, lower levels of formation of NDMA and NMOR were observed when ozonation was followed by chloramination as compared to those for only chloramination. This suggests that ozonation reduced the reactivity of nitrosamine precursors leaching from scrap tires. Furthermore, the levels of leaching of NDMA and NMOR precursors were higher under lower-pH conditions, which can be attributed to the higher solubility of protonated amines. From an environmental standpoint, these results suggest that water in contact with tire scraps (such as in urban runoff, bed media for ballast water and wastewater treatment, and ground cover for playgrounds) may potentially contain nitrosamines and nitrosamine precursors, and the amount of precursor leaching may change with the size of the tire scraps.

Design of a Zn Single-Site Curing Activator for a More Sustainable Sulfur Cross-Link Formation in Rubber

“…Despite the technological level of rubber materials and in particular of tires, which represent worldwide their major application, in the last decades, the sustainability of their production, use, and disposal has become a main issue. , Nowadays, in the frame of a gradual but still far transformation of the rubber materials’ life cycle into a circular economy model, several efforts are required to promote a more sustainable use/reuse of the raw materials in rubber products, lowering the use of toxic and potentially harmful materials, at the same time keeping highly functional and structural properties suitable for the final material applications. − …”

Animal Feedlots and Domestic Wastewater Discharges are Likely Sources of N-Nitrosodimethylamine (NDMA) Precursors in Midwestern Watersheds

“…Previous studies reported that nitrosamines and their precursors were negligible in pristine headwaters and that municipal wastewater effluents were the dominant source of nitrosamines in surface water. , Agricultural sources of NDMA precursors include cropland runoff and wastewater from animal husbandry operations that could release herbicides (i.e., diuron and isoproturon) and veterinary antibiotics (i.e., tetracyclines and macrolides), respectively. ,, Urban runoff also releases NDMA precursors into surface waters, especially during rainfall events . Nitrosamines and their precursors may also be released from scrap tires, which likely contribute to the NDMA precursor pool in urban runoff . Many prior investigations involved sampling directly from point sources, such as WWTP effluents, hospital wastewater, laundry water, agricultural runoff channels, stormwater drains, and manure or waste lagoons at animal operation facilities. ,− The receiving waters, which serve as the source water for drinking water treatment plants, have received considerably less attention.…”

“…12 Nitrosamines and their precursors may also be released from scrap tires, which likely contribute to the NDMA precursor pool in urban runoff. 13 Many prior investigations involved sampling directly from point sources, such as WWTP effluents, hospital wastewater, laundry water, agricultural runoff channels, stormwater drains, and manure or waste lagoons at animal operation facilities. 8,14−17 The receiving waters, which serve as the source water for drinking water treatment plants, have received considerably less attention.…”

Microbial community shifts induced by plastic and zinc as substitutes of tire abrasion

“…One important pollution source is tire abrasion 7 , 8 . Tires contain numerous substances like carbon black, additives, fabric, curing agents, sulfur, metals, but also styrene and butadiene, which are precursors of polystyrene 9 – 12 . Wearing off the tire leaves particles on the surface, which, due to abrasion and UV radiation, degrade to micro- and nanoplastic 4 , 13 – 16 .…”