San Diego State University Research Foundation, San Diego, CA, 92182, USA.
Department of Civil, Construction, and Environmental Engineering, San Diego State University, San Diego, CA, 92182, USA.
Environ Pollut. 2023 Oct 1;334:122116. doi: 10.1016/j.envpol.2023.122116. Epub 2023 Jun 30.
Tire tread particles (TTP) are environmentally prevalent microplastics and generate toxic aqueous leachate. We determined the total carbon and nitrogen leachate concentrations and chemical profiles from micron (∼32 μm) and centimeter (∼1 cm) TTP leachate over 12 days. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were used to measure the concentration of leached compounds. Nontargeted chemical analysis by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS) was used to compare the chemical profiles of leachates. After leaching for 12 days, DOC was 4.0 times higher in the micron TTP leachate than in the centimeter TTP leachate, and TDN was 2.6 times higher. The total GC×GC/TOF-MS chromatographic feature peak area was 2.9 times greater in the micron TTP leachate than the centimeter TTP leachate, and similarly, the total relative abundance of 54 tentatively identified compounds was 3.3 times greater. We identified frequently measured tire-related chemicals, such as 6PPD, N-cyclohexyl-N'-phenylurea (CPU), and hexa(methoxymethyl)melamine (HMMM), but nearly 50% of detected chemicals were not previously reported in tire literature or lacked toxicity information. Overall, the results demonstrate that smaller TTP have a greater potential to leach chemicals into aquatic systems, but a significant portion of these chemicals are not well-studied and require further risk assessment.
轮胎胎面颗粒（TTP）是环境中普遍存在的微塑料，并会产生有毒的水溶浸出物。我们测定了微（∼32μm）和厘米（∼1cm）TTP 浸出物在 12 天内的总碳和总氮浸出液浓度和化学特征。溶解有机碳（DOC）和总溶解氮（TDN）用于测量浸出化合物的浓度。采用全面二维气相色谱-飞行时间质谱联用（GC×GC/TOF-MS）的非靶向化学分析比较了浸出液的化学特征。在 12 天的浸出后，微 TTP 浸出液中的 DOC 是厘米 TTP 浸出液的 4.0 倍，TDN 是其 2.6 倍。微 TTP 浸出液的总 GC×GC/TOF-MS 色谱特征峰面积比厘米 TTP 浸出液高 2.9 倍，54 种暂定鉴定化合物的总相对丰度高 3.3 倍。我们鉴定了经常测量的轮胎相关化学物质，如 6PPD、N-环己基-N'-苯基脲（CPU）和六亚甲基双（甲氧基甲基）三聚氰胺（HMMM），但近 50%的检测化学物质以前在轮胎文献中未被报道或缺乏毒性信息。总体而言，结果表明，较小的 TTP 更有可能将化学物质浸出到水生系统中，但这些化学物质中有相当大的一部分尚未得到充分研究，需要进一步进行风险评估。
