Microplastics are ubiquitous and increasing in soil of a sprawling urban area, Phoenix (Arizona)
Microplastics are ubiquitous and increasing in soil of a sprawling urban area, Phoenix (Arizona)
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亚利桑那州凤凰城广阔城区的土壤中，微塑料无处不在，而且数量不断增加
DOI：
10.1016/j.scitotenv.2023.167617
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发表时间：
2023
影响因子：
9.8
通讯作者：
Herckes, Pierre
中科院分区：
文献类型：
--
作者：
Chandrakanthan, Kanchana;Fraser, Matthew P.;Herckes, Pierre
微塑料是在海洋和水生环境中被广泛研究的环境污染物;陆地生态系统是大多数微塑料的起源和积累的可能性，通常受到的关注较少。本研究的目的是调查在一个大的沙漠都市区，中央亚利桑那州-凤凰城长期生态研究（CAP-LTER）地区的微塑料的空间和时间的土壤浓度。亚利桑那州中部生态调查（ESCA）调查（2005年和2015年）的土壤样本被用来研究微塑料丰度的空间分布和时间变化。时间土壤微塑料数据由该地区（滕佩，亚利桑那州）中心位置的微塑料沉积通量补充，为期一年（2020年10月5日至2021年9月22日）。对样品进行处理，并在光学显微镜下对微塑料进行计数，以获得其在土壤中分布的定量信息。自2015年以来，凤凰城及索诺兰沙漠周边地区土壤样品中微塑料丰度的空间变化结果显示，微塑料在土壤中普遍存在且丰富（122至1299微塑料/kg），不同地点之间没有明显的趋势。微塑料沉积通量显示，局部地区有大量沉积（71至389微塑料/m2/天，平均沉积通量为178微塑料/m2/天），但沙尘暴对沉积的再悬浮和再分布作用可能导致空间趋势不明确。2005年和2015年调查的比较显示，微塑料丰度系统性增加，微塑料尺寸减少。显微拉曼光谱鉴定了各种塑料，包括PE、PS、PVC、PA、PES和PP。然而，大多数微塑料仍然是化学上无法识别的。聚乙烯存在于75%的采样点，是所有土壤样本中平均含量最高的聚合物。
Microplastics are environmental contaminants that have been extensively studied in marine and aquatic environments; terrestrial ecosystems, where most microplastics originate and have the potential to accumulate, typically receive less attention. This study aims to investigate the spatial and temporal soil concentrations of microplastics in a large desert metropolitan area, the Central Arizona–Phoenix Long-Term Ecological Research (CAP-LTER) area. Soil samples from the Ecological Survey of Central Arizona (ESCA) surveys (2005 and 2015) were leveraged to study spatial distributions and the temporal change of microplastic abundances. The temporal soil microplastics data were supplemented by microplastics deposition fluxes in a central location within the area (Tempe, AZ) for a period of one year (Oct 5th, 2020 to Sept 22nd, 2021). Samples were processed and microplastics were counted under an optical microscope to obtain quantitative information of their distribution in soil. Results for the spatial variation of the microplastic abundances in soil samples in Phoenix and the surrounding areas of the Sonoran Desert from 2015 depict microplastics as ubiquitous and abundant in soils (122 to 1299 microplastics/kg) with no clear trends between different locations. Microplastics deposition fluxes show substantial deposition in the local area (71 to 389 microplastics/m2/day with an average deposition flux of 178 microplastics/m2/day) but the role of resuspension and redistribution by dust storms to deposition may contribute to the unclear spatial trends. Comparison between the 2005 and 2015 surveys show a systematic increase in the abundance of microplastics and a decrease in microplastics size. Micro-Raman spectroscopy identified a variety of plastics including PE, PS, PVC, PA, PES and PP. However, a majority of microplastics remained chemically unidentifiable. Polyethylene was present in 75 % of the sampling sites and was the most abundant polymer on average in all soil samples.