Spatial and temporal variations of microplastic concentrations in Portland's freshwater ecosystems
Spatial and temporal variations of microplastic concentrations in Portland's freshwater ecosystems
复制标题
波特兰淡水生态系统中微塑料浓度的时空变化
DOI：
10.1016/j.scitotenv.2022.155143
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发表时间：
2022
影响因子：
9.8
通讯作者：
Brander, Susanne
中科院分区：
文献类型：
--
作者：
Talbot, Rebecca;Granek, Elise;Chang, Heejun;Wood, Rosemary;Brander, Susanne
虽然微塑料是各种环境分区中日益受到关注的污染物，但对城市河流中微塑料的来源和输送途径知之甚少。我们研究了微塑料浓度与各种时空因素之间的关系（例如，土地利用，主干道长度，水流速度，降水量）在两个流域沿着在波特兰大都市区的城乡梯度。在8月，9月和2月收集样品，并分析总微塑料计数和类型。非参数统计被用来评估潜在的关系与解释变量，在子流域和近流尺度。8月份，微塑料浓度明显高于2月份。8月份的浓度也与流速呈负相关，这表明较低的流速可能促进了微塑料的积累。8月份的小颗粒塑料颗粒（< 100 μm）多于9月份和2月份，而2月份的大颗粒塑料颗粒多于其他月份。微塑料浓度呈正相关的24小时前期降水在2月。在近河流水位处，雨季微塑料浓度与农田之间存在负相关关系。结果表明，近流变量可能会更强烈地影响微塑料的存在和丰富的波特兰的水道比子流域尺度变量。碎片是最常见的微塑性形态，以灰色颗粒和聚合物聚乙烯为主。这项研究的结果可以为有关微塑料废物的管理决策提供信息，并确定可能受益于补救措施的微塑料污染热点。
While microplastics are a pollutant of growing concern in various environmental compartments, less is known regarding the sources and delivery pathways of microplastics in urban rivers. We investigated the relationship between microplastic concentrations and various spatiotemporal factors (e.g., land use, arterial road length, water velocity, precipitation) in two watersheds along an urban-rural gradient in the Portland metropolitan area. Samples were collected in August, September, and February and were analyzed for total microplastic count and type. Nonparametric statistics were used to evaluate potential relationships with the explanatory variables, derived at both the subwatershed and near stream scales. In August, microplastic concentrations were significantly higher than in February. August concentrations also negatively correlated with flow rate, suggesting that lower flow rates may have facilitated the accumulation of microplastics. Smaller size microplastic particles (< 100 μm) were found more in August than September and February, while larger size particles were more dominant in February than the other months. Microplastic concentrations were positively related to 24-h antecedent precipitation in February. Negative correlations existed between wet season microplastic concentrations and agricultural lands at the near stream level. The results indicate that near stream variables may more strongly influence the presence and abundance of microplastics in Portland's waterways than subwatershed-scale variables. Fragments were the most commonly observed microplastic morphology, with a dominance of gray particles and the polymer polyethylene. The findings of this study can inform management decisions regarding microplastic waste and identify hotspots of microplastic pollution that may benefit from remediation.