ABSTRACT Microplastic pollution in aquatic systems has been reported globally at an alarming rate, with an increasing number of documented negative biological consequences. Research on microplastic pollution in freshwaters has barely begun in New Zealand, and few studies from smaller lotic systems such as streams exist globally. We investigated the extent of microplastic pollution within urban streams across New Zealand and determined if microplastic concentrations were related to human population density and urbanisation of streams. Fifty-two streams were surveyed across five urban agglomerations in January 2019. Microplastics were found in samples from all sites at densities ranging from <1 to 44 items/m3. This concentration range was comparable to global data but lower than reported in another recent New Zealand study, probably due to differences in sampling methodology. Microplastic pollution was similar across all urban centres, and neither length of urbanised catchment nor urban proportion of the stream were significant predictors of microplastic concentrations. These findings suggest microplastic pollution in New Zealand streams are comparable to larger aquatic systems globally, and that smaller urban streams are significant transport pathways for microplastics. We also recommend standardising microplastic sampling methods to a greater extent in the future, to improve comparability across studies.

中文翻译：

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新西兰城市河流中的微塑料污染：浓度、组成和影响

摘要 水生系统中的微塑料污染以惊人的速度在全球范围内被报道，越来越多的记录在案的负面生物后果。新西兰几乎没有开始对淡水中的微塑料污染进行研究，全球范围内很少有针对溪流等小型水流系统的研究。我们调查了新西兰城市河流中微塑料污染的程度，并确定了微塑料浓度是否与人口密度和河流城市化有关。2019 年 1 月，对五个城市群的 52 条河流进行了调查。在所有地点的样本中都发现了微塑料，密度范围从 <1 到 44 件/立方米。该浓度范围与全球数据相当，但低于新西兰最近的另一项研究报告的浓度范围，可能是由于抽样方法的不同。所有城市中心的微塑料污染都相似，城市化集水区的长度和河流的城市比例都不是微塑料浓度的重要预测因素。这些发现表明，新西兰溪流中的微塑料污染可与全球较大的水生系统相媲美，而较小的城市溪流是微塑料的重要运输途径。我们还建议在未来更大程度上标准化微塑料采样方法，以提高研究之间的可比性。这些发现表明，新西兰溪流中的微塑料污染可与全球较大的水生系统相媲美，而较小的城市溪流是微塑料的重要运输途径。我们还建议在未来更大程度上标准化微塑料采样方法，以提高研究之间的可比性。这些发现表明，新西兰溪流中的微塑料污染可与全球较大的水生系统相媲美，而较小的城市溪流是微塑料的重要运输途径。我们还建议在未来更大程度上标准化微塑料采样方法，以提高研究之间的可比性。