Laboratory for Coastal Ecology and Conservation, Faculty of Agriculture and Marine Science, Kochi University, 200 Monobe-Otsu, Nankoku, Kochi, 783-8502, Japan.
United Graduate School of Agriculture Sciences, Ehime University, Matsuyama, Japan.
Environ Monit Assess. 2023 Jun 7;195(7):808. doi: 10.1007/s10661-023-11410-7.
Measurements of microplastics in environmental and biological samples can be overestimated because of contaminants introduced during the analytical process. Knowledge of the potential sources and frequency of contamination during analysis is required to develop a protocol to prevent analytical errors. In this study, potential sources of contamination in the laboratory analysis of biological samples were evaluated, and reliable, inexpensive measures to prevent contamination were tested. Glass fibre filters, water samples, air samples, and chemicals [Fenton's reagent (HO and FeSO), and ZnCl] were tested for the presence of contaminants. Particulate contamination, including microplastics, was found in all samples when tested before application of any preventative measures. The following measures were evaluated for preventing contamination: (1) filtration of the water and chemical solutions using a glass fibre filter, (2) pre-combustion of the glass fibre filters, and (3) use of a clean booth for experimental work. The preventative measures reduced the levels of microplastics in all samples by 70-100%. The dominant polymers identified by Fourier transform infrared spectroscopy were polyethylene terephthalate, cellulose fibre (rayon), polystyrene, polyacrylonitrile, and polyethylene. With the preventative measures, the number of microplastics in the laboratory blanks was low enough to set the limit of detection to < 1. This limit of detection would be suitable for examination of microplastics contamination at the individual organism level, even at trace levels. Preventative countermeasures are essential to reduce overestimation of microplastics in biological samples and can be implemented at low cost.
在分析过程中引入的污染物会导致环境和生物样本中微塑料的测量值偏高。为了制定防止分析错误的方案，需要了解分析过程中潜在的污染源和污染频率。本研究评估了生物样本实验室分析中潜在的污染源，并测试了可靠且廉价的防止污染措施。对玻璃纤维滤器、水样、气样和化学物质[芬顿试剂（HO 和 FeSO）和 ZnCl]进行了污染物检测。在应用任何预防措施之前，所有测试样本中都发现了包括微塑料在内的颗粒状污染物。评估了以下几种防止污染的措施：（1）使用玻璃纤维滤器过滤水和化学溶液，（2）预先燃烧玻璃纤维滤器，（3）在清洁工作间进行实验。预防措施将所有样本中的微塑料水平降低了 70-100%。傅里叶变换红外光谱鉴定的主要聚合物为聚对苯二甲酸乙二醇酯、纤维素纤维（人造丝）、聚苯乙烯、聚丙烯腈和聚乙烯。通过采取预防措施，实验室空白样本中的微塑料数量低至检测限以下（<1）。该检测限适用于个体生物水平的微塑料污染检测，即使是痕量水平。预防对策对于减少生物样本中微塑料的高估至关重要，且可以低成本实施。
