Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan.
Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan.
Chemosphere. 2021 Mar;267:129185. doi: 10.1016/j.chemosphere.2020.129185. Epub 2020 Dec 7.
Japanese agriculture uses large amounts of plastics. Fertilizer-containing plastic microcapsules with a diameter of 2-5 mm ("coated fertilizer") are not recovered after use, and after diffusion of the fertilizer components these microcapsules are found in large quantities, not only on agricultural land but also along the coast of Japan. Here, we investigated the accumulation of microcapsules derived from coated fertilizer in 19 paddy fields. Microcapsules were detected in all of the paddy fields surveyed, at concentrations in the range of 6-369 mg/kg (mean 144 mg/kg)-much higher than the concentrations of microplastics in farmlands in other countries. There was no difference in mean microcapsule concentration between sampling sites with continuous rice cultivation and those with crop rotation, but that of a paddy field that had never received coated fertilizer was significantly lower. Examination of the spatial distribution of microcapsules in one paddy field showed that there was a hot spot with a high concentration near the drainage outlet. This was likely due to the strong influence of irrigation water flowing from the water inlet to the drainage outlet. The amount of microcapsules accumulated in Japanese paddy fields, as estimated from our results, and the amount applied to the fields, as estimated from the statistics, were almost equivalent. Therefore, most of the microcapsules that have already been applied to paddy fields may continue to accumulate. The impact of these high concentrations of microcapsules on the soil environment needs to be assessed.
日本农业大量使用塑料。使用后直径 2-5 毫米的含肥料的塑料微胶囊（“包膜肥料”）无法回收，而在肥料成分扩散后，这些微胶囊大量存在，不仅在农田中，而且在日本沿海地区也大量存在。在这里，我们调查了 19 个稻田中包膜肥料衍生微胶囊的积累情况。在所调查的所有稻田中都检测到了微胶囊，浓度范围为 6-369 毫克/千克（平均值为 144 毫克/千克）-远高于其他国家农田中微塑料的浓度。连续种植水稻的采样点和轮作的采样点之间的平均微胶囊浓度没有差异，但从未使用过包膜肥料的稻田的微胶囊浓度明显较低。对一个稻田中微胶囊的空间分布进行检查表明，在排水口附近有一个浓度较高的热点。这可能是由于从进水口到排水口流动的灌溉水的强烈影响。根据我们的结果估计，日本稻田中积累的微胶囊数量与从统计数据估计的施用量几乎相当。因此，已经施用于稻田的微胶囊可能会继续积累。需要评估这些高浓度微胶囊对土壤环境的影响。
