Quantification and Analysis of Microplastics in Farmland Soils: Characterization, Sources, and Pathways

Patrick Chris Jomalema,Moslem Imani,Fezile Bethusile Mkhontfo,Angelbetter Marselian Massao,Bright Hubert Mbuya,Shang-Lien Lo,Nasra Shabani Jumanne,Nathan Thadeo Yoashi,Hoda Fakour,Nelson Naboth Lema,James Travor Mtweve

doi:10.3390/agriculture11040330

Patrick Chris Jomalema, Moslem Imani

Open Access

https://doi.org/10.3390/agriculture11040330

Copy DOI

Abstract

While microplastics (MPs) have been identified extensively in aquatic ecosystems, their presence remains largely unexplored in soil ecosystems. Considering the potential effect of MPs on soil biodiversity and function, the present study investigated and analyzed the abundance and characteristics of MPs in soil profile. Taking soil samples from Tainan city farms, as one of the hotspots of agricultural practices in Taiwan, concentrations, types, compositions, pathways, and sources of MPs in farmland soils were quantified. Results showed that MPs were found in all soil samples in different depths ranging from 12–117 items/m2 and MP abundance in farms adjacent to the suburban roads was about three times more than in enclosed farms separated from roads. Fragment and fibers were the main forms and low-density polyethylene was the dominant polymer of detected MPs. Historical land use, extensive application of plastic mulch, and utilization of fruit protection foams were identified as the main sources of MPs in farmlands. This study identifies the presence of MP emissions in farmland soils and investigates its features, which could serve as a framework for future studies into the ecological effects of MPs in the terrestrial environment.

Highlights

Plastic products are commonly used in daily life due to their low cost, malleability, and durability
Despite the fact that the rate of plastic recycling is increasing and most plastic products and their residues are still released into the environmen; in 2015, for example, an estimated 250 million tons of plastics were released into the ocean [2]
MPs were found in all soil samples in different depths ranging from 12–117 items/m2, with the mean concentration of 53.2 and 34.6 items/m2 in 5 and 20 cm depths, respectively (Table 3 and Figure 3)

Summary

Introduction

Plastic products are commonly used in daily life due to their low cost, malleability, and durability. Over the last 50 years, global plastic production has reached 9.1 billion tons, with an average annual growth rate of 8.7% [1]. Owing to massive processing and inefficient management, the plastic waste problem is unquestionably a major environmental concern. Despite the fact that the rate of plastic recycling is increasing and most plastic products and their residues are still released into the environmen; in 2015, for example, an estimated 250 million tons of plastics were released into the ocean [2]. Meso-, micro-, and nanoplastic particles are generally defined as

Objectives

Results

Conclusion