Plastic particles less than 5 mm in size is referred as microplastics. These microplastics are causing environmental risks. The fundamental resources of the global food security system soil is also affected by it. But the distribution characteristics of MPs remain largely unknown.
Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences scientists have revealed the widespread presence of soil microplastics in tropical areas. This was spread in artificial ecosystems to natural ecosystems from top to deep soil layers.
The scientists have chosen two natural ecosystems and two artificial ecosystems in the Xishuangbanna tropical region. They have measured in the upper and lower layers of the soil, the abundance, size, type, shape, and colour of MPs.
They noticed that the dominant size of soil microplastics was less than 1 mm. They also found that the major shapes were fragments and fibres. Scientists also said that most microplastics were polyethylene, rayon, and polypropylene.
They have also said that the abundance of microplastics in the top soil layer was much higher than that in the deep soil layers. Scientists think that MP pollution is increasing seriously in the top soil in tropical areas.
The effect of land use on the occurrence and characteristics of microplastics was higher than soil depth. The presence of MPs in banana plantations was approximately 10 times than in rubber plantations. It was also 18 times of those in secondary forests and primary forests.
They have also said that the size of microplastics in the top soil layer in the secondary forest was bigger than that in the banana plantations and primary forests. But no size difference was found in the four land-use types in the deep soil layer.
The scientists said microplastics pollution has become an emerging problem across all major land uses in tropical areas.