Objective To verify microplastic pollution of a sludge stacking site to surrounding soil, and to explore the microplastics pollution in the feces and large intestine tissues of pigs raised near the sludge stacking site.
Methods Samples of surface soil around a sludge dump were collected; feces samples and tissue specimens of large intestine of a black pig raised by a farmer at the place close to the sludge dump site were collected simultaneously. The samples and specimens were observed with stereomicroscope and polarized light microscope for preliminary identification of microplastics. Qualitative and quantitative scanning analysis on the microplastics in the samples and specimens were carried out using laser infrared imaging system (Agilent 8700 LDIR).
Results The abundance of microplastics in the surface soil samples, feces samples and large intestine specimens were 354 – 524/10 g, 1 120/10 g and 96/10 g. The main microplastics in the large intestine specimens were polypropylene (PP), polystyrene (PS), polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET), with the abundances wereof 40/10g, 17/10 g, 13/10 g and 7/10 g, respectively. The majority (72.4%) of the detected microplastics are of the particle size less than 200 μm and the characteristics of microplastics in the large intestine specimens is different from that of the soil sapmples.
Conclusion Microplastics were detected in large intestine tissues of a pig raised near a sludge dump site and the microplastics may be related to the microplastic soil pollution attributed to the sludge dump site.
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