Detection of plastics particles in equine blood by Scanning Electron Microscopy

The study was conducted in the province of Guayas, located in the coastal region of Ecuador. The researchers analysed blood samples from 30 horses of different breeds (purebred, pony and mixed breeds) to detect the presence of micro- and nanoplastics (MPs and NPs). Blood smear and scanning electron microscopy (SEM) techniques were used to identify and quantify plastic particles in randomly selected animals aged between 2 and 12 years, with a body weight (BW) between 100 and 380 kg and a body condition score (BCS) between 5 and 6 (on a scale of 1 to 9), fed on natural grass and balanced supplements. The results did not show the presence of MPs, but NPs were identified in the blood smear of all animals, with an average of 51 particles per field of 1700 square microns (µm²) at a depth of 5 micrometres (µm) and an average size of 426.33 nanometres (nm). No significant difference was found in the number or size of NP particles between the sexes (females and males) (P=0.288); a greater presence of NPs was observed in younger horses (P<0.040). The pure-blood breed had a larger size of plastic particles (P < 0.020) and the crossbreeds had a greater amount of NP particles (P < 0.010) compared to other breeds. The research concludes that NPs are present in equine blood, highlighting the ability of these contaminants to enter the body and potentially cause adverse health effects. In particular, younger animals showed a higher presence of NPs in blood, suggesting that the effects of exposure may be more severe in the early stages of life.