Quantitative and Qualitative Assessment of Microplastics in Drinking Water, Raw Materials, and Animal Feed Additives

Background: Numerous studies have shown that exposing livestock to environmental and nutritional pollutants can endanger their health, leading to decreased production and product quality. Additionally, it can potentially transfer pollutants to higher levels of the food chain through contaminated products. Plastic materials have recently garnered significant attention as pollutants. Despite the crucial role of livestock and poultry products in human nutrition, providing a significant portion of the required protein, limited research has been conducted in this area. Objectives: This study was done to estimate the extent of microplastics in drinking water, complete diet, and certain feedstuffs in two dairy farms located in Tehran and Babol. Methods: Water and feed samples were collected in accordance with the standards of the National Organization of Iran. Microscopical examination of samples was done after digesting their organic matter contents with potassium hydroxide (KOH), and their size, color, and quantity were determined. The ingested number of microplastics by each cow was estimated based on the diet consumption. Results: The findings revealed the presence of a large number of microplastics in feedstuffs, varying in size and color. A significant difference in particle sizes of microplastic samples was observed between the two farms. It was estimated that each cow is ingesting over 5,000 microplastic particles daily through their feed. Conclusion: It can be concluded that dairy cows are exposed to microplastics through their diet, and corn grain was the most contaminated diet ingredient. Particle sizes range from 100 to 700 µm.