Micro- and nano-plastics in edible fruit and vegetables. The first diet risks assessment for the general population

Abstract

Microplastics (MPs) represent a current public health concern since toxicity has not yet fully investigated. They were found in several foods, but to the best of our knowledge, at this time no data was reported for the edible vegetables and fruits. We focused on diet exposure aiming to evaluate the number and the size (<10 μm) of MPs in the most commonly consumed vegetables and fruits, in relation to their recommended daily intake too. MPs extraction and analysis were carried out using an innovative Italian methodology and SEM-EDX, respectively. Finally, we calculated the Estimated Daily Intakes (EDIs) for adults and children for each type of vegetal and fruit. The higher median (IQR) level of MPs in fruit and vegetable samples was 223,000 (52,600-307,750) and 97,800 (72,175-130,500), respectively. In particular, apples were the most contaminated fruit samples, while carrot was the most contaminated vegetable. Conversely, the lower median (IQR) level was observed in lettuce samples 52,050 (26,375-75,425). Both vegetable and fruit samples MPs levels were characterized by wide variability. The smallest size of MPs was found in the carrot samples (1.51 μm), while the biggest ones were found in the lettuce (2.52 μm). Both vegetable and fruit samples had size of the MPs characterized by low variability. We found the highest median level of MPs in samples purchased from the "fruiter 3" (124,900 p/g) and the lowest in those purchased in "supermarket" (87,600 p/g). The median size of the MPs had overlapping dimensions in all the purchase sites, with the exception of the samples purchased at the "shop at km zero 2″ which had slightly smaller size (1.81 μm). The highest adults' (4.62 E+05) and children's (1.41 E+06) EDIs are due the ingestion of apples, instead the lowest are due to the ingestion of carrots (adults: 2.96 E+04; children: 1.15 E+05). We hypothesized that the mechanism of uptake and translocation of MPs can be the same described and reported for carbon-nanomaterials. This may be a possible translocation route of MPs by environment to vegetables permitting, so, the translocation or uptake inside of their biological systems. Based on the results obtained it is urgent important to perform toxicological and epidemiological studies to investigate for the possible effects of MPs on human health.