Exploring the Distribution of Microplastics and Heavy Metals in Agricultural Soils and the Evaluation of Risk Indices in Erbil City

Microplastics (MPs) and heavy metals (HMs) are emerging contaminants that pose potential risks to both environmental and human health. This investigation aims to evaluate the concentration, dispersion, and potential health hazards of microplastics and heavy metals in agricultural soils of Erbil City, Iraq. The quality of microplastics will be assessed by analysing soil samples collected from six agricultural sites using FT-IR spectroscopy. The study sites and plants contained various forms of microplastics, including PET, PA, PE, PS, and PP. Samples from S3–S5 may contain traces of aromatic structures, suggesting either PS contamination or degradation products of PET. The highest concentration of plastic particles per gram of soil was observed in S4 for PET, ranging from 0 to 2.88 ± 0.55. Heavy metals such as Ba, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were evaluated in soil samples and two plant species (Barbarea verna and Anethum graveolens) using ICP. The concentrations of chromium, manganese, nickel, iron, and zinc in the samples exceeded the FAO's permitted levels. Based on microplastic and heavy metal contamination, sites S2 and S6 were classified as medium risk, while site S4 demonstrated a high ecological risk. According to the data obtained from MPs and HMs, the strongest positive correlation was observed between aluminium and PET (Polyethylene Terephthalate) MPs (r = 0.82), while the correlation between Pb and PS was r = 0.78. Additionally, the study will assess whether MPs and HMs could enter the food chain, posing a risk to human health.