Pollution estimation and health risks assessment related to the agricultural application of mussel shell-derived...

In this study, estimation of pollution and assessment of health risks related to the agricultural application of mussel shell-derived chitosan as organic amendment were evaluated. Furthermore, considering WHO maximum permissible levels in soil, the application rates of chitosan to agricultural soils were calculated. Geo-accumulation index (I_geo), enrichment factor (EF), contamination factor (CF), pollution load index (PLI), and ecological risk index (ERI) were calculated. Mussel shell-derived chitosan generally did not contribute to soil metal loading when evaluated in terms of those indices. The highest hazard quotient for ingestion (HQ_ing) across male (ML), female (FML), and children (CL) followed the order Cr > Ni > Mn >Pb >Zn >Cu, while maximum HQ_ing among metals was observed in the order CL > FML > ML. For inhalation exposure, highest HQ_inh for all metals was also found in the order CL > FML > ML, with individual metal contributions following Mn > Ni > Cr >Zn >Pb >Cu. Maximum HQ_der exhibited the trend ML > FML > CL, and the metal-specific order for HQ_der was Cr > Pb > Ni >Zn >Mn >Cu. Hazard Index (HI) and Total HI for ingestion, inhalation and dermal exposure were all less than 1. Cancer risk was less than 1 × 10^-6. Consequently, there were no pollution and health risks associated with the use of musselshell‑derived chitosan in agriculture as organic amendment.