Effect of Cow Manure and Sawdust on Decreasing the Potential Risk of Lead due to Parsley Consumption

Vegetables are considered as an important part of the human food chain. Therefore, this study aimed to assess the potential risk of lead (Pb) due to parsley consumption cultured in the soil treated by sawdust and cow manure.

This factorial experiment was performed as a randomized complete block design. The treatments consisted of applying 0, 10, and 15 t/ha cow manure enriched with 0% and 5% (W/W) sawdust in the soil with pollution of 0, 400, 600, and 800 mg Pb/kg soil. The intended plant in this experiment was parsley. After 50 days, the Pb concentration in the soil and plant shoot was measured by atomic absorption spectrometry (AAS). Moreover, the relative risk coefficient for non-cancer diseases was estimated using the formula of the United States Environmental Protection Agency.

Our findings demonstrated that applying 10 and 15 t/ha of cow manure increased soil pH by 0.2 and 0.5 units, respectively. Furthermore, the addition of 10 t/ha of cow manure along with 5% (W/W) sawdust resulted in 1.6 units augmentation in the cation exchange capacity of the soil. In addition, the results indicated that using 15 t/ha of cow manure with 5% (W/W) sawdust could diminish the relative risk of Pb for non-cancerous diseases due to parsley consumption.

According to the results of the present study, parsley consumption in regions with Pb-polluted soil might have a high potential risk for non-cancerous diseases. It was indicated that the application of cow manure with sawdust had a significant effect on decreasing the potential risk of Pb. However, the role of soil pollution type and amount on reducing Pb potential risk should not be ignored.