STUDY THE HEAVY METAL IN THE BAKERY PRODUCTS OF KHULNA CITY, BANGLADESH AND POSSIBLE HEALTH RISK (MS Thesis)- Degree Awarded

Abstract:

This study was conducted to determine the levels of six heavy metals ( Cr, Mn, Cu, Ni, Cd, and Pb) in some bakery products (bread, biscuits, and cake) of Khulna city and to assess their associated carcinogenic and non-carcinogenic risk on human health. A total of 36 samples were collected from 12 bakery shops that are commercially accessible within Khulna City Corporation (KCC). The samples were analyzed by using atomic absorption spectrophotometry (AAS). In bread the concentration of heavy metals showed in the following range (0.432 to 1.79) mg/kg for Cr, (0.32 to 1.81) mg/kg for Mn, (0.312 to 1.91) mg/kg for Cu, (0.109 to 3.19) mg/kg for Ni, (0.03 to 1.906) mg/kg for Cd and (0.04 to 0.1) mg/kg for Pb. In biscuit the concentration ranged from (0.311 to 1.63) mg/kg for Cr, (0.32 to 1.69) mg/kg for Mn, (0.32 to 1.79) mg/kg for Cu, (0.03 to 3.07) mg/kg for Ni, (0.03 to 1.06) mg/kg for Cd and (0.02 to 0.11) mg/kg for Pb. Similar trends were found for cake and the values were (0.39 to 1.7) mg/kg for Cr, (0.39 to 1.74) mg/kg for Mn, (0.37 to 1.87) mg/kg for Cu, (0.1 to 3.21) mg/kg for Ni, (0.07 to 1.81) mg/kg for Cd and (0.03 to 0.06) mg/kg for Pb. The results showed that Cr, Mn, Cu and Pb across all three types of bakery products were within the FAO/WHO maximum permissible limit. But elevated level of Ni and Cd was found in some bakeries such as B-2, B-4 and B-8. Non-carcinogenic risk indicators such as EDI, THQ, TTHQ, DIM and HRI were well below the threshold limit 1, suggesting minimal non carcinogenic risk. On the other hand,  carcinogenic risk indicators ILCR and ΣILCR values for cake were well below the threshold limit 1×10⁻⁴. However, in bread and biscuit ILCR and ΣILCR values for Cr slightly exceeded the permissible limit but the value is not alarmingly high, suggesting a low but present cancer risk with long-term intake. Metal concentration in common raw materials (flour, water, baking soda, sugar and salt) across all the products were very minimal, indicating that contamination likely due to processing techniques, packaging, transportation, storage rather than raw materials. Regular monitoring, good hygiene practice and processing standard are recommended to reduce heavy metal concentration in bakery products.

• Supervision