Biological safety assessment of functional activated carbons prepared from three agricultural wastes

This study prepared agricultural waste corn cob, bagasse pith and mushroom stalk activated carbons at different activation temperatures, and selected the activated carbon (AC) with better yield and iodine value for cytotoxicity and mutagenicity tests as well as biological safety assessment. The selected AC in regard to toxicity, the amount of residual bacteria was larger than that of the control group by more than 80%, meaning no cytotoxicity. The Salmonella typhimurium TA98 and TA100 of the AC did not exceed spontaneous revertants by more than two times, determining no mutagenicity. The feeding specimen for acute and subacute toxicity tests was 850"C corn cob AC. The observed weight, feed/water consumptions, feed conversion rate and urinalysis, organ weight, tissue slice as well as blood analysis in the results exhibited no significant difference to the Sprague-Dawley rat (SD rat) of the control group. The blood serum biochemical analysis result showed that the blood sugar of female rats of the control group and test group apparently decreased, but the blood urea nitrogen, aspartate aminotransferase and phosphorus of the test groups were higher than the normal range of SD rat of the National Laboratory Animal Center, and were not significantly different from the control group. According to the aforesaid results, the corn cob AC prepared at 850"C is in the test dose range of biological safety assessment, and is undoubtedly safe.