Metal and metalloid contamination in roadside soil and wild rats around a Pb-Zn mine in Kabwe, Zambia

Metal (Cr, Co, Cu, Zn, Cd, Pb, Ni) and metalloid (As) accumulation was studied in roadside soil and wild rat (Rattus sp.) samples from near a Pb-Zn mine (Kabwe, Zambia) and the capital city of Zambia (Lusaka). The concentrations of the seven metals and As in the soil samples and Pb in the rat tissue samples were quantified using atomic absorption spectroscopy. The concentrations of Pb, Zn, Cu, Cd, and As in Kabwe soil were much higher than benchmark values. Geographic Information System analysis indicated the source of metal pollution was mining and smelting activity. Interestingly, the area south of the mine was more highly contaminated even though the prevailing wind flow was westward. Wild rats from Kabwe had much higher tissue concentrations of Pb than those from Lusaka. Their body weight and renal Pb levels were negatively correlated, which suggests that mining activity might affect terrestrial animals in Kabwe.     

Causes of accidents by soy sauce squeezing residue and fish meal

Recently, a demand for the reuse, recycling and reduction of waste has arisen. In the food industry, efforts are being made to recycle the waste produced and use resources more efficiently. However, some industrial food waste or recycled waste materials generate heat as a result of fermentation and oxidation, which leads to an increase in temperature during storage and transport, ultimately resulting in spontaneous ignition. In this study, we examined the fermentation and heat generation by soy sauce squeezing residue (SSSR) produced during the brewing of soy sauce and by the fish meal produced during the processing of fish residue. The objective of this study was to investigate the causes of fires using various heat analysis methods and to understand the processes of fermentation and oxidation of food industry waste that lead to spontaneous ignition.