Heavy Metal Pollution

Heavy metals can be found in different products through natural and anthropogenic processes, and contamination can originate from various sources (Gall, Boyd, & Rajakuna, 2015). Contamination in agriculture could be from the soil, water and irrigation methods used. In hot dry season, the wastewater used to irrigate the crops in Zambian farms in East Africa were found to contain above acceptable levels of chromium and copper, and during the dry season, copper, chromium, nickel and cobalt in likewise considerably high amounts were identified. It was inferred that the large amounts of heavy metal in the soil were probably due to the seepage of water from the dams nearby the sample area and natural copper content of the soils because of the close

Leaf samples were collected from six plants such as the Azadirachta indica which is widely used in skin treatment because of its antibacterial and anti-virus characteristics, eucalyptus tree, and the Mangifera indica or mango tree. The heavy metal of the soil was also considered, as it may have been metal-polluted by the reports of greater burning and mining of coal activities in that area. It is the bioaccumulation factor, or leaf to soil pollution ratio, since the results could also be affected by aerial pollution. The largest amounts of metals (such as manganese, cadmium, and mercury) which accumulated were found in the Mangifera indica and eucalyptus tree leaves, among other samples. Although, the highest phytoextraction of the metals were observed in the Azadirachta indica leaves and was concluded to have been caused by the interaction of the alkaloids and the metals (Patel et al.,

(2014) have suggested that the source may vary according to air pollution and the provided feed. In a study about heavy metals in street-vended foods, results showed that lead is present among the top three most consumed street foods around University of Santo Tomas in Manila, Philippines which are deep-fried breaded quail eggs, grilled chicken intestines, and steamed dumplings. High levels of cadmium were detected in the chicken intestines, in contrast to the quail eggs and dumplings which only contained lead. The location of the stalls was also suggested to be one of the sources of the contamination (Abdulmajid et al.,