FEASIBILITY OF PHYTOREMEDIATION AT THE OLD KABWE MINE SITE: IMPLICATIONS FOR FATE AND TRANSPORT OF HEAVY METALS NEAR ABANDONED MINE SITES

Mining activities have globally altered the natural landscape and discharged large amounts of waste covering extensive areas, where they have posed serious pollution hazards to the environment and public health. In addition to altering the natural landscape, metalliferous mine tailings and stockpiled overburden pose grave pollution hazards to the environment, to human health and to livelihood resources, such as agriculture. Metalliferous mine environments are usually polluted with heavy metals which can be toxic, such as lead, arsenic, cadmium and mercury. These are ingested through a variety of channels including soil, water and food, leading to cumulative and serious health hazards in human beings, plants and animals. As the metals are non-biodegradable, the impact can be long lasting and hazardous to public health as well as wildlife. Arsenic is a known carcinogen and can cause cancer of the skin, lungs, liver and bladder. Cadmium chronic exposure to lower levels of human body leads to a buildup in the kidneys and possible kidney disease, lung damage, and fragile bones. Exposure to high lead levels can severely damage the brain and kidneys and ultimately cause death. The nervous system is very sensitive to all forms of mercury. Mine waste dumps are unfortunately often built near human settlements where the contaminated groundwater pose a threat to farming communities in many developing countries. Due to high levels of poverty, these dumps are sometimes scavenged by local communities including young children for various needs. Children also patronize abandoned dumps for recreation. This ongoing study investigates the feasibility of phytoremediation at the old Kabwe mine site in the African country of Zambia. Preliminary assessment indicates that, taken in the context of efficiency as well as remediation costs and sustainability, site specific agro/phyto-mining measures appear promising but need to be integrated with bioenergy production and/or other appropriate value-additions to the plants in order for the phytoremediation to succeed. The study further discusses lessons and implications for similar contaminated abandoned mine sites elsewhere, such as in Colorado, where the number of abandoned mine sites is estimated to exceed 1000.