The impact of mine tailings on snouted harvester termites, Trinervitermes trinervoides (Sjostedt) (Isoptera: Termitidae), in the Vaal river region

摘要

Mining activities are well known for their negative effects on the environment andudanimals, due to the deposition of large volume of wastes in the form of tailings onudthe soil. These wastes or tailings contain high levels of heavy metals, sulphidesudand cyanide. Heavy metals are one of the most persistent pollutants in theudenvironment and have been shown to bioaccumulate in animals. The purpose ofudthis investigation was to evaluate the impact of mine tailings on the snoutedudharvester termite, Trinervitermes trinervoides, inhabiting the Vaal River region.udThese termites play a significant role in the food chain as they provide a proteinandudenergy-rich food source to numerous predators therefore any bioaccumulationudof heavy metals may adversely impact the food chain. Three aspects of the termiteudbiology was studied, namely, the density and distribution of the termite mounds,udthe temperature profile of the mounds and the heavy metal content of the termites,udmounds and surrounding soil. Three sites were chosen in accordance to theirudposition relative to a tailings dam with the furthest site being the Control site. Theudmost contaminated site and site closest to the tailings dam (AEL site) had theudhighest termite mound density, followed by the least contaminated site (Controludsite) and then the intermediately contaminated site (West Complex). The AEL siteudhad many incipient mounds but few large mounds indicating that although thereudwas a high turnover of new mounds, the longevity of these mounds was low.udHigher densities at the AEL site may be explained by the water table being closerudto the surface as a result of the tailings dam, allowing the termites easier access toudwater and hence a more favourable environment within the mound. The centreudtemperatures of the mounds at all three sites were kept constant on a monthlyudbasis but fluctuated on a seasonal basis. The West Complex site had the highestudand most variable centre mound temperatures. The average heavy metal content ofudthe surface layer did not differ significantly from the average heavy metal contentudof the mounds at the AEL and West Complex site, indicating that the termites areudnot making heavy metals more bioavailable to the environment. The termites atudthe AEL site had the highest levels of Cu and Zn out of all the sites andudaccumulated these metals to levels toxic to mammals. Alates (a major food sourceudfor many animals) however, did not accumulate any heavy metals therefore it isudunlikely the food chain is being negatively impacted by the termites. From thisudstudy there is no indication that the snouted harvester termite density or behaviourudare being impacted by the tailings dams