Assessment of potential health hazards associated with arsenic concentration from volcanic hosted hydrothermal systems in Rungwe, southern Tanzania

This study reports on an assessment of health hazards associated with As concentration from volcanic hosted hydrothermal systems in the Rungwe area, Tanzania. A total of 48 water samples from rivers, cold and hot springs in the study area were collected and analyzed both “in situ” and in the laboratory by ICP-MS, potentiometric, calorimetric, titrimetric and HACH physical water properties methods. In water, the trace elements As, Ce, Cu, La, Li, Mo, Pb and Rb were analyzed as well as major elements Ca, Na, K, Mg, Si, SO4, HCO3 and Cl. In soil only As was analyzed. The results revealed relatively large chemical and physical differences between groundwater and surface water. With the exception of Cu, the heavy elements and F increases in the order river water < cold spring water< hot spring water. As values in hot springs are 5-times higher than the values in rivers and cold springs. Similarly, Fe, Pb, Zn and F values in hot springs are respectively 2-fold, 5-fold, 2-fold and 2- fold higher than in cold springs. The highest As concentration in hot spring was 13 times the World Health Organization (WHO) recommended value and twice as much as the Tanzania Bureau of Standard (TBS) value. In this case there is a need for concern over the intake level of As through drinking water in Kilambo villages near hot springs at the current time, in spite of the uncertainties in the values reported here. In case of surface water, there is no necessity for any restriction on its use for domestic purpose. In view of the fact that As tend to accumulate in the food web with the potential to cause health effects, further investigations on the accumulation of As in residents of communities residing at Kilambo villages is recommended.