Assessment of levels and distribution of progesterone in receiving waters and wastewaters in the vicinity of Arusha city,Tanzania

Abstract

This study aimed at investigating the levels and distribution of progesterone in receiving waters and wastewaters in Arusha, a fast-growing urban area and third largest city in Tanzania. Also, intend to assess the efficiency of waste stabilisation ponds (WSP) and constructed wetland (CW) in removing progesterone. The study was conducted along the Themi River, (WSPs) and CW. Progesterone was detected and quantified by using an Enzyme-Linked Immunosorbent Assay (ELISA) kit. For Themi River samples, the level of progesterone obtained ranged from ‘no detection’ to 439.00 ng/L with a mean value of 120.30 ng/L. The levels detected were significantly higher in the midstream three times and seven times than upstream and downstream, respectively (P ˂ 0.05). Progesterone was spatially distributed much at midstream than upstream and downstream. The elevated values at midstream were attributable to livestock, WSPs and household effluents; agricultural activities; and sewage infiltration. WSPs were observed to release 215 ng/L of progesterone at effluent with zero progesterone detected at the effluent from CW with a removal efficiency of 75% and 100% for WSP and CW, respectively. Although progesterone removal efficiency was high, the amount released was still high enough to cause harm to aquatic organisms. Progesterone levels in the present study, although not extremely high, correspond to those associated with harmful effects in other studies. Therefore, this study suggests that anthropogenic activities conducted nearby the rivers should be strictly avoided to reduce the amount of progesterone to be released to the river.