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This study aimed to assess the extent of pollution of aquatic ecosystems by endocrine disrupting estrogens particularly the ethinylestradiol (EE2), estrone (E2) and estradiol (E1). The study was carried out in Morogoro urban and peri-urban areas. The main sources of fresh water for domestic uses, fishing and agricultural activities in the study areas including the Mindu dam catchment area, Ngerengere and Morogoro Rivers were assessed. The endocrine disrupting estrogens in water samples were identified and quantified using competitive Enzyme Linked Immunosorbent Assay (ELISA) kits. The recovery of estrogens in this study ranged from 65 to 90.22%, the range which is within the acceptable level. The levels of estrogens in Ngerengere River ranged from non-detectable levels to 0.68, 0.03 to 8.42 and 0.05 to 16.97 ng/L for EE2, E2 and E1, respectively. At Mindu Dam the levels ranged from 0.07 to 0.3 ng/L, 0.41 to 2.1 ng/L and 2.6 to 6.5 ng/L for EE2, E2 and E1 respectively. Furthermore, for Morogoro River the levels ranged from undetected to 0.92, 0.34 to 9.53 and 0.17 to 11.49 ng/L for EE2, E2 and E1 respectively. Mean concentrations in control samples and those in upstream and midstream of the rivers were comparable (p > 0.05). But the mean concentrations in downstream portions were significantly higher than those in control samples (p < 0.05). These concentrations however, were below those reported in other studies to cause harmful health effects. Hence, the extent of pollution was not significant enough to cause adverse health effects to aquatic organisms and human.

Endocrine disrupting estrogens are emerging contaminants in aquatic ecosystems and environment in general. There are no guidelines for routine monitoring of these chemicals, despite the existing evidences of their adverse health effect to living organisms at low concentrations. This study aimed at developing and validating an optimized HPLC-UV method for detection and quantification of estradiol and ethinylestradiol. Isocratic elution was used for separation and detection of ethinylestradiol and estradiol. The mobile phase was applied with A; water B; acetonitrile (50:50) at flow rate of 0.7mL/min and injection volume 10mL. The precision and accuracy of the method were within the acceptable range. Relative standard deviation of peak area for E2 ranged from 1.373 to 3.668%, and for EE2 ranged from 0.829 to 6.495 %. The percentage recovery for E2 ranged from 82.3 to 99.84 %, and for EE2 ranged from 84.6 to 103.52 %. Linearity of the method was realized at range of 2.5 to 50 ng/mL and 100 to 1000 ng/mL for both E2 and EE2. The linear regression coefficients were 0.9979 and 0.9973 for E2 whereas for EE2 were 0.9983 and 0.9976. Limit of detection were found to be 0.05 ng/mL and 0.08 ng/mL for E2 and EE2 respectively. The obtained limits of quantification were 0.18 and 0.28 ng/mL for E2 and EE2 respectively. In untreated sewage the concentrations of E2 and EE2 were 0.28 ng/ml and 0.18 ng/ml respectively. But in subsequent wastewater stabilization ponds the concentrations were below detection limit. Therefore, the optimized HPLC-UV method is suitable for detection and quantification of endocrine disrupting estrogens when a level of pollution is at least 0.15 ng/ml. At low extent of pollution would require use of the method in conjunction with ELISA technique.