3.1.3. Steroids

Land application of livestock manure can contribute to accumulation of steroid hormones [83] and veterinary pharmaceuticals. Very low concentrations of natural steroid hormones, such as estrone, 17α-estradiol, 17β-estradiol, estriol, testosterone, androstenedione and progesterone that occur in animal waste and wastewater have been documented as accumulating in soil [84]. Traces of steroid hormones have also been reported in groundwater [85] and surface water [86], and often in treated municipal wastewater [87–91]. Wastewater treatment plants are known to discharge these hormones into river water and also other recipients [92]. Laboratory experiments have suggested that traces of steroid hormones and pharmaceuticals can be taken up in crops [93] and recent studies of food

crops irrigated with treated municipal water have confirmed this can occur in the field. Further work is needed to understand the significance and impact of these chemicals in the environment and to human health [94], though at present, the reported concentrations are relatively low in comparison to other contaminants.
