Steroids are excreted from humans and animals and discharged with wastewaters into the environment, resulting in potential adverse effects on organisms. Based on the excretion rates from different groups of humans and animals, we estimated the emissions of seven steroids (estrone (E1), 17β-estradiol (E2), estriol (E3), testosterone (T), androsterone (A), progesterone (P), and cortisol (C)) in 58 river basins of whole China, and simulated their multimedia fate by using a level III fugacity multimedia model. The results showed that higher emission densities for the steroids were found in the river basins of east China than in west China. This distribution was found to be generally similar to the distribution of Gross Domestic Product (GDP) across China. E3, A and P displayed higher emission densities than the other steroids in most of the river basins. The total excretion of steroids by humans and animals in China was estimated to be 3069 t/yr. The excretion of steroids from animals was two times larger than that from humans. After various treatments, the total emission of steroids was reduced to 2486 t/yr, of which more than 80% was discharged into the water compartment. The predicted concentrations in water were within an order of magnitude of the measured concentrations available in the literature. Owing to wastewater irrigation, more steroid mass loadings in agricultural soil were found in the basins of Haihe River and Huaihe River in comparison with the other river basins. To the best of our knowledge, this is the first report on the emissions and multimedia fate of seven steroids in the river basins of China.
Figure 5. The total steroid emission map of China. (A) The total amount of all the steroids for each basin with the unit of t/yr; (B) the emission density for each basin, with the unit of kg/m2·yr.
References:
(1) Zhang QQ, Zhao JL, Ying GG, Liu YS, Pan CG (2014) Emission estimation and multimedia fate modeling of seven steroids at the river basin scale in China. Environmental Science & Technology 48, 7982-7992.
(2) Liu S, Ying GG, Zhou LJ, Zhang RQ, Chen ZF, Lai HJ (2012) Steroids in a typical swine farm and their release into the environment. Water Research 46, 3754-3768.
Liu S, Ying GG, Zhang RQ, Zhou LJ, Lai HJ, Chen ZF (2012) Fate and occurrence of steroids in swine and dairy cattle farms with different farming scales and wastes disposal systems. Environmental Pollution 170, 190-201.