The use of simulated rainfall to study the discharge process and the influence factors of urban surface runoff pollution loads.

An understanding of the characteristics of pollutants on impervious surfaces is essential to estimate pollution loads and to design methods to minimize the impacts of pollutants on the environment. In this study, simulated rainfall equipment was constructed to investigate the pollutant discharge process and the influence factors of urban surface runoff (USR). The results indicated that concentrations of total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD) appeared to be higher in the early period and then decreased gradually with rainfall duration until finally stabilized. The capacity and particle size of surface dust, rainfall intensity and urban surface slopes affected runoff pollution loads to a variable extent. The loads of TP, TN and COD showed a positive relationship with the surface dust capacity, whereas the maximum TSS load appeared when the surface dust was 0.0317 g·cm⁻². Smaller particle sizes (<0.125 mm) of surface dust generated high TN, TP and COD loads. Increases in rainfall intensity and surface slope enhanced the pollution carrying capacity of runoff, leading to higher pollution loads. Knowledge of the influence factors could assist in the management of USR pollution loads.

Pretreatment of dialyzer with high-dose vitamin C reduces oxidative stress of patients withhemodialysis / 中华全科医师杂志

Sixty patients who had hemodialysis over half year were randomly divided into 3 groups with 20 cases in each group:group A received conventional hemodialysis,group B received hemodialysis with oral administration of compound danshen (salvia miltiorrhiza bunge) tablets and vitamin E,group C had the same treatment as group B but the dialyzer was pretreated with solution containing 5 g vitamin C ; 20 healthy adults served as normal controls. Serum levels of advanced oxidation protein products (AOPP) and superoxide dismutase (SOD) were measured in all groups.The levels of AOPP in groups A,B,C were higher and SOD levels were lower than those of normal controls ( all P ＜ 0.01 ).The levels of AOPP in groups B,C were lower and SOD were higher than those in group A at the same time points (P ＜0.01 ).The levels of AOPP in group C were lower and SOD were higher than those in group B at the same time points (P ＜0.0l ).The results suggest that pretreatment of the dialyzer with high dose vitamin C plus vitamin E and compound danshen tablets can alleviate oxidative stress in patients with maintaining hemodialysis.