典型规模化养猪场废水中兽用抗生素污染特征与去除效率研究

采用固相萃取结合高效液相色谱/串联质谱方法,对苕溪流域某规模化养猪场排放的典型废水进行兽用抗生素污染检测.结果表明,废水中四环素、土霉素、金霉素和强力霉素等4种四环素类抗生素污染最为严重,最高单体污染浓度可达13.65×103ng·L-1.磺胺嘧啶、磺胺甲唑和磺胺二甲嘧啶等3种磺胺类物质也有一定的检出量,但以磺胺二甲嘧啶较为突出,最高检出量为675.4ng·L-1.氧氟沙星以及红霉素和罗红霉素等喹诺酮和大环内酯类抗生素除了原水有较低的检出量,其它废水均未检出.厌氧消化废水处理系统对废水中高浓度的抗生素具有明显的去除效果,但对低浓度的抗生素去除率较低.与欧盟水环境抗生素阈值(10ng·L-1)相比,排放水中的抗生素污染浓度对周边地表水环境的污染风险仍需要引起重视.通过饲料摄入途径估算养猪场排泄物抗生素含量,并与实测值比较,结果表明,饲料摄入并不是该养猪场兽用抗生素利用的主要方式,可能存在其它用药途径,需要在今后的畜禽养殖兽用抗生素的污染调查、风险估算和消减工艺研发中引起重视.     

WATER QUALITY CHARACTERISTICS OF STORM WATER FROM MAJOR LAND USES IN SOUTH FLORIDA1

ABSTRACT: Starting in 1998, a study was conducted to characterize storm water quality from predominant land use types in a coastal watershed along the south central coast of Florida, namely citrus, pasture, urban, natural wetland, row crop, dairy, and golf courses. Sixty‐three sampling sites were located at strategic points on drainage conveyances for each of seven specific land use areas. Runoff samples were collected following storm events that met defined rainfall criteria for a period of 30 months. Nitrogen (N), phosphorus (P), heavy metals, pesticides, and other water quality parameters were determined, and the results were analyzed to compare and characterize land uses as relative sources for these constituents in runoff. Results showed that runoff from most land use types had low dissolved oxygen concentration and that sediment and nutrient concentrations were closely related to land use, particularly to the amount of fertilizer applied in each land use. Among the eight heavy metals tested, copper was the most frequently detected and was mostly associated with runoff from citrus and golf course land uses. High levels of arsenic were also detected in golf course runoff. The most frequently detected pesticide was simazine from citrus. The information and methodologies presented may facilitate pollution source characterization and ecological restoration efforts.     

Incidental detection of premature centromere separation in amniocytes associated with a mild form of Roberts syndrome

Premature centromere separation (PCS) was detected in amniocytes after an amniocentesis was done because of markedly elevated maternal serum alpha-fetoprotein values in a healthy primiparous young woman. PCS has been associated with the Roberts-SC phocomelia syndrome (RS). By 23 weeks' gestation, ultrasonic evaluations did not reveal abnormal fetal development. The pregnancy continued and a male infant was born with mild manifestations of RS. PCS was confirmed in cord blood lymphocytes. This case illustrates that PCS, when detected in amniotic fluid cell cultures, requires a thorough evaluation.     

Characterization of precipitation in the background of atmospheric pollutants reduction in Guilin: Temporal variation and source apportionment

Rainfall samples were collected from three observation sites in Guilin from 2013 to 2017, and the chemical composition characteristics of precipitation and the contribution made by different ion sources were analyzed when atmospheric pollutants levels were reduced. The results showed that acid gas emissions and atmospheric pollutant concentrations continued to decline during the study period. However, the change in the volume-weighted mean p H at the three sites suggested that acid rain pollutio...