基于荧光指纹的土门西沟小流域农业面源溯源研究

于2022—2023年采集密云水库的典型农业小流域土门西沟小流域内源样品构建指纹库,采集7、8月河道6个重点断面水样进行三维荧光光谱测定,通过平行因子分析解析小流域氮素来源。结果表明:研究区氮平均质量浓度为7.92 mg/L,主要形态为硝态氮;通过结合荧光激发发射矩阵与平行因子分析共解析出4种荧光组分,主要包括两种类腐殖质组分(C1、C2)及类蛋白组分(C3、C4),C1与农业有机肥施用有关,C2与堆肥有关,C3、C4主要来自农村生活污水或未分解的尿素化肥;研究区农村生活污水荧光指数平均值约为2.16,土壤浸提液荧光指数平均值约为1.83,农村生活污水在8月对农业面源约贡献35%;小流域丰水期水质波动主要与类腐殖质C1、C2组分相关,应对研究区有机肥带来的农业面源给予关注并加强管控。

Baseflow:Potential Pathway Underlying a High Nitrogen Concentra-tion in a Less-rainy WatershedTaking Chaohe River Basin of China as an Example

Baseflow is one of the major pathways of runoff in hilly areas,and its contributions to surface water resources and pollutant loads cannot be ignored.In this study,based on water quantity and quality data from 1988 to 2019 in hilly and low rainfall watersheds,we focused on the impact of long-term baseflow on nitrogen load using the load allocation based on the baseflow separation method.We also constructed a nitrogen balance model for the Chaohe River Basin of China from 2012 to 2021 to analyze the nitrogen accumulation in the basin.We used the baseflow nitrogen load lag analysis method to study the lag characteristics of the baseflow discharge process and analyzed the response and periodicity of baseflow nitrogen to precipitation and soil accumulation using time delay analysis.The res-ults showed that the contribution rate of baseflow nitrogen reached 69%and showed a slight increasing trend from 1988 to 2019.The ef-fects of changes in precipitation and nitrogen accumulation on the baseflow contribution was observed after 1-2 and 2 yr,respectively.After nitrogen accumulation,it entered the river channel through baseflow,which was already the main and continuous source of nitro-gen in rivers in hilly areas.

老年原发性甲状旁腺功能亢进症的外科诊治

目的分析老年原发性甲状旁腺功能亢进症(primary hyperparathyroidism,PHPT)患者的临床特点,外科治疗的安全性和有效性。方法对北京大学人民医院肝胆外科2000年1月至2020年12月接受手术的179例PHPT患者,按照手术时年龄是否超过60岁,分为老年组(n=51)和非老年组(n=128),回顾分析两组的症状、合并症、术前及术后血钙、血磷、血碱性磷酸酶(alkaline phosphatase,ALP)、血甲状旁腺激素(parathyroid hormone,PTH)、手术治愈率、并发症发生率等临床资料。计量资料对比采用t检验,计数资料对比及单因素分析采用χ^(2)检验,用Logistic回归(前进法)进行多因素分析。结果相对于非老年组,老年组非特异症状(包括乏力、头晕、食欲下降、记忆力下降等)占比较高(21.6%vs 8.6%,P=0.019),老年组术前血ALP水平较低[(163.4±229.8)U/L vs(325.9±449.2)U/L,P=0.016],老年组术前合并较高比例的高血压病(47.1%vs 21.1%,P=0.001)、糖尿病(31.4%vs 10.9%,P=0.001)、冠心病(13.7%vs 3.1%,P=0.013)、肿瘤(13.7%vs 3.9%,P=0.025)。分析发现非特异症状占比高的相关因素包括高血钙[OR=4.936(95%CI 1.126-21.637),P=0.034]和低血磷[OR=0.011(95%CI 0.000-0.650),P=0.030]。两组的治愈率(94.1%vs 96.1%,P=0.564)和并发症发生率(27.5%vs 44.5%,P=0.127)差异无统计学意义。结论对老年PHPT患者的手术治疗安全、有效,应更加重视老年PHPT患者的外科诊治。