青海黄南州某农业地区重金属铬的干湿沉降总量的采集与分析

Collection and analysis of total amount of dry and wet deposition of heavy metal chromium in an agricultural area of Huangnan Prefecture, Qinghai

在青海黄南某农业地区是青海省小麦和青稞的主要产区。为了解大气沉降中的铬对土地质量的影响,在该区域共布设了3个大气沉降的采样点。接尘缸采用内径为15cm、高为30cm的圆筒形陶瓷缸。采取了一年的大气沉降样品,用具有橡皮头的玻璃棒把缸壁擦干净,将全部溶液和尘粒全部转移至500mL塑料容器中。将样品称取质量后放置在105℃烘箱中烘干,称取总重量,用手工磨样方式制备成100目待分析样品。样品经过微波消解,用电感耦合等离子体光谱测试。为验证准确度,同时加入土壤国家一级标准物质GBW07446(GSS-17),测试值为23.4,在其不确定度范围内;测试6次的相对标准偏差RSD为1.25%,加标回收率为97.4%至102.8%之间。铬的大气沉降总质量为20ng,日平均沉降量为0.03μg·(m2·d)-1。

In an agricultural area of Huangnan, Qinghai, Qinghai is the main producing area of wheat and highland barley. In order to understand the effect of chromium in atmospheric deposition on land quality, three sampling points for atmospheric settlement were set up in this area. A cylinder shaped ceramic cylinder with an in-ner diameter of 15cm and a height of 30cm is adopted for the dust collecting cylinder. A year＇s atmospheric sedi- mentation sample was used to clean the cylinder wall with a glass rod with a rubber head, and all the solution and dust particles were transferred to the 500mL plastic container. The samples were weighed and placed in a drying oven at 105℃, and the total weight was weighed. The sample was prepared by hand grinding method into 100 mesh samples. Samples were digested by microwave and tested by inductively coupled plasma spectrometry. In order to verify the accuracy, the standard substance GBW07446 （GSS-17） of the soil national first grade was added, the lest value was 23.4, in the range of uncertainty, the relative standard deviation of the test 6 times was 1.25%, and the recovery rate of the added standard was 97.4% to 102.8%. The total mass of chromium deposition is 0.02p, g and the average daily settlement is 0.03μg·（m^2·d）^-l.