黄河流域宁夏段沉积物氟形态生物有效性及其对地表水氟污染的影响

Bioavailability of Fluoride in Sediments and Its Effect on Surface Water Fluoride Pollution in Ningxia Section of Yellow River Basin

摘要:

为探明黄河流域宁夏段沉积物氟生物有效性，于2019、2021年春（4月）、夏（7月）、秋（10月）对黄河流域宁夏段99个点位进行6次采样。将99个点位划分为8个水系（黄河干流（S1）、清水河（S2）、苦水河（S3）、卫宁段黄河北岸排水沟（S4）、卫宁段黄河南岸排水沟（S5）、青石段黄河西岸排水沟（S6）、青石段黄河东岸排水沟（S7）、城市景观河湖（S8）），分析沉积物氟的时空分布特征，评估沉积物氟的生态风险，并探讨其对地表水氟污染的影响。结果表明：黄河流域宁夏段沉积物水溶态氟（Ws-F）、可交换态氟（Ex-F）、总氟（T-F）含量均值分别为9.42、3.23、517mg/kg，潜在生态风险生物有效态氟含量评价模型（ERbc）和潜在生态风险氟有效性因子评价模型（ERbf）的评价结果更能反映实际生态风险，S3、S2和S7沉积物Ws-F、Ex-F、T-F含量和氟生态风险均具有较高水平，S1均较低。Ws-F是对地表水F-含量起直接影响的重要因子，T-F通过转化为Ws-F间接影响地表水F-含量。S3、S2和S7沉积物氟化物的强释放能力促进水体氟含量升高，应作为重点管控区域。S1稀释作用、S6沉积物氟化物的弱释放能力降低了水体氟含量。

Abstract:

In the spring (April), summer (July), and autumn (October) of 2019 and 2021, samples were collected six times from 99 points in the Ningxia section of the Yellow River Basin. These 99 points were categorized into eight hydrological networks: the main stream of the Yellow River (S1), Qingshui River (S2), Kushui River (S3), drainage ditch on the north bank of the Yellow River in the Weining section (S4), drainage ditch on the south bank of the Yellow River in the Weining section (S5), drainage ditch on the west bank of the Yellow River in the Qingshi section (S6), drainage ditch on the east bank of the Yellow River in the Qingshi section (S7), and urban landscape rivers and lakes (S8). The spatial and temporal distribution characteristics of fluorine in sediments were analyzed, the ecological risk of sedimentary fluorine was evaluated, and its impact on fluorine pollution in surface water was discussed. The results showed that the average contents of water-soluble fluorine (Ws-F), exchangeable fluorine (Ex-F), total fluorine (T-F) in sediments from the Ningxia section of the Yellow River Basin were 9.42mg/kg, 3.23mg/kg, and 517mg/kg, respectively. The evaluation results of ERbc and ERbf can better reflect the actual ecological risk. The contents of Ws-F, Ex-F, and T-F in the sediments of S3, S2 and S7 and the ecological risk of fluorine were all high, while those of S1 were low. Ws-F was an important factor that directly affected the F- content in surface water. T-F indirectly affected the F- content of surface water by transforming into Ws-F. The strong release capacity of fluoride in sediments of S3, S2 and S7 promoted the increase of fluoride content in surface water, which should be taken as the key control area. The dilution effect of S1 and the weak release ability of fluoride in sediments of S6 reduced the fluoride content in surface water.