呼伦湖水体氟化物演变特征及其影响因素

为识别呼伦湖水体中氟化物的演变趋势，揭示呼伦湖水体氟化物浓度畸高的原因，于2015—2020年对呼伦湖入湖河流、湖周地下水、湖泊水体中氟化物（以F-计）浓度进行了详细调查，并结合2005—2014年历史数据分析呼伦湖水体中氟化物浓度的影响因素.结果表明:2018—2019年，呼伦湖全湖水体氟化物浓度平均值在2.27~2.42 mg/L之间，年均值为2.36 mg/L，4个季节平均值之间无显著差异，但空间分布差异显著，在春季、夏季和秋季均表现为四周低、中间高的分布趋势，冬季则相反.3条主要入湖河流克鲁伦河、乌尔逊河和呼伦沟河水体中氟化物浓度显著低于湖体，分别为（1.14±0.36）（0.84±0.14）和（0.33±0.08）mg/L，氟化物入湖通量分别为236.41、396.31和301.29 t/a，地下水和入湖河流输入是呼伦湖水体氟化物的主要来源.呼伦湖水体中氟化物浓度主要在特殊气候地理条件引起的高自然本底环境下，受pH、湖体蓄水量和冰封作用的共同影响.研究显示，入湖河流、地下水等输入的氟化物在强蒸发作用下富集浓缩且缺少氟化物出湖途径是造成呼伦湖水体氟化物浓度畸高的根本原因. 

Characteristics and Influencing Factors of Fluoride in Lake Water of Hulun Lake

In order to identify the evolution trend and reveal the reasons for the abnormally high fluoride concentration in Hulun Lake, field surveys of the fluoride concentration in the inflow rivers, surrounding groundwater and lake water were conducted from 2015 to 2019. Together with the historical fluoride concentration in Hulun Lake from 2005 to 2014, the factors influencing the fluoride concentration in Hulun Lake were analyzed. Based on the data from the whole-lake surveys conducted in 4 different seasons of 2018-2019, the whole-lake average fluoride concentration in Hulun Lake was 2.27-2.42 mg/L, with an annual average of 2.36 mg/L, and there was no significant difference between the average concentrations of the four seasons. However, the lake water fluoride concentration showed different spatial distribution patterns in the four seasons. While the fluoride concentration in the areas near the lakeshore was lower than in the lake center in spring, summer and autumn, the fluoride concentration was higher near the lakeshore in winter. The fluoride concentrations in the water of the three major inflow rivers of Hulun Lake were (1.14±0.36), (0.84±0.14) and (0.33±0.08)mg/L, which were significantly lower than that of the lake water. The fluoride fluxes from the three major rivers into the lake were 236.41, 396.31 and 301.29 t/a, respectively. Inflow rivers and groundwater discharge were the main input sources of fluoride in Hulun Lake. The fluoride concentration in the water of Hulun Lake was mainly resulted from the high natural background environment caused by the special climatic and geographical conditions, and it was also affected by pH, lake water volume and icing. Accumulation and concentration of the fluoride from the inflow rivers, groundwater discharge and other sources in the lake under the influence of the high evaporation and a lack of fluoride output are the primary causes of the high fluoride concentration in the Hulun Lake water.