岷沱江流域高氯酸盐污染分布特征及风险评估

Pollution Characteristics and Risk Assessment of Perchlorate in the Minjiang and Tuojiang River Basin

高氯酸盐能够干扰甲状腺对碘的吸收,抑制人体甲状腺激素的分泌而导致碘的缺乏,近年来引起了国内外研究学者的广泛关注。为了探究岷沱江流域高氯酸盐的水污染分布特征、生态风险和人体暴露风险状况,采用离子色谱-串联质谱法对岷沱江流域内采集的38个地表水和41份大米样品进行测定。结果表明:(1)高氯酸盐在采集的岷沱江流域地表水中检出率为100%,在岷江流域和沱江流域中的浓度范围分别为0.608~328.6μg/L和3.39~19.60μg/L,平均值分别为50.2μg/L和6.39μg/L,其中岷江支流青衣江以及沱江干流中人口和工业更为集中的成都段地表水中高氯酸盐浓度更高。(2)岷沱江流域大米中高氯酸盐的检出率分别为76.5%和91.7%,浓度范围分别为N.D.(低于检出限)~55.0μg/kg和N.D.~265.7μg/kg,沱江流域大米中高氯酸盐浓度均值高于岷江流域,岷江流域地表水和大米中高氯酸盐的含量呈显著正相关性。(3)对于岷沱江干流中的高氯酸盐,其水生态风险总体处于中低水平,但青衣江呈现高风险。(4)岷沱江流域居民摄入高氯酸盐的主要途径为饮用水,在平均暴露模式下,岷沱江流域内居民通过大米暴露于高氯酸盐的量未超过欧洲食品安全局建议值,基本安全;而通过饮用水暴露高氯酸盐的健康风险较高,特别是岷江流域存在严重超标现象,应引起重视。

Previous studies have documented that perchlorate competitively interferes with iodide absorption in the thyroid,inhibits the synthesis of thyroid hormone and leads to iodine deficiency,which has attracted extensive attentions at home and abroad in recent years.A total of 38 surface water and 41 rice samples were collected from the Minjiang and Tuojiang River basin in Sichuan Province to investigate perchlorate concentration levels,which was detected by ion chromatography-tandem mass spectrometry.Furthermore,ecological risk and human exposure to perchlorate via drinking water and rice consumption was evaluated.The results showed that the levels of perchlorate in the Minjiang and Tuojiang River ranged from 0.608 to 328.6μg/L(mean 50.2μg/L)and 3.39 to 19.60μg/L(mean 6.39μg/L),respectively,and perchlorate was found in 100%of surface wateracross all sites.Perchlorate was found at higher concentrations in the Qinyi River,which is a tributary of the Minjiang River and in Chengdu reaches of the Tuojiang River where the population and industry are relatively concentrated by contrast with the other points.The levels of perchlorate of rice in the Minjiang and Tuojiang River ranged from not detected(N.D.)to 55.0μg/kg and not detected(N.D.)to 265.7μg/kg,respectively,and with detection rates being 76.5%and 91.7%respectively.The median concentration of rice in the Tuojiang River was higher than in the Minjiang River.Pearson correlation analysis suggested that there was a significant positive correlation between surface water contamination and perchlorate pollution of rice in the Minjiang River basin.For perchlorate with available ecological data,the ecological risk of surface water in the Minjiang and Tuojiang mainstream was mainly at low and mediun levels,while presented a high risk in the Qingyi River.The human exposure assessments results indicated that drinking water was considered as the predominant pathway for human exposure to perchlorate.Under the average exposure mode,the amount of perchlorate exposure of rice in both river basin did not exceed the tolerated daily intake value of 0.3μg/kg BW established by European Food Safety Authority for healthy adults,which was basically safe.While the amount of perchlorate exposure via the consumption of drinking water in the Minjiang River basin posed a high healthy risk,especially seriously exceeding the standard for the Minjiang River basin,which should be paid more concern.