菊花茶中砷含量特征及砷健康风险评价

菊花茶是深受人们喜爱的一种饮品,但其干燥过程及加工工艺不当会造成菊花茶的重金属污染,尤其是和硫磺矿伴生的重金属砷。以市售菊花茶为研究对象,采用硝酸-双氧水消解体系,高压密闭消解系统和原子荧光光谱法分析测定了其中砷(As)含量,对典型超标菊花茶样品进行不同冲泡方式的筛选,确定其适宜的饮用方式,并根据我国绿色代用茶行业标准和WHO砷最大日允许摄入量(ADI)对菊花茶中砷的人体健康风险做出评价。结果表明,菊花茶中砷的含量范围在0.01～3.52mg·kg-1,91.1%的样品符合绿色代用茶的《中华人民共和国农业行业标准》(0.5mg·kg-1),其中砷含量最高的为药用祁菊花达3.52mg·kg-1,所有样品中超标的8个菊花茶样品种类分别为祁白菊(2个),杭白菊(2个),黄山贡菊(1个)和野菊花(1个),怀菊和药用祁菊各1个,75%的超标样品为散装饮品;选择超标的2个典型菊花茶样品(杭白菊和药用祁菊花)进行冲泡方式筛选,得出适宜的饮用方式为:用水茶质量比例为25∶1的开水清洗菊花茶5min,然后用开水冲泡5～20min再饮用。随菊花茶进入人体的最大日摄入量(极限值)为43.7～169μg·d-1,其占ADI(allowable daily intake)的比值范围在34.1%～132%,其中随药用祁菊花进入人体的As最大日摄入量与ADI的比值超过100%,这表明砷经菊花茶饮品摄入人体内所潜在的健康风险不容忽视。砷超标的菊花茶经过冲泡后饮用,砷的人体日摄入量13.1～36.3μg·d-1,其占ADI的比值范围在10.3%～28.4%。因此,经过洗茶后再冲泡饮用,砷的日摄入量显著降低(P<0.01),建议饮用菊花茶时洗1次茶后再冲泡饮用。

Arsenic Concentrations in Chrysanthemum Tea and Assessment of Arsenic Risk to Human

Chrysanthemum tea is a kind of popular tea around China. However, the improper dryness and producing processing of chrysanthemum might form the heavy-metals contamination, especially for arsenic combined with sulfur mines. Contents of As in samples of chrysanthemum tea from markets were investigated using HNO3/H2O2 mixture in the high pressure sealed container and measured using atomic fluorescence spectrometry (AFS). Moreover, screening of the optimum ways of making tea was conducted using the samples with As contents above the safety standard (standard of agriculture of the People's Republic of China: green food herb-tea). Allowable daily intake (ADI) standard value from Food and Agriculture Organization/World Health Organization (FAO/WHO) was used for preliminary assessment of As risk to human health. Results showed that As contents in chrysanthemum tea ranged from 0.01 to 3.52 mg·kg-1. As contents in 91.1% of samples was lower than the limited standard of green food herb-tea (0.5 mg·kg-1). The highest As content in all samples was 3.52 mg·kg-1 in Qi chrysanthemum for herbal medicine. Arsenic contents in 8 samples exceeded the standard of green food herb-tea, which are Qi white chrysanthemum (2 samples), Hangzhou chrysanthemum (2 samples), Huangshan chrysanthemum (1 sample), wild chrysanthemum (1 sample), Qi chrysanthemum for herbal medicine (1 sample) and chrysanthemum morifolium (1 sample). 75% of all samples with As contents above the safety standard are not packed. The samples of Hangzhou chrysanthemum and Qi chrysanthemum for herbal medicine with high As contents were used to study the brewing and drinking method. Specifically, boiling water at the mass ratio of water to tea of 25:1 was poured into cup for 5 min to wash the tea; then boiling water was added into cup and kept for 5 min to 20 min. Maximun daily intake of arsenic through chrysanthemum tea ranged from 43.7 to 169 μg·d-1, and the percentage of the daily intake of arsenic in chrysanthemum tea to ADI established by FAO/WHO was in the range of 34.1% to 132%. The maximum daily intake of arsenic via Qi chrysanthemum for herbal medicine to ADI was higher than 100%, indicating that arsenic in some types of chrysanthemum tea from markets had an unnegligible potential risk to human health. The daily intake of arsenic from chrysanthemum tea after being washed was in the range of 13.1 and 36.3 μg·d-1, and accordingly the percentage of the daily intake of arsenic in chrysanthemum tea to ADI was from 10.3%～28.4%. After chrysanthemum was washed, the level of arsenic daily intake decreased significantly ( P<0.01). Therefore, it is better to wash chrysanthemum once before drinking chrysanthemum tea.