环境健康风险评价中我国居民暴露参数探讨

暴露参数是人体暴露和健康风险评价中的关键性参数,根据我国居民人群的基本体征参数和相关调查统计数据,在借鉴和参考了美国环境保护署(US EPA)建立暴露参数的方法学基础上,探讨了我国居民呼吸、饮食、皮肤等的暴露参数. 结果表明:我国居民呼吸速率为5.71～19.02 m3/d,18岁以下人群各种活动强度下男性和女性的呼吸速率几乎一样,而18～60岁的男性呼吸速率明显大于女性;我国成年人饮食量为1 176.3 g/d,主要食用米、面及其制品,分别占总饮食量的23%和13%;我国成年男性的皮肤表面积为1.697 m2,成年女性为1.531 m2;我国成年男性平均体质量为62.70 kg,成年女性平均体质量为54.40 kg;我国居民的各种暴露参数与美国相差2.5%～33.3%,若在同等条件下参考国外暴露参数开展暴露和健康风险评价可能带来较大的偏差,开展全国范围内系统的暴露参数调查研究工作迫在眉睫.      

湖南省大气污染物排放与人体暴露水平研究

基于吸入因子概念,建立了污染物排放造成的人体暴露的计算方法.应用CALPUFF长距离扩散模型和多元回归分析对湖南省17个电厂(24个排放源)的一次细颗粒(PM_2.5)、SO₂和NO_x排放进行了研究.结果表明,在半径500km范围内,PM_2.5、SO₄^2-和NO₃^-的平均吸入因子分别为9.73×10^-6、2.39×10^-6和2.47×10^-6.回归分析表明,PM_2.5的吸入因子与烟囱高度及人口数量有很高的相关性(R²=0.83),SO₄^2--吸入因子与烟囱高度无关,与人口数量有较好的相关性(R²=0.64),而NO₃的吸入因子与烟囱高度、人口数量的相关性较高(R²=0.74).基于回归方程和人口分布地图,对湖南省污染排放的吸入因子进行区划,得到的吸入因子等值图反映了人口分布对吸入因子的影响,可用于对该地区的排放源造成的健康影响进行快速评价.     

稀土元素日允许摄入限量的差异与农用安全性讨论

比较不同时期提出的稀土元素日允许摄入量(AD I)的差异性发现,随着研究的深入,近期提出的AD I值明显低于早期的AD I值,反映了人们对稀土元素毒性效应有了进一步的认识。根据农产品中稀土元素残留量及其可通过食物链为人们所摄入的现状,分析了稀土农用、稀土厂“三废”对生态环境的污染影响以及潜在的食品安全性问题。     

Polybrominated diphenyl ethers in food and associated human daily intake assessment considering bioaccessibility measured by simulated gastrointestinal digestion

The concentrations of PBDEs in 299 vegetable and animal-based food samples of 31 species, collected in Shanghai, China, and the bioaccessibility of PBDEs in part of the samples were determined. The PBDE concentrations ranged from 0 to 1245.4 pg g⁻¹ with animal-based food containing more PBDEs than vegetables. The bioaccessibility of PBDEs, determined by a method simulating human gastrointestinal digestion process, were from 2.6% to 39.9% in vegetables, and from 5.2% to 105.3% in animal-based food. For animal-based food, good correlations were observed between the bioaccessibility of PBDEs and the fat content, thus the fat content in animal-based food was able to be used to estimate the bioaccessibility of PBDEs. The total daily intake of PBDEs via ingestion of vegetables and animal-based food for an average Shanghai resident was estimated as 13 235.7 and 13 668.0 pg d⁻¹, respectively, but the amounts available for human absorption were reduced to 2674.4 and 4316.6 pg d⁻¹ after the PBDE bioaccessibility was considered. Finally, the contributions of different food groups to the total daily intake of PBDEs were evaluated. The results revealed that, when not considering the bioaccessibility of PBDEs, vegetables were the leading contributor (49.2%), followed by fish (34.0%). However, the sequence was reversed after the PBDE bioaccessibility was taken into account. The results indicated that human exposure to PBDEs via food ingestion might have been significantly overestimated and the exposure assessment could be misleading if the bioaccessibility of PBDEs was not considered.     

PCDD/PCDF,chlorinated pesticides and PAH in Chinese teas

Four samples of Chinese tea (two green teas, and two brick teas) were analyzed for their concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF), chlorinated pesticides and PAH. The infusions prepared from these teas were also analyzed for PCDD/PCDF. The levels of DDT and its metabolites in tea leaves were within the safety limit of 0.2 mg/kg. Rather high levels of total PAH were obtained in brick tea (1048–1162 mg/kg), when compared with green tea (497–517 mg/kg). In terms of PCDD/PCDF, the concentrations of green tea and brick tea differed by a factor of 16, while the concentrations of all infusions were within a factor of 2. The dioxin concentrations in green tea leaves can be explained through uptake of atmospheric PCDD/PCDF. The higher concentrations in the brick tea leaves are due the longer exposure time, and to certain extent, the use of old leaves, branches and roots when making the tea, and additional components such as soil particulates through contamination. Certain Chinese populations drinking a large amount of brick tea (>3 l per day) indicated that individuals of these populations consume more tea than Europeans or North Americans result in a comparably higher intake of PCDD/PCDF. Tea consumption can attribute to up to 10% of the TDI recommended by WHO (only PCDD/PCDF considered, no PCB analyzed).     

以河床井水为应急水源的可行性研究

为解决城市水源地突发污染事故引起的自来水厂断水问题,提出了以河床井水代替受污染河水作为应急水源的应急预案,在取水口附近的河床打一口水井,当城市水源地发生突发污染事故时,关闭取水头水阀,开启水井水阀,以河床井水作为应急水源,并通过模拟试验验证了其可行性.结果表明,在细沙体积分数为40％的土壤条件下,原水苯胺质量浓度分别为952 mg/L、781 mg/L、580 mg/L、452mg/L、352mg/L、182mg/L的试验中,出水苯胺质量浓度开始超标的时间随土壤渗透系数减小而延迟,与原水苯胺质量浓度无关.当土壤渗透系数为1.94×10-5～ 3.64×10-5 cm/s时,出水苯胺质量浓度开始超标的时间为84～ 144h,以河床井水作为应急水源可以避免由河水突发污染引起的84h内的自来水厂断水事故.土壤对苯胺的吸附量仅占原水中苯胺含量的14.95％～ 2.86％,其对出水苯胺质量浓度开始超标的时间的影响可以忽略,出水苯胺开始出现的时间主要由土壤渗透系数决定.出水苯胺最大质量浓度随原水苯胺质量浓度增大呈线性增加,线性方程为y =0.4979x-3.7029,R2=0.9775.研究表明,以河床井水作为应急水源,能够有效地降低城市因突发污染事故而引起的自来水厂断水的可能性.     

Estimate of zearalenone exposure through the intake of white and brown rice in the Korean population

Rice samples (n = 482) harvested for 2010–2012 in South Korea were analyzed for zearalenone content by high-performance liquid chromatography and fluorescence detection. The exposure of the Korean populations was assessed by a deterministic approach. Because the proportion of non-detectable results was >80% in white rice but less than <60% in brown rice, the zearalenone levels for white rice were reported as 0.52 µg kg^?1 as lower bound and 2.54 µg kg^?1 as upper bound, while for brown rice the middle bound value was 13.9 µg kg^?1. The average dietary intake of zearalenone from white and brown rice by the Korean population was estimated to be 1.5 ng kg^?1 body weight (bw) day^?1 each. For heavy consumers, the average intakes were 18.5 and 10.1 ng kg^?1 bw day^?1, respectively. The age groups with the highest zearalenone intake were 1–2-year-old children for white rice and 3–6-year-old children for brown rice. Overall, the dietary exposure of the Korean population to zearalenone from white and brown rice was found to be lower than the provisional maximum tolerable daily intake of 0.5 μg kg^?1 bw day^?1.     

Realistic approach of pesticide residues and French consumer exposure within fruit & vegetable intake

The increase of fruit and vegetable (F&V) intake contributes to the prevention of chronic diseases, but could also significantly increase pesticide exposure and may thus be of health concern. Following a previous pesticide exposure assessment study, the present study was carried out to determine actual levels of pesticides within 400 g of F&V intake and to evaluate consumer risk. Forty-three Active Substances (AS) exceeding 10 % of the Acceptable Daily Intake (ADI) in balanced menus established for our previous theoretical study were considered. Fifty-six pooled food samples were analyzed: 28 fruit samples and 28 vegetable samples. Pesticide values were compared to Maximum Residue Levels (MRL) and to the “toxicological credit” derived from ADI. It was observed that 23 out of the 43 retained AS were never detected, 5 were detected both in F&V samples, 12 only in fruits and 3 only in vegetables. The most frequently detected AS were carbendazim, iprodione and dithiocarbamates. When detected, AS were more frequently found in fruit samples (74 %) than in vegetable samples (26 %). A maximum of 3 AS were detected at once in a given sample. Overall, we observed 8 and 14 overruns of the MRL in 1204 measures in pooled vegetable and fruit samples, respectively (0.7 % and 1.2 % of cases, respectively). Chronic exposure for adults was the highest for dithiocarbamates but did not exceed 23.7 % of the ADI in F&V. It was concluded that raising both F&V consumption up to 400 g/day (～5 F&V/day) according to recommendations of the national health and nutrition plan, does not induce pesticide overexposure and should not represent a risk for the consumer.     

Lead and cadmium bioaccumulation in fowl eggs depending on different food concentrations

Cadmium and lead bioaccumulation in eggs from four groups of laying hens was studied. The birds were fed on foods containing different quantities of cadmium and lead, exceeding the official technological standards for three of the groups. Bioaccumulation was studied using two criteria: coefficient of biological intake (CBI), which is the ratio between the concentration of the chemical element in a unit of dry biomass and its fodder concentration, and Klarck of concentration /Kc/ ‐ a dynamic value which includes both the fodder and water concentrations of the elements needed for acquiring a unit of biomass. For the high cadmium and lead concentrations, dissipation of the studied elements in the egg mass was established with lower values of both CBI and Kc.     

Degradation dynamics,residues and risk assessment of Dufulin enantiomers in corn plants and corn by LC/MS/MS

ABSTRACT

The degradation dynamics and terminal residues of dufulin enantiomers were investigated in two typical corn plants. A convenient and precise chiral method by high-performance liquid chromatography coupled with tandem triple quadrupole mass spectrometry (HPLC/MS/MS) using a Chiralpak IC column was developed and validated for measuring dufulin enantiomers in corn plants and corn. The two enantiomers of dufulin quickly dissipated in the corn plant, and no noticeable stereoselectivity was observed during degradation or in the final residues. After 30% rac-dufulin wettable powder with a 1- to 1.5-fold dose of the recommended value was sprayed two to three times on corn plants, the residue levels of S-(+)-dufulin and R-(-)-dufulin in corn from both sites were lower than or equal to 0.0520 mg kg^–1 on days 7, 14 and 21 after the last application. The dietary risk assessment indicated that dufulin did not exhibit obvious dietary health risks in corn samples when good agricultural practices were implemented. The findings from this study may be used to better understand the chiral profiles of dufulin in the environment and the effect of dufulin residues in corn on health.