Preliminary aquatic life criteria development and ecological risk assessment of ammonia in seven major river basins in China

Ammonia is one of the basin indices which are nation-controlled in the waterenvironmental management. In order to assess the differences of ammonia criteria indifferent basins, 7 major basins are used for the study object, including Songhua River,Liaohe River, Haihe River, Yellow River, Huaihe River, Yangtze River and ZhujiangRiver, referring the water environmental criteria technology of the United StatesEnvironmental Protection Agency, based on the effects of water characteristics on theecotoxicity of ammonia, and in summer and non-summer situation, aquatic life criteriais derived for ammonia. The results showed that: (a) The differences between thecriteria values in different basins and different seasons were significant. The differencesbetween the criteria values in different basins were greater than 6 times, while those indifferent seasons in the same basin were greater than 2 times. (b) The summer acuteand chronic criteria for Huaihe River were 0.37 mg/L and 0.06 mg/L while thenon-summer values were 0.81 mg/L and 0.15 mg/L. Both the summer and thenon-summer values were lowest in all of the seven basins. (c) The preliminaryassessment of Ammonia exposure ecological risk indicated that was the lowest inZhujiang River, and it was much lower in Songhua River, Liaohe River and YangtzeRiver, and was higher in Yellow River, and the highest in both Haihe River and HuaiheRiver. Haihe River has 7 sections while 2 in high risk, and Huaihe River has 27 sectionswhile sixteen in high risk. According to the differences of the criteria values for ammoniain seven basins in different seasons and difference of ammonia ecological riskassessment, it is suggested that it should be managed by different policies.

基于综合评分法和风险商值法筛选黄河流域特征污染物及风险污染物

随着工业化进程的加快和城市化的发展,大量污染物排入黄河流域,并被频繁检出,威胁生态系统和人类健康。为获取潜在生态环境风险污染物,该研究通过调研2000年1月1日−2022年12月31日Web of Science(WoS)和中国知网(CNKI)数据库中黄河流域已报道的288篇污染物相关文献,使用多指标综合评分法筛选黄河流域的特征污染物,采用风险商值法获取水样和沉积物中的风险污染物。结果表明:①黄河流域共检出10类144种污染物,采用9类共13个筛选指标构建多指标综合评分法,对污染物各项指标进行评分,然后进行K-means聚类分析,按得分高低分为Ⅰ~Ⅵ级,选取得分较高的33种Ⅰ级和Ⅱ级高分值污染物作为黄河流域特征污染物,包括12种有机氯农药、10种多环芳烃、10种多氯联苯和1种邻苯二甲酸酯。②水样污染物浓度和沉积物含量前5种都是重金属、有机氯农药、邻苯二甲酸酯、多环芳烃以及药品和个人护理产品,而且二者顺序完全一致,且多数污染物的浓度之间存在显著相关性。③根据风险最大化原则,使用风险商值法(RQ)分别对水样和沉积物进行风险评估,将RQ≥0.1的污染物列为风险污染物,水样中共筛选出21种风险污染物,其中RQ≥1的高风险污染物有5种,包括硒、铅、苯并[a,h]蒽、苯并[a]蒽和邻苯二甲酸二丁酯。④沉积物中共筛选出19种风险污染物,其中有13种高风险污染物,包括8种多环芳烃(芘、蒽、荧蒽、苊、萘、芴、苯并[a]蒽、苯并[a,h]蒽)、4种重金属(汞、铅、硒、砷)和1种邻苯二甲酸酯(邻苯二甲酸二丁酯)。该研究对相关部门拟定黄河流域污染物监测方案和管控措施有重要参考意义。

Assessment of Metal Accumulation in the Vegetables and Associated Health Risk in the Upper-Most Ganga-Yamuna Doab Region, India

The present study indicates the status of metal contamination in the vegetables/crops grown in the upper most Ganga-Yamuna doab region of India and associated health risk. Commonly grown vegetables and crops were sampled and analyzed for the metal contamination. Maximum concentration (mg/kg) of Cd and Cr, was observed in Radish (7.6) and Cabbage (56.24) respectively, whereas maximum concentration of Pb, Ni and Zn was observed in the edible parts of Mustard plant (95.4, 58.6, 756.43 respectively). Bio-concentration factor (BCF) value indicated the transfer level of metal from soil to crop;indicated high transfer value of Cd in Radish followed by cabbage and spinach. Considerably high BCF value was observed in the Mustard (8.13), Cabbage (4.18) and radish (3.07) for Zn contamination. Estimated daily intake (EDI) and Hazard quotient (HQ) or Non-carcinogenic health risk was calculated using the USEPA method. The result revealed that the metal intake and associated health risk were considerably high in the children population in comparison to the adult population.

Mineral Uptake of Heavy Metals by Some Marine Organisms along the Limbe Coastline in Cameroon and Health Risk Assessment

This study aimed at investigating the content of heavy metals in some marine organisms of the Cameroon Atlantic coast and assessing the health risk due to their consumption by the population. Nine fish and one shrimp species were collected for this study. These fish species were Ethmolosa fimbriata, Drepane africana, Dentex moroccanus, Arius latiscotatus, Scarus hoefleri, Cynoglossus browni, Sardinella madorensis, Pseudotolithus elongatus, Pseudotolithus typus. The shrimp species was Macrobranchium macrobranchium. The elements investigated in this study were: Fe, Co, Cu, Cd and Pb. For seven fish species it was found that the concentration of heavy metals followed the order Fe > Co > Cd > Cu > Pb. For most fish species the Target Hazard Quotient (THQ) value calculated showed the following trend Cd > Co > Pb > Fe ≥ Cu. Cadmium was found to be the main contributor to health risk that may result from the consumption of the fish species under study. The THQ for this element was in the range 0.7 - 1.2 while the Target Cancer Risk (TR) due to ingestion of this metal was in the range (3 × 10-4 - 6 × 10-4). These values are slightly above the threshold limits established for both carcinogenic and non carcinogenic risks by the United States, Environmental Protection Agency. The estimated weekly intake of cadmium due to consumption of some fishes under study was greater or equal to the Provisional Tolerable Weekly Intake (PTWI) determined by Food and Agriculture Organization/World Health Organization.

Health Risk Assessment of Heavy Metals in the Water of the LoutétéRiver, Mfouati District, Southeast Congo

The overall objective of this study was to assess the health risk of water in the Loutété River contaminated with heavy metals. Six surface water samples were collected during the dry season (October 2014). The physico-chemical parameters (pH, electrical conductivity, total dissolved salts) were measured using a HANNA brand device. The values of these physico-chemical parameters are below the WHO standards. The concentrations of heavy metals Cr, Cu, Fe, Pb, Zn and Mn were determined by ICP-OES. These obtained in (μg/L) are in the range: Cr (0.08 - 5.8);Cu (0.6 - 14.5);Fe (0.2 - 386.05);Pb (1.02 - 370.09);Zn (8.02 - 248.7) and Mn (37.1 - 328.08). These concentrations are below the WHO drinking water guideline value in all samples for Cr, Cu, Mn and Zn, 50, 2000, 400 and 3000 μg/L respectively. Concentrations of As, Fe and Pb exceeded the WHO guideline value for drinking water at the following stations: S1 for arsenic, S4 for iron, and for Pb at all stations except S5. The health risk assessment for adults due to ingestion exposure gave HQing. values < 1 for the following heavy metals: Cr, Cu, Fe, Mn, Zn, except for Arsenic and Lead. The hazard quotient calculated by dermal contact (HQ derm) in the waters of the river Loutété, showed that HQ derm < 1 for all heavy metals in all stations. For children, the dermal contact hazard quotient HQ derm < 1 for all heavy metals As, Fe, Cu, Zn, Mn, Cr and Pb. With the exception of station S4, we observed that HQ > 1 for lead. In the case of ingestion, HQing. < 1 for the heavy metals Cr, Cu, Zn, Mn, with the exception of the following metals Arsenic, Lead and Iron.

Health Risk Assessment on Selected Essential and Non-Essential Elements in Food Crops Grown in Kibera Slum, Nairobi-Kenya

Peri-urban agriculture of food crops is practiced in many slum areas in developing countries. This often uses waste water whose levels of essential and non-essential elements are largely unknown but would be feared to contaminate soils, consequently exposing man to associated health risks. Inhabitants in Kibera slum, Nairobi City practice these growing kales, amaranthus, arrowroots, and spinach. Health risk assessment was done using daily intake of metals (DIM), target hazard quotient (THQ) and incremental lifetime cancer risk (ILCR). Atomic absorption spectroscopy was employed for elemental analysis. The levels of essential elements ranged as follows;Mn 91.04 - 374.44, Mg 261.28 - 532.96, Fe 350.74 - 1273.68, and Zn 1.18 - 6.3 μg/g per dry weight were found to be below the recommended limits by FAO/WHO. Non-essential elements ranged as follows;Cr 1.15 - 4.32 and Pb 0.14 - 0.91 μg/g above the EU recommendation. DIM of Fe 5.81 - 27.61 and Mn 1.97 - 8.12 μg/g is above the recommended daily intake amounts. THQ values for Mn and Fe were more than unit. THQ values for non-essential elements were generally below unit. ILCR showed that from lead alone 73 people (0.043% of 0.17M residents) are likely to develop cancer. There are foreseen health risks associated with consumption of food crops grown in Kibera slum that requires immediate address.

儿童软糖中合成着色剂的含量测定及健康风险评估

目的 检测市售8种儿童软糖中所添加的5种合成着色剂(柠檬黄、日落黄、诱惑红、胭脂红、亮蓝)的含量,并对其进行健康风险评估。方法 采用GB 5009.35—2016《食品安全国家标准食品中合成着色剂的测定》中的高效液相色谱法(high performance liquid chromatography,HPLC)进行检测,样品采用水浴温热溶解、聚酰胺吸附提取、HPLC检测,以甲醇/乙酸铵为流动相,紫外检测波长为254 nm,根据保留时间定性,基于外标峰面积法定量。运用靶标危害系数(target hazard quotient,THQ)法对儿童软糖中所添加的合成着色剂进行健康风险评估。结果 5种合成着色剂的含量在0.384~7.875 mg/kg之间,标准曲线均具有较好的线性关系(r~2>0.99),各着色剂的检出限(limits of detection,LODs)为0.0203~0.1600 mg/kg,定量限(limits of quantification,LOQs)为0.0614~0.4836 mg/kg,加标回收率大于95%,5种合成着色剂的THQ及总THQ值(total target hazard quotient,TTHQ)均小于1,对儿童健康无明显风险。结论 通过儿童软糖摄取的合成着色剂的健康风险很小,与儿童软糖的小包装、食用量少有关,还需要配合家长对儿童糖果摄入的合理管理。本研究为儿童软糖的购买和食用提供了科学建议。

我国典型流域地表水中抗生素污染现状及生态风险评价

为了解我国典型流域地表水中抗生素污染及其生态风险现状,通过收集历史文献数据,采用风险熵值法对抗生素污染进行了生态风险评价。结果表明:①辽河流域大环内酯类(MLs)抗生素检出浓度最高(201.88 ng/L),太湖流域磺胺类(SAs)抗生素检出浓度最高(22.70 ng/L),黄河下游、海河流域、长江上游、珠江下游检出浓度最高的抗生素为喹诺酮类(QNs),检出浓度分别为123.89、248.66、108.20、113.00 ng/L;②辽河流域、黄河下游、海河流域、太湖流域、长江上游、珠江下游旱季抗生素检出浓度分别为雨季的1.76、1.64、1.48、4.59、7.36、1.73倍;③6大流域水体中,抗生素对藻类均呈现出中高风险,其中珠江下游的风险最高(6.06),其次是长江上游(5.61)、海河流域(4.74)、黄河下游(3.76)、辽河流域(辽宁省内地区)(2.83),太湖流域的风险最低(0.76)。本研究为进一步了解和评估我国各流域水环境的抗生素污染及其生态风险提供了一定的科学参考。

氟调酸在我国典型城市污水处理厂中的浓度分布及排放

氟调酸(fluorotelomer carboxylic acids,FTCAs)是全氟烷基羧酸(perfluoroalkyl carboxylates,PFCAs)的前体物,同时也是替代加工助剂.本研究应用固相萃取-液相色谱-三重四极杆质谱仪联用的检测分析方法,探究了中国5个城市9座城市污水处理厂进水、二沉池出水、三级处理出水和污泥中6种FTCAs和12种PFCAs的分布及排放特征.FTCAs在城市污水处理厂进水中的浓度为0.52—2.00×10^(3) ng·L^(-1),受纳工业废水的城市污水处理厂进水中FTCAs的浓度高于其他主要受纳生活污水的城市污水处理厂,表明工业废水的排放会影响城市污水处理厂中FTCAs的浓度水平.生物处理工艺对FTCAs和PFCAs的去除率分别为43%—93%和-40%—69%.∑FTCAs在三级处理出水及污泥中的总排放量为13.6 g·d^(-1),6:2 FTCA和8:2 FTCA为主要的组成物质.三级处理出水中FTCAs及PFCAs的风险商分析表明三级处理出水中6:2 FTCA、PFHxA、PFOA、PFNA和PFDA可能对鱼类存在潜在风险.本研究为我国城市污水处理厂中新污染物的管控提供了数据基础.

东海三门湾主要海产品中典型重金属累积状况

为探究我国东海三门湾主要养殖海产品重金属累积状况,评估当地沿海居民因海产品摄入导致的重金属健康风险,并以此了解海产品中重金属的累积特异性,本研究于2022年10月—12月选取三门湾养殖场进行取样,共取76份样本,包含10个品种,分析样品中总砷、无机砷、总镉、总铅和总汞这几种典型重金属含量,采用单因子污染指数评估这10种海产品受重金属污染的情况,应用目标危害系数及复合危害系数评估当地沿海居民长期食用海产品的健康风险,同时对海产品中无机砷的赋存形态展开讨论。结果表明仅部分虾蛄、梭子蟹中镉含量高于限量值(3.0 mg·kg^(-1)),所有样品中的无机砷、铅和汞的含量均低于限量值。不同种类的海产品对重金属累积存在显著差异,这10种海产品除受到镉不同程度的污染外,另外3种重金属污染均处于正常水平,当地沿海居民长期摄入这10种海产品由重金属引起的健康风险属于低关注级别。每种海产品中的无机砷含量低于总砷含量的5%,且与总砷含量之间表现出弱相关性。本研究可为了解三门湾养殖海产品的重金属污染状况及为评价当地沿海居民食用三门湾养殖海产品引起的重金属暴露风险提供科学依据,同时也可为了解海产品中重金属累积特异性和重金属安全限量值的研究提供基础科学信息。

潮白河再生水补给区地表水中邻苯二甲酸酯生态风险评估

邻苯二甲酸酯(PAEs)是一种常用的增塑剂,同时也是一类内分泌干扰物,对生物的生殖和发育具有潜在影响。为了评估潮白河再生水补给区地表水中PAEs的浓度水平和生态风险,根据近6年补给区地表水PAEs监测数据,分析了地表水中PAEs浓度变化,使用物种敏感性分布法(SSD)建立了5种PAEs的长期水质基准,推导出其长期水质基准值(LWQC),应用风险商值法确定了PAEs的生态风险。结果显示:补给区地表水中6种PAEs中DBP年均检出浓度最高,为3822.45 ng/L,BBP年均检出浓度最低,仅为24.72 ng/L,且无论是在枯水期还是丰水期,地表水中PAEs单体均以DEHP和DBP为主;基于急性、慢性毒性数据建立的DMP、DEP、DBP、BBP和DEHP的长期水质基准STWQC与LWQC值依次为373.4μg/L、205.46μg/L、4.8μg/L、12.04μg/L、3.15μg/L和1168.21μg/L、179.57μg/L、10.72μg/L、15.05μg/L、26.73μg/L;总体而言,DMP、DEP、BBP具有较低的生态风险,而DBP和DEHP具有潜在的生态风险,可能对地表水生物造成不利影响,应予以重视。

陕西省市售茶叶的铅污染状况及健康风险评估

目的探究陕西省市售茶叶中铅污染情况并评估饮茶的健康风险。方法在陕西省9个市的茶叶经营单位随机抽样采集了305份样品。使用电感耦合等离子体质谱法测定茶叶中的铅含量,并用单项污染指数法评价茶叶铅污染情况。计算经饮茶途径的铅的每日摄入量,并用蒙特卡洛模拟全面展现饮茶途径的铅暴露状况。利用靶标危害商评估饮茶途径铅暴露的健康风险。结果陕西省市售茶叶铅检出率为99.02%,铅含量范围为0.02~3.05mg/kg,所有样品的铅含量均符合GB2762—2017《食品安全国家标准食品中污染物限量》。不同种类、不同茶区的茶叶铅含量存在显著性差异(P<0.05)。黑茶铅含量最高,其次是青茶、绿茶,红茶的铅含量最低。西南茶区的茶叶中铅含量处于较高水平。饮茶途径铅暴露的最大靶标危害商为4.25×10^(–2),远小于1。结论陕西省市售茶叶铅检出率高,但铅含量均符合GB2762—2017。饮茶途径的铅暴露不会造成明显的健康风险,应重点关注黑茶与青茶的铅含量。本研究结果可为市售茶叶监管和健康风险控制提供科学依据。

千岛湖表层沉积物中有机磷酸酯赋存特征、来源解析及生态风险研究

本研究以16种有机磷酸酯(organophosphate esters,OPEs)为研究对象,采用分散固相萃取结合超高效液相色谱-三重四极杆质谱的方法,分析了千岛湖26个表层沉积物中OPEs的赋存特征、污染来源和生态风险.结果表明12种OPEs在千岛湖表层沉积物中广泛存在,ΣOPEs平均浓度为8.8 ng·g^(−1)干重(dry weight,dw),范围为2.6—28.5 ng·g^(−1)dw.TEHP、TCEP、TEP和TCIPP是沉积物OPEs中的主要组分,平均浓度分别为4.2、1.7、1.1、0.9 ng·g^(−1)dw.千岛湖街口至小金山段沉积物中OPEs总浓度(11.2—28.5 ng·g^(−1)dw)和烷基型OPEs总浓度(8.5—24.8 ng·g^(−1)dw)显著高于其他区域表层沉积物(ΣOPEs:2.6—12.2 ng·g^(−1)dw;Σalkyl-OPEs:0.9—7.1 ng·g^(−1)dw),表明街口至小金山段沉积物中OPEs的污染程度明显高于其他区域.主成分分析进一步表明街口至小金山段沉积物中OPEs主要受到新安江上游来水输入的影响.此外,在千岛湖镇附近识别到人类聚居地和船舶码头等潜在点源.千岛湖所有点位沉积物中OPEs的风险商(risk quotient,RQ<0.1)较低,表明对生态环境的风险水平较低.

武汉市14种市售淡水鱼类中砷和汞的污染特征及膳食暴露风险评估

目的研究武汉市市售水产品中常见的14种淡水鱼类(草鱼、团头鲂、白鲢、鳙鱼、鲫鱼、鲤鱼、翘嘴鲌、鲈鱼、鳜鱼、青鱼、乌鳢、胡子鲇、斑点叉尾鮰、黄颡鱼)背肌和腹肌中的重金属含量特征并评价其膳食暴露风险。方法采用电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)对样品不同部位中的砷(As)、汞(Hg)两种重金属含量进行测定,通过单因子污染指数(single factor pollution index,Pi)评估了14种鱼类中As和Hg的污染水平、目标风险系数(target hazard quotients,THQ)评估了鱼类中的As和Hg对于成人、儿童的膳食暴露风险,并且对样品不同部位中As和Hg的含量进行了相关性分析。结果14种鱼类中,As在背肌和腹肌中的含量范围分别为0.002~0.312 mg/kg、0.001~0.440 mg/kg,Hg在背肌和腹肌中的含量范围分别为0.003~0.104 mg/kg、0.006~0.189 mg/kg。Pi测定结果显示,不同品种的水产品均具有一定程度的污染。通过计算THQ并综合考量无机As占总As的含量,所有样品的THQ值均小于1。依据相关性分析,发现在草鱼和胡子鲇的背肌中,As和Hg的含量具有显著相关性;在鲤鱼的腹肌中,As和Hg的含量具有相关性。结论本研究所采集的样品中,均未发现As和Hg超标,且样品内As和Hg污染均处于较低水平,长期食用这些鱼肉样品不会对人体健康造成潜在威胁。

鄱阳湖流域农村小微湿地氨氮生态风险评估

以鄱阳湖流域农村小微湿地为研究对象,通过对多个农村小微湿地的调查,得到该水体中氨氮浓度及分布特征,并使用商值法和安全阈值法2种生态风险评价方法对氨氮数据进行分析。研究结果表明:鄱阳湖流域农村小微湿地夏季氨氮浓度在0.18~2.75mg/L之间,且26.1%的样点超出地表III类水标准;进贤县氨氮超标率最高,星子县超标率最低。整理分析夏季氨氮数据,商值法评价结果显示南昌县小微湿地水体氨氮对水生生物有短期的生态风险,安全阈值法综合评价结果显示夏天小微湿地均具有较高的风险性。研究结果可为农村小微湿地生态风险管理和新农村建设提供参考。

消费者膳食中二氧化硫残留的累积性风险评估

【目的】明确不同食物源中的二氧化硫残留累积暴露风险,为硫磺或亚硫酸盐类(以二氧化硫残留计)在水果、蔬菜等产品中的使用及其二氧化硫残留限量的制定提供科学依据。【方法】采集生产及流通环节的各类食品(包括农产品),共计3 299个样品,参照GB/T 5009.34—2003《食品中亚硫酸盐的测定》方法进行二氧化硫残留量检测。结合文献资料中淀粉、酒类、食用菌及藻类罐头等408个样品的二氧化硫残留数据,基于残留均值、人均消费量及体重数据,采用点评估方法评估中国不同人群的二氧化硫累积性膳食暴露风险。【结果】在27种食品中,腌渍的蔬菜、蔬菜罐头(仅限竹笋、酸菜)、水果干类及食用淀粉的残留均值分别为148.92、147.36、191.21和41.57 mg·kg^(-1),均超过了GB 2760—2014《食品安全国家标准食品添加剂使用标准》中允许的最大使用量,其中蔬菜罐头(仅限竹笋和酸菜)的残留均值是允许使用量的2.9倍,水果干类是1.9倍,腌渍的蔬菜是1.5倍,食用淀粉是1.4倍。通过风险评估可知,由于这4类食品的消费量较低,其风险程度均在人体可接受范围内;尽管蔬菜中二氧化硫的膳食暴露风险商高于其他食物类别,但其风险商仅为0.124,仍小于1,处于安全水平,不会对消费者产生健康风险;从平均残留水平得到的风险商来看,不同年龄段人群的风险商均小于1,而P95和P97.5位点值时,2—3岁、4—6岁、7—10岁和11—13岁4个年龄组的膳食风险商已大于或近似于1,说明在该年龄段,二氧化硫的膳食风险对健康造成了一定威胁。【结论】建议消费腌渍蔬菜、蔬菜罐头(仅限竹笋、酸菜)、水果干类及食用淀粉的人群适当控制这4类食品的摄入量;对二氧化硫的膳食高风险人群(2—13岁)应控制其饮食中二氧化硫的摄入量,尤其是减少腌菜类食品的消费量,降低膳食风险;建议对未做明确使用规定的农产品尤其是部分新鲜蔬菜,开展二氧化硫残留的安全性再评价,结合产业需求、产品本底等客观因素,系统性修订二氧化硫的限量标准或增加食品添加剂的使用范围。

长江水系武汉段典型有机氯农药的生态风险评价

通过采集并测定长江水系武汉段30个不同样点水样中3种典型有机氯农药(OCPs)(p,p′-DDT、艾氏剂、γ-HCH)的浓度,依据OCPs对44～68种水生生物的无可见效应浓度(NOEC),分别应用商值法、概率密度函数重叠面积和联合概率曲线3种风险评价方法对长江水系武汉段p,p′-DDT、γ-HCH、艾氏剂的生态风险进行了评价.结果表明,3种风险评价方法得到的结果基本一致,长江水系武汉段3种OCPs残留均存在一定的生态风险.其中,p,p′-DDT的生态风险最大,艾氏剂次之,γ-HCH的生态风险最小.此外,对风险评价过程中存在的不确定性进行了分析,通过对不同方法及评价结果的分析表明,联合概率曲线方法更适合于长江水系武汉段OCPs的风险表征.

七大流域氨氮水生生物水质基准与生态风险评估初探

氨氮是我国流域水环境管理的国控指标之一,为评估不同流域的氨氮基准差异性,以七大流域(松花江流域、辽河流域、海河流域、黄河流域、淮河流域、长江流域和珠江流域)为研究对象,基于水质参数对氨氮毒性的影响,借鉴US EPA(美国国家环境保护局)水环境基准技术方法,分夏季和非夏季2种情况推算了各流域氨氮水生生物基准值.结果显示:1流域和季节的不同导致氨氮基准值的差异均很明显,不同流域的氨氮基准值差异可超过6倍,同一流域不同季节的氨氮基准值差异可超过2倍.2淮河流域夏季和非夏季氨氮基准值均为最低,夏季氨氮急、慢性基准值分别为0.37和0.06 mg/L,非夏季分别为0.81和0.15mg/L.3氨氮暴露生态风险初步评估结果表明,珠江流域风险较小;松花江流域、辽河流域、长江流域次之;黄河流域风险较大;海河流域和淮河流域风险最大,海河7个断面中有2个存在高风险,淮河27个断面中16个存在高风险.根据各流域不同季节氨氮基准值及氨氮暴露生态风险的差异,建议对不同流域、不同季节实行差异化管理.

豆芽中6-苄基腺嘌呤残留的膳食风险评估

近年来,我国相关监管部门、专业人士及社会舆论对豆芽中6-苄基腺嘌呤（6-BA）残留是否会给消费者带来膳食健康风险出现了很大争议,但一直未见有系统的风险评估研究报告。为明确豆芽中6-BA残留的膳食暴露风险,在充分收集市场豆芽残留监测数据和中国裁判文书中豆芽残留数据的基础上,采用点评估方法评估了我国不同人群的6-BA膳食暴露风险。评估结果显示：近年我国各类人群的6-BA膳食暴露（情景Ⅰ）风险商（RQ）平均值为0.001,97.5百分位点值为0.001~0.003;在豆芽制发中普遍使用6-BA的情况下（情景Ⅱ）,其风险商平均值为0.001~0.003,97.5百分位点值为0.003~0.006;在极端高残留假设下（情景Ⅲ）的风险商平均值为0.011~0.025,97.5百分位点值为0.025~0.055;在果蔬中普遍残留假设下（情景Ⅳ）的风险商平均值为0.007~0.020,97.5百分位点值为0.012~0.031。可见,豆芽中6-BA的膳食暴露风险非常低,远未达到健康关注水平。6-BA在豆芽生产中规范使用具有技术必要性和高安全性,建议重新允许使用,同时制定其使用规范和残留限量要求,建议其残留限量（MRL）值可设为0.2 mg/kg。