Residues of dioxins and PCBs in fat of growing pigs and broilers fed contaminated feed

To investigate the kinetics of PCBs and dioxins, 3 week old broilers and 3 month old pigs were fed with a 10-fold diluted feed from the Belgium crisis for one week, followed by a period on clean feed. In the case of broilers this resulted in levels for dioxins, non-ortho and mono-ortho PCBs in fat of 102, 84 and 216 ng TEQ/kg, summarized to 402 ng TEQ/kg. Total levels decreased to 217 and 109 ng TEQ/kg after 1 and 3 weeks on clean feed. Indicator PCB levels decreased from an initial 6.2 mg/kg fat to respectively 3.2 and 1.5 mg/kg. The ratio of indicator PCBs to dioxins TEQs was stable over this period. Levels in back fat of pigs at the end of the exposure period were 26, 15, 82 and 123 ng TEQ/kg for respectively dioxins, non-ortho PCBs, mono-ortho PCBs and the sum. Total TEQ levels decreased to respectively 95, 70, 40, 22 and 12 ng TEQ/kg after 1, 2, 4, 8 or 12 weeks on clean feed. After 12 weeks dioxin levels were around 1 ng TEQ/kg. Indicator PCB levels decreased from 3.48 mg/kg to 2.65, 2.01, 1.25, 0.76 and 0.45 mg/kg fat, again after 1, 2, 4, 8 or 12 weeks on clean feed. Levels of dioxins decreased more rapidly than those of indicator PCBs, also reflected by the ratio of indicator PCBs to dioxins, being 133,000 at the end of the exposure period and 357,000 after week 12. It is concluded that the use of indicator PCBs for dioxins, in the case of a combined exposure, is a safe alternative for screening and in the case of pigs results in an overestimation rather than underestimation of the dioxin levels.     

多食鞘氨醇杆菌共代谢降解五氯酚

研究了一株从活性污泥中分离得到的多食鞘氨醇杆菌(Sphingobacteriummultivorum)对五氯酚(PCP)的共代谢降解.比较了细菌分别以苯酚和葡萄糖为生长底物时对PCP的降解效果.结果表明,苯酚对细菌的生长有一定的抑制作用;葡萄糖支持细菌共代谢降解PCP,葡萄糖和非生长底物PCP之间不存在底物竞争抑制现象.蛋白质电泳结果表明,葡萄糖为生长底物时,PCP的降解酶是由PCP自身所诱导;GC-MS分析PCP共代谢降解中间产物时检测到苯酚的存在,说明在好氧降解情况下,PCP的共代谢降解可能也存在渐次脱氯生成苯酚并最终被矿化的过程.     

Fine particulate matter and cardiorespiratory health in China: A systematic review and meta-analysis of epidemiological studies

This review aimed to systematically summarize the epidemiological literature on the cardiorespiratory effects of PM_2.5 published during the 13^th Five-Year Plan period (2016–2020) in China. Original articles published between January 1, 2016 and June 30, 2021 were searched in PubMed, Web of Science, the China National Knowledge Internet Database and Wanfang Database. Random- or fixed-effects models were used to pool effect estimates where appropriate. Of 8558 records identified, 145 met the full eligibility criteria. A 10 µg/m³ increase in short-term PM_2.5 exposure was significantly associated with increases of 0.70%, 0.86%, 0.38% and 0.96% in cardiovascular mortality, respiratory mortality, cardiovascular morbidity, and respiratory morbidity, respectively. The specific diseases with significant associations included stroke, ischemic heart disease, heart failure, arrhythmia, chronic obstructive pulmonary disease, pneumonia and allergic rhinitis. The pooled estimates per 10 µg/m³ increase in long-term PM_2.5 exposure were 15.1%, 11.9% and 21.0% increases in cardiovascular, stroke and lung cancer mortality, and 17.4%, 11.0% and 4.88% increases in cardiovascular, hypertension and lung cancer incidence respectively. Adverse changes in blood pressure, heart rate variability, systemic inflammation, blood lipids, lung function and airway inflammation were observed for either short-term or long-term PM_2.5 exposure, or both. Collectively, we summarized representative exposure-response relationships between short- and long-term PM_2.5 exposure and a wide range of cardiorespiratory outcomes applicable to China. The magnitudes of estimates were generally smaller in short-term associations and comparable in long-term associations compared with those in developed countries. Our findings are helpful for future standard revisions and policy formulation. There are still some notable gaps that merit further investigation in China.     

Response of PM2.5-bound elemental species to emission variations and associated health risk assessment during the COVID-19 pandemic in a coastal megacity

The coronavirus (COVID-19) pandemic is disrupting the world from many aspects. In this study, the impact of emission variations on PM_2.5-bound elemental species and health risks associated to inhalation exposure has been analyzed based on real-time measurements at a remote coastal site in Shanghai during the pandemic. Most trace elemental species decreased significantly and displayed almost no diel peaks during the lockdown. After the lockdown, they rebounded rapidly, of which V and Ni even exceeded the levels before the lockdown, suggesting the recovery of both inland and shipping activities. Five sources were identified based on receptor modeling. Coal combustion accounted for more than 70% of the measured elemental concentrations before and during the lockdown. Shipping emissions, fugitive/mineral dust, and waste incineration all showed elevated contributions after the lockdown. The total non-carcinogenic risk (HQ) for the target elements exceeded the risk threshold for both children and adults with chloride as the predominant species contributing to HQ. Whereas, the total carcinogenic risk (TR) for adults was above the acceptable level and much higher than that for children. Waste incineration was the largest contributor to HQ, while manufacture processing and coal combustion were the main sources of TR. Lockdown control measures were beneficial for lowering the carcinogenic risk while unexpectedly increased the non-carcinogenic risk. From the perspective of health effects, priorities of control measures should be given to waste incineration, manufacture processing, and coal combustion. A balanced way should be reached between both lowering the levels of air pollutants and their health risks.     

Evaluation of risk and cost using an age-dependent unavailability modelling of test and maintenance for standby components

The improvement of safety in the process industries is related to assessment and reduction of risk in a cost-effective manner. This paper addresses the trade-off between risk and cost related to standby safety systems. An age-dependent unavailability model that integrates the effects of the test and maintenance (T&M) activities as well as component ageing is developed and represents the basis for calculating risk. The repair “same-as-new” process is considered regarding the T&M activities. Costs are expressed as a function of the selected risk measure. The time-averaged function of the selected risk measure is obtained from probabilistic safety assessment, i.e. the fault tree analysis. This function is further extended with inclusion of additional parameters related to T&M activities as well as ageing parameters related to component ageing. In that sense, a new model of system unavailability, incorporating component ageing and T&M costs, is presented. The testing strategy is also addressed. Sequential and staggered testings are compared. The developed approach is applied on a standard safety system in nuclear power plant although the method is applicable to standby safety systems that are tested and maintained in other industries as well. The results show that the risk-informed surveillance requirements differ from existing ones in technical specifications, which are deterministically based. Moreover, the presented approach achieves a significant reduction in system unavailability over a relatively small increase of total T&M costs.     

麦饭石吸附氨氮应用研究

主要研究麦饭石应用于吸附氨氮.采用静态吸附法测定麦饭石的吸附离子交换等温线,考察其吸附氨氮的规律,讨论溶液pH值和高温焙烧麦饭石对其吸附氨氮的影响,提出应用不同的溶液浸泡改性天然麦饭石,从而强化其对氨氮的吸附.研究结果表明,麦饭石对氨氮吸附主要由它的活性位和可交换离子决定,其吸附规律可以采用Freundlich等温方程...     

溶解性有机物(DOM)与区域土地利用的关系:基于三维荧光-平行因子分析(EEM-PARAFAC)

溶解性有机物（DOM）是水体质量的综合性指标,反映了流域内经济发展和治理保护等多方面因素,可为流域水体保护提供依据.本研究采集了宁波市4个不同城市化程度的区域内的河流样本,运用三维荧光结合平行因子分析法（EEM-PARAFAC）对水体中DOM进行解析,探讨了区域土地利用与DOM的关系.结果表明城市化在含量和组成两方面影响了流域水体中DOM的特征.城市区域（DOC=3.18 mg·L^-1）和城乡结合区域（DOC=7.45 mg·L^-1）水体中DOM的浓度远高于城市化程度较低的农村区域（DOC为2.16~2.62 mg·L^-1,ANOVA,P<0.001）.EEM-PARAFAC解析得到7个荧光组分,主要可归为类腐殖质和类蛋白质类物质.其中,城市区域DOM以类腐殖质物质为主,占比达到61.3%;而城乡结合区域由于受到更多的生活污水排放影响,类蛋白质物质的比例最高为59.4%;相比之下,农村区域虽然DOM浓度相对较低,但类腐殖质物质占比达63.6%~65.7%,面源污染是主要原因.主成分分析表明城市化发展对水质具有重要影响,在城市化初期污染主要来源于生活和工业污染源,当城市化到一定水平污染物更多来源于路面径流.本研究表明EEM-PARAFAC可以半定量辨析水体污染源,可为不同的区域水质恢复与治水策略制定提供针对性数据支撑.     

四斗朱水库蓝藻水华爆发成因分析及治理对策研究

作为饮用水源的小型水库四斗朱连续几年在早春即开始爆发严重束丝藻水华（属于蓝藻）。水质分析发现,四斗朱水库的水质参数如总氮（TN）、总磷（TP）、氨氮（NH4^＋-N）以及BOD和COD浓度并不高,但明显高于其上游的石门塘水库,这说明在四斗朱水库的集水区存在污染源。本文分析了在低营养盐浓度情况下四斗朱水库蓝藻水华爆发的原因,认为由于集水区内的农业、生活、水土淋失以及自然沉降等途径导致水库营养浓度升高。并由于未知营养、气温回升以及水库生态系统失衡等因素,导致蓝藻水华暴发。最后,提出了相应的综合治理对策。     

珠江口水域中华白海豚微量元素含量分析

对珠江口水域12头中华白海豚体内10种微量元素(As、Ba、Cd、Co、Cr、Cu、Ni、Pb、Zn、Hg)的含量进行测量.分析结果显示:受试样品中Zn元素含量最高,Cu、Hg次之,Co、Cr、Ni含量最低;肝脏和肾脏中微量元素含量较高,其余各组织器官中的分布不尽相同.分析认为珠江口水域中华白海豚受到一定程度的As、Hg、Cd、Pb污染.     

常态化疫情防控背景下区域应急医疗物资选址-分配模型*

在常态化疫情防控背景下,为避免本土病例造成区域不同需求主体防护物资短缺问题,构建最小化医院物资集散点需求未满足率加权和、最大化物资购买集中点分配公平性的储备库选址-分配模型,并基于某市相关数据,利用改进的非支配排序遗传算法（NSGA-Ⅱ）进行仿真研究。结果表明:某市应选择储备库数目为5,在物资分配时考虑物资防护等级要求,可减少医院物资集散点物资浪费,增加物资购买集中点获得量。