Variability in pesticides residues the US experience

The evolution of US Environmental Protection Agency's (EPA) process for estimating potential health risks from pesticide residues in or on food is examined in light of changes in US Legislation and the variability of residue data and assumptions used to estimate dietary exposure. In the 86 years since enactment of the Insecticide Act, pesticide laws have become progressively more health-based. Passage of the 1996 Food Quality Protection Act (FQPA) requires EPA to place particular emphasis on assessing potential risk from pesticides to infants and children. Primary factors affecting the actual pesticide residues in food include frequency of application, percentage of crop treated, and the interval from treatment to harvest. Primary factors affecting the estimated pesticide residues in food include the source of the residue data, calculation techniques for non-detected residues, and the availability of data reflecting post-harvest treatments. Risk assessors must thoroughly consider these factors when assessing dietary risk to pesticides. Risk managers will need to consider these factors as a means of mitigating dietary risk from pesticides.     

Fundamental changes to EPA's research enterprise: the path forward

Environmental protection in the United States has reached a critical juncture. It has become clear that to address the complex and interrelated environmental challenges we face, we must augment our traditional approaches. The scientific community must build upon its deep understanding of risk assessment, risk management, and reductionism with tools, technologies, insights and approaches to pursue sustainability. The U.S. Environmental Protection Agency (EPA) has recognized this need for systemic change by implementing a new research paradigm called "The Path Forward." This paper outlines the principles of the Path Forward and the actions taken since 2010 to align EPA's research efforts with the goal of sustainability.     

Development of the method and U.S. normalization database for Life Cycle Impact Assessment and sustainability metrics

Normalization is an optional step within Life Cycle Impact Assessment (LCIA) that may be used to assist in the interpretation of life cycle inventory data as well as life cycle impact assessment results. Normalization transforms the magnitude of LCI and LCIA results into relative contribution by substance and life cycle impact category. Normalization thus can significantly influence LCA-based decisions when tradeoffs exist. The U. S. Environmental Protection Agency (EPA) has developed a normalization database based on the spatial scale of the 48 continental U.S. states, Hawaii, Alaska, the District of Columbia, and Puerto Rico with a one-year reference time frame. Data within the normalization database were compiled based on the impact methodologies and lists of stressors used in TRACI-the EPA's Tool for the Reduction and Assessment of Chemical and other environmental Impacts. The new normalization database published within this article may be used for LCIA case studies within the United States, and can be used to assist in the further development of a global normalization database. The underlying data analyzed for the development of this database are included to allow the development of normalization data consistent with other impact assessment methodologies as well.     

食品中化学物累积风险评估方法及应用

食品中存在的各种污染物、农药和添加剂等化学物可能会通过多种机制的联合作用对人体形成累积暴露,但传统的风险评估方法多以单一化学物暴露为基础。近年来,化学物累积暴露形成的健康风险受到越来越多的重视,一些累积风险评估方法,如类别每日可耐受摄入量(TDI)、危害指数(HI)、相对效能因子(RPF)、生理毒代动力学(PBTK)模型等也逐渐发展起来。本文对这些方法的特点及其应用进行了讨论。     

Establishing policy relevant background (PRB) ozone concentrations in the United States

Policy Relevant Background (PRB) ozone concentrations are defined by the United States (U.S.) Environmental Protection Agency (EPA) as those concentrations that would occur in the U.S. in the absence of anthropogenic emissions in continental North America (i.e., the U.S, Canada, and Mexico). Estimates of PRB ozone have had an important role historically in the EPA's human health and welfare risk analyses used in establishing National Ambient Air Quality Standards (NAAQS). The margin of safety for the protection of public health in the ozone rulemaking process has been established from human health risks calculated based on PRB ozone estimates. Sensitivity analyses conducted by the EPA have illustrated that changing estimates of PRB ozone concentrations have a progressively greater impact on estimates of mortality risk as more stringent standards are considered. As defined by the EPA, PRB ozone is a model construct, but it is informed by measurements at relatively remote monitoring sites (RRMS). This review examines the current understanding of PRB ozone, based on both model predictions and measurements at RRMS, and provides recommendations for improving the definition and determination of PRB ozone.     

The application of tris buffer and copper sulfate for the preservation of phenylurea pesticides analyzed using U.S. EPA method 532 in the UCMR Survey

A high performance liquid chromatographic method was developed to meetthe U.S. Environmental Protection Agency's (EPA) Unregulated Contaminant Monitoring Rule (UCMR) Survey need for the analysis of phenylurea pesticides in drinking waters. Many of these phenylurea compounds were demonstrated to degrade rapidly in the presence of the residual chlorine disinfectant in drinking waters. This degradation was halted by the addition of a tris buffer, which was initially chosen to optimize the sample pH prior to extraction. Copper sulfate was found to prevent the regrowth of microorganisms in surface waters, which was observed upon dechlorination. Tris buffer provided the additional benefit of keeping the copper sulfate preservative in solution even in groundwater matrices that caused precipitation of copper in its absence. A C18 solid phase, in cartridge or disk form, was used to efficiently extract target compounds from the preserved drinking water matrices. A 21-day storage stability study, together with precision and accuracy studies, demonstrated thatthis method had suitable sensitivity, selectivity, accuracy, precision, and ruggedness for use in the EPA's UCMR drinking water occurrence survey.     

Temporal changes in U.S. benzene emissions inferred from atmospheric measurements

The 1990 Clean Air Act Amendments required the United States Environmental Protection Agency (U.S. EPA) to enact stricter regulations aimed at reducing benzene emissions. In an effort to determine whether these new regulations have been successful in reducing atmospheric benzene concentrations, we have evaluated benzene-to-acetylene ratios from data sets spanning nearlythree decades, collected during several field studies and from the U.S. EPA's Photochemical Assessment Monitoring Station (PAMS) network. The field-study data indicate a decrease in benzene relative to acetylene of approximately 40% from 1994 to 2002. This corresponds to a decrease in benzene alone of approximately 56% over the same period. In contrast, the PAMS data exhibit high interannual variability with no discernible trend. This discrepancy is attributed to measurement problems in the PAMS data sets.     

Expert judgment assessment of the mortality impact of changes in ambient fine particulate matter in the U.S

In this paper, we present findings from a multiyear expert judgment study that comprehensively characterizes uncertainty in estimates of mortality reductions associated with decreases in fine particulate matter (PM(2.5)) in the U.S. Appropriate characterization of uncertainty is critical because mortality-related benefits represent up to 90% of the monetized benefits reported in the Environmental Protection Agency's (EPA's) analyses of proposed air regulations. Numerous epidemiological and toxicological studies have evaluated the PM(2.5)-mortality association and investigated issues that may contribute to uncertainty in the concentration-response (C-R) function, such as exposure misclassification and potential confounding from other pollutant exposures. EPA's current uncertainty analysis methods rely largely on standard errors in published studies. However, no one study can capture the full suite of issues that arise in quantifying the C-R relationship. Therefore, EPA has applied state-of-the-art expert judgment elicitation techniques to develop probabilistic uncertainty distributions that reflect the broader array of uncertainties in the C-R relationship. These distributions, elicited from 12 of the world's leading experts on this issue, suggest both potentially larger central estimates of mortality reductions for decreases in long-term PM(2.5) exposure in the U.S. and a wider distribution of uncertainty than currently employed in EPA analyses.     

Cumulative risk assessment of the intake of organophosphorus and carbamate pesticides in the Danish diet

The aim of the study is to evaluate the potential cumulative effects of organophosphorus and carbamate pesticides that act through a common mechanism of toxicity, and to assess the long- and short-term risks for the Danish population. The intake estimates are based on dietary intake data collected in the Danish nation-wide food consumption survey in 1995. The pesticide data are based on the Danish pesticide residue-monitoring programme from 1996-2001. The amount of 35 organophosphorus pesticides and carbamates were included in the cumulative risk assessment. Processing factors, such as reduction of pesticide levels by rinsing and peeling, were applied in the exposure assessment. The "Toxicity Equivalence Factor" (TEF) approach was used to normalise the toxicity of the different organophosphorus and carbamate pesticides. Cumulative chronic exposure of organophosphorus and carbamates pesticides via fruit, vegetables and cereals is for adults 0.8-2% of the Acceptable Daily Intake (ADI) in chlorpyrifos equivalents, and 0.03-11% of the ADI in methamidophos equivalents; and for children 2-5% of the ADI in the chlorpyrifos equivalents, and 0.07-27% of the ADI in methamidophos equivalents. Neither Acute Reference Dose (ARfD) nor ADI was exceeded for any of the compounds studied. The results indicate that the Danish population is neither exposed to any cumulative chronic risk, nor at risk of acute exposure, from consumption of organophosphorus and carbamate pesticides from fruit, vegetables and cereals.     

Comprehensive environmental assessment: a meta-assessment approach

With growing calls for changes in the field of risk assessment, improved systematic approaches for addressing environmental issues with greater transparency and stakeholder engagement are needed to ensure sustainable trade-offs. Here we describe the comprehensive environmental assessment (CEA) approach as a holistic way to manage complex information and to structure input from diverse stakeholder perspectives to support environmental decision-making for the near- and long-term. We further note how CEA builds upon and incorporates other available tools and approaches, describe its current application at the U.S. Environmental Protection Agency, and point out how it could be extended in evaluating a major issue such as the sustainability of biofuels.     

Development of U.S. EPA method 527 for the analysis of selected pesticides and flame retardants in the UCMR survey

Method 527 was developed to address the occurrence monitoring needs of the U.S. Environmental Protection Agency (EPA) under its second unregulated contaminant monitoring rule (UCMR 2). This method includes a wide range of semivolatile organic contaminants, including pesticides that were deferred during the first UCMR, flame retardants, and pyrethroid pesticides. This paper discusses the rationale for selection and inclusion of the various contaminants included in Method 527 and describes the challenges associated with developing analytical methods that will be used for the occurrence monitoring of such a diverse group of organic molecules. Method 527 employs solid-phase extraction with analysis by gas chromatography/ mass spectrometry (GC/MS). The final method preservation scheme requires the storage of samples in amber bottles buffered at pH 3.8 using citric acid to prevent degradation from acid-catalyzed hydrolysis and from UV light. Citric acid is also an effective antimicrobial reagent, preventing this mode of loss during storage. Ethylenediaminetetraacetic acid (EDTA) is added to remove transition metals such as copper, which was determined to degrade target analytes upon storage. Finally, free available chlorine (FAC), which is present in many finished waters and found to degrade a number of the targets, is removed using ascorbic acid. The final method meets all of the EPA UCMR survey requirements for sample storage, precision, accuracy, and sensitivity and will be proposed for use under the UCMR 2.     

Brief survey of EPA standard-setting and health assessment

The Environmental Protection Agency (EPA) promulgates standards for air pollutants and drinking water contaminants, as part of its mandate to protect public health and welfare. The Agency also assesses the health risks associated with hundreds of chemical substances, often developing quantitative toxicity and cancer potency benchmarks. This article compares EPA standards and benchmark values to those of other countries and other agencies. This includes the national ambient air quality standards (NAAQS), the national primary drinking water regulations (NPDWR), and benchmark values from the Integrated Risk Information System (IRIS). Results show that the NAAQS are generally comparable to or less strict than the air quality standards of other countries and international organizations. The NPDWR tend to be less strict than the water quality standards of other countries for inorganic chemicals, and they are more strict about as often as they are less strict for organic chemicals. Reference values for toxicity and cancer potency derived in EPA health assessments posted in the IRIS database are less stringentthan those of other agencies about as often as they are more stringent, and they are often identical. Revisions to these values more often than not made them less stringent. These results suggest that EPA's standards and quantitative health assessments are not out of line with those of other agencies and other countries.     

Pesticide residues and acute risk assessment the US EPA approach

The US Environmental Protection Agency (EPA) assesses acute dietary exposure to pesticide residues using a tiered approach, proceeding from conservative to more refined assumptions as the risk management situation requires. Toxicity and food residue data used by EPA in assessing acute dietary risk are obtained from studies submitted by chemical companies in support of pesticide registration and tolerance setting. The primary source of food consumption data used by EPA in acute dietary risk assessments is the Continuing Survey of Food Intakes by Individuals (CSFII) 1989-1991.     

Using radon risk to motivate smoking reduction: evaluation of written materials and brief telephone counselling

OBJECTIVE: Radon and cigarette smoking have synergistic effects on lung cancer, even when radon concentrations are relatively low. Working through an electric utility company, we sought to reach smoking households with low radon concentrations and motivate smoking cessation or prohibiting smoking in the home. DESIGN: Eligible homes (n = 714) were randomised to receive: (1) the Environmental Protection Agency's (EPA's) "A citizen's guide to radon"; (2) a specially developed pamphlet; or (3) that pamphlet plus brief telephone counselling. PROCEDURE: Utility company "bill stuffers" offered free radon test kits to smoking households. All households received radon test results with an explanatory cover letter. Both the specially developed pamphlet and the telephone counselling emphasised that smoking cessation or prohibiting smoking in the home were the optimal risk reduction strategies. Households were followed up at 3 and 12 months after receiving materials. RESULTS: The specially developed pamphlet and the EPA guide yielded similar outcomes. There was a non-significant trend for telephone counselling to produce greater sustained quitting than the specially developed pamphlet, and phone counselling led to significantly more new household smoking bans. CONCLUSIONS: Working through a public utility company is an efficient way to reach smoking households, and brief telephone counselling is a promising method for promoting household smoking bans and cessation in homes alerted to the risk posed by the combination of radon and smoking.     

云南省新鲜蔬菜中11种有机磷农药残留情况分析及慢性累积暴露评估

目的分析云南省新鲜蔬菜中11种有机磷农药的残留情况,评估云南省居民有机磷农药的慢性累积暴露风险。方法对2012—2017年云南省新鲜蔬菜中11种有机磷农药含量数据进行统计分析,结合2012年中国居民营养与健康状况调查中新鲜蔬菜消费量数据,采用危害指数法评估云南省居民有机磷农药的慢性累积暴露风险。结果 2 150份样品中11种有机磷农药总检出率为14.1%(303/2 150),超标率为4.3%(93/2 150)。危害指数法评估结果显示云南省居民平均危害指数为0.382 5,城市男性和城市低收入人群危害指数较高,分别为0.526 7和0.489 0,但均小于1。氧化乐果的慢性累积暴露量贡献率最高(48.3%)。结论云南省新鲜蔬菜存在有机磷农药残留情况,云南省居民经新鲜蔬菜摄入的有机磷农药慢性累积暴露风险小,但仍存在违规使用和滥用农药的问题,需加强对农药生产使用的监管。     

Practical considerations on the use of predictive models for regulatory purposes

Interest in the use of quantitative structure-activity relationships (QSARs) for regulatory purposes has been growing steadily over the years, and many models have been evaluated under the guidance and acceptability criteria defined at the Setubal workshop held in March 2002. This work explores some of the practical issues related to the use of QSARs for regulatory purposes using results obtained from rat oral lethality and fish acute toxicity estimates generated from computational models (including TOPKAT, MCASE, OASIS, and ECOSAR). Using data submitted under the Environmental Protection Agency's (EPA's) High Production Volume (HPV) Challenge Program, the results on the quality of the estimations are compared using a standard statistical review and an additional classification approach in which the hazard predictions were grouped using well-defined regulatory criteria (those used in EPA's New Chemical Program). Our results indicate that an evaluation of a model's regulatory applicability and predictive power is ultimately dependent on the specific criteria used in the assessment process. This work also discusses the practical difficulties associated with defining the domain of a predictive model using the estimates of four different ready biodegradation models and experimental data submitted under the EPA's New Chemical program. Our results suggest that the method a model employs for its predictions is as important as the training set in determining its domain of applicability. Together, these results highlight the challenges associated with developing reliable and easily applied acceptability criteria for the regulatory use of QSAR models.     

山东省主产区苹果农药残留水平及累积急性 膳食摄入风险评估

目的评估目前山东主要苹果产区的农药残留水平,为农药残留监管提供科学依据。方法对采自山东苹果主产区的110个苹果样品运用现有的标准方法进行102种农药残留分析检测,利用急性参考剂量(acute reference dose,ARf D)和国家估计短期摄入量(international estimated short-term intake,IESTI)公式评估苹果农药累积急性风险。结果山东省苹果共检出26种农药残留,多残留(2种农残及以上)样品占样品总数的78%,所有样品检出农药残留量均未超过规定的最大残留限量值;检出苹果上禁用农药灭多威和未登记农药噻嗪酮、螺螨酯、杀铃脲;有机磷类、菊酯类、三唑类和烟碱类农药在山东苹果中累积急性膳食摄入风险(%ARf D值)分别为37.7%、7.37%、0.28%和1.53%。结论山东省苹果农药残留种类较多,残留水平不高,有机磷类、菊酯类、三唑类和烟碱类农药累计急性摄入风险较小,但需重点关注苹果上禁用农药和未登记农药。     

Considerations necessary in gathering occurrence data for selected unstable compounds in the USEPA Unregulated Contaminant Candidate List in USEPA Method 526

U.S. Environmental Protection Agency (EPA) Method 526 was developed for the analysis of target analytes that are subject to degradation by hydrolysis. Two technical hurdles that had to be overcome were preservation of the target analytes and selection of a suitable solid-phase extraction material. The target analytes were diazinon, disulfoton, fonofos, terbufos, prometon, 1,2-diphenylhydrazine, nitrobenzene, acetochlor, 2,4,6-trichlorophenol, 2,4-dichlorophenol, and cyanazine. Diazolidinyl urea was used for the first time as a microbial inhibitor in an EPA drinking water method. Experiment confirmed antimicrobial agents containing copper or mercury salts increased hydrolysis degradation rates. Trisodium ethylenediaminetetraacetic acid salt was added to chelate metal ions that may increase hydrolysis rates. A pH 7 buffer of tris(hydroxymethyl)aminomethane (Tris) and Tris hydrochloride was used to minimize rates of hydrolysis. The use of ascorbic acid prevented degradation of 2,4-dichlorophenol, terbufos, fonofos, diazinon, and disulfoton due to residual chlorine. Samples were extracted using a styrene divinylbenzene solid-phase material and analyzed by capillary column gas chromatography/mass spectrometry. A 21-day storage stability study, together with precision and accuracy studies, showed that this method has suitable sensitivity, accuracy, precision, and ruggedness for use in the EPA's Unregulated Contaminant Monitoring Rule drinking water occurrence survey.     

枸杞中拟除虫菊酯类农药残留水平及累积暴露评估

目的检测枸杞中的农药残留水平,并对拟除虫菊酯类农药的累积暴露风险进行评估,为是否需要制定枸杞中最大残留限量提供依据。方法收集40份不同来源不同产地的枸杞样品,对332种农药残留进行测定,其中包括15种拟除虫菊酯类农药。采用危害指数(HI)法对通过枸杞摄入拟除虫菊酯类农药产生的急性和慢性累积风险进行评估。结果通过方法学验证得出此方法适用于枸杞中拟除虫菊酯类农药的测定。结果显示4种拟除虫菊酯农药检出率均高于25%,分别为氯氰菊酯、氰戊菊酯、甲氰菊酯和氯氟氰菊酯。采用HI法进行累积暴露评估,得出拟除虫菊酯类农药的急性和慢性危害指数分别为0.497和0.016。结论枸杞在拟除虫菊酯类农药的累积摄入风险虽然较小,但由于其检出率较高,应持续保持对样品的监控,并考虑制定相应的最大残留限量值。     

吉林省种植基地蔬菜中农药污染特征及风险评价

目的 了解吉林省种植基地蔬菜中农药残留情况,并探明其污染风险状况。方法 在吉林省7个市县蔬菜主产区采集211份蔬菜样品,采用液相色谱串联质谱法和气相色谱串联质谱法测定其中80种农药残留水平,并分别用危害物风险系数法和食品安全指数法评价其风险状况。结果 结果表明,蔬菜样品中检出农药25种,以杀虫剂、低毒农药为主,检出率最高的为啶虫脒(5.21%),超标率最高的是氧乐果,农药残留超标的蔬菜为韭菜、芹菜、马铃薯和菜豆;从检出农药的风险系数看,氧乐果为高风险农药,毒死蜱和腐霉利为中风险农药,风险系数(R)分别为2.91、1.96和1.96;从食品安全指数评价结果看,吉林省蔬菜质量安全整体状况是可接受的,但克百威、氧乐果在蔬菜中残留的风险超过了可接受的限度,应该进入风险管理程序。结论 吉林省地产蔬菜中存在农药残留及超标情况,且存在农药多残留累积风险,建议相关部门加强对蔬菜生产者进行合理用药的培训,抓好产中的技术指导和产后的监管,保证蔬菜整体质量安全。