VOCs,pesticides, nitrate,and their mixtures in groundwater used for drinking water in the United States

Samples of untreated groundwater from 1255 domestic drinking-water wells and 242 public supply wells were analyzed as part of the National Water-Quality Assessment Program of the U.S. Geological Survey between 1992 and 1999. Wells were sampled to define the regional quality of the groundwater resource and, thus, were distributed geographically across large aquifers, primarily in rural areas. For each sample, as many as 60 volatile organic compounds (VOCs), 83 pesticides, and nitrate were analyzed. On the basis of previous studies, nitrate concentrations as nitrogen > or = 3 mg/L were considered to have an anthropogenic origin. VOCs were detected more frequently (44%) than pesticides (38%) or anthropogenic nitrate (28%). Seventy percent of the samples contained at least one VOC, pesticide, or anthropogenic nitrate; 47% contained at least two compounds; and 33% contained at least three compounds. The combined concentrations of VOCs and pesticides ranged from about 0.001 to 100 microg/L, with a median of 0.02 microg/L. Water from about 12% of the wells contained one or more compounds that exceeded U.S. Environmental Protection Agency drinking-water standards or human health criteria, primarily because of nitrate concentrations exceeding the maximum contaminant level in domestic wells. A mixture is defined as a unique combination of two or more particular compounds, regardless of the presence of other compounds that may occur in the same sample. There were 100 mixtures (significantly associated with agricultural land use) that had a detection frequency between 2% and 19%. There were 302 mixtures (significantly associated with urban land use) that had a detection frequency between 1% and <2%. Only 14 compounds (seven VOCs, six pesticides, and nitrate) contributed over 95% of the detections in these 402 mixtures; however, most samples with these mixtures also contain a variety of other compounds.     

Medical costs of smoking in the United States: estimates, their validity, and their implications

OBJECTIVE: To compare estimates of the medical costs of smoking in the United States and to consider their relevance to assessing the costs of smoking in developing countries and the net economic burden of smoking. DATA SOURCES: A Medline search through early 1999 using keywords "smoking" and "cost", with review of article reference lists. STUDY SELECTION: Peer-reviewed papers examining medical costs in a single year, covering the non-institutionalised American population. DATA EXTRACTION: Methods underlying study estimates were identified, described, and compared with attributable expenditure methodology in the literature dealing with costs of illness. Differences in methods were associated with implied differences in findings. DATA SYNTHESIS: With one exception, the studies find the annual medical costs of smoking to constitute approximately 6-8% of American personal health expenditures. The exception, a recent study, found much larger attributable expenditures. The lower estimates may reflect the limitation of analysis to costs associated with the principal smoking-related diseases. The higher estimate derives from analysis of smoking-attributable differences in all medical costs. However, the finding from the most recent study, also considering all medical costs, fell in the 6-8% range. CONCLUSIONS: The medical costs of smoking in the United States equal, and may well exceed, the commonly referenced figure of 6-8%. This literature has direct methodological relevance to developing countries interested in assessing the magnitude of their current cost-of-smoking burden and their future burdens, with differences in tobacco use histories and the availability of chronic disease treatment affecting country-specific estimates. The debate over the use of gross or net medical cost estimates is likely to intensify with the proliferation of lawsuits against the tobacco industry to recover expenditures on tobacco-produced disease.     

TRLFS evidence for precipitation of uranyl phosphate on the surface of alumina: environmental implications

We studied the ligand-enhanced sorption of uranyl ions (1-12 μM) on α-alumina colloids suspended in (and pre-equilibrated with) solutions at various concentrations of phosphate ions (P(T) = 0-900 μM). A highly sensitive technique, time resolved laser-induced fluorescence spectroscopy (TRLFS), was used to examine the chemical speciation of uranyl sorbed at trace concentrations (0.4-4 μmol U·g?1). The suspensions with P(T) ≥ 100 μM exhibited high uranyl adsorption, and a very high intensity of fluorescence that increased with the sorbed amounts of phosphate and uranyl. These samples exhibited similar spectral and temporal characteristics of fluorescence emission, evidencing a uniform speciation pattern and a single coordination environment for sorbed U, despite large variation in parameters such as aqueous uranyl speciation, U loading, and extent of coverage of alumina by secondary Al phosphates precipitating on the surface. The results pointed formation of surface precipitates of uranyl phosphates, which are characterized by high quantum yield, peak maxima at positions similar to those of U(VI) phosphate minerals and four lifetimes indicating distortions, in-homogeneities or varying number of water molecules in the lattice. The findings have major implications for our understanding of the mechanisms of immobilization of U at trace levels on surfaces of oxides submitted to phosphated solutions in soils with low pH.     

Microbiological water quality requirements for salad irrigation in the United Kingdom

The growth in United Kingdom salad production is dependent on irrigation to maintain product quality. There are concerns that irrigation with poor-quality water could pose a disease risk. This article examines the key issues in the emerging debate on the microbiological quality of water used for salad irrigation in the United Kingdom. The links between irrigation water quality and foodborne disease, and the current international guidance on irrigation water quality, are firstly reviewed. The findings indicate that a number of recent food-poisoning outbreaks have been linked to the consumption of fresh fruits and vegetables and that unhygienic product handling is implicated as the principal source of contamination. There is also credible evidence that salads contaminated in the field, including by irrigation water, can pose a small disease risk at the point of sale. Although irrigation water-quality standards exist in various forms internationally, there is no nationally agreed on standard used in the United Kingdom. This paper then describes the results of a survey conducted in 2003 of United Kingdom irrigation practices that might influence the microbiological quality of salads. The survey showed that surface water is the principal irrigation water source, that overhead irrigation predominates, that the gap between the last irrigation and harvest may be < 24 h in many cases, and that current water-quality monitoring practices are generally very limited in scope. This paper concludes with a discussion of the issues emerging from the review and survey, including the need for improved water-quality monitoring, and the problems associated with establishing water-quality standards that could be either too strict or too lax.     

Nationwide evaluation of quality and composition of colostrum on dairy farms in the United States

The objective of this study was to characterize the quality of maternal colostrum (MC) fed to newborn dairy calves in the United States and identify the proportion of MC that meets industry standards for IgG concentration and total plate count (TPC). Samples of MC (n=827) were collected from 67 farms in 12 states between June and October 2010. Samples were collected from Holsteins (n=494), Jerseys (n=87), crossbred (n=7), and unidentified dairy cattle (n=239) from first (n=49), second (n=174), third or greater (n=128), and unknown (n=476) lactations. Samples were identified as fresh (n=196), refrigerated (n=152), or frozen (n=479) before collection, as well as whether the sample was from an individual cow (n=734) or pooled (n=93). Concentration of IgG in MC ranged from <1 to 200mg/mL, with a mean IgG concentration of 68.8 mg/mL (SD=32.8). Almost 30% of MC contained <50 mg of IgG/mL. The IgG concentration increased with parity (42.4, 68.6, and 95.9 mg/mL in first, second, and third and later lactations, respectively). No differences in IgG concentration were observed among breeds or storage method; however, IgG was highest in samples collected in the Midwest and lowest in samples collected in the Southwest (79.7 vs. 64.3 mg/mL). Total plate count of samples ranged from 3.0 to 6.8 log(10) cfu/mL, with a mean of 4.9 log(10) cfu/mL (SD=0.9) and was greater in samples collected in the Southeast compared with other regions of the country. Pooled samples had greater TPC than individual samples and refrigerated samples had greater TPC than frozen and fresh samples. Almost 43% of samples collected had TPC >100,000 cfu/mL, 16.9% of the samples had >1 million cfu/mL. Only 39.4% of the samples collected met industry recommendations for both IgG concentration and TPC. Almost 60% of MC on dairy farms is inadequate, and a large number of calves are at risk of failure of passive transfer or bacterial infections, or both. Also, the data indicate that regional differences exist in colostrum quality.     

Including mixtures in the determination of water quality criteria for herbicides in surface water

Monitoring programs throughout America and Europe have demonstrated the common occurrence of herbicides in surface water. Nevertheless, mixtures are rarely taken into account in water quality regulation. Taking mixtures into account is only feasible if the water quality criteria (WQC) of the single compounds are derived by a common and consistent methodology, which overcomes differences in data quality without settling on the lowest common denominator but making best use of all available data. In this paper, we present a method of defining a risk quotient for mixtures of herbicides with a similar mode of action (RQm). Consistent and comparable WQC are defined for single herbicides as a basis for the calculation of the RQm. Derived from the concentration addition model, the RQm can be expressed as the sum of the ratios of the measured environmental concentration and the WQC for each herbicide. The RQm should be less than one to ensure an acceptable risk to aquatic life. This approach has the advantage of being easy to calculate and communicate, and is proposed as a replacement for the current limit of 0.1 microg/L for herbicides in Switzerland. We illustrate the proposed approach on the example of five commonly applied herbicides (atrazine, simazine, terbuthylazine, isoproturon, and diuron). Their risk profile, i.e., the RQm as a function of time for one exemplary river, clearly shows that the single compounds rarely exceeded their individual WQC. However, the contribution of peaks of different seasonally applied herbicides, whose application periods partially overlap, together with the continuously emitted herbicides from nonagricultural use, results in the exceedance of the RQm threshold value of one upon several occasions.     

Tracking toxaphene in the North American Great Lakes basin. 1. Impact of toxaphene residues in United States soils

A coupled atmospheric transport model was employed to study six scenarios to assess the contribution of reemission and long-range transport of toxaphene from different sources in the United States to its environmental fate in the Great Lakes ecosystem in the year 2000. Modeled air concentrations at the first model level (1.5 m) range from less than 5 pg m(-3) over the upper Great lakes (Lakes Superior and Huron) to several tens of picograms per cubic meter over the lower Great Lakes (Lakes Erie and Ontario) in the summer but drop off to the range from 0.05 to 2 pg m(-3) in the wintertime. The modeled toxaphene depositions to the lakes suggest a decreasing trend from the mid-1990s to 2000. Modeling results showed that, on an annual basis, for the Great Lakes basin as a whole, the southeast U.S. sources made the largest contribution to the toxaphene air concentrations and dry and wet depositions at 72%, 78%, and 88% respectively. The model results also showed that a significant proportion of these contributions occur during relatively short episodic events due primarily to the interseasonal changes in atmospheric circulation patterns.     

高温酸沉对大豆分离蛋白品质的影响

为了拓宽大豆分离蛋白的应用范围，降低大豆分离蛋白中大豆异黄酮的含量，考察了高温酸沉对大豆分离蛋白品质的影响。分析了不同酸沉温度下，大豆分离蛋白中主要大豆异黄酮类物质含量的变化，大豆乳清中粗蛋白质含量及固形物含量的变化，大豆分离蛋白水合蓝光白度的变化，以及大豆分离蛋白凝胶值的变化。结果表明：酸沉温度从70 ℃升高到85 ℃，大豆异黄酮总量降低了43.84%，其中大豆苷、染料木苷含量分别降低了88.76%、83.95%，黄豆黄苷降到了检出限以下，而大豆苷元、染料木素含量分别提高了72.51%和143.47%，黄豆黄素的含量变化不显著；随酸沉温度升高，大豆乳清中的粗蛋白质含量和固形物含量不断降低，与酸沉温度70 ℃时相比，酸沉温度85 ℃时粗蛋白质含量降低了25.12%，固形物含量降低了6.34%；随酸沉温度升高，大豆分离蛋白的水合蓝光白度不断增加且增速不断提高，与酸沉温度70 ℃时相比，酸沉温度85 ℃时水合蓝光白度增加了26.83%；随酸沉温度升高，大豆分离蛋白的凝胶值不断降低，与酸沉温度70 ℃时相比，酸沉温度85 ℃时凝胶值降低了57.02%。综上，高温酸沉可有效控制大豆分离蛋白中大豆异黄酮的含量，提高大豆分离蛋白的水合蓝光白度和回收率，对开发低异黄酮含量的婴幼儿产品有积极意义。     

Characterizing dependence of pesticide load in surface water on precipitation and pesticide use for the Sacramento River watershed

Transport of pesticides by surface runoff during rainfall events is a major process contributing to pesticide contamination in rivers. This study presents an empirical regression model that relates pesticide loading over time in the Sacramento River with the precipitation and pesticide use in the Sacramento River watershed. The model closely simulated loading dynamics of diazinon, simazine, and diuron during 1991-1994 and 1997-2000 winter storm seasons. The coefficients of determination for regression ranged from 0.168 to 0.907, all were significant at <0.001. The results of this study provide strong evidence that precipitation and pesticide use are the two major environmental variables dictating the dynamics of pesticide transport into surface water in a watershed. The capability of the statistical model to provide time-series estimates on pesticide loading in rivers is unique and may be useful fortotal maximum daily load (TMDL) assessments.     

美国强化食品的安全管理及对我国的启示

目的全面分析美国近年来强化食品的发展情况,并借鉴其安全管理的成功经验措施,以期完善我国强化食品安全管理现状,促进强化食品市场健康良好地运行。方法通过研究美国近年来强化食品的发展状况,围绕政府、企业、消费者、生产技术等几个方面,分析其如何从政策、法律法规、标准的完善提高消费者接受水平,应用科学技术采取具体的措施,借鉴美国成功的经验来改善当前国内的管理现状。结果分析了美国强化食品安全管理措施,并分析了中国强化食品安全管理存在的问题和不足,给中国强化食品安全管理提供了操作性更强的建议。结论本研究对美国强化食品的现状及安全管理进行了系统地分析,并借鉴了其中有效的管理方法和经验,为今后中国强化食品安全管理的发展方向提供了有益的思路。     

Hexabromocyclododecanes in indoor dust from Canada, the United Kingdom, and the United States

alpha-, beta-, and gamma-hexabromocyclododecane diastereomers (HBCDs) were measured in house dust from Birmingham, U.K. (n=31, median concentration=730 ng sigmaHBCDs g(-1)); Amarillo/Austin, TX (n=13, 390 ng g(-1)); and Toronto, Canada (n=8, 640 ng g(-1)). Concentrations in dust (n=6, 650 ng g(-1)) from U.K. offices were within the range for UK homes. Concentrations from each country were statistically indistinguishable. In one UK house dust sample, 110,000 ng g(-1) was recorded-the highest recorded in indoor dust to date. While upper bound average U.K. dietary exposures for adults and toddlers, respectively, are 413 and 240 ng sigmaHBCDs day(-1), U.K. adults and toddlers daily ingesting, respectively, 50 and 200 mg of dust contaminated at the 95th percentile concentration are exposed, respectively, to 1100 and 4400 ng sigmaHBCDs day(-1). Normalized to body weight, this high-end exposure scenario estimate for toddlers is within the range reported elsewhere for occupationally exposed adults. While in commercial formulations gamma-HBCD predominates (>80%), alpha-HBCD in dust constitutes 14-67% of sigmaHBCDs (average 32%). Hence the predominance of the alpha-diastereomer in humans may arise partly from dust ingestion, and not solely to in vivo metabolism (when alpha-HBCD is formed from bioisomerization of other diastereomers), or dietary exposure (where alpha-HBCD predominates in most foodstuffs).     

美国智慧食品安全监管方法及启示

2019年4月,美国食品和药物管理局提出"智慧食品安全新时代"这一倡议,旨在继续实施美国《食品安全现代化法案》(FDA Food Safety Modernization Act, FSMA)科学和基于风险的要求,同时纳入新技术、工具和方法,帮助消费者更好地免受食源性疾病侵害。智慧食品安全作为一种新的食品安全方法,促进社会和商业部门使用新技术,如区块链、传感器技术、物联网和人工智能,以建立一个更数字化、可追溯和更安全的食品体系,包括依靠技术的可追溯性和对食源性疾病暴发的响应、更智能的预防工具和方法、适应新商业模式和零售现代化、食品安全文化4个方面。本文介绍了美国智慧食品安全监管方法,并通过借鉴美国今后食品安全监管思路,提出对未来我国食品安全监管的建议。     

Flux rates of atmospheric lead pollution within soils of a small catchment in northern Sweden and their implications for future stream water quality

It is not well-known how the accumulated pool of atmospheric lead pollution in the boreal forest soil will affect the groundwater and surface water chemistry in the future as this lead migrates through the soil profile. This study uses stable lead isotopes (206Pb/207Pb and 208Pb/ 207Pb ratios) to trace the transport of atmospheric lead pollution within the soil of a small catchment and predict future lead level changes in a stream draining the catchment. Low 206Pb/207Pb and 208Pb/207Pb ratios for the lead in the soil water (1.16 +/- 0.02; 2.43 +/- 0.03) and streamwater (1.18 +/- 0.03; 2.42 +/- 0.03) in comparison to that of the mineral soil (>1.4; >2.5) suggest that atmospheric pollution contributes by about 90% (65-100%) to the lead pool found in these matrixes. Calculated transport rates of atmospheric lead along a soil transect indicate that the mean residence time of lead in organic and mineral soil layers is at a centennial to millennial time scale. A maximum release of the present pool of lead pollution in the soil to the stream is predicted to occur within 200-800 years. Even though the uncertainty of the prediction is large, it emphasizes the magnitude of the time lag between the accumulation of atmospheric lead pollution in soils and the subsequent response in streamwater quality.     

Dietary exposures for the safety assessment of seven emulsifiers commonly added to foods in the United States and implications for safety

ABSTRACT

Dietary exposure assessment using food-consumption data and ingredient-use level is essential for assessing the safety of food ingredients. Dietary exposure estimates are compared with safe intake levels, such as the acceptable daily intake (ADI). The ADI is estimated by applying a safety factor to an experimentally determined no-observed-adverse-effect level of a test substance. Two food ingredients classified as emulsifiers, carboxymethylcellulose (CMC) and polysorbate 80 (P80), received attention recently due to their putative adverse effects on gut microbiota. Because no published dietary exposure estimates for commonly used emulsifiers exist for the US population, the current investigation focused on the estimation of dietary exposure to seven emulsifiers: CMC, P80, lecithin, mono- and diglycerides (MDGs), stearoyl lactylates, sucrose esters, and polyglycerol polyricinoleate. Using maximum-use levels obtained from publicly available sources, dietary exposures to these emulsifiers were estimated for the US population (aged 2 years and older) for two time periods (1999–2002 and 2003–10) using 1- and 2-day food-consumption data from the National Health and Nutrition Examination Survey, and 10–14-day food-consumption data from NPD Group, Inc.’s National Eating Trends – Nutrient Intake Database. Our analyses indicated that among the emulsifiers assessed, lecithin and MDGs have the highest mean exposures at about 60 and about 80 mg kg^–1 bw day^–1, respectively, whereas the exposure to CMC is half to one-third that of lecithin or MDGs; and the exposure to P80 is approximately half that of CMC. The review of available safety information such as ADIs established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), in light of our updated dietary exposure estimates for these seven emulsifiers, did not raise safety concerns at the current specified levels of use. Additionally, by examining two time periods (1999–2002, 2003–10), it was concluded that there is no evidence that exposure levels to emulsifiers have substantially increased.     

中美大麦品质检验标准的比较研究

目的大麦成为中国近年来进口量和进口额最大的谷物品种,其中美国大麦是中国进口大麦非常重要的品种之一。了解中美大麦品质检验标准差异意义重大。方法本文对我国大麦品质标准与美国品质标准进行了对比分析,总结了我国现有标准的概况,重点对我国大麦品质标准现状存在的问题进行了探讨。结果与结论我国大麦品质标准体系发展趋势应根据我国大麦品质标准体系的现状以及大麦产业发展对标准体系的需求,借鉴国外的先进经验。本文提出了今后我国大麦品质标准体系建设的发展方向,以标准引导和促进大麦产业的健康发展,为全面提升我国大麦产业提供有力保障。     

英美加三国食品监管法规及监督检查现状

近年来,食品安全事件频发,食品安全问题开始受到人们越来越多的重视,成为了公众关注的焦点。纵观世界范围,各国政府都在保障本国食品安全方面做着巨大努力。本文以英国、美国和加拿大等发达国家为例,对其食品监管法律法规及监督检查情况进行梳理和总结,分析了英、美、加3国食品安全监管模式以及值得借鉴的经验与成果,结合我国食品安全监管实际情况提出了意见与建议,为我国下一步食品安全相关法律法规的制修订及食品安全监管工作的开展提供参考。