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.     

我国特殊医学用途配方食品蛋白质原料使用状况分析

目的 探讨分析蛋白质原料在特殊医学用途配方食品中的使用状况,为特殊医学用途配方食品研发中蛋白质原料的选择、产品的注册管理及临床使用提供参考。方法 结合特殊医学用途配方食品的注册审评情况,从法规标准、蛋白质原料特征及其在不同类型特殊医学用途配方食品中的使用等进行汇总分析。结果 蛋白质在特殊医学用途配方食品中具有重要的营养作用,常用的原料包括乳清蛋白、酪蛋白、大豆分离蛋白、水解蛋白及氨基酸等。基于不同的适用人群,蛋白质在全营养配方食品、蛋白质组件及特定全营养配方食品中具有相应的使用要求和临床应用特点。结论 基于目前的注册审评情况及文献查询情况,针对蛋白质原料和人体对蛋白质营养需求的相关研究较为成熟,但针对蛋白质原料在特殊医学用途配方食品中使用的研究仍较为有限。建议进一步加强蛋白质原料在特殊医学用途配方食品中使用的基础研究、标准法规的完善以及上市后产品临床使用情况的数据收集等工作。     

Recent developments in biochar as an effective tool for agricultural soil management: a review

In recent years biochar has been demonstrated to be a useful amendment to sequester carbon and reduce greenhouse gas emission from the soil to the atmosphere. Hence it can help to mitigate global environment change. Some studies have shown that biochar addition to agricultural soils increases crop production. The mechanisms involved are: increased soil aeration and water‐holding capacity, enhanced microbial activity and plant nutrient status in soil, and alteration of some important soil chemical properties. This review provides an in‐depth consideration of the production, characterization and agricultural use of different biochars. Biochar is a complex organic material and its characteristics vary with production conditions and the feedstock used. The agronomic benefits of biochar solely depend upon the use of particular types of biochar with proper field application rate under appropriate soil types and conditions. © 2016 Society of Chemical Industry     

土壤水分条件对白肋烟产、质量的影响及白肋烟灌溉的土壤水分指标研究

本项研究采用田间和盆栽试验相结合的方法研究了土壤水分条件对白肋烟产、质量和化学成分的影响.结果表明,白肋烟各生育期土壤相对含水量的适宜指标分别为移栽-团棵为70%、团棵-打顶为81%、打顶-采收为76%;干旱指标分别为移栽-团棵为58%、团棵-打顶为71%、打顶-采收为69%.白肋烟成熟阶段需水量相对较多,成熟期土壤相对含水量对白肋烟的成熟速度和化学成分的协调性及评吸质量的影响最为明显,在适宜的土壤相对含水量以下的范围内,表现出随土壤相对含水量升高,成熟速度加快,烟碱含量明显下降,内在化学成分更为协调和评吸质量提高.适宜的土壤相对含水量能明显提高白肋烟产量、产值和等级比重.     

Ecotoxicological effects of activated carbon amendments on macroinvertebrates in nonpolluted and polluted sediments

Amendment of contaminated sediment with activated carbon (AC) is a remediation technique that has demonstrated its ability to reduce aqueous concentrations of hydrophobic organic compounds. The application of AC, however, requires information on possible ecological effects, especially effects on benthic species. Here, we provide data on the effects of AC addition on locomotion, ventilation, sediment avoidance, mortality, and growth of two benthic species, Gammarus pulex and Asellus aquaticus , in clean versus polycyclic aromatic hydrocarbon (PAH) contaminated sediment. Exposure to PAH was quantified using 76 μm polyoxymethylene passive samplers. In clean sediment, AC amendment caused no behavioral effects on both species after 3-5 days exposure, no effect on the survival of A. aquaticus , moderate effect on the survival of G. pulex (LC(50) = 3.1% AC), and no effects on growth. In contrast, no survivors were detected in PAH contaminated sediment without AC. Addition of 1% AC, however, resulted in a substantial reduction of water exposure concentration and increased survival of G. pulex and A. aquaticus by 30 and 100% in 8 days and 5 and 50% after 28 days exposure, respectively. We conclude that AC addition leads to substantial improvement of habitat quality in contaminated sediments and outweighs ecological side effects.     

Measurement of helium isotopes in soil gas as an indicator of tritium groundwater contamination

The focus of this study was to define the shape and extent of tritium groundwater contamination emanating from a legacy burial ground and to identify vadose zone sources of tritium using helium isotopes (3He and 4He) in soil gas. Helium isotopes were measured in soil-gas samples collected from 70 sampling points around the perimeter and downgradient of a burial ground that contains buried radioactive solid waste. The soil-gas samples were analyzed for helium isotopes using rare gas mass spectrometry. 3He/4He ratios, reported as normalized to the air ratio (RA), were used to locate the tritium groundwater plume emanating from the burial ground. The 3He (excess) suggested that the general location of the tritium source is within the burial ground. This study clearly demonstrated the efficacy of the 3He method for application to similar sites elsewhere within the DOE weapons complex.     

Uptake by perennial ryegrass of iodide, elemental iodine and iodate added to soil as influenced by various amendments.

Perennial ryegrass was grown in pots in a sandy loam soil, into which iodide, elemental iodine or iodate had been incorporated at a rate of 20 mg I/kg. The uptake of iodine into the herbage was much greater from iodate than from the other two forms. Replacement of 5 % of the soil by well-decomposed farmyard manure reduced uptake from all three forms of iodine more than ten-fold. Similar replacement by chalk reduced uptake from iodide but increased uptake from iodate. The recovery of added iodine in three successive harvests of ryegrass ranged from 0.03% for elemental iodine in combination with soil + FYM to 2.16% for iodate in combination with soil + chalk.     

The use of vermicompost in organic farming: overview,effects on soil and economics

Vermicomposting is a process in which earthworms are used to convert organic materials into humus‐like material known as vermicompost. A number of researchers throughout the world have found that the nutrient profile in vermicompost is generally higher than traditional compost. In fact, vermicompost can enhance soil fertility physically, chemically and biologically. Physically, vermicompost‐treated soil has better aeration, porosity, bulk density and water retention. Chemical properties such as pH, electrical conductivity and organic matter content are also improved for better crop yield. Nevertheless, enhanced plant growth could not be satisfactorily explained by improvements in the nutrient content of the soil, which means that other plant growth‐influencing materials are available in vermicomposts. Although vermicomposts have been shown to improve plant growth significantly, the application of vermicomposts at high concentrations could impede growth due to the high concentrations of soluble salts available in vermicomposts. Therefore, vermicomposts should be applied at moderate concentrations in order to obtain maximum plant yield. This review paper discusses in detail the effects of vermicompost on soil fertility physically, chemically and biologically. Future prospects and economy on the use of organic fertilizers in the agricultural sector are also examined. © 2014 Society of Chemical Industry     

Accounting for soil biotic effects on soil health and crop productivity in the design of crop rotations

There is an urgent need for novel agronomic improvements capable of boosting crop yields while alleviating environmental impacts. One such approach is the use of optimized crop rotations. However, a set of measurements that can serve as guiding principles for the design of crop rotations is lacking. Crop rotations take advantage of niche complementarity, enabling the optimization of nutrient use and the reduction of pests and specialist pathogen loads. However, despite the recognized importance of plant–soil microbial interactions and feedbacks for crop yield and soil health, this is ignored in the selection and management of crops for rotation systems. We review the literature and propose criteria for the design of crop rotations focusing on the roles of soil biota and feedback on crop productivity and soil health. We consider that identifying specific key organisms or consortia capable of influencing plant productivity is more important as a predictor of soil health and crop productivity than assessing the overall soil microbial diversity per se. As such, we propose that setting up soil feedback studies and applying genetic sequencing tools towards the development of soil biotic community databases has a strong potential to enable the establishment of improved soil health indicators for optimized crop rotations. © 2014 Society of Chemical Industry     

不同干燥方式对大豆浓缩蛋白溶解度和结构影响

采用不同干燥方式,分别对一次醇洗、二次醇洗大豆浓缩蛋白进行脱溶处理,考察不同脱溶条件,着重对大豆浓缩蛋白在水中、6M尿素溶液及1%SDS溶液中溶解度进行测定;并通过对游离巯基测定及DSC对蛋白热稳定性研究,探讨SPC溶解度与其结构之间关系。     

典型农业区域土壤有机污染状况监测研究

采用GC,HPLC和GC-MS等方法对河南省6种典型农业区域土壤有机污染状况进行监测研究,结果表明:以六六六和滴滴涕为主的有机氯农药浓度总体远低于GB15618-1995二级限值.污染水平总体上处于安全状态;多环芳烃普遍检出,检出率为100%.含量均值在50.6×10-7%～96.4×10-7%之间,远低于欧洲土壤质量标准,但苯并(a)芘的检出率为46%～100%,含量均值在1.24×10-7%～4.97×10-7%之间,已超出俄罗斯土壤质量标准,有潜在危害性.污水灌溉区土壤中的多环芳烃总量和苯并(a)芘平均含量在6种区域中为最高,显示污水灌溉是土壤中多环芳烃污染的主要原因.     

New device and method for flux-proportional sampling of mobile solutes in soil and groundwater

The importance of monitoring the transport of organic contaminants in soil and groundwater, and the pros and cons of existing sampling methods, are outlined. A new, alternative sampling method is proposed, using a passive sampler that functions as a water-permeable, semi-infinite sink for passing solutes of interest. Tracers integrated in the device store information on the volume of water passing through the sampler during the installation period. The conceptual basis of the sampling method is described. This device enables flux-proportional monitoring of the concentrations of mobile contaminants in the soil and groundwater. 14C-labeled phenanthrene (PHEN) and glyphosate (GLY) are used as case study compounds in laboratory experiments. The sorption capacities and uptake kinetics of 13 adsorbents are screened and compared, as well as the dissolution kinetics of three tracer salts: calcium citrate, calcium fluoride (CaF2), and calcium hydrogen phosphate (CaHPO4). The application of the passive sampler is then demonstrated in long-term laboratory experiments, using large soil columns under steady-state hydraulic conditions. The accumulated flux of PHEN was sampled with an accuracy of 3.6%-17.8%, using graphitized carbon, hexagonal mesoporous silica, and cross-linked polymers as adsorbents. The accumulated flux of GLY was sampled with an accuracy of 12.4%, using gamma-alumina as an adsorbent. The advantages and limitations of this new environmental monitoring method are discussed.     

The effects of organic and conventional nutrient amendments on strawberry cultivation: Fruit yield and quality

BACKGROUND: The nutrition of food is increasingly important to consumers. The popularity of organic food rests partly on the assumption that these products are healthier despite a lack of conclusive evidence. The effects of organic and inorganic fertilizer amendments on parameters of strawberry fruit quality, in terms of sugar, macro‐ and micro‐nutrients concentrations, and total antioxidant capacity were compared. RESULTS: Treatments did not affect sugar content or total antioxidant capacity. Inorganic fertilizer treatments increased S and Mn content of berries compared to organic treatments. The K and P content of berries differed among years. CONCLUSIONS: Organic amendments did not increase the fruit quality of strawberries compared to inorganic amendments. Copyright © 2008 Society of Chemical Industry     

农业生态措施对改善土壤性状及烟叶品质效应研究初报

对施用秸秆、饼肥、微生物肥等农业生态措施改善土壤性状及烟叶品质的效应进行了研究。结果表明,在土壤中施用3750kg/hm^2腐熟秸秆,配以复合肥和豆饼,可改善土壤物理性状,提高土壤有机质含量,并可改善烟叶质量,尤其对提高香气质、香气量效果较好;施用7500kg/hm^2腐熟秸秆,配以复合肥,虽然对改善土壤理化性状效果较好,但对烟叶品质有负面影响;在土壤中施用微生物肥料对改善烟叶质量,提高香气质、香气量效果较好,但由于施用微生物肥后,加速了土壤有机质的耗损,使土壤环境恶化,对持续发展不利;单独施用等氮量腐熟饼肥,对改善土壤环境及烟叶品质的效果均不及施3750kg/hm^2腐熟秸秆的处理。     

喷雾干燥条件对豆粉速溶性的影响

以喷雾干燥豆粉的流动性、分散性和溶解性为指标对豆乳浆料喷雾干燥时的浆料条件及喷雾干燥器型号进行了优化。结果表明,浆料热处理前添加还原剂有利于改善喷雾干燥豆粉的溶解性,增大浆料固形物浓度有助于改善喷雾干燥粉的流动性和堆积密度,但却会使干燥豆粉的溶解性下降,适宜的浆料固形物含量为15%;离心喷雾设备蒸发量的增大有助于改善豆粉的流动性和分散性,而压力喷雾干燥样品的分散性和堆积密度均优于离心喷雾样品。扫描电镜(SEM)图片显示,与采用离心式雾化器所得样品相比,采用压力式雾化器得到的豆粉颗粒大而均匀,且颗粒表面呈多孔状,样品速溶性好。      

Assessment of chemical mixtures and groundwater effects on Daphnia magna transcriptomics

Small organisms can be used as biomonitoring tools to assess chemicals in the environment. Chemical stressors are especially hard to assess and monitor when present as complex mixtures. Here, fifteen polymerase chain reaction assays targeting Daphnia magna genes were calibrated to responses elicited in D. magna exposed for 24 h to five different doses each of the munitions constituents 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, trinitrobenzene, dinitrobenzene, or 1,3,5-trinitro-1,3,5-triazacyclohexane. A piecewise-linear model for log-fold expression changes in gene assays was used to predict response to munitions mixtures and contaminated groundwater under the assumption that chemical effects were additive. The correlations of model predictions with actual expression changes ranged from 0.12 to 0.78 with an average of 0.5. To better understand possible mixture effects, gene expression changes from all treatments were compared using high-density microarrays. Whereas mixtures and groundwater exposures had genes and gene functions in common with single chemical exposures, unique functions were also affected, which was consistent with the nonadditivity of chemical effects in these mixtures. These results suggest that, while gene behavior in response to chemical exposure can be partially predicted based on chemical exposure, estimation of the composition of mixtures from chemical responses is difficult without further understanding of gene behavior in mixtures. Future work will need to examine additive and nonadditive mixture effects using a much greater range of different chemical classes in order to clarify the behavior and predictability of complex mixtures.     

土壤中铬含量对农产品安全性影响评价

目的 探索土壤中铬含量对农产品质量安全的影响.方法 采集农产品生产基地土壤样品120个, 同步采集成熟农产品样品200个, 测定土壤样品pH、全量铬和农产品样品总铬含量, 协同分析土壤铬污染情况和农产品铬含量情况.结果 土壤铬含量风险筛选范围占 9.17%, 存在轻微铬污染.农产品中铬含量合格率达100%, 安全性高....     

Assessment of the suitability of soil amendments to reduce 137Cs and 90Sr root uptake in meadows

In situ remediation strategies are an alternative approach in the management of radioactive contaminated areas, especially when based on modification of soil properties by the addition of amendments. Here, this strategy is applied to reduce 137Cs and 90Sr soil-plant transfer in meadows from areas of Russia, Belarus, and Ukraine affected by the Chernobyl fallout. Meadows were established on podzolic and peaty soils. Amendments covered a wide range of materials, such as loamy and sandy soils, polygorskite clay, phosphorite, turf, and sapropel. Field experiments showed the poor efficiency of most of the materials: only the polygorskite clay provoked a notable reduction (1.5-2-fold) in 137Cs root uptake. Subsequent laboratory characterization showed the lack of significant changes in the radiocesium interception potential and soil solution composition in the amended soils, a fact that helped to explain the lack of effect on the reduction of transfer. Moreover, a laboratory methodology based on the quantification of the adsorption potential of the amendments and the reversibility of the adsorption process was applied. This methodology was first proposed for the correct selection of the suitable materials to be used to decrease radionuclide root uptake in future remediation actions and then validated with data of the previous field experiments.