An approach to developing numeric water quality criteria for coastal waters using the SeaWiFS Satellite Data Record

Human activities on land increase nutrient loads to coastal waters, which can increase phytoplankton production and biomass and associated ecological impacts. Numeric nutrient water quality standards are needed to protect coastal waters from eutrophication impacts. The Environmental Protection Agency determined that numeric nutrient criteria were necessary to protect designated uses of Florida's waters. The objective of this study was to evaluate a reference condition approach for developing numeric water quality criteria for coastal waters, using data from Florida. Florida's coastal waters have not been monitored comprehensively via field sampling to support numeric criteria development. However, satellite remote sensing had the potential to provide adequate data. Spatial and temporal measures of SeaWiFS OC4 chlorophyll-a (Chl(RS)-a, mg m(-3)) were resolved across Florida's coastal waters between 1997 and 2010 and compared with in situ measurements. Statistical distributions of Chl(RS)-a were evaluated to determine a quantitative reference baseline. A binomial approach was implemented to consider how new data could be assessed against the criteria. The proposed satellite remote sensing approach to derive numeric criteria may be generally applicable to other coastal waters.     

MTBE ambient water quality criteria development: a public/private partnership

A public/private partnership was established in 1997, under the administrative oversight of the American Petroleum Institute (API), to develop aquatic toxicity data sufficient to calculate ambient water quality criteria for methyl tertiary-butyl ether (MTBE), a gasoline oxygenate. The MTBE Water Quality Criteria Work Group consisted of representatives from private companies, trade associations, and USEPA. Funding was provided by the private entities, while aquatic biological/toxicological expertise was provided by industry and USEPA scientists. This public/private partnership constituted a nonadversarial, cost-effective, and efficient process for generating the toxicity data necessary for deriving freshwater and marine ambient water quality criteria. Existing aquatic toxicity data were evaluated for acceptability, consistent with USEPA guidance, and nineteen freshwater and marine tests were conducted by commercial laboratories as part of this effort to satisfy the federal criteria database requirements. Definitive test data were developed and reported under the oversight of industry study monitors and Good Laboratory Practice standards auditors, and with USEPA scientists participating in advisory and critical review roles. Calculated, preliminary freshwater criteria for acute (Criterion Maximum Concentration) and chronic (Criterion Continuous Concentration) exposure effect protection are 151 and 51 mg MTBE/L, respectively. Calculated, preliminary marine criteria for acute and chronic exposure effect protection are 53 and 18 mg MTBE/L, respectively. These criteria values may be used for surface water quality management purposes, and they indicate that ambient MTBE concentrations documented in U. S. surface waters to date do not constitute a risk to aquatic organisms.     

Evaluation of the quality of protein mixtures based on collagen and blood. Comparison of biological and chemical evaluation criteria in rats

The quality of protein mixtures on the basis of blood protein, collagen, wool and other proteins was tested using different chemical and biological criteria of protein evaluation. Before mixing the single proteins were hydrolysed enzymatically by means of acid or alkaline proteinases. In this study the influence of both hydrolysis processes on the bioavailability of the protein mixtures was also considered. The N-balance experiments were carried out with weanling Sprague-Dawley rats in groups of n = 6 animals each. The estimated BV's showed that the protein quality was significantly affected by both hydrolysis procedures especially when the hydrolysates were compared with the non-hydrolysed protein components. The BV's also showed that the quality of all mixtures of protein hydrolysates was less than that of casein (reference protein) and the availability of the alkaline hydrolysed proteins better than that with acid proteinase treated proteins. This result could be confirmed by the calculated chemical criteria E/T- and E/N-ratios, EAA-Index and Arnould-Index. The results of the growth-criteria PER, NPR and RNV did neither correspond with each other nor they were of good agreement with N-balance based BV and NPU.     

Coffee mixtures—Spectrophotometric method for the determination of coffee content

The method described in this paper gives results which are good approximations of the actual coffee contents of roasted coffee/roasted chicory and roasted coffee/roasted fig mixtures.It has also been applied to coffee and chicory essence, cereal products and instant coffee/chicory, instant coffee/cereal/chicory mixtures.     

水质高锰酸盐指数测定中误差来源与控制分析

影响高锰酸盐指数检测结果精确度的因素很多,应严格依照相关规范标准开展水质高锰酸盐指数测定工作,在配制KMnO4溶液、收集与保存水样、加热处理、检测条件、校准系数K值等方面加强控制.本研究分析水质高锰酸盐指数测定中误差来源与控制,为完善操作流程,减少或消除误差提供参考.     

地表水水质自动监测系统的应用效果观察

随着社会经济的飞速发展和科技水平的日益提高,我国地表水水质检测工作也取得了显著成效.鉴于此,本文从水质自动检测系统的应用现状入手,分析当前地表水水质自动监测系统应用中存在的主要问题及对策,为广大同仁们提供有益的借鉴和思考.     

响应面法分析保水剂对蛋糕品质的影响

在单因素试验的基础上,以感官评分为指标,通过响应面分析法研究山梨糖醇、甘油、丙二醇对蛋糕品质的影响。结果表明:在山梨糖醇3%、甘油1%、丙二醇0.5%的条件下,蛋糕的感官评分最高为92,水分活度降低了0.029,贮存时间延长了12 d。     

Calculation of water sorption isotherms for multicomponent protein-containing mixtures

This paper presents a method of calculating water sorption isotherms for multicomponent mixtures from the mass fractions and sorption isotherms of the particular components. Interactions between the components are also considered. to compare experimental and calculated data, investigations on protein concentrates produced from blood plasma, baker's yeast and whey were carried out. Calcium carbonate, molecular sieves, cellulose, wheat bran and some types of flour were used as additives.     

Screening criteria for long-range transport potential of organic substances in water

Screening of long-range transport potential (LRTP) of organic chemicals in water requires the development of criteria in analogy to the existing LRTP criteria for airborne chemicals. According to the Stockholm Convention, compounds mainly partitioning into air are assumed to be prone to LRTP if they have a half-life in air of more than two days. Using mean flow velocities of European rivers (0.7-1 m/s) and of ocean currents running into the Arctic Ocean (0.28-0.9 m/s), we derived corresponding half-life criteria for freshwater and seawater (10 days and 90 days, respectively). Next, we calculated the characteristic travel distance (CTD) of several thousand chemicals from the Canadian Domestic Substances List (DSL) and all current POPs using the multimedia model ELPOS. This shows that the CTD in water dominates the CTD in air only for chemicals that are characterized by a large half-life in water and a low air-water partition coefficient (about 38% of the nonionic organic substances selected from the DSL). In particular, there are substances that are not classified as persistent compounds in water but exhibit higher CTDs for transport in water than for transport in air. Finally, we evaluated whether the LRTP boundary derived from POP reference chemicals has to be revised if LRTP in water is included and found that this boundary can be applied to all organic chemicals regardless of their transport in air or water.     

Liquid chromatography mass spectrometry for plant sterol oxide determination in complex mixtures

Plant sterol oxidation products were determined by a sensitive liquid chromatography (LC) method with atmospheric pressure chemical ionization mass spectrometry (APCI-MS). Fragmentation of oxides was studied with stepwise fragmentation (full scan, MS², MS³) with ion trap tandem mass spectrometry. The applicability of the method was investigated using thermo-oxidized (180 °C) sterol mixture containing sitosterol, campesterol, stigmasterol and brassicasterol as a model sample. With this method, all major oxidation products of sitosterol, campesterol, stigmasterol and brassicasterol could be detected in the same run without derivatization. This LC-MS method proved to be a powerful alternative to gas chromatographic (GC) methods for the analysis of plant sterol oxides in complex mixtures and is a promising tool for future oxidation mechanism studies.     

Development of a method for water determination in lactose

The determination of water content of lactose and the water activity, which is related to it, are important to assess its microbiological stability as well as its technical and commercial quality. Lactose is a very important product in the dairy sector, but also in the pharmaceutical domain.     

Microwave dielectric spectroscopy for the determination of pork meat quality

The use of dielectric spectra to detect quality defects in porcine muscle during postmortem period was evaluated. The changes in dielectric spectra during meat ageing were also studied. For these purposes, dielectric spectra were measured by using an Agilent 85070E Open-ended Coaxial Probe connected to an Agilent E8362B Vector Network Analyzer from 500 MHz to 20 GHz parallel and perpendicular to muscle fiber direction. This study reveals that dielectric properties at two punctual frequencies (0.5 GHz and 10 GHz) are a useful tool to determine meat quality classes (RFN, PSE, and DFD) soon (6 h) after slaughter. Based on these results, it is possible to develop control algorithms in order to discriminate low quality pork meats and to decide their best uses. Moreover, the evolution of dielectric spectra during meat ageing showed important variations only in DFD meats, while in PSE and RFN meats the variations were observed only at some punctual frequencies of the spectrum during the 24 h after slaughter.     

响应曲面法研究热处理对鲜切荸荠品质的影响

以荸荠为原料,采取中心复合旋转实验设计,研究不同的热处理温度、热处理时间以及贮藏时间对鲜切荸荠冷藏过程中品质的影响。利用SAS9.0软件,通过响应曲面法建立热处理对鲜切荸荠脆性、失重率和抗坏血酸含量的二次多项数学模型,对其显著性、拟合程度等进行分析;同时利用模型的响应面对影响鲜切荸荠品质的关键因子及其相互作用进行了探讨。结果表明,影响鲜切荸荠脆性和抗坏血酸含量的关键因素是热处理温度和贮藏时间,影响鲜切荸荠失重率的关键因素是贮藏时间,热处理时间及其他交互作用对鲜切荸荠的这些品质影响不显著。     

Structural and dynamical properties of water in sugar mixtures

Trehalose, a bioprotective sugar, has very important applications in different industrial fields, such as food, pharmaceutical and cosmetic industry. Trehalose can be used as a new multi-functional ingredient with considerable potential for the industry. The characterization of molecular mechanisms underlying the manifold functions of trehalose is very important for the understanding and exploitation of the potentialities of the disaccharide.     

Ultrasonic velocity measurements in ethanol–water and methanol–water mixtures

In this study, ultrasonic velocity measurements were used to estimate the alcohol type and volume concentration in water–alcohol binary mixtures. Varying mixtures of ethanol in water and methanol in water were prepared and the ultrasonic velocities for each concentration level were measured between 10 and 50 °C. Results of the statistical analyses indicated that ultrasonic velocity measurements can be used to distinguish between ethanol and methanol in a water–alcohol binary mixture and to estimate the alcohol concentration level. The results were validated by testing three commercial liquids with a known ethanol concentrations and one commercial liquid with known methanol concentration.