苯胺环境标准样品研制中紫外分光光度法的应用

研究了苯胺弱酸性水溶液的紫外吸收特性,并将研究结果运用于苯胺水质标准样品的研制。用紫外分光光度法对标准样品进行均匀性、稳定性和定值测定,从而简化了分析手续,取得了良好的分析结果     

Feasibility of On-line Measurement of Sewage Components Using the UV Absorbance and the Neural Network

The objective of this study was to test the feasibility of a new method to improve the accuracy in the estimation of sewage components. Adding to the regression of sewage components with UV (ultraviolet) absorbance values, a proposed method considered an unclear but existing relationship among characteristic of sewage production. Sewage production showed very defined profiles due to the daily human activities. So the main idea was the combination of measuring the UV absorbance values and analyzing the characteristics of the sewage production. For this purpose, 446 sewage samples taken at every 2-h interval for 51 days at a wastewater treatment plant were statistically analyzed using neural network (NN). NN was trained with 350 data sets (about 29 days) of UV absorbance values, flow rate and time. And as a result, it could predict 96 data (12 days) as a validation, indicating that estimation accuracies were improved to higher level than those of the linear regressions. The proposed method could estimate concentrations of total nitrogen (TN) and total phosphate (TP) within practical accuracies as well as total suspended solid.     

紫外分光光度法在水中阴离子表面活性剂标准样品研制中的应用

研究了阴离子表面活性剂水溶液的紫外吸收特性,并将研究结果用于阴离子表面活性剂水质标样的稳定性,均匀性和定值工作,简化了操作手续,获得了准确的分析结果。     

UV Spectroscopic Monitoring of Vaporized Monoaromatic Hydrocarbons from Petroleum-Contaminated Soils

Fast and simple systems using ultraviolet (UV) absorbance were examined for on-line monitoring of monoaromatic hydrocarbons from petroleum-contaminated soils in this research. Since soil particles hinder the UV light transmittance, the absorbance measurement of vaporized monoaromatic hydrocarbons in soil gas extracted from petroleum-contaminated soils was proposed. In the fixed system that exhibited higher sensitivity than the portable one, the absorbance intensity of benzene, toluene, ethylbenzene, and xylene increased in proportion to the concentration of the contaminants. The portable system, however, was suitable for screening purpose, while it exhibited faster response. There was no interference from water, which helps the applicability of the proposed systems to the actual fields.     

Fluoride Content in Drinking Water Supplies of Riyadh, Saudi Arabia

Groundwater supplies about 34% ofthe total water demand for the capital city of SaudiArabia, Riyadh. The other 66% is desalinatedseawater. The fluoride level in Riyadh drinking watersupplies was evaluated. Samples were collected fromselected wells, treatment plants, desalinatedseawater, distribution network and 19 locally producedand imported bottled water. The fluoride level in theinfluent to the seven groundwater treatment plants andtheir final product water were in the range of 0.63–1.6 and 0.23–1.1 mg/L, respectively. Blending of theplants product water with the desalinated seawaterresulted in the fluoride level ranging from 0.01–0.5 mg/Lin the distribution network. Ninety percent of thesamples collected from the distribution network hadfluoride levels less than or equal to the calculatedweighted average value of 0.24 mg/L. The locallyproduced bottled waters as compared to 8 imported oneshave shown fluoride levels in the range of 0.2–0.83and 0.04–0.2 mg/L, respectively. In general, thefluoride level in Riyadh drinking water supplies isbelow the optimum recommended level of 0.7 to1.2 mg/L. It is therefore recommended thatfluoridation be considered in water treatment plants.     

紫外光度法测定地表水中石油类的油标选择

精选了一种新油标。采用这种油标,可使紫外分光光度法测地表水中石油类的令人满意,省工省时。     

紫外分光光度法与亚甲兰分光光度法测定水中硫化物方法的对比及评价

对测定水和废水中溶解性硫化物的亚甲兰分光光度法及紫外分光光度法进行了对比性研究,并通过实际标准样品的测定,对2种测定方法在测定下限、线性范围和灵敏度及准确性等方面进行了评述,并提出了相关建议。     

Effect of vehicle exhaust on the quantity of polycyclic aromatic hydrocarbons (PAHs) in soil

PAHs are formed during the incomplete combustion of organic substances containing carbon and hydrogen and are one of the first atmospheric pollutants identified as carcinogens. Most of the PAH environmental burden is found in the soil (95%). Soil samples collected from different roadsides were analyzed for seven polycyclic aromatic hydrocarbons (PAHs). The quantitative and qualitative analysis was carried out by UV Spectrophotometer. The individual PAH value ranged from 0.1 to 18.0 mg/kg. Phenenthrene and Pyrene were found to be the most abundant compounds. Vehicle emissions are the principal source of PAH in the Roadside soils. The highest concentration was found at site S2 (Hasthtnagri Roadside) which shows the highest traffic density.     

The impact of ozone depletion on skin cancer incidence: An assessment of the Netherlands and Australia

Evidence indicates that the concentration of stratospheric ozone has already decreased globally over the past several years and additional decreases are to be expected over the coming decades. A further depletion of the ozone layer would lead to an increase in the amount of ultraviolet (UV) radiation. One of the adverse effects of particularly UV-B radiation on human health would be an increase in the incidence of skin cancer. In this study an integrated model is presented to assist in assessing the changes in skin cancer incidences in relation to changes in the amount of stratospheric ozone, for the Netherlands and Australia. Although surrounded by large uncertainties, model results show that, in view of the several delay mechanisms and, additionally, the ageing of the population, future increases in skin cancer incidence cannot be reversed.     

紫外分光光度法测定水和废水中硫化物

对紫外分光光度法测定水和废话中硫化物的方法进行了研究,试验了稳定时间、干扰物质、碱溶液浓度对测定的影响,提出了最佳测定条件。该方法检测限为０．０４ｍｇ／Ｌ,相对标准偏为１．４％,加标回收率在９１．６％～１０１．９％之间。     

The Contribution of Acadia PRIMENet Research to Science and Resource Management in the National Park Service

Acadia National Park was one of the 14 sites included in the Park Research and Intensive Monitoring of Ecosystems network (PRIMENet). For eight years the EPA monitored ultraviolet (UV) radiation at this site, with the National Park Service (NPS) sponsoring a total climate and air monitoring station. Under the auspices of PRIMENet, research projects were initiated that investigated the effects of UV on amphibians, determined watershed mass balances, and developed a model of deposition along an elevational gradient. The monitoring data and research results have been used by park management to protect vegetation and water resources from ozone and deposition. These data are now being used to develop a “vital signs” monitoring program under the NPS’ Inventory and Monitoring Program. These data sets have been used in regional, national and international programs to protect human health and resources from air pollution. Public outreach has been accomplished through web site resources and via the Schoodic Education and Research Center.     

UV/H2O2 oxidation of arsenic and terbuthylazine in drinking water

Arsenic is a widespread contaminant in the environment. The intake of water containing high concentrations of arsenic could have serious impact on human health, such as skin and lung cancer. In the European Union, thus, also in Italy, the arsenic limit in drinking water is 10 μg L^?1. Several water remediation treatment technologies are available for arsenic removal. For some processes, the removal efficiencies can be improved after an oxidation step. Most full-scale applications are based on conventional oxidation processes for chemical micropollutant removal. However, if water contains arsenic and refractory organic contaminants, the advanced oxidation processes could be considered. The aim of this work was to investigate the effectiveness of ultraviolet (UV) radiation alone and in combination with hydrogen peroxide for the oxidation of arsenic and terbuthylazine (TBA). The experimental tests were performed in groundwater at the laboratory scale (0.1 mg L^?1 As(III) and 10 μg L^?1 TBA). Hydrogen peroxide alone (15 mg L^?1) was ineffective on both arsenic and TBA oxidation; the 253.7-nm radiation alone did not oxidize arsenic(III), but photolyzed efficiently TBA (52 % removal yield at a UV dose of 1,200 mJ cm^?2). The UV/H₂O₂ advanced oxidation (UV dose 600–2,000 mJ cm^?2, 5–15 mg L^?1 H₂O₂) was the most effective process for the oxidation of both arsenic and TBA, with observed oxidation efficiencies of 85 and 94 %, respectively, with 5 mg L^?1 H₂O₂ and a UV dose of 2,000 mJ cm^?2.     

Measurement of chemical oxygen demand (COD) in natural water samples by flow injection ozonation chemiluminescence (FI-CL) technique

COD determination based on ozone oxidation of alpha-naphthol combined with UV radiation (UV-O3) has been studied in the present work. Utilizing the phenomenon that luminol can be oxidized by the dissolved ozone to produce luminescence, we have established a new method of utilizing aqueous chemiluminescence to determine COD. The kinetics and mechanism of the ozonation reaction of alpha-naphthol have been investigated in order to gain a better understanding of the general applicability and limitation of the technique. Real world samples were analyzed and the results show that the relative error of COD(FI-CL) measurement for water samples was < 10%. Compared with the results of the conventional potassium permanganate method, the COD values of the FI-CL method are consistently higher (0-20% relative). The higher COD values suggest that the ozone-UV system is a more effective oxidation technique.     

BOD5 Estimation by Using UV Absorption and COD for Rapid Industrial Effluent Monitoring

The study dealt with the method to predict the BOD₅ in effluent from industrial wastewater by using the UV absorption from two wavelengths, 260 and 550 nm. The interference from suspended solids was reduced. In the same time, COD was used as the secure value to calculate BOD₅. From the representative wastewater treatment plants, the estimated effluent BOD₅ of wastewater from the Para rubber industry showed an average error at ±2.97 mg/l. While it was at ±3.31 mg/l, for frozen seafood industry. The simple mathematic equations in this study gave the assuring method for BOD₅ estimation without time consuming.     

Quality assessment of various bottled waters marketed in Saudi Arabia

This study focuses on the chemical analysis of the available brands of domestic bottled water in Riyadh City, Saudi Arabia. The distribution of the chemical constituents (major, minor, and trace elements) is determined and compared with the chemical content labeled on the bottles and with drinking water standards of Saudi Arabian, World Health Organization, and U.S. Environmental Protection Agency. The obtained results indicated that except for fluoride and bromate, the concentrations of dissolved salts, soluble cations and anions, nitrate, and trace elements of most bottled waters on sale were within the permissible limits set by standards used. On the other hand, the comparison between determined and reported label values recorded a substantial variation in some parameter values. Results indicated that more than 18 % of the sampled bottled waters exceeded the allowable limits for drinking water. Generated Piper diagrams revealed that the majority of investigated waters were sodium chloride–sulfate type; however, the hydrochemical modeling indicated that all water samples were undersaturated for anhydrite, gypsum, and halite.     

NITRATE CONCENTRATIONS IN RIYADH, SAUDI ARABIA DRINKING WATER SUPPLIES

Riyadh, Saudi Arabia is supplied with drinking water fromboth desalinated sea water and treated groundwater sources. Sampleswere analysed for NO₃ from selected deep and shallow wells, two locations within the city's six groundwater treatment plants, thedesalinated sea water and distribution network. Average nitrateconcentrations (as NO₃) were 8.2 and 15.8 mg/L for deep andshallow well waters, respectively. The average nitrate concentrations (asNO₃) in the groundwater treatment plants influent waters and thefinal product water were 16.2 and 8.5 mg/L, respectively. Due toblending of the plants' product water with the desalinated sea water, theaverage network nitrate concentration was 4.4 mg/L. The scheduledwater interruption does not seem to cause any appreciable change in thenitrate levels in the distribution network.     

Quality of wastewater reuse in agricultural irrigation and its impact on public health

This study is planned to perform a sanitary survey of the largest sewage treatment plant in Riyadh, KSA, fortnightly for 6 months to examine its effluent quality as an example for the growing dependence on reuse of treated municipal wastewater in agricultural irrigation purposes to cope with increasing water shortage. The biological and physico-chemical parameters of 12 wastewater samples from the plant were examined using standard methods. The physico-chemical analysis indicated that the surveyed municipal wastewater treatment plant contained some of the studied parameters, such as turbidity, total suspended solids, biochemical oxygen demand, chemical oxygen demand and residual chlorine above the maximum permissible wastewater limits set by the Saudi Standards. However, heavy metal concentrations in all samples were lower than the recommended standards. Total and faecal coliform counts were above the permissible limits indicating poor sanitation level. Fifty percent of all wastewater samples were contaminated with faecal coliforms but, surprisingly, Escherichia coli were only detected in 8.3 % of the samples. Regular monitoring and enhancement of microbial and physico-chemical parameters of the wastewater quality served by different wastewater treatment plants for reuse in agricultural irrigation is recommended to preserve the environment and public health.     

Appearance of aldehydes in the surface layer of lake waters

The paper presents results concerning the changes in the content of aldehydes in samples of lake water collected near the lake surface. The study of lake waters was undertaken to explain which physicochemical parameters of the environment have the greatest influence on the level of aldehydes, which of the aldehydes are most often met in surface water and in what concentrations. We observed that formaldehyde, acetaldehyde, propanal, glyoxal, methylglyoxal and acetone were commonly present in surface water samples, while semi-volatile and poorly soluble aldehydes such as nonanal and decanal were observed seasonally. The contents of total aldehydes varied in a wide range, from 55 to 670 μg/l, and the concentration of total organic carbon varied significantly from 3 to 18 mg /l, but there was no evident correlation between them in all of samples. The total content of aldehydes did not depend on the meteorological parameters such as air temperature, UV radiation and ozone concentration; however, it was noted that the level of carbonyl concentration is related to the period of intense precipitation: in the period of very low precipitations, the highest contents of total aldehydes were determined in all of the water samples, and in the periods of intense precipitations, the content of total aldehydes was drastically smaller.     

Evaluation of the NIOSH draft method 5525 for determination of the total reactive isocyanate group (TRIG) for aliphatic isocyanates in autobody repair shops. National Institute for Occupational Safety and Health

This paper evaluates the performance of the NIOSH draft method 5525 for analysis of monomeric and TRIG aliphatic isocyanates in autobody repair shops. It was found that an optimized pH gradient enhanced noticeably the resolution and, therefore, identification of aliphatic isocyanates. Samples proved to be very stable for at least a year when stored at -13 degrees C in the freezer, and no major stability problems were found for the MAP reagent. The detector response factor RSD for selected MAP ureas was 40% in the fluorescence (FLD), 3% in the UV at 254 nm (UV254), and 1% in the UV at 370 nm (UV370). The mean FLD/UV254 and UV254/UV370 detector response ratios of standards were 31.7 (RSD = 37.8) and 17.1 (RSD = 5.4), respectively. The FLD/UV254 ratio in bulks varied from 0.41 to 1.97 times the HDI monomer ratio. The mean UV254/UV370 ratio in bulks was 16.1 (range 14.1 to 19.2, N = 38). Mean (range) recovery of 92 (91.2-93.2)% was found for the N3300 (isocyanurate) spiked on 25 mm quartz fiber filters in the range 0.07 to 2.2 microg NCO ml(-1). Mean (range) recovery for impingers was 100.7 (91.7-106.0)% for N3300 in the concentration range of 0.018 to 2.5 microg NCO ml(-1) and 81.0 (76.1-89.1)% for IPDI in the concentration range of 0.016 to 1.87 microg NCO ml(-1). Analytical method precision was 3.4% and mean bias 7.4% (range = 0-25%). The NIOSH draft method 5525 provides flexibility, enhanced sensitivity and specificity, powerful resolution, and very small compound-to-compound variability in the UV254, resulting in a more reliable identification and quantification of aliphatic isocyanates.     

Heavy metals in cooler waters in Riyadh, Saudi Arabia

Water samples were collected from 400 coolers in Riyadh area. From each cooler, one feed and one cooled water samples were collected. These samples were analyzed for trace metals like Al, Cr, Cu, Fe, Mn, Ni, Pb, and Zn by Inductively Coupled Plasma (ICP) Spectrophotometer equipped with ultrasonic nebulizer. Out of 400 coolers, water from 382 (95.50%) were found to meet World Health Organization (WHO), Saudi Arabian Standards Organization (SASO), and United States Environmental Protection Agency (USEPA) drinking water standards whereas water from 18 coolers (4.50%) were found to have elevated levels of Fe, Pb, and Ni metals. In one cooler, water was allowed to stand for 12 h and a 1 L sample collected every 2 h. All the metals mentioned above with the exception of Pb were found to increase due to standing time.