标准分析方法测定废水中苯胺类的不足与改进

标准分析方法测定苯胺类时,废水中某些物质在酸化条件下,要与过量的氨基磺酸铵和盐酸萘乙二胺进行显色反应,引起正干扰。正确的方法是分析水样的同时,分取与显色反应相同体积废水样,只进行加氨基磺酸铵和盐酸萘乙二胺的操作步骤,测定其吸光度。由水样的吸光度减去后者吸光度的差值来计算苯胺类浓度是科学、准确的。     

Degradation of three fungicides following application on strawberry and a risk assessment of their toxicity under greenhouse conditions

The health risk to humans of pesticide application on minor crops, such as strawberry, requires quantification. Here, the dissipation and residual levels of three fungicides (pyraclostrobin, myclobutanil, and difenoconazole) were studied for strawberry under greenhouse conditions using high-performance liquid chromatography (HPLC)-tandem mass spectrometry after Quick, Easy, Cheap, Effective, Rugged, and Safe extraction. This method was validated using blank samples, with all mean recoveries of these three fungicides exceeding 80 %. The residues of all three fungicides dissipated following first-order kinetics. The half-lives of pyraclostrobin, myclobutanil, and difenoconazole were 1.69, 3.30, and 3.65 days following one time application and 1.73, 5.78, and 6.30 days following two times applications, respectively. Fungicide residue was determined by comparing the estimated daily intake of the three fungicides against the acceptable daily intake. The results indicate that the potential health risk of the three fungicides was not significant in strawberry when following good agricultural practices (GAP) under greenhouse conditions.     

Transient modeling of trickling filters for biological ammonia removal

A dynamic model for nitrifying trickling filters is developed, based on material balances in the biofilm and the bulk liquid. The model predicts the profile of ammonia as a function of the operating parameters (volumetric flow rate and feed ammonia concentration) and the biofilm thickness as a function of filter depth and time. This revised version was published online in July 2006 with corrections to the Cover Date.     

Copper availability assessment of Cu-contaminated vineyard soils using black oat cultivation and chemical extractants

Grapevines grown on acid soils with low fertility in southern Brazil are treated with intense foliar applications of copper (Cu) fungicides, resulting in an increased level of Cu in the soil and increased toxicity. The present study evaluated the accumulation and bioavailability of Cu, and soils with varying levels of Cu from the main producing regions of southern Brazil were collected. The forms of Cu present in the soil were assessed using chemical extractants; additionally, oat cultivation was performed, reflecting the use of the plant as an indicator of Cu bioavailability. Cu accumulated in the topsoil, mainly in bioavailable forms, and there was also an increase of Cu up to a depth of 0.4 m. Cu was primarily found in the mineral fraction, with apparent saturation of the soil organic matter functional groups. Inceptisol and Alfisol soils with a long history of cupric fungicide application were found to have levels of Cu toxic to oat plants. Furthermore, accumulated copper in Alfisol soil from the Campanha Gaúcha region of the state of Rio Grande do Sul had higher bioavailability compared to Cu accumulated in Inceptisol soil from the Serra Gaúcha region. In addition, the copper concentration in roots was found to serve as an indicator of Cu bioavailability in soil, but not of copper phytotoxicity in plants.     

Photodegradation of Pyrimethanil induced by iron(III) in aqueous solutions

In this study an abiotic process was suggested to evaluate the behaviour of Pyrimethanil (antibotrytic fungicide) in real matrices. This process consists of a photodegradation of the fungicide carried out in the presence of iron(III) in three types of buffer; acetate, phosphate and citrate. The experimental results show that the nature of buffered solutions influences both the rate of disappearance of Pyrimethanil and, in the case of citrate, also the kind of by-products formed during the photodegradation process. For each case examined, the breakdown products were identified by using liquid chromatography (LC) or gas chromatography (GC), coupled with mass spectrometry (MS). The degradation pathways of the fungicide were proposed and the relative kinetic constants were evaluated. The abiotic photodegradation process shows the possibility of different pathways for Pyrimethanil degradation in environmental matrices such as the soil, plants and foodstuffs, where iron (free and/or bonded) is a natural component.     

Accumulation of ammonia and other potentially noxious gases on live export shipments from Australia to the Middle East

Noxious gases on ships are irritant pollutants that have potential impacts on the comfort and health of both livestock and humans. Identification of environmental influences on the pollutants will assist live exporters to control them. Ammonia, hydrogen sulphide and carbon dioxide, as well as wet and dry bulb temperature, dew point, air speed and depth of faeces that the sheep stood in, were measured on two ship voyages in which sheep were transported from Australia to the Middle East. Daily measurements were made at 20 measurement locations over 12 days. At four sites, the mean ammonia concentration for the voyage was above the recommended maximum limit for the live export industry (25 ppm). The mean ammonia concentrations at the remaining 16 sites were below 18 ppm and considered safe. High ammonia concentrations were localised and occurred particularly on closed decks, as well as at the front of the vessel and near the engine block on open decks. Ammonia concentration on the open decks was correlated with cumulative wind during the voyage, air speed, dew point, wet bulb temperature and faecal pad depth, and on the closed decks with dew point, and wet and dry bulb temperature. Hydrogen sulphide (<1.8 ppm) and carbon dioxide (<1900 ppm) concentrations were low and did not pose a risk to animal or human welfare or health. The results suggest that high ammonia concentrations occur in those parts of the ship where there is insufficient ventilation and/or high temperatures and humidity.     

Comparison of linuron degradation in the presence of pesticide mixtures in soil under laboratory conditions

It is widely recognised that complex interactions occur between chemicals in mixtures. In many agricultural situations, the use of tank mixes and complex spray programs is a common practice. Insecticides, fungicides and a herbicide being applied in potato protection were used in this research. Interactions between linuron and insecticides, such as thiamethoxam or clothianidin, and fungicides, such as mancozeb or chlorothalonil, were examined in soil. The degradation rate of linuron in soil during laboratory incubation in six treatments was studied. Mixtures of linuron with mancozeb in sandy loam and clay loam soils had a significant effect on the persistence of this herbicide. For example, for the same herbicide, t _1/2 values for linuron were from 37 days in sandy loam to 44 days in clay loam. These values changed (64–67 days) when thiamethoxam and mancozeb were in soil. When mancozeb was added only, the half-life values were from 59 to 62 days, respectively. Other mixtures with chlorothalonil, thiamethoxam and clothianidin did not have any effect. In order to compare linuron degradation rates in soils, a single first-order model and expanded statistical analysis were used.     

Assessing the Effects of Atmospheric Ethylene on Epinasty and Tuber Yield of Potato (Solanum Tuberosum L.) Near Polyethylene Manufacturing Plants

A multi-year programme was performed to assess the effects of atmospheric ethylene on potato (Solanum tuberosum L.) in the vicinity of polyethylene manufacturing plants. There was a strong temporal variation of the hourly ethylene concentrations measured close to the sources from 1982 through 1991. Growing seasonal means exceeded 12 g m^–3 ethylene, the threshold for phytotoxic effects under laboratory conditions. Young test plants of potato showed an epinastic response to enhanced levels of ethylene. This response was reversible and did not occur when atmospheric ethylene was not detected. Based on hourly observations for the growing seasons of 1984 through 1991, epinasty occurred on average during circa 5% of the growing season and varied from circa 1% in 1985 to circa 18% in 1991. At night, ethylene concentrations were higher and epinasty was more frequent than during daylight hours. The intermittent exposures to ethylene did not affect tuber yield for the growing seasons of 1982 through 1990. The occurrence of epinasty indicated that ethylene exposure levels in the vicinity of the industrial sources might be sufficiently high to affect sensitive plants.     

Land Cover Changes as a Result of Environmental Restrictions on Nitrate Leaching in Dairy Farming

Nitrate leaching forms an important environmental problem because it causes pollution of groundwater and surface water, and adds to already problematic eutrophication. This study analyses the impact of reductions in nitrate leaching on land cover decisions of dairy farms, of which the activities make an important contribution to nitrate leaching. As the level of nitrate leaching depends on groundwater depth as well as on the supply of nitrogen, spatial variation in groundwater levels will cause a spatial variation in land cover under restrictions on nitrate leaching. A non-linear partial optimisation model for the economic and ecological aspects of the problem were used to show how land cover and dairy farms' financial balances change when nitrate losses are reduced. The model is spatially explicit, and describes nitrate leakage and yields of maize and grass as a function of groundwater depth, including the effects of various grazing systems. The model analyses the decisions of a risk neutral agent who minimises costs under the following constraints: (i) production, feed requirements and mass balances for fodder; (ii) constraints for nitrate leaching. Economic costs are attributed to increased costs of fodder and processing of manure when nitrate restrictions are tightened. An important result of the study is the variation in compliance costs and land cover for maize and grass production brought about by spatial variation in groundwater depth. While the effects are negligible for some shallow groundwater classes, it is extremely difficult in other classes – if not impossible – to obtain the EU standard of maximum admissible losses of 34 kg N ha^–1 at low costs. The study shows an important reduction in land cover by maize.     

Secondary desertification due to salinization of intensively irrigated lands: The Israeli experience

Secondary salinization of intensively irrigated lands is an increasingly alarming redesertification process experienced in many irrigated regions of the developed countries. The major cause is a profound interference in the geochemical/salt balances of irrigated regions. A case-in-point is the recent salinization of the Yizre'el Valley, a 20,000 ha intensively irrigated region in Israel. The extremely intensive and advanced agroecosystem developed in the region since the 1940s included pumping and importing irrigation water by the National Water Carrier, large-scale reclamation and reuse of municipal sewage water, winter flood impoundment in reservoirs for summer irrigation, and cloud seeding to enhance rainfall. Modern irrigation methods were applied, including sprinkler, trickle, moving-line, and center-pivot systems. Water use efficiency at any level was very high. Nevertheless, large-scale salinization of regional water resources and many fields had developed in the mid-1980s. Reconstructing and evaluating the water and salt balances of the Yizre'el Valley (using Cl as the representative salt constituent) shows that as water use in the valley increased to about 60 million m³ per year, the importing of soluble salts by water totaled 15,000 tons of Cl per year. Recirculated salt — salt picked up by impounded surface water and applied to fields — increased significantly and in the late 1980s amounted to more than 9,000 tons Cl per year. The source of recirculated salts was the accumulated salts in soils and in the shallow aquifer in the valley, which were leached by floodwater or drained or infiltrated into reservoirs, grossly and adversely affecting water quality. Analysis of the Yizre'el Valley's case points to the utmost importance of maintaining the geochemical balances in addition to increasing irrigation efficiency. An irrigated region may achieve geochemical balance by the following means: limiting the extent of irrigated areas, developing a well-maintained drainage system that drains tail-water and salinized shallow-aquifer water, and devoting a significant portion of water for regional leaching. The sustained long-term productivity of irrigated lands in arid zones crucially depends on correctly managing water and soil resources. Regional management of irrigated lands to prevent secondary desertification will be aimed at carefully balancing the undisputed benefits of irrigation with the long-term (on time scales of 10 to 100 years) detrimental processes set in motion when irrigation is introduced to arid and semiarid zone soils.     

Catalytic hydrodechlorination of 1,2-dichloroethane using copper nanoparticles under reduction conditions of sodium borohydride

1,2-Dichloroethane (1,2-DCA) is a raw material used for the manufacture of vinyl chloride monomer (VCM) and therefore has very often been detected in the groundwater nearby the VCM manufacturing plant. Zero-valent iron (ZVI) is capable of degrading a wide array of highly chlorinated contaminants; however, the reactivity of ZVI towards 1,2-DCA is very low. In this study, zero-valent copper nanoparticles have been synthesized for effective dechlorination of 1,2-DCA under reduction conditions of sodium borohydride. Copper nanoparticles consisted of mainly metallic copper (Cu(0)) with small amounts of cuprous oxide (Cu(2)O). They have surface areas of about 19.0 m(2) g(-1) and an average diameter of 15 nm. Batch experiments were conducted to test the effectiveness of copper nanoparticles for 1,2-DCA degradation using sodium borohydride as electron donors where the ORP was measured as -1100 mV. More than 80% of 1,2-DCA (30 mg L(-1)) was rapidly degraded within 2 h in the presence of both copper nanoparticles (2.5 g L(-1)) and borohydride (25 mM). No reduction of 1,2-DCA was observed when the system contained either copper nanoparticles alone or borohydride alone. The degradation intermediates included ethane and ethylene accounting for 79% and ～1.5% of the 1,2-DCA lost, respectively. Potential environmental applications can be achieved by immobilizing copper nanoparticles onto the surface of reducing metals to form a reactive bimetallic structure.     

湿法脱硫后高湿烟气中SO3酸雾监测方法研究

利用三氧化硫(SO3)发生装置以及模拟烟气湿法脱硫系统,研究了烟气再热温度、恒温水浴温度、采样速率、冷凝管类型规格及吸收瓶个数等不同采样参数对SO3酸雾采集率的影响。结果表明,当烟气再热温度低于烟气酸露点时会导致SO3酸雾收集率下降,采用控制冷凝法采样时应使用大流量(10L/min)采样,冷凝管应选择外套长度为400 mm的蛇形螺旋冷凝管,并将冷凝管置于温度为65℃左右的恒温水浴中;用碱液吸收法采样时应串联3个吸收瓶后,使用小流量(1L/min)采样。烟气温湿度、二氧化硫(SO2)浓度以及烟气中共存组分等对碱性吸收法的采集影响较大,而对控制冷凝法几乎没有影响。因此确立了针对湿法脱硫后高湿烟气环境下SO3酸雾的监测方法为控制冷凝法更为适宜。     

A Screening Test for the Determination of Ethylene Sensitivity

Ethephon, which releases ethylene within plant tissues after application, was chosen to perform assessments of the relative sensitivity of crops to ethylene and to determine which stages of plant development were most sensitive. The species chosen were: barley, wheat, oats, canola and field pea, all of which are important crops in the province of Alberta, Canada. Plants were treated with ethephon at one of 7 different stages. Plants were assessed for their vegetative and reproductive growth, including height, biomass, yield and seed quality. Visual symptoms were photographed and documented to compare them with symptoms caused by ethylene applied as a gas. It was concluded that in barley, wheat and canola the late vegetative and early reproductive stages were most sensitive, at least when sensitivity was defined as reductions in yield and quality. As for field pea, ethephon had no effect on yield but did cause increased numbers of pods, which in certain conditions could lead to increased yields. Significant effects on vegetative growth were only observed in the early vegetative stages of development but with no effects on yield. The screening protocol successfully identified sensitive cultivars and growth stages for further investigation of the effects of ethylene exposure.     

Regional evaluation of mass element fluxes: Geomon network of small catchments

Monitoring of element flows and their mass balances in the natural unit of the biosphere represented by a small catchment appears to be the most suitable for the solution of complex problems such as the deterioration of environmental quality. Long-term collection of comparable biogeochemical data, which will enable the identification of environmental trends, is the main aim of the GEOMON network. One of the most important applications of these data will be the calculation of critical loads. The Czech Geological Survey possesses data from 44 catchments in the former Czechoslovakia. Qualitative and quantitative data on inputs in atmospheric deposition and outputs via surface runoff are available. Simple input-output mass balances yield estimates of total accumulation or loss of individual components. Some examples of interpretations of the GEOMON data, especially in connection with different bedrock types, will be given.     

New thiol adsorbent grafted on silica gel: synthesis,characterization and employment for heavy metal adsorptions

Silica gel surface has been modified in two reaction steps: (i) the silylating agent 3-mercaptopropyltrimetoxysilane was firstly immobilized to give a surface Sil-SH and (ii) this precursor incorporated an ethylene sulfide molecule to obtain the surface denoted Sil-SSH. This material was characterized by elemental analysis, IR spectroscopy, thermogravimetry, solid state 13C and 29Si NMR, and surface area measurement. These materials were employed as adsorbents for divalent heavy cations from aqueous solutions at room temperature and the isotherms were adjusted to a modified Langmuir equation. The maxima number of moles adsorbed were 1.0, 1.5, 1.6, 2.2, 2.4 and 3.3 mmol g(-1) for Co, Cu, Ni, Cd, Pb, and Hg, respectively.     

Evaluation of filter-based aerosol measurements during the 1987 Southern California Air Quality Study

The Southern California Air Quality Study (SCAQS) was conducted during the summer and fall of 1987 to assess the causes of elevated ozone and suspended particulate matter concentrations in California's South Coast Air Basin (SoCAB). Extensive gaseous (i.e. nitric acid, ammonia, sulfur dioxide) and particle (i.e. PM_2.5 and PM₁₀ mass, elements, ions, carbon) measurements were acquired for 11 days during the summer at nine locations, and six days during the fall at six locations. Outliers were identified so that they could be excluded from further statistical analyses. Carbon and elemental measurements were found to be negatively biased by 20% owing to inhomogenous aerosol deposits on the SCAQS filters and analysis methods which were applied to a portion of the filters. These biases seem relatively consistent, however, and should not affect conclusions drawn from data analysis efforts if they are appropriately considered. Significant fractions (30–60%) of ammonium nitrate volatilized during the summer when temperatures were higher. Less than 10% typically volatilized during the fall when temperatures were lower. Anion/cation balances support the accuracy and precision estimates of the nitrate, sulfate, and ammonium measurements. Coarse particle sulfate was generally low, while coarse particle nitrate was most pronounced at the coastal sites.This paper documents SCAQS filter-based aerosol measurement methods, and evaluates the accuracy, precision, and validity of the data set. Various comparisons were made for: (1) PM_2.5/PM₁₀ ratios for mass and major chemical species; (2) sum of chemical species versus measured mass; (3) sulfate versus sulfur ratios; (4) PM_2.5 particulate nitrate versus nitric acid-denuded nitrate; and (5) anion/cation balances. The measurement and evaluation techniques presented in this paper serve as a guideline for other data analysis and modeling studies.     

Airborne and allergenic fungal spores of the Karachi environment and their correlation with meteorological factors

Airborne fungal spores are well known to cause respiratory allergic diseases particularly bronchial asthma, allergic rhinitis, rhino-conjunctivitis and allergic broncho-pulmonary aspergillosis in both adults and children. In order to monitor and analyze airborne fungal flora of the Karachi environment, an aeromycological study was conducted using a Burkard 7-Day Recording Volumetric Spore Trap from January to December 2010. The data recorded from the Spore Trap was further analyzed for percent catch determination, total spores concentration, seasonal periodicities and diurnal variations. Cladosporium spp (44.8%), Alternaria spp. (15.5%), Periconia spp (6.1%), Curvularia spp (2.1%), Stemphylium spp (1.3%) and Aspergillus/Penicillium type (1%) emerged to be major components constituting more than 70% of the airborne fungal flora. Cladosporium, Curvularia and Stemphylium displayed a clear seasonal trend, while there were no clear seasonal trends for other fungal spore types. Diurnal variations were observed to be mainly having daytime maxima. Spearman Rank Correlation Coefficient analysis was conducted using various weather parameters. The various fungal types showed a negative correlation with heat index, dew point, wind velocity and wind chill. However, a positive correlation was found with humidity, rain and barometric pressure. In fact, Alternaria, Bipolaris and Periconia showed a negative correlation with temperature, while Cladosporium and Periconia showed a negative correlation with heat index, dew point, wind velocity and wind chill. The barometric pressure was positively correlated with Cladosporium. On the basis of these findings, it can be concluded that a number of fungal spores are present in the atmosphere of Karachi throughout the year, with certain atmospheric conditions influencing the release, dispersion, and sedimentation processes of some genera. It is expected that clinicians will use the identified fungal flora for diagnosis and treatment and/or adopt preventative measures for allergic individuals.     

Risk assessment near uncontrolled hazardous waste sites: Role of monitoring data

The traditional approach of coupling estimates of human exposures to individual chemicals with laboratory studies of the toxicity of the chemicals as the basis for quantitative assessments of risk is not adequate when considering problems near hazardous waste sites. For example, there are (a) too many chemicals and mixtures involved, (b) containment uncertainties, and (c) future exposure problems associated with groundwater and soil contamination. Among the items to be considered in expanding the dimensions of risk assessment methodologies of the past are (a) identification of chemical groups or of dominant toxic chemicals of principal concern and the likely man-made as well as natural pathways for environmental migration, (b) the role of biological monitoring in addition to traditional monitoring approaches, and (c) the coupling of monitoring data with past, current, and future population activity patterns and with epidemiological and other health data.Monitoring data is a key in risk assessments since there is little likelihood that materials balances or modelling will provide authoritative information concerning exposure levels. The use of monitoring data from control areas and from nationwide baseline surveys in developing comparative risk assessments is particularly important. Finally, recent experience provides us with a number of practical guidelines for designing and carrying out monitoring programs that will provide authoritative and useful data. *** DIRECT SUPPORT *** AZ802019 00002     

Identification of new photoreduction products of pentachlorophenol

Pentachlorophenol (PCP), a fungicide and insecticide, leaves behind considerable residue in the environment in the form of unreacted molecule, metabolites and photoreduction products. Most of the previously reported photoproducts have resulted from dechlorination of the parent molecule. We have shown that photoreduction of PCP also proceeds by photoreduction of the parent molecule at carbons 2 and 4. These products were identified and characterized as 2-dehydro-2,3,4,5,6-pentachlorocyclohexanone (II) and 2,3,4,5,6-pentachlorocyclohexanone (IV). Both of them display keto-enol tautomerism. Identification and characterization of new photoproducts of PCP is significant for determining its overall environmental impact in the ecosystem.     

Meteorological influence on predicting surface SO2 concentration from satellite remote sensing in Shanghai,China

In this study, we explored the potential applications of the Ozone Monitoring Instrument (OMI) satellite sensor in air pollution research. The OMI planetary boundary layer sulfur dioxide (SO₂_PBL) column density and daily average surface SO₂ concentration of Shanghai from 2004 to 2012 were analyzed. After several consecutive years of increase, the surface SO₂ concentration finally declined in 2007. It was higher in winter than in other seasons. The coefficient between daily average surface SO₂ concentration and SO₂_PBL was only 0.316. But SO₂_PBL was found to be a highly significant predictor of the surface SO₂ concentration using the simple regression model. Five meteorological factors were considered in this study, among them, temperature, dew point, relative humidity, and wind speed were negatively correlated with surface SO₂ concentration, while pressure was positively correlated. Furthermore, it was found that dew point was a more effective predictor than temperature. When these meteorological factors were used in multiple regression, the determination coefficient reached 0.379. The relationship of the surface SO₂ concentration and meteorological factors was seasonally dependent. In summer and autumn, the regression model performed better than in spring and winter. The surface SO₂ concentration predicting method proposed in this study can be easily adapted for other regions, especially most useful for those having no operational air pollution forecasting services or having sparse ground monitoring networks.