Oxidation and Removal of 1,2,4-Trichlorobenzene using Sodium Persulfate in a Sorption-Desorption Experiment     

Adam M. Barbash  George E. Hoag  Farhad Nadim 《Water, air, and soil pollution》2006,171(1-4):67-80

Peat soils with a gradient of naturally high Cd and Zn (up to 190 and 70,000,mg/kg, respectively) were sampled at several depths from a wetland overlying Zn-rich dolomitic bedrock. Total concentrations of Zn, Cd and S were generally much higher in the seasonally water-saturated subsoils than at the surface. Leaching studies with intact soil columns showed the subsoils generally have a greater tendency to release Zn, Cd and S than the topsoils. Zn and Cd leaching were correlated to sulfate dissolution, with 6 successive leaching events removing up to 4% and 13% of the total Zn and S, respectively, from the most metal-rich subsoils. Relative leaching losses were less from the surface soils, not exceeding 1% and 3% of total Zn and S. Because Zn was relatively more soluble and extractable by 0.01,M CaCl₂ than Cd, Zn/Cd ratios in column leachates and field-sampled groundwater were higher than the soil Zn/Cd ratios. Consequently, the potential for loss of Zn from the soil by leaching was higher than that of Cd, particularly from the subsoil. Nevertheless, some soil layers of the profile were enriched in total Zn relative to Cd, indicated by Zn/Cd ratios well above that of the Cd-rich sphalerite in the parent dolomitic rock. This enrichment may be explained by historical migration and re-immobilization of Zn as sulfides. The low solubility of Cd in the peats despite high total Cd suggests preferential immobilization of this metal by organic sulfur or sulfide.  相似文献   

Determination of oryzalin in water, citrus fruits, and stone fruits by liquid chromatography with tandem mass spectrometry     

West SD  Hastings MJ  Shackelford DD  Dial GE 《Journal of agricultural and food chemistry》2004,52(19):5781-5786

A new methodology is described for rapidly determining the herbicide oryzalin in water, citrus fruits, and stone fruits by liquid chromatography with negative ion electrospray ionization tandem mass spectrometry (LC/MS/MS). Oryzalin is extracted from water using a polymeric sorbent solid phase extraction (SPE) column and from fruit using methanol. The water samples require no further purification, but an aliquot of the fruit sample extracts is diluted with water and purified using a polymeric 96 well SPE plate. Purified extracts are concentrated prior to determination by LC/MS/MS at m/z 345 (Q1) and m/z 281 (Q3) using an external standard for calibration. The validated limits of quantitation were 0.05 microg/L in water (drinking water, surface water, and groundwater) and 0.01 microg/g in citrus fruits (oranges and lemons) and stone fruits (peaches and cherries). Recoveries averaged 102% for water samples and 85-89% for the various types of fruit samples. For all fortification levels combined, the relative standard deviations ranged from 4 to 6% for water and from 2 to 4% for fruit.  相似文献   

The influence of Gilberto Righi on tropical earthworm taxonomy: the value of a full-time taxonomist: The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002     

Carlos Fragoso  George Brown  Alexander Feijoo 《Pedobiologia》2003,47(5-6):400-404

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Carbohydrate composition of selected plum/prune preparations     

Dikeman CL  Bauer LL  Fahey GC 《Journal of agricultural and food chemistry》2004,52(4):853-859

Eighteen plum/prune preparations and byproducts were analyzed for proximate constituents and carbohydrate profiles. Plum puree and prune juice contained the highest concentrations of ash (13.0 and 13.8%, respectively). Crude protein (CP), acid-hydrolyzed fat (AHF), and total dietary fiber (TDF) concentrations were higher in byproducts (waste cake and dried plum pits) compared with the other fractions. Several classes of oligosaccharides were found in low concentrations in many of the substrates and were associated with the fruit rather than the pit. Maltooligosaccharides were found in very high concentrations in three of the preparations as a result of the addition of maltodextrin during processing. Monosaccharides, sugar alcohols, and oligosaccharides were found in higher concentrations in the fruit than in the pit and accounted for 2.9-84.7% of substrate organic matter. These results indicate that carbohydrates of various types constitute a significant proportion of plum/prune preparations and byproducts.  相似文献   

Detection and characterization of DNA adducts formed from metabolites of the fungicide ortho-phenylphenol     

Zhao S  Narang A  Gierthy J  Eadon G 《Journal of agricultural and food chemistry》2002,50(11):3351-3358

The significance of DNA adduction in ortho-phenylphenol-induced carcinogenesis remains unclear. Establishing adduct structures may contribute to resolving this issue. The chemical structures of the DNA adduction products resulting from the in vitro reaction of phenylbenzoquinone, the putative ultimate carcinogenic metabolite of the fungicide/disinfectant ortho-phenylphenol, are reported here. Three isomeric adducts that resulted from reaction of deoxyguanosine were characterized by UV, LC-ESI-MS, and MS/MS, and 1D and 2D COSY-NMR spectroscopy. The proposed mechanism of product formation is nucleophilic attack by the deoxyguanosine exocyclic amine nitrogen on an electrophilic quinone carbon, followed by stabilization through enolization. Another nucleophilic attack forms a five-membered ring, which aromatizes by dehydration to form the final product. Adducts were also characterized from deoxyadenosine and deoxycytidine, although conversions were at least 10 times lower. Structures are also proposed for these products. Cell culture studies confirmed that HepG2 cells incubated with phenylbenzoquinone at concentrations associated with cytotoxicity form the same DNA adducts.  相似文献   

Soil management options for Alfisols in the semi-arid tropics: annual and perennial crop production     

A. L. Cogle  K. P. C. Rao  D. F. Yule  P. J. George  S. T. Srinivasan  G. D. Smith  L. Jangawad 《Soil & Tillage Research》1997,44(3-4):235-253

A field experiment was conducted in the semi arid tropics to study the effects of soil structural modification on cropping systems. The aim was to improve crop production and land resource protection using innovative soil management practices. Tillage, mulch and perennial/annual rotational based systems were compared for 5 years in an Alfisol at ICRISAT in India. Crop yield parameters, including grain and biomass yield, leaf area index, crop cover, and plant height were measured. Results indicate significant benefits to annual crop yield (maize, sorghum) from improved water supply due to mulching with farmyard manure or and rice straw, and due to rotation with prior-perennial crops. Grain yields were 16 to 59% higher in mulched treatments compared to unmulched treatments, with similar increases for fodder yields. Annual crop yields after 4 years of perennials were 14 to 81% higher than unmulched treatments, except for low fertility maize grown after buffel grass. The interaction with chemical fertility was less clear than for water supply. The results have implications for soil management throughout the semi-arid tropics.  相似文献   

Sheld-geese and man in the Falkland Islands     

Ronald W. Summers  George M. Dunnet 《Biological conservation》1984,30(4):319-340

The history of the association between sheld-geese (upland geese Chloëphaga picta and ruddy-headed geese C. rubidiceps) and man in the Falkland Islands is described from the time when they were used as food by early settlers, to the conflict with the sheep industry. Geese were found to be extremely abundant when man first settled. A bounty scheme was instigated by sheep farmers in 1905 and claimed 74 000 geese annually between 1905 and 1912. Far fewer (25 000 annually) were killed in the late 1970s because fewer shepherds lived in the remote houses of sheep stations, and the bounty did not increase in proportion with wage increases. The population of geese remains large despite this toll and recent studies of the annual cycle, movements and population dynamics give reasons for the failure of the bounty scheme to reduce numbers. Information on food intake and densities of geese on different vegetation types has indicated that the geese populations take only 1·5% of the total annual organic matter production of herbage. This represents 7% of what is eaten by all the herbivores. However, most of this consumption is restricted to a few vegetation types with a relatively small area (e.g. ‘greens’ and reseeded pastures). It is the consumption from reseeds that causes the biggest problem to the sheep industry. Methods of control are discussed and the value of destruction of geese questioned.  相似文献   

Applying combinatorial chemistry and biology to food research   总被引：1，自引：0，他引：1  

Wong D  Robertson G 《Journal of agricultural and food chemistry》2004,52(24):7187-7198

In the past decade combinatorial chemistry has become a major focus of research activity in the pharmaceutical industry for accelerating the development of novel therapeutic compounds. The same combinatorial strategies could be applied to a broad spectrum of areas in agricultural and food research, including food safety and nutrition, development of product ingredients, and processing and conversion of natural products. In contrast to "rational design", the combinatorial approach relies on molecular diversity and high-throughput screening. The capability of exploring the structural and functional limits of a vast population of diverse chemical and biochemical molecules makes it possible to expedite the creation and isolation of compounds of desirable and useful properties. Several studies in recent years have demonstrated the utility of combinatorial methods for food research. These include the discovery of synthetic antimicrobial, antioxidative, and aflatoxin-binding peptides, the identification and analysis of unique flavor compounds, the generation of new enzyme inhibitors, the development of therapeutic antibodies for botulinum neurotoxins, the synthesis of unnatural polyketides and carotenoids, and the modification of food enzymes with novel properties. The results of such activities could open a large area of applications with potential benefits to the food industry. This review describes the current techniques of combinatorial chemistry and their applications, with emphasis on examples in food science research.  相似文献   

Prioritization of ground water contaminants and sources     

Associate Professor R. C. Knox  George Lynn Cross Research Professor  Sun Company Professor of Ground Water Hydrology  Director L. W. Canter 《Water, air, and soil pollution》1996,88(3-4):205-226

The objective of this research was to identify chemical, physical, bacteriological, and viral contaminants, and their sources, which present the greatest health threat in public ground water supplies in the USA; and to classify (prioritize) such contaminants and relative to their health concerns. The developed contaminant prioritization methodology was based on frequency of occurrence and adverse health effects. Adverse health effects were based on carcinogenic potency, toxicity, hazardous chemical priorities and drinking water standards. Application of the methodology for wellhead protection areas, (WHPAs) revealed that approximately 200 different contaminants have been detected in the nation's public ground water supplies. The seven chemical constituents with the highest priority were arsenic, chromium, cadmium, carbon tetrachloride, chloroform, 1, 1-dichloroethylene, and ethylene dibromide. Other contaminants of concern were trichloroethylene, nitrates, barium, 1,1,1-trichloroethane, benzene, tetrachloroethylene, selenium, lead, toluene, mercury, gross alpha radiation, methylene chloride, coliform bacteria, metolachlor, metribuzin, 1, 1, 2, 2-tetrachloroethane, dibromochloroethane, simazine, radium-266, and toxaphene. The contaminant source prioritization methodology was also based on frequency of occurrence. Over 30 categories of sources were evaluated, with the eight with highest priority including agricultural activities, hazardous waste sites, landfills, industrial operations, septic tank systems, oil and gas field activities, urban land use, and underground storage tanks.  相似文献   

Freshwater conservation planning in data-poor areas: An example from a remote Amazonian basin (Madre de Dios River, Peru and Bolivia)     

Michele Thieme  Bernhard Lehner  Robin Abell  George Powell 《Biological conservation》2007,135(4):484-501

Using the 160,000-km² drainage basin of the Madre de Dios and Orthon rivers in the southwest Amazon as a test case, we piloted an approach for large-scale conservation planning for freshwater systems characterized by a near-complete lack of biological and physical data. We used newly available spatial and remote sensing datasets, including spaceborne optical and radar observations, and new techniques of spatial data analysis to generate subbasin (?100 km²), stream, and floodplain and wetland habitat classifications. We then generated a preliminary plan for a network of conservation areas to protect the most intact examples of representative habitat types while maximizing longitudinal and lateral connectivity. Proposed additions for freshwater conservation complement existing reserves and build on earlier conservation planning efforts for terrestrial ecosystems. In the resulting integrated plan, at least 20% of the area of each major freshwater habitat type is represented and two continuous corridors exist from the mouth of the Madre de Dios to its headwaters in the Andes. In total, we highlighted 84 currently unprotected subbasins to fulfill our representation and connectivity goals. About two-thirds of these subbasins were considered relatively undisturbed and are identified as Level I (critical management zones) or Level II (indigenous territories), whereas one-third are potentially degraded and thus were designated as Level III (threat mitigation zones). This exercise provides an example of how newly available remote-sensing datasets and analytical tools may be used to advance freshwater conservation planning, particularly in data-poor regions.  相似文献