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1.
Elemental analyses (C, N, P, K) of invertebrate soil animals Contents of C, N, P and K were analysed in the dry matter of 14 soil organisms (13 species of animals + cysts of protozoa + 1 phytoflagellate) as well as the contents in C and N of further 9 animal species. The investigated material was partly collected in the field, partly raised in laboratory cultures. On the basis of similar C-contens, the investigated organisms may be classified into 4 groups: (1) snails (with shell) 18,3–20,7% C, (2) myriopodes and isopodes 30,3–34,1% C, (3) protozoa, nematodes and oligochaetes 41,2–49,5% C, (4) insects (adult) 48,4–53,3% C. The chemical composition of the organisms is discussed and possible causes of fluctuating concentrations are indicated.  相似文献   

2.
The present study evaluated the short-term toxicity of seven selected pesticides: four insecticides (chlorpyrifos, dieldrin, diazinon and pirimiphos-methyl) and three herbicides (diuron, alachlor and atrazine). With this aim, a standard toxicity test with the highly sensitive early life stages (ELS) of a marine fish was used. The turbot, Psetta maxima, is abundant in shallow estuarine and costal habitats and is currently the most commonly cultivated fish species in Galicia, NW Spain. According to the turbot ELS test results, chlorpyrifos was the most toxic pesticide tested for both embryos and larvae and was followed in order of decreasing toxicity by dieldrin, pirimiphos-methyl, diazinon, alachlor, atrazine and diuron. Larvae were more sensitive than embryos to the seven pesticides. The median lethal concentrations of the selected pesticides during a 48- and a 96-h exposure for turbot embryos and larvae were, respectively (in micrograms per litre): chlorpyrifos, 116.6 and 94.65; dieldrin, 146 and 97; pirimiphos-methyl, 560 and 452; diazinon, 1,837 and 1,230; alachlor, 2,177 and 2,233; diuron, 10,076 and 7,826; and atrazine, 11,873 and 9,957. According to their acute toxicity, the insecticides were more toxic than the herbicides. Furthermore, all insecticides and herbicides appear to be teratogenic to turbot ELS.  相似文献   

3.
Studies were conducted during the period May 1993 to April 1994 on the density, biomass and vertical distribution ofAporrectodea caliginosa, a common species of earthworm found in the Benena farms in Benghazi, Libya. The soil of the farm was a clay loam, pH 7.3, and the organic matter averaged 4.2%. Maximum density and biomass ofA. caliginosa were recorded from October to December 1993 and again during March and April 1994, and minimum values were recorded from May to July 1993. A juvenile dominant population was observed during the summer. This was followed by an increase in subadults and adults during the autumn, winter and spring seasons. A positive correlation of the moisture and an inverse correlation of soil temperature on the density and biomass of these animals were discernible. A. caliginosa mainly confined their activities to the surface organic zone (0–10 cm depth) of the soil for most of the months studied.  相似文献   

4.
Photolysis, sonolysis, and photosonolysis of common groundwater contaminants, namely 1,1,1-trichloroethane, trichloroethylene, and tetrachloroethylene, were investigated using a flow-through photosono reactor system. Simulated groundwater containing the chlorinated volatile organic compounds (VOCs) was exposed to ultraviolet light (UV), ultrasonication (US), and UV and US concurrently (UVUS), without a photo catalyst. VOC removal efficiencies of the UV, US, and UVUS treatment processes were computed from the VOC concentrations in influent and effluent of the reactor. The process using UVUS exhibited larger degradation efficiencies than that with UV and US separately in most cases; however, statistical analysis showed that the UVUS treatment efficiency is likely to be additive of the UV and US treatment efficiencies. The results also showed that the increase of the detention time from 26 to 60 min had no significant effect on the VOC removal efficiencies in these processes.  相似文献   

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Vegetated drainages are an effective method for removal of pollutants associated with agricultural runoff. Leersia oryzoides, a plant common to agricultural ditches, may be particularly effective in remediation; however, research characterizing responses of L. oryzoides to flooding are limited. Soil reduction resulting from flooding can change availability of nutrients to plants via changes in chemical species (e.g., increasing solubility of Fe). Additionally, plant metabolic stresses resulting from reduced soils can decrease nutrient uptake and translocation. The objective of this study was to characterize belowground and aboveground nutrient allocation of L. oryzoides subjected to various soil moisture regimes. Treatments included: a well-watered and well-drained control; a continuously saturated treatment; a 48-h pulse-flood treatment; and a partially flooded treatment in which water level was maintained at 15 cm below the soil surface and flooded to the soil surface for 48 h once a week. Soil redox potential (Eh, mV) was measured periodically over the course of the 8-week experiment. At experiment termination, concentrations of Kjeldahl nitrogen, phosphorus (P), potassium (K), iron (Fe), and manganese (Mn) were measured in plant tissues. All flooded treatments demonstrated moderately reduced soil conditions (Eh < 350 mV). Plant Kjeldahl nitrogen concentrations demonstrated no treatment effect, whereas P and K concentrations decreased in aboveground portions of the plant. Belowground concentrations of P, Mn, and Fe were significantly higher in flooded plants, likely due to the increased solubility of these nutrients resulting from the reductive decomposition of metal–phosphate complexes in the soil and subsequent precipitation in the rhizosphere. These results indicate that wetland plants may indirectly affect P, Mn, and Fe concentrations in surface waters by altering local trends in soil oxidation–reduction chemistry.  相似文献   

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The Mar Piccolo (surface area of 20.72 km2) is located in the Northern area of the Taranto town (Ionian Sea, Italy). It is an inner, semi-enclosed basin with lagoon features connected with the Mar Grande through two channels which are very important for water exchange. Mar Piccolo basin is subjected to urbanization, industry, agriculture, aquaculture and commercial fishing. Hence, it is important to have a temporal picture both of heavy metal content and of organic carbon and their distribution (hydrophobic fraction, hydrophilic fraction, humic compounds) to check the progress of pollution in time. Three sediment cores collected on the basis of the pollution sources have been analyzed. Both heavy metal and organic carbon concentrations underline the fact that the anthropogenic input is different in the three sites, and that in time the amount of pollutants coming into the Mar Piccolo have changed in different ways. The high amount of organic hydrophilic compounds present in sediments, both due to the small water depth and to the high accumulation rate, make the sediment site high in oxygen consumption due to a considerable chemical and biochemical transformations of organic matter.  相似文献   

9.
The contents of heavy alkaline-earth (Sr and Ba) and rare-earth (Y, La, and Ce) metals have been studied in two technogeochemical anomalies and in the soils of Perm and Chusovoi. The soils are contaminated with barium, lanthanum, and cerium in the territory of the Cherepovets technogeochemical anomaly formed due to the atmospheric emissions from the Severstal metallurgical works. Strontium, barium, and yttrium are accumulated in the soils of the Revda technogeochemical anomaly formed by aerial emissions from the Mid-Urals copper smelter. The portion of technogenic strontium reaches 43–84% near the metallurgical works, while that of barium and yttrium, 47–63 and 28–32%, respectively. In Perm, the urban soils are polluted with technogenic alkaline-earth metals, i.e., strontium and barium, with their content reaching 31–48%. In Chusovoi, the calcareous horizons of the soddy soils are enriched in strontium and depleted in barium. The eluvial-illuvial distribution of the rare-earth metals is registered in the soddy-podzolic soil. The soils of the terrace are contaminated with barium. The technozem is contaminated with all the metals (barium and yttrium, in particular).  相似文献   

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Studies were conducted during the period May 1993 to April 1994 on the density, biomass and vertical distribution ofAporrectodea caliginosa, a common species of earthworm found in the Benena farms in Benghazi, Libya. The soil of the farm was a clay loam, pH 7.3, and the organic matter averaged 4.2%. Maximum density and biomass ofA. caliginosa were recorded from October to December 1993 and again during March and April 1994, and minimum values were recorded from May to July 1993. A juvenile dominant population was observed during the summer. This was followed by an increase in subadults and adults during the autumn, winter and spring seasons. A positive correlation of the moisture and an inverse correlation of soil temperature on the density and biomass of these animals were discernible. A. caliginosa mainly confined their activities to the surface organic zone (0–10 cm depth) of the soil for most of the months studied.  相似文献   

14.
The effect of Cl?,SO 4 2? , CH3COO?, and NO 3 ? anions on the adsorption of copper, lead, and zinc by an ordinary chernozem has been studied. The effect of the anions on the adsorption of Cu2+, Pb2+, Zn2+ ions is significant but uncertain. It has been shown that the attendant anions affect the shape of the adsorption isotherms, which are described by the Langmuir, Freundlich, or Henri equations. The constants of the adsorption from a nitrate solution calculated from the Langmuir equation (K L) decrease in the following order: Cu2+ > Pb2+ >> Zn2+. The values of the maximum adsorption (C max) decrease in the following order: Cu2+ ≥ Zn2+ > Pb2+ for acetate solutions and in the series Pb2+ > Zn2+ ≥ Cu2+ for nitrate solutions. The values of the Henry constants (K H) calculated for the adsorption of the same cations from chloride solutions decrease in the same order as the values of K L. The CH3COO? anion has the highest effect on the constant values. The NO 3 ? and Cl? anions “switch their places” depending on the attendant cation, but their effect is always lower than that of the acetate anion. The values of C max for copper and zinc are most affected by the CH3COO? anion, and the adsorption of zinc is most affected by the Cl? and NO 3 ? anions. The assessment of the mobility of the adsorbed cations from the extraction with ammonium acetate (pH 4.8) has shown that the content of the desorbed metals is always lower than the content of the adsorbed cations and varies from 0.025 to 83%. According to their mobility, the adsorbed metals form the following order: Zn2+ > Pb2+ > Cu2+. The effect of the attendant anions on the extractability of the adsorbed cations decreases in the following order: chlorides > sulfates > acetates > nitrates.  相似文献   

15.
Concentrations of PCBs, PCDDs, and PCDFs, heavy metals (Cu, Cd, Zn, Pb, and Hg), and arsenic have been determined in a great variety of food samples purchased in different markets across the city of Huelva, located in southwestern Spain and under strong industrial activity. All samples analyzed presented concentrations below the maximum allowed by the European Community regarding PCDD/Fs, with the exception of samples within the meat group. An estimation of the daily intake resulted in 1.15 pg of WHO(PCDD/Fs)-TEQ/kg of body weight/day for a 70 kg person and 2.63 pg of WHO-TEQ/kg of body weight/day when PCBs were included, therefore accounting for a similar or even higher percentage than PCDD/Fs and showing the importance of their inclusion in monitoring studies. Meat and meat products, together with vegetable oils and dairy products, were the major food groups contributing to the estimated daily intake. For heavy metals and arsenic, the concentrations found were under the value proposed by European regulations, and estimated daily intakes were well below those proposed by the WHO for all metals investigated. PAHs have been analyzed in food samples from marine origin, values ranging from 8.22 to 71.4 ng/g of fresh weight. Pyrene was the most abundant compound, accounting for >80% in the samples investigated. The most carcinogenic PAHs, such as benzo[a]pyrene and dibenz[a,h]anthracene, were in all cases below the limits of detection. Therefore, the samples analyzed in this survey can be considered as safe with regard to the levels obtained and the in-force legislation.  相似文献   

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To study the antioxidant activity of quince fruit (pulp, peel, and seed) and jam, methanolic extracts were prepared. Each extract was fractionated into a phenolic fraction and an organic acid fraction and was analyzed by high-performance liquid chromatography (HPLC)/diode array detection and HPLC/UV, respectively. Antiradical activities of the extracts and fractions were evaluated by a microassay using 1,1'-diphenyl-2-picrylhydrazyl. The phenolic fraction always exhibited a stronger antioxidant activity than the whole methanolic extract. Organic acid extracts were always the weakest in terms of antiradical activity, which seems to indicate that the phenolic fraction gives a higher contribution for the antioxidant potential of quince fruit and jam. The evaluation of the antioxidant activity of methanolic extracts showed that peel extract was the one presenting the highest antioxidant capacity. The IC50 values of quince pulp, peel, and jam extracts were correlated with the caffeoylquinic acids total content. Among the phenolic fractions, the seed extract was the one that exhibited the strongest antioxidant activity. The IC50 values of quince pulp, peel, and jam phenolic extracts were strongly correlated with caffeoylquinic acids and phenolics total contents. For organic acid fractions, the peel extract was the one that had the strongest antiradical activity. The IC50 values of quince pulp, peel, and jam organic acid fractions were correlated with the ascorbic acid and citric acid contents.  相似文献   

18.
Brassicaceae seed meals produce ionic thiocyanate (SCN (-)), a bioherbicidal compound. This study determined the fate of SCN (-) in a field soil amended with seed meals of Sinapis alba, Brassica juncea, and Brassica napus and quantified crop phytotoxicity by monitoring carrot ( Daucus carota) emergence. Meals were applied at 1 or 2 t ha (-1), and soils were sampled to 35 cm for SCN (-). Maximum SCN (-) (211 micromol kg (-1) of soil) was measured at 5 days in 0-5 cm samples from plots amended with S. alba meal at 2 t ha (-1). Less than 30 micromol of SCN (-) kg (-1) of soil was measured at soil depths below 15 cm. At 44 days, SCN (-) was <15 micromol kg (-1) of soil in all treatments. Emergence inhibition of carrots seeded 15-36 days after meal amendment was found only in S. alba treatments. The rapid decrease of SCN (-) concentrations in Brassicaceae meal-amended soil indicates limited potential for off-site environmental impacts.  相似文献   

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European, small-fruited cranberries (Vaccinium microcarpon) and lingonberries (Vaccinium vitis-idaea) were characterized for their phenolic compounds and tested for antioxidant, antimicrobial, antiadhesive, and antiinflammatory effects. The main phenolic compounds in both lingonberries and cranberries were proanthocyanidins comprising 63-71% of the total phenolic content, but anthocyanins, hydroxycinnamic acids, hydroxybenzoic acids, and flavonols were also found. Proanthocyanidins are polymeric phenolic compounds consisting mainly of catechin, epicatechin, gallocatechin, and epigallocatechin units. In the present study, proanthocyanidins were divided into three groups: dimers and trimers, oligomers (mDP 4-10), and polymers (mDP > 10). Catechin, epicatechin, A-type dimers and trimers were found to be the terminal units of isolated proanthocyanidin fractions. Inhibitions of lipid oxidation in liposomes were over 70% and in emulsions over 85%, and in most cases the oligomeric or polymeric fraction was the most effective. Polymeric proanthocyanidin extracts of lingonberries and cranberries were strongly antimicrobial against Staphylococcus aureus, whereas they had no effect on other bacterial strains such as Salmonella enterica sv. Typhimurium, Lactobacillus rhamnosus and Escherichia coli. Polymeric fraction of cranberries and oligomeric fractions of both lingonberries and cranberries showed an inhibitory effect on hemagglutination of E. coli, which expresses the M hemagglutin. Cranberry phenolic extract inhibited LPS-induced NO production in a dose-dependent manner, but it had no major effect on iNOS of COX-2 expression. At a concentration of 100 μg/mL cranberry phenolic extract inhibited LPS-induced IL-6, IL-1β and TNF-α production. Lingonberry phenolics had no significant effect on IL-1β production but inhibited IL-6 and TNF-α production at a concentration of 100 μg/mL similarly to cranberry phenolic extract. In conclusion the phenolics, notably proanthocyanidins (oligomers and polymers), in both lingonberries and cranberries exert multiple bioactivities that may be exploited in food development.  相似文献   

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