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871.
Surface runoff is one of the most important pathways for pesticides to enter surface waters. Mathematical models are employed to characterize its spatio-temporal variability within landscapes, but they must be simple owing to the limited availability and low resolution of data at this scale. This study aimed to validate a simplified spatially-explicit model that is developed for the regional scale to calculate the runoff potential (RP). The RP is a generic indicator of the magnitude of pesticide inputs into streams via runoff. The underlying runoff model considers key environmental factors affecting runoff (precipitation, topography, land use, and soil characteristics), but predicts losses of a generic substance instead of any one pesticide. We predicted and evaluated RP for 20 small streams. RP input data were extracted from governmental databases. Pesticide measurements from a triennial study were used for validation. Measured pesticide concentrations were standardized by the applied mass per catchment and the water solubility of the relevant compounds. The maximum standardized concentration per site and year (runoff loss, RLoss) provided a generalized measure of observed pesticide inputs into the streams. Average RP explained 75% (p < 0.001) of the variance in RLoss. Our results imply that the generic indicator can give an adequate estimate of runoff inputs into small streams, wherever data of similar resolution are available. Therefore, we suggest RP for a first quick and cost-effective location of potential runoff hot spots at the landscape level. 相似文献
872.
We determined the maximum amounts of added phenanthrene, chrysene, and 2,5-dichlorobiphenyl sorbed onto high-energy adsorption sites in a sediment on bi-solute experiments. The bi-solute pairs were phenanthrene/chrysene and phenanthrene/2,5-dichlorobiphenyl. On the bi-solute sorption experiments, one solute was introduced and equilibrated with sediment prior to addition of the second solute. The values for the maximum amounts adsorbed onto high-energy sites revealed that, after equilibration of the first solute, still some high-energy sites could be occupied by the second solute. Phenanthrene, chrysene, and 2,5-dichlorobiphenyl seem to share about 30% of the accessible high-energy adsorption sites in the sediment employed. 相似文献
873.
Thacker NP Nitnaware VC Das SK Devotta S 《Environmental science and pollution research international》2007,14(4):225-226
Samples of effluents, sludge, pulp, final products (paper) and soil were collected from the identified pulp and paper mills
in India. The samples were analysed for 2,3,7,8-tetrachloro-dibenzo-p-dioxin (2,3,7,8-TCDD) and other dioxin congeners and
precursors. Pulp and paper mills using chlorine for the bleaching process showed the presence of 2,3,7,8-TCDD in effluent
samples. In the effluent and pulp samples from mills where chlorine dioxide was used as a bleaching agent, the 2,3,7,8-TCDD
congener ranged from below the detection limit 0.05 to 0.12 ngL−1/ngg−1. The relative standard deviation of reproducibility and the percent recovery of 2,3,7,8-TCDD were 2.07 and 82.4% in pulp
and 2.8 and 92% in effluent, respectively. The 1,3,6,8-TCDD was the only other major dioxin congener found in the treated
and untreated effluent and sludge samples. However, dichlorobenzene, trichlorophenyl, and hexachlorobiphenyl were detected
in all samples. The formation of dioxins can be minimised by replacing chlorine with chlorine dioxide in bleaching processes
in pulp and paper mills. 相似文献
874.
Paz-Alberto AM Sigua GC Baui BG Prudente JA 《Environmental science and pollution research international》2007,14(7):498-504
Background, Aims and Scope The global problem concerning contamination of the environment as a consequence of human activities is increasing. Most of
the environmental contaminants are chemical by-products and heavy metals such as lead (Pb). Lead released into the environment
makes its way into the air, soil and water. Lead contributes to a variety of health effects such as decline in mental, cognitive
and physical health of the individual. An alternative way of reducing Pb concentration from the soil is through phytoremediation.
Phytoremediation is an alternative method that uses plants to clean up a contaminated area. The objectives of this study were:
(1) to determine the survival rate and vegetative characteristics of three grass species such as vetivergrass, cogongrass
and carabaograss grown in soils with different Pb levels; and (2) to determine and compare the ability of the three grass
species as potential phytoremediators in terms of Pb accumulation by plants.
Methods The three test plants: vetivergrass (Vetiveria zizanioides L.); cogongrass (Imperata cylindrica L.); and carabaograss (Paspalum conjugatum L.) were grown in individual plastic bags containing soils with 75 mg kg−1 (37.5 kg ha−1) and 150 mg kg−1 (75 kg ha−1) of Pb, respectively. The Pb contents of the test plants and the soil were analyzed before and after experimental treatments
using an atomic absorption spectrophotometer. This study was laid out following a 3 × 2 factorial experiment in a completely
randomized design.
Results On the vegetative characteristics of the test plants, vetivergrass registered the highest whole plant dry matter weight (33.85–39.39
Mg ha−1). Carabaograss had the lowest herbage mass production of 4.12 Mg ha−1 and 5.72 Mg ha−1 from soils added with 75 and 150 mg Pb kg−1, respectively. Vetivergrass also had the highest percent plant survival which meant it best tolerated the Pb contamination
in soils. Vetivergrass registered the highest rate of Pb absorption (10.16 ± 2.81 mg kg−1). This was followed by cogongrass (2.34 ± 0.52 mg kg−1) and carabaograss with a mean Pb level of 0.49 ± 0.56 mg kg−1. Levels of Pb among the three grasses (shoots + roots) did not vary significantly with the amount of Pb added (75 and 150
mg kg−1) to the soil.
Discussion Vetivergrass yielded the highest biomass; it also has the greatest amount of Pb absorbed (roots + shoots). This can be attributed
to the highly extensive root system of vetivergrass with the presence of an enormous amount of root hairs. Extensive root
system denotes more contact to nutrients in soils, therefore more likelihood of nutrient absorption and Pb uptake. The efficiency
of plants as phytoremediators could be correlated with the plants’ total biomass. This implies that the higher the biomass,
the greater the Pb uptake. Plants characteristically exhibit remarkable capacity to absorb what they need and exclude what
they do not need. Some plants utilize exclusion mechanisms, where there is a reduced uptake by the roots or a restricted transport
of the metals from root to shoots. Combination of high metal accumulation and high biomass production results in the most
metal removal from the soil.
Conclusions The present study indicated that vetivergrass possessed many beneficial characteristics to uptake Pb from contaminated soil.
It was the most tolerant and could grow in soil contaminated with high Pb concentration. Cogongrass and carabaograss are also
potential phytoremediators since they can absorb small amount of Pb in soils, although cogongrass is more tolerant to Pb-contaminated
soil compared with carabaograss. The important implication of our findings is that vetivergrass can be used for phytoextraction
on sites contaminated with high levels of heavy metals; particularly Pb.
Recommendations and Perspectives High levels of Pb in localized areas are still a concern especially in urban areas with high levels of traffic, near Pb smelters,
battery plants, or industrial facilities that burn fuel ending up in water and soils. The grasses used in the study, and particularly
vetivergrass, can be used to phytoremediate urban soil with various contaminations by planting these grasses in lawns and
public parks.
ESS-Submission Editor: Dr. Willie Peijnenburg (wjgm.peijnenburg@rivm.nl) 相似文献
875.
Figueiredo AM Nogueira CA Saiki M Milian FM Domingos M 《Environmental pollution (Barking, Essex : 1987)》2007,145(1):279-292
Tillandsia usneoides L. is an epiphytic bromeliad plant able to absorb water and nutrients directly from the air. For this reason this species was selected to carry out a monitoring study of air pollution in the metropolitan region of S?o Paulo, Brazil. Five consecutive transplantation experiments (8 weeks each) were performed in 10 sites of the city, submitted to different sources of air pollution (industrial, vehicular), using plants collected from an unpolluted area. After exposure, trace metals were analyzed in the plant by instrumental neutron activation analysis. Traffic-related elements such as Zn and Ba presented high concentrations in exposure sites near to heavy traffic avenues (cars, buses and trucks) and may be associated to vehicular sources. For Zn and Co the highest contents were related to industrial zones and can be associated to the presence of anthropogenic emission sources. The rare earth elements, Fe and Rb, probably have soil particles as main source. 相似文献
876.
Frati L Santoni S Nicolardi V Gaggi C Brunialti G Guttova A Gaudino S Pati A Pirintsos SA Loppi S 《Environmental pollution (Barking, Essex : 1987)》2007,146(2):311-316
Effects of high ammonia emissions and nitrogen deposition were investigated on lichens around a pig stockfarm (ca. 7,000 animals) in central Italy. Four sites were selected along a transect at 200, 400, 1000 and 2500 m from the stockfarm, the diversity of epiphytic lichens was measured and transplanted thalli of Xanthoria parietina and Flavoparmelia caperata exposed, together with passive NH3 (diffusion tubes) samplers. Ammonia dramatically decreased from the centre of the stockfarm to the sampled sites, where it was correlated with bark pH. Total lichen diversity was not associated with either NH3 concentrations or bark pH, but the diversity of strictly nitrophytic species was highly correlated with both parameters. Physconia grisea was the best indicator species for NH3 pollution. Total N accumulated in X. parietina and F. caperata was correlated with NH3 concentrations. 相似文献
877.
Murciego AM Sánchez AG González MA Gil EP Gordillo CT Fernández JC Triguero TB 《Environmental pollution (Barking, Essex : 1987)》2007,145(1):15-21
A study about topsoil antimony distribution and mobility from the soils to the biomass has been afforded in three abandoned Sb mining areas located at Extremadura. Physico-chemical characteristics of the soils and total antimony levels were measured in soils and autochthonous plant species (Cytisus striatus, Cistus ladanifer and Dittrichia viscosa). Comparison with corresponding values in reference areas isolated from the mining activities is discussed. Antimony mobility in the soils was estimated by measuring the water extractable fraction; low results were obtained for the three soil areas, with no statistical differences. Plant ability to accumulate antimony was estimated by use of plant accumulation coefficients (PAC). Seasonal (spring vs. autumn) effects on the antimony content in the plant species. Cytisus striatus from Mari Rosa mine presented antimony excluder characteristics, whereas Dittrichia viscosa specimens growing in San Antonio mine showed a significant antimony bioaccumulation. 相似文献
878.
Kröger R Holland MM Moore MT Cooper CM 《Environmental pollution (Barking, Essex : 1987)》2007,146(1):114-119
The beneficial uptake of nutrients by wetland plants is countered to some extent by nutrient release back into the aquatic environment due to vegetative die-back. This current study examined whether Leersia oryzoides, a common wetland plant, exhibits luxury uptake of nutrients from simulated farm runoff. The study also tested whether with subsequent decomposition, these nutrients are released back into the water column. When exposed to elevated (>2mg/L N and P) runoff, L. oryzoides assimilated significantly higher concentrations of nitrogen (p<0.001) and phosphorus (p<0.001) in above-ground biomass as compared to non-enriched treatments (<0.05 mg/L N and P). Subsequently, senescence of enriched above-ground biomass yielded significantly higher concentrations of phosphorus (2.19+/-0.84 mg P/L). Using L. oryzoides as our model, this study demonstrates nitrogen and phosphorus sequestration during the growing season and release of phosphorus in the winter. 相似文献
879.
Bhattacharyya P Chakrabarti K Chakraborty A Nayak DC Tripathy S Powell MA 《Chemosphere》2007,66(9):1789-1793
The importance of the use of potassium in agriculture is increasing in South Asia for making most productive use of the nutrient in terms of economic returns. Nutrient supply traditionally by cattle manure is constrained by its insufficient availability. Municipal waste compost may be an alternative source of nutrient supplements. Field experiments were conducted at the Experimental Farm of Calcutta University, West Bengal, India during the wet seasons of 1997, 1998 and 1999 on flooded lowland rice. Potassium fractions in municipal waste compost and cattle manure were determined by sequential extraction and also the potassium uptake by rice to compare the effectiveness of municipal waste compost with traditional manure. Potassium was significantly bound to the organic matter in municipal waste compost. Potassium uptake by rice grain and straw increased significantly with the combined application of organics and fertilizers and it was higher in grain than in straw. Water-soluble and non-exchangeable potassium contents of municipal waste compost and cattle manure were highly correlated with the uptake of potassium by straw and grain. Exchangeable and residual potassium were also significantly correlated with the uptake of potassium by straw and grain of rice. Much higher uptake of K in rice straw and rain resulted from applying the manures in conjunction with fertilizers than when applied singly. 相似文献
880.
Dietz R Rigét FF Sonne C Letcher RJ Backus S Born EW Kirkegaard M Muir DC 《Environmental pollution (Barking, Essex : 1987)》2007,146(1):166-173
Polybrominated diphenyl ethers (PBDEs) were analysed in adipose tissue from 92 East Greenland polar bears (Ursus maritimus) sampled during 1999-2001. Mean SigmaPBDE concentrations were 70 ng/g lipid weight (lw) (range: 22-192 ng/g lw) and showed no relationship with age or sex. Of the 32 analysed PBDE congeners; BDE47, BDE153, BDE99 and BDE100 dominated, and comprised 99.6% of the SigmaPBDE concentration. The SigmaPBDE concentration had a highly significant correlation with SigmaPCB, SigmaCHL, dieldrin, HCB and SigmaHCH concentrations. We found a seasonal pattern of median SigmaPBDE concentration with 1.2 to 1.8 times higher concentrations in March to July than the rest of the year. The seasonal variation also provides a clue to the seasonal exposure, bio-availability, toxic exposure and degradation. We suggest that future geographical PBDE data comparisons may not need corrections for sex or age, but such data sets should be corrected for seasonal variability, using the presented correctional trigonometric regression. 相似文献