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161.
Nadia Waegeneers Teresa Sauras-Yera Yves Thiry V. Ramón Vallejo Erik Smolders Chantal Madoz-Escande François Bréchignac 《Journal of environmental radioactivity》2009
Uptake of 137Cs was measured in different agricultural plant species (beans, lettuce, barley and ryegrass) grown in 5 undisturbed soil monoliths covering major European soil types. The first cultivation was made three years after soil contamination and plants were grown during 3 successive years. The plant–soil 137Cs transfer factors varied maximally 12-fold among soils and 35-fold among species when grown on the same soil. Single correlations between transfer factors and soil properties were found, but they varied widely with plant type and can hardly be used as a predictive tool because of the few soils used. The variation of 137Cs concentrations in plants among soils was related to differences in soil solution 137Cs and K concentrations, consistent with previous observations in hydroponics and pot trials. Absolute values of transfer factors could not be predicted based on a model validated for pot trials. The 137Cs activity concentration in soil solution decreased significantly (11- to 250-fold) for most soils in the 1997–1999 period and is partly explained by decreasing K in soil solution. Transfer factors of lettuce showed both increasing and decreasing trends between 2 consecutive years depending on soil type. The trends could be explained by the variation in 137Cs and K concentrations in soil solution. It is concluded that differences in 137Cs transfer factors among soils and trends in transfer factors as a function of time can be explained from soil solution composition, as shown previously for pot trials, although absolute values of transfer factors could not be predicted. 相似文献
162.
Craig Loehle T. Bently Wigley Erik Schilling Vickie Tatum John Beebe Eric Vance Paul Van Deusen Philip Weatherford 《Environmental management》2009,44(6):1136-1148
Managed forests are a primary land use within the Coastal Plain of the southern United States. These forests are generally
managed under standards, guidelines, or regulations to conserve ecosystem functions and services. Economic value of commercial
forests provides incentives for landowners to maintain forests rather than convert them to other uses that have substantially
reduced environmental benefits. In this review, we describe the historical context of commercial forest management in the
southern United States Coastal Plain, describe how working forests are managed today, and examine relationships between commercial
forest management and maintenance of functional aquatic and wetland systems and conservation of biological diversity. Significant
challenges for the region include increasing human population and urbanization and concomitant changes in forest area and
structure, invasive species, and increased interest in forest biomass as an energy feedstock. Research needs include better
information about management of rare species and communities and quantification of relationships between ecosystem attributes
and forest management, including biomass production and harvest. Incentives and better information may help commercial forest
managers in the Coastal Plain more efficiently contribute to landscape-scale conservation goals. 相似文献
163.
164.
This article focuses on the ecological role of benthic macrofauna on nutrient dynamics and benthic-pelagic coupling in the Baltic Sea with relation to eutrophication. Generally, benthic macrofaunal activities have large effects on sediment biogeochemistry and often with stimulatory effects on processes that counteract eutrophication, i.e., denitrification and increased phosphorus retention of the sediment. The degree of faunal impact on such processes varies depending on faunal density and functional group composition. The effect of macrofaunal activities on sediment nutrient dynamics can also result in a higher nitrogen: phosporus ratio of the sediments efflux compared with sediments without macrofauna. Increased internal nutrient loading during eutrophication-induced anoxia is suggested to be caused both by altered sediment biogeochemical processes and through reduced or lost bioturbating macrofauna and thereby a reduced stimulatory effect from their activities on natural purification processes of the Baltic Sea ecosystem. 相似文献
165.
Erik J. van Waveren 《Natural resources forum》2007,31(3):188-197
This paper examines the effects of growing land pressure on the distribution and quality of cropland allocations on customary tenured land (CTL) in Swaziland. Within the wider Sub‐Saharan context, the reform of indigenous tenure systems is now generally seen as a process of adaptation rather than replacement. The legal recognition of (existing and future) user rights is considered a practical way forward. This essentially rights‐based approach may divert attention from technical inadequacies indigenous systems may have, particularly under conditions of increasing land pressure. The case of CTL substantiates such shortcomings. CTL has seen a marked growth in population and land allocations since Independence. This had led to concerns on the land distribution efficiency in view of the improved agricultural production required to sustain the increasing number of rural households. By analysing historical changes in the number, size and quality of cropland allocations in selected rural communities, this paper demonstrates the occurrence of a high degree of inconsistency in cropland distribution at the community level, as well as inefficient land distribution at higher levels of scale. These shortcomings threaten the sustainability of the local agricultural production systems, and will need to be addressed in any meaningful reform process. 相似文献
166.
167.
168.
Environmental risk assessment of phosphonates,used in domestic laundry and cleaning agents in The Netherlands 总被引:2,自引:0,他引:2
Jaworska J Van Genderen-Takken H Hanstveit A van de Plassche E Feijtel T 《Chemosphere》2002,47(6):655-665
In the long-term cooperative project Voluntary Plan of Action (1990) between the Dutch Soap and Detergent Association (NVZ) and the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM) environmental risk assessments of several main components of laundry cleaning formulations were completed. As a part of that project the environmental risk assessment of HEDP, ATMP, EDTMP and DTPMP phosphonates used in detergent applications has been carried out according to the EU Technical Guidance Document for Environmental Risk Assessment for New and Existing Chemicals. All PEC/PNEC ratios were well below 1. Results of this assessment based on the total industry volumes from 1995 and 1998 indicate that the environmental risk of these phosphonates is low in The Netherlands with properly functioning sewage treatment plants. 相似文献
169.
The effect of ageing on the bioavailability and sorption of the herbicides atrazine and mecoprop was studied in soil and aquifer chalk sampled at an agricultural field near Aalborg, Denmark. The herbicides were incubated in sterile soil or chalk up to 3 months prior to inoculation with 5 x 10(7) cells g(-1) (dry weight) of a mecoprop degrading highly enriched culture (PM) or 1 x 10(9) cells g(-1) (dry weight) of the atrazine degrading Pseudomonas sp. strain ADP. As a measure of the bioavailable residues accumulated 14CO2 was measured for 2 months. In both soil and chalk ageing limited the rate of atrazine mineralization, and in chalk the extent of mineralization was reduced as well. The fraction of sorbed atrazine in the soil ranged between 50% and 62%, whereas a maximum of 12% was sorbed in chalk. No impact on the mineralization of aged mecoprop was seen as no sorption of this herbicide on either soil or chalk was measured. 相似文献
170.
Shaobo Liang Armando G. McDonald Erik R. Coats 《Waste management (New York, N.Y.)》2014,34(11):2022-2027
Potato peel waste (PPW) as zero value byproduct generated from food processing plant contains a large quantity of starch, non-starch polysaccharide, lignin, protein, and lipid. PPW as one promising carbon source can be managed and utilized to value added bioproducts through a simple fermentation process using undefined mixed cultures inoculated from wastewater treatment plant sludge. A series of non-pH controlled batch fermentations under different conditions such as pretreatment process, enzymatic hydrolysis, temperature, and solids loading were studied. Lactic acid (LA) was the major product, followed by acetic acid (AA) and ethanol under fermentation conditions without the presence of added hydrolytic enzymes. The maximum yields of LA, AA, and ethanol were respectively, 0.22 g g?1, 0.06 g g?1, and 0.05 g g?1. The highest LA concentration of 14.7 g L?1 was obtained from a bioreactor with initial solids loading of 60 g L?1 at 35 °C. 相似文献