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101.
A. Schmauß 《Die Naturwissenschaften》1914,2(21):524-524
102.
103.
Dissolved organic matter (DOM) in soil solution is considered to interact with herbicides enhancing their mobility and promoting
subsequent leaching.
Batch experiments were conducted to test if free and DOM-bound herbicides can be separated by a DOM-flocculation technique
with Cu as a coagulant.
DOM was extracted from the H and A horizons of two soils (Terric Histosol, Cumuli-Calcaric Cambisol) and from the O horizon
of a forest soil (Humic Cambisol). DOM-solutions (100 mL) were fortified with the herbicides terbuthylazine and pendimethalin
(100 μg active ingredient each) and equilibrated for 14 hours. After DOM-flocculation with Cu (addition of 0,5 mM CuCl2) herbicide recovery was determined in the supernatant solutions and in the precipitate of Humic Cambisol-DOM, respectively.
Recovery of the herbicides from pure water was 85–99% and was not influenced by the addition of Cu. At low pH (4,8–5,3) DOM-flocculation
of different DOM-extracts was insufficient and varied in a range of 18 – 90%. Herbicide recovery from DOM-solutions decreased
moderately for terbuthylazine (60–90%) and strongly for pendimethalin (5 – 30%). In general, the addition of Cu caused no
further reduction of herbicide recovery from supernatant solutions, except for Humic Cambisol-DOM. The effects of Cu-addition
were most evident for pendimethalin (strongly reduced concentration in the supernatant solutions) and were considered to be
caused by a flocculation of DOM-bound moieties. Flocculation of Humic Cambisol-DOM increased from 18 – 24% at pH 5 to > 95%
at pH 8. However, at this pH the formation of Cu(OH)2 as a sorbing subcomponent of the flocculated matter lead to an overestimation of DOM-bound pendimethalin. Calculating this
side effect 6% of pendimethalin added was DOM-bound. Only traces of terbuthylazine (< 1%) were found in the solid matter of
flocculated Humic Cambisol-DOM.
To sum up, the new approach to separate freely dissolved herbicides from DOM-bound moieties not fully corresponded to our
expectations. DOM-flocculation was found to depend strongly on pH-environment influencing not only DOM-herbicide interactions
but also the clear separation of DOM-bound herbicides from herbicides in solutions. 相似文献
104.
Pankaj Kumar Vandana Mishra Saiyami Bhardwaj Shafali Garg Ludovic F. Dumée Radhey Shyam Sharma 《环境质量管理》2023,32(4):9-17
Sectorial approach for monitoring heavy metal pollution in rivers has failed to report realistic pollution status and associated ecological and human health risks. The increasing spread of heavy metals from different sources and emerging risks to human and environmental health call for reexamining heavy metal pollution monitoring frameworks. Also, the sources, spread, and load of heavy metals in the environment have changed significantly over time, requiring consequent modification in the monitoring frameworks. Therefore, studies on heavy metal monitoring in rivers conducted in the last decade were evaluated for experimental designs, research frameworks, and data presentations. Most studies (∼99%) (i) lacked inclusiveness of all environmental compartments; (ii) focused on “one pollutant – one/two compartment” or sometimes “one pollutant – one compartment – one effect” approach; and (iii) remained “data-rich but information poor.” An ecological approach with integrative system thinking is proposed to develop a holistic approach for monitoring river pollution. It is visualized that heavy metal monitoring, risk analyses, and water management must incorporate tracking pollutants in different environmental compartments of a river (water, sediment, and floodplain/bank soil) and consider correlating it with riverbank land use. The systems-based pollution monitoring and assessment studies will reveal the critical factors that drive heavy metals pollutant movement in ecosystems and associated potential risks to the environment, wildlife, and humans. Also, water quality and pollution indexing tools would help better communicate complex pollution data and associated risks among all stakeholders. Therefore, integrating systems approaches in scientific- and policy-based tools would help sustainably manage the health of rivers, wildlife, and humans. 相似文献
105.
Natasha Stoudmann Lena M. Reibelt Aime G. Rakotomalala Olivier Randriamanjakahasina Claude A. Garcia Patrick O. Waeber 《Natural resources forum》2021,45(1):87-102
A growing number of people are entering the artisanal and small‐scale mining (ASM) sector worldwide. In Madagascar, millions of individuals depend on this informal activity. Through a case study in the Alaotra‐Mangoro region of Madagascar, our research aimed to understand the “bottom‐up” dynamics and ripple effects of the sector, by looking at the realities for rural communities where inhabitants are both directly and indirectly affected by ASM. We were interested in community members' and miners' perceptions of the socio‐economic and environmental impacts of ASM, and in identifying the factors attracting people living in one of the country's agricultural hubs to this activity. Our results show a wide diversity of push and pull factors leading people to enter the sector. Although many positive impacts of ASM exist for miners and communities within the vicinity of mines, most miner participants considered themselves worse off since starting to mine, highlighting the high risk and low probability of return of ASM. ASM's potential for local and national development will remain squandered if its negative impacts continue to go unmanaged. Accounting for local contexts and the ripple effects of ASM will be crucial in achieving safety and security for miners, and to tap into the benefits it may offer communities while minimising environmental damage. 相似文献
106.
107.
Eleni?MatechouEmail authorView authors OrcID profile
return OK on get Geoff?K.?Nicholls Byron?J.?T.?Morgan Jaime?A.?Collazo James?E.?Lyons 《Environmental and Ecological Statistics》2016,23(4):531-547
We propose the use of finite mixtures of continuous distributions in modelling the process by which new individuals, that arrive in groups, become part of a wildlife population. We demonstrate this approach using a data set of migrating semipalmated sandpipers (Calidris pussila) for which we extend existing stopover models to allow for individuals to have different behaviour in terms of their stopover duration at the site. We demonstrate the use of reversible jump MCMC methods to derive posterior distributions for the model parameters and the models, simultaneously. The algorithm moves between models with different numbers of arrival groups as well as between models with different numbers of behavioural groups. The approach is shown to provide new ecological insights about the stopover behaviour of semipalmated sandpipers but is generally applicable to any population in which animals arrive in groups and potentially exhibit heterogeneity in terms of one or more other processes. 相似文献
108.
Dóra B. Huszár Rasmus S. Larsen Sarah Carlsen Jacobus J. Boomsma Jes Søe Pedersen 《Behavioral ecology and sociobiology》2014,68(11):1859-1870
Ant supercolonies (large networks of interconnected nests) represent the most extreme form of multi-queen breeding (polygyny) and have been found across ant lineages, usually in specific long-term stable populations. Many studies on the genetic population structure and demography of ant supercolonies have been done in recent decades, but they have lacked multicolonial control patches with separated colonies headed by a single or few queens so the origin of the supercolonial trait syndrome has remained enigmatic. Here, we set out to compare sympatric supercolonial and multicolonial patches in two natural Danish populations of the common red ant Myrmica rubra. We used DNA microsatellites to reconstruct genetic colony/population structure and obtained morphological and density measurements to estimate life history and ecology covariates. We found that supercolonies in both populations completely dominated their patches whereas colonies in multicolonial patches coexisted with other ant species. Supercolony patches had very low genetic differentiation between nests, negligible relatedness within nests, and lower inbreeding than multicolonial patches, but there were no significant morphological differences. One population also had nests that approached true outbred monogyny with larger workers and males but smaller queens than in the two other social nest types. Our results suggest that once smaller colonies start to adopt additional queens, they also gain the potential to ultimately become supercolonial when the habitat allows rapid expansion through nest budding. This is relevant for understanding obligate polygyny in ants and for appreciating how and why introduced North American populations of M. rubra have recently become invasive. 相似文献
109.
Baki Hazer Bahattin M. Baysal Ay?e G. K?seo?lu Necati Be?irli Elif Ta?k?n 《Journal of Polymers and the Environment》2012,20(2):477-484
The synthesis of polylactide (PLA)-b-poly (dimethyl siloxane) (PDMS) linear block copolymers and their use in blends with pure-PLA are described. PLA-b-PDMS linear block copolymers were obtained by the transesterification reaction in chloroform solution between poly(dimethyl siloxane) bis (2-aminopropyl ether) (molecular weight 2,000?Da) with PLA in the presence of stannous octoate. Molecular weights (Mw) of the block copolymers were varied from 53,800 to 63,600?Da while that of pristine PLA was 73,600?Da. The copolymers obtained were purified by fractional precipitation and then characterized by 1H NMR, FTIR, GPC, viscometry and DSC techniques. Blends of pure PLA with PLA-b-PDMS block copolymers displayed improved elastic properties (elongation up to 140%) compared to pure PLA (elongation ~9%). Thermal, mechanical and morphological characterization of the blends were also conducted. 相似文献
110.
We compared the natal dispersal behaviour of two mice species under laboratory conditions. Natal dispersal is a movement of an animal from its birthplace to its breeding area. This behaviour is known to be influenced by the mating system. In polygamous species, males are more likely to disperse, while in most of the monogamous species, both sexes disperse. Our subjects, the house mouse (Mus musculus) and the mound-building mouse (Mus spicilegus) are two sympatric species of the genus Mus. Both are native in Hungary, but they differ in their habitat type mating system and overwintering strategy. The house mouse is a polygynous species and adapted to human environment, known for mature and reproduce early. On the contrary, the mound-building mice are monogamous, and they inhabit extensively used agricultural fields, where they spend the unfavourable winter period in nest chambers under mounds, which they construct from soil and plant material. Successful overwintering for this species demands delayed maturity and reduced dispersion during the winter. Our results showed that the natal dispersal of these two species differ; both sexes of the mound-building mice dispersed later than the house mice, where a difference between sexes also occurs; house mice males dispersed earlier than females. The mound-building mice showed no sexual dimorphism in this behaviour. 相似文献