Background, Aim and Scope
In this paper recent results are provided of an investigation on the discovery of 12 perfluorinated surfactants (PS) in different
surface and drinking waters (Skutlarek et al. 2006 a, Skutlarek et al. 2006 b). In the last years, many studies have reported
ubiquitous distribution of this group of perfluorinated chemicals, especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic
acid (PFOA) in the environment, particularly in wildlife animal and human samples (Giesy and Kannan 2001, Houde et al. 2006,
Prevedouros et al. 2006). Perfluorinated surfactants (e.g. PFOS and PFOA) have shown different potentials for reproductory
interference and carcinogenity in animal experiments as well as partly long half-lives in humans (Guruge et al. 2006, FSA
UK 2006a, FSA UK 2006b, 3M 2005, OECD 2002, Yao and Zhong 2005). They possess compound-dependent extreme recalcitrance against
microbiological and chemical degradation and, in addition, they show variable potentials for bioaccumulation in animals and
humans (Houde et al. 2006).
Materials and Methods:
Surface and drinking water samples were collected from different sampling sites:
- Surface waters: samples taken from the rivers Rhine, Ruhr, Moehne and some of their tributaries. Further samples were taken
from the Rhine-Herne-Canal and the Wesel-Datteln-Canal.
- Drinking waters: samples taken in public buildings of the Rhine-Ruhr area.
After sample clean-up and concentration by solid-phase extraction, the perfluorinated surfactants were determined using HPLC-MS/MS.
Results:
All measured concentrations (sum of seven mainly detected components) in the Rhine river and its main tributaries (mouths)
were determined below 100 ng/L. The Ruhr river (tributary of the Rhine) showed the highest concentration (94 ng/L), but with
a completely different pattern of components (PFOA as major component), as compared with the other tributaries and the Rhine
river. Further investigations along the Ruhr river showed remarkably high concentrations of PS in the upper reaches of the
Ruhr river and the Moehne river (tributary of the Ruhr) (Ruhr: up to 446 ng/L, Moehne: up to 4385 ng/L). The maximum concentration
of all drinking water samples taken in the Rhine-Ruhr area was determined at 598 ng/L with the major component PFOA (519 ng/L).
Discussion:
The surface water contaminations most likely stem from contaminated inorganic and organic waste materials (so-called 'Abfallgemisch').
This waste material was legally applied to several agricultural areas on the upper reaches of the Moehne. Perfluorinated surfactants
could be detected in some suchlike soil samples. They contaminated the river and the reservoir belonging to it, likely by
superficial run-off over several months or probably years. Downstream, dilution effects are held responsible for decreasing
concentrations of PS in surface waters of the Moehne and the Ruhr river. In analogy to the surface water samples, PS (major
component PFOA) can be determined in many drinking water samples of the Rhine-Ruhr area where the water supplies are mainly
based on bank filtration and artificial recharge.
Conclusions:
The concentrations found in drinking waters decreased with the concentrations of the corresponding raw water samples along
the flow direction of the Ruhr river (from east to west) and were not significantly different from surface water concentrations.
This indicates that perfluorinated surfactants are at present not successfully removed by water treatment steps.
Recommendations and Perspectives:
Because of their different problematic properties (persistence, mobility, toxicity, bioaccumulation), the concentrations of
specific perfluorinated surfactants and their precursors in drinking waters and food have to be minimised. Therefore, it is
of utmost importance to take the initiative to establish suitable legal regulations (limitations/ban) concerning the production
and use of these surfactants and their precursors. Furthermore, it is indispensable to protect water resources from these
compounds. A discussion on appropriate limit values in drinking water and foodstuffs is urgently needed. Concerning the assumed
soil contamination, the corresponding regulation (Bioabfall-Verordnung 1998 – Regulation on Organic Waste 1998) should be
extended to allow the control of relevant organic pollutants. 相似文献
Different bacterial strains able to attack polyoxyethylene-type nonionic surfactants were isolated by enrichment procedure from the surface waters of the Arno River. Alkylphenol polyethoxylates and alkyl polyethoxylates, as well as polyethylene glycols, were degraded and assimilated by bacterial strains in axenic cultures. Degradative routes of polyethyleneoxide chains were investigated by matching each bacterial isolate with several types of nonionic surfactants and polyethers and by the identification of their degradation products isolated during aerobic digestion experiments. In accordance with previous reports, the first attack led to the shortening of the poly(oxyethylene) chains of the nonionic surfactants. It was found that the strains able to degrade PEG segments of nonionic surfactants possess enzymatic systems unable to degrade free PEGs, whereas those degrading the latter substrates cannot degrade PEG segments coupled to hydrophobic moieties. 相似文献
Membrane modification is one of the most feasible and effective solutions to membrane fouling problem which tenaciously hampers the further augmentation of membrane separation technology. Blending modification with nanoparticles (NPs), owing to the convenience of being incorporated in established membrane production lines, possesses an advantageous viability in practical applications. However, the existing blending strategy suffers from a low utilization efficiency due to NP encasement by membrane matrix. The current study proposed an improved blending modification approach with amphiphilic NPs (aNPs), which were prepared through silanization using 3-(Trimethoxysilyl)propyl methacrylate (TMSPMA) as coupling agents and ZnO or SiO2 as pristine NPs (pNPs), respectively. The Fourier transform infrared and X-ray photoelectron spectroscopy analyses revealed the presence of appropriate organic components in both the ZnO and SiO2 aNPs, which verified the success of the silanization process. As compared with the pristine and conventional pNP-blended membranes, both the ZnO aNP-blended and SiO2 aNP-blended membranes with proper silanization (100% and 200%w/w) achieved a significantly increased blending efficiency with more NPs scattering on the internal and external membrane surfaces under scanning electron microscope observation. This improvement contributed to the increase of membrane hydrophilicity. Nevertheless, an extra dosage of the TMSPMA led to an encasement of NPs, thereby adversely affecting the properties of the resultant membranes. On the basis of all the tests, 100% (w/w) was selected as the optimum TMSPMA dosage for blending modification for both the ZnO and SiO2 types.
Soil aggregation plays an important role in agricultural production activities. However, the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management, resulting in the loss of water, fertilizers and pesticides in soil. At present, hydrogels have been widely reported to promote the formation of soil aggregation. In this paper, amphiphilic calcium alginate (ASA/Ca2+) was applied to promote the formation of soil aggregation and enhance pesticide retention. Initially, an ASA was obtained through the one-pot Ugi condensation (a four-component green chemical reaction). Then, ASA/Ca2+ hydrogel is prepared by Ca2+ cross-linking. The formation of soil aggregation was determined through the Turbiscan Lab Expert stability analyzer, Confocal Laser Scanning Microscope (CLSM), and Transmission Electron Microscope (TEM). And the effect of soil aggregation on acetamiprid environmental behavior was investigated by adsorption kinetics, adsorption isotherms, and leaching. The results shown that the three-dimensional network structure of ASA/Ca2+ hydrogel can promote the formation of soil aggregation. Aggregate durability index (ADI) was 0.55 in the presence of ASA/Ca2+ hydrogel, indicating that amphiphilic hydrogel can enhance the stability of soil aggregation. The adsorbing capacity of acetamiprid was 1.58 times higher than pure soil, and the release of acetamiprid only about 20% in the presence of ASA/Ca2+ hydrogel. These results would be helpful for the formation of soil aggregation and pesticides adsorption on soil aggregation. Thus, ASA/Ca2+ hydrogel is likely to improve soil quality, simultaneously it can minimize the mobility of pesticides in the agricultural system. 相似文献