Influences of perfluorooctanoic acid on the aggregation of multi-walled carbon nanotubes

The aggregation of multi-walled carbon nanotubes (MWCNTs) in the aqueous phase not only inhibits their extensive utilization in various aspects but also dominates their environmental fate and transport.The role of surfactants at low concentration in the aggregation of MWCNTs has been studied,however the effect of perfluorinated surfactants at low concentration is uncertain.To understand this interfacial phenomenon,the influences of perfluorooctanoic acid (PFOA),and sodium dodecyl sulfate (SDS) as a control,on MWCNT aggregation in the aqueous phase were examined by the UV absorbency method.Influences of pH and cationic species on the critical coagulation concentration (CCC) value were evaluated.The CCC values were dependent on the concentration of PFOA,however a pronounced effect of SDS concentration on the CCC values was not observed.The CCC values of the MWCNTs were 51.6 mmol/L in NaCl and 0.28 mmol/L in CaCl 2 solutions,which suggested pronounced differences in the effects of Na+ and Ca2+ ions on the aggregation of the MWCNTs.The presence of both PFOA and SDS significantly decreased the CCC values of the MWCNTs in NaCl solution.The aggregation of the MWCNTs took place under acidic conditions and was not notably altered under neutral and alkaline conditions due to the electrostatic repulsion of deprotonated functional groups on the surface of the MWCNTs.     

Body mass estimations for <Emphasis Type="Italic">Plateosaurus engelhardti</Emphasis> using laser scanning and 3D reconstruction methods

Both body mass and surface area are factors determining the essence of any living organism. This should also hold true for an extinct organism such as a dinosaur. The present report discusses the use of a new 3D laser scanner method to establish body masses and surface areas of an Asian elephant (Zoological Museum of Copenhagen, Denmark) and of Plateosaurus engelhardti, a prosauropod from the Upper Triassic, exhibited at the Paleontological Museum in Tübingen (Germany). This method was used to study the effect that slight changes in body shape had on body mass for P. engelhardti. It was established that body volumes varied between 0.79 m³ (slim version) and 1.14 m³ (robust version), resulting in a presumable body mass of 630 and 912 kg, respectively. The total body surface areas ranged between 8.8 and 10.2 m², of which, in both reconstructions of P. engelhardti, ∼33% account for the thorax area alone. The main difference between the two models is in the tail and hind limb reconstruction. The tail of the slim version has a surface area of 1.98 m², whereas that of the robust version has a surface area of 2.73 m². The body volumes calculated for the slim version were as follows: head 0.006 m³, neck 0.016 m³, fore limbs 0.020 m³, hind limbs 0.08 m³, thoracic cavity 0.533 m³, and tail 0.136 m³. For the robust model, the following volumes were established: 0.01 m³ head, neck 0.026 m³, fore limbs 0.025 m³, hind limbs 0.18 m³, thoracic cavity 0.616 m³, and finally, tail 0.28 m³. Based on these body volumes, scaling equations were used to assess the size that the organs of this extinct dinosaur have.     

Natural and man-made organobromine compounds in marine biota from Central Norway

Brominated organic pollutants were found in selected samples of mollusk tissue, fish liver, as well as in the eggs and livers of shag from three sites in Central Norway. More than 80 organobromines were identified owing to the defined isotope ratio acquired by GC/ECNI-MS. However, only a few peaks could be assigned to anthropogenic brominated flame retardants (polybrominated diphenyl ethers). Most of the organobromine compounds detected were unknown or halogenated natural products. The known halogenated natural products MHC-1 and TBA were abundant in all samples and usually between equally abundant, and up to 50 fold more concentrated than the major polybrominated diphenyl ether congener BDE 47. The halogenated natural products BC-2 (2-MeO-BDE 68) and BC-3 (6'-MeO-BDE 47), were on level with BDE 100 which was the second most abundant BDE congener in many samples. The previously identified natural polybrominated hexahydroxanthene derivatives (PBHDs) were detected for the first time in bird eggs. Being major contaminants in bird eggs, PBHDs were only present at low levels in bird liver from nestlings originating from the same clutch. Such differences were detected for several other major contaminants. One unknown tetrabromo compound particularly abundant in mussels from Munkholmen was studied by GC/MS and the molecular ion was detected at m/z 446. The abundance of the most important unknown compounds did not correlate with BDEs and they most likely represent halogenated natural products. This study supports that halogenated natural products have to be treated as serious contaminants of marine coastal waters. Our data suggest that their abundance is highest in habitats along the shoreline. Thorough examination of these compounds in environmental samples is an important task.     

Impact of climate change: an empirical investigation of Malaysian rice production

This paper examines the possible impact of climate change on Malaysian rice production. Using the Ricardian Method and farm household data, we have examined the effects on rice producers focusing on sharecropper adaptations and ecological causes. The principle goal of this research paper is to investigate the impact of climate variables such as temperature, rainfall and precipitation on rice production during main and off seasons, in Kedah, Malaysia. The main purpose of this paper is to examine how climate change affects the net income of paddy farmers in the study area. The statistically significant results show that temperature, rainfall, farm size, educational knowledge, land area and value of labour input have an impact on rice production per hectare revealing potential impacts of climate vulnerability on Malaysian agriculture. The results showed that net revenue increased by Ringgit Malaysia (RM 1= $0.3277) 4.78 per hectare throughout the main seasons as a result of minimal increase in the temperature while there is a decrease of RM 3.02 in the net revenue per hectare during off seasons. During the off season, rainfall increased revenue per hectare by RM 1.32 and during the main season it reduced revenue per hectare by RM 1.01. The evidence from this study may be useful for Malaysian policymakers to facilitate greater preventive measures during the main and off-seasons to counteract climate uncertainty and vulnerability.     

Nutritionally relevant elements in staple foods: influence of arable site versus choice of variety

Eighteen representative sites for the Austrian grain-growing and eight for the potato-growing zones (soils and crops) were investigated. On each site, total element contents (B, Ba, Ca, Cd, Co, Cu, Fe, K, Li, Mg, Mn, Mo, Na, P, Sr and Zn) were determined in 4–12 varieties of winter wheat (n = 136), 6 varieties of spring durum wheat (n = 30), 5 varieties of winter durum wheat (n = 15), 7 varieties of rye (n = 49), 5 varieties of spring barley (n = 30) and 5 varieties of potatoes (n = 40). Element accumulations in grain species and potato tubers varied significantly with site conditions, with the main exceptions for B in potatoes and wheat as well as for Zn, Cu and Co in durum wheat. On average, across all investigated sites, differences in varieties occurred concerning the elements Ca, Cd, Ba, Sr and Zn (except Zn in potatoes and winter durum). A rough estimation revealed that an average Austrian consumer of wheat, rye and potatoes meets more than 50% of the needs of daily element intake for K, P and Mg, between 36 and 72% for Fe, Zn and Cu, and more than 100% for Co, Mo and Mn. In particular, the elements Ca and Na have to be added from other sources.     

long Term Goals for Environmental Control— What’s Desirable and Possible in the Year 2000?

A panel discussion looking forward to the environment in the year 2000, was arranged by Lionel V. Baldwin, Program Chairman for APCA’s 67th Annual Meeting. To provide a lofty introduction of the subject he reached into outer space for a moderator—Captain Walter M. Schirra, one of the original astronaut team.     

Mesoscale Air Pollution Transport in the Chicago Lake Breeze

A two-day field program in Chicago studied mesoscale pollution transport during typical lake breezes. Streamlines calculated from serial pibal data suggest that a nearly closed circulation cell traps pollutants emitted near a shore line. Optically tracked tetroons confirm the helical trajectory of air within the lake breeze regime. Pollutants released within the inflow layer move inland, rise in a narrow zone of updrafts (100 cm/sec) at the lake breeze front, advect lakeward in the return flow layer aloft, and then subside back down into the inflow layer. Pollution then fumigates back to the surface as the air returns inland a second time causing concentrations higher than would otherwise be expected. Spectral aerosol measurements (0.5-3.0 and 7.0-9.0 micrometer size ranges) made by an instrumented aircraft reveal a marked particle size sorting.     

Distribution,fate and formation of non-extractable residues of a nonylphenol isomer in soil with special emphasis on soil derived organo-clay complexes

Anthropogenic contaminants like nonylphenols (NP) are added to soil, for instance if sewage-sludge is used as fertilizer in agriculture. A commercial mixture of NP consists of more than 20 isomers. For our study, we used one of the predominate isomers of NP mixtures, 4-(3,5-dimethylhept-3-yl)phenol, as a representative compound. The aim was to investigate the fate and distribution of the isomer within soil and soil derived organo-clay complexes. Therefore, ¹⁴C- and ¹³C-labeled NP was added to soil samples and incubated up to 180 days. Mineralization was measured and soil samples were fractionated into sand, silt and clay; the clay fraction was further separated in humic acids, fulvic acids and humin. The organo-clay complexes pre-incubated for 90 or 180 days were re-incubated with fresh soil for 180 days, to study the potential of re-mobilization of incorporated residues. The predominate incorporation sites of the nonylphenol isomer in soil were the organo-clay complexes. After 180 days of incubation, 22 % of the applied ¹⁴C was mineralized. The bioavailable, water extractable portion was low (9 % of applied ¹⁴C) and remained constant during the entire incubation period, which could be explained by an incorporation/release equilibrium. Separation of organo-clay complexes, after extraction with solvents to release weakly incorporated, bioaccessible portions, showed that non-extractable residues (NER) were preferentially located in the humic acid fraction, which was regarded as an effect of the chemical composition of this fraction. Generally, 27 % of applied ¹⁴C was incorporated into organo-clay complexes as NER, whereas 9 % of applied ¹⁴C was bioaccessible after 180 days of incubation. The re-mobilization experiments showed on the one hand, a decrease of the bioavailability of the nonylphenol residues due to stronger incorporation, when the pre-incubation period was increased from 90 to 180 days. On the other hand, a shift of these residues from the clay fraction to other soil fractions was observed, implying a dynamic behavior of incorporated residues, which may result in bioaccessibility of the NER of nonylphenol.     

Biomonitoring of heavy metals in the feathers of House crow (Corvus splendens) from some metropolitans of Asia and Africa

Environmental Science and Pollution Research - Urban-dwelling birds can be useful biomonitors to assess the impact of the urbanisation on both public and wildlife health. Widely distributed urban...