Determining the Chernobyl impact on sediments of a pre-Alpine lake with a very comprehensive set of data

Man-made and natural radionuclides in Lake Wallersee were determined in the pre-Alpine environment at the northern slope of the Alps, which was heavily affected by the Chernobyl fallout in May 1986. The objective of this study was to get knowledge of location and quantity of man-made radionuclide input (especially (137)Cs) generated in the Chernobyl accident to lake sediments. Eleven sediment cores were sampled and activity depth profiles of (137)Cs and (210)Pb were determined with 5mm depth-resolution. The Chernobyl fallout produced an extreme (137)Cs peak in the sediment cores providing an excellent time marker. The chronological interpretation of deeper sediment layers was done by radiochemical analysis of (90)Sr and (239+240)Pu, which were released during atmospheric weapons' tests in the 1950s and 1960s. This allowed a complete chronological analysis of the sediment cores with a very compact set of data.     

Size-fractionated thorium isotopes (228Th, 230Th, 232Th) in surface waters in the Jiulong River estuary, China

Thorium isotopes (228Th, 230Th, 232Th and 234Th) are useful tracers for studying particle dynamics and trace element scavenging in marine environments. In this study, surface waters were collected along a salinity gradient from the Jiulong River estuary, China, for determination of activity concentrations of 228Th, 230Th and 232Th in different size fractions, namely, the >53 microm, 10-53 microm, 2-10 microm, 0.4-2 microm, 10 kDa-0.4 microm and the <10 kDa fractions. Our results indicated that the activity concentrations of 228Th, 230Th and 232Th in the Jiulong River estuarine waters were significantly higher than most of the previously reported values in coastal and oceanic seawaters, suggesting a higher lithogenic U and Th contribution from the Jiulong River Basin. When normalized to the particulate mass concentration, the activity concentrations of the three thorium isotopes decreased with increasing particle size, demonstrating the important role of surface areas of particles in controlling the scavenging of thorium from the water column. The partitioning of three thorium isotopes showed a common characteristic, i.e., the >53 microm fraction had the least share (0-1%), while the 10-53 microm fraction had the largest share of Th isotopes. The average value of the 230Th/232Th activity ratio (230Th/232Th)(A.R.) increased from 0.8 in the >53 microm fraction to 3.7 in the 10 kDa-0.4 microm fraction, indicating that the radiogenic Th isotopes are preferentially scavenged by the small size particles. (230Th/232Th)(A.R.) in the <10 kDa and 10 kDa-0.4 microm fractions were similar, however, suggesting a similar chemical composition and/or equilibrium partitioning between the low molecular weight and colloidal Th. It was very interesting to note that the geochemical behaviors of the three Th isotopes were different from each other. Dissolved 228Th had the highest concentration in the mid-salinity region, showing a non-conservative behavior with additional input. In contrast, dissolved 232Th showed a concave profile, indicating a net removal of 232Th during the mixing of fresh water with seawater. The behavior of Th isotopes in the <10 kDa fraction followed those in the dissolved phases. The difference in geochemical behaviors among three Th isotopes was ascribed to their different sources in the estuary.     

Contamination of persistent organic pollutants (POPs) and relevant management in China

The status of typical persistent organic pollutant (POP) contamination in many media (e.g., farm produce, soil, human milk, water, and sediments) was surveyed and China's relevant countermeasures for controlling POPs were analyzed in this paper. The results showed that the proportion of organochlorine pesticides (OCPs) to all kinds of pesticides has descended significantly since 1983 when the OCPs were forbidden from being used. The spatial distribution characteristic of pesticide application in the whole country was as follows: southeast>central>northwest. The pesticide residues in food with high fat and high protein content were more than that in foodstuffs. The residual concentration in soil in the whole country was as follows: south>central>north. Furthermore, in vegetable fields, the residual concentration was higher than that in crop fields. As for human milk, the retained amount tended to decrease. In the recent two decades, although the reduction was 81.5%, it was still higher than that in some developed European and American countries. The rank of the residual concentrations of OCPs in different media was: human milk>animal foodstuff>soil>vegetable food>water and sediment. The initial relevant POP management in China can be traced back to 1982 when the Ordinance of Pesticide Management was enacted. Now, environmental control of POPs in China is close to the international level. The legal management system of POPs can be divided into four facets, including 3 regulations, 6 ordinances, and 20 standards. However, on the whole, most of the existing regulations do not refer to POPs directly. Only some clauses mention POPs and lack pertinent, explicit statements on POP pollution and control. Legislation is urgently needed for more effective environmental management to enhance POP control.     

The relation of non-culpable traffic incidents to bus drivers' celeration behavior

PROBLEM: The driver celeration behavior theory predicts that celerations are associated with incidents for which the driver has some responsibility in causing, but not other incidents. METHOD: The hypothesis was tested in 25 samples of repeated measurements of bus drivers' celeration behavior against their incidents for two years. RESULTS: The results confirmed the prediction; in 18 samples, the correlation for culpable incidents only was higher than for all incidents, despite the higher means of the latter. Non-culpable incidents had correlations close to zero with celeration. DISCUSSION: It was pointed out that most individual crash prediction studies have not made this differentiation, and thus probably yielded underestimates of the associations sought, although the effect is not strong, due to non-culpable accident involvements being few (less than a third of the total). The methods for correct identification of culpable incident involvements were discussed.     

Degradation of hop bitter acids by fungi

Nine fungal strains related to: Trametes versicolor, Nigrospora oryzae, Inonotus radiatus, Crumenulopsis sororia, Coryneum betulinum, Cryptosporiopsis radicicola, Fusarium equiseti, Rhodotorula glutinis and Candida parapsilosis were tested for their ability to degrade humulones and lupulones. The best results were obtained for T. versicolor culture, in which humulones and lupulones were fully degraded after 4days of incubation in the dark or after 36h in the light. The experiments were performed on a commercial hop extract and on sterilized spent hops.     

Combustion characteristics of simulated gas fuel in a 30 kg/h scale pyrolysis-melting incinerator

Combustion characteristics of gas fuel in a pyrolysis-melting incinerator having a 30kg/h capacity were investigated. Pyrolyzed gas from waste was simulated by propane that was injected in the combustion chamber, and burnt through multi-staged combustion by distributing the combustion air to primary, secondary, and tertiary air nozzles. Temperatures and the concentrations of gas components in the combustion chamber were measured. Combustion performance was evaluated with respect to the temperature distribution and combustion gas concentrations of O(2), CO and NO(x). Using secondary air and/or tertiary air, the combustion performance was improved, and, in particular, NO(x) concentration decreased significantly following the tertiary air injection.     

Ammonia assessment from agriculture: U.S. status and needs

Recent studies suggest that human activities accelerate the production of reactive nitrogen on a global scale. Increased nitrogen emissions may lead to environmental impacts including photochemical air pollution, reduced visibility, changes in biodiversity, and stratospheric ozone depletion. In the last 50 yr, emissions of ammonia (NH3), which is the most abundant form of reduced reactive nitrogen in the atmosphere, have significantly increased as a result of intensive agricultural management and greater livestock production in many developed countries. These agricultural production practices are increasingly subject to governmental regulations intended to protect air resources. It is therefore important that an accurate and robust agricultural emission factors database exist to provide valid scientific support of these regulations. This paper highlights some of the recent work that was presented at the 2006 Workshop on Agricultural Air Quality in Washington, D.C. regarding NH3 emissions estimates and emission factors from agricultural sources in the U.S. and Europe. In addition, several best management practices are explored as the scientific community attempts to maximize the beneficial use of reactive nitrogen while simultaneously minimizing negative environmental impacts.     

Utilization of washed MSWI fly ash as partial cement substitute with the addition of dithiocarbamic chelate

The management of the big amount of fly ash as hazardous waste from the municipal solid waste incinerator (MSWI) has encountered many problems in China. In this study, a feasibility research on MSWI fly ash utilization as partial cement substitute in cement mortars was therefore carried out. MSWI fly ash was subjected to washing process to reduce its chlorine content (from 10.16% to 1.28%). Consequently, it was used in cement mortars. Ten percent and 20% replacement of cement by washed ash showed acceptable strength properties. In TCLP and 180-day monolithic tests, the mortars with washed ash presented a little stronger heavy metal leachability, but this fell to the blank level (mortar without washed ash) with the addition of 0.25% chelate. Therefore, this method is proposed as an environment-friendly technology to achieve a satisfactory solution for MSWI fly ash management.