Polychlorinated biphenyls and links to cardiovascular disease

The pathology of cardiovascular disease is multi-faceted, with links to many modifiable and non-modifiable risk factors. Epidemiological evidence now implicates exposure to persistent organic pollutants, such as polychlorinated biphenyls (PCBs), with an increased risk of developing diabetes, hypertension, and obesity; all of which are clinically relevant to the onset and progression of cardiovascular disease. PCBs exert their cardiovascular toxicity either directly or indirectly via multiple mechanisms, which are highly dependent on the type and concentration of PCBs present. However, many PCBs may modulate cellular signaling pathways leading to common detrimental outcomes including induction of chronic oxidative stress, inflammation, and endocrine disruption. With the abundance of potential toxic pollutants increasing globally, it is critical to identify sensible means of decreasing associated disease risks. Emerging evidence now implicates a protective role of lifestyle modifications such as increased exercise and/or nutritional modulation via anti-inflammatory foods, which may help to decrease the vascular toxicity of PCBs. This review will outline the current state of knowledge linking coplanar and non-coplanar PCBs to cardiovascular disease and describe the possible molecular mechanism of this association.     

Characterization of municipal solid waste combustion in a grate furnace

The objective of this paper is to evaluate the combustion process of municipal solid waste combustion in a grate furnace both experimentally and numerically by using data of a reference experiment with over-stoichiometric primary air supply. Measurements were carried out inside the combustion chamber of a pilot plant by monitoring temperatures and sampling gaseous combustion products along the bed surface. The data were assessed using elemental and energy balances. Experimental data of the axial temperature profiles of the flue gas, the fuel bed and the grate bars, as well as local gas flows and the flue gas composition measured above the fuel bed along the grate were used to describe the conversion process, including drying and carbon burnout. These data served as input to model the thermo- and fluid dynamic processes of the gas phase above the bed inside the combustion chamber. For this purpose the commercial code FLUENT was employed to carry out the simulations. Thus, the turbulent temperature, flow and species distributions in the combustion chamber of the pilot waste incinerator TAMARA were predicted. The results of the FLUENT modeling showed that under the prevailing conditions the flue gas burnout is almost completed before entering the first flue due to high temperatures, effective mixing and sufficient residence times of the flue gas inside the combustion chamber. This agrees well with the experimental results inside the first flue. On the basis of the above mentioned results, design and parametric studies can be carried out in a more efficient way by saving cost and time.     

On the use of manned hydrogen-gas ballooning in boundary layer studies

Measurements of nitrogen dioxide, ozone and, for the first time, on-line, nonmethane hydrocarbons with a quasicontinuous gaschromatographic/flame ionization technique were performed on a manned hydrogen-gas balloon platform. A cycle time of 10 min allowed the determination of nonmethane hydrocarbons in the carbon number range of C₄-C₁₀ with a detection limit of 10 pptv. In addition, meteorological parameters (atmospheric pressure, temperature, humidity) along with GPS-data (global positioning system) was accomplished during the balloon flights. Balloon measurements of trace compounds provide valuable information about photochemical processes in the boundary layer since gas ballooning offers the only technique that stays in the same air parcel along Langrangian trajectories. In addition, gas ballooning represents a unique tool to elucidate micrometeorological observations such as atmospheric stability oscillations and local wind fields.     

An object-oriented software for fate and exposure assessments

The model system CemoS¹ (Chemical Exposure Model System) was developed for the exposure prediction of hazardous chemicals released to the environment. Eight different models were implemented involving chemicals fate simulation in air, water, soil and plants after continuous or single emissions from point and diffuse sources. Scenario studies are supported by a substance and an environmental data base. All input data are checked on their plausibility. Substance and environmental process estimation functions facilitate generic model calculations. CemoS is implemented in a modular structure using object-oriented programming. e-mail: cemos@aphrodite.mathematik.uni-osnabrueck.de     

Influence of pore size of plankton nets and towing speed on the sampling performance of two high-speed samplers (Delfino I and II) and its consequences for the assessment of plankton populations

The sampling performance of two high-speed samplers, (Delfino I and II), fitted with a calibrated flow meter, was studied in the open Ligurian Sea using a battery comprising 6 such Delfinos linked together. Since, in plankton counts, only those organisms should be counted which are definitely retained in the nets, several techniques for the separation of the organisms which pass through the pore of a net of a given pore size and those which are safely retained were tested. Attempts to separate these two fractions by filtration of the fixed sample through nets of different pore sizes were not successful, as living organisms were able to pass through pore sizes which retained dead organisms. However, optical sizing under the dissecting microscope during counting gave reproducible results. Using this counting technique, the influence of the pore size of plankton nets on the reproducibility of sampling of natural populations was studied. The results obtained show that live plankton passes through the net pores at a size at which fixed plankton is retained. Hence, the minimum retention size for living and dead plankton is different. By comparing samples taken with nets of different pore sizes, and counting the organisms caught according to different sizes, it was possible to determine the minimum retention size of live plankton organisms for several different net pore-sizes. The minimum retention size is, therefore, the smallest pore size at which the organisms of a certain width cannot escape through the pores of the net and are, thus, quantitatively retained in the net. By applying the criterion of minimum retention size, the influence of speed towing on the number of plankton organisms caught was studied. It was shown that the number of organisms which are safely retained, i.e., do not escape through the pores, increased with speed, reaching a plateau at 5 to 7 knots.A contribution under the Association Contract CNEN-EURATOM. Contribution No. 668 of the Euratom Biology Division.     

Terrestrische ökotoxikologische Testmethoden für die Tropen

Goal, Scope, and Background

Soil organisms play a crucial role in the terrestrial ecosystem. Plant Protection Products (PPPs) are known to affect soil organisms and might have negative impacts on soil functions influenced by these organisms. Little research has been done to day on the impact of PPs on tropical ecosystems. Therefore, in this study it was investigated whether fate and effects of pesticides differ between tropical and temperate regions and whether data generated under temperate conditions can be used for the Environmental Risk Assessment (ERA) in tropical regions.

Methods

In the first part of this study, the effects of two fungicides (Benomyl and Carbendazim) and one insecticide (lambda-Cyhalothrin) on soil invertebrates (i.e. earthworms and arthropods) were evaluated in laboratory tests modified for tropical conditions (temperature, soil, test species). Besides using some native species, the tests were done mainly with two (temperate and tropical) strains of earthworms (Eisenia fetida) and the peregrine isopod speciesPorcellionides pruinosus as standard test species. The chemicals were spiked in two natural and two artificial soils. A tropical artificial soil (TAS), containing a tropical fern product (Xaxim) or coconut coir dust as organic matter, was developed in this study.

Results and Conclusions

The results from the laboratory tests showed that all three test chemicals differed from those gained under temperate conditions. In the case of the fungicides the toxicity was lower but in the case of the insecticide higher under tropical than under temperate conditions. The native tropical earthwormPontoscolex corethrurus reacted more sensitively against Carbendazim in comparison to the standard test speciesEisenia fetida.

Recommendation and Perspective

Details of the environmental risk assessment of the three model chemicals based on the results of the laboratory described here (and including the results of higher tier tests (semi-field and field tests)) will be described in Part 2 of this series