Protective effect of different types of bicycle helmets

The effectiveness of bicycle helmets in preventing head injuries is well documented. There are different opinions about the effectiveness of helmets in preventing face injuries, and few studies have analyzed the effect of different types of helmets. This study was performed to examine the effect of different helmet types to head and face injuries. The use of helmets was analyzed in cyclists with head or face injuries and compared with two control groups. The main control group was cyclists that had injuries not including the head or neck, and another control group was cyclists that had been involved in an accident, regardless of whether they had sustained any injury. Cross-table and logistic regression analyses were applied to analyze the protective effect of helmets. A total of 991 injured patients served as a basis for this study. Most of the accidents, (82%) were single accidents with no other persons involved. Of patients with injuries to the head, excluding face, 11.4% had been using hard shell helmets, and 9.6% had been using foam helmets at the time of the accident. Among the emergency room controls, the proportion of hard shell helmet users and foam helmet users was 26.4% and 11.4%, respectively. Compared to non-helmet users, this gave an odds ratio of 0.36 (CI = 0.21-0.60) for getting head injuries if the cyclists had been using hard shell helmets at the time of the injury, and 0.83 (CI = 0.41-1.67) for users of foam helmets. The odds ratio for getting face injuries was 0.90 (CI = 0.58-1.41) among users of hard shell helmets, and 1.87 (CI = 1.03-3.40) for users of foam helmets. The use of hard shell helmets reduced the risk of getting injuries to the head. Children less than nine years old that used foam helmets had an increased risk of getting face injuries. All bicyclists should be recommended to use hard shell bicycle helmets while cycling.     

Assessment of spatial variation of cesium-137 in small catchments

Surface contamination by bomb-derived and Chernobyl-derived 137Cs has been subject to changes due to physical decay and lateral transport of contaminated soil particles, which have resulted in an on-going transfer of radionuclides from terrestrial ecosystems to surface water, river bed sediments, and flood plains. Knowledge of the different sources of spatial variation of 137Cs is particularly essential for estimating 137Cs transfer to fluvial systems and for successfully applying 137Cs as an environmental tracer in soil erosion studies. This study combined a straightforward sediment redistribution model and geostatistical interpolation of point samples of 137Cs activities in soil to distinguish the effects of sediment erosion and deposition from other sources of variation in 137Cs in the small Mochovce catchment in Slovakia. These other sources of variation could then be interpreted. Besides erosion and deposition processes, the initial pattern of 137Cs deposition, floodplain sedimentation, and short-range spatial variation were identified as the major sources of spatial variation of the 137Cs inventory.     

Odor concentration decay and stability in gas sampling bags

This paper presents results of an experimental study into factors contributing to decay of odor samples during storage, between 4 and 40 hr after sample collection. The odor studied was sampled from a tobacco processing plant as part of collaborative research with a view to establishing a manual outlining methods for odor annoyance management, specifically for the tobacco industry. In August and September 1997, an experimental program was carried out in which two types of tobacco odor were sampled: Burley Toaster and Mix. The dependent variable was odor concentration in the bag, measured by dynamic olfactometry in accordance with the draft Comité Européen de Normalisation (CEN) standard EN13725 "Air Quality-Determination of Odor Concentration by Dynamic Olfactometry." The independent variables were sampling bag material, degree of dilution during sampling, dilution gas used, particle removal during sampling, and age of sample in hours. In the first phase, 94 odor analyses were carried out. In a second test, 32 samples were analyzed for odor concentration. In addition, 16 samples were analyzed using gas chromatography-mass spectrometry (GC-MS). Analysis of the results (analysis of variance) led to the unexpected conclusion that Nalophan film bags performed significantly better than metalized Cali-Bond layered film as a bag material. The odor concentration of samples in Nalophan bags remained relatively stable between 4 and 12 hr after sampling. After 30 hr, decay to about half the initial concentration, as measured at 4 hr, was observed. Particle removal during sampling caused the odor concentration in the bags to be reduced by approximately 20%. For practical reasons, particle removal remains useful, to avoid contamination of equipment. Using air or nitrogen as the neutral gas for pre-dilution during sampling or the dilution factor used (between factor 2 and 6) did not appear to have an effect on the decay characteristic of odor samples. The following recommendations are suggested for the practice of collecting odor samples and apply specifically to tobacco processing emissions: Analyze samples as soon as possible, preferably within 12 hr; When samples age for more than 12 hr, decay is likely to cause a reduction in odor concentration to half the original concentration at age 30 hr; Use sampling bags made of Nalophan NA or benchmark performance of other materials against Nalophan NA before using alternative materials; Use pre-dilution when sampling only for the purpose of avoiding condensation during sample storage. Use an appropriate minimum dilution factor to avoid condensation; Both nitrogen and high-purity (synthetic) air are suitable to use as neutral gas for pre-dilution; and When sampling tobacco odors, use an odorless filter to remove particles. This practice removes a source of variation and avoids contamination of equipment. The effect on results, despite being consistently lower in odor concentration, is not meaningful in terms of perceived intensity or annoyance potential.     

Tillage, intercrop, and controlled drainage-subirrigation influence atrazine, metribuzin, and metolachlor loss

Atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] have been found with increasing occurrence in rivers and streams. Their continued use will require changes in agricultural practices. We compared water quality from four crop-tillage treatments: (i) conventional moldboard plow (MB), (ii) MB with ryegrass (Lolium multiflorum Lam.) intercrop (IC), (iii) soil saver (SS), and (iv) SS + IC; and two drainage control treatments, drained (D) and controlled drainage-subirrigation (CDS). Atrazine (1.1 kg a.i. ha-1), metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazine-5(4H)-one] (0.5 kg a.i. ha-1), and metolachlor (1.68 kg a.i. ha-1) were applied preemergence in a band over seeded corn (Zea mays L.) rows. Herbicide concentration and losses were monitored from 1992 to spring 1995. Annual herbicide losses ranged from < 0.3 to 2.7% of application. Crop-tillage treatment influenced herbicide loss in 1992 but not in 1993 or 1994, whereas CDS affected partitioning of losses in most years. In 1992, SS + IC reduced herbicide loss in tile drains and surface runoff by 46 to 49% compared with MB. The intercrop reduced surface runoff, which reduced herbicide transport. Controlled drainage-subirrigation increased herbicide loss in surface runoff but decreased loss through tile drainage so that total herbicide loss did not differ between drainage treatments. Desethyl atrazine [6-chloro-N-(1-methylethyl)-1,3,5-triazine-2,4-diamine] comprised 7 to 39% of the total triazine loss.     

A quantitative evaluation of monitoring networks for region-specific nitrate reduction policies

Modern environmental policy implementation in many developed countries is increasingly regionally oriented. Regional governments have undertaken measures designed for the specific needs of the region but, so far, the resulting change in environmental quality has hardly been monitored. This study develops a method for the quantitative evaluation of region-specific environmental policy. Two forms of monitoring are distinguished: monitoring of performance of policy measures and monitoring of environmental quality. This study investigates two regions in the Netherlands where region-specific policy has been implemented. Performance monitoring focused on reduction of nitrate leaching to groundwater. Leaching reductions were calculated with simple models or rules of thumb. Quality monitoring focused on nitrate concentrations under grassland and other land use. An analysis of variance showed significant differences between different soil units. Stratified kriging was applied for spatial interpolation, showing within-unit variability. The current monitoring network could be improved by using a more regular type of grid.     

ESF Workshop

Dioxin and PCB monitoring programs for food and feeding stuff in most countries of the world, including many European Countries are currently inadequate. Better control of food production lines and food processing procedures is needed to minimize entry of dioxin to the food chain and will help to avoid dioxin contamination accidents. This would also improve the ability to trace back a possible contamination to its source. European guidelines for monitoring programs should be established to ensure comparable and meaningful results. These guidelines should define the minimum requirements for the design of monitoring programs, analytical methods, and quality assurance. Though data from Northern Europe shows that the general population exposure to dioxin and PCB has decreased during the last ten years these compounds continue to be a risk of accidental contamination of the food chain. The most prominent recent example is the Belgian dioxin contamination of feeding stuff in 1999. The Belgian dioxin contamination was not detected due to dioxin monitoring programs but by their direct biological effects seen in animals. Four other cases of dioxin contamination have been detected in Europe since 1997 due to local monitoring programs. One of them (citrus pulp pellets 1998) was in a much larger scale than the Belgian dioxin contamination. The general population's exposure to dioxins and PCBs is still in the same range (1-4 pg WHO-TEQ/kg body weight and day) as the recently revised WHO tolerable daily intake (TDI). There is concern that short-term high level exposure to dioxins, furans, and PCB may cause biological effects on the human fetal development and further research is required. Further actions to control sources building on considerable advances already made in many countries may need to be supplemented by measures to prevent direct contamination of feeding stuff or food to reduce general population exposure further.     

Application of a purge and trap TDS-GC/MS procedure for the determination of emissions from flame retarded polymers

Emissions of volatile organic compounds (VOCs) from different thermoplastic polymers used in electrotechnical applications were investigated using a purge and trap procedure that involved adsorption on Tenax GR. Results were compared to those for an operating TV set monitored in a test chamber. The analyses were in both cases carried out using thermodesorption gas chromatography with mass spectrometric detection (TDS-GC/MS). Substances identified were monomers, volatile additives, or related compounds. Special attention was given to the detection of halogenated compounds. Their origin was studied using reference samples and synthetic standards.     

Monitoring, modelling and environmental exposure assessment of industrial chemicals in the aquatic environment

Monitoring and laboratory data play integral roles alongside fate and exposure models in comprehensive risk assessments. The principle in the European Union Technical Guidance Documents for risk assessment is that measured data may take precedence over model results but only after they are judged to be of adequate reliability and to be representative of the particular environmental compartments to which they are applied. In practice, laboratory and field data are used to provide parameters for the models, while monitoring data are used to validate the models' predictions. Thus, comprehensive risk assessments require the integration of laboratory and monitoring data with the model predictions. However, this interplay is often overlooked. Discrepancies between the results of models and monitoring should be investigated in terms of the representativeness of both. Certainly, in the context of the EU risk assessment of existing chemicals, the specific requirements for monitoring data have not been adequately addressed. The resources required for environmental monitoring, both in terms of manpower and equipment, can be very significant. The design of monitoring programmes to optimise the use of resources and the use of models as a cost-effective alternative are increasing in importance. Generic considerations and criteria for the design of new monitoring programmes to generate representative quality data for the aquatic compartment are outlined and the criteria for the use of existing data are discussed. In particular, there is a need to improve the accessibility to data sets, to standardise the data sets, to promote communication and harmonisation of programmes and to incorporate the flexibility to change monitoring protocols to amend the chemicals under investigation in line with changing needs and priorities.