Assessment of sampling and chemical analysis of source-separated organic household waste

The quality of the waste sampling procedure and chemical analysis was evaluated in a research program on characterization of organic waste obtained after disc screening of source-separated organic household waste. The sampling procedures focused on a truckload of waste and involved several steps of subsampling including shredding, mixing, blending, high-speed-blending, drying and milling prior to analysis of the organic waste with respect to ash content, crude fibers, crude fat, crude protein, sugar, starch, enzyme-digestible organic matter, P, N, C, H, S and calorific value. The statistical evaluation of the procedures involved 10 samples of the same truckload of waste obtained by splitting the sample at each level in the procedure according to a staggered, incomplete nested statistical design. Furthermore, one sample was analysed six times over a period of approximately one year. The statistical evaluation showed that no single step in the sampling procedure contributed with excessive variance and that the variance caused by the sampling procedure was approximately the same as the variance in the chemical analysis observed over a year. The variance varied with the analytical parameter but for most parameters the uncertainty was satisfactorily low (of the order of 3-10% expressed as the relative standard deviation, which is considered to be satisfactory for waste characterization).     

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.     

From the editors

Editorial Introduction

From the editors     

Vitellogenin induction in Cyprinus carpio treated with 17beta-estradiol and 4-nonylphenol

The aim of the present study was to demonstrate induction ofvitellogenin in the common carp (Cyprinus carpio) as abiomarker for monitoring freshwater ecosystems. Sexually undifferentiated specimens of common carp were treated experimentally with 17-estradiol and increasing doses of 4-nonylphenol and levels of plasma Vtg were measured in orderto: 1) validate an ELISA assay for plasma Vtg in the common carpusing the polyclonal rabbit anti-salmon Vtg antibody AA1 (Biosense, Norway); 2) check the sensitivity of carp juvenilesin producing Vtg in response to estrogen stimulation. The grouptreated with 17-estradiol showed high induction (156%)with respect to controls, also groups treated with 4-nonylphenolshowed induction of Vtg. The group treated with 100 mg kg^-1b.wt showed an induction of 61%. A statistically significantcorrelation was found between dose and response. This preliminary study demonstrate a response to the ELISA assay for Vtg in the common carp using rabbit anti-salmon antibody AA1. With further evidence the tested biomarker might be proposed for large scale monitoring of estrogenic effects caused by pollution in urban and industrial effluents.     

Transport and degradation of toluene and o-xylene in an unsaturated soil with dipping sedimentary layers

A lysimeter trench was established at the Gardermoen delta (50 km north of Oslo, Norway) to study the flow of water and transport and degradation of aromatic jet fuel components (toluene and o-xylene) in the undisturbed unsaturated zone. Site investigations with ground-penetrating radar revealed the presence of dipping sedimentary layers within the foreset unit. This study has shown that the foreset bed of the Gardermoen delta structure provided a preferential flow path for the transport of the solute plumes, but did not have dramatic effects on the degradation potential under the current conditions. The degradation potential for toluene and o-xylene in the unsaturated zone at Gardermoen was very high and almost all of the injected hydrocarbons were biodegraded before reaching the saturated zone. However, the horizontal displacement of the plume showed that knowledge about sedimentary structures in the unsaturated zone is important for a sufficient monitoring of contaminant transport and for remediation purposes. Carbon dioxide and O2 were measured in situ simultaneously with extraction of water samples, and indicated aerobic biodegradation of toluene and o-xylene. Overall, first-order degradation coefficients were calculated to be in the range of 0.19 to 0.21 d(-1) and 0.10 to 0.11 d(-1) for toluene and o-xylene, respectively.     

Sorption of polycyclic aromatic compounds to humic and fulvic acid HPLC column materials

Two different humic acids (HA) and a fulvic acid (FA) were chemically immobilized to a high performance liquid chromatography (HPLC) silica column material. The immobilization was performed by binding amino groups in HA/FA to the free aldehyde group in glutardialdehyde attached to the silica gel. The HPLC column materials were compared with a blank column material made by applying the same procedure but without immobilizing HA or FA. Also, a column was made by binding carbonyl groups in HA to amino groups attached to the silica gel. The humic substances were selected to secure appropriate variation of their structural features. The retention factors of 45 polycyclic aromatic compounds (PAC) to the four columns were determined by HPLC. The advantage of the technique is a large number of compounds can easily be studied. The binding procedure does not appear to cause a drastic selection between the HA molecules. The k' values obtained for the two Aldrich HA columns agree in general reasonably. The retention or sorption of the compounds increased with the size of the PAC and the number of lipophilic substituents, but decreased when polar substituents were present. The PAC retention was much stronger to the two HA columns than to the FA and blank column, both for hydrophobic polycyclic aromatic hydrocarbons (PAH) and the polar PAC. Other factors impacting the PAC binding may be specific interactions with HA and the ionic strength of the aqueous phase. The technique has been applied to do direct determinations of Koc.     

GRADUATE TRAINING IN WATER TRACK ENVIRONMENTAL ENGINEERING: RESULTS OF A SURVEY OF EMPLOYERS1

ABSTRACT: The authors conducted a mail survey of 600 employers in the government and private sectors who were thought to hire water track environmental engineers. Of a total of 148 respondents, over 80 percent employed a combined total of over 2,800 environmental engineers. The survey addressed two basic questions: (1) what is the quality of graduate education recently trained engineers have received, and (2) what effect does a nonengineering undergraduate degree have on an engineering graduate student's employment potential. In answer to the first question, respondents indicated that engineering graduates were deficient in report writing, business law (contracts and specifications), economics and finance, and practical design. Many employers stated that students could better prepare themselves for employment by (1) obtaining professional experience through internships and summer or part-time jobs, and (2) learning to communicate effectively, both orally and in writing. In answer to the second question, 50 percent of the respondents indicated that engineers without an engineering undergraduate degree would not necessarily be limited in their abilities to perform engineering duties.     

Review of ozone and temperature lidar validations performed within the framework of the Network for the Detection of Stratospheric Change

The use of assimilation tools for satellite validation requires true estimates of the accuracy of the reference data. Since its inception, the Network for Detection of Stratospheric Change (NDSC) has provided systematic lidar measurements of ozone and temperature at several places around the world that are well adapted for satellite validations. Regular exercises have been organised to ensure the data quality at each individual site. These exercises can be separated into three categories: large scale intercomparisons using multiple instruments, including a mobile lidar; using satellite observations as a geographic transfer standards to compare measurements at different sites; and comparative investigations of the analysis software. NDSC is a research network, so each system has its own history, design, and analysis, and has participated differently in validation campaigns. There are still some technological differences that may explain different accuracies. However, the comparison campaigns performed over the last decade have always proved to be very helpful in improving the measurements. To date, more efforts have been devoted to characterising ozone measurements than to temperature observations. The synthesis of the published works shows that the network can potentially be considered as homogeneous within +/-2% between 20-35 km for ozone and +/-1 K between 35-60 km for temperature. Outside this altitude range, larger biases are reported and more efforts are required. In the lower stratosphere, Raman channels seem to improve comparisons but such capabilities were not systematically compared. At the top of the profiles, more investigations on analysis methodologies are still probably needed. SAGE II and GOMOS appear to be excellent tools for future ozone lidar validations but need to be better coordinated and take more advantage of assimilation tools. Also, temperature validations face major difficulties caused by atmospheric tides and therefore require intercomparisons with the mobile systems, at all sites.