Do racial differences exist in second-trimester maternal hCG levels? a study of 23 369 patients

In Down syndrome screening by maternal serum human chorionic gonadotropin (hCG) determination at 15, 16, 17, and 18 weeks of gestation, we prospectively examined 23 369 sera from white (21 549), North African (970), black African (525), and Asian (325) patients. When expressed as multiples of the median (MOM), no difference was observed between white, North African, and black African patients. However, higher serum hCG concentrations were noted in Asians, for whom we therefore recommend correction of hCG values before calculation of the risk of Down syndrome.     

Herbicides and nitrogen in precipitation: progression from west to east and contribution to the Marne river (France)

Herbicides and nitrogen fallout were studied in France at six sites from west to east. Atrazine, a herbicide widely used in France and forbidden in some European countries was found. Its fallout was quantified to 400 kg on the river Marne catchment (13 500 km2), an agricultural region located east of Paris. The average fallout contribution to the Marne river contamination was estimated at 20 ng/l from March to August. Independently of the wind direction, only a small part of this atmospheric contamination can reach adjacent countries.     

Biodegradability of wheat gluten based bioplastics

A large variety of wheat gluten based bioplastics, which were plasticized with glycerol, were subjected to biodegradation. The materials covered the total range available for the biochemical control parameter Fi, which expresses the percentage of aggregated proteins. This quantity can be related to the density of covalent crosslinks in the wheat gluten network, which are induced by technological treatments. The biodegradability tests were performed in liquid medium (modified Sturm test) and in farmland soil. All gluten materials were fully degraded after 36 days in aerobic fermentation and within 50 days in farmland soil. No significant differences were observed between the samples. The mineralization half-life time of 3.8 days in the modified Sturm test situated gluten materials among fast degrading polymers. The tests of microbial inhibition experiments revealed no toxic effects of the modified gluten or of its metabolites. Thus, the protein bulk of wheat gluten materials is non-toxic and fully biodegradable, whatever the technological process applied.     

How accurately do semi-permeable membrane devices measure the bioavailability of polycyclic aromatic hydrocarbons to Daphnia magna?

Semi-permeable membrane devices (SPMDs) are passive samplers that have been designed to sample the bioavailable fractions of hydrophobic organic compounds in aquatic ecosystems. This study aims at evaluating the ability for SPMD to sample polycyclic aromatic hydrocarbons (fluoranthene, pyrene and benzo[a]pyrene) that are actually bioavailable to Daphnia magna. For that purpose, the SPMD-available fraction and the bioavailable fraction to D. magna are compared in controlled media with Dissolved Organic Matters (DOMs) from various origins and at different concentrations. The presence of all but one DOM reduces the accumulation of PAHs in SPMD or in D. magna. Moreover, this comparative laboratory study shows that in 10 cases on 13, the SPMD-available fraction is close to the available fraction to D. magna. When significant differences are observed between SPMD-available and bioavailable fractions, they remain less than 50% at DOM concentrations below 10 mg/l DOC, which corresponds to a maximum DOC concentration usually found in temperate rivers. This study confirms the suitability of the SPMD technique to monitor readily bioavailable hydrophobic contaminants in aquatic environments containing DOM from various origins and characteristics.     

Use of treated bark for the removal of lipids from water

Raw, biologically treated bark and bark impregnated with transition metal ions were used to retain the lipids from synthetic emulsions. Several experimental parameters affecting the lipid removal efficiency (RE) were studied (initial concentration of lipids, temperature, time, pH, carboxylic acid chain length, etc.). Saturated bark was characterized using Fourier transform infrared (FTIR) spectroscopy and light microscopy, and the treated bark wetting index was determined. Results show that lipid removal can exceed 95% of the initial concentration at a pH lower than 7. The uptake of lipids by these sorbents varied from 0.2 to 2.5 g/g of dry bark. Trials for regenerating the sorbent saturated by lipids allowed the recovery of approximately 95% of lipids. The calorific value of the saturated bark was approximately 79% that of domestic fuel and can be considered as an energy source, thus avoiding its waste disposal. These results may upgrade the treatment of wastewater generated by several industrial sectors, such as the food industry, surface treatment, and so on.     

Catalytic NO(chi) reduction with simultaneous dioxin and furan oxidation

The engineering, construction, performance and running costs of a catalytic flue gas cleaning component in the low dust area of a municipal waste incinerator is discussed. For this purpose, the case study of a Flemish incineration plant is presented, covering the history, the design procedure of the catalyst, relevant process data and the financial aspects. A reliable PCDD/F-destruction by means of oxidation by the catalyst to typical values of 0.001 ng TEQ/Nm3 has been demonstrated. At the same time, NO(chi)- and CO-emissions are reduced by 90% and 20% to about 50 mg/N m3 andbelow 10 mg/N m3, respectively.     

Note on the variability of heterotrophic activity measurements by the 14C method in sea water

Twenty five measurements in triplicate of heterotrophic activity in sea water showed good reproducibility. The mean coefficient of variation was 6.2%, which is lower than the coefficient of variation obtained with a similar method for primary production measurements. This result indirectly confirms that most heterotrophic activity can be attributed to a great number of small cells, i.e., bacteria which, if not free-swimming, are fixed to particles of smaller size than the average phytoplankton. The good reproducibility obtained also suggests that there was no extraneous contamination despite non-sterile working conditions.     

Effect of ambient oxygen concentration on activities of enzymatic antioxidant defences and aerobic metabolism in the hydrothermal vent worm, Paralvinella grasslei

The alvinellid Paralvinella grasslei is a common endemic polychaete from the deep-sea hydrothermal vent communities located on the East Pacific Rise (EPR). These organisms colonise a large range of microhabitats around active sites where physico-chemical conditions are thought to generate reactive oxygen species (ROS). Furthermore, in this aerobic organism, ROS could also be generated by the activity of the mitochondrial respiratory chain. In this paper, we investigated the effect of ambient oxygen concentration on the activities of three essential antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX) and their relationships with the activity of enzymes involved in aerobic metabolism (cytochrome c oxidase, COX; citrate synthase, CS). Results of incubation of P. grasslei in a high-pressure vessel with circulating seawater at different oxygen partial pressures indicate that this worm regulates COX and CS activities differently in gills and body wall. CAT and GPX activities increase in these tissues when animals are maintained in filtered surface seawater. Moreover, levels of malondialdehyde increase in gills, testifying that oxidative damage occurs under these conditions. CAT and GPX activities are positively related to COX and CS activities, but no correlation was detected between SOD and the metabolic enzyme activities. In comparison with littoral annelids, SOD activities are very high whereas CAT activities are very low or absent in P. grasslei. The possible reasons for the occurrence of such differences are discussed.     

Monitoring concentrations of persistent organic pollutants in the general population: the international experience

Assessing the adverse effects on human health of persistent organic pollutants (POPs) and the impact of policies aiming to reduce human exposure to POPs warrants monitoring body concentrations of POPs in representative samples of subjects. While numerous ad hoc studies are being conducted to understand POPs effects, only a few countries are conducting nationwide surveillance programs of human concentrations of POPs, and even less countries do so in representative samples of the general population. We tried to identify all studies worldwide that analyzed the distribution of concentrations of POPs in a representative sample of the general population, and we synthesized the studies' main characteristics, as design, population, and chemicals analyzed. The most comprehensive studies are the National Reports on Human Exposure to Environmental Chemicals (USA), the German Environmental Survey, and the Arctic Monitoring and Assessment Programme. Population-wide studies exist as well in New Zealand, Australia, Japan, Flanders (Belgium) and the Canary Islands (Spain). Most such studies are linked with health surveys, which is a highly-relevant additional strength. Only the German and Flemish studies analyzed POPs by educational level, while studies in the USA offer results by ethnic group. The full distribution of POPs concentrations is unknown in many countries. Knowledge gaps include also the interplay of age, gender, period and cohort effects on the prevalence of exposures observed by cross-sectional surveys. Local and global efforts to minimize POPs contamination, like the Stockholm convention, warrant nationwide monitoring of concentrations of POPs in representative samples of the general population. Results of this review show how such studies may be developed and used.     

Polycyclic aromatic hydrocarbons storage by Fusarium solani in intracellular lipid vesicles

Accumulation and elimination of polycyclic aromatic hydrocarbons (PAHs) were studied in the fungus Fusarium solani. When the fungus was grown on a synthetic medium containing benzo[a]pyrene, hyphae of F. solani contained numerous lipid vesicles which could be stained by the lipid-specific dyes: Sudan III and Rhodamine B. The fluorescence produced by Rhodamine B and PAH benzo[a]pyrene were at the same locations in the fungal hyphae, indicating that F. solani stored PAH in pre-existing lipid vesicles. A passive temperature-independent process is involved in the benzo[a]pyrene uptake and storage. Sodium azide, a cytochrome c oxidation inhibitor, and the two cytoskeleton inhibitors colchicine and cytochalasin did not prevent the transport and accumulation of PAH in lipid vesicles of F. solani hyphae. F. solani degraded a large range of PAHs at different rates. PAH intracellular storage in lipid vesicles was not necessarily accompanied by degradation and was common to numerous other fungi.