A single chorionic gonadotropin assay for maternal serum screening for Down's syndrome

A simple enzyme immunoassay measuring human chorionic gonadotropin in undiluted maternal serum has been developed in order to be used as a prenatal screening test for Down' s syndrome. A retrospective study of maternal serum sampled during pregnancies associated with trisomy 21 shows that with a 5% amniocentesis rate determined on a single test, the detection rate of trisomy 21 would be around two-thirds of the affected pregnancies. A prospective study of 9040 pregnant women under 38 years has confirmed the usefulness of the assay.     

Air quality monitoring for multiple pollutants: Optimization of a network around a hypothetical potash plant and two thermal power stations in open countryside

A method is presented for the design of multi-pollutant air quality monitoring networks (AQMN). This technique leads to an optimal network, i.e. a network providing a maximum of information with a minimum of measurement devices. The spatial correlation analysis technique is used to compare the information given by the potential sites that may form the network. The concept of potential of violation is defined to take into account the number of times that the maximum emission values tolerated by law are exceeded. Both objectives are weighted automatically through an adjustable parameter, b, for which an estimation procedure has been developed in this study, depending on the purpose of the network. Several methods are described, allowing simultaneous consideration of different pollutants. As an illustration of these methods, a number of air quality monitoring networks is designed to perform an analysis of the environmental impact due to a hypothetical potash processing plant and two thermal power stations.     

1,2-Dichlorobenzene Marine Risk Assessment with Special Reference to the Osparcom Region: North Sea

This risk assessment on 1,2-dichlorobenzene was carried out for the marine environment, following methodology given in the EU risk assessment Regulation (1488/94) and Guidance Document of the EU New and Existing Substances Regulation (TGD, 1996). Data from analytical monitoring programmes in large rivers and estuaries in the North Sea area were collected and evaluated on effects and environmental concentrations. Risk is indicated by the ratio of predicted environmental concentration (PEC) to predicted no-effect concentration (PNEC) for the marine aquatic environment. In total, 26 data for fish, 24 data for invertebrates and 17 data for algae were evaluated. Acute and chronic toxicity studies were taken into account and appropriate assessment factors used to define a final PNEC value of 37 microg/l. All available monitoring data indicate that 1,2-dichlorobenzene levels in estuaries are below 0.1 microg/l. Worst case concentrations in rivers are below 0.45 microg/l. With this value, calculated PEC/PNEC ratios give safety margins of 100 to 300, taking no account of dilution in the sea. 1,2-dichlorobenzene is not a 'toxic, persistent and liable to bioaccumulate' substance sensu the Oslo and Paris Convention for the Prevention of Marine Pollution (OSPAR-DYNAMEC) criteria. Environmental fate and effects data indicate that current use of 1,2-dichlorobenzene poses no risk to the aquatic environment.     

Effects of ozone fumigation treatment on the removal of residual difenoconazole from strawberries and on their quality

The effect of ozone fumigation on the reduction of difenoconazole residue on strawberries was studied. Strawberries were immersed in 1.0 L of aqueous solution containing 400 μL of the commercial product (250 g L^?1 of difenoconazole) for 1 min. Then, they were dried and exposed to ozone gas (O₃) at concentrations of 0.3, 0.6 and 0.8 mg L^?1 for 1 h. The ozone fumigation treatments reduced the difenoconazole residue on strawberries to concentrations below 0.5 mg kg^?1, which corresponds to a 95% reduction. The strawberries treated with ozone and the control group, which was not treated with ozone, were stored at 4°C for 10 days. Some characteristics of the fruit were monitored throughout this period. Among these, pH, weight loss and total color difference did not change significantly (P > 0.05). The fumigation with ozone significantly affected the soluble solids, titratable acidity and ascorbic acid content (vitamin C) of the strawberries preventing a sharp reduction of these parameters during storage.     

Toxicological aspects of trihalomethanes: a systematic review

Environmental Science and Pollution Research - Chlorine is considered the most used chemical agent for water disinfection worldwide. However, water chlorination can lead to by-product generation...     

Stress-related gene expression changes in rainbow trout hepatocytes exposed to various municipal wastewater treatment influents and effluents

The present study sought to examine the performance of six different wastewater treatment processes from 12 wastewater treatment plants using a toxicogenomic approach in rainbow trout hepatocytes. Freshly prepared rainbow trout hepatocytes were exposed to increasing concentrations of influent (untreated wastewaters) and effluent (C₁₈) extracts for 48 h at 15 °C. A test battery of eight genes was selected to track changes in xenobiotic biotransformation, estrogenicity, heavy metal detoxification, and oxidative stress. The wastewaters were processed by six different treatment systems: facultative and aerated lagoons, activated sludge, biological aerated filter, biological nutrient removal, chemically assisted primary treated, and trickling filter/solids contact. Based on the chemical characteristics of the effluents, the treatment plants were generally effective in removing total suspended solids and chemical oxygen demand, but less so for ammonia and alkalinity. The 12 influents differed markedly with each other, which makes the comparison among treatment processes difficult. For the influents, both population size and flow rate influenced the increase in the following mRNA levels in exposed hepatocytes: metallothionein (MT), cytochrome P4503A4 (CYP3A4), and vitellogenin (VTG). Gene expression of glutathione S-transferase (GST) and the estrogen receptor (ER), were influenced only by population size in exposed cells to the influent extracts. The remaining genes—superoxide dismutase (SOD) and multidrug resistance transporter (MDR)—were not influenced by either population size or flow rate in exposed cells. It is noteworthy that the changes in MT, ER, and VTG in cells exposed to the effluents were significantly affected by the influents across the 12 cities examined. However, SOD, CYP1A1, CYP3A4, GST, and MDR gene expression were the least influenced by the incoming influents. The data also suggest that wastewater treatments involving biological or aeration processes had the best performance. We found that the effects of municipal effluents on gene expression depended on the population size, the initial properties of the incoming influent, and the wastewater treatment method applied. Considering that the long-term goals of wastewater treatment is to produce clean effluents for the aquatic biota and independent of the incoming influent, more research is needed in developing treatment processes to better protect aquatic life from anthropogenic contamination.     

Larval growth and settlement of the European oyster (Ostrea edulis) as a function of food quality measured as fatty acid composition

Larval growth rate and settlement of the European flat oyster Ostrea edulis were experimentally studied as a function of the composition of dietary fatty acids. Diets differing in fatty acid composition were composed by mixtures of the microalgae Isochrysis galbana, Pavlova lutheri and Chaetoceros calcitrans. Fatty acid content in the tissue of the feeding larvae, analyzed by gas chromatography and mass spectrometry, reflected the composition in the diet. Larval growth rate was significantly correlated to the three omega-3 polyunsaturated fatty acids (PUFA) C18:3, C18:4 and C22:6, with minor differences for neutral and polar lipids. No relation between growth rate and the omega-3 PUFA C20:5 was detected, a PUFA often implied as essential for bivalves. It is suggested that naturally occurring variability in fatty acid composition may constrain larval growth. In settlement experiments in both still water and flume flow little substrate selectivity was found for some contrasting substrates. It is concluded that differences in dietary fatty acids may explain as much of settlement success as the variability of substrates. Received: 12 October 1998 / Accepted: 6 April 1999