Brazil's Electric Power Choices and Their Corresponding Carbon Emissions Implications

This study analyzes the options for meeting power demand in the Brazilianpower sector through the year 2015. Three policy cases are constructedto test economic and environmental policy measures against a baseline:advanced technologies scenario, environmental control scenario and carbon(C) elimination scenario. Least-cost modeling simulated these scenarios throughchanges in emissions fees and caps, costs for advanced technologies,demand side efficiency, and clean energy supplies. Results show that, in theabsence of alternative policies, new additions to Brazil's electric powersector will shift rapidly from hydroelectricity to combined-cycle natural gasplants. When the cost of environmental impacts are incorporated in theprice of power, the least-cost mix of electric power generation technologycould change in other ways. In all scenarios, energy efficiency andcogeneration play an important role in the least-cost power solution. Savingelectricity through increased efficiency offsets the needs for new supply andhas enormous potential in Brazil's industrial sector. Efficiency also reducesthe environmental burden associated with electricity production andtransmission, without compromising the quality of the services demandedby end users. Interesting enough, carbon dioxide (CO₂) emissions will remainrelatively low under almost every conceivable scenario.     

First trimester prenatal diagnosis of haemophilia A: Two years' experience

We evaluated the feasibility, reliability, and acceptability of prenatal diagnosis of haemophilia A by DNA analysis of chorionic villi. Twenty-two women at risk to transmit the abnormal gene were referred for prenatal diagnosis, two of them twice. Two of the 22 women appeared to be non-carriers by DNA analysis. In one of these women, the results were known only after chorionic villus sampling had been carried out. Thirteen of the twenty carriers were heterozygous for an intragenic (Bell or Xbal) marker; six women were only heterozygous for the extragenic DXS52 (Stl4) locus. One of the women was homozygous for all the presently known DNA markers within or closely linked with the factor VIII locus. Twelve of the 22 fetuses at risk were male, ten were female. Seven of the 12 male fetuses were shown to be affected and were subsequently aborted. Four male fetuses appeared to be not affected. In one case, the diagnosis was made by use of an extragenic marker. The woman rejected fetal blood sampling to confirm the diagnosis. After birth, a normal factor VIII level was found in three of the four cases. The fourth pregnancy is still continuing. In one of the 12 male fetuses, no diagnosis at the gene level was possible. DNA analysis is expected to provide maximum certainty as to the phenotype of the fetus for approximately 60 per cent of the women; for another 37 per cent a rate of misdiagnosis of 4–5 per cent applies. In only 3 per cent of the cases will no diagnosis at the gene level be possible as yet. The new possibility of a prenatal diagnosis in the first trimester of pregnancy enabled some of these women to have a family of their own and was appreciated in particular by the women who underwent fetoscopy in an earlier pregnancy.     

Early maps as stepping stones for the reconstruction of historic ecological conditions and biota

We reconstructed the flora of a European region at a historical point in time from historical topographical maps that contain rather precise information about the condition and composition of habitats. The ecological information obtained from these maps can be enriched through the potential of broadly diversified archival information. This study is confined to grassland communities. Considerations in terms of phytosociology make historical lists of plant species a good starting point for the reconstruction of grassland communities. The combination of historical and scientific methods proves suitable for reconstructing specific historical environmental conditions. Taking into account the frequency of relevant historical sources in European archives as well as in archives abroad, this approach claims for far-reaching application to ecosystem restoration matters, especially if ecological information from natural sources is missing.     

The use of XAD-resins for the detection of mutagenic activity in water: I. Studies with surface water

A study of the effects of different XAD-resins, bed volume, flow rate, pH and type of eluent on the extraction of organic mutagens from surface water is presented. XAD-4/8 is as effective as XAD-2 in concentrating organic mutagens from surface water and dimethylsulfoxide (DMSO) is as efficient as acetone in eluting the adsorbed organic mutagens. The latter allows direct testing up to 0.5 ml of DMSO concentrate in the Ames test. Variation of the pH of the water after passing the XAD-4/8, followed by readsorption, shows that the majority of the mutagenic activity due to dissolved organics is adsorbed at neutral pH. Only a minor fraction is readsorbed at pH 3. Further a XAD-4/8 concentrate and a similar concentrate prepared by freeze drying gives similar mutagenic activity. This indicates that many of the organic mutagens are recovered in the XAD-4/8 concentrate.It is concluded that adsorption on XAD-4/8, followed by direct testing of the DMSO eluates in the Ames test, presents a rapid and relatively simple way to detect low concentrations of organic mutagens in surface water. The general suitability of the method is shown for different types of surface water.     

Irrigation runoff insecticide pollution of rivers in the Imperial Valley, California (USA)

The Alamo and New Rivers located in the Imperial Valley, California receive large volumes of irrigation runoff and discharge into the ecologically sensitive Salton Sea. Between 1993 and 2002 we conducted a series of studies to assess water quality using three aquatic species: a cladoceran (Ceriodaphnia dubia), a mysid (Neomysis mercedis), and a larval fish (Pimephales promelas). Although no mortality was observed with the P. promelas, high-level toxicity to the invertebrate species was documented in samples from both rivers during many months of each year. Toxicity identifications and chemical analyses identified the organophosphorus insecticides (OP), chlorpyrifos and diazinon, as the cause of C. dubia toxicity. The extent of the C. dubia mortality was highly correlated with quantities of these OPs applied in the river watersheds. C. dubia mortality occurred during more months of our 2001/2002 study than in the 1990s investigations. During 2001/2002, the extensive C. dubia mortality observed in New River samples was caused by OP insecticide pollution that originated from Mexico. Mortality to N. mercedis in New River samples was likely caused by contaminants other than OP insecticides. Our studies document OP insecticide-caused pollution of the Alamo River over a 10-year period and provide the necessary information for remediation efforts.     

Significance of platinum group metals emitted from automobile exhaust gas converters for the biosphere

Intention, Goal, Scope, Background  Following the introduction of automobile catalytic converters the platinum group metals (PGM) platinum (Pt), palladium (Pd) and rhodium (Rh) gain on increasing interest in environmental research as these metals are emitted with exhaust fumes into the environment. Consequently, elevated PGM levels were found in different environmental matrices uch as road dusts, soils along heavily frequented roads, sediments of urban rivers etc. Accordingly, the effects of increasing PGM emissions on the biosphere are controversially discussed. Objective  This paper summarizes the present knowledge on the biological availability of PGM to plants and animals. As biological availability is one of the most decisive factors determining the toxicologi-cal potential of xenobiotics, this information is very important to evaluate the possible threat of the noble metals to ecosystems. Results and Discussion  The availability of soluble as well as particle bound PGM to terrestrial plants was demonstrated in several studies. Experimental investigations revealed uptake of Pt, Pd and Rh also by aquatic plants. Additionally, the biological availability of the noble metals for animals has been verified in experimental studies using soluble metal salts, catalytic converter model substances, sediments of urban rivers, road dust or tunnel dust as metal sources. These studies refer mainly to aquatic animals. Beside of free living organisms, in particular worms parasitizing fish demonstrated a high potential to accumulate PGM. This could be of great interest in respect of biomonitoring purposes. Generally, for plants as well as for animals Pd turns out to be the best available metal among the PGM. Compared to other heavy metals, the biological availability of PGM from road dust to zebra mussels(Dreissena polymorpha) ranged between that of Cd and Pb. Conclusion  Especially chronic effects of PGM on the biosphere can not be excluded due to (1) their cumulative increase in the environment, (2) their unexpected high biological availability and bioaccumulation and (3) their unknown toxicological and ecotoxicological potential. However, it appears that acute effects on ecosystems due to anthropogenic PGM emission are not likely. Recommendation and Outlook  Research on environmental PGM contamination of the biosphere, especially the fauna, and on long-term toxiciry of low PGM concentrations is highly appreciated. These studies require very sensitive analytical techniques to determine PGM even in low sample amounts. Research has to be done in particular on reliable determination of (ultra) trace levels of Pd and Rh as the lack of data on these two metals is mainly due to analytical problems.     

Contaminated sediments and bioassay responses of three macroinvertebrates, the midge larva Chironomus riparius, the water louse Asellus aquaticus and the mayfly nymph Ephoron virgo

Bioassays are widely used to estimate ecological risks of contaminated sediments. We compared the results of three whole sediment bioassays, using the midge larva Chironomus riparius, the water louse Asellus aquaticus, and the mayfly nymph Ephoron virgo. We used sediments from sixteen locations in the Dutch Rhine-Meuse Delta that differed in level of contamination. Previously developed protocols for each bioassay were followed, which differed in sediment pretreatment, replication, and food availability. The Chironomus bioassay was conducted in situ, whereas the other two were conducted in the laboratory. The measured endpoints, survival and growth, were related to contaminant levels in the sediment and to food quantity in water and sediment.

Only the response of A. aquaticus in the bioassay was correlated with sediment contamination. Food availability in overlying water was much more important for C. riparius and E. virgo, thereby masking potential sediment contaminant effects. We conclude that growth of A. aquaticus was depressed by sediment contamination, whereas growth of E. virgo and C. riparius was stimulated by seston food quantity. We discuss that the trophic state of the ecosystem largely affects the ecological risks of contaminated sediments.     

Monitoring of polychlorinated biphenyls in Belgian human adipose tissue samples

Polychlorinated biphenyls (PCBs) were monitored in Belgian human adipose tissue samples from deceased individuals (n=100). Their mean age was 52, ranging from 2 to 91 years. There were 57 men and 43 women. Other known variables were date of autopsy and place of residence. No information about diet or occupation was available. The seven marker congeners PCB 28, 52, 101, 118, 138, 153 and 180 were analysed in the samples with a GC-MS/MS method validated according to Commission Decision 2002/657/EC. Extracted fat was cleaned-up over a glass column filled with n-hexane, acid silica, deactivated alumina and anhydrous sodium sulfate. The whole procedure was subjected to a rigorous quality control programme with retention times, ion chromatograms and intensity ratios of the monitored product ions as identification criteria. The total PCB concentration ranged between 10 and 1640 ng g-1 fat, with a mean value of 658 ng g-1 fat. In the age groups of 0-9 (n=1), 10-19 (n=4), 20-29 (n=11), 30-39 (n=13), 40-49 (n=15), 50-59 (n=14), 60-69 (n=14), 70-79 (n=20), 80-89 (n=6) and 90-99 (n=2), the mean total PCB concentrations were 10, 134, 253, 445, 557, 687, 807, 962, 959, and 1191 ng g-1 fat, respectively. So, there was an increase of PCB body burden with age. For the male subjects (n=57; mean age of 53) the mean total PCB concentration was 633 ng g-1 fat. For the female subjects (n=43; mean age of 52) it was 690 ng g-1 fat. There was no significant sex-related difference in the concentrations of marker PCBs.     

Using thermal units for estimating critical period of weed competition in off-season maize crop

Brazilian off-season maize production is characterized by low yield due to several factors, such as climate variability and inadequate management practices, specifically weed management. Thus, the goal of this study was to determinate the critical period of weed competition in off-season maize (Zea mays L.) crop using thermal units or growing degree days (GDD) approach to characterize crop growth and development. The study was carried out in experimental area of the University of S?o Paulo, Brazil, with weed control (C), as well as seven coexistence periods, 2, 4, 6, 8, and 12 leaves, flowering, and all crop cycle; fourteen treatments were done. Climate data were obtained from a weather station located close to the experimental area. To determine the critical period for weed control (CPWC) logistic models were fitted to yield data obtained in both W and C, as a function of GDD. For an arbitrary maximum yield loss fixed in 2.5%, the CPWC was found between 301 and 484 GDD (7-8 leaves). Also, when the arbitrary loss yield was fixed in 5 and 10%, the period before interference (PBI) was higher than the critical weed-free period (CWFP), suggesting that the weeds control can be done with only one application, between 144 and 410 GDD and 131 and 444 GDD (3-8 leaves), respectively. The GDD approach to characterize crop growth and development was successfully used to determine the critical period of weeds control in maize sown off-season. Further works will be necessary to better characterize the interaction and complexity of maize sown off-season with weeds. However, these results are encouraging because the possibility of the results to be extrapolated and because the potential of the method on providing important results to researchers, specifically crop modelers.