The impact of global change on economic values of water for Public Irrigation Schemes at the São Francisco River Basin in Brazil

Economic values of water for the main Public Irrigation Schemes in the sub-middle region of the São Francisco River Basin, in northeastern Brazil, are determined in this study using an integration of a global agro-economic land and water use (MAgPIE) with a local economic model (Positive Mathematical Programming). As in the latter, the water values depend on the crops grown, and as Brazilian agriculture is strongly influenced by the global market, we used a regionalized version of the global model adapted to the region in order to simulate the crop land use, which is in turn determined by changes in global demand, trade barriers, and climate. The allocation of sugarcane and fruit crops projected with climate change by the global model, showed an impact on the average yields and on the water costs in the main schemes resulting in changes in the water values locally. The economic values for all schemes in the baseline year were higher than the water prices established for agricultural use in the basin. In the future, these water values will be higher in all the schemes. The highest water values currently and in the future were identified in municipalities with a significant proportion of area growing irrigated sugarcane. Being aware of current water values of each user in a baseline year and in a projected future under global climate and socioeconomic changes, decision makers should improve water allocation policies at local scale, in order to avoid conflicts and unsustainable development in the future.     

The BIOTA Biodiversity Observatories in Africa—a standardized framework for large-scale environmental monitoring

The international, interdisciplinary biodiversity research project BIOTA AFRICA initiated a standardized biodiversity monitoring network along climatic gradients across the African continent. Due to an identified lack of adequate monitoring designs, BIOTA AFRICA developed and implemented the standardized BIOTA Biodiversity Observatories, that meet the following criteria (a) enable long-term monitoring of biodiversity, potential driving factors, and relevant indicators with adequate spatial and temporal resolution, (b) facilitate comparability of data generated within different ecosystems, (c) allow integration of many disciplines, (d) allow spatial up-scaling, and (e) be applicable within a network approach. A BIOTA Observatory encompasses an area of 1?km² and is subdivided into 100 1-ha plots. For meeting the needs of sampling of different organism groups, the hectare plot is again subdivided into standardized subplots, whose sizes follow a geometric series. To allow for different sampling intensities but at the same time to characterize the whole square kilometer, the number of hectare plots to be sampled depends on the requirements of the respective discipline. A hierarchical ranking of the hectare plots ensures that all disciplines monitor as many hectare plots jointly as possible. The BIOTA Observatory design assures repeated, multidisciplinary standardized inventories of biodiversity and its environmental drivers, including options for spatial up- and downscaling and different sampling intensities. BIOTA Observatories have been installed along climatic and landscape gradients in Morocco, West Africa, and southern Africa. In regions with varying land use, several BIOTA Observatories are situated close to each other to analyze management effects.     

Nickel induced alteration of hen body weight,egg production and egg quality after an experimental peroral administration

In this study the effects of nickel (NiCl₂) administered in drinking water (0.02; 0.2 and 2.0 mg NiCl₂/L for 28 days) on laying hen body weight, egg production and egg quality is reported. Growth parameters during the experiment were significantly decreased mainly in the group with the highest nickel concentration. In total egg production dose–dependent decrease in all experimental groups was found. Egg weight was mainly affected in the group with the highest nickel concentration. Specific egg weight was not altered. Albumen weight and albumen content was significantly decreased in groups with the highest nickel concentration in comparison with the control group.

Egg yolk analysis detected significantly decreased yolk weight in the group with the highest nickel experimental level. In yolk color a significant difference was detected between the group receiving 0.02 and 0.2 mg NiCl₂/mL. Eggshell compactness was increased in all experimental groups what could be induced by altered mineralization of eggshell. Results of this study clearly report a negative effect of nickel as an environmental pollutant on laying hen body weight, egg production as well as egg quality.     

Conditional sex allocation in the Red Mason bee, Osmia rufa

Trivers' and Willard's hypothesis that natural selection favors sex allocation in relation to maternal condition assumes iteropary. Though this assumption is not met in most solitary Aculeata, the reproductive life span of semelparous females may be divided into discrete successive cycles by the risk of open-cell parasitism. Females can avoid losing their investment to parasites attacking the open cell only by limiting the provision time for each cell. The restriction of time available for the investment in a single progeny irrespective of the condition of the female leads to de facto iteropary. Moreover, in Hymenoptera, there are no costs for sex allocation due to the haplodiploid mode of sex determination. In sexually size dimorphic species, females in poor condition are predicted to invest in the smaller sex and vice versa. The resulting prediction of a conditional sex allocation in solitary Aculeata was tested in the Red Mason bee, Osmia rufa (Osmia bicornis), a stem or hole-nesting, polylectic, univoltine megachilid bee. Body size is a key component of condition in females of nest-constructing solitary bees. Large females collect the same amount of pollen and nectar in a shorter time than small ones and should suffer less from parasitism. We found that small females dealt with their handicap of a low provisioning performance by shifting the sex ratio toward sons (the smaller sex) and by reducing the body size of daughters. Large females, however, shifted their offspring sex ratio toward daughters, the sex that depends more on body size in its reproductive value. The sex ratio in the population met the expected Fisherian sex ratio. Although females allocated their investment in the sexes according to their body mass, the population-level investment was balanced.     

Genotoxic effects of metals on human salivary gland tissue and lymphocytes as detected by the Comet assay

The etiology of salivary gland malignancies still remains unclear. Metal compounds are of special interest since they show ubiquitous presence in the environment, are present in many working places, and are accepted (co-)carcinogens in some other malignancies. Metals enter the body as xenobiotics by inhalation or ingestion. This study investigated the genotoxic potential of sodium dichromate (Na₂Cr₂O₇), nickel sulfate (NiSO₄), cadmium sulfate (CdSO₄) and zinc chloride (ZnCl₂) on human salivary gland cells and lymphocytes. Macroscopically healthy tissue of salivary glands was harvested from 46 patients during surgery and isolated to single cells by enzymatic digestion. The cells were incubated with Na₂Cr₂O₇, NiSO₄, CdSO₄ or ZnCl₂. Na₂Cr₂O₇ was also incubated in combination with the other metal compounds listed. Carcinogenic and co-carcinogenic effects of cadmium were tested by incubation with Na₂Cr₂O₇ and consecutive repair intervals. DNA damage and repair were evaluated by the Comet assay, determining DNA-strand breaks. The extent of damage was quantified using a digital analysis system. Na₂Cr₂O₇ produced significantly enhanced DNA-strand breaks in human salivary gland tissue and lymphocytes. All other metal compounds exerted no damaging effect on both cell types. Co-incubation of Na₂Cr₂O₇ with the other metals revealed a significant additive effect only for CdSO₄. Specific analysis of the influence of cadmium showed a reduction of DNA-repair after Na₂Cr₂O₇-induced strand breaks in salivary gland cells. This study provides evidence that exposure to distinct metals may significantly contribute to malignant salivary gland tumors. In consequence, further studies as epidemiological and toxicological data are warranted to determine the role of distinct metals as potential (co-) carcinogens.     

Modeling carbon sequestration under zero tillage at the regional scale. I. The effect of soil erosion

Zero tillage is recognized as a potential measure to sequester carbon dioxide in soils and to reduce CO₂ emissions from arable lands. An up-scaling approach of the output of the Environmental Policy Integrated Climate (EPIC) model with the information system SLISYS-BW has been used to estimate the CO₂-mitigation potential in the state of Baden-Württemberg (SW-Germany). The state territory of 35,742 km² is subdivided into eight agro-ecological zones (AEZ), which have been further subdivided into a total of 3976 spatial response units. Annual CO₂-mitigation rates where estimated from the changes in soil organic carbon content comparing 30 years simulations under conventional and zero tillage. Special attention was given to the influence of tillage practices on the losses of organic carbon through soil erosion, and consequently on the calculation of CO₂-mitigation rates. Under conventional tillage, mean carbon losses through erosion in the AEZ were estimated to be up to 0.45 Mg C ha⁻¹ a⁻¹. The apparent CO₂-mitigation rate for the conversion from conventional to zero tillage ranges from 0.08 to 1.82 Mg C ha⁻¹ a⁻¹ in the eight AEZ, if the carbon losses through soil erosion are included in the calculations. However, the higher carbon losses under conventional tillage compared to zero tillage are composed of both, losses through enhanced CO₂ emissions, and losses through intensified soil erosion. The adjusted net CO₂-mitigation rates of zero tillage, subtracting the reduced carbon losses through soil erosion, are between 0.07 and 1.27 Mg C ha⁻¹ a⁻¹ and the estimated net mitigation rate for the entire state amounts to 285 Gg C a⁻¹. This equals to 1045 Gg CO₂-equivalents per year with the cropping patterns in the reference year 2000. The results call attention to the necessity to revise those estimation methods for CO₂-mitigation which are exclusively or predominantly based on the measurements of differential changes in total soil organic carbon without taking into account the tillage effects on carbon losses through soil erosion.     

Benzene Exposure Assessment at Indoor, Outdoor and Personal Levels. The French Contribution to the Life MACBETH Programme

Many VOC represent hazards to human health through chronic exposure. Recent European and world-wide legislation proposes limit values for ambient concentrations of these compounds. However, very little experimental data exists for true population exposure. In 1996, the European MACBETH initiative set out to measure population exposure to benzene in six European cities. This study details the French contribution to this program. Six campaigns were carried out, each comprising measurements at 100 outdoor sites and the participation of 50 non-smoking volunteers who wore personal samplers and had passive monitors installed in their homes. Iso-concentration maps were drawn for each campaign and the results showed that outdoor concentrations were significantly lower than indoors. Almost 75% of the volunteers were exposed to mean concentrations higher than the limit value of 5µgm³. It is demonstrated that personal exposure levels cannot be deduced simply by combining indoor and outdoor background concentrations. It is also shown that there is need for better knowledge of the contributions to overall exposure of outdoor microenvironments and the authors hope that future European directives will take this into account.     

Biologische Effekte von Hexachlorbenzol (HCB) in aquatischen Modellökosystemen

A long-term study war performed on the fate and effects of hexachlorobenzene (HCB) in aquatic mesocosms. Discontinuous dosing of the sparingly soluble test substance up to the limit of its water solubility (5 μg/l at 20°C) did not cause any significant effects on the aquatic communities. From this point of view, a quality objective of 5 μg/l is considered to maintain the structures and functions of aquatic communities on a long-term scale.     

Magnetic properties of biogenic selenium nanomaterials

Environmental Science and Pollution Research - Bioreduction of selenium oxyanions to elemental selenium is ubiquitous; elucidating the properties of this biogenic elemental selenium (BioSe) is thus...