Consultant Guide/1978

Abstract

Biomarkers of methyl tertiary butyl ether (MTBE) exposure and the partitioning of inhaled MTBE into the body were investigated in a human chamber study. Two subjects were exposed to an environmentally relevant nominal 5,011 µg/m³ (1.39 ppm) MTBE for 1 hour, followed by clean–air exposure for 7 hours. Breath and blood were simultaneously sampled, while total urine was collected at prescribed times before, during, and after the exposure. Mass–balance and toxicokinetic analyses were conducted based upon the time series measurement of multiple body–burden endpoints, including MTBE in alveolar breath, and MTBE and tertiary butyl alcohol (TBA) in venous blood and urine.

The decay of MTBE in the blood was assessed by fitting the post–exposure data to a 2– or 3–exponential model that yielded residence times (τ) of 2–3 min, 15–50 min, and 3–13 h as measured by alveolar breath, and 5 min, 60 min, and 32 h as evaluated from venous blood measurements. Based on observations of lower than expected blood and breath MTBE during uptake and a decreasing blood–to–breath ratio during the post–exposure decay period, we hypothesize that the respiratory mucous membranes were serving as a reservoir for the retention of MTBE. The decay data suggest that 6–9% of the MTBE intake may be retained by this non–blood reservoir. The compartmental modeling was further used to estimate important parameters that define the uptake of inhaled MTBE. The first of these parameters is f, the fraction of C_air exhaled at equilibrium, estimated as 0.60 and 0.46 for the female and male subject, respectively. The second parameter is the blood–to–breath partition coefficient (P) estimated as ～18. The product of these parameters provides an estimate of the blood concentration at equilibrium as 8–11 times the air concentration. Blood TBA lagged MTBE levels and decayed more slowly (τ = 1.5–3 h), providing a more stable indication of longer term integrated exposure.

The concentration ranges of MTBE and TBA in urine were similar to that of the blood, ranging from 0.37 to 15 µg/L and 2 to 15 µg/L, respectively. In urine, MTBE and TBA by themselves bore little relationship to the exposure. However, the MTBE:TBA ratio followed the pattern of exposure, with peak values occurring at the end of the exposure (20– and 60–fold greater than pre–exposure values) before decaying back to pre–exposure levels by the end of the 7–h decay period. Urinary elimination accounted for a very small fraction of total MTBE elimination (<1%).     

Inhibition of heavy metals on fermentative hydrogen production by granular sludge

This study was conducted to investigate the toxicity of six electroplating metals on the H(2)-producing activity of a granular sludge sampled from an H(2)-producing upflow reactor treating sucrose-containing wastewater. The H(2) production activities of the sludge were measured in serum vials using wastewater containing not just sucrose and proper nutrient, but also individual heavy metals at concentrations ranging 0-5000 mg l(-1). The relative toxicity to H(2) production was found in the following order: Cu (most toxic)>Ni approximately Zn>Cr>Cd>Pb (least toxic). The C(I,50) values, at which the bioactivity of the sludge was reduced to 50% of the control, for individual heavy metals were Cu 30 mg l(-1), Ni and Zn 1600 mg l(-1), Cr 3000 mg l(-1), Cd 3500 mg l(-1), and Pb >5000 mg l(-1). Compared with the literature data, H(2)-producing sludge exhibited in general higher resistance to metal toxicity than methanogenic granular sludge.     

Seasonal differences and within-canopy variations of antioxidants in mature spruce (Picea abies) trees under elevated ozone in a free-air exposure system

The effect of free-air ozone fumigation and crown position on antioxidants were determined in old-growth spruce (Picea abies) trees in the seasonal course of two consecutive years (2003 and 2004). Levels of total ascorbate and its redox state in the apoplastic washing fluid (AWF) were increased under double ambient ozone concentrations (2xO3), whilst ascorbate concentrations in needle extracts were unchanged. Concentrations of apoplastic and symplastic ascorbate were significantly higher in 2003 compared to 2004 indicating a combined effect of the drought conditions in 2003 with enhanced ozone exposure. Elevated ozone had only weak effects on total glutathione levels in needle extracts, phloem exudates and xylem saps. Total and oxidised glutathione concentrations were higher in 2004 compared to 2003 and seemed to be more affected by enhanced ozone influx in the more humid year 2004 compared to the combined effect of elevated ozone and drought in 2003 as observed for ascorbate.     

Pashmina production and socio‐economic changes in the Indian Changthang: Implications for natural resource management

A unique pastoral community uses the arid rangelands of eastern Ladakh, known as Changthang, northern India. The nomadic people rear a variety of livestock such as sheep, goats, horses and yaks, which provide them with various goods and services. Nevertheless, the needs and aspirations of the people are changing. There is a trend towards increasing the livestock population, especially of a breed of goat that produces one of the finest natural fibres: Pashmina, which is the mainstay of their economy. This increase in goat population, however, is jeopardising the long‐term survival of the wild herbivores in the region, and as such is not sustainable. We present information on the current trends in socio‐economy, Pashmina production, wildlife conservation, and the conflicts of interest between wildlife and nomads in the region. On the basis of this information, we make suggestions for the conservation of natural resources in the region. We recommend preserving the historical societal norms and notions of the people, and capitalising on them to manage natural resources. We also recommend joint management of natural resources by the local people, State and non‐governmental organisations. Our findings provide a platform on which a grazing policy for the region may be formulated.     

Correlation of the partitioning of dissolved organic matter fractions with the desorption of Cd,Cu, Ni,Pb and Zn from 18 Dutch soils

Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was also concentrated onto a macroreticular resin and fractionation into three operationally defined fractions: hydrophilic acids (Hyd), humic acids (HA) and fulvic acids (FA). In this manner, change in absolute solution concentration and relative percentage for each fraction could be calculated as a function of extraction equilibrium pH. The soils were also analyzed for solid phase total organic carbon and total recoverable metals (EPA Method 3051). Partitioning coefficients were calculated for the metals and organic carbon (OC) based on solid phase concentrations (less the metal or OC removed by the extraction) divided by solution concentrations. Cu and Pb concentrations in solution as a function of extract equilibrium pH are greatest at low and high pH resulting in parabolic desorption/dissolution curves. While processes such as proton competition and proton promoted dissolution can account for high solution metal concentrations at low pH, these processes cannot account for higher Cu and Pb concentrations at high pH. DOC increases with increasing pH, concurrently with the increase in Cu and Pb solution concentrations. While the absolute concentrations of FA and HA generally increase with increasing pH, the relative proportional increase is greatest for HA . Variation in HA concentrations spans three orders of magnitude while FA concentrations vary an order of magnitude over the pH range examined. Correlation analysis strongly suggests that HA plays a major role in increasing the concentration of solution Cu and Pb with increasing pH in the 18 soils studied. The percentage of the OC that was due to FA was nearly constant over a wide pH range although the FA concentration increased with increasing pH and its concentration was greater than that of the HA fraction at lower pH values (pH = 3-5). Thus, in more acidic environments, FA may play a larger role than HA in governing organo-metallic interactions. For Cd, Ni, and Zn, the desorption/dissolution pattern shows high metal solution concentrations at low pH with slight increases in solution concentrations at extremely high pH values (pH>10). The results presented here suggest that the effects of dissolved organic carbon on the mobilization of Cd, Ni, and Zn may only occur in systems governed by very high pH. At high pH, it is difficult to distinguish in this study whether the slightly increased solution-phase concentrations of these cations is due to DOC or hydrolysis reactions. These high pH environments would rarely occur in natural settings.     

Meister

A mobile remote sensing system is presented for measuring the concentration of gaseous pollutants in ambient air and in directed effluent streams. MEISTER is based on Fourier-Transform-Infrared-Spectroscopy (FTIS), which is predestinated for a simultaneous analysis of a large number of atmospheric gases. The Kayser-Threde Double-Pendulum interferometer K300 and the Multicomponent Air Pollution Software (MAPS) of the Fraunhofer Institute of Atmospheric Environmental Research, which is based on radiative transfer modeling and least square fit procedures, enable a concentration determination under almost all meteorological conditions. CO, CO₂, NO, N₂O, CH₄, H₂O and HCl concentrations have been determined in good agreement with results from conventionalin situ sensors. NO₂, SO₂, NH₃, HCHO and hydrocarbons have been successfully detected provided their concentrations were high enough.     

Advancing objectives-based,integrated ocean management through marine spatial planning: current and future directions on the Scotian Shelf off Nova Scotia,Canada

The national legislative and policy context for integrated ocean management in Canada is provided by the Oceans Act (1996) and the supporting policy statement, Canada’s Oceans Strategy. Under the Oceans Act, Fisheries and Oceans Canada (DFO) is the lead federal authority for ocean affairs and is charged with leading and facilitating the development and implementation of integrated management plans for all marine waters. Integrated management efforts in Canada are being undertaken through an area-based approach that enables marine planning, management and decision making to occur at appropriate spatial scales, from regional to site-specific. This article focuses on the Eastern Scotian Shelf Integrated Management (ESSIM) process, an offshore-focused effort to develop an integrated ocean management plan for a large portion of the Scotian Shelf, off Nova Scotia. The resulting Eastern Scotian Shelf Integrated Ocean Management Plan (the ESSIM plan) has been developed through a collaborative process involving all interested and affected government departments and ocean stakeholders, and provides an objectives-based approach to ocean management. The ESSIM plan contains a set of long-term, overarching goals for collaborative governance and integrated management, sustainable human use, and healthy ecosystems. These goals are supported by more specific objectives that express desired outcomes and conditions for the marine region. The objectives-based approach seeks to ensure that interrelationships among ecosystem and human use objectives are recognized and reflected in the identification of management strategies and supporting actions. This article considers the role of marine spatial planning within the context of the integrated ocean management process underway for the Scotian Shelf. The policy and management context for integrated ocean management in Canada is briefly described and a summary of the ESSIM plan is provided. The current and potential role for marine spatial planning in implementing the objectives and strategies of the ESSIM plan is highlighted using examples related to multiple ocean use and marine conservation and protected area planning. The article concludes by drawing out key lessons learned to date through the ESSIM process for marine spatial planning and looks to the future in terms of the development of tools and approaches for this integral aspect of integrated ocean management.     

White tail markings are an indicator of quality and affect mate preference in rock sparrows

In birds, colourful and elaborate feathers are important traits in mate choice. Distinct tail white patches are present in many species of birds, but they remain little studied. Tail markings may indeed have a signal function because in many species males spread the tail offering a good view of these markings to females during courtship behaviour. Here, we investigated whether white tail spots in male rock sparrow, Petronia petronia, play a role in mate choice. In a free-living population of rock sparrows, we found a reduction in white tail spots size as the breeding season progressed due to abrasion, which was expected if tail spots act as a reliable quality indicator (i.e. a handicap). The same reduction was found under captive conditions, and males in worse condition (individuals that lost more weight) abraded a bigger part of white. This suggests that white tail markings are an indicator of male quality. In captivity, we measured female preference for males differing in white patch size in a mate choice experiment. The experimental reduction of the size of the males’ white spots resulted in a lower sexual interest by females. During courtship display, male rock sparrow shows a yellow breast patch (a carotenoid-based, sexually selected ornament) together with the white spots in the tail. The sizes of these two traits are positively correlated, but only the abraded white area in the tail correlates with a surrogate of individual quality (lost of weight). In conclusion, we can assert that the size of the white spots is preferred by female rock sparrows and it is a part of a multiple signal system.     

Conservation overstretch and long-term decline of wildlife and tourism in the Central African savannas

When in 2010 the world's governments pledged to increase protected area coverage to 17% of the world's land surface, several Central African countries had already set aside 25% of their northern savannas for conservation. To evaluate the effectiveness of this commitment, we analyzed the results of 68 multispecies surveys conducted in the seven main savanna national parks in Central Africa (1960–2017). We also assembled information on potential drivers of large herbivore population trends (rainfall and number of rangers) and on tourist numbers and revenues. In six out of the seven parks, wild large herbivore populations declined dramatically over time, livestock numbers increased severalfold, and tourism, the pillar under a once thriving local wildlife industry, collapsed. Zakouma National Park (Chad) stood out because its large herbivore populations increased, an increase that was positively correlated with rainfall and number of rangers (a proxy for management inputs). With increasing insecurity and declining revenues, governments find themselves confronted with too few resources to protect vast areas. To deal with this conversation overstretch, we propose to extend the repeatedly promoted solutions––scaled up funding, enhanced management––with a strategic retreat, focusing scarce resources on smaller areas to save wildlife in the Central African savannas.