Chlorinated components in lime used in production contaminated citrus pulp pellets from Brazil

In order to further understand the contamination of the citrus pulp pellets (CPP) that were exported to Europe in 1997 we examined both contaminated lime and CPP samples for the distribution of polychlorinated biphenyls (PCBs) and chlorinated benzenes (tri–hexa). Standard isotope dilution techniques were applied for all samples, which were analysed by selected ion monitoring high resolution GC–MS. Lime that is used in the production of CPP product is highly contaminated with PCBs and chlorobenzenes.     

Use of avian and mammalian guilds as indicators of cumulative impacts in riparian-wetland areas

A new method of assessing cumulative effects of human activities on bird and mammal communities of riparian-wetland areas was developed by using response guilds to reflect how species theoretically respond to habitat disturbance on a landscape level. All bird and mammal species of Pennsylvania were assigned values for each response guild using documented information for each species, to reflect their sensitivity to disturbances; high guild scores corresponded to low tolerance toward habitat disturbance. We hypothesized that, given limited time and resources, determining how wildife communities change in response to environmental impacts can be done more efficiently with a response-guild approach than a single-species approach. To test the model, censuses of birds and mammals were conducted along wetland and riparian areas of a protected and a disturbed watershed in central Pennsylvania. The percent of bird species with high response-guild scores (i.e., species that had specific habitat requirements and/or were neotropical migrants) remained relatively stable through the protected watershed. As intensity of habitat alteration increased through the disturbed watershed, percentage of bird species with high response-guild scores decreased. Only 2%–3% of the neotropical migrants that had specific habitat requirements were breeding residents in disturbed habitats as compared to 17%–20% in reference areas. Species in the edge and exotic guild classifications (low guild scores) were found in greater percentages in the disturbed watershed. Composition of mammalian guilds showed no consistent pattern associated with habitat disturbance. Avian response guilds reflected habitat disturbance more predictively than mammalian response guilds.     

USE OF SYNOGRAPHIC TECHNIQUES IN RESEARCH AND DISSEMINATION OF HYDROLOGICAL INFORMATION1

ABSTRACT: Application of synographic techniques to four separate nonrelated research tasks demonstrated the usefulness of such an approach in interpreting and communicating hydrologic survey data especially when large geographic areas are involved. Nutrient exchange and biotic indicators in coastal estuaries were analyzed to determine residence times in different seasons of the year. Man induced changes in urban runoff patterns were shown to increase the probability of flooding with different recurrences of storm events. Nitrate and indicator bacteria in private wells were analyzed on a county-wide basis to determine the sources and extent of natural occurrence versus contamination origins. Water wells and the surface supply of metropolitan Houston were analyzed for sodium content to assist citizens and physicians with data which are needed for derivation of sodium restricted therapeutic diets.     

ECONOMIC EVALUATION OF WATERSHED PROJECTS - AN OVERVIEW METHODOLOGY AND APPLICATION1

ABSTRACT: Deforestation and intensive land use on a global scale has resulted in watershed deterioration and threatened municipal and irrigation reservoirs. Watershed rehabilitation programs must allocate funds to priority projects. A tool for decisionmakers is presented which provides a four-step overview economic analysis by the integration of physical and biological considerations. The overview tool is applied to a current proposed watershed project in Morocco.     

Waterborne and sediment toxicity of fluoxetine to select organisms

Ecological risk assessments of pharmaceuticals are currently difficult because little-to-no aquatic hazard and exposure information exists in the peer-reviewed literature for most therapeutics. Recently several studies have identified fluoxetine, a widely prescribed antidepressant, in municipal effluents. To evaluate the potential aquatic toxicity of fluoxetine, single species laboratory toxicity tests were performed to assess hazard to aquatic biota. Average LC(50) values for Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas were 0.756 (234 microg/l), 2.65 (820 microg/l), and 2.28 microM (705 microg/l), respectively. Pseudokirchneriella subcapitata growth and C. dubia fecundity were decreased by 0.044 (14 microg/l) and 0.72 microM (223 microg/l) fluoxetine treatments, respectively. Oryias latipes survival was not affected by fluoxteine exposure up to a concentration of 28.9 microM (8.9 mg/l). An LC(50) of 15.2 mg/kg was estimated for Chironomus tentans. Hyalella azteca survival was not affected up to 43 mg/kg fluoxetine sediment exposure. Growth lowest observed effect concentrations for C. tentans and H. azteca were 1.3 and 5.6 mg/kg, respectively. Our findings indicate that lowest measured fluoxetine effect levels are an order of magnitude higher than highest reported municipal effluent concentrations.     

Butyltin concentrations in oysters from the Gulf of Mexico from 1989 to 1991

Oyster samples from 53 Gulf of Mexico coastal sites were collected and analyzed for butyltins during 1989, 1990, and 1991. The geometric-mean tributylin concentrations were 85, 30, and 43 ng Sn/g for 1989, 1990, and 1991, respectively. The tributyltin concentrations are best represented by a log-normal distribution. A decline in the butyltin concentrations at sites with relatively low butyltin concentrations for 1989 compared with 1990 and 1991 was observed, and, at relatively high butyltin concentrations (> 400 ng Sn/g), there was hardly any difference between 1989 and 1991, but lower concentrations were present in 1990. Continued monitoring is needed in order to determine if butyltin contamination of the coastal marine environment is decreasing in response to use limitations.     

Water scarcity: An alternative view and its implications for policy and capacity building

This article focuses on the somewhat ambiguous concept of scarce water, or, more accurately stated, on the rather more ambiguous concept of scarcity. Still today, water scarcity in a region is defined largely in physical terms, typically gallons or cubic metres per capita if a stock or per capita-year if a flow. However useful purely physical measures may be for broad comparisons, they cannot adequately reflect the variety of ways in which human beings use water — neither to their wastefulness when water is perceived as abundant nor to their ingenuity when it is not. This article argues that water scarcity should be defined according to three orders of scarcity that require, respectively, physical, economic and social adaptations. It goes on to demonstrate that perceiving scarcity mainly in physical terms limits opportunities for policy-making and approaches for capacity building.     

Influence of development and rearing temperature on the distribution,ultrastructure and myosin sub-unit composition of myotomal muscle-fibre types in the plaice Pleuronectes platessa

Eggs of the plaice Pleuronectes platessa L. were incubated at temperatures of 5, 8, 10, 12 and 15°C in March 1990, 1991 and 1992. The myotomes of yolk-sac larvae contain a single superficial layer of small-diameter muscle fibres which stain intensely for succinic dehydrogenase activity, surrounding 390 to 500 weakly staining inner-muscle fibres of larger diameter. Larvae reared at 15°C only survived for a few days and had significantly more inner-muscle fibres of larger average cross-sectional area than those hatching at 5 to 10°C. Myofibrils occupied 61% of the volume of inner-muscle fibres in 15°C larvae compared with 35 and 36% in larvae hatching at 5 and 10°C, respectively (P(0.01). Following metamorphosis, which occurs between 7 and 10 wk, the myotomes retain the single layer of superficial-muscle fibres characteristic of larvae. A thickening of the superficial-muscle layer is first evident in 4 to 5 mo-old laboratory-reared fish of 20 mm total length (TL) and in 0-group fish caught in June and July. On the basis of the histochemical staining reactions for myofibrillar ATPase and succinic dehydrogenase activities, the myotomes of 1-group (104 mm TL) and adult (280 mm TL) plaice were found to contain a minimum of six distinct muscle-fibre types. Two-dimensional gel electrophoresis and peptide mapping were used to investigate changes in myosin subunit composition during development. Myosin from the inner muscle of larvae contains two isoforms of the phosphorylatable light-chain 2 (LC2_L1 and LC2_L2). Following metamorphosis and during the first year, inner-muscle fibres co-express LC2 isoforms characteristic of the superficial fast-muscle fibres of adult plaice (LC2_F1 and LC2_F2) in addition to the larval isoforms. Fast-muscle fibres isolated from deep layers of the myotomes in adult plaice only contain LC2_F2. In contrast, myosin from larval muscle and adult fast muscle contain apparently identical alkali light chains (LC1 and LC3). Peptide maps of myosin heavy chains (MHCs) from 6 wk-old larvae and 10 wk-old fish that had completed metamorphosis are similar, but distinct from those of 1-group plaice. Further changes in white-muscle MHC composition are evident between 1-group fish of 104 mm TL and adults of 280 mm TL.