Effects of watershed-scale land use change on stream nitrate concentrations

The Walnut Creek Watershed Monitoring Project was conducted from 1995 through 2005 to evaluate the response of stream nitrate concentrations to changing land use patterns in paired 5000-ha Iowa watersheds. A large portion of the Walnut Creek watershed is being converted from row crop agriculture to native prairie and savanna by the U.S. Fish and Wildlife Service at the Neal Smith National Wildlife Refuge (NSNWR). Before restoration, land use in both Walnut Creek (treatment) and Squaw Creek (control) watersheds consisted of 70% row crops. Between 1990 and 2005, row crop area decreased 25.4% in Walnut Creek due to prairie restoration but increased 9.2% in Squaw Creek due to Conservation Reserve Program (CRP) grassland conversion back to row crop. Nitrate concentrations ranged between <0.5 to 14 mg L(-1) at the Walnut Creek outlet and 2.1 to 15 mg L(-1) at the downstream Squaw Creek outlet. Nitrate concentrations decreased 1.2 mg L(-1) over 10 yr in the Walnut Creek watershed but increased 1.9 mg L(-1) over 10 yr in Squaw Creek. Changes in nitrate were easier to detect and more pronounced in monitored subbasins, decreasing 1.2 to 3.4 mg L(-1) in three Walnut Creek subbasins, but increasing up to 8.0 and 11.6 mg L(-1) in 10 yr in two Squaw Creek subbasins. Converting row crop lands to grass reduced stream nitrate levels over time in Walnut Creek, but stream nitrate rapidly increased in Squaw Creek when CRP grasslands were converted back to row crop. Study results highlight the close association of stream nitrate to land use change and emphasize that grasslands or other perennial vegetation placed in agricultural settings should be part of a long-term solution to water quality problems.     

The combined effect of uranium and gamma radiation on biological responses and oxidative stress induced in Arabidopsis thaliana

Uranium never occurs as a single pollutant in the environment, but always in combination with other stressors such as ionizing radiation. As effects induced by multiple contaminants can differ markedly from the effects induced by the individual stressors, this multiple pollution context should not be neglected. In this study, effects on growth, nutrient uptake and oxidative stress induced by the single stressors uranium and gamma radiation are compared with the effects induced by the combination of both stressors. By doing this, we aim to better understand the effects induced by the combined stressors but also to get more insight in stressor-specific response mechanisms. Eighteen-day-old Arabidopsis thaliana seedlings were exposed for 3 days to 10 μM uranium and 3.5 Gy gamma radiation. Gamma radiation interfered with uranium uptake, resulting in decreased uranium concentrations in the roots, but with higher transport to the leaves. This resulted in a better root growth but increased leaf lipid peroxidation. For the other endpoints studied, effects under combined exposure were mostly determined by uranium presence and only limited influenced by gamma presence. Furthermore, an important role is suggested for CAT1/2/3 gene expression under uranium and mixed stressor conditions in the leaves.     

Building Local Community Commitment to Wetlands Restoration: A Case Study of the Cache River Wetlands in Southern Illinois, USA

Natural resource professionals are increasingly faced with the challenges of cultivating community-based support for wetland ecosystem restoration. While extensive research efforts have been directed toward understanding the biophysical dimensions of wetland conservation, the literature provides less guidance on how to successfully integrate community stakeholders into restoration planning. Therefore, this study explores the social construction of wetlands locally, and community members’ perceptions of the wetland restoration project in the Cache River Watershed of southern Illinois, where public and private agencies have partnered together to implement a large-scale wetlands restoration project. Findings illustrate that the wetlands hold diverse and significant meanings to community members and that community members’ criteria for project success may vary from those identified by project managers. The case study provides managers with strategies for building community commitment such as engaging local citizens in project planning, minimizing local burdens, maximizing local benefits, and reducing uncertainty.     

Converging impact assessment discourses for sustainable development: the case of Flanders,Belgium

The scientific field of impact assessment encompasses various ‘traditions’, each reflecting a set of particular policy objectives. This paper analyses two types of impact assessment. Regulatory impact analysis focuses on better regulation and competitiveness, while sustainability assessment fosters a holistic approach centred on the values of sustainable development. Through an analysis of the political discourses at the level of the European Union and at the sub-national level of the Flemish Region of Belgium, elements of convergence between the better regulation and sustainable development discourse are identified. The paper analyses how integrated impact assessment can be an integrative tool that allows to merge both discourses and to implement them in day-to-day decision-making. The potential of the existing Flemish regulatory impact analysis framework to be the starting point of an integrated assessment scheme for sustainable development is advocated and motivated.     

Fluorescence Verses Radioactivity Labeling for Lab-Scale Investigation of the Fate of Water-Soluble Polymers in Wastewater Treatment Plants

Water-soluble synthetic polymers are extensively used in cosmetics, detergents and paints. Many end up in wastewater and, later on, in wastewater-treatment plants. In order to gain an insight into their fate in such plants, fluorescence and radioactivity labelings were compared using a lab-scale reactor designed to mimic industrial conditions. Two fermentation media were considered, namely a mixture of E402 and E204 micro-organisms and an activated sludge collected from a water-treatment plant located in the south of France. A sample of low molar mass commercial poly(acrylic acid) (PAA) was labeled by radioactivity with tritium and by coupling the 6-aminofluorescein fluorescent dye. Labeled PAA-containing sludges were allowed to ferment. To monitor the fate of the polymers, aliquots of the fermented mixtures were withdrawn at selected times and centrifuged. Liquid and solid phases were analyzed by scintigraphy or UV spectrometry, depending of the labeling techniques. Both techniques led to similar distributions, c.a. 75% in the supernatant and 25% in the solid phase. Distributions remained constant during the biological tests. There was no degradation of the commercial PAA after aqueous size exclusion chromatography (SEC), in agreement with literature. These features showed that fluorescence-labeling can be used instead of the complex and expensive radiolabeling. The validated fluorescence-based method was then applied to a linear poly(acrylic acid) synthesized by ATRP and labeled with 6-aminofluorescein. There was no significant difference between the commercial and the linear poly(acrylic acid)s. In contrast, a linear PAA with 5% of tert-butyl ester repeating units was predominantly found in the solid phase although adsorption or absorption by micro-organisms could not be demonstrated. The method based on fluorescence labeling should be applicable to other water soluble polymers provided that the dye remains attached to the polymer as it was the case for the studied poly(acrylic acid)s.     

Organizational and Operational Techniques for Relieving Manpower Shortages in Air Pollution Control Agencies

Many governmental air pollution control agencies are confronted with a shortage of manpower, both in terms of numbers of people and qualifications of available staff members. This paper discusses a number of techniques which may be used to relieve this manpower shortage. The techniques are discussed in terms of collaboration between state and local agencies; organizational structures which make maximum use of scarce categories of people; program policies which conserve the time of agency staff; operating schemes which save travel time and minimize skills required; and working tools that can be used to get the greatest production with available personnel.     

Histopathological lesions and DNA adducts in the liver of European flounder (Platichthys flesus) collected in the Seine estuary versus two reference estuarine systems on the French Atlantic coast

An epidemiological survey was conducted in the Seine estuary and in two smaller and relatively preserved estuaries on the French Atlantic coast in order to estimate the occurrence of liver lesions in European flounder, Platichthys flesus, and also to seek putative risk factors for the recorded pathologies. Four hundred and seventy-eight fish of both sexes and of different size ranges were sampled in the three studied areas, 338 of which in the Seine estuary. All fish were examined for histopathological liver lesions, while DNA adducts and otoliths were analyzed on a subsample. Five categories of hepatic lesions were recorded with the following prevalence for the Seine estuary: 36.7 % inflammations, 8 % parasites (mainly encysted nematodes), 6.5 % foci of cellular alteration (FCA), 5.3 % foci of necrosis or regeneration (FNR), and 1.5 % tumors. Inflammation occurrence increased according to age, contrary to parasitic infestations and FCA which were more prevalent in young fish, notably those of <1 year old (group 0). Tumors were only observed in females of more than two winters. Females exhibited a higher prevalence of tumors (3.0 %) and FCA (6.5 %) than males (0 and 2.6 %, respectively). Parasitic and infectious lesions and FNR were equally distributed in males and females. The prevalence of FNR was also shown to vary according to sampling season, with significantly more occurrences of liver necrosis in the fish collected in summer than in spring. Spatial differences were observed with a higher occurrence of encysted parasites in flounders from the upper Seine estuary, while inflammations predominated in flounders living downstream. Temporal trends were also noted, with an increased prevalence of parasitic infestations, inflammations, and FCA in the 2002–2003 period in comparison to the 1996–1997 one. The three flounder populations from the Seine estuary (Normandy), Ster estuary (Brittany), and Bay of Veys (Normandy) showed different spectra of hepatic lesions. Flounders from the Bay of Veys had relatively few liver lesions as compared to flounders from the two other estuaries. Flounders from the Ster estuary exhibited the highest prevalence of parasites (37.2 %) and inflammations (51.1 %). Finally, FCA and liver tumors occurred at very similar levels in both flounder populations from the Seine and the Ster estuaries. Group 0 flounders inhabiting the upper Seine estuary were more prone to parasitic and pre-neoplastic hepatic lesions and had higher levels of liver DNA adducts than the older ones living downstream. It was postulated that group 0 European flounders may serve as valuable bioindicators for assessing the quality of estuarine waters and the health status of euryhaline fish populations.     

Responses of juvenile European flounder (Platichthys flesus) to multistress in the Vilaine estuary, during a 6-month survey

Physiological and genetic responses of age 0+ Platichthys flesus were investigated in the eutrophicated and moderately contaminated Vilaine estuary, during a 6-month survey. The main objective of this study was to explore the biological responses of fishes during their juvenile period in an estuarine system in order to detect a possible selective pressure induced by the environmental stress. Our results showed a general convergence in physiological responses along the survey: an increase in genotoxicity was associated with an increase in mRNA expression of ATPase and betaine homocysteine methyltransferase. These results could suggest an increase of cellular damage, energetic request, and detoxification rate related to the growing exposure time to stress. Considering the aging of the cohort, the genetic characteristics of the Vilaine flounder cohort came closer to the one observed in a highly stressed system, the Seine estuary, suggesting a potential selective pressure mainly induced by the chemical stress.     

Public Reaction to Air Pollution in Nashville,Tennessee

Extensive air pollution studies have been completed in Nashville. One part of the study involved collection of opinions from nearly 8000 people. Opinions were solicited relative to awareness and concern about possible adverse effects of air pollution on health, property, materials, and aesthetics. Responses of the interviewed people are related to several types of pollutant measurements. The results indicate widespread concern about air pollution, and the degree of concern is, in general, closely related to the degree of air contamination experienced by interviewed people. Methodology is discussed, data are analyzed statistically, and conclusions are presented.     

Effects of mono-(2-ethylhexyl) phthalate (MEHP) on chicken germ cells cultured in vitro

In recent decades, many toxicological tests based on in vivo or in vitro models, mainly from mammalian (rat–mouse) and fish species, were used to assess the risks raised by contact or ingestion of molecules of pharmaceutical, agricultural, or natural origin. But no, or few, in vitro tests using other non-mammalian models such as bird have been explored despite their advantages: the embryonic gonads of birds have a high plasticity of development sensitive to estrogen, and sperm production is nearly two times faster than in rodents. Hence, we have established an in vitro culture of germ cells and somatic cells from chicken post-natal testis, and we have evaluated the sensitivity against the endocrine disruptor compound mono-(2-ethylhexyl) phthalate (MEHP) in comparison to previous studies using rodent and human models. After 96 h of exposure in presence of 10 μM MEHP, chicken seminiferous tubules cultures present a structural alteration, a reduction in cell proliferation and in germ cells population. Apoptosis of germ and somatic cells increases in presence of 1 μM MEHP. Furthermore, MEHP does not affect inhibin B and lactate production by Sertoli cells. These results are in accordance with previous studies using rat, mice, or human culture of testicular cells and in similar range of exposures or even better sensitivity for some “end-points” (biological parameters). In conclusion, the establishment of this postnatal testicular cells culture could be considered as an alternative method to in vivo experiments frequently used for evaluating the impact on the terrestrial wildlife species. This method could be also complementary to mammal model due to the limiting number of animals used and its elevated sensitivity.