Immunotoxic effects of environmental toxicants in fish �� how to assess them?

Numerous environmental chemicals, both long-known toxicants such as persistent organic pollutants as well as emerging contaminants such as pharmaceuticals, are known to modulate immune parameters of wildlife species, what can have adverse consequences for the fitness of individuals including their capability to resist pathogen infections. Despite frequent field observations of impaired immunocompetence and increased disease incidence in contaminant-exposed wildlife populations, the potential relevance of immunotoxic effects for the ecological impact of chemicals is rarely considered in ecotoxicological risk assessment. A limiting factor in the assessment of immunotoxic effects might be the complexity of the immune system what makes it difficult (1) to select appropriate exposure and effect parameters out of the many immune parameters which could be measured, and (2) to evaluate the significance of the selected parameters for the overall fitness and immunocompetence of the organism. Here, we present - on the example of teleost fishes - a brief discussion of how to assess chemical impact on the immune system using parameters at different levels of complexity and integration: immune mediators, humoral immune effectors, cellular immune defenses, macroscopical and microscopical responses of lymphoid tissues and organs, and host resistance to pathogens. Importantly, adverse effects of chemicals on immunocompetence may be detectable only after immune system activation, e.g., after pathogen challenge, but not in the resting immune system of non-infected fish. Current limitations to further development and implementation of immunotoxicity assays and parameters in ecotoxicological risk assessment are not primarily due to technological constraints, but are related from insufficient knowledge of (1) possible modes of action in the immune system, (2) the importance of intra- and inter-species immune system variability for the response against chemical stressors, and (3) deficits in conceptual and mechanistic assessment of combination effects of chemicals and pathogens.     

Major, minor and trace element content derived from aquacultural activity of marine sediments (Central Adriatic, Croatia)

Introduction and purpose

Studies examining the environmental impact of marine aquaculture have increased significantly in number during the last few decades. The present paper investigates a region of rapid growth in intensive aquaculture and its influence on the local marine ecosystem.

Discussion

This study was undertaken with the specific aim of assessing the effect of fish farming on marine sediment at a farm near the island of Vrgada in the Central Adriatic. Data obtained regarding major (Si, Al, K, Na, Fe, Ca, Mg), minor (Mn, P, Ti) and trace (As, Au, Ba, Cd, Co, Cr, Cs, Cu, Ga, Hf, Hg, Mo, Nb, Ni, Pb, Rb, Sb, Sc, Se, Sr, Ta, Th, Tl, U, V, Y, Zn, Zr) elements were used to estimate the spatial and temporal distribution of metals in the sediment and their possible relationship with local aquacultural activity.

Results

Although the measured concentrations of heavy metals in sediment below fish cages were notably different and potentially a result of farming activity, the values were generally lower than background concentrations observed in the Central Adriatic. In contrast, concentrations of heavy metals at a reference site unaffected by aquaculture varied from lower levels to values even higher than those observed below the high-production cages. Furthermore, calculated environmental index values indicate that the sediment below the farm is either uncontaminated or suffers from only low levels of contamination.

Conclusion

Such results suggest that the effect of observed fish farm activity on the local marine ecosystem is practically negligible.     

Action of soil microorganisms on PCL and PHBV blend and films

Poly(hydroxybutyrate-co-valerate) (PHBV) and poly(ε-caprolactone) (PCL) PCL/PHBV (4:1) blend films were prepared by melt-pressing. The biodegradation of the films in response to burial in soil for 30 days was investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry (TG). The PHBV film was the most susceptible to microbial attack, since it was rapidly biodegraded via surface erosion in 15 days and completely degraded in 30 days. The PCL film also degraded but more slowly than PHBV. The degradation of the PCL/PHBV blend occurred in the PHBV phase, inducing changes in the PCL phases (interphase) and resulting in an increase of its crystalline fraction.     

Epiphytic lichen diversity in central European oak forests: Assessment of the effects of natural environmental factors and human influences

We investigated lichen diversity in temperate oak forests using standardized protocols. Forty-eight sites were sampled in the Czech Republic, Slovakia and Hungary. The effects of natural environmental predictors and human influences on lichen diversity (lichen diversity value, species richness) were analysed by means of correlation tests. We found that lichen diversity responded differently to environmental predictors between two regions with different human impact. In the industrial region, air pollution was the strongest factor. In the agricultural to highly forested regions, lichen diversity was strongly influenced by forest age and forest fragmentation. We found that several natural factors can in some cases obscure the effect of human influences. Thus, factors of naturality gradient must be considered (both statistically and interpretively) when studying human impact on lichen diversity.     

Wissenschaftstheoretische Grundlagen der Beobachtung von GVO-Umweltwirkungen

Zusammenfassung Hintergrund und Ziel  Die Exposition gentechnisch ver?nderter Kulturpflanzen erfordert die Beobachtung ihrer Umweltwirkungen. Ziel der Beitragsserie über die Beobachtung ?kologischer Wirkungen von GVO ist es, den hierzu erreichten Stand der Wissenschaft vorzustellen. Da bei einem Bundesl?nder und ggf. europ?ische Staaten übergreifenden Monitoring besonders auf methodisch vergleichbare und r?umlich aussagekr?ftige Daten zu achten ist, werden in diesem einführenden Beitrag wissenschaftstheoretische und statistische Grundlagen des Monitoring sowie die Standardisierung der Beobachtungsverfahren behandelt. Schwerpunkte  Im Mittelpunkt stehen zun?chst ?kologische Anforderungen an das GVO-Monitoring. Um mit GVO ggf. zusammenh?ngende Umweltver?nderungen ermitteln zu k?nnen, ist eine Eingliederung in bestehende Umweltbeobachtungsprogramme erforderlich. GVO-Exposition und-Wirkung sind aufeinander bezogen über die Organisationsstufen ?kologischer Systeme hinweg zu erfassen. Ein effizientes und suffizientes Monitoring bedarf eines wissenschaftstheoretisch und statistisch soliden Designs. Deshalb werden einem weiteren Schwerpunkt dieses Beitrags wissenschaftstheoretische Grundlagen der Hypothesenbildung und-prüfung behandelt. Hierfür bedarf es Daten, die mehreren, im Einzelnen behandelten Qualit?tskriterien entsprechen müssen. Eines dieser Kriterien ist die r?umliche und zeitliche Verallgemeinerungsf?higkeit der Monitoring-Befunde, die in dem dritten Schwerpunkt des Beitrags dargestellt wird. Schlussfolgerungen  Für die Prüfung von Hypothesen über Umweltfolgen von GVO sind konsequent ?kosystemforschung und Monitoring eng miteinander zu vernetzen. Denn sie erfüllen komplement?re Funktionen, die für das Monitoring der Umweltwirkungen von GVO von gro?er praktischer und wissenschaftlicher Bedeutung sind. Empfehlungen  Das GVO-Monitoring sollte in bestehende Programme der ?kosystemforschung und der Umweltbeobachtung eingebettet werden und die ?kologischen Organisationsstufen sowie GVO-Exposition und-Wirkung einschlie?en. Die Lokalisierung der Messorte sollte die erwartete Exposition oder Wirkung berücksichtigen. Perspektiven  Weitere Beitr?ge dieser Serie werden die Messplanung, das Pollenmonitoring und die r?umliche Verallgemeinerung von Ergebnissen standortspezifischer Messungen oder Modellierungen behandeln.

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Environmental monitoring of ecological impacts of GMOs

Goal, Scope and Background  The release of genetically modified organisms (GMOs) may result in ecological impacts to be monitored. This series presents the state-of-art concerning the environmental monitoring of ecological impacts of GMOs. Since this monitoring is conducted by several authorities, the methodical comparability and spatial validity of the monitoring data is crucial. Thus, the respective fundamentals of philosophy of science and of statistics as well as the methodical standardisation form the focus of this article. Main Features  At first, the monitoring requirements will be described from the viewpoint of ecology. Consequently, the GMO monitoring needs to be integrated into existing programmes. Exposure and effects of GMOs have to be monitored across the hierarchy of ecological organisation. For monitoring to be efficient and sufficient, the design must be founded in terms of philosophy of science and statistics. Hence the fundamentals concerning the verification of hypotheses represent another feature of this article. The data used for the verification of hypotheses must comply with quality criteria. One of these criteria is the spatial and temporal extrapolation of the monitoring results, which is the third feature in this introductory article. Conclusions  The evaluation of hypotheses on GMO impacts requires the linkage to ecosystems research and environmental monitoring. These both are, in terms of methodology, complementary and of significant technical and scientific value for GMO monitoring. Recommendations  GMO-monitoring should closely be connected with ecosystems research and environmental monitoring. The levels of ecological organisation should be covered as well as the exposure and the effects of GMOs. The expected GMO exposure and effects should be considered by localising the monitoring sites. Perspectives  Further articles of this series will deal with network designing, GMO pollen monitoring and extrapolation of site-specific measurements and modelling results.

     

Modeling the formation and fate of odorous substances in collection systems.

A conceptual model that simulates the formation and fate of odorous substances in branched collection systems is presented. The model predicts the activity of the relevant biomass phenotypes under aerobic, anoxic, and anaerobic conditions in force mains and gravity sewers. The formation and fate of individual, malodorous substances in the bulk water, biofilms, and sediments are modeled. The release of odorous compounds from the bulk water to the sewer gas phase, their fate in the gas phase, and their subsequent release into the urban atmosphere is simulated. Examples of model application include the prediction of hydrogen sulfide and malodorous fermentation products from force mains and gravity sewers.     

Distributions,Land-source Input and Atmospheric Fluxes of Methane in Jiaozhou Bay

CH₄ concentrations in both the surface and bottom waters of Jiaozhou Bay were determined during four surveys in 2003, which showed variability with both seasons and tidal cycles. Atmospheric fluxes of CH₄ in Jiaozhou Bay showed obvious seasonal and spatial variations, with the highest values occurring in summer and the lowest in winter. The annual emission of CH₄ from Jiaozhou Bay was estimated to be . CH₄ in the water column of Jiaozhou Bay was found to come from several land-sources including riverine water input, sewage water input and groundwater input. The spatial and temporal variation in distributions and atmospheric fluxes of CH₄ in Jiaozhou Bay was influenced mainly by the input of polluted river waters and the sewage effluents along the eastern coast, which highlights the effects of human impacts on CH₄ emission rates.     

Historical eutrophication in a river-estuary complex in mid-coast Maine.

European settlement of New England brought about a novel disturbance regime that impacted rivers and estuaries through overfishing, deforestation, dams, and water pollution. The negative consequences of these activities intensified with industrialization in the 19th and 20th centuries, often resulting in ecosystem degradation. Since environmental legislation was implemented in the 1970s, improvement in water quality has been tangible and widespread; however, ecological recovery can require substantial amounts of time and may never be complete. To document the natural baseline conditions and investigate the recovery of a severely degraded river-estuary complex in mid-coast Maine, we examined diatoms, pollen, total organic carbon, total nitrogen, stable isotopes, total phosphorus, biogenic silica, and trace metals in intertidal sediments and established a chronology with 14C, 210Pb, and indicator pollen horizons. Both climate variability and human effects were evident in the sedimentary record of Merrymeeting Bay, the freshwater tidal portion of the Kennebec estuary. Natural climate variability was apparent in an episode of high sedimentation and altered diatom abundance during the 12th and 13th centuries and in changing pollen abundances between the 16th and 19th centuries, indicative of regional cooling. During the 18th century, colonial land clearance began an era of high sedimentation and eutrophication that strongly intensified with industrialization during the late 19th and 20th centuries. Improvements in water quality over the past 30 years in response to environmental regulation had little effect on ecosystem recovery as represented by the sedimentary record. Diatom composition and productivity and high fluxes of organic C, total P, and biogenic Si in recent sediments indicate that rates of nutrient loading remain high. These environmental proxies imply that aquatic productivity in Merrymeeting Bay was originally nutrient limited and water clarity high, relative to today. Further recovery may require more stringent regulation of nutrient inputs from industrial and municipal point sources. This historical study can contribute to public debate about the environmental management of this unusual river-estuary complex by describing its long-term natural baseline, thereby illustrating the upper limit of its potential for recovery.