Assimilation,inter-organ transfer and excretion of americium in two teleost fish

Radiotracer experiments were performed (February–April, 1982) to study the assimilation and metabolism of the transuranium nuclide americium-241 in the marine teleosts Serranus scriba (Linnaeus, 1758) and Scorpaena notata Rafinesque, 1810, caught off the Monaco coast. Fish fed with ²⁴¹Am-labelled food showed that assimilation of this radionuclide takes place through the gastrointestinal walls and that the small fraction accumulated is incorporated mainly in the skin, muscle and skeleton. Gut-transfer coefficients were similar in both species and averaged 0.7% (range 0.1 to 1.7%) of the ingested activity. The calculated biological half-lives for loss of the absorbed fraction ranged between 49 and 61 d for Serranus scriba and 12 and 117 d for Scorpaena notata. Results from an intramuscular injection experiment indicated that ²⁴¹Am was retained mainly in the liver, skin and skeleton; the fraction accumulated by muscle was very low. Liver displayed a relatively short biological half-time for ²⁴¹Am loss of roughly 24 d. Routes of ²⁴¹Am excretion from the teleosts appear to be through the kidneys, gills and feces with bile serving as a possible excretion route from the liver. From the limited amount of published information available for comparison, experimental evidence is presented which suggests that ²⁴¹Am taken up via the food chain is more biologically available to marine fish than is plutonium.     

Loft features influence the processing of navigational information by pigeons

The present study evaluates the impact of lofts on the development of the navigational system of pigeons. A series of results obtained between 2000 and 2004 were analyzed. The H-loft was placed 10 m above the ground, with a ring format and seven windows all around it as well as three external aviaries that allowed birds to have a wide view of the outdoors and of the sky and knowledge of the wind dynamics. The L-loft was placed at ground level, with a single window transformed into an external aviary. The L-loft was protected from the wind by surrounding trees, reducing the ability of the pigeons to access the wind dynamics and also restricting their access to information regarding the outside area and the sky. In a preliminary analysis, we found the parameter of “vanishing time” to differ significantly between lofts in two of the five age classes. A thorough analysis of this parameter throughout the ontogenetic development of the birds demonstrated a pronounced improvement in the information-processing system with age, with adults vanishing quicker than younger birds, although an impairment of development occurred during the third month of age, perhaps due to a reorganization of the system. This result was obtained when the effect of lofts was considered in the different age classes. Results suggest that loft features are an important factor in the ability of the young pigeons to exploit navigational cues.     

PCB and DDT contamination in cultivated and wild sea bass from Ria de Aveiro, Portugal

Polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) and metabolites were quantified in muscle and liver of sea bass (Dicentrarchus labrax) collected in Ria de Aveiro and in two fish farms. Sea bass from natural environment showed lower levels than fish from farming, which may be partly attributed to the higher lipid content of cultivated fish. PCB congener distribution in tissues of sea bass from the two farms resembled that of diet pellets suggesting that commercial diet is a major source of PCBs. However, fish in the two sites were fed with diet of similar PCB and DDT contamination but showed distinct levels in its tissues not explained by lipid content.     

Using thermal units for estimating critical period of weed competition in off-season maize crop

Brazilian off-season maize production is characterized by low yield due to several factors, such as climate variability and inadequate management practices, specifically weed management. Thus, the goal of this study was to determinate the critical period of weed competition in off-season maize (Zea mays L.) crop using thermal units or growing degree days (GDD) approach to characterize crop growth and development. The study was carried out in experimental area of the University of S?o Paulo, Brazil, with weed control (C), as well as seven coexistence periods, 2, 4, 6, 8, and 12 leaves, flowering, and all crop cycle; fourteen treatments were done. Climate data were obtained from a weather station located close to the experimental area. To determine the critical period for weed control (CPWC) logistic models were fitted to yield data obtained in both W and C, as a function of GDD. For an arbitrary maximum yield loss fixed in 2.5%, the CPWC was found between 301 and 484 GDD (7-8 leaves). Also, when the arbitrary loss yield was fixed in 5 and 10%, the period before interference (PBI) was higher than the critical weed-free period (CWFP), suggesting that the weeds control can be done with only one application, between 144 and 410 GDD and 131 and 444 GDD (3-8 leaves), respectively. The GDD approach to characterize crop growth and development was successfully used to determine the critical period of weeds control in maize sown off-season. Further works will be necessary to better characterize the interaction and complexity of maize sown off-season with weeds. However, these results are encouraging because the possibility of the results to be extrapolated and because the potential of the method on providing important results to researchers, specifically crop modelers.     

Bioaccumulation and elimination of 14C-lindane by Enchytraeus albidus in artificial (OECD) and a natural soil

Bioaccumulation and elimination of 14C-lindane in Enchytraeus albidus was studied in artificial OECD soil and a silty loam from an agricultural field in Central West Portugal. Results showed that enchytraeids were able to bioaccumulate the chemical with a kinetic pattern similar to that of earthworms: fast uptake within a few days and a biphasic elimination pattern. A 10 day period to study uptake was sufficient, but a few more days were probably necessary for elimination. Bioaccumulation was influenced by soil type. The authors suggest that higher organic matter (OM) content and also the higher content on sand particles in the OECD soil may have led to a faster elimination: hydrophobic chemicals tend to adsorb to OM being in this way less bioavailable and therefore less bioaccumulated having bioaccumulation factor value around 6 while in natural soil is 10; the sand could act as abrasive particles (helpers) in the elimination process leading to an elimination of 90% of the chemical in two days while in natural soil 67% was eliminated in the same period of time.     

Influence of air pollution on the incidence of respiratory tract neoplasm

To evaluate the possible influence of air pollutants on the incidence of respiratory tract neoplasm we studied 12 S?o Paulo City districts where air pollution is observed. We collected data on pollutants from 1981-1990 and correlated it with the incidence of larynx and lung neoplasms in 1997. Ozone was the pollutant that best correlated with the incidence of neoplasm. The correlation coefficients were 0.7234 (p=0.277) and 0.9929 (p=0.007) for lung and larynx cancer, respectively. There may be a relationship between air pollution and the incidence of respiratory tract neoplasm. This study, however, does not allow us to conclude that there is a causal relationship.     

Air quality management in Portugal: example of needs and available tools

The Framework Directive (FWD) and the proposed Daughter Directives are the newest legislative instruments concerning a new political strategy and air quality management approach for Europe. Additionally, the member countries of the United Nations Economic Commission for Europe have included the concepts of critical load and level for planning air pollution abatement strategies and as a base of international agreements concerning limitation of the emissions of air pollutants. These concepts imply an accurate knowledge about pollutants deposition fluxes. The paper describes the main needs and the tools available to define a strategy of air quality management in Portugal. Two study cases are presented: (1) extensive monitoring plan to assess the impact of an urban incinerator plant; and (2) contribution to a methodology to estimate critical levels for a coastal region in Portugal. These different approaches allowed illustrating the complexity of the implementation of an air pollution management strategy.     

Valuation of natural marine ecosystems: an economic perspective

This paper attempts to examine whether information from valuation studies can help the design of policies adequate to reverse and halt the generally poor state of marine and coastal ecosystems of the Mediterranean and the Black Sea. Economic implications of managing coastal and marine environments are thus discussed by assessing the results of different valuation studies implemented in the area. Lessons and policy recommendations from existing literature are inferred to guide marine resources management decisions. One of our main findings is that there are extremely few published studies within the Mediterranean and Black Sea region which highlights the potential for future research on coastal and marine ecosystems ability to sustain different goods and services as a result of climate change and anthropogenic drivers in the area. However, results reveal that there are substantial positive economic values attached to marketed and non-marketed services provided by marine and coastal ecosystems that justify their sustainable use and management.     

A strategy for the next decade to address data deficiency in neglected biodiversity

Measuring progress toward international biodiversity targets requires robust information on the conservation status of species, which the International Union for Conservation of Nature (IUCN) Red List of Threatened Species provides. However, data and capacity are lacking for most hyperdiverse groups, such as invertebrates, plants, and fungi, particularly in megadiverse or high-endemism regions. Conservation policies and biodiversity strategies aimed at halting biodiversity loss by 2020 need to be adapted to tackle these information shortfalls after 2020. We devised an 8-point strategy to close existing data gaps by reviving explorative field research on the distribution, abundance, and ecology of species; linking taxonomic research more closely with conservation; improving global biodiversity databases by making the submission of spatially explicit data mandatory for scientific publications; developing a global spatial database on threats to biodiversity to facilitate IUCN Red List assessments; automating preassessments by integrating distribution data and spatial threat data; building capacity in taxonomy, ecology, and biodiversity monitoring in countries with high species richness or endemism; creating species monitoring programs for lesser-known taxa; and developing sufficient funding mechanisms to reduce reliance on voluntary efforts. Implementing these strategies in the post-2020 biodiversity framework will help to overcome the lack of capacity and data regarding the conservation status of biodiversity. This will require a collaborative effort among scientists, policy makers, and conservation practitioners.