Geese and dietary allelochemicals — food palatability and geophagy

Summary The palatability of plants was studied in young, immature and adult geese of three species,Anser anser, Anser indicus andBranta canadensis, with respect to secondary plant metabolites. In their first 1–4 weeks of life, hand-reared goslings feed on a wide variety of plants, more or less irrespective of their allelochemical contents. Older birds become more selective, but still consume plants which are normally considered to be unpalatable or even toxic for other animals. Choice experiments were performed with pure secondary metabolites which were offered on otherwise highly palatable food items, such as leaves ofTaraxacum officinale. These experiments revealed a similar trend, in that very young goslings discriminate their food much less than older goslings or adult geese. In general, food contaminated with essential oils was rejected, whereas alkaloids, glycosides, amines and sulfur compounds were tolerated to a remarkable degree. In consequence, especially young, but also adult geese must have a high capacity to tolerate and/or to detoxify dietary allelochemicals. Another detoxification mechanism became evident during the experiments: geese ingest soil and mud quite regularly. It could be shown experimentally that the respective soil had a high capacity to bind alkaloids. We assume that geophagy is a means (besides a presumed active detoxification in the liver) to adsorb and thus reduce the contents of dietary allelochemicals.     

Veränderung der Zinktoxizität in Wässern geringer und hoher Wasserhärte unter dem Einfluß eines synthetischen Huminstoffes

In soft water 5mg/l of a synthetic dissolved humic substance (HS) reduced the toxicity of zinc against zebrafish embryo and larvae. The appliation of this HS as an antidot against fish hazardous zinc concentrations particulary in soft water is possible. In hard water the HS is able to change the detoxification effect of high water hardness because of the interaction between the calcium and magnesium ions and the HS. In this case the protective effect of high water hardness against trace metals is reduced because of the adhesion of hardness producing ions (Ca²⁺, Mg²⁺) with the HS.     

A controversy re-visited: Is the coccinellid Adalia bipunctata adversely affected by Bt toxins?

Background

The Cefic Mixtures Industry Ad-hoc Team (MIAT) has investigated how risks from combined exposures can be effectively identified and managed using concepts proposed in recent regulatory guidance, new advances in risk assessment, and lessons learned from a Cefic-sponsored case study of mixture exposures.

Results

A series of tools were created that include: a decision tree, a system for grouping exposures, and a graphical tool (the MCR-HI plot). The decision tree allows the division of combined exposures into different groups, exposures where one or more individual components are a concern, exposures that are of low concern, and exposures that are a concern for combined effects but not for the effects of individual chemicals. These tools efficiently use available data, identify critical data gaps for combined assessments, and prioritize which chemicals require detailed toxicity information. The tools can be used to address multiple human health endpoints and ecological effects.

Conclusion

The tools provide a useful approach for assessing risks associated with combined exposures to multiple chemicals.     

Pteris vittata – Revisited: Uptake of As and its speciation, impact of P, role of phytochelatins and S

Pteris vittata is known to hyperaccumulate As but the mechanism is poorly understood. We found an increase of As concentration with increasing soil solution As concentrations, but P application had no impact, although plant P concentrations responded to different rates of P supply. As in fronds was dominantly (82–89%) present in the form of AsIII. In roots we detected 45% as AsIII which is higher than reported in previous studies and supports substantial As-reduction to take place in roots. We detected PC2/3GS–AsIII, PC2–GS–AsIII and (PC2)2–AsIII in increasing amounts with application of As. The total amount of PC was in the range reported previously and far too small to assign a significant role in As detoxification to PCs. The close correlation between S and As in fronds and the lack of data on sulphur uptake and metabolism indicates the need for a detailed investigation on sulphur nutritional status and As metabolism in P. vittata.     

GC-MS analyses and chemometric processing to discriminate the local and long-distance sources of PAHs associated to atmospheric PM2.5

Purpose

This study presents a procedure to differentiate the local and remote sources of particulate-bound polycyclic aromatic hydrocarbons (PAHs).

Methods

Data were collected during an extended PM_2.5 sampling campaign (2009?C2010) carried out for 1?year in Venice-Mestre, Italy, at three stations with different emissive scenarios: urban, industrial, and semirural background. Diagnostic ratios and factor analysis were initially applied to point out the most probable sources. In a second step, the areal distribution of the identified sources was studied by applying the discriminant analysis on factor scores. Third, samples collected in days with similar atmospheric circulation patterns were grouped using a cluster analysis on wind data. Local contributions to PM_2.5 and PAHs were then assessed by interpreting cluster results with chemical data.

Results

Results evidenced that significantly lower levels of PM_2.5 and PAHs were found when faster winds changed air masses, whereas in presence of scarce ventilation, locally emitted pollutants were trapped and concentrations increased. This way, an estimation of pollutant loads due to local sources can be derived from data collected in days with similar wind patterns. Long-range contributions were detected by a cluster analysis on the air mass back-trajectories. Results revealed that PM_2.5 concentrations were relatively high when air masses had passed over the Po Valley. However, external sources do not significantly contribute to the PAHs load.

Conclusions

The proposed procedure can be applied to other environments with minor modifications, and the obtained information can be useful to design local and national air pollution control strategies.     

Origin of Antarctic Isopoda (Crustacea,Malacostraca)

An analysis of the horizontal and the vertical zonation of the Antarctic Isopoda, combined with knowledge of the geological history of Antarctica and isopod phylogeny, revealed that the isopod family Serolidae and subfamily Arcturinae are likely to have evolved from ancestors that inhabited a cold-temperate Gondwanian province. Antarctic species of other families, such as the Munnopsidae, Nannoniscidae, Desmosomatidae and Ischnomesidae, are likely to have evolved from deep-sea ancestors. It is deduced that emigration of South Patagonian species into the Southern Ocean, although possible, probably did not occur very often. Evolutionary phenomena such as continental-drift vicariance, radiation of species on the continental shelf of Antarctica, and active migration, including submergence and emergence mechanisms are discussed.     

Radiocesium storage in soil microbial biomass of undisturbed alpine meadow soils and its relation to 137Cs soil-plant transfer

This study focuses on radiocesium storage in soil microbial biomass of undisturbed alpine meadow sites and its relation to the soil-to-plant transfer. Soil and plant samples were taken in August 1999 from an altitude transect (800-1600m.a.s.l.) at Gastein valley, Austria. Soil samples were subdivided into 3-cm layers for analyses of total, K(2)SO(4)-extractable and microbially stored (137)Cs. Microbial biomass was measured by the fumigation extraction method, and fungal biomass was quantified using ergosterol as biomarker molecule. In general, the quantity of (137)Cs stored in the living soil microbial biomass was relatively small. At the high-altitude meadows, showing high amounts of fungal biomass, microbially stored (137)Cs amounted to 0.64+/-0.14kBqm(-2) which corresponds to about 1.2-2.7% of the total (137)Cs soil inventory. At lower altitudes, microbial (137)Cs content was distinctly smaller and in most cases not measurable at all using the fumigation extraction method. However, a positive correlation between the observed soil-to-plant aggregated transfer factor, microbially stored (137)Cs and fungal biomass was found, which indicates a possible role of fungal biomass in the storage and turnover of (137)Cs in soils and in the (137)Cs uptake by plants.