New insights into the endocrine disrupting effects of brominated flame retardants

The objective of this review is to provide an overview of recent studies demonstrating the endocrine disrupting (ED) effects of brominated flame retardants (BFRs), while highlighting interesting data presented at the recent international BFR workshop in Amsterdam in April, 2007. A review written in 2002 was used as a starting point and about 60 publications published since 2003 were reviewed. New insights into the in vivo effects of BFRs on thyroid hormone, estrogen and androgen pathways in both mammalian and non-mammalian models are provided, and novel (in vitro) findings on the mechanisms underlying ED effects are highlighted. Special attention is also given to reports on neurotoxicological effects at relatively low doses of BFRs, although an endocrine-related mechanism is disputable. Convincing evidence has been published showing that BFRs and importantly, BFR metabolites, have the potential to disrupt endocrine systems at multiple target sites. While some studies suggest a wide margin of safety between effect concentrations in rodent models and levels encountered in humans and the environment, other studies demonstrate that exposure to low doses relevant for humans and wildlife at critical time points in development can result in profound effects on both endocrine pathways and (neuro)development.     

Zn isotope study of atmospheric emissions and dry depositions within a 5 km radius of a Pb–Zn refinery

The present paper examines the use of zinc isotopes as tracers of atmospheric sources and focuses on the potential fractionation of Zn isotopes through anthropogenic processes. In order to do so, Zn isotopic ratios are measured in enriched ores and airborne particles associated with pyrometallurgical activities of one of the major Pb–Zn refineries in France. Supporting the isotopic investigation, this paper also compares morphological and chemical characteristics of Zn particles collected on dry deposition plates (“environmental samples”) placed within a 5 km radius of the smelter, with those of Zn particles collected inside the plant (“process samples”), i.e. dust collected from the main exhaust system of the plant. To ensure a constant isotopic “supply”, the refinery processed a specific set of ores during the sampling campaigns, as agreed with the executive staff of the plant. Enriched ores and dust produced by the successive Zn extraction steps show strong isotope fractionation (from ?0.66 to +0.22‰) mainly related to evaporation processes within the blast furnaces. Dust from the main chimney displays a δ⁶⁶Zn value of ?0.67‰. Application of the Rayleigh equation to evaluate the fractionation factor associated with the Zn vapor produced after a free evaporation gives a range of α_ore/vapor from 1.0004 to 1.0008. The dry deposits, collected on plates downwind of the refinery, display δ⁶⁶Zn variations of up to +0.7‰. However, it is to be noted that between 190 and 1250 m from the main chimney of the refinery, the dry deposits show a high level of large (>10 μm) Zn, S, Fe and O bearing aggregates characterized by positive δ⁶⁶Zn values (+0.02 to +0.19‰). These airborne particles probably derive from the re-suspension of slag heaps and local emissions from the working-units. In contrast, from 1720 to 4560 m, the dry deposits are comprised of small (PM10) particles, including spherical Zn-bearing aggregates, showing negative δ⁶⁶Zn values (?0.52 to ?0.02‰). Our results suggest that the source of the distal dry fallouts is the main chimney plume, whose light Zn isotopic signature they preserve. Based on Zn isotopic analysis in combination with morphological and chemical characteristics of airborne particles, the present study suggests the traceability of smelter dusts by Zn isotopes.     

Estrogenic and esterase-inhibiting potency in rainwater in relation to pesticide concentrations,sampling season and location

In a year-round monitoring program (1998), pesticide composition and toxic potency of the mix of pollutants present in rainwater were measured. The goal of the study was to relate atmospheric deposition of toxic potency and pesticide composition to each other and to sampling period and local agricultural activity. Rainwater was collected in 26 consecutive periods of 14 days in a background location (BACK) and in two locations representative for different agricultural practices, i.e. intensive greenhouse horticulture (HORT) and flower bulb culture (BULB). Samples were chemically analyzed for carbamate (CARB), organophosphate (OP) and organochlorine (OC) pesticides and metabolites. Esterase inhibiting potency of rainwater extracts was measured in a specially developed bio-assay with honeybee esterases and was expressed as an equivalent concentration of the model inhibitor dichlorvos. Estrogenic potency of the extracts was measured in the ER-CALUX reporter gene assay and was expressed as an equivalent concentration of estradiol. Multivariate principal component analysis (PCA) techniques proved to be valuable tools to analyze the numerous pesticide concentrations in relation to toxic potency, sampling location, and sampling season. Pesticide composition in rainwater depended much more on sampling season than on sampling location, but differences between and were mainly attributed to local differences in agricultural practice. On average, the esterase inhibiting potency exceeded the maximum permissible concentration set for dichlorvos in The Netherlands, and was significantly higher in than in and . Esterase inhibition correlated significantly with OP and CARB concentrations, as expected given the working mechanism of these insecticides. The estrogenic potency incidentally exceeded NOEC levels reported for aquatic organisms and was highest in . Although estrogenic potency of rainwater correlated with OC concentrations, the ER-CALUX responses could not be attributed to any particular pesticides. Besides, the contribution of non-analyzed xeno-estrogens as alkylphenol(-ethoxylates) and bisphenol-A to the estrogenic potency of rainwater could not be excluded. Further research should focus on the chemical identification of estrogenic compounds in rainwater. In addition, more attention should be given to the ecological consequences of atmospheric deposition of individual pesticides and of total toxic potencies that regularly exceed environmental criteria for Dutch surface waters and/or toxic threshold values for aquatic organisms.     

To reduce and not to reduce resource consumption? That is two questions

Recent research shows that because they rely on separate goals, cognitions about not performing a behaviour are not simple opposites of cognitions about performing the same behaviour. Using this perspective, two studies (N = 758 & N = 104) examined the psycho-social determinants of reduction in resource consumption. Results showed that goals associated with reducing versus not reducing resource consumption were not simple opposites (Study 1). Additionally, the discriminant validity of the Theory of Planned Behaviour constructs associated with reducing versus not reducing resource consumption was demonstrated (Study 1 & 2). Moreover, results revealed the incremental validity of both Intentions (to reduce and to not reduce resource consumption) for predicting a series of behaviours (Study 1 & 2). Finally, results indicated a mediation role for the importance of ecological dimensions on the effect of both Intentions on a mock TV choice and a mediation role for the importance of non ecological dimensions on the effect of Intention of not reducing on the same TV choice. Discussion is organized around the consequences, at both theoretical and applied levels, of considering separate motivational systems for reducing and not reducing resource consumption.     

The anthropogenic atmospheric elements fraction: A new interpretation of elemental deposits on tree barks

The superficial deposit on the bark surface of several trees (mainly Fraxinus excelsior L.) was sampled in the experimental station of the university campus in Grenoble (France). Its composition was studied by scanning electron microscopy–energy dispersive X-ray emission (SEM–EDX) and, after digestion, by inductively coupled plasma-mass spectrometry (ICP-MS). The deposit was composed of 81.3% ± 7.4 organic matter, 9.4% ± 4.9 of geogenic minerals issued from the atmosphere (atmospheric geogenic fraction: AGF) and 9.3% ± 2.7 of a mixture of elements which was called anthropogenic atmospheric elements fraction (AAEF). The SEM–EDX analysis showed the presence of particles of geogenic compounds such as different types of silicates, phosphates, carbonates, sulphates, oxides and also particles of metals such as iron or of alloys of Fe–Zn, Fe–Ni, Ni–Cr and Ca sulphates or phosphates. Typical spheres of “fly ashes” composed of pure iron or Al-silicates were detected. Using the SEM–EDX analysis of the deposit and the average local soil composition, an empiric formula for the AGF (without polluting elements) was chosen, which presented a clear analogy with the global formula of the upper continental crust. In the same way, a formula for the pure organic matter fraction was chosen. Withdrawing the elements corresponding to these two fractions allows a tentative estimation of the content of the AAEF which was supposed to better represent the elemental anthropogenic contamination issued from the atmosphere. In the station, most of Sb, Cd, Sn, Pb, Cu, V and Zn were found in the AAEF. This AAEF composition was compared to that of the deposit in a highway tunnel where Pb and Cu were at a very high level. The meaning and the limits of the AAEF concept were critically discussed.     

Uptake of cadmium by the invasive perennial weeds Ranunculus repens and Geranium robertianum under laboratory conditions

The objective of this study was to compare the accumulation and partitioning of cadmium (Cd) in a fibrous versus a tap root weed, Ranunculus repens and Geranium robertianum respectively. To meet this objective, we compared the accumulation by and the partitioning of Cd in R repens versus G. robertianum grown in soils spiked with 0.015 grams of Cd for a period of three weeks. The rate of Cd uptake was also compared by following the fate of 109Cd within the root, stem and leaf of the two weeds. Prior to Cd exposure, leaf and stem of control R. repens contained significantly greater amounts of Cd as compared to G. robertianum, whereas Cd concentrations in roots of the control plants for the two species were not significantly different (p > 0.05, student's t-test). Post Cd exposure the two species contained similar amounts of Cd in leaf and stem, however, roots of R. repens contained almost two-fold the amounts of Cd as compared to G. robertianum. Comparison of k (h(-1), rate of 109Cd uptake) for stem, leaf and root of the two species indicated that G. robertianum accumulated 109Cd over the first 24-48 h at a faster rate as compared to R. repens. For both species and all three organs, maximum accumulation of 109Cd occurred within the first 24-48 h. Our findings indicate that the fate of Cd within these two species is quite different with the fibrous root of R. repens serving to accumulate and store Cd whereas in G. robertianum, Cd is rapidly taken up and tends to be accumulated within its leaf.     

Host selection by a kleptobiotic spider

Why do kleptobiotic spiders of the genus Argyrodes seem to be associated with spiders of the genus Nephila worldwide? Observations following introduction of experimental insect prey of different sizes and weights on to host webs revealed that: (1) small prey are more effectively retained on the web of Nephila clavipes than on the web of another common host, Leucauge venusta. (2) N. clavipes did not consume small prey that accumulated on the web whereas larger, heavier prey were enveloped and stored. (3) We observed clear partitioning of prey items between N. clavipes and Argyrodes spp.; diet selection by Argyrodes did not overlap with that of N. clavipes but closely overlapped with that of L. venusta. (4) L. venusta responds very quickly to prey impact whereas N. clavipes is slower, offering a temporal window of opportunity for Argyrodes foraging. (5) The ability of L. venusta to detect and respond to small items also means that it acts aggressively to Argyrodes spp., whereas N. clavipes does not. Consequently, food-acquisition behaviours of Argyrodes were clearly less risky with N. clavipes compared with L. venusta. We conclude that when a kleptobiotic organism has a choice of various host species, it will opt for the least risky host that presents the highest rate of availability of food items. The fact that Nephila species present such characteristics explains the worldwide association with Argyrodes kleptobiotic spiders.     

Aquatic and terrestrial ecotoxicology considering the soil:water continuum in the Anthropocene context

Environmental Science and Pollution Research -