用于水中多环芳烃被动采样的聚合物厚度和材料的选择：哪个更有力地影响采样器性能？

本文使用3种单相聚合物制作用于多环芳烃被动采样的装置,这3种聚合物分别为聚甲醛(POM)、硅橡胶(SR)和聚乙烯(PE),通过室内试验测定了它们的分配系数和POM的扩散系数以及验证了动态积累模型。此外,在野外现场对每种装置的性能进行了评估。基于已开发模型的支持,讨论了使用不同材料和聚合物厚度的装置性能。结果表明,采样器性能,比如浓度平均周期的长短和多环芳烃的采集容量,都广受所选材料的影响。采样器的厚度也会对装置的性能造成影响,但程度很小。选择合适的聚合物和/或厚度可以使采样器更有适用于快速平衡或动态积累,以及促进膜或水边界层对动态积累的控制。此外,利用膜技术控制或平衡的化合物能够更精确的被量化,因为它们不需要利用参比法(PRC)来校正。然而,当富集浓度达到平衡后,采样器中的平均浓度就不能准备测量化合物浓度,而由膜控制的采样装置通过动态累积的方式能够提供不需要PRC校正的平均浓度;随着膜传质阻力的提高,采样器的检测限也得到提高。
精选自Angel Belles, Claire Alary, Yannick Mamindy-Pajany.Thickness and material selection of polymeric passive samplers for polycyclic aromatic hydrocarbons in water: which more strongly affects sampler properties?. Environmental Toxicology and Chemistry: Volume 35, Issue 7, pages 1708–1717, July 2016. DOI: 10.1002/etc.3326
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3326/full
     

A multi-event model to study stage-dependent dispersal in radio-collared hares: when hunting promotes costly transience

Behavioral ecologists have often assumed that dispersal is costly mainly because of unfamiliarity with traversed habitats during dispersal and energy costs of the movement per se; thus, dispersers that have successfully settled should experience survival rates comparable to those of philopatric individuals. In this paper, we tested that hypothesis using 152 radio-collared European hares in a harvested population. We developed a multi-event capture recapture model, combining telemetry data and recoveries and separately modeling the foray probability, the settlement probability, and the permanent dispersal probability. The parameterization introduced here raises the possibility of separately testing effects on survival and dispersal probabilities at each stage of dispersal (departure, transience, and settlement). In accordance with our expectations, we reveal that dispersers incur higher mortality risks during transience and the early settlement period than philopatric individuals or settled dispersers. We also found that dispersers suffer from higher risks of being shot. Those results illustrate that unfamiliarity with the habitat during transience makes dispersal costly and that settled dispersers may enjoy survival rates comparable to those of philopatric individuals. Surprisingly, we also found that individuals have a higher probability of foraying during the hunting season. We suggest that hunting and related disturbances increase dispersal costs both by increasing mortality risk during transience and (perhaps) by increasing movement rates. We emphasize the need to take human pressures into account as factors that may drive the demographics of movements in populations.     

Misspecification of within-area exposure distribution in ecological Poisson models

Ecological studies enable investigation of geographic variations in exposure to environmental variables, across groups, in relation to health outcomes measured on a geographic scale. Such studies are subject to ecological biases, including pure specification bias which arises when a nonlinear individual exposure-risk model is assumed to apply at the area level. Introduction of the within-area variance of exposure should induce a marked reduction in this source of ecological bias. Assuming several measurements per area of exposure and no confounding risk factors, we study the model including the within-area exposure variability when Gaussian within-area exposure distribution is assumed. The robustness is assessed when the within-area exposure distribution is misspecified. Two underlying exposure distributions are studied: the Gamma distribution and an unimodal mixture of two Gaussian distributions. In case of strong ecological association, this model can reduce the bias and improve the precision of the individual parameter estimates when the within-area exposure means and variances are correlated. These different models are applied to analyze the ecological association between radon concentration and childhood acute leukemia in France.

Fate of 17β-estradiol in terrestrial model ecosystems amended with contaminated composted biosolids

Biosolids spread onto agricultural soils are potential sources of steroidal hormones that are able to adversely affect the soil ecosystem. Here we studied the fate of the [4-¹⁴C]-17-β-estradiol hormone in laboratory experiments. First, our results show that only 2.9% of the hormone was mineralized in the soil from a French vineyard. By contrast, the mineralization increased to 7.1% when the hormone was provided in composted biosolids. Second, we found that only a minor part of the estradiol-derived ¹⁴C was mobile and partly transferred to soil leachates. Indeed, the hormone was mainly stabilized in the soil as non-extractable residues. Overall, our findings show that estradiol undergoes two main processes, complete degradation and stabilisation. We therefore conclude that the environmental risk of hormones provided to the soil through composted biosolids is negligible under the conditions of our experiments.     

Impact of UV-irradiation on the formation of odorous chloroaldimines in drinking water

In order to explain some of the possible origins of an odor episode which took place in a drinking water supply in the region of Paris (France), the impact of disinfection on the formation of odorous by-products was investigated. We have previously established that very odorous and stable chloroaldimines are formed during amino acid chlorination in conditions relevant to those of drinking water treatment. As chlorination is preceded by a UV-irradiation step, we examined here the impact of this irradiation on the formation of chloroaldimines. Irradiation (30 m W cm(-2)) of various amino acids (glycine, valine, phenylalanine) and peptides (Phe-Gly-Gly-Phe, Phe-Ala) led to a degradation of the compounds but it was negligible at the doses applied in drinking water supplies. As peptides were concerned, contrary to what we previously expected, the degradation did not involve the peptidic bond breaking: irradiation induces therefore no increase in the quantity of free amino acids, precursors of odorous chloroaldimines. However chlorination of peptides (Phe-Ala-Ala-Val, Phe-Gly-Gly-Phe and Ala-Phe) showed that chloroaldimines are also probably formed during combined amino acids chlorination.     

Sediment quality in Rio Guadiamar (SW, Spain) after a tailing dam collapse: contamination, toxicity and bioavailability

An integrated assessment of sediment quality in the Guadiamar River after a mining spill was conducted. The concentration of different metals and other conventional parameters were measured in sediments located along the river. Four sediment toxicity tests (Hyalella azteca 28-day survival and growth test; Chironomus riparius 10-day survival and growth test; Hexagenia spp. 21-day survival and growth test; and Tubifex tubifex 28-day reproduction and survival test) were carried out to determine the effects associated with the accidental spill. The geochemical fractions of 6 metals (Fe, Mn, Zn, Cu, Pb, and Cd) were determined to establish the bioavailability of the metals. The relationship found in the concentrations of metals associated with the mobile fractions of the sediments in the sites studied is similar to the toxic mud from tailing pond and confirms that the toxic effects are associated with the metals Zn and Cd originating from the spill.     

A geochemical study of overbank sediments in an urban area (Madrid,Spain)

Overbank and stream sediments have been studied in the Community of Madrid. Four vertical profiles have been sampled corresponding to Guadarrama, Jarama, and finally Manzanares River, where two profiles have been studied upstream (El Pardo profile) and downstream (Rivas profile) Madrid city. Sieved samples (<63 µm) were subjected to total (ICP-MS/ICP-OES and INAA) and partial analysis (ICP-MS). AMS radiocarbon dating techniques revealed a young age (170 ± 40 years BP) at 2.40–2.65 m depth for Rivas profile. It has not been possible to detect pristine or pre-industrial overbank sediments, since in the rest of the studied profiles, anthropogenic wastes were found even in the lower levels. Three main sources of sediment have been detected in the area. Granitic and arkosic geology, located in the northern part of Madrid (U, Th, W, K, Na, or rare earth elements); clays located in the southeast of Madrid (Ni, Cr, or V), and finally an anthropogenic source has been identified (Au, Ag, Pb, Zn, or Sb) in Rivas profile. The influence of the anthropogenic activity has been established based on the contents distribution of contaminant elements in the profile. This can be associated to the growth of industrial activities and population in the city of Madrid during the last decades. The comparison of the profiles by a k-means cluster analysis showed some similarities for these samples that could have analogous sources (anthropogenic and geological).     

Estimating the safety performance of urban intersections in Lisbon,Portugal

According to official statistics, a large percentage of crashes in Portugal are reported on urban roads. For instance, from 2004 to 2007, about 70% of all injury accidents and 43% of the fatalities occurred inside urban agglomerations. This important safety problem has also been observed on the urban network of Lisbon. Understanding this significant problem, the Government of the Portuguese Republic via its research grant agency – The Foundation for Science and Technology – funded a project whose primary objective consists of developing tools that would help estimating the safety performance of various components of the urban highway system in Lisbon. This paper documents one component of the safety tools that were developed and describes the steps that were taken to develop predictive models for estimating the safety performance of signalized and unsignalized intersections of Lisbon. Several crash predictive models were developed using the Poisson-gamma modeling framework. Two types of models were estimated: flow-only and models with covariates. They were estimated using crash and other related data collected at 44 three-legged and 50 four-legged intersections for the years 2004–2007, inclusively. It was found that some highway geometric design characteristics were associated with the crashes occurring at urban three- and four-legged intersections in Lisbon.     

Kraft mill residues effects on Monterey pine growth and soil microbial activity

The production of bleached Kraft pulp generates inorganic and organic residues that are usually deposited on the soil surface or land-filled. Studies conducted to address the impact of these wastes on the environment are scarce. In this work, Monterey pine (Pinus radiata D. Don), an important tree for pulping, was evaluated for germination and development under greenhouse conditions in forest soils exposed to solid residues of the cellulose industry using the Kraft process. Soils exposed to 10 to 60% ashes, 10 to 70% fly ashes, or 10 to 30% dregs allowed substantial seed germination and seedling growth. In contrast, soils exposed to low proportions of brown rejects, grits, or a mixture of all these residues were detrimental for germination, plant growth, or both. The strongest negative effect (no germination) was observed with as low as 10% grits. The changes in pH and/or water content caused by solid wastes did not correlate with detrimental effects observed in various soil-residue combinations. No significant changes in the microbial community of soils exposed to these solid residues were observed by determination of culturable counts, or by terminal-restriction fragment length polymorphism analysis of the microbial community DNA. The presence of organic residues did not affect the ability of the soil microbial community to remove typical pulp bleaching chloroaromatics. However, inorganic wastes strongly decreased the removal of such compounds.     

Heavy metal bioavailability and effects: II. Histopathology-bioaccumulation relationships caused by mining activities in the Gulf of Cádiz (SW, Spain)

The relationship between bioaccumulation of heavy metals (Zn, Cd, Pb and Cu) and histological lesions in different tissues of organisms is assessed in three different areas located in the southwest of Spain in the Gulf of Cádiz (Ría of Huelva, Guadalquivir estuary and Bay of Cádiz) affected and non-affected by mining activities. Data included in these relationships were obtained along the years 2000 and 2001 to address the impact of the Aznalcóllar mining spill on the Guadalquivir estuary. The bioaccumulation and the histological lesions measured in this seasonal study in the Gudalquivir estuary were linked to derive tissue quality guidelines (TQGs) by means of a multivariate analysis approach (MAA). Sediments collected in the same areas of study were used to expose organisms during the survey carried out in autumn 2001 and to address the relationship between bioaccumulation and histological lesions under laboratory conditions and related to chemicals bound to sediments. Lesions show that the organisms collected in the ría of Huelva and exposed to their sediments were severe, intermediate in the Guadalquivir estuary and absent in the Bay of Cádiz. Results show that the Guadalquivir estuary trends to recover its initial status quo previous to the mining spill. The link between chemical concentration and the lesions measured in the same tissues using MAA permits to derive tissue quality guidelines for two organisms, oysters (Crassostrea angulata) and clams (Scrobicularia plana) collected in the Guadalquivir estuary and associated with the heavy metals from the mining spill (Zn and Cd). The TQG values expressed as concentrations (mgkg-1--dry weight) not associated with biological effects are for oysters, Zn, 8603, Cd, 3.42; and for clams Zn, 800, Cd, 2.6.