Patterns of metal soil contamination and changes in terrestrial cryptogamic communities

Correlations between terricolous bryophyte- and lichen- vegetation and edaphic parameters (pH, organic matter, nitrogen, Carbon/nitrogen ratio, Cation Exchange Capacity, and Cd, Pb and Zn soil contents) of soils submitted to a gradient of metal contamination in northern France were performed using statistical analysis. Six classes can be distinguished according to the low-, intermediate- and high-trace metal levels respectively, leading to the conclusion that bryophyte- and lichen-groupings have a strong bioindicative value of the heavy metal pollution of soils.     

In situ bioassay chambers and procedures for assessment of sediment toxicity with Chironomus riparius

The purpose of this study was to develop an in situ sediment bioassay chamber and respective procedures, suitable for performing toxicity bioassays with benthic invertebrates, using the midge Chironomus riparius. It was also our objective to compare the responses obtained under controlled conditions (laboratory 10-day larval growth and survival test) with those obtained in situ. Clean sand and a formulated sediment were incorporated in the in situ bioassay, along with local sediments, as a way of minimizing natural variability due to physicochemical differences among sediments or due to interactions with indigenous organisms. Recovery of organisms was good (80-100% in the control and reference site), indicating that the developed chamber and protocol were suitable for exposing and retrieving C. riparius in situ. Results also showed differences between responses obtained with formulated and natural sediment in situ, as well as between laboratory and in situ.     

Pelagic crinoids (Roveacrinida, Crinoidea) discovered in the Neogene of Poland

Until recently, it has been assumed that pelagic crinoids, the roveacrinids (Roveacrinida, Crinoidea), became extinct during the Cretaceous-Paleogene boundary event. Recent finds of well-preserved roveacrinidal remains (brachials and radials) in the Danian (Early Paleogene) of Poland showed that they survived into the earliest Cenozoic. This group was thus characterized as a "dead clade walking". Here, we present fossil evidence that these pelagic crinoids survived in Poland until at least the Middle Miocene (Badenian, ca. 14?Myr ago)-more than 50?Myr after their supposed extinction. These Miocene roveacrinids constitute the first documented evidence of Roveacrinida in strata of Neogene age, thus prolonging the stratigraphic range of pelagic crinoids. This find characterizes the order as a "Lazarus taxon" rather than a "dead clade walking" group.     

A methodological proposal for the evaluation of farmer’s adaptation to climate variability, mainly due to drought in watersheds in Central America

The current study shows the process and the results of a methodology proposed to contribute with the issue of how to evaluate the adaptation to climate variability and future climate change. The proposed methodology consists of a standard to evaluate farmer’s adaptation to climate variability, mainly due to drought in watersheds in Central America; and was created with contributions from experts and professionals around this region. The phases for this process were: (1) literature review about the topic, (2) development of a preliminary standard, (3) expert interviews for the evaluation of this preliminary standard, (4) construction of a standard to evaluate the issue of adaptation to climate variability emphasizing drought through contributions from experts and their preliminary evaluations, (5) applicability test of this standard for the evaluation of climate variability under real conditions and (6) application of this standard through a case study in the Aguas Calientes river sub-watershed in Nicaragua, which permanently undergoes drought problems and climate variability. This standard has five main principles that go from the general, considering regional and national policies and institutionalism, to the specifics at the level of watersheds. In addition to those principles, the standard contains ten criteria, 26 indicators and 51 verifiers distributed among the main five principles. In the process for testing this standard in the Aguas Calientes river watershed in Nicaragua, the score for the general applicability to this standard was middle-level (score of 3 in a scale of 1 to 5), although, for the main principles of this standard, the score was four (high).     

Microstructures of Antarctic cidaroid spines: diversity of shapes and ectosymbiont attachments

The echinoderm endoskeleton, located in the connective layer of the tegument, is organized into a three-dimensional mesh, the stereom. Among echinoids, the cidaroids depart from this pattern, and the shaft of the spine lacks an epidermis. Thus, the spines lack antifouling protection, allowing ectosymbionts such as bryozoans and foraminiferans to attach. This raises a question about the adaptive role of the cortical layer of the stereom. This study examined the micro- and mesostructure of the spines of 11 cidaroid species collected in the Weddell Sea and Drake Passage, and the nature of their ectosymbiont attachments. Scanning electron microscopy was used to characterize the cortex surface and X-ray micro computed tomography (μCT) to describe the symbiont attachments. Spine microstructure features provide a useful taxonomic character for distinguishing among three species in the genus Ctenocidaris, and challenge a previous parasitic interpretation of cortical filaments on the spines of Rhynchocidaris triplopora. Ectosymbiont attachments were classified as Anchoring, Molding, Cementing, or Corroding. The study suggests that some microstructure features may be protective, keeping the ectosymbionts away from the cortex and loosely attached at intervals along the shaft of the spine, while other micro-structures facilitate attachment over considerable areas of the shaft. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The presence of females modulates the expression of a carotenoid-based sexual signal

Several environmental factors have been shown to shape the pattern of investment of carotenoids into the expression of sexual signals. Surprisingly, the impact of the social environment has been neglected. If a carotenoid-based sexual trait is used by females to choose a mate or by males to assess the quality of potential competitors for mates, males, in the presence of females, should upregulate expression of the trait. We tested this hypothesis in male zebra finches that were housed either with females or in a male-only social environment. Additionally, to investigate whether the social modulation of the expression of a sexual trait depends on the physiological need of carotenoids, we challenged half of the males with Escherichia coli lipopolysaccharide (LPS). We found that the social environment modulated the expression of bill color, with males kept in the presence of females harboring a redder bill at the end of the 3 weeks that the experiment lasted. Males injected with LPS showed duller bill color regardless of the presence of females, and social interactions with females result in upregulated bill color similarly for phosphate-buffered saline (PBS) and LPS males. Thus, social environment and immune activation had an additive effect on the expression of bill color. The effect of social environment on plasma carotenoids was less clear. Indeed, a first replicate of the entire experiment showed that both immune challenge and social context affected bill color, with a negative effect of immune challenge and a positive effect of the presence of females on circulating carotenoids. However, a second replicate of the experiment showed only a negative effect of the immune challenge. These results, therefore, suggest that the social environment can affect the expression of carotenoid-based sexual traits under both benign and carotenoid-demanding conditions. Whatever the signaling function of bill color (female mate choice or male–male competition for mates), the observed flexibility may be adaptive because the expression of the signal can be modulated depending on the expected rewards or costs associated with the presence or absence of females. Nevertheless, the mechanisms underlying such an effect are still unknown.     

Metals and emerging contaminants in groundwater and human health risk assessment

Environmental Science and Pollution Research - Groundwaters are normally consumed without previous treatment and therefore the monitoring of contaminants in order to guarantee its safety is...     

Proposal to optimize ecotoxicological evaluation of wastewater treated by conventional biological and ozonation processes

A mixture of urban and hospital effluents (50 % v/v) was evaluated for ecotoxicity with an advanced bioassay battery. Mixed effluents were tested before any treatment, after biological treatment alone, and after biological treatment followed by a tertiary ozonation (15 mg O₃/L). Laying a high value on the continuance of organisms’ fitness, essential to preserve a healthy receiving ecosystem, the main objective of this study was to combine normalized bioassays with newly developed in vivo and in vitro tests in order to assess alteration of embryo development, growth and reproduction, as well as genotoxic effects in aquatic organisms exposed to complex wastewater effluents. Comparison of the bioassays sensitivity was considered. Contrary to the lack of toxicity observed with normalized ecotoxicity tests, endpoints measured on zebrafish embryos such as developmental abnormalities and genotoxicity demonstrated a residual toxicity in wastewater both after a biological treatment followed or not by a tertiary O₃ treatment. However, the ozonation step allowed to alleviate the residual endocrine disrupting potential measure in the biologically treated effluent. This study shows that normalized bioassays are not sensitive enough for the ecotoxicological evaluation of wastewaters and that there is a great need for the development of suitable sensitive bioassays in order to characterize properly the possible residual toxicity of treated effluents.     

Health risks of environmental exposure to metals and herbicides in the Pardo River,Brazil

Mixture of metals and herbicides in rivers may pose relevant risks for the health of surrounding communities. Humans may be exposed to river pollution through intake of contaminated water and fish, as well as irrigated agricultural products. The aim of this study was to assess the human health risks of environmental exposure to metals and herbicides through water and fish intake in the Pardo River. Metals (Al, As, Be, Cd, Cr, Cu, Pb, Mn, Hg, Ni, Tl, Sn, V, and Zn) were analyzed in river water and in edible fish. Herbicides (ametryn, atrazine, diuron, hexazinone, simazine, and tebuthiuron) were analyzed in river water. Seasonal variances were also studied. Aluminum, Cd, Cu, Mn, Pb, and Zn levels in river water were higher than the USEPA benchmarks. Non-carcinogenic risks due to pollutants mixture exposure were above the limit, and carcinogenic risks of As exposure were >10^?6 in the sampling points during the rainy season. Metal levels in fish were lower than the Brazilian legislation and do not pose a threat to public health. Herbicides were detected in four sampling points, with atrazine concentrations (range 0.16–0.32 μg/L) below the Brazilian standard (2.0 μg/L), but above the European Union standard (0.1 μg/L). Considering the water supply needs of cities located in the Pardo River Basin and the persistence of metals and herbicides, the present study indicated that there was a seasonal influence on non-carcinogenic and carcinogenic risks to human health, especially in the rainy season. Studies for water treatment plants implantation should consider the risks of exposure to persistent substances, in order to protect the population.