The combined use of chemical and biochemical markers to assess water quality along the Ebro River

Carp (Cyprinus carpio) and barbel (Barbus graellsii) were collected from five sites along the Ebro River. The study was designed to assess levels of persistent organic pollutants and metals bioaccumulated by fish, and some biochemical responses (cytochrome P450 system, phase II activities, and metallothioneins) against those pollutants. The highest levels of PCBs and DDTs were detected in carp from industrialised areas, which also showed high levels of mercury and cadmium in the liver, and high levels of nonylphenol in bile. Significant alterations in some biochemical markers were observed and associated to combined exposure to pollutants. The activity 7-ethoxyresorufin O-deethylase ranged from 69 pmol/min/mg protein in carp from the reference site to 415 pmol/min/mg protein in those from polluted sites. Carp from the Ebro Delta, an agricultural area, had depressed acetylcholinesterase in muscle tissue. Metallothionein concentrations were positively correlated with copper residues, but no significant differences among sampling points were observed.     

Tessaria absinthioides: a possible bio‐monitor for Cd,Pb, and Cu,in the middle and lower basin of the loa river,North Chile

Some ecotoxic metals such as Cd, Pb, and Cu in Tessaria absinthioides were quantified to study its possible use as a bio‐indicator and/or bio‐monitor of these metals. This plant was chosen for its abundance in the area under study, along Chile and even in southern Latin America. For Cd, Pb, and Cu in all three parts of the plant (leaves, stems and roots) a different concentration pattern in each sampling areas was observed. In sampling areas Coya Sur and La Cascada copper and cadmium concentration decrease in order: leaves > roots > stems. In samples collected in Xalquincha the lowest concentrations of Cd and Pb were observed in stems. A maximum of cadmium concentration (9ug/gd.w. in leaves) was found in samples from La Cascada, a inflow to river Loa in Calama. High concentrations of lead were found in roots and leaves. Collected data demonstrate that the main pathway for cadmium is from ground water via roots into the plant. Some data obtained for lead and copper indicate that the influence of dust particles adsorbed on leaves and stems can be higher than uptake from ground water.     

Zinc distribution in soils amended with different kinds of sewage sludge

Sewage sludge (SS) can be applied to cropland to supply and recycle nutrients and organic carbon. Potentially toxic elements in the sludge, however, are of environmental concern. This study evaluates the changes in chemical speciation of Zn in three representative pristine soils of the Pampas Region, Argentina, measured with sequential extraction over a one-year period. Pure SS or SS containing 30% (DM) of its own incineration ash (AS) was applied to the soils at an application rate of 150Mgha(-1). Zn was sequentially fractionated into exchangeable, organically bound, inorganic and residual fractions. The application of the SS and AS amendments significantly increased Zn concentration in all soil fractions at each sampling date. At day 1, Zn was mainly found in the residual fraction. A year after the application of the amendments, redistribution towards the inorganic fraction was observed (41-76% of total Zn content). Zn found in exchangeable and inorganic fractions depended on soil pH rather than on the type of soil used. A negative and significant correlation was found between exchangeable Zn concentrations and soil pH (r=0.94), and a positive and significant correlation between inorganic Zn concentrations and soil pH (r=0.92). For each amended soil and sampling date, no significant differences were observed between SS or AS treatments for the exchangeable fraction. Moreover, the use of AS did not cause significant differences in Zn concentration in the other soil fractions compared to SS. Based on these results, land spreading of AS may be similar to SS diaposal in terms of Zn mobility.     

Using and comparing two nonparametric methods (CART and MARS) to model the potential distribution of gullies

Gully erosion represents an important soil degradation process in rangelands. In order to take preventive or control measures and to reduce its environmental damages and economical costs it is useful to localize the points in the landscape where gullying takes place and to determine the importance of the different factors involved. The study is carried out in Extremadura, southwest Spain. The main objectives of this work are: (a) comparing two nonparametric schemes to model the potential distribution of gullies, (b) evaluating the importance of the different factors involved in gullying processes, (c) analyzing the role of prevalence in the success of the model and finally, (d) implementing and mapping the results with the help of a Geographical Information System (GIS). Two methods were used to model the response of a dependent variable (gullying) from a set of independent variables: Classification And Regression Trees (CART) and Multivariate Adaptive Regression Splines (MARS). Three different datasets were used; the first one for constructing the model (training dataset) and the others for validating the model (external datasets). These datasets are formed by a target variable (presence or absence of gullies) and a set of independent variables. The dependent variable was obtained by mapping the locations of gullies with the help of a GPS and high resolution aerial ortophotographs. A set of 32 independent variables reflecting topography, lithology, soil type, climate, land use and vegetation cover of each area were used. The performance of the models was evaluated using a non-dependent threshold method: the Receiver Operating Characteristic (ROC) curve. The results showed a better performance of MARS for predicting gullying with areas under the ROC curve of 0.98 and 0.97 for the validation datasets, while CART presented values of 0.96 and 0.66.     

Cross-sectional biomonitoring study of pesticide exposures in Queensland,Australia, using pooled urine samples

A range of pesticides are available in Australia for use in agricultural and domestic settings to control pests, including organophosphate and pyrethroid insecticides, herbicides, and insect repellents, such as N,N-diethyl-meta-toluamide (DEET). The aim of this study was to provide a cost-effective preliminary assessment of background exposure to a range of pesticides among a convenience sample of Australian residents. De-identified urine specimens stratified by age and sex were obtained from a community-based pathology laboratory and pooled (n = 24 pools of 100 specimens). Concentrations of urinary pesticide biomarkers were quantified using solid-phase extraction coupled with isotope dilution high-performance liquid chromatography–tandem mass spectrometry. Geometric mean biomarker concentrations ranged from <0.1 to 36.8 ng/mL for organophosphate insecticides, <0.1 to 5.5 ng/mL for pyrethroid insecticides, and <0.1 to 8.51 ng/mL for all other biomarkers with the exception of the DEET metabolite 3-diethylcarbamoyl benzoic acid (4.23 to 850 ng/mL). We observed no association between age and concentration for most biomarkers measured but noted a “U-shaped” trend for five organophosphate metabolites, with the highest concentrations observed in the youngest and oldest age strata, perhaps related to age-specific differences in behavior or physiology. The fact that concentrations of specific and non-specific metabolites of the organophosphate insecticide chlorpyrifos were higher than reported in USA and Canada may relate to differences in registered applications among countries. Additional biomonitoring programs of the general population and focusing on vulnerable populations would improve the exposure assessment and the monitoring of temporal exposure trends as usage patterns of pesticide products in Australia change over time.     

Prediction of near-surface soil moisture at large scale by digital terrain modeling and neural networks

The capability of Artificial Neural Network models to forecast near-surface soil moisture at fine spatial scale resolution has been tested for a 99.5 ha watershed located in SW Spain using several easy to achieve digital models of topographic and land cover variables as inputs and a series of soil moisture measurements as training data set. The study methods were designed in order to determining the potentials of the neural network model as a tool to gain insight into soil moisture distribution factors and also in order to optimize the data sampling scheme finding the optimum size of the training data set. Results suggest the efficiency of the methods in forecasting soil moisture, as a tool to assess the optimum number of field samples, and the importance of the variables selected in explaining the final map obtained.     

Evidence of endocrine alteration in the red mullet, Mullus barbatus from the NW Mediterranean

Red mullet (Mullus barbatus) were collected from different sampling sites (NW Mediterranean) in spring and autumn, with the aim of assessing potential alterations of the endocrine system. Alkylphenols were measured in fish bile as an indicator of estrogenic exposure. Key enzymatic activities involved in both synthesis (ovarian 17beta-hydroxysteroid dehydrogenases and P450 aromatase) and metabolism of steroids were assessed together with histological alterations of the gonads. During the spring sampling, delayed gamete maturation, intersexuality, fibrosis, and depressed ovarian P450 aromatase activity were observed in organisms from the most polluted sites. During the autumn sampling, those effects were less evident, indicating that fish might be more susceptible to endocrine disrupting chemicals during the reproductive period. Nonetheless, enhanced glucuronidation of testosterone and estradiol was observed. Overall, this work provides first evidences of significant alterations in the endocrine system of red mullet from highly impacted areas in the NW Mediterranean.     

Adaptive Management, Monitoring, and the Ecological Sustainability of a Thermal-Polluted Water Ecosystem: A Case in Sw Spain

The construction of the Almaraz nuclear power plant in Spain in the 1970s posed interesting environmental problems concerning the construction of a cooling reservoir (Arrocampo reservoir) to cool the steam condensers and the consequent heating of the reservoirs water. The socio-political context forced decision makers to set up a project for the monitoring and management of the environmental impacts derived from the construction and operation of the power plant. Numerous scientific and technical specialists collaborated with the representatives of social groups towards two goals: the improvement of the biodiversity and of the efficiency of the cooling system. These goals involved the monitoring and managing of the system with respect to different biological aspects, mainly limnology, ichthyology, avian fauna and vegetation. The management plan yielded numerous results. The control of the water eutrophy is one of the most important due to its repercussion on the rest of the ecosystem, especially the fish fauna. The development of the shore vegetation slowly increased the patchwork nature of the reservoir, leading to a greater diversity of the avian species. This paper describes the monitoring and management of the Arrocampo ecosystem, the condition before and after the construction of the reservoir and the results obtained concerning some biological communities.     

Effects of exposure to ED contaminants (TPT-Cl and Fenarimol) on crinoid echinoderms: comparative analysis of regenerative development and correlated steroid levels

Regenerative phenomena reproduce developmental processes in adult organisms and are regulated by neuro-endocrine mechanisms. They can therefore provide sensitive tests for monitoring the effects of exposure to endocrine disrupter contaminants (EDs) which can be bioaccumulated by the organisms causing dysfunctions in steroid hormone metabolism and activities and affecting reproduction and development. Echinoderms are prime candidates for this new ecotoxicological approach, since (1) they offer unique models to study physiological regenerative processes and (2) in echinoderms vertebrate-type steroids can be synthesized and used as terminal hormones along the neuro-endocrine cascades regulating reproductive, growth and developmental processes. We are currently exploring the effects on the regenerative potential of echinoderms of different classes of compounds that are well known to have ED activity. The present paper focuses on the possible effects of well-known compounds with suspected androgenic activity such as TPT-Cl (Triphenyltin-chloride) and Fenarimol [(±)-2,4-dichloro-α-(pyrimidin-5-yl) benzhydryl alcohol]. The selected test-species is the crinoid Antedon mediterranea, a tractable and sensitive benthic filter-feeding species which represents a valuable experimental model for investigation on the regenerative process from the macroscopic to the molecular level. The present investigation employs an integrated approach which combines exposure experiments and biological analysis utilizing microscopy, immunocytochemistry and biochemistry. The experiments were carried out on experimentally induced arm regenerations in semistatic controlled conditions with exposure concentrations comparable to those of moderately polluted coastal zones. The bulk of results obtained so far provide indications of significant sublethal effects from exposure to TPT-Cl and Fenarimol and mechanisms of toxicity related to developmental physiology, which are associated with variations in steroid levels in the animal tissues. The results indicate that these two substances (1) affect growth and development by interfering with the same basic cellular mechanisms of regeneration, such as cell proliferation, migration and differentiation/dedifferentiation, which are possibly controlled by steroid hormones; and (2) can induce a number of significant modifications in the timing, modalities and pattern of arm regeneration, which may involve the activation of cell mechanisms related to steroid synthesis/metabolism. Physical and Chemical Impacts on Marine Organisms, a Bilateral Seminar Italy-Japan held in November 2004     

Amazon River dissolved load: temporal dynamics and annual budget from the Andes to the ocean

The aim of the present study is to estimate the export fluxes of major dissolved species at the scale of the Amazon basin, to identify the main parameters controlling their spatial distribution and to identify the role of discharge variability in the variability of the total dissolved solid (TDS) flux through the hydrological cycle. Data are compiled from the monthly hydrochemistry and daily discharge database of the “Programa Climatologico y Hidrologico de la Cuenca Amazonica de Bolivia” (PHICAB) and the HYBAM observatories from 34 stations distributed over the Amazon basin (for the 1983–1992 and 2000–2012 periods, respectively). This paper consists of a first global observation of the fluxes and temporal dynamics of each geomorphological domain of the Amazon basin. Based on mean interannual monthly flux calculations, we estimated that the Amazon basin delivered approximately 272?×?10⁶ t year^?1 (263–278) of TDS during the 2003–2012 period, which represents approximately 7 % of the continental inputs to the oceans. This flux is mainly made up by HCO₃, Ca and SiO₂, reflecting the preferential contributions of carbonate and silicate chemical weathering to the Amazon River Basin. The main tributaries contributing to the TDS flux are the Marañon and Ucayali Rivers (approximately 50 % of the TDS production over 14 % of the Amazon basin area) due to the weathering of carbonates and evaporites drained by their Andean tributaries. An Andes–sedimentary area–shield TDS flux (and specific flux) gradient is observed throughout the basin and is first explained by the TDS concentration contrast between these domains, rather than variability in runoff. This observation highlights that, under tropical context, the weathering flux repartition is primarily controlled by the geomorphological/geological setting and confirms that sedimentary areas are currently active in terms of the production of dissolved load. The log relationships of concentration vs discharge have been characterized over all the studied stations and for all elements. The analysis of the slope of the relationship within the selected contexts reveals that the variability in TDS flux is mainly controlled by the discharge variability throughout the hydrological year. At the outlet of the basin, a clockwise hysteresis is observed for TDS concentration and is mainly controlled by Ca and HCO₃ hysteresis, highlighting the need for a sampling strategy with a monthly frequency to accurately determine the TDS fluxes of the basin. The evaporite dissolution flux tends to be constant, whereas dissolved load fluxes released from other sources (silicate weathering, carbonate weathering, biological and/or atmospheric inputs) are mainly driven by variability in discharge. These results suggest that past and further climate variability had or will have a direct impact on the variability of dissolved fluxes in the Amazon. Further studies need to be performed to better understand the processes controlling the dynamics of weathering fluxes and their applicability to present-day concentration–discharge relationships at longer timescales.