Trace elements in muscle of three fish species from Todos os Santos Bay,Bahia State,Brazil

In this study, an analysis was performed on the concentrations of the trace elements Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn in muscle of two carnivorous and one planktivorous fish species collected at Todos os Santos Bay (BTS). The accumulation order of the trace elements in Lutjanus analis was Al >Zn >Fe >Cr >Ba >Ni. In Cetengraulis edentulus, the order was Al >Fe >Zn >Cr >Ni >Mn >As. In the species Diapterus rhombeus, the order was Al >Fe >Zn >Cr >Ni >Mn >Cd. To determine the risk related to the consumption of fish, toxicity guidelines were used as standard references. It was observed that the species C. edentulus contained concentrations of As exceeding WHO limits, but these concentrations were acceptable according to the Agência Nacional de Vigilância Sanitária (ANVISA) guidelines. Cd levels were found only in D. rhombeus and in low concentrations according to the determinations of WHO and ANVISA. Pb levels were not detected in any of the three fish species. The analyzed elements did not differ statistically according to the species and feeding habits. The results point to possible risks of human contamination by As related to the consumption of the fish species C. edentulus from the BTS.     

2,4-dichlorophenoxyacetic acid (2,4-D) micropollutant herbicide removing from water using granular and powdered activated carbons: a comparison applied for water treatment and health safety

Abstract

Activated carbons are well-known porous materials as an effective adsorbent used for the removal of emerging contaminants, such as herbicides, which are increasingly present in water bodies. Most water treatment plants, specially in Brazil, are unable to completely remove such contaminants by the conventional process and advanced treatment using activated carbons is required. The aim of this paper was to verify the influence of the activated carbons granulometry and specific surface area on the 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide removal efficiency using distilled-deionized water and filtered water collected from a conventional Water Treatment Plant. Commercial activated carbons samples used in this work were obtained from two different manufacturers. Activated carbons were analyzed by the specific surface area, pore size and volume distribution, nuclear magnetic resonance, infrared and x-ray spectroscopy, moisture, volatile matter and ash contents. Batch adsorption isotherms experiments were used and performed by Langmuir and Freundlich models. Granular and powdered activated carbons removed over 99% of 2,4-D in distilled water and near to 99% using filtered water. The activated carbons evaluated in this work presented high performance and played a key role in water treatment by removing 2,4-D herbicide, ensuring the protection of human health and the ecosystem.     

State-specific detection probabilities and disease prevalence.

Investigations of disease dynamics in wild animal populations often use estimated prevalence or incidence as a measure of true disease frequency. Such indices, almost always based solely on raw counts of infected and uninfected individuals, are often used as the basis for analysis of temporal and spatial dynamics of diseases. Generally, such studies do not account for potential differences in observer detection probabilities of host individuals stratified by biotic and/or abiotic factors. We demonstrate the potential effects of heterogeneity in state-specific detection probabilities on estimated disease prevalence using mark-recapture data from previous work in a House Finch (Carpodacus mexicanus) and Mycoplasma gallisepticum system. In this system, detection probabilities of uninfected finches were generally higher than infected individuals. We show that the magnitude and seasonal pattern of variation in estimated prevalence, corrected for differences in detection probabilities, differed markedly from uncorrected (apparent) prevalence. When the detection probability of uninfected individuals is higher than infected individuals (as in our study), apparent prevalence is negatively biased, and vice versa. In situations where state-specific detection probabilities strongly interact over time, we show that the magnitude and pattern of apparent prevalence can change dramatically; in such cases, observed variations in prevalence may be completely spurious artifacts of variation in detection probability, rather than changes in underlying disease dynamics. Accounting for differential detection probabilities in estimates of disease frequency removes a potentially confounding factor in studies seeking to identify biotic and/or abiotic drivers of disease dynamics. Given that detection probabilities of different groups of individuals are likely to change temporally and spatially in most field studies, our results underscore the importance of estimating and incorporating detection probabilities in estimated disease prevalence (specifically), and more generally, any ecological index used to estimate some parameter of interest. While a mark-recapture approach makes it possible to estimate detection probabilities, it is not always practical, especially at large scales. We discuss several alternative approaches and categorize the assumptions under which analysis of uncorrected prevalence may be acceptable.     

Avian Communities of Fragmented South-Temperate Rainforests in Chile

The diversity and relative abundance of south-temperate rainforest birds decreased as the size of the habitat patch decreased. Ecological categories, including endemics, mutualists (pollinators, seed dispersers), understory species, and species dependent on large trees, were not differentially sensitive to patch size. Nevertheless, most of the species with at least marginally significant declines were endemic (6 of 7 species), covered nesters (6 of 7 species), and understory dwellers (5 of 7 species). Some mutualists and big-tree users were also affected. The losses will become more severe as clearing of the forest continues. Possible mitigation measures include leaving small stands of forest and corridors between habitat patches and, in certain circumstances, alternative agricultural practices.     

Landsat image and sample design for water reservoirs (Rapel dam Central Chile)

Spatial heterogeneity of the Rapel reservoir surface waters is analyzed through Landsat images. The image digital counts are used with the aim or developing an aprioristic quantitative sample design.Natural horizontal stratification of the Rapel Reservoir (Central Chile) is produced mainly by suspended solids. The spatial heterogeneity conditions of the reservoir for the Spring 86-Summer 87 period were determined by qualitative analysis and image processing of the MSS Landsat, bands 1 and 3. The space-time variations of the different observed strata obtained with multitemporal image analysis.A random stratified sample design (r.s.s.d) was developed, based on the digital counts statistical analysis. Strata population size as well as the average, variance and sampling size of the digital counts were obtained by the r.s.s.d method.Stratification determined by analysis of satellite images were later correlated with ground data. Though the stratification of the reservoir is constant over time, the shape and size of the strata varys.     

Variation in some chemical parameters and organic matter in soils regenerated by the addition of municipal solid waste

The organic fraction of a municipal solid waste was added in different doses to an eroded soil formed of loam and with no vegetal cover. After three years, the changes in macronutrient content and the chemical-structural composition of its organic matter were studied. The addition of the organic fraction from a municipal solid waste had a positive effect on soil regeneration, the treated soils being covered with spontaneous vegetation from 1 yr onwards. An increase in electrical conductivity and a fall in pH were noted in the treated soils as were increases in macronutrients, particularly N and available P and the different carbon fractions. Optical density measurements of the organic matter extracted with sodium pyrophosphate showed that the treated soils contained an organic matter with less condensed compounds and with a greater tendency to evolve than the control. A pyrolysis-gas chromatography study of the organic matter extracted with pyrophosphate showed large quantities of benzene both in the treated soils and control; pyrrole was also relatively abundant, although this fragment decreased as the dose rose. Xylenes and pyridine were present in greater quantities in the control and furfural in the treated soils. Three years after addition to the soil, the organic matter had a higher proportion of fragments derived from aromatic compounds and a smaller proportion derived from hydrocarbons. Similarity indices showed that, although the added and newly formed organic matter 3 yr after addition continued to differ from that of the original soil and to be more mineralizable, the transformations it has undergone made it more similar to the original organic matter of the soil than it was at the moment of being added.     

MACROPHYTE STANDING CROP AND PRIMARY PRODUCTWITY IN SOME FLORIDA SPRING-RUNS1

ABSTRACT: A survey of 31 Florida spring-runs was conducted to estimate their submerged macrophyte standing crop and primary productivity. The standing crops of submerged vegetation were not significantly (p > 0.05) correlated to either total nitrogen (r = 0) or total phosphorus (r =?0.20) concentrations, but standing crops were significantly (p < 0.01) correlated to the percentage of the spring-run's water surface shaded by marginal vegetation (r =?0.76). Maximum daily rates of primary productivity were positively correlated with average submerged macrophyte standing crops (r = 0.81; p < 0.001) and inversely correlated with the degree of shading by marginal vegetation (r =? 0.43; p < 0.05).     

拉普拉塔河流域以及巴塔哥尼亚地区及相关海域水生态栖息地的改变

本文描述了南美大陆南部陆地和东南沿海地区环境特性及水生栖息地和群落的现状(GIWA巴塔哥尼亚大陆架亚区),结果来自一项GIWA项目框架任务所完成的一份全面评估,绝大部分依据的是公开发表的数据.分析主要集中在跨边界水资源目前的情况和人类活动带来的影响.内陆水体的栖息地和群落变化主要是由为发电和其他用途而建的水坝和水库引起的.从活水环境到净水环境影响了生境,造成了生物群落的改变.在拉普拉塔(La Plata)河流域,外来入侵物种使本地物种消失.过度捕捞和污染影响了生物多样性,造成了海洋栖息地质量下降.本篇文章讨论了相关的原因,讨论了布宜诺斯艾利斯省和渔业资源由两国共享的阿根廷-乌拉圭公共渔业区对沿海生态环境的政策选择.