Two plant species, arugula (Eruca sativa) and mustard (Brassica juncea) were field-grown under four soil management practices: soil mixed with municipal sewage sludge (SS), soil mixed with horse manure (HM), soil mixed with chicken manure (CM), and no-mulch bare soil (NM) to investigate the impact of soil amendments on the concentration of glucosinolates (GSLs) in their shoots. GSLs, hydrophilic plant secondary metabolites in arugula and mustard were extracted using boiling methanol and separated by adsorption on sephadex ion exchange disposable pipette tips filled with DEAE, a weak base, with a net positive charge that exchange anions such as GSLs. Quantification of GSLs was based on inactivation of arugula and mustard myrosinase and liberation of the glucose moiety from the GSLs molecule by addition of standardized myrosinase (thioglucosidase) and spectrophotometric quantification of the liberated glucose moiety. Overall, GSLs concentrations were significantly greater (1287 µg g?1 fresh shoots) in plants grown in SS compared to 929, 890, and 981 µg g?1 fresh shoots in plants grown in CM, HM, and NM soil, respectively. Results also revealed that mustard shoots contained greater concentrations of GSLs (974 µg g?1 fresh shoots) compared to arugula (651 µg g?1 fresh shoots). 相似文献
The aim of this study was to assess the seasonal development of the physicochemical (pH, organic C, organic N, extractable P, Ca2+, Mg2+) and biological soil properties (microbial biomass, activities of urease, dehydrogenase and alkaline phosphatase) of the topsoil of mine deposition sites that differed based on the material used exclusively for their creation: (a) marlstones, (b) red-grey formations (RGF), and (c) fly ash (FA), during the first year after their creation. Our hypothesis was that all deposition sites, regardless the material they consist of, present equal opportunities for the establishment of spontaneous vegetation. All macronutrients concentrations (P, Ca2+, and Mg2+) remained constant with time and were found to be higher in the FA sites. Organic C, organic N, all enzyme activities, and microbial biomass were higher in the RGF and marl depositions, with marl sites presenting the highest values. All values of biological variables, with the exception of alkaline phosphatase, increased with time. The alkaline environment along with the slow improvement in soil biological properties of the FA sites seemed to present the most unfavorable conditions for spontaneous vegetation growth. On the contrary, the other two spoil materials presented significant improvement in the initial stages of soil formation in terms of soil functionality. 相似文献
A vibrant debate about the future direction of biodiversity conservation centers on the merits of the so‐called new conservation. Proponents of the new conservation advocate a series of positions on key conservation ideas, such as the importance of human‐dominated landscapes and conservation's engagement with capitalism. These have been fiercely contested in a debate dominated by a few high‐profile individuals, and so far there has been no empirical exploration of existing perspectives on these issues among a wider community of conservationists. We used Q methodology to examine empirically perspectives on the new conservation held by attendees at the 2015 International Congress for Conservation Biology (ICCB). Although we identified a consensus on several key issues, 3 distinct positions emerged: in favor of conservation to benefit people but opposed to links with capitalism and corporations, in favor of biocentric approaches but with less emphasis on wilderness protection than prominent opponents of new conservation, and in favor of the published new conservation perspective but with less emphasis on increasing human well‐being as a goal of conservation. Our results revealed differences between the debate on the new conservation in the literature and views held within a wider, but still limited, conservation community and demonstrated the existence of at least one viewpoint (in favor of conservation to benefit people but opposed to links with capitalism and corporations) that is almost absent from the published debate. We hope the fuller understanding we present of the variety of views that exist but have not yet been heard, will improve the quality and tone of debates on the subject. 相似文献
The consensus in the literature holds that female-headed households (FHHs) are more vulnerable to social and economic exclusion than male-headed households (MHHs). This paper investigates the socioeconomic determinants of household cooking fuel choices across MHHs and FHHs, using the rich Nigerian Demographic Health Survey data. Using the exogenous switching treatment effect regression (ESTER) technique, the study is able to unravel differences in socioeconomic effects of gender inequality on cooking fuel choices in Nigeria. The results validate the energy ladder hypothesis in the Nigerian case and show that the choices of dirty fuel (biomass) is more prevalent among the de-jure FHH when compared with the de-facto FHH and MHHs. Also, the probability of biomass-use among MHHs would have fallen by 1.3% if MHHs had similar socioeconomic attributes as the FHHs. In the same vain for FHHs, the probability of kerosene-use would have increased by 2%. The study observed no gender gap in kerosene-use. Thus, the established gender gap in biomass- and kerosene-use would have reduced to 6.7% and 2.8%, respectively, if the de-facto FHHs had same socioeconomic attributes as the de-jures. Considering the traditional gendered household division of labor within the households, de-jure FHHs’ energy choices may be due to limited economic opportunities that guarantees cleaner energy options.
The spatial and temporal variations of some trace metals in the surface sediments of Cochin Estuary were analyzed along with their geochemical associations to identify the possible sources, bioavailability and the health risks posed by them. The dominance of kaolinite and suggested that clay minerals distribution is influenced by sediment sorting. Total metal analysis revealed enrichment for Cd, Pb and Zn due to anthropogenic activities. The speciation analysis established that notwithstanding the large availability, carbonate as well as organic and sulfides bound fractions showed negligible associations with most of the metals. Hydrous Fe–Mn oxides appeared to play a major role in controlling the fate and transport of these metals in the sediments of Cochin Estuary. Lower contribution of the residual fractions for Cd (21%–26%), Pb (<60%) and Zn (24%–42%) indicated an obvious increase of other geochemical fractions. Risk assessment analysis revealed that regardless of total concentration, none of the analyzed metals were at safe levels in the estuary as appreciable percentages were found to be associated with mobile geochemical forms. The speciation study conspicuously established that the metals originating from non-geogenic sources are largely associated with the labile fractions and hence are more detrimental to the aquatic biota. 相似文献
The present study attempts to highlight the value of multi-character approaches for defining thresholds in fish ontogeny,
like the onset of the juvenile period. We developed techniques to objectively define the transition from larval to juvenile
development using morphometric as well as morphological characters and exemplify the multi-character approach on newly settled
white sea-breams (Diplodus sargus sargus) collected from the eastern Mediterranean. The morphometric analysis was based on principles of multivariate allometry whereas
the analysis of morphology, on assigning a suite of selected characters (here related to external morphology and osteological
development) into larval, transforming and juvenile states. The size-at-change in multivariate allometric growth (Lm) is considered here to denote mean length-at-metamorphosis. An almost perfect match is demonstrated between Lm (‘multivariate morphometry’) and mean size-at-morphological change (‘multivariate morphology’) in white sea-bream. 相似文献
Per-and polyfluoroalkyl substances(PFASs) are ubiquitous in sludge and water from waste water treatment plants, as a result of their incorporation in everyday products and industrial processes. In this study, we measured several classes of persistent PFASs,precursors, transformation intermediates, and newly identified PFASs in influent and effluent sewage water and sludge from three municipal waste water treatment plants in Sweden, sampled in 2015. For sludge, samples from 2012 and 2014 were analyzed as well.Levels of precursors in sludge exceeded those of perfluoroalkyl acids and sulfonic acids(PFCAs and PFSAs), in 2015 the sum of polyfluoroalkyl phosphoric acid esters(PAPs) were 15–20 ng/g dry weight, the sum of fluorotelomer sulfonic acids(FTSAs) was 0.8–1.3 ng/g,and the sum of perfluorooctane sulfonamides and ethanols ranged from non-detected to 3.2 ng/g. Persistent PFSAs and PFCAs were detected at 1.9–3.9 ng/g and 2.4–7.3 ng/g dry weight, respectively. The influence of precursor compounds was further demonstrated by an observed substantial increase for a majority of the persistent PFCAs and PFSAs in water after waste water treatment. Perfluorohexanoic acid(PFHxA), perfluorooctanoic acid(PFOA), perfluorohexane sulfonic acid(PFHxS), and perfluorooctane sulfonic acid(PFOS)had a net mass increase in all WWTPs, with mean values of 83%, 28%, 37% and 58%,respectively. The load of precursors and intermediates in influent water and sludge combined with net mass increase support the hypothesis that degradation of precursor compounds is a significant contributor to PFAS contamination in the environment. 相似文献