A major influence on the environment of active volcanic areas is expected from continuous input of chemical species pertaining to fumarolic activities occurring during inter-eruptive intervals.
The systematic investigations carried out during thirteen years in the island of Vulcano (Italy) showed also substantial contributions to phreatic waters and soils of minor constituents and trace metals from volcanic rocks with no negligible influence on growing crops.
Greater extents of these phenomena have been observed for products of hydromagmatic volcanic activity or of long-lasting weathering processes. 相似文献
Rhizostoma pulmo is one of the most abundant scyphomedusae along the Mediterranean coasts. To understand changes in the population densities
of the medusa stage and its relationship with the benthic stage, we describe all developmental stages from the life cycle
of R. pulmo, from the scyphistoma stage to young medusae reared in the laboratory. Mature scyphistomae showed a mean total body length
of 1.7 mm and the average tentacle number was 16. Asexual reproduction occurred by lateral budding, podocyst and pedalocyst
production. Each strobila released up to 8 ephyrae that had a mean total body diameter of 3.5 mm. Moreover, we also present
data on the temporal and spatial distribution of the species in the Catalan Sea and the coastal lagoon on Mar Menor (NW Mediterranean)
during the years 2007–2009. In the Catalan Sea, the presence of adult R. pulmo was recorded as extended along the whole coast, but most of the observation was concentrated in the central area; the highest
abundances were recorded during the months of July and August. The highest number of observations was detected in 2008 in
coincidence with the inter-annual variation observed in the Mar Menor lagoon. 相似文献
Heavy metal and antibiotic resistance have been shown to have a strong correlation in nature, and their inter-relation is an important subject of study. We report an analysis of surface waters of the Mololoa River in the municipality of Tepic, state of Nayarit, Mexico. This river has two distinctive sources of contamination: sewage waters and trash confinements. Our findings demonstrate a correlation between the river flow pattern and resistance to heavy metals or to heavy metals and antibiotics in isolated bacteria of the genus Enterococcus, specifically Enterococcus faecalis. The Mololoa River provides a model to study the relationship between water flow and generation of biodiversity, and more importantly, it constitutes a model for studying genetic diversity of bacteria affecting human health. 相似文献
Mealybugs have a haplodiploid reproduction system, with paternal genome elimination (PGE); the males are diploid soon after fertilization, but during embryogenesis, the male paternal set of chromosomes becomes heterochromatic (HC) and therefore inactive. Previous studies have suggested that paternal genes can be passed on from mealybug males to their sons, but not necessarily by any son, to the next generation. We employed crosses between two mealybug species—Planococcus ficus (Signoret) and Planococcus citri (Risso)—and between two populations of P. ficus, which differ in their mode of pheromone attraction, in order to demonstrate paternal inheritance from males to F2 through F1 male hybrids. Two traits were monitored through three generations: mode of male pheromone attraction (pherotype) and sequences of the internal transcribed spacer 2 (ITS2) gene segment (genotype). Our results demonstrate that paternal inheritance in mealybugs can occur from males to their F2 offspring, through F1 males (paternal line). F2 backcrossed hybrid males expressed paternal pherotypes and ITS2 genotypes although their mother originated through a maternal population. Further results revealed other, hitherto unknown, aspects of inheritance in mealybugs, such as that hybridization between the two species caused absence of paternal traits in F2 hybrid females produced by F1 hybrid females. Furthermore, hybridization between the two species raised the question of whether unattracted males have any role in the interactions between P. ficus and P. citri. 相似文献
Environmental Geochemistry and Health - Urban soils are often mixed with extraneous materials and show a high spatial variability that determine great differences from their agricultural or natural... 相似文献
The implementation of eco-toxicological assessment in South America is presently limited due to significant scientific information gaps concerning native species and their potential use as biomarkers. Recently, a common southern hemisphere fish species, Astyanax fasciatus, has been pointed out as a potential bio-indicator to anthropogenic pollution. This is a small, abundant, Neotropical characid, which is widely distributed from Central America south, to the Rio de la Plata Basin of western Uruguay. Our study found a statistically significant increase of coproporphyrin, uroporphyrin and protoporphyrin concentrations in hepatic tissues of A. fasciatus collected from a stream segment with high anthropogenic disturbance (due mainly to agricultural derivatives and motor vehicle transportation activities). Although the area studied showed differences in up and downstream limno-chemical parameters, these differences were not related to the increase of hepatic porphyrin concentrations. Based on the results of our study, we conclude that A. fasciatus is a good bio-indicator of exposure to environmental contaminants, and we propose that this abundant fish species be considered as a sentinel organism for monitoring potential disturbances to freshwater ecosystems. 相似文献
Specific-site data of metal concentration in cattle manure from NW Spain and a multicompartment fate and exposure model were used to evaluate metal fate and the main routes of exposure after a 100 year period of application of cattle manure as fertiliser in pastureland. Risk assessment was performed as a probabilistic analysis, and using a conservative worst-case exposure scenario. An accumulation model was used to predict the metal concentration in each environmental medium of concern. The incremental risk was estimated for the population inhabiting the surroundings of the area by a general multiexposure model. Monte Carlo simulations were performed to analyse uncertainty of the results. Furthermore, a sensitivity analysis was carried out to identify the contribution to variance by the different metals and exposure routes. Among the five pathways evaluated, the ingestion of meat and milk from cattle grazing in the area represents the main contribution to total exposure. The results indicate that the incremental risk to human health for people living in the surroundings of pasturelands due to continuous application of cattle manure after a 100 year period are not negligible for the metals considered (Cd, Cu, Ni, Pb and Zn), posing a total Reasonable Maximum Exposure (RME) of 0.75, being the ingestion of meat the main exposure pathway. 相似文献
The wastes from the macro-fungus Agaricus bisporus were used as an eco-friendly and low-cost adsorbent for the treatment of colored effluents containing the recalcitrant dyes, acid red 97 (AR97) and crystal violet (CV). The macro-fungal waste presented an amorphous structure, composed of particles with different sizes and shapes. Also, it presents typical functional chemical groups of proteins and carbohydrates with a point of zero charge of 4.6. The optimum conditions for the dosage were found to be as follows: 0.5 g L−1 with an initial pH at 2.0 for the AR97 and 8.0 for the CV. From the kinetic test, it was found that it took 210 min and an adsorption capacity of 165 mg g−1 for the AR97. Concerning the CV kinetics, it took 120 min to reach the equilibrium and it achieved an adsorption capacity of 165.9 mg g−1. The Elovich model was the most proper model for describing the experimental data, achieving an R2 ≥ 0.997 and MSE ≤ 36.98 (mg g−1)2. The isotherm curves were best represented by the Langmuir model, predicting maximum adsorption capacity of 372.69 and 228.74 mg g−1 for the AR97 and CV, respectively. The process was spontaneous and favorable for both dyes. The ∆H0 values were 9.53 and 10.69 kJ mol−1 for AR97 and CV, respectively, indicating physical and endothermic adsorption. Overall, the wastes from Agaricus bisporus have the potential to adsorb cationic and anionic dyes, thus solving environmental problems related to water quality and residue disposal.