Environmental Science and Pollution Research - The aim of this review was to evaluate if micronucleus assay in oral exfoliated cells is a suitable tool for biomonitoring children exposed to... 相似文献
The aim of this study was to determine the origin (human, bovine or porcine) and the concentration of the fecal sources of contamination in waters from Santa Lucía basin and Uruguay River in Uruguay by using host-specific viral markers (adenoviruses and polyomaviruses) as microbial source tracking (MST). Between June 2015 and May 2016, monthly collections of surface water samples were performed in six sites in Santa Lucía basin and four sites in Uruguay River (n = 120 samples). Viral concentration was carried out using an absorption-elution method. Detection and quantification of human and porcine adenovirus (HAdV and PAdV, respectively) and human and bovine polyomavirus (HPyV and BoPyV, respectively) were performed by quantitative PCR (qPCR). To evaluate the infectivity of circulating HAdV, an integrated cell culture-qPCR (ICC-qPCR) was used. A logistic regression analysis was carried out to estimate the influence of environmental variables on the virus presence in surface waters. Overall, HAdV was the prevalent (18%; 21/120) followed by BoPyV (11%; 13/120) and HPyV (3%; 3/120), whereas PAdV was not detected in this study. The mean concentration ranged from 1.5 × 104 genomic copies/L (gc/L) for HAdV to 1.8 × 102 gc/L for HPyV. Infective HAdVs were observed in two out of ten analyzed samples. A significant effect of environmental temperature (p = 0.001) and river (p = 0.012) on the presence of human viruses was found. These results suggest that fecal contamination could affect the water quality of these rivers, showing deficiencies in the procedure of sewage discharge from regional cities, livestock and dairy farms.
Fossilized soft tissues, occasionally found together with skeletal remains, provide insights to the physiology and functional morphology of extinct organisms. Herein, we present unusual fossilized structures from the cortical region of bone identified in isolated skeletal remains of Middle Triassic nothosaurs from Upper Silesia, Poland. The ribbed or annuli-shaped structures have been found in a sample of partially demineralized coracoid and are interpreted as either giant red blood cells or as blood vessel walls. The most probable function is reinforcing the blood vessels from changes of nitrogen pressure in air-breathing diving reptiles. These structures seem to have been built of extensible muscle layers which prevent the vessel damage during rapid ascent. Such suspected function presented here is parsimonious with results of previous studies, which indicate rarity of the pathological modification of bones associated with decompression syndrome in Middle Triassic nothosaurs. 相似文献
Leadership is considered an essential element in guaranteeing the safe running of organizations. The purpose of the present study is to find out how leader behaviours influence employees’ safety behaviours (perceived safety behaviours) in the nuclear field. In an attempt to answer this question, the authors of this research have considered the way this influence is exercised, taking into consideration some important factors like safety culture and safety climate. To achieve this, the empowerment leadership model, based on a behavioural approach to leadership, was used. The sample was made up of 566 employees from a Spanish nuclear power plant. The results indicated that when safety culture was strong, leader behaviour generated a higher safety climate among the members, which predicted their perceived safety behaviours. Support was found for a structural model linking leadership and safety behaviour to safety culture and safety climate. The implications of these findings for the theory of safety and the way they can be put into practice are outlined. 相似文献
Improving access to clean water has the potential to make a major contribution toward poverty reduction in rural communities
of Lao P.D.R. This study focuses on stream water quality along a Mekong basin tributary, the Houay Xon that flows within a
mountainous, mosaic land-use catchment of northern Lao P.D.R. To compare direct water quality measurements to the perception
of water quality within the riparian population, our survey included interviews of villagers. Water quality was found to vary
greatly depending on the location along the stream. Overall, it reflected the balance between the stream self-cleaning potential
and human pressure on the riparian zone: (i) high bacteria and suspended load levels occurred where livestock are left to
free-range within the riparian zone; (ii) very low oxygen content and high bacteriological contamination prevailed downstream
from villages; (iii) high concentrations of bacteria were consistently observed along urbanized banks; (iv) low oxygen content
were associated with the discharge of organic-rich wastewater from a small industrial plant; (v) very high suspended load
and bacteria levels occurred during flood events due to soil erosion from steep cultivated hill slopes. Besides these human
induced pollutions we also noted spontaneous enrichments in metals in wetland areas fed by dysoxic groundwater. These biophysical
measurements were in agreement with the opinions expressed by the majority of the interviewees who reported poor and decreasing
water quality in the Houay Xon catchment. Based on our survey, we propose recommendations to improve or maintain stream water
quality in the uplands of northern Lao P.D.R. 相似文献
The acorn barnacle, Semibalanus balanoides, is thought to release larvae in response to phytoplankton blooms, but there is evidence that another, unidentified cue for
release may exist. We conducted high-frequency sampling in Little Harbor, Massachusetts, USA, to determine whether early-stage
larval abundance was related to several environmental variables, and to characterize vertical distributions of the larvae.
Larval concentrations peaked at 2.52 and 1.02 individuals l−1 during two storms. Larvae were more abundant near the surface than near the bottom. We suggest the hypothesis that turbid
conditions and upward-swimming behavior may protect newly-released larvae from predation and cannibalism. Future studies should
test this hypothesis with barnacles and other invertebrates. 相似文献
We adopt viability theory to assess the sustainability of the world’s forests while taking into account some of the competing
economic, social, and environmental uses of these forests, namely, timber production, poverty alleviation through agriculture,
and air quality as well as the negative externalities that these uses create. We provide insights on the different trade-offs
faced to achieve sustainability and draw some policy implications as to what is the path leading to sustainability in the
long run. 相似文献
A mathematical model which represents the transport processes of heavy metals and fine sediments in a fluvial stream was developed.
The model consists of a three-equation system: the first one for total chromium concentration in the water column, CTw, the second one for total suspended sediment concentration, Sw, and the third one for chromium concentration in bed sediments, r. The third equation represents the chromium exchange between the water column and bed sediments by two processes: diffusion
of soluble chromium and erosion/deposition of chromium sorbed to sediments. The basic assumption of the model is the instantaneous
equilibrium. The main parameters are the partition coefficients in the water column and bed sediments, the depth of the active
bed sediment layer, and the mass transfer coefficient between the water column and sediment pore water. The numerical model
approximates the equations of advection–dispersion for chromium in water and suspended sediments by using a Eulerian third-order
scheme. Numerical vs. analytical solutions were considered satisfactory for different initial, boundary, and sedimentological
conditions. In order to estimate the impact of a chromium side discharge, the model was implemented for the Salado River in
a reach of 65.6-km long (Santa Fe, Argentina). The results showed the effect of chromium discharge on almost the whole reach,
then the vulnerability of the water quality in the Salado River when the flow was low was evidenced. When comparing the computed
and measured results, the former showed a reasonable representation of the presence of chromium in water and bed sediments. 相似文献
We report a combined two-year seasonal monitoring of Suquía River basin using both chemical parameters and biomarkers measured in Jenynsia multidentata, aiming to correlate external levels of contaminants with the response of oxidative stress biomarkers in this fish. Identified pollution sources correspond to city sewage as well as agricultural and small industry activities downstream from Córdoba city. Physicochemical parameters integrated into a water quality index (WQI) were measured in Suquía River during dry and wet seasons. Ag, Mn, Cu, Cr, Ni, Fe, Pb and Zn were also monitored in water and sediment samples. Biomarkers include detoxication and antioxidant enzymes: catalase (CAT), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glutathione reductase (GR). Enzymes showed a pollution dependent response, with increased activities in fish collected close to the sewage exit and progressive drop further downstream, matching changes in the Water Quality index. The combined use of biomarkers with water quality parameters allowed both the identification of pollution sources and the evaluation of effects of contaminants on the aquatic biota. 相似文献