Effects of two organophosphorus insecticides on some biochemical constituents in the nervous system and liver of rabbits

Male Baladi rabbits were acutely and sub-chronically intoxicated with cyanofenphos and profenophos. The levels of cholesterol, triglycerides, B-lipoproteins and total proteins were determined in the serum, brain, spinal cord and sciatic nerve of rabbits. Moreover, the activities of alkaline phosphatase, acid phosphatase and glutamic-pyruvic transaminase were determined in the liver of the animals. The whole studies revealed that the biochemical constituents were highly affected by the tested insecticides. Also, the liver function suffered from adverse effects of the tested insecticides.     

Modelling and assessment of South African elephant Loxodonta africana population persistence

The use of a quantitative population growth model to investigate the persistence of South African elephant populations is explored. The model provides quantitative assessments of population persistence and confidence intervals for estimated parameters based purely on population size estimates. The analysis supports the view that most of the larger populations in the region are secure. This view is further supported by a lack of density dependent effects in most of the recovering populations and the high population rates of increase observed. This predominantly positive prognosis is in contrast with that emerging from most of the rest of the African continent where the populations are under greater threat because of habitat restriction and direct human conflict. This preliminary assessment of elephant population persistence suggests that “viable” populations may lie between 400 and 6000 individuals. Although not inconsistent with information-greedy genetic and demographic models, the relationship between population growth versus genetic and demographic models should be further investigated. The implementation of a metapopulation management strategy towards these smaller populations is advocated. In addition, as all of the populations included in this analysis have been afforded some degree of protection since the 1920s, continued protection would be a prerequisite for their continued survival.     

The Outcome of Northern Fur Seal Harvesting: The Results of Calibration of Mathematical Models Based on Observation Data (the Example of Tyulenii Island Population)

Tendencies in the dynamics of harvested northern fur seal (Callorhinus ursinus) population on the Tyulenii Island have been analyzed in detail. The results show that retardation of reproduction (decrease in the numbers of pups) and decline in the survival of young females (up to 3 years of age) by the late 1980s resulted in a reduction of the total number of females and a significant increase in the proportion of older females. This tendency changed during the later observation period (after 1988–1989) due to increase in the survival of young females: the female population has gradually recovered, with the proportion of young females increasing at the expense of old females (aged over 10 years). The age composition of males has also changed: the proportion of young animals has decreased, while that of large mature males (bulls) has increased. Moreover, the number of bulls continues to increase and has already exceeded the level that formerly provided for the well-being of the population. This, a paradoxical situation has arisen: the numbers of females and bulls are increasing, whereas pup production remains at a low level.

     

The Effect of Vaccinium vitis-idaea on Properties of Mountain-Meadow Soil under Alpine Lichen Heath

Russian Journal of Ecology - Abstract—The study of the effect of mycorrhiza symbiosis on the transformation of carbon and nitrogen compounds in soils is important in view of the necessity to...     

Environmental pollution in Africa

Mining and minerals industries are fast-growing, but at the same time, they have gained more attention due to their impacts over the environment and society. This research aims to provide new insights into the topic of perception and awareness toward sustainability in industrial mining in Brazil. The work included in-depth interviews with a set of companies’ managers/directors focusing in particular on aspects related to the social and environmental dimensions, including communication and relationship with the community, impact assessment and mitigation strategies. The knowledge and use of for formal indicators was also evaluated and analyzed through the proposed Model for Sustainability Assessment of Mining (SAoM model), which was applied to all participating companies. The results put in evidence the existing gap between large and small companies, with these last ones showing lower awareness for the impacts of their activities. The lack of community engagement and of local stakeholders’ involvement, as well as the disregard for actions to mitigate their environmental and social impacts, is the main challenges to be overcome by this sector. The sector has then a long path to go toward sustainability and an active involvement of public institutions is required to allow for its development without compromising locals welfare.     

Carbon Emission from the Surface of Coarse Woody Debris in Korean Pine Forests of Southern Primorye

Carbon dioxide fluxes from the surface of coarse woody debris (CWD) have been measured in Korean pine forests of the southern Sikhote-Alin mountain range. The seasonal dynamics of oxidative conversion of CWD carbon have been evaluated, and average values of the CO₂ emission rate have been determined for CWD fragments of three tree species at different stages of decomposition. The degree of decomposition is an important factor of spatial variation in CO₂ emission rate, and temporal variation in this parameter is adequately described by an exponential function of both CWD temperature and air temperature (R² = 0.65–0.75).     

A Comparative Study on the Archives of Xanthine Oxidase and Aldehyde Oxidase in Different Fish Species from Two Rivers in the Western Niger-Delta

Glycaemia, a classical indicator of stress, xanthine oxidase and aldehyde oxidase which are involved in phase I detoxication were investigated in two different fish species from two rivers with different pollution levels in the Western Niger-Delta. Four sampling zones covering the entire lengths of Warri and Ethiope Rivers respectively were used in this study. For each species of fish five were obtained from a sampling zone in a river. Blood glucose was significantly higher (P < 0.001) in M. electricus from Warri River (82.13 +/- 5.50 mg cm(-3)) compared to the same species from Ethiope River (36.47 +/- 1.49 mg cm(-3)). With the same parameter a similar profile was observed for C. gariepinus; Warri River (56.92 +/- 10.31 mg cm(-3)); Ethiope River (37.65 +/- 0.90 mg cm(-3)) which was also significant (P < 0.01). The activity of xanthine oxidase in M. electricus from Warri River (255.80 +/- 41 it mol cm(-3)) was significantly higher (P < 0.001) compared to the value obtained for the same species (108 +/- 22.36 micro mol cm(-3)) from Ethiope River. Also the activity of xanthine oxidase in C. gariepinus from Warri River (197 +/- 34.65 micro mol cm(-3)) was significantly higher (P < 0.001) when matched with the value obtained for the same species (78.40 +/- 26.84 micro mol cm(-3)) from Ethiope River. That blood glucose level was related to xanthine oxidase activity in the two fish species from Warri River was supported by the high positive correlation between these two parameters (M. electricus. r = 1: C. gariepinus, r = 0.71). The activity of aldehyde oxidase in C. gariepinus from Warri River (143.80 +/- 28.45 micro mol cm(-3)) was significantly higher (P < 0.001) compared to the value obtained for the same species (61.20 +/- 15.21 micro mol cm(-3)) from Ethiope River. A similar profile in aldehyde oxidase activity observed for M. electricus; Warri River (130 +/- 28.39 micro mol cm(-3)); Ethiope River (89 +/- 19.70 micro mol cm(-3)) but an inferior statistical variation (P < 0.05) was obtained. The results obtained in this study indicate that the level of xanthine oxidase in M. electricus is a more specific marker and to a lesser extent its activity in C. gariepinus in monitoring environmental stress due to pollution.     

CO and NO2 pollution in a long two-way traffic road tunnel: investigation of NO2/NOx ratio and modelling of NO2 concentration

The CO, NO and NO2 concentrations, visibility and air flow velocity were measured using continuous analysers in a long Norwegian road tunnel (7.5 km) with traffic in both directions in April 1994 and 1995. The traffic density was monitored at the same time. The NO2 concentration exceeded Norwegian air quality limits for road tunnels 17% of the time in 1994. The traffic through the tunnel decreased from 1994 to 1995, and the mean NO2 concentration was reduced from 0.73 to 0.22 ppm. The ventilation fan control, based on the CO concentration only, was unsatisfactory and the air flow was sometimes low for hours. Models for NO2 concentration based on CO concentration and absolute air flow velocity were developed and tested. The NO2/NOx ratio showed an increase for NOx levels above 2 ppm; a likely explanation for this phenomenon is NO oxidation by O2. Exposure to high NO2 concentrations may represent a health risk for people with respiratory and cardiac diseases. In long road tunnels with two-way traffic, this study indicates that ventilation fan control based on CO concentration should be adjusted for changes in vehicle CO emission and should be supplemented by air flow monitoring to limit the NO2 concentration.     

Effects of exposure of aquatic snails to sublethal concentrations of waste drilling fluid

Static bioassays were carried out using two aquatic snails (Pilia sp. and Lanistes sp.) as test organisms in soft natural dilution water, with waste drilling fluid as the test material, at 28±2°C. Comparison of results for the control and different concentrations of the waste drilling fluid were made by means of the F-statistic method. The waste drilling fluid was practically non-toxic to the two aquatic snails.     

Species Distribution Models of Freshwater Stream Fishes in Maryland and Their Implications for Management

Species distribution models (SDMs) are often used in conservation planning, but their utility can be improved by assessing the relationships between environmental and species response variables. We constructed SDMs for 30 stream fishes of Maryland, USA, using watershed attributes as environmental variables and presence/absence as species responses. SDMs showed substantial agreement between observed and predicted values for 17 species. Most important variables were natural attributes (e.g., ecoregion, watershed area, latitude/longitude); land cover (e.g., %impervious, %row crop) was important for three species. Focused analyses on four representative species (central stoneroller, creek chub, largemouth bass, and white sucker) showed the probability of presence of each species increased non-linearly with watershed area. For these species, SDMs built to predict absent, low, and high densities were similar to presence/absence predictions but provided probable locations of high densities (e.g., probability of high-density creek chub decreased rapidly with watershed area). We applied SDMs to predict suitability of watersheds within the study area for each species. Maps of suitability and the environmental and species response relationships can help develop better management plans.