Inter-seasonal maintenance of individual nest site preferences in hawksbill sea turtles

Within a single population of hawksbill sea turtles (Eretmochelys imbricata), we found a behavioral polymorphism for maternal nest site choice with respect to beach microhabitat characteristics. Some females preferred to nest in littoral forest and in places with overstory vegetation cover, and others preferred to nest in more open, deforested areas. Nest site choice was consistent within and between nesting seasons two years apart. This was not a result of females simply returning to the same location along the shoreline; beach sections used by individual turtles varied between seasons. Nest site choice was not influenced by changes in beach environment (e.g., beach width and foliage cover) or by changes in females' reproductive output (e.g., clutch size), suggesting that fidelity to particular microhabitats is a major determinant of the observed nesting patterns. Because hawksbills exhibit temperature-dependent sex determination, if the behavioral polymorphism in nest site choice has a genetic basis, as is plausible, then this would have implications for sex ratio evolution and offspring survival. By taking an individual-based approach to the study of maternal behavior we reveal previously overlooked individual variation and hope to provide some impetus for more detailed studies of nest site choice.     

Mechanochemical activation for lead extraction from spent cathode ray tube

Journal of Material Cycles and Waste Management - In this study, a mechanochemical activation technique to effectually extract lead from the funnel glass of cathode ray tube (CRT) is proposed. A...     

Status of electronic waste recycling techniques: a review

Environmental Science and Pollution Research - The increasing use of electrical and electronic equipment leads to a huge generation of electronic waste (e-waste). It is the fastest growing waste...     

Determination of acaricide residues in saudi arabian honey and beeswax using solid phase extraction and gas chromatography

Determination of acaricide residues of flumethrin, tau-fluvalinate, coumaphos, and amitraz in honey and beeswax was carried out using a rapid extraction method utilizing C-18 SPE cartridges and an analytical method utilizing GC with ECD, NPD, and MSD detectors for the four acaricides. Recovery percentages from the extraction method ranged from 90-102%, while the minimum detection levels ranged from 0.01-0.05 mg/kg for the acaricides. Nine of the 21 analyzed samples were found to be contaminated with the acaricides tau-fluvalinate and coumaphos. Neither flumethrin nor amitraz was detected in any of the honey or wax samples. Coumaphos was found only in honey samples in which two samples exceeded the tolerance levels set by EPA and EC regulations. It has not been detected in beeswax. Five honey samples and eight beeswax samples were found to be contaminated with tau-fluvalinate. One of the wax samples was contaminated with a relatively high residue of tau-fluvalinate and contained above 10 mg/kg.     

Ginkgo biloba mitigates silver nanoparticles-induced hepatotoxicity in Wistar rats via improvement of mitochondrial biogenesis and antioxidant status

Environmental Science and Pollution Research - Silver nanoparticles (AgNPs) are noble metal nanoparticles, due to their good physicochemical properties, which have been exploited in biological...     

The effect of biochar on severity of soil water repellency of crude oil-contaminated soil

Environmental Science and Pollution Research - Crude oil contamination adversely affects soil water repellency. In this study the effect of biochar on this soil characteristic has been investigated...     

Uranium isotopes in groundwater from the “Jeffara coastal aquifer” (southeastern Tunisia)

The distributions of ²³⁸U and ²³⁴U in groundwater from the “Jeffara aquifer” were studied by using alpha spectrometric methods. The concentration ranges of ²³⁸U and ²³⁴U/²³⁸U activity ratios were 1.34 ± 0.17 to 3.43 ± 0.38 ppb, and 1.43 ± 0.23 to 1.82 ± 0.27 respectively. Variations in concentrations can be related not only to lithostratigraphic formations but also to different origins of groundwater. U content of Jeffara are found very similar to those of Continental Intercalaire aquifer in both El Hamma and Chenchou regions, indicating that the Continental Intercalaire is the dominant source of the groundwater.     

Uptake of arsenic by alkaline soils near alkaline coal fly ash disposal facilities

The attenuation of arsenic in groundwater near alkaline coal fly ash disposal facilities was evaluated by determining the uptake of arsenic from ash leachates by surrounding alkaline soils. Ten different alkaline soils near a retired coal fly ash impoundment were used in this study with pH ranging from 7.6 to 9.0, while representative coal fly ash samples from two different locations in the coal fly ash impoundment were used to produce two alkaline ash leachates with pH 7.4 and 8.2. The arsenic found in the ash leachates was present as arsenate [As(V)]. Adsorption isotherm experiments were carried out to determine the adsorption parameters required for predicting the uptake of arsenic from the ash leachates. For all soils and leachates, the adsorption of arsenic followed the Langmuir and Freundlich equations, indicative of the favorable adsorption of arsenic from leachates onto all soils. The uptake of arsenic was evaluated as a function of ash leachate characteristics and the soil components. The uptake of arsenic from alkaline ash leachates, which occurred mainly as calcium hydrogen arsenate, increased with increasing clay fraction of soil and with increasing soil organic matter of the alkaline soils. Appreciable uptake of arsenic from alkaline ash leachates with different pH and arsenic concentration was observed for the alkaline soils, thus attenuating the contamination of groundwater downstream of the retired coal fly ash impoundment.     

Effects of increasing temperatures on biomarker responses and accumulation of hazardous substances in rope mussels (Mytilus galloprovincialis) from Bizerte lagoon

This study examined the influence of increasing temperatures in spring and summer on biochemical biomarkers in Mytilus galloprovincialis mussels sampled from Bizerte lagoon (northern Tunisia). Spatial and seasonal variations in a battery of seven biomarkers were analyzed in relation to environmental parameters (temperature, salinity, and pH), physiological status (condition and gonad indexes), stress on stress (SoS), and chemical contaminant levels (heavy metals, polycyclic aromatic hydrocarbons (PAHs), and PCBs) in digestive glands. Integrated biological response (IBR) was calculated using seven biomarkers (acetylcholinesterase (AChE), benzo[a]pyrene hydroxylase (BPH), multixenobiotic resistance (MXR), glutathione S-transferase (GST), catalase (CAT), malondialdehyde (MDA), and metallothioneins (MT). Seasonal variations in biological response were determined during a critical period between spring and summer at two sites, where chemical contamination varies by a factor of 2 for heavy metals and a factor 2.5 for PAHs. The analysis of a battery of biomarkers was combined with the measurement of physiological parameters at both sites, in order to quantify a maximum range of metabolic regulation with a temperature increase of 11 °C between May and August. According to our results, the MT, MDA, CAT, and AChE biomarkers showed the highest amplitude during the 11 °C rise, while the BPH, GST, and MXR biomarkers showed the lowest amplitude. Metabolic amplitude measured with the IBR at Menzel Abdelrahmen—the most severely contaminated station—revealed the highest metabolic stress in Bizerte lagoon in August, when temperatures were highest 29.1 °C. This high metabolic rate was quantified for each biomarker in the North African lagoon area and confirmed in August, when the highest IBR index values were obtained at the least contaminated site 2 (IBR = 9.6) and the most contaminated site 1 (IBR = 19.6). The combined effects of chemical contamination and increased salinity and temperatures in summer appear to induce a highest metabolic adaptation response and can therefore be used to determine thresholds of effectiveness and facilitate the interpretation of monitoring biomarkers. This approach, applied during substantial temperature increases at two sites with differing chemical contamination, is a first step toward determining an environmental assessment criteria (EAC) threshold in a North African lagoon.