Assessment of some heavy metals in surface sediments of the Aqaba Gulf, Egypt

Aqaba Gulf is an economically important marine environment in Egypt. Its coastal area was subjected to anthropogenic impact of urbanization and economic development during the last decades. The study was oriented to investigate the distribution as well as assess the heavy metal pollution status (Fe, Mn, Zn, Ni, Co, Cr, Cu, and Cd) in its surface sediment. Large heavy metals fluctuations were detected along the studied area. The results pointed out to the highly significant correlations among Fe, Cu, Ni, and Co heavy metals and their similar lithogenic origin beside their input sources. The sediment quality was performed by using the geo-accumulation index (I (geo)) and different sediment criteria guidelines; China State Bureau of Quality and Technical Supervision (CSBTS), and Canadian guidelines. Among the studied heavy metals, Cd was the only metal that showed moderate pollution for I (geo) as well as it exceeded the primary and the secondary criteria of CSBTS and the threshold effect level of the Canadian guidelines (TEL). On the other hand, the other heavy metals were within the natural background levels.     

A phospho-compost biological-based approach increases phosphate rock agronomic efficiency in faba bean as compared to chemical and physical treatments

Under arid and semi-arid conditions, direct application of phosphate rock (PR) as a source of phosphorus (P) for crop production is likely influenced by agricultural practices and soil properties. Different approaches could be used to improve the agronomic efficiency of low-grade PR over a wider range of soils and crops. In this study, biological, physical, and chemical treatments of low-grade Moroccan PR were investigated and compared through agronomic trials on faba bean grown under alkaline soil conditions. The physical treatment was based on blending PR with triple superphosphate (TSP) at 75:25 and 50:50 ratios, the biological treatments involved co-application of PR with compost at 50:50 ratio and phospho-compost elaborated from PR (20%), sewage sludge (46%), and wheat residues (34%), while the chemical treatment was obtained by a 30% acidulation of PR by phosphoric acid. Control treatments consisting of zero P application (control), PR alone, and TSP alone were considered to assess the effectiveness of the abovementioned techniques to improve PR agronomic efficiency. A pot experiment was conducted in sandy soil (Jorf Lasfar, central Morocco) for 60 days in a completely randomized design considering eight treatments. All treatments, except the control, were amended with 52 mg kg^?1 of P from different PR-based fertilizers before sowing. At the flowering stage (60-day-old plants), results indicated that all PR treatments significantly improved plant growth, root nodulation, and nutrient uptake compared to the control. The relative agronomic efficiency of pretreated PR was significantly higher with phospho-compost treatment (86%) than the partially acidulated PR (78%) or the PR/TSP blend 50:50 (64%). Likewise, P uptake, P use efficiency, number of root nodules, and N uptake all were improved under PR treatments. Our finding revealed that the biological technique based on phospho-compost yielded better compared to chemical and physical treatments.

     

Metal accumulation by three Tilapia spp. from some Egyptian inland waters

Five trace metals (Cu, Zn, Fe, Mn and Cd) were determined in different tissues and organs (muscle, liver, brain, gills, gonads and intestines) of some Tilapia spp. (Oreochromis spp. and Sarotherodon galilaues) collected from two Egyptian Lakes (Edku and Mariut, exposed to different types of pollutants), El-Umum Drain, and from the fishing farm El-Nozha Hydrodrome. Our results indicate that metal accumulation in different organs vary considerably between the same and among different Tilapia spp. There is a preferential accumulation of metals by different organs. Liver is a target organ for Cu accumulation, whereas the brain and flesh tissues clearly accumulate more levels of Zn than the other studied elements. Amongst the studied elements, Cd concentrations in the different organs are the lowest. It was found that edible parts of Tilapia spp. collected from Lake Mariut accumulate the highest levels of the studied elements (Fe, Zn, Mn and Cu for S. galilaues and Cd for Oreochromis niloticus), compared with those in the other studied areas. In general, the levels of Cd (0.0–0.11?ppm), Cu (0.25–1.85?ppm) and Zn (3.58–8.46?ppm) in the edible parts of studied fish cannot be considered as hazardous levels.     

Behavioral and metabolic effects of sublethal doses of two insecticides,chlorpyrifos and methomyl,in the Egyptian cotton leafworm, <Emphasis Type="Italic">Spodoptera littoralis</Emphasis> (Boisduval) (Lepidoptera: Noctuidae)

Insecticides have long been used as the main method in limiting agricultural pests, but their widespread use has resulted in environmental pollution, development of resistances, and biodiversity reduction. The effects of insecticides at low residual doses on both the targeted crop pest species and beneficial insects have become a major concern. In particular, these low doses can induce unexpected positive (hormetic) effects on pest insects, such as surges in population growth exceeding what would have been observed without pesticide application. Methomyl and chlorpyrifos are two insecticides commonly used to control the population levels of the cotton leafworm Spodoptera littoralis, a major pest moth. The aim of the present study was to examine the effects of sublethal doses of these two pesticides, known to present a residual activity and persistence in the environment, on the moth physiology. Using a metabolomic approach, we showed that sublethal doses of methomyl and chlorpyrifos have a systemic effect on the treated insects. We also demonstrated a behavioral disruption of S. littoralis larvae exposed to sublethal doses of methomyl, whereas no effects were observed for the same doses of chlorpyrifos. Interestingly, we highlighted that sublethal doses of both pesticides did not induce a change in acetylcholinesterase activity in head of exposed larvae.     

Antiviral Effects of Lactococcus lactis on Feline Calicivirus,A Human Norovirus Surrogate

Foodborne viruses, particularly human norovirus (NV) and hepatitis virus type A, are a cause of concern for public health making it necessary to explore novel and effective techniques for prevention of foodborne viral contamination, especially in minimally processed and ready-to-eat foods. This study aimed to determine the antiviral activity of a probiotic lactic acid bacterium (LAB) against feline calicivirus (FCV), a surrogate of human NV. Bacterial growth medium filtrate (BGMF) of Lactococcus lactis subsp. lactis LM0230 and its bacterial cell suspension (BCS) were evaluated separately for their antiviral activity against FCV grown in Crandell–Reese feline kidney (CRFK) cells. No significant antiviral effect was seen when CRFK cells were pre-treated with either BGMF (raw or pH 7-adjusted BGMF) or BCS. However, pre-treatment of FCV with BGMF and BCS resulted in a reduction in virus titers of 1.3 log₁₀ tissue culture infectious dose (TCID)₅₀ and 1.8 log₁₀ TCID₅₀, respectively. The highest reductions in FCV infectivity were obtained when CRFK cells were co-treated with FCV and pH 7-adjusted BGMF or with FCV and BCS (7.5 log₁₀ TCID₅₀ and 6.0 log₁₀ TCID₅₀, respectively). These preliminary results are encouraging and indicate the need for continued studies on the role of probiotics and LAB on inactivation of viruses in various types of foods.     

Water quality index modeling using random forest and improved SMO algorithm for support vector machine in Saf-Saf river basin

Environmental Science and Pollution Research - The water quality index is one of the prominent general indicators to assess and classify surface water quality, which plays a critical role in river...     

Reducing ammonia emission by aluminum sulfate addition in litter and its influence on productive,reproductive, and physiological parameters of dual-purpose breeding hens

Environmental Science and Pollution Research - This research investigated the impact of aluminum sulfate (AS) as amendment to different types of litter (new, reused, and mixed litters) for reducing...     

Radiological impacts of phosphogypsum

This study was carried out to assess the radiological impact of Syrian phosphogypsum (PG) piles in the compartments of the surrounding ecosystem. Estimating the distribution of naturally occurring radionuclides (i.e. (226)Ra, (238)U, (232)Th, (210)Po and (210)Pb) in the raw materials, product and by-product of the Syrian phosphate fertilizer industry was essential. The data revealed that the concentrations of the radionuclides were enhanced in the treated phosphate ore. In PG, (226)Ra content had a mean activity of 318 Bq kg(-1). The uranium content in PG was low, ca. 33 Bq kg(-1), because uranium remained in the phosphoric acid produced. Over 80% of (232)Th, (210)Po and (210)Pb present partitioned in PG. The presence of PG piles did not increase significantly the concentration of (222)Rn or gamma rays exposure dose in the area studied. The annual effective dose was only 0.082 mSv y(-1). The geometric mean of total suspended air particulates (TSP) ca. 85 μg m(-3). The activity concentration of the radionuclides in filtrates and runoff waters were below the detection limits (ca. 0.15 mBq L(-1) for (238)U, 0.1 mBq L(-1) for (232)Th and 0.18 mBq L(-1) for both of (210)Po and (210)Pb); the concentration of the radionuclides in ground water samples and Qattina Lake were less than the permissible limits set for drinking water by the World Health Organisation, WHO, (10, 1 and 0.1 Bq L(-1) for (238)U, (232)Th and both of (210)Po and (210)Pb, respectively). Eastern sites soil samples of PG piles recorded the highest activity concentrations, i.e. 26, 33, 28, 61 and 40 Bq kg(-1) for (226)Ra, (238)U, (232)Th, (210)Po and (210)Pb, respectively, due to the prevailing western and north-western wind in the area, but remained within the natural levels reported in Syrian soil (13-32 Bq kg(-1) for (226)Ra, 24.9-62.2 Bq kg(-1) for (238)U and 10-32 Bq kg(-1) for (232)Th). The impact of PG piles on plants varied upon the plant species. Higher concentrations of the radionuclides were recorded for grass in comparison to broad-leaved plants. Among the species that grow naturally on PG piles, Inula, Ecballium and Polygonium may be radionuclides accumulators. A determined effort is needed at a national level to achieve a common and coherent approach to regulate PG piles or to consider it a resource material rather than waste or residue.     

Imposex and butyltin concentrations in Bolinus brandaris (Gastropoda: Muricidae) from the northern Tunisian coast

The imposex incidence and butyltin concentration i.e. tributyltin with its di- and mono-substituted metabolites were investigated in the muricid Bolinus brandaris sampled from two sites on the northern Tunisian coast (the Lagoon of Bizerta and the small Gulf of Tunis). Both populations had imposex, with stages of imposex development varying between VDS 1 and VDS 4.3. All imposex indices (imposex frequency (I %), female penis length, female vas deferens length, vas deferens sequence index, relative penis length index, and vas deferens length index) were significantly higher in snails from the Bizerta lagoon. Butyltins were detected in the whole tissues of both sexes from the two sites. TBT levels were higher in gastropods collected from the lagoon of Bizerta (12.65 ±1.48 ng Sn g^???1 dw in female and 15.21 ±1.13 ng Sn g^???1 dw in male) than in individuals from the Gulf of Tunis (10.71 ±1.26 ng Sn g^???1 dw in female and 11.65 ±1.63 ng Sn g^???1 dw in male), corroborating the data of imposex analysis. These results confirmed that B. brandaris could be used as a bioindicator species of butyltin pollution in the studied areas. In addition, this study provided baseline data that could serve for long-term monitoring of TBT pollution in Tunisia, since legislation to reduce the use of TBT-based antifouling paints has not been introduced yet.     

Transboundary Pollution and Absorptive Capacity

The impact of the investment in absorptive capacity on transboundary pollution is studied by considering two countries, each of them regulating a firm. Firms can invest in inventive research and in absorptive research to lower their pollution intensity. The absorptive research enables a firm to capture part of the inventive research made by the other one. We show that by means of adequate emission taxes, original and absorptive research and development (R&D) subsidies, regulators can reach the non-cooperative social optimum. Interestingly, we show that the investment in absorptive research enables non-cooperating regulators to better internalize transboundary pollution. The higher is the learning parameter of absorption, the greater is the proportion of transboundary pollution internalized. Therefore, it is recommended for the international community to make the patent laws more flexible and enabling learning from the research made by others more interesting. Moreover, the investment in absorptive R&D may lead to multiple equilibria necessitating non-cooperating countries to coordinate on an equilibrium, which constitutes an incentive for them to cooperate.