Evaluation of pesticides residues distribution in fresh and smoked body parts of Clarias gariepinus and assessment of possible health risks in Nigeria

Pesticides residues in fresh and smoked body parts of Clarias gariepinus were investigated to evaluate their contamination status and risks to human health. The results gave an overview of the contamination levels of these (head, body trunk and liver) fish parts. The pesticides [organochlorine (OC), organophosphorus (OP), pyrethroids (PY) and others like: guazatine, methoprene, metalaxyl and imidachloprid] concentration in the fresh and smoked body parts ranged from 0.002 to 0.221 µg/kg and 0.002 to 0.175 µg/kg, with mean concentration of 0.002–0.218 µg/kg and 0.002–0.126 µg/kg, respectively. Smoking was observed to reduce the overall pesticide concentration as follows: head (0.23 µg/kg or 17.3%), liver (0.34 µg/kg or 29.8%) and muscles (0.41 µg/kg or 27.2%). The pesticides contents were significantly lower than standard daily intake and the risk associated with consumption of the fish also showed that the fish posed no potential threat to consumers.     

Irradiation of sorbents by ions of polymorphic metals for modeling <Superscript>90</Superscript>strontium sedimentation

Background, Aims and Scope Advances in radioecology can support improvements in environmental remediation technologies, especially by illuminating interaction processes between polymorphic metal radionuclides and various materials and their ions in aqueous solutions. This study modeled interaction processes of ⁹⁰Sr with transitive metals to delineate the behavior of polymorphic metal radionuclides. Experimental and modeling results confirmed Sr sedimentation was sensitive to the physical impact of radionuclides on various sorbents and possible chemical reactions occurring between the radionuclides and sorbents. Methods Models were developed to simulate ⁹⁰Sr sedimentation process, and the potential physical and chemical reactions accompanying the process. Models were verified, inorganic salts were used as sorbents to absorb metal cations, activity levels were recorded before and after mixing the inorganic salts while the efficiency of sedimentation using the heavy metals composites was quantified. Results and Discussion This research demonstrates that the process of the sedimentation is complex and occurs in several stages. Micro-structural analysis shows that zones of interaction between the sorbent and source metal are formed during the irradiation of the target’s metal surface. Electrical-microscopic analysis indicates that the composition of the formed zones of interaction of Ti (Sr) with target metals has various structures. Roentgenophase analysis indicates that the interaction of the ions of a precipitable source and a target occurs according to constitution diagrams of equilibrium systems. The results indicate that application of inorganic salts composites based on modeling increases the efficiency of the deactivation of aqueous solutions when compared to standard aluminum sulfate composite. Conclusions Experimental and modeling results confirm ⁹⁰Sr sedimentation is sensitive to the physical impact of radionuclides on various sorbents and possible chemical reactions occurring between the radionuclides and sorbents. The models support estimation of the physical impact of polymorphic metal radionuclides on various components of sorbents and possible chemical reactions occurring between the radionuclides and sorbents during the interaction. Inorganic salt composites deactivate and clear ⁹⁰Sr and Sr⁺² from water. This paper is openly accessible!     

Cyanobacteria as a Food Source for Invertebrates: Results of a Model Experiment

Russian Journal of Ecology - Cyanobacterial blooms are regarded as a global environmental problem. The role of cyanobacteria in the food web of water bodies is still unclear. We have carried out an...     

交通源对西安夏季空气质量影响模拟研究

本文应用WRF-CHEM模式模拟分析了2016年6月西安市大气污染过程。模式准确地模拟了西安地区大气臭氧(O_3)、细颗粒物(PM_(2.5))以及二氧化氮(NO_2)的时空变化趋势,较好地再现了天气形势以及大气污染的演变过程。根据近年来西安市交通排放量的增加制定敏感性试验,结果表明:西安市20%交通排放量在研究时段内平均PM_(2.5)质量浓度贡献量为4.5μg?m~(-3),模拟时段内O_3平均贡献量为4.8μg?m~(-3),西安市20%交通排放量在研究时段内的平均NO_2贡献量为2.7μg?m~(-3),而且污染物浓度越高,交通源排放量的影响越显著。