Showing papers in "Journal of Environmental Science and Technology in 2018"

Comprehensive study on biodiesel produced from waste animal fats-A review

Abstract: Biodiesel is a long chain fatty acid alkyl ester molecule with robust characteristics suitable for both environment and as alternate energy resources. This paper aimed in summarizing the detailed literature study on biodiesel produced from waste animal fats discarded from leather tanneries and animal slaughter houses. This study concentrated on the extraction techniques, refining process, biodiesel production process along with its advantages and effect on engine. The fats had been proven to a viable feedstock when compared to vegetable oil and waste cooking oil in terms of productivity and economy. Various technical challenges involved in biodiesel production are food vs. fuel conflict over feedstock, auxiliary energy requirement for fat extraction and biodiesel production, Free Fatty Acid content, optimizing the reaction. Effects of biodiesel on engine application had also been discussed and will be providing wider scope of research for overcoming these short comes. This literature study affirmed that biodiesel produced from waste animal fat has a very good impact in reducing environmental pollution and moving a step ahead towards an effective sustainable development.

Air Injection Effect on Energy Consumption and Production of Hydroxyl Radicals at Plasma Anode

Abstract: Background and Objective: Plasma anode has been known as a very productive method of producing hydroxyl radicals that oxidize effectively in almost all organic and non-organic liquids. This research was conducted to investigate the effect of air injection and anode depth variation on required energy for plasma generation and production of hydroxyl radicals. Material and Method: A batch reactor (diameter 130 mm, height 190 mm) with tungsten electrodes (cathode diameter 6 mm and anode diameter 0.5 mm) was used by applying a continuous cooling system. The experimental parameters were composed of different rate of air injection (0, 2, 4, and 6 Lmin-1) and various depth of anode (5, 25, 45, and 65 mm). Current was observed at various voltage (20 – 700 V) in 30 second for each voltage. Result: The energy consumption of plasma formation was getting smaller at higher rate of air injection, while at deeper anode position, the energy consumption found higher. Although the •OH production became lower at a higher rate of air injection, the process efficiency observed higher. Conclusion: This research clarified that air injection on plasma anode and the anode depth position affected the energy consumption and production of hydroxyl radicals where the addition of air injection and variation of the anode depth could reduce energy consumption and also improved process efficiency.

Radionuclides Distribution in Marine Sediment from Abu Soma Bay, Egyptian Red Sea Coast

Abstract: Background and Objective: Measurements of natural radionuclides concentrations (226Ra, 232Th and 40K) in sediments collected from sea, rivers or ocean is significant to protect the sea water ecosystem and to human health from radiation. Materials and Methods: Thirty sediment samples were collected from Abu Soma Bay, Red Sea coast, Egypt for investigation by gamma-ray spectrometer using NaI (Tl) detector. Results: The average activity concentrations of 226Ra, 232Th and 40K were 37.2, 25.7 and 265.5 Bq kgG1. These results were compared with reported ranges in the literature from other location in the world. The radiation hazard parameters, radium equivalent activity annual dose, external hazard were also calculated and compared with the recommended levels by International Commission on Radiological Protection and united nations scientific committee on the effects of atomic radiation UNSCEAR reports. Conclusion: According to the obtained results, all samples would not present significant radiological hazards. Because there are no existing databases for the natural radioactivity in the sediment samples along Abu Soma Bay, our results are a start to establish a database for Abu Soma bay environment.

Effect of Mercury Contamination on the Diversity of Soil Arthropods in Poboya Gold Mining

Abstract: Background and Objective: Gold mining activities which use mercury have negative impacts on the diversity of soil arthropods. The present study aimed to analyze the diversity of soil arthropods in Poboya gold mining. Methodology: This study was an explorative descriptive analytical study. The research location was divided into 6 sampling points from the center of the gold mining area. One kilogram of soil was collected from every sampling point to analyze mercury, C-organic and nitrogen fiber contents of vegetation types. The sampling of soil arthropods used pitfall trap and core sampler. The analysis of difference of diversity, evenness, dominance and richness of arthropod species in every location used one-way ANOVA with level of significance p<0.05. Results: There were two classes of soil arthropods found, i.e., insecta and arachnida classes. Class insecta was the most dominant with 21,835 individuals from the total of 23,111 individuals. There was a negative correlation between the diversity of soil arthropods and mercury content of the soil. The higher the mercury contents in the soil, the lower the diversity of soil arthropods. Canonical correspondence analysis (CCA) showed that mercury content and vegetation types affected the diversity of arthropods in the mining areas (Km0, Km1, Km2) and nitrogen and C organic contents affected the diversity of arthropods in Km3, Km4 and Km5. Conclusion: Mercury contamination in the soil reduced the diversity of insect and arachnida classes arthropods in the gold mining area.

Effect of pollution and seasonal changes on litter fall and accumulation in mangrove forest (Rhizophora species) of the Niger Delta, Nigeria.

Abstract: Background and Objective: Hydrocarbon pollution and seasonal changes cause defoliation and litter fall, respectively. It is hypothesized that increasing pollution and rapid seasonal changes can cause increased litter fall. The objectives of the study were (1) To determine the annual litter fall of leaves, fruits and flowers, (2) To determine the total litter accumulation and (3) To determine the amount of litter fall in wet and dry season in highly and lowly polluted treatments. Materials and Methods: Litter fall data were collected monthly for three years at four 20×20 m plots in highly and lowly polluted plots and locations in the mangrove forests. A total of 1,440 litter samples were collected from litter traps randomly placed under mangrove trees. The litters were sorted into leaves, fruits and flowers. Results: There is a negative correlation between precipitation and litter fall (leaf r = 0.68, fruit r = 0.47, flower r = 0.31). Mean-monthly litter fall for leaves, fruits and flowers were 23.9±1.3, 9.3±0.8 and 2.8±0.6 g mG2/year, respectively. Total average litter fall was 66.5% leaf, 25.5% fruit and 8% flower. Total litter fall between locations and amongst plots did not vary significantly (p>0.05). But the 3 years cumulative litter fall was higher in highly polluted treatment (~4777 g mG2/year) than in lowly polluted treatment (4077 g mG2/year). Precipitation and season significantly influenced litter fall (p<0.0001). Dry season (November-January) had higher litter fall than wet season (February-October). Conclusion: This implies that pollution and season influence the rate of litter fall.

تغییرات آسیب شناسی بافت آبشش ماهی کپور معمولی(Cyprinus carpio) در مواجهه باغلظت های تحت کشنده نانوذرات اکسید مس

Abstract: زمینه و هدف: در عصر حاضر به دلیل کاربرد گسترده نانو ذرات مس، ورود آن‌ها به محیط‌زیست افزایش‌ یافته است. در این راستا ورود این نانو مواد به محیط‌زیست قابلیت تأثیر بر موجودات زنده ازجمله ماهی‌ها را خواهد داشت. از اینرو هدف از این مطالعه، بررسی آسیب‌شناسی بافتی ناشی از نانو ذرات مس بر بافت آبشش ماهی کپور معمولی می­باشد. روش بررسی: به‌منظور بررسی اثرات هیستوپاتولوژی نانو اکسید مس بر آبشش بچه ماهیان کپور، تعداد60 قطعه کپور معمولی جوان با میانگین وزنی2±42 گرم تهیه و در 3 گروه با سه تکرار در مواجهه با نانو اکسید مس و یک گروه شاهد در سه تکرار ماهی در نظر گرفته شد. ماهیان به مدت6 هفته با غلظت‌های40،10 و80 میلی‌گرم بر لیتر نانو اکسید مس مواجهه داده شدند. یافته­ها: عوارض مشاهده ‌شده در بافت آبشش شامل تورم سلول‌های سنگ­فرشی، آئوریسم، ادم، اتصال تیغه‌های ثانویه مجاور،کوتاه شدن تیغه‌های ثانویه و هایپرپلازی بودند. بررسی‌های آسیب‌شناسی بافت آبشش نشان داد که در غلظت‌های بالا (80 میلی‌گرم بر لیتر)، آسیب‌ها بیشتر به شکل جداشدگی، هایپرپلازی و به هم چسبیدگی لاملاها بود، در مقابل آسیب‌ها در غلظت‌های پایین (10و40میلی‌گرم بر لیتر) به شکل آئوریسم، تورم سلول‌های سنگ­فرشی و کوتاه شدن تیغه‌های ثانویه بروز نمود. بحث و نتیجه­گیری: با توجه به تغییرات ایجاد شده در بافت آبشش ماهی کپور معمولی در غلظت‌های مختلف نانو ذرات مس در مقایسه با گروه کنترل می‌توان نتیجه گرفت که نانو ذرات مس می‌تواند اثرات قابل‌توجهی بر بافت آبشش ماهیان داشته باشد. از اینرو مطالعات آسیب‌شناسی می‌تواند به ‌عنوان ابزار ساده و مناسبی جهت ارزیابی تأثیر این آلاینده‌های نوظهور انسانی بر ماهی استفاده شود.