Improving the feasibility of aquaculture feed by using microalgae

Environmental Science and Pollution Research - The aquaculture industry is an efficient edible protein producer and grows faster than any other food sector. Therefore, it requires enormous amounts...     

Analysis of stability of silica nano-particle-laden microbubble dispersion

Microbubbles are small gas-filled bubbles which have wide application in various industries. The stability of microbubble is of primary concern for the application of microbubble. In this research, the stability of microbubble dispersion generated using CTAB surfactant is analyzed by drainage mechanism. The stability of microbubble dispersion is studied on the basis of the half-life of microbubble dispersion. Microbubble dispersion gas fraction and apparent rise velocity of interface of microbubble dispersion are also calculated. The size of microbubble is estimated from the apparent rise velocity of interface of microbubble dispersion. Further, silica nano-particles are added to the surfactants to study their effect on the stability of microbubble dispersion. The observed results clearly indicate that the stability of microbubble dispersion is significantly affected by the surfactant concentration and the weight of silica nano-particle in the liquid. Similar results were observed for the apparent rise velocity of interface and bubble size of dispersion. The present work may be beneficial for the application of microbubble in various chemical and biochemical industries and scientific community.

     

Heavy metal pollution and forest health in the Ukrainian Carpathians

The Ukrainian Carpathians are characterized by high air pollution caused by emissions from numerous industries. We have been monitoring the state of forests in this region since 1989. The highest levels of tree defoliation (>30%) are found close to industrial emission sources and in the upper mountain forests of the Ivano-Frankivsk and Chernivtsi regions. This is caused by a combination of strong anthropogenic influences (pollution, illegal uses, recreation) as well as poor site and climatic conditions. In the Ivano-Frankivsk region, Cd and Mo accumulate in forest soils; Cr, Mo and Zn soil concentrations are higher than their limit levels; and Pb concentrations exceed toxic levels close to industrial areas (10% of the region territory). Local background levels of heavy metals are greatly exceeded in snow close to industrial regions. Analysis of correlation matrices shows that the chemical elements Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn occur at pollution levels in natural ecosystems in the Ukrainian Carpathians. Maximum concentrations of toxic elements occur in the oak forest zone; the most industrially developed area of the region. Toxic heavy metals in the Ukrainian Carpathians forests enter with precipitation and dustfall, then become fixed in soil and accumulate in leaves, needles of vascular plants and mosses. Concentrations of these metals decrease with altitude: highest in the oak forests, less in beech, and lowest in the spruce forest zones. However, some chemical elements have the highest concentrations in spruce forests; V in needles, As in snow, and Ba and Al in soils.     

Biodegradation of trifluralin in Harran soil

Degradation of trifluralin (alpha, alpha, alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) was investigated in soils taken from three different locations at Harran region of Turkey under laboratory conditions. Surface (0-10 cm) soils, which were taken from a pesticide untreated field Gürgelen, Harran-1 and Ikizce regions in the Harran Plain. were incubated in biometer flasks for 350 days at 25 degrees C. Ring-UL-14C-trifluralin was applied at the rate of 2 microg g(-1) with 78.7 kBq radioactivity per 100 g soil flask. Evolved (14)CO2 was monitored in KOH traps throughout the experiment. Periodically, soil sub-samples were removed and extracted by supercritical fluid extraction (SFE). Unextractable soil-bound 14C residues were determined by combustion. During the 350 days incubation period 6.6, 5.4, and 3.3/' of the applied radiocarbon was evolved as (14)CO2 from the Harran-1, Gürgelen, and Ikizce soil, respectively. At the end of 350 days the SFE-extractable and bound 14C-trifluralin residues were 39.0 and 29.2% of the initially applied herbicide in Gürgelen soil. The corresponding values for Harran-1 and Ikizce soils were 36.2, 28.4% and 41.6, 18.5% respectively.     

Persistence of residues in water and sediment of a fresh-water lake after surface application of technical chlordane

A fresh-water lake, free from detectable pesticide residues before this study, was treated with a commercial formulation of technical chlordane. Water and sediment samples were analysed for chlordane residues 7, 24, 52, 279. and 421 days after treatment. Residues moved rapidly from the water to the lake bottom, supporting earlier results of a laboratory study with other organochlorines. In water, alpha- and gamma-chlordane concentrations remained proportional to total chlordane concentrations, as determined by total-peak area measurements of gas-liquid chromatogrammes. But in bottom sediments, alpha- and gamma-chlordane were more persistent than other constituents of technical chlordane, supporting recent evidence that quantification of technical chlordane residues on the basis of gamma-chlordane quantification only (or that of alpha- and gamma-chlordane only), can lead to incorrect results and that this method, although simple and fast, should no longer be recommended.     

Upgrading food wastes by means of bromelain and papain to enhance growth and immunity of grass carp (<Emphasis Type="Italic">Ctenopharyngodon idella</Emphasis>)

The fast growing of global aquaculture industry accompanied with increasing pressure on the supply and price of traditional feed materials (e.g., fish meal and soy bean meal). This circumstance has urged the need to search alternative sources of feed stuff. Food waste was used as feed stuff in rearing fish which possess substantial protein and lipid. Grass carp are major species reared in Hong Kong with lower nutritional requirements; it is also an ideal species for investigating the feasibility of using food waste as fish feeds for local aquaculture industry. The growth and immunity, reflected by total protein, total immunologlobulin (IgI), and nitroblue tetrazolium (NBT) activity of grass carp blood, were depressed when feeding with food waste feeds without enzymes. However, the supplementation of bromelain and papain in fish feed enhanced the efficient use of food waste by grass carp, which in turn improved the fish immunity. The present results indicated that the addition of those enzymes could enhance the feed utilization by fish and hematological parameters of grass carp, and the improvement on growth and immunity superior to the control (commercial feed) was observed with the addition of bromelain and papain supplement. Addition of 1 and 2 % mixture of bromelain and papain could significantly enhance the lipid utilization in grass carp.     

Organic pollution of the Büyük Menderes River,Turkey and effects on aquaculture

Water quality was measured at eight stations on the Buyuk Menderes River in Turkey (Ad?güzel dam, Yenice regülator, Sarayköy bridge, Feslek regülator, Yenipazar bridge, Ayd?n bridge, Koçarl? bridge, Söke regülator) between 2000 and 2013 in February, April, June, August, October and December. The resulting data were evaluated in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), ammoniac–nitrogen (NH₃–N), nitrite–nitrogen (NO₂–N), nitrate–nitrogen (NO₃–N) and orthophosphate (o-PO₄) aquaculture. According to the analysis, while river water pollution generally varied during each year, samples from certain measurement points demonstrated high pollution levels throughout the year. In this study, water parameters were classified according to the “Turkish water pollution control regulation.” The studied parameters are also compared with TS 266 and WHO guidelines. While levels at Sarayköy station were generally higher than other stations, values at Ad?güzel dam were the lowest, giving it the best water quality of the eight stations. The highest values on a yearly basis were obtained in 2007 due to the severe drought in the Menderes basin within which irrigation water levels fell to 4255 m³/ha. The BOD, COD levels are the lowest in 2009 and highest in 2007; the DO level is lowest in 2007 and highest in 2009; NH₃–N, NO₂–N, and NO₃–N parameters are the lowest in 2007 and highest in 2009; and the o-PO₄ are at the lowest level in 2004 and seen as the highest in 2007. Analysis of the data was performed by SPSS 21 statistics program. One direction ANOVA was applied to the data, which were also subject to Tukey multiple comparison tests. Differences between groups were evaluated at p?<?0.05. Box–plot graphs were used to demonstrate the data distribution. In the study, it was analyzed, the effect of fish species and pollution involved in the Büyük Menderes River so far on fish species.     

Circumpolar status of Arctic ptarmigan: Population dynamics and trends

Rock ptarmigan (Lagopus muta) and willow ptarmigan (L. lagopus) are Arctic birds with a circumpolar distribution but there is limited knowledge about their status and trends across their circumpolar distribution. Here, we compiled information from 90 ptarmigan study sites from 7 Arctic countries, where almost half of the sites are still monitored. Rock ptarmigan showed an overall negative trend on Iceland and Greenland, while Svalbard and Newfoundland had positive trends, and no significant trends in Alaska. For willow ptarmigan, there was a negative trend in mid-Sweden and eastern Russia, while northern Fennoscandia, North America and Newfoundland had no significant trends. Both species displayed some periods with population cycles (short 3–6 years and long 9–12 years), but cyclicity changed through time for both species. We propose that simple, cost-efficient systematic surveys that capture the main feature of ptarmigan population dynamics can form the basis for citizen science efforts in order to fill knowledge gaps for the many regions that lack systematic ptarmigan monitoring programs.

     

Engineered nanoparticles in wastewater and wastewater sludge – Evidence and impacts

Nanotechnology has widespread application in agricultural, environmental and industrial sectors ranging from fabrication of molecular assemblies to microbial array chips. Despite the booming application of nanotechnology, there have been serious implications which are coming into light in the recent years within different environmental compartments, namely air, water and soil and its likely impact on the human health. Health and environmental effects of common metals and materials are well-known, however, when the metals and materials take the form of nanoparticles – consequential hazards based on shape and size are yet to be explored. The nanoparticles released from different nanomaterials used in our household and industrial commodities find their way through waste disposal routes into the wastewater treatment facilities and end up in wastewater sludge. Further escape of these nanoparticles into the effluent will contaminate the aquatic and soil environment. Hence, an understanding of the presence, behavior and impact of these nanoparticles in wastewater and wastewater sludge is necessary and timely. Despite the lack of sufficient literature, the present review attempts to link various compartmentalization aspects of the nanoparticles, their physical properties and toxicity in wastewater and wastewater sludge through simile drawn from other environmental streams.