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Phosphate ions is one of the chemical pollutants that enters to the surface and underground water through municipal, industrial and agricultural wastewater. The aim of this study is to investigate the removal of phosphate from wastewater by Chlorella vulgaris and Spirulina platensis. To this purpose the microalgae added to 350 ml wastewater in lab experiment. In order to evaluate the effect of phosphorus removal, the experiment were performed during 8 days. The initial dry weight of Chlorella vulgaris and Spirulina platensis in wastewater samples were 0.02 and 0.05 g/L, respectively. During the growth period, the concentration of phosphate in aqueous solution were measured on days 1st, 4th, 6th and 8th by APHA standard methods through Bio spec-1601 spectrophotometer. Based on the results, the percentage of phosphorus removal by Chlorella vulgaris was 40.65, 38.0124.45 and 72.21 , and by Spirulina platensis was 20.13, 20.01, 10.44 and 42.79 for days 1 to 4, 4 to 6, 6 to 8 and 1 to 8, respectively. The final dry weight of Chlorella vulgaris and Spirulina platensis in wastewater samples were 3.93 and 1.93 g/L, respectively. From this study it can be concluded that the algae are able to remove phosphorus from wastewater and Chlorella vulgaris has higher ability of reducing phosphorus from waste water, and could be good candidate to reduce the phosphate in wastewater treatment.

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Aims: Haft Barm is a series of five small lakes in the southern Zagros region which has encountered recent rapid development of human settlement. This article reports a survey on its essential ecological attributes.
Methods: Water samples were taken from three locations in March and June 2020 and analyzed regarding physical and chemical factors and plankton communities. Trophic state and primary production were estimated.
Findings: Results showed water temperature 8.2–23.1 °C, dissolved oxygen 6.3–8.3 mg.L^-1, salinity as electrical conductivity 739 – 971 µS.cm^-1, total nitrogen 0.1–1.1 mg.L^-1, and total phosphorus 0.4 and 3.8 mg.L^-1. Algae of the lake consisted of 24 taxa, the highest density of which counted 23360 cells per liter in June, and the Chlorophyceae were the dominant group. The Zooplankton composition was of four taxa from Cladocera (Bosmina sp. and Daphnia sp.), Copepoda (Cyclops sp.), and Rotifera (Rotaria sp.), with the highest densities in Rotaria (35 individuals per liter). Phragmites sp., and Juncus sp. were the dominant species in the macrophyte community besides Polygonum amphbium, and Potamogeton pectiatus. The very high concentration of total phosphorus is a strong sign for predicting a eutrophic condition. The average trophic index is estimated at 88, which suggests a eutrophic to hyper-eutrophic state for the lake. The estimated primary production of the lake was 1114 gC.m^-2.A^-1.
 

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This research aims to determine the mercury (Hg) in the muscle and liver tissues of Otolithes ruber species and its human health risk assessment due to its consumption.
Material & Methods: In this study thirty fish samples were taken from the Imam Khomeini port in northwest of the Persian Gulf, in July. Then, the total mercury was measured by the Mercury Advanced Analyzer (254 AMA manufactured by Leco).
Findings: The mean concentrations of Hg in the muscle of O. ruber species were 0.112± 0.015 µg.g^-1 d.w that were below the limits for fish proposed by WHO, FAO, USEPA, FDA and MAFF and the mean concentrations of Hg in the liver tissues were 0.714± 0.113. µg.g^-1 d.w. Value of muscle/liver ratio was about 0.16 that revealed high contamination of the region with the mercury element. EDI and EWI lower than PTDI and PTWI and THQ<1.00 showed that the consumption of the mentioned fish will not pose an acute risk to the health of the consumers. Based on CRlim and CRmm in the studied fish for different human groups, a potential human health risk was identified for children.
Conclusion: In general, the main conclusion of this work showed that there is no serious warning or prohibition against consuming this fish by adults, however it should be mentioned that the risk assessment caused by the presence of other heavy elements as well as organic pollutants in O. ruber fish can have an impact in determining the permissible limit of consumption of this species.

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Over the past few years, due to the shortage of forest resources as well as the increasing consumption of paper and paperboard, many pulp and paper manufacturers have developed the use of different sources of recycled (secondary) fibers. Therefore, recycling of paper is an effective and eco-friendly way to preserve forest resources, which eventually save the natural diversity and energy. The use of biotechnology in various sectors of the cellulosic products industries such as bio-pulping, bio-bleaching, bio-deinking, bio-wastewater treatment, etc. has been considered and good achievements have been obtained in this field. One of the most important applications of biotechnology in the cellulosic industries is the use of enzymes in the processing of recycled fibers. The use of enzymatic technologies, as environmental friendly process, has led to changes in industrial processes as much as possible and indicated great potential in solving many problems of recycled fibers, especially problems related to waste paper deinking, pulp drainage rate, fiber hornification, refining and stickies materials. In general, deinking with enzymes under acidic or neutral conditions declines the chemicals usage and reduces the yellowing of recycled paper under conventional alkaline deinking conditions. Today, the use of cellulosic enzymes (cellulase and hemicellulase) and oxidative enzymes (such as laccase) as well as amylase and pectinase have shown acceptable results for deinking different types of waste paper and most experiments in semi-industrial as well as industrial units have shown that deinking with them can reduce the cost of chemicals, increase the separation of ink particles