Rainbow trout (Oncorhynchus mykiss) is one of the most-widely cultivated cold fresh water fish in the world. Gamasyab River, with a length of about 200 Km, is one of the longest rivers of Iran. The aim of this research is to determine the effects of trout farm effluents on this river water.  From a total of 24 trout farms in the area,  four farms were randomly selected and three sampling statio...

The simplified acid peroxydisulphate digestion of soil water extract was evaluated for determination of total dis solved phosphorus by molybdenum-blue colorimetry in comparison with direct P-detection in water extract by the ICP-AES technique. The research was conducted on 79 agricultural soils with different agrochemical characteristics. The results of the colorimetric P detection in water ext...

This paper proposes an ensemble of support vector regression and complementary neural networks to predict the Water Quality Index (WQI) for Tha Chin River, Nakhonpathom, Thailand. The data set was collected during the year 2002-2007. Four parameters are used in the prediction which are dissolved oxygen, total solid, biological oxygen demand, and suspended solid. It is found that an ensemble of ...

In order to obtain representative dissolved and solid samples from the aquatic environment, a spectrum of sampling methods are available, each one with different advantages and drawbacks. This article evaluates the use of discrete sampling and time-integrated sampling in illustrating medium-term spatial and temporal variation. Discrete concentration index (CI) calculated as the ratio between di...

elevated atmospheric carbon dioxide and other green house gases have increased the earth temperature in recent century, which it affects all biochemistry cycles in soils. to examine the effect of atmospheric co2 concentration and temperature on n forms in soil solution in a calcareous soil, an experiment was conducted in a completely randomized design with factorial arrangement in the laborator...

Arsenic released by bottom sediments was determined by experiments in which the sediments were artificially re-suspended using a particle entrainment simulator (PES) to simulate river conditions. Sediment cores were collected from various tributaries to drinking water reservoirs in Connecticut spiked with arsenic, and run in the PES at simulated bed-flow shear stresses from 0.0 to 0.6 N/m(2). U...

Mercury (Hg) is a toxicant of global concern that accumulates in organisms as methyl Hg. The production of methyl Hg by anaerobic bacteria may be limited in anoxic sediments by the sequestration of divalent Hg [Hg(II)] into a solid phase or by the formation of elemental Hg [Hg(0)]. We tested the hypothesis that nanocrystalline mackinawite (tetragonal FeS), which is abundant in sediments where H...