during estuarine mixing of fresh water with saline water and due to the flocculation process, aportion of dissolved metals come into particulate phase, and the dissolved load decreases. this process plays an important role in self-purification of heavy metals in rivers. in this study, flocculation of cu, mn, ni, pb and zn during mixing of cheshme-kileh river water with caspian sea water has bee...

conclusions according to the average of wqi index, quality of water was good in station number one, medium in station number two, and bad in the rest of stations. according to the wilcox index, qualities of water in third station were medium and in the rest were good. results by using wqi, the best water quality was reported in station number one with the scalar quantity of 71.11 (water with be...

Twenty-three stream sites representing a range of forested, agricultural, and urban land uses were sampled in the South Platte River Basin of Colorado from July through September 2002 to characterize water quality during drought conditions. With a few exceptions, dissolved ammonia, Kjeldahl nitrogen, total phosphorus, and dissolved orthophosphate concentrations were similar to seasonal historic...

large amounts of degradable wastes including sewage water and agricultural waste or nutrients that stimulate growth of organic matter are discharged into the caspian sea. as a result, average dissolved oxygen concentration in deeper layers is decreasing. this paper presents distribution and seasonal variations of the concentration of dissolved oxygen over the southern shelf of the caspian sea a...

The flocculation of dissolved heavy metals is a process which has an important effect on decreasing the concentration of the colloidal elements during estuarine mixing of river water and sea or ocean water. During this important process, a large amount of colloidal elements change into particles in the form of flock and the dissolved loads decline. This study is performed to evaluate the mechani...

Understanding interactions between permanently frozen soils and stream chemistry is important in predicting the effects of management, natural disturbance and changing permafrost distribution on stream ecosystems and nutrient budgets in subarctic watersheds. Chemical measurements of groundwater, soil water and stream water were made in two watersheds in the taiga of interior Alaska. One watersh...

Fertilization exceeding crop requirements causes an accumulation of phosphorus (P) in soils, which might increase concentrations of dissolved and colloidal P in drainage. We sampled soils classified as Typic Haplorthods from four fertilization experiments to test (i) whether increasing degrees of phosphorus saturation (DPS) increase concentrations of dissolved and colloidal P, and (ii) if criti...

Computer models are a rapid, inexpensive way to identify agricultural areas with a high potential for P loss, but most models poorly simulate dissolved P release from surface-applied manures to runoff. We developed a simple approach to predict dissolved P release from manures based on observed trends in laboratory extraction of P in dairy, poultry, and swine manures with water over different wa...