Polycyclic aromatic hydrocarbons are very toxic and persistent environmental contaminants. This study was undertaken to assess the concentrations and possible sources of 16 PAHs (Polycyclic aromatic hydrocarbons) classified by the United State Environmental Protection Agency as priority pollutants in water and sediments of the Mvudi and Nzhelele Rivers. Effluents from Thohoyandou wastewater tre...

Sea-bass (Dicentrarchus labrax) grow under different salinity regimes, from the open sea to lagoons and even rivers, but some mortality has been recorded in juvenile stages when exposed to low salinity water. Changes in water permeability of different osmoregulatory tissues could be the cause of reduction in blood osmotic pressure and death in some fish in fresh water (FW). In order to explore ...

The water index (WI) is designed to highlight inland water bodies in remotely sensed imagery. The application of WI for water body mapping is mainly based on the thresholding method. However, there are three primary difficulties with this method: (1) inefficient identification of mixed water pixels; (2) confusion of water bodies with background noise; and (3) variation in the threshold values a...

We analyzed the impact of increased water temperature on the late-season phenology of the mayfly (Baetis liebenauae). The River Gwda, unlike two other examined rivers (controls), has reservoirs along its length and thus, higher water temperature. Elevated water temperature prolonged summer diapause of the mayfly and shifted its life cycle to the later autumn: the last generation of mayflies sta...

In recent years, preservation and purgation of rivers is considered by national and international organizations that have responsible of quality control and preservation of water resources. Because of providing public health, it is most important and vital in regions that cities that rivers feed drink waters and large industrial factories located near these rivers (Li et al., 1998; Pourabadei &...

Freshwater biodiversity is under threat worldwide, but the intensity of threat in the Oriental biogeographic region of tropical Asia is exceptional. Asia is the most densely populated region on Earth. Many rivers in that region are grossly polluted, and significant portions of their drainage basins and floodplains have been deforested or otherwise degraded. Flow regulation has been practiced fo...

The objectives of this study were to investigate the seasonal and spatial variations of heavy metal pollution in the overlying water and surface sediments of the Tiaozi River, a tributary of the Liao River, which is one of the seven major rivers and one of the most heavily-polluted rivers in China. Water and sediment samples were collected over four seasons, analyzed for heavy metals (Pb, Cu, N...

Artisanal and Small-scale Gold Mining (ASGM) within the Amazon region has created several environmental impacts, such as mercury contamination and changes in water quality due to increased siltation. This paper describes the effects of water siltation on the underwater light environment of rivers under different levels of gold mining activities in the Tapajós River Basin. Furthermore, it invest...

Physicochemical characteristics and heavy metal levels in water samples from five river systems in central part of Delta State, Nigeria were investigated to access the quality status of the rivers. All the watersheds selected for study were well distributed and possessed similar geology, climate, soil, and vegetation characteristics. Studies on the water samples collected from the rivers showed...

following the collapse of the soviet :union: and independence of former soviet :union:republics, previous economic relations among centralasianrepublics changed and were replaced with the market economy. tensions have emerged between upstream and downstream countries located along transboundary rivers with downstream countries even resorting to threat of military action against possible restric...