The water sample taken upstream (where there is less human activity) will contain less pollutants compared to the water sample taken downstream.
River pollution occurs when pollutants are not removed from effluent water and are discharged into the river River water is a very important source of freshwater required to sustain life. We need a constant supply of fresh water for drinking, cooking and washing. Animals living near the river, as well as fishes and aquatic plants, also depend on clean river water.
When heavy rainfall occurs, pollutants accumulated within the boundaries of the catchment area may be washed into river channels. These pollutants include a variety of agrochemicals like fertilizers and insecticides.
Waste water containing cleaning detergents, grease and other pollutants like industrial waste may be discharged into the river channel through our drainage systems, Industrial waste may contain sulfur , thereby augmenting the acidity of the river water. Sometimes, rubbish (eg. plastic bags and bottles) are also washed into the river channel.
Basic safety requirements