Urbanisation
Urbanisation causing water pollutionAs more and more people move into cities and towns, a number of factors cause pollution:
the physical disturbance of land due to construction of houses, industries, roads, etc.;
chemical pollution from industries, mines, etc.;
inadequate sewage collection and treatment;
increase in fertilisers to grow more food. This results in an increase in nutrients (nitrates and phosphates) in the water which causes enhanced plant growth (algal blooms). When this plant material dies and decays the bacteria uses the oxygen in the water. This lowering of oxygen levels results in the death of other water life that needs oxygen to survive, eg. fish, etc. This process is called eutrophication;
litter, which causes disease and has a negative visual impact.
Deforestation
Clearing land for agriculture and urban growth often leads to water pollution. When soil is stripped of its protective vegetation it becomes prone to soil erosion. This leads to an increase in the murkiness of the water which can cause the following:
it can block the gills of fish;
bottom dwelling plants cannot photosynthesize as the sun’s rays cannot reach them; and
there is an increase in disease as bacteria and viruses use the soil particles as a method of transportation.