Pros And Cons Of Water Pollution

2.5.2 Chemical control

This involves the application of chemicals to the weed so as to eradicate it. This method just like any other has its pros and cons. For instance, the use of chemicals can have potential adverse impacts on man and the environment. Furthermore, the chemicals may as well affect the fish population in the water body. The use of chemical control also poses a challenge especially when it is to be applied on a shared resource e.g. Lake Victoria. This then warrants a joint agreement from all countries that directly or indirectly depend on the resource.

2, 4-D and Glyphosate are examples of herbicides that can be used as they can kill the weeds fast. It should however be noted that the huge mass of dead plant material can lead

The effect in the change of water levels on hyacinth cover has been observed on Shagashe River and the result indicated a marked decline in the water hyacinth infestation on the river. The hyacinth was largely being washed onto the banks of the river where it subsequently dried off .This cyclical pattern had been observed over the past years and it only occured during the wet season when the rains start falling heavily. Of importance is to note that, while the removal is tremendous, there still remain some patches

It should also be noted that in some sections of the river the water hyacinth is not effectively removed by flooding or increased water levels.

A similar strategy was adopted for Shagashe River. Soon after the onset of the rainy season when a significant water hyacinth cover had been removed, there was a need to make a follow up to remove the remaining small vegetation of the weed. It was observed that most such remnant infestation is along the banks of the river. This could be removed manually. They proposed concentrating on the 4km stretch of the river in the upper course close to the source of pollution which made it feasible for routine manual and mechanical removals that could be done at a frequency of once in every month during the rainy season. They assumed that the downstream infested areas will gradually benefit from the spillover effects of the treatments done on this upstream section. The routine removal will get less frequent as we move into the dry season. The environmental management principles such as the polluter pays principle may be modified to ensure that the polluters do not only pay but actively participate in the water hyacinth