Water is one of the most utilized natural resources by humans, animals, and plants for survival. On this regard, pollution of water threatens the survival of humans, animals, and plants. Aquatic life is even more threatened when the waters are polluted. The consequences can be disastrous depending on the degree of the pollutants concentrations, the kind of chemical pollutants, and the points of pollution. Many water bodies neighboring towns and cities or at the ports are highly polluted. Normally, it results from dumping garbage and hazardous chemicals or unlawful dumping by industries, markets, schools and health institutions.
The effects of water pollution are as discussed below.
1. Adverse Impact on Aquatic Flora and Fauna
Within the water bodies, there are several life forms including plants, fish, turtles, mammals, among many others that depend on water dissolved oxygen and varieties of nutrients. These are the basic needs for the survival and continuity of aquatic life and are dependent on natural processes within and outside the water bodies.
When foreign materials like chemicals, paper, plastic, and wastes from industries and consumer products are discharged or dumped into the waters, it alters most of these natural processes. For instance, oil spills cut the supply of dissolved oxygen and prevents light from penetrating into the water which is needed for cell metabolism and photosynthesis respectively.
These wastes also take considerable time to decompose thereby leaving the water contaminated for relatively long durations, ranging from months to hundreds of years. As an outcome, these pollutants harm and even kill aquatic flora and fauna. Thousands of aquatic animals like fish, birds, crabs, seagulls, and dolphins have often winded up dead on the shores owing to water pollution.
2. Eutrophication and Algal Blooms
Eutrophication is the excessive concentration of chemical nutrients in an environment to an extent that it encourages the dense growth of plant life and algae. Based on the degree of eutrophication, the effects are depletion of oxygen and extensive deterioration of water quality. As a result, it affects the survival of fish and other aquatic animals. Eutrophication is linked to increased incidence of paralytic shellfish poisoning in humans, leading to death.
Incidences of algal blooms have been witnessed more and more in the recent years on the account of water pollution. The presence of toxic algal blooms in water bodies has endangered fishing and availability of safe drinking water. It is attributed to the continued use of fertilizers and discharge if wastewater into rivers, oceans, and lakes. Toxic algal blooms have also shut down numerous water supply systems across the globe. In 2007, for instance, more than 2 million residents of Wuxi, China could not access piped drinking water for more than a week due to severe attack by algal blooms on Lake Taihu.
3. Increase in Waterborne Diseases
Water pollutants contain a variety of toxic chemical substances and pathogens. Whenever they are present in the water, they are consumed by aquatic animals which are then consumed by humans. When consumed, they can give rise to life-threatening illnesses. For example, people can acquire diseases such as hepatitis and cancer by consuming fish or seafood that has been poisoned by chemical compounds like lead and mercury.
Furthermore, mercury level in the oceans is a primary concern associated with the disruption of the normal development of the central nervous system in young children and fetuses. Due to the accumulative effects of dumping and runoff, some chemical toxins introduced into the water can cause kidney failure and reproductive disorders. People in some regions of the world have also suffered the consequences of waterborne diseases such as cholera by drinking contaminated and untreated water from streams, lakes or rivers.
4. Ecological Dead Zones and Extinction
Living things in the environment are dependent upon the continued interaction within their habitats. Per se, the interaction dependence determines ecological balance. The balance can severely be altered or damaged by water pollution thereby affecting humans and aquatic life forms in many ways.
Entry of the pollutants into waterways or large water bodies creates acidic lakes, raises the temperature of water bodies, promote the spread of algae blooms, and lead to dissolved oxygen depletion. This can force fish and other aquatic animals out of their locations in search of more adaptable water areas. In other cases, the conditions can wipe out an entire population of fish and other aquatic animal species leading to extinction.
Consequently, it creates an ecological dead zone. Some lakes and water bodies in China, North America, and Europe have been rendered dead zones owing to high levels of toxic algae blooms and increased water temperatures that made the waters unfavorable for the survival of fish as well as other aquatic animals. A study in 2008 by the Virginia Institute of Marine Science postulated that there were more than 400 dead zones globally, stretching up to 245,000 square kilometers.
5. Disruption of Food-Chains
Many animal species and humans depend on the natural food chain for survival. In this view, the presence of pollutants in the water disrupts the interconnected relationships within the food chain. This happens when small animals consume the contaminant elements of the pollutant, for instance, mercury or lead. Afterward, the small animals are consumed by fish, and the food chain continues to the higher consumer levels.
Consequently, when one of the species in the food chain dies because of water pollution, it affects the rest of the species both up and down the natural food chain. Mostly, the prey of the dead species will probably rise, but the population predating on the dead species will decrease.