Water pollution has reached frightening levels in recent years despite the considerable efforts to treat and clean up wastewater. In fact, Humans add 1.2 trillion gallons of untreated wastewater into water supply each year. In addition, 14 billion pounds of plastics are dumped into the ocean each year. If we continue polluting our planet with the same rhythm, 47% of people on earth will struggle to find drinking water by 2050. Water pollution effects on Human health and environment present serious threats on the future of Humanity in our planet. In this article, we will detail the principal effects of water pollution on the environment and we will present some examples of environmental disasters caused by water pollution incidents.
There are a variety of water pollution effects on the environment. However, these effects can be summarized in the following elements:
- The algal bloom caused by water contamination with nutrients
- The effects of Chemicals and heavy metals on the aquatic life
- The threat of aquatic ecosystems by marine debris such as plastic
- The effect of ocean acidification on many marine organisms
Table of Contents
The algal bloom
The contamination of water in lakes or marine environments by nutrients used for example in the agricultural fertilization induces an excessive growth of plant and algae. This growth reduces oxygen levels in the water. This lack of oxygen, known as eutrophication, suffocates plants and animals and can create “dead zones,” where waters are essentially devoid of life. In certain cases, this excessive algal growth can also produce neurotoxins that affect aquatic wildlife.
Recently, many algal blooms occurred in some regions in the United States:
- The toxic algae bloom in California‘s Klamath River in 2017
- The algae bloom on Lake Erie near Toledo, Ohio, in 2011: At its peak, the bloom covered 1,930 square miles (5,000 square kilometers) of the nearly 10,000-square-mile (25,600-square-kilometer) lake.
Water pollution by chemicals and heavy metals
The contamination of water ecosystems by chemicals and heavy metals has very harmful effects on the aquatic life. In fact, these contaminants are known to be implicated in the reduction of an organism’s life span and its ability to reproduce. In addition, these toxic elements make their way up the food chain as predator eats prey. That’s why it was reported that tuna and other big fish accumulate high quantity of toxins, such as mercury. There are many examples of water contamination by different types of chemicals and scientific publications are studying new cases every day. However in this article, we will mention only one example with represented a huge threat to our oceans. Seven years ago, the Japanese government was forced to dump roughly 2 million gallons of radioactive water into the Pacific Ocean after the 2011 Tsunami hit.
Water pollution by oil is also one of the major forms of pollution that is threatening our water resources. In fact, 1.3 million gallons of oil is spilled into the ocean every year. In addition, for every one million tons of oil that are shipped, one ton is spilled into the waterways.
The world has been racked by major oil spill disasters many times. Here are three of the largest and worst oil spills in world history:
- The Deepwater Horizon oil spill: Also known as Gulf of Mexico Oil spill and BP oil spill and it’s considered to be the largest oil spill in the petroleum industry’s history. The oil spill continued for over three months. An estimated 53,000 barrels were flowing into the Gulf of Mexico every day. Extensive damage of the marine environment was caused by this disaster. According to the Center for Biological Diversity, the oil spill killed over 82,000 birds, 25,900 marine mammals, 6,000 sea turtles and tens of thousands of fish, among others.
- The Bay of Campeche oil spill: In June, 1979, the Bay of Campeche of the Gulf of Mexico saw the spill of around 140 million gallons oil- almost 10,000 to 30,000 barrels. The oil was discharged into the sea during a ten months period of time.
- Exxon Valdez Oil Spill: it’s the second largest oil spill in US waters in terms of the volume of oil discharged. Due to the accident which occurred in 1989, 10.9 million gallons of oil were spilled into Alaskan Coastline. As a result, the eco-system in the area was affected badly as it immediately killed over a lots of marine species including around 250,000 seabirds, almost 2,800 sea otters and 300 harbour seals, among others.
Water pollution by marine debris
Aquatic ecosystems are also threatened by solid wastes such as plastic, metals, cigarette buts and others. However, the principal solid pollutant of our water resources is plastic. In fact, 40,000 tons of plastics are currently floating on the oceans’ surface and that represents 80% of all trash floating in the oceans (46,000 pieces per square mile). These solid wastes present a real danger for aquatic life because they can be ingested by animals and cause their suffocation, starvation and death. According to the Office For Coastal Management, the marine debris are responsible for harming more than 800 different species of marine life.
The real problem with plastic is that its persistence in the environment for a very long time. That’s why the best options will be to reduce considerably our wastes and to use other materials that are biodegradable and eco-friendly.
The effect of ocean acidification on marine organisms
Ocean acidification is the decrease of pH of water surfaces due to the absorption of carbon emissions. Actually, seas absorb as much as a quarter of all man-made carbon emissions and the problem is rapidly worsening. It’s estimated that by the end of this century, if we keep pace with our current emissions practices, the surface waters of the ocean could be nearly 150 percent more acidic than they are now.
Marine ecosystems are deeply affected by these chemical alteration of water surfaces. For example, shellfish require calcium carbonate to build their shells and skeletons. But the ocean’s carbonate levels go down when acidity levels rise, threatening the survival of these animals. Bivalves are at the bottom of the food chain, so these effects ripple up to many fish, seabirds, and marine mammals. In addition, the increase of ocean acidity enhances the bleaching of coral reef and makes it harder for some types of fish to sense predators and preys.
