Water Pollution: A Whale's Tale Of Toxic Woes

Water pollution is a pressing issue that poses a significant threat to sea animals, particularly whales. With an estimated 9.5 million metric tons of plastic waste entering the ocean annually, marine life is facing dire consequences. Whales, as one of the most iconic species in our planet's oceans, are severely impacted by plastic pollution, oil spills, and noise pollution. Marine debris, including discarded fishing gear, entangles and kills hundreds of thousands of whales, dolphins, and porpoises every year. Additionally, the ingestion of plastic leads to internal injuries and death, affecting over 240 wildlife species. Oil spills, both accidental and deliberate, have catastrophic effects on whales and other marine life, damaging their health and disrupting their habitats. Noise pollution, caused by human activities such as oil exploration and military exercises, interferes with whales' ability to navigate, communicate, and detect danger, driving them away from essential breeding and feeding grounds. The cumulative effects of these pollutants have far-reaching consequences for the health and survival of whale populations, highlighting the urgent need for global efforts to address water pollution and protect these majestic creatures.

Plastic ingestion and entanglement

Plastic Ingestion

Whales can accidentally ingest plastic while feeding on prey, or it can enter their digestive system from inside prey that has previously fed on plastic. In 2018, a sperm whale that stranded in Indonesia was found to have ingested over 13 pounds of plastic, including bags and flip-flops. Even deep-diving species like True's beaked whales have been found with plastic in their stomachs.

Microplastics, plastic pieces smaller than 5mm, are of particular concern for baleen whales, as these giant creatures can end up ingesting them along with krill or other prey while filter feeding. An average humpback whale will ingest around 9.3 billion microplastics in its lifetime.

Ocean plastic has been found to be an excellent surface for chemicals known as persistent organic pollutants (POPs) such as DDT to cling to, after entering the water as runoff, spills, or other waste. These pollutants can enter a whale's body when plastic is ingested and are sometimes stored within their blubber. Through bioaccumulation, species at the top of the food chain, like whales, are the most likely to accumulate the highest amounts of these chemicals. POPs have been found in humpback whales, sperm whales, pilot whales, and fin whales.

Plastic Entanglement

Whales can become physically entangled in plastic in the ocean, usually in the form of fishing nets and ropes. Entanglement in plastic can cause whales surface injuries, as well as extreme energy exertion needed to travel with the burden of debris dragging behind them, and these effects can sometimes be lethal. Every year, 300,000 whales, dolphins, and porpoises get accidentally entangled in nets and lines and die a slow and painful death through suffocation, starvation, or exhaustion.

Even microplastics, which are the most abundant debris floating in the marine environment, have been found in whales and their prey. These micro-pollutants can break down from sunlight and other environmental factors into invisible toxic chemical compounds, which then work their way up the marine food web and can disrupt the development and reproductive health of marine animals.

Oil spills

Whales can be exposed to oil through inhalation, ingestion, or swimming through it, which can lead to skin irritation, pneumonia, and other complications.

Mitigation strategies

During an oil spill, "hazing" methods are sometimes used to deter whales from the affected area. These include acoustic deterrent devices, pre-recorded killer whale calls, oikomi pipes, boat traffic, helicopters, and fire hoses. However, these methods are not always effective, and capture and rehabilitation of whales is improbable during a spill.

Noise pollution

Noise can also alter the behaviour of marine mammals. They may move away from the noise, adjust their activities to avoid noisy times, or increase their anti-predatory behaviour. For example, sonar has been observed to alter the feeding behaviour of endangered blue whales, causing them to stop feeding, swim faster, and move away from the sound source. This can have significant impacts on their individual fitness, foraging ecology, and population health.

To reduce noise pollution in the marine environment, policies are needed to mitigate propeller noise from ships and the sounds of sonar equipment, seismic air guns, pile-driving, and construction. Quieter technologies, such as alternatives to conventional pile-driving and air guns, should also be adopted. Additionally, implementing speed restrictions for ships can help reduce noise, as well as gas emissions and the risk of ship strikes.

Chemical pollution

One of the main issues with chemical pollution is the presence of 'forever chemicals', such as polychlorinated biphenyls (PCBs), which do not break down over time. These chemicals are absorbed by small fish, which are then eaten by larger fish, seals, and eventually whales. This process, known as biomagnification, results in the accumulation of toxins in the bodies of top predators like orcas. PCBs, for example, are stored in the fatty tissue (blubber) of whales and can lead to sterility and even death. In addition, whales may also be exposed to chemicals through oil spills, as they may ingest contaminated prey or inhale fumes.

Another group of toxic chemicals, known as persistent organic pollutants (POPs), can have harmful effects on the health of both humans and animals. These chemicals travel long distances through wind and water and persist in the environment for extended periods. POPs can cause reproductive issues, severe health problems such as cancer, and even death in whales and other marine mammals. Phthalates, a component of plastics, are also considered toxic and have been found in high concentrations in whales, dolphins, and porpoises in the Mediterranean Sea.

To address the issue of chemical pollution, global efforts have been made. For instance, the Stockholm Convention, signed by the UK and 90 other countries, aims to reduce or eliminate the production and use of POPs. Additionally, there have been calls for stricter regulations, improved waste management, and the banning of certain toxic chemicals to prevent further contamination of our oceans and protect whales and other sea creatures from the devastating effects of chemical pollution.

Sewage and industrial waste

The release of sewage into water bodies has been linked to a significant number of infectious diseases, including gastroenteritis, upper respiratory illnesses, diarrhoea, cholera, dysentery, typhoid, and hepatitis A. According to the World Health Organization and UNICEF, bathing in polluted seas causes approximately 250 million cases of such diseases annually. Sewage pollution also contributes to the growth of harmful algal blooms, which can produce neurotoxins that are dangerous to marine life, including whales.

Industrial waste, on the other hand, introduces a range of toxic chemicals into water bodies. One particularly dangerous group of chemicals is PolyChlorinated Biphenyls (PCBs), which were commonly used in building materials until a global ban was implemented in 2004. PCBs persist in the environment due to improper disposal and contaminated materials, accumulating in the food chain and reaching high concentrations in top predators such as whales. These toxins are stored in the fatty tissue (blubber) of whales and can lead to sterility and population decline.

Additionally, industrial activities can result in oil spills, which have devastating consequences for marine life. While large oil tanker spills often grab headlines, a significant portion of oil pollution comes from land-based sources such as factories, farms, and cities. Oil spills can directly harm whales by contaminating their prey, inhalation of fumes, or ingestion through swimming. Oil spills can also kill off smaller organisms that are part of the whales' food sources, indirectly affecting their survival.

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