The vast ocean covering our planet is not only home to a diverse array of marine life but also victim to various forms of pollution. Among these, chemical pollution poses a significant threat to the magnificent creatures that inhabit the seas, particularly those at the top of the food chain, such as whales, dolphins and porpoises.
There is a common misconception that chemical contamination is diluted to the point of having no effect due to the vastness of the sea. Yet, chemicals with persistent or bioaccumulative properties tend to have higher concentrations in the marine environment than in freshwater, as well as having the longest-lasting effects.
There are some persistent organic pollutants, so-called POPs, people might have heard of, like polychlorinated biphenyls (PCBs), per- and polyfluoroalkyl substances (PFAS), bisphenol A (BPA) or polycyclic aromatic hydrocarbons (PAHs), but there are many more POPs which are less well known; and all reach the sea from various sources, including industrial activities, agricultural runoffs, oil spills, and improper disposal of waste.
Certain POPs have been banned or regulated under the Stockholm Convention, an international treaty that aims to protect human health and the environment by prohibiting, eliminating or restricting the global production and use of certain POPs.PCBs are a group of POPs which were utilised extensively within products such as electronic devices, paints, cements, sealants, adhesives, pesticide products, flame retardants and wood floor finishes before they were banned globally in 2004 under the Stockholm Convention. However, despite this ban, PCBs still leak into the environment through careless disposal of products containing PCBs and governmental failure to tackle the 14 million tonnes of contaminated material around the world.
Many POPs are highly soluble in fatty tissues such as blubber and tend to accumulate through the food chain. As whales and dolphins are long-lived, high on the marine food chain and tend to have a considerable amount of blubber, they are particularly vulnerable to such a build-up of POPs over time through consumption of contaminated fish and other marine life. In times of stress, for example when food is scarce, or the individual is pregnant or lactating, they break down their stores of blubber to provide them with an energy supply. Breaking down blubber in this way releases a flood of toxic POPs into their body which then can be transferred to a foetus or newborn.Studies have shown that exposure to certain POPs like PCBs and heavy metals (such as mercury) has severe impacts on specific species and populations of whales,dolphins and porpoises.
These impacts include cancers, cysts, reproductive impairment or failure, such as foetal death, abortion, difficult births or stillbirth, and disruption to hormone function with a higher risk in females who are reproducing for the first time. PCBs specifically have been linked to a weakened immune system, making these species more susceptible to diseases and infections, resulting in reduced population growth.
A decline in the number of whales and dolphins has detrimental effects on the entire ocean ecosystem. The cocktail effect caused by a mixture of POPs has, as yet, unknown consequences on these animals.
A report published today by Whale and Dolphin Conservation brings together what is known about the harmful effects of chemical pollution on these species, highlighting the threats and making recommendations for necessary changes.
To combat chemical pollution in the marine environment, it is crucial to address the root causes. Industries need to adopt cleaner production practices, and agricultural activities must follow responsible and sustainable practices to minimise the release of pollutants into water bodies.
Governments and regulatory bodies play a vital role in implementing and enforcing stringent regulations regarding chemical usage, waste disposal, and pollutant monitoring. By holding polluters accountable, we can reduce the impact of chemical pollution on marine life.
Continued research and monitoring programmes are crucial to better understand the effects of chemical pollution on marine species. This knowledge can guide policymakers and conservation organisations in implementing effective strategies for protecting our magnificent whales and dolphins and their habitats.
Raising awareness among the general public about the detrimental effects of chemical pollution on our one shared ocean and the lives of marine wildlife is essential. Through education and outreach programmes, people can make informed choices to reduce their own contribution to pollution, actively support conservation initiatives and put pressure on governments to implement binding legislation.
Pine Eisfeld-Pierantonio is Marine Pollution Coordinator for Whale and Dolphin Conservation (WDC).
Follow Pine on Twitter @Pindelinde and WDC on Twitter and LinkedIn @whalesorg
The opinions expressed in this blog are held by the authors and not necessarily those of the wider Link membership.
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