Pollution Effects on Oceans and Marine Life

Marine pollutants are more n addition to ocean acidification, our seas and and polychlorinated biphenyls (PCBs), but easily defined by impact: Itheir wildlife are facing a grave threat from also some of life’s building blocks, such as any substance introduced the increased dumping and release of toxic nitrogen and phosphorous compounds. These into the oceans that has pollutants into the marine environment. What pollutants can enter our oceans through illegal undesired effects. are these pollutants and how do they affect the direct dumping of toxic industrial waste, or (photo: iStockphoto) seas? How is the IAEA involved with monitoring through harder-to-control natural processes these pollutants? such as wind, rain runoff and polluted rivers. Through careful monitoring and strict Which pollutants are affecting the regulations governments hope to control the seas? harmful pollutants that enter the seas. Defining what a pollutant is can be challenging How do heavy metals affect since the term applies to many substances in organisms? addition to toxic industrial by-products. Marine pollutants are more easily defined by impact: Although heavy metals like lead and mercury any substance introduced into the oceans that can kill an organism if a significant quantity has undesired effects. This broad definition is ingested in a short period of time, most includes heavy metals, such as lead and heavy metal poisoning affects sea life by mercury, and synthetic organic compounds generally reducing organisms’ longevity and like chlorinated pesticides, flame retardants their ‘recruitment’, or the organisms’ ability

24 | IAEA Bulletin 54-3-September 2013 to produce surviving offspring. Shortened they can be adequately treated to avoid risks life spans and reduced recruitment in and are used safely in accordance with good key organisms significantly weakens the practice. ecosystem, making it more vulnerable to other threats such as overfishing, climate change Sewage sludge can now be treated with or ocean acidification. Degradation of the gamma rays from a cobalt-60 source or with marine environment is often attributed to the an electron accelerator, which can kill the combination of these stressors rather than any pathogenic (disease-causing) agents in the single cause. sludge, such as bacteria, fungi or viruses. This nuclear application will enable the How do nitrogen and phosphorous release of sludge into the environment in a compounds affect organisms? safe manner. A pilot plant for sludge gamma irradiation is operating in India. The process Essential in supporting plants’ life and yields pathogen-free, dried sludge that can be growth, the natural elements nitrogen and beneficially used as manure in agriculture. The phosphorous are key components of fertilizers. field trials performed in Baroda confirmed that When too much fertilizer is applied to fields, the manure enhances crop yield and improves rainwater can wash excess nitrogen and soil conditions phosphorous into river systems and onwards to the sea. There, these nutrients can cause phytoplankton populations to explode, an event called a population ‘bloom’”. Toxic algal blooms can then transfer toxins to fish that in The IAEA Environment Laboratories use radioisotopes turn can be consumed as seafood. Sometimes to track and trace the sources of pollutants and in that this overfeeding, or ‘eutrophication’, can way help countries control their environmental impact. boost the population of some species to the detriment of others.

Increased algal blooms can produce oxygen How does the IAEA help? deficiencies in areas due to decomposition of the planktonic biomass, and create so called The IAEA helps its Member States use nuclear ‘dead zones’, anaerobic zones where normal technologies to monitor pollution on land and sea life cannot survive. in the sea. The IAEA Environment Laboratories use radioisotopes to track and trace the sources of pollutants and in that way help Where do pollutants go? countries control their environmental impact. When organisms ingest and retain more For example, the IAEA supported a study pollutants and toxins than they can excrete, of the effects of trace amounts of cadmium ‘bioaccumulation’ occurs. Through the (a toxic metal) on local fish and shellfish in food chain, pollutant concentrations tend Chile1. Experiments were designed to use the to increase in the bodies of top predators radiotracer cadmium-109 to measure how (biomagnification). Humans, at the top of the quickly the cadmium in mussels was released food chain, run a great risk of accumulating in order to understand the bioaccumulation of high concentrations of pollutants in their body this hazardous metal. tissues. Research conducted on top predators in the marine environment (large fish, seals Michael Madsen, IAEA Division of Public and seabirds) helps us in understanding the Information biomagnification process and to assess seafood safety. 1Investigations of marine ecotoxicological impacts using nuclear-based techniques. How can nuclear techniques mitigate www.iaea.org/monaco/page.php?page=2221 pollution? Domestic wastewater and the solids it produces after treatment can be dangerous to human health and the environment if not managed properly. At the same time, wastewater solids contain valuable organic matter and nutrients, which can enrich soil and may emerge as important resources provided

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