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Does flushing condoms down the toilet pose a risk to aquatic ecosystems? An initial study published in Environmental Science: Processes & Impacts suggests that they don’t.
Filters at wastewater treatment plants are not fail-safe when it comes to removing condoms. Materials degrade en-route so smaller particles can sneak through filters and flooding can result in effluent bypassing treatment procedures completely.
— Condom derivative concentrations – Ouse and Derwent catchment
To investigate the scale of the problem, researchers in the UK initiated an anonymous survey quizzing people about how often they flushed condoms down the toilet. The survey, which is part of a wider study that is trying to understand the environmental impact of polymer-based materials and their degradation products, discovered that almost 3% of condoms bought were consigned to the sewers.
Survey data, along with information on screening efficiencies at sewage treatment plants, were put into a computer model of a river basin and its catchment area. This model estimated the amount of condom-derived material that should be present in environmental water. Condoms were then left to degrade in a simulated natural environment to reflect the quantity estimated to be present in environmental water. The resulting degradation mixture was sampled and used in ecotoxicity studies with the freshwater organisms, Daphnia magna and Chironomus riparius. Luckily for both species, the studies showed that the break-down products of condoms had no toxic effect in the concentrations predicted by the models.
Good news…I think? That’s not to say you should feel free to flush your condoms willy-nilly. Condoms, sanitary products and food waste such as oils cause major problems for waste water treatment (I’m thinking of the Delhi Commonwealth games in 2010), and we still need to understand how other species may fare. Bioaccumulation in the river food chain could also increase these products to physiologically relevant concentrations, as has been seen with other plastic derived compounds. If fish populations are hit hard enough by pollution, anglers may have to turn to alternatives and attempt to land the fabled two pound black ribbed nobbler.