Asked by: Amy Rhys-Davies, Cambridge
Even after passing through water treatment plants, small quantities of chemical compounds from cleaning products can find their way into rivers, ponds and lakes and have adverse effects on aquatic life. Phosphates in laundry and dishwasher detergent have a fertilising effect, triggering the widespread growth of algae that saps away the water’s oxygen, reducing biodiversity.
By reducing water tension, surfactants allow other pollutants in water bodies to be absorbed more easily by plants and animals. Many other compounds can be toxic to wildlife, or affect growth and reproduction, for instance by mimicking the effects of hormones in mammals and fish.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.