River health revealed in bird eggs!
Birds' eggs show just how serious a problem river pollution remains in the UK's former industrial heartlands, according to a new study.
Scientists analysed the eggs of Eurasian Dippers living in 33 rivers in South Wales, comparing the eggs of birds living along urban waterways with those of their rural peers. The city-dwellers' eggs contained large amounts of several harmful chemicals — in some cases four times higher than their country cousins, and approaching levels known to cause permanent damage.
Indeed, the team detected some of the highest levels of one particular class of pollutants ever recorded in songbirds. This means there could be risks not just to birds but also to people living nearby. The researchers say that testing bird eggs or blood samples could be a valuable addition to the methods water companies and regulators use to monitor river water quality, because of the way they illustrate wild organisms' real exposure to pollution.
The rivers of the Welsh valleys suffered severe pollution during the area's mining and industrial heyday; in the 1970s they were among Europe's most contaminated watercourses. Efforts to clean them up in recent decades have succeeded in cutting pollution from sources like factories, collieries and sewage works, aided by the decline of heavy industry.
Eurasian Dipper photo via Shutterstock.
Read more at Planet Earth Online.