We use cookies to imporve your experience. By using our site, you consent to our cookie policy Learn more
arrow arrow_up breadcrumb-chevron-right breadcrumb-home dropdown-arrow-down loader GALogoWUNEP GALogo2018 GALogo2019 menu read-more-plus rrss-email rrss-facebook rrss-flickr rrss-instagram rrss-linkedin rrss-twitter rrss-vimeo rrss-youtube rrss_google_plus rrss_skype rrss_web pdf search share Completed In Process Ideas In Develpment Toogle Toogle Thumbnail View List View play close filter-collapse filter edit media_photo_library media_video_library graphics pictures videos collections next

Freshwater alkalinity: 1976-2008

Alkalinity is commonly used to indicate a water body’s capacity to buffer against acidity; that is, the ability to resist, or dampen, changes in pH. Thus, alkaline compounds in water, such as bicarbonates, carbonates, and hydroxides, lower the acidity of the water and increase the pH. Alkalinity (as CaCO3) was analysed for all sampling stations available at the continental level. Concentrations remained reasonably steady between the two decades for Africa, Asia, South America and Australasia, but significant increases were noted for European and North American rivers, which may indicate a shift towards reduced acidic impacts at the continental scale. Overall, during the last 30 years , alkalinity has decreased in North America and Europe, but has significantly increased in Asia. Examination of the outflow stations in 82 monitored river basins indicate a decrease in bicarbonate concentrations between the two decades , in the northern latitudes, including North America, Europe and Asia. For the period 1976-1990, European rivers displayed the highest concentrations of calcium at a continental level, with concentrations varying between 2 mg and 50 mg per litre for major rivers. Comparing the two decades, observations of surface water showed an increase in calcium concentrations in the Laurentian shield region of North America, and in the rivers of the north central European region.

Year: 2009

From collection: Vital Water Graphics 2

Cartographer: Philippe Rekacewicz, February 2006

Graphics included in same album

View all media

Publications it appears in

View all publications