This  volume  is  an  abridgement  of  a  substantial  work on water quality in the Americas produced by the Water Program of the InterAmerican Network of  Academies  of  Science  (IANAS).  This  work,  which  is  entitled  Water  Quality  in  the  Americas:  Risks and Opportunities, was co-authored by some 148  scholars  and  experts  including  the  members  of the IANAS Water Program and their associates. The  purpose  of  the  present  volume  is  to  provide  an accessible overview and summary of the larger document which totals over 600 pages. Unlike the larger  version  which  provides  descriptions  and  analyses of water quality problems on a country-by-country basis and several special chapters, this  volume  focuses  water  quality  problems  on  a  broader  hemispheric  basis.

While  examples  are  drawn  from  individual  countries,  the  intent  is  to  provide the reader with an overarching assessment of the water quality problems of the Americas and some of the means for addressing them.  In the 19th and early 20th centuries concerns about  water  resources  were  focused  mainly  on  the  adequacy  of  supplies  to  support  domestic,  industrial,  and  agricultural  activities.  With  the  advent  of  the  modern  era,  it  began  to  become  obvious that protection and maintenance of water quality is an essential part of maintaining supplies for different uses of water. Continuing declines in water quality frequently result in loss of available supplies as surely as drought.  The restoration and protection of water quality is complex and entails a variety of efforts ranging from the management of  watersheds  to  the  enactment  and  execution  of  water  laws  and  policies.

This  is  especially  true today as new and previously unknown contaminants  emerge,  often  before  their  impacts  on water and its uses can be adequately evaluated. Moreover,  it  is  now  understood  the  protection  of  ecosystems  and  the  production  of  environmental  services require careful management of water quality. Comprehensive monitoring of water quality  is  inadequate  in  most  of  the  Americas.  

Without  monitoring  it  is  difficult  to  assess  the scale  and  extent  of  a  water  pollution  problem and  similarly  difficult  to  know  whether  efforts to  improve  and  protect  water  quality  have  been  successful. Monitoring nominally requires public investment and yet the importance of it is obscure to members of the public and efforts to raise public revenues to support it are rarely successful.