The following are useful websites (in no particular order)
http://www.hpa.org.uk/Topics/Radiation/UnderstandingRadiation/UnderstandingRadiationTopics/
The BBC website http://www.bbc.co.uk/news/health-12722435 contains a relatively good basic source of information on radiation risks. The word ‘relatively’ is used because the website claims that the “lowest level at which any … increase in cancer risk is clearly evident” is 100 mSv which is incorrect. There is a great deal of evidence of adverse effects well below this level.
http://www.usuhs.mil/afrri/outreach/pdf/doa_du_policy_07-022.pdf on DU
http://www.epa.gov/radiation/docs/402-f-06-061.pdf
http://books.nap.edu/books/030909156X/html/R1.html to download US BEIR VII
http://www.criirad.org/ (in French)
http://www.radioactivist.org/about.html
http://ec.europa.eu/energy/nuclear/index_en.htm
http://www.no2nuclearpower.org.uk/
http://www.ratical.org/radiation/
http://www.mclaughlincentre.ca/research/radiation.shtml
http://hpschapters.org/northcarolina/NSDS/210PoPDF.pdf for data on Po-210
http://www.cdc.gov/nceh/radiation/default.htm
http://orise.orau.gov/reacts/resources/radiation-faq.aspxhttp://www.cdc.gov/niosh/ocas/ocasirep.html
http://archive.greenpeace.org/nuclear/
http://baywood.com/books/BooksBySubject.asp?Subject=13
https://pubs.cancer.gov/ncipl/home.aspx
http://www.cordbloodbanking.com/
http://www.cordbloodguide.com/