Can someone please help me with finding a website which gives me information on the environmental problems involving the disposal of batteries?

I've found the little section on section on Wikipedia, but it's sufficient to write a paragraph in my essay.

You might find some useful information on this site. It looks at the different types of batteries

http://www.batteryrecyclinguk.co.uk/

There is also some useful text in the EU directive on this topic:

http://eur-lex.europa.eu/LexUriServ/site/en/oj/2006/l_266/l_26620060926en00010014.pdf