lots of posts in the keris forum. a search on 'arsenic' or it's indonesian name 'warangan' would be informative. the chemical treatment is followed by a wash in warm soapy water, so the risk of picking up any arsenic is minimal. best not to lick the blade tho.
the daggers made from spearpoints are fairly common.
mine is not quite as decorative as yours.
see also: lading terus at
http://old.blades.free.fr/