Iconv failing to convert UTF-8 to ISO-8859-1



I have a technorati like website, and on some feeds I index I need to
convert the feed content from utf-8 to iso-8859-1.

However, on a few feeds, the conversion is failling bad.

See and example here:

This utf-8 string “enxergarem”

Generates a fail on Iconv when converting from utf-8 to iso-8859-1

Any ideas?