open my $source,'-|',"bash /tmp/wrapper.sh" or die "$!";

my $dump= do { local $/; <$source>};

my $VAR1;

eval $dump;

print $VAR1->{MONK};  #> jfroebe
[download]

lanx@nc10-ubuntu:/tmp$ cat wrapper.sh 
. /tmp/src.sh
perl -MData::Dumper -e' print Dumper \%ENV'

lanx@nc10-ubuntu:/tmp$ cat src.sh 
export MONK=jfroebe

lanx@nc10-ubuntu:/tmp$
[download]

Thats an extremely stable approach, I can't think of a way to make it break! =)

you could even try to generate the code from wrapper.sh dynamically on the fly, hence avoiding any security/dependencies issues.

UPDATE

> you could even try to generate the code from wrapper.sh dynamically on the fly

works! =)

my $bashcode=<<'_bash_';
. /tmp/src.sh;
perl -MData::Dumper -e "print Dumper \%ENV";
_bash_


open my $source, '-|', qq{bash -c '$bashcode'} or die "$!";

my $dump= do { local $/; <$source>};

my $VAR1;

eval $dump;

print $VAR1->{MONK};  #> jfroebe
[download]

UPDATE

far less code, same result

my $bashcode=<<'__bash__';
. /tmp/src.sh;
perl -MData::Dumper -e 'print Dumper \%ENV';
__bash__

my $VAR1;
eval qx{bash -c "$bashcode"};

print $VAR1->{MONK};  #> jfroebe
[download]