With no error checking or untainting,and assuming you know the names you want ahead of time (and heck, even if you don't, you can construct the list, it's just a little more work):

my @params_to_join = qw(foo bar baz);
my $Job = join ":", map {$q->param($_)} @params_to_join;
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Or, even more concisely:

my $Job = join ":", map {$q->param($_)} qw(foo bar baz);
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HTH

perl -e 'print "How sweet does a rose smell? "; chomp ($n = <STDIN>); 
+$rose = "smells sweet to degree $n"; *other_name = *rose; print "$oth
+er_name\n"'
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