my @spalte1;
my @spalte2;
#...
my @spalteN;

unique( \@spalte1, \@spalte2, ... \@spalteN );

sub unique {
    my( @cols ) = @_;

    my %u;
    for my $i ( reverse 0 .. $#{ $cols[0] } ) {
        if ( $u{ join( $;, map { $_->[$i] } @cols ) }++ ) {
            splice( @$_, $i, 1 ) for @cols;
        } # if
    } # for
} # unique