\begin{table}%T8
  \caption{\label{table:radio:ab}Ionic and total abundances of N, Ne, S and Ar derived as
    indicated in Sect.~\ref{sect:radio:abun}.}
  %\centerline
{
    \begin{tabular}[h]{lccccccc} 
    \hline \hline \\[-5pt]
    & \multicolumn{3}{c}{Nitrogen ($\times 10^{-4}$)} & & 
      \multicolumn{3}{c}{Neon ($\times 10^{-4}$)} \\
    \cline{2-4} \cline{6-8} \\[-1pt]
    \multicolumn{1}{c}{Source} &
    \multicolumn{1}{c}{N$^+$/H} & 
    \multicolumn{1}{c}{N$^{++}$/H} & 
    \multicolumn{1}{c}{N/H} & &
    \multicolumn{1}{c}{Ne$^+$/H} & 
    \multicolumn{1}{c}{Ne$^{++}$/H} & 
    \multicolumn{1}{c}{Ne/H} \\[5pt] \hline \\[-5pt]
IRAS 01045&         $\Diamond$ &        $\Diamond$  &        $\Diamond$&&
            0.29 $\pm$   0.10 &  0.08 $\pm$   0.02 &  0.37 $\pm$   0.12\\
IRAS 10589&  0.50 $\pm$   0.18 &  0.19 $\pm$   0.06 &  0.69 $\pm$   0.23&&
            1.16 $\pm$   0.24 &  0.14 $\pm$   0.03 &  1.30 $\pm$   0.26\\
IRAS 11143&  0.09 $\pm$   0.04 &  0.28 $\pm$   0.07 &  0.37 $\pm$   0.11&&
            0.38 $\pm$   0.08 &  0.76 $\pm$   0.15 &  1.14 $\pm$   0.22\\
IRAS 12063&           $<$0.24 &  0.26 $\pm$   0.09 &           $<$0.59&&
            0.36 $\pm$   0.07 &  0.31 $\pm$   0.06 &  0.67 $\pm$   0.13\\
IRAS 12073&           $<$0.06 &  0.21 $\pm$   0.07 &  0.21 $\pm$   0.07&&
            0.17 $\pm$   0.04 &  0.45 $\pm$   0.09 &  0.62 $\pm$   0.13\\
IRAS 12331&  0.44 $\pm$   0.16 &  0.35 $\pm$   0.11 &  0.79 $\pm$   0.27&&
            1.04 $\pm$   0.21 &  0.32 $\pm$   0.06 &  1.36 $\pm$   0.27\\
IRAS 15384&  0.82 $\pm$   0.30 &  0.39 $\pm$   0.13 &  1.21 $\pm$   0.43&&
            1.12 $\pm$   0.22 &  0.15 $\pm$   0.03 &  1.27 $\pm$   0.26\\
IRAS 15502&  0.63 $\pm$   0.24 &  0.28 $\pm$   0.08 &  0.91 $\pm$   0.32&&
            0.54 $\pm$   0.13 &  0.05 $\pm$   0.01 &  0.59 $\pm$   0.14\\
IRAS 16128&  0.49 $\pm$   0.18 &  0.36 $\pm$   0.11 &  0.85 $\pm$   0.29&&
           ~0.40 $\pm$ 0.07$^\dagger$ & ~0.10 $\pm$ 0.02$^\dagger$ &
           ~0.50 $\pm$ 0.08$^\dagger$\\
IRAS 17160&  0.50 $\pm$   0.18 &  0.15 $\pm$   0.04 &  0.65 $\pm$   0.22&&
            0.54 $\pm$   0.12 &  0.04 $\pm$   0.01 &  0.59 $\pm$   0.13\\
IRAS 17221&  1.18 $\pm$   0.42 &  0.19 $\pm$   0.06 &  1.38 $\pm$   0.48&&
            1.52 $\pm$   0.30 &  0.03 $\pm$   0.01 &  1.54 $\pm$   0.30\\
IRAS 17279&  1.52 $\pm$   0.50 &  0.35 $\pm$   0.08 &  1.87 $\pm$   0.59&&
            2.04 $\pm$   0.43 &  0.06 $\pm$   0.03 &  2.09 $\pm$   0.46\\
IRAS 18032&  1.78 $\pm$   0.87 &  0.31 $\pm$   0.11 &  2.09 $\pm$   0.99&&
            2.09 $\pm$   0.42 &           $<$0.02 &  2.09 $\pm$   0.42\\
IRAS 18479&           $<$0.25 &  0.05 $\pm$   0.02 &          $<$0.32 &&
            0.45 $\pm$   0.09 &  0.08 $\pm$   0.02 &  0.53 $\pm$   0.11\\
IRAS 19442&            $\flat$ &            $\flat$ &           $\flat$ &&
                     $<$2.78 &           $<$0.03 &           $<$2.81\\
IRAS 19598&           $<$0.12 &  0.05 $\pm$   0.02 &          $<$0.19 &&
            0.22 $\pm$   0.04 &  0.21 $\pm$   0.04 &  0.43 $\pm$   0.08\\
DR21     &           $<$0.45 &           $<$0.10 &          $<$0.55 &&
            0.86 $\pm$   0.17 &  0.10 $\pm$   0.04 &  0.96 $\pm$   0.22\\
IRAS 23133&  0.39 $\pm$   0.14 &           $<$0.06 &  0.39 $\pm$   0.14&&
            0.87 $\pm$   0.17 &           $<$0.01 &  0.87 $\pm$   0.17
\\[5pt] \hline \\[-3pt]
   &\multicolumn{3}{c}{Sulphur ($\times 10^{-5}$)} & & 
    \multicolumn{3}{c}{Argon ($\times 10^{-6}$)} \\
    \cline{2-4} \cline{6-8} \\[-1pt]
    \multicolumn{1}{c}{Source} &
    \multicolumn{1}{c}{S$^{++}$/H} & 
    \multicolumn{1}{c}{S$^{+3}$/H} & 
    \multicolumn{1}{c}{S/H} & &
    \multicolumn{1}{c}{Ar$^+$/H} & 
    \multicolumn{1}{c}{Ar$^{++}$/H} & 
    \multicolumn{1}{c}{Ar/H} \\[5pt] \hline \\[-5pt]
IRAS 01045&  0.10 $\pm$   0.05 &           $<$0.19 &           $<$0.34&&
                     $<$0.29 &           $<$0.64 &            $<$0.93\\
IRAS 10589&  0.78 $\pm$   0.17 &  0.14 $\pm$   0.07 &  0.92 $\pm$   0.24&&
            1.34 $\pm$   0.16 &  1.71 $\pm$   0.24 &  3.06 $\pm$   0.40\\
IRAS 11143&  0.75 $\pm$   0.18 &  0.89 $\pm$   0.36 &  1.64 $\pm$   0.54&&
                     $<$0.11 &  1.92 $\pm$   0.27 &           $<$2.30\\
IRAS 12063&  0.29 $\pm$   0.07 &  0.60 $\pm$   0.29 &  0.89 $\pm$   0.35&&
            0.27 $\pm$   0.04 &  1.82 $\pm$   0.26 &  2.08 $\pm$   0.29\\
IRAS 12073&  0.26 $\pm$   0.06 &  1.37 $\pm$   0.68 &  1.64 $\pm$   0.74&&
            0.07 $\pm$   0.03 &  1.75 $\pm$   0.23 &  1.83 $\pm$   0.26\\
IRAS 12331&  0.91 $\pm$   0.20 &  0.23 $\pm$   0.10 &  1.14 $\pm$   0.30&&
            1.04 $\pm$   0.16 &  3.10 $\pm$   0.59 &  4.15 $\pm$   0.75\\
IRAS 15384&  0.53 $\pm$   0.12 &  0.14 $\pm$   0.06 &  0.66 $\pm$   0.18&&
            1.80 $\pm$   0.23 &  1.86 $\pm$   0.32 &  3.66 $\pm$   0.55\\
IRAS 15502&  0.14 $\pm$   0.03 &  0.02 $\pm$   0.01 &  0.15 $\pm$   0.04&&
            1.46 $\pm$   0.21 &  0.78 $\pm$   0.16 &  2.24 $\pm$   0.37\\
IRAS 16128& ~0.20 $\pm$ 0.05$^\dagger$ & ~0.03 $\pm$ 0.01$^\dagger$ &
           ~0.24 $\pm$ 0.06$^\dagger$ &&
          ~1.37 $\pm$ 0.12$^\dagger$ & ~0.62 $\pm$ 0.14$^\dagger$ &
           ~1.99 $\pm$ 0.25$^\dagger$\\
IRAS 17160&  0.22 $\pm$   0.05 &           $<$0.03 &  0.22 $\pm$   0.05&&
            1.54 $\pm$   0.22 &  0.86 $\pm$   0.22 &  2.41 $\pm$   0.43\\
IRAS 17221&  0.64 $\pm$   0.15 &  0.02 $\pm$   0.01 &  0.66 $\pm$   0.16&&
            2.83 $\pm$   0.34 &  1.27 $\pm$   0.25 &  4.10 $\pm$   0.59\\
IRAS 17279&  0.67 $\pm$   0.14 &           $<$0.03 &  0.67 $\pm$   0.14&&
            4.66 $\pm$   0.63 &  0.82 $\pm$   0.25 &  5.48 $\pm$   0.88\\
IRAS 18032&  0.76 $\pm$   0.19 &           $<$0.01 &  0.76 $\pm$   0.19&&
            4.25 $\pm$   0.57 &  0.77 $\pm$   0.15 &  5.02 $\pm$   0.72\\
IRAS 18479&  0.17 $\pm$   0.08 &           $<$0.19 &           $<$0.44&&
            0.37 $\pm$   0.05 &           $<$0.31 &           $<$0.73\\
IRAS 19442&  0.42 $\pm$   0.10 &           $<$0.06 &           $<$0.58&&
                     $<$6.66 &           $<$0.47 &           $<$7.17\\
IRAS 19598&  0.10 $\pm$   0.03 &  0.21 $\pm$   0.12 &  0.31 $\pm$   0.16&&
            0.24 $\pm$   0.03 &  0.66 $\pm$   0.09 &  0.90 $\pm$   0.12\\
DR21     &  0.20 $\pm$   0.04 &           $<$0.01 &  0.20 $\pm$   0.04&&
            1.68 $\pm$   0.25 &  0.40 $\pm$   0.10 &  2.08 $\pm$   0.35\\
IRAS 23133&  0.48 $\pm$   0.15 &  0.04 $\pm$   0.02 &  0.51 $\pm$   0.18&&
            2.54 $\pm$   0.31 &  0.70 $\pm$   0.10 &  3.24 $\pm$   0.40
\\[3pt] \hline 
    \end{tabular}}
    \smallskip
{$^\Diamond$ No LWS observation available. $^\dagger$ No extinction was derived towards this source (see Table~\ref{table:radio:ext}); 
consequently, this abundance is not corrected from extinction.
$^\flat$ No \OIII\ density was calculated for this 
source \citep[see][]{martin:paperii}.
}
\end{table}