# Environmental Impact of Corn Tortilla Production: A Case Study
## 3 Results and Discussion
### LCIA: National Dimensioning
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Impact Category** & **Units** & \begin{tabular}{c} **Process with the** \\ **Greatest Impact** \\ \end{tabular} & \begin{tabular}{c} **Enissions/inputs with the** \\ **Greatest Impact** \\ \end{tabular} & \
\begin{tabular}{c} **Functional Unit** \\ **Variation \({}^{\star}\)** \\ \end{tabular} &
\begin{tabular}{c} **National Environmental** \\ **Impact** \\ \end{tabular} \\ \hline CC & kg CO\({}_{2}\) eq & Corn Production & CO\({}_{2}\), N\({}_{3}\)O & 4.19 \(\times 10^{-18}\) kg CO\({}_{2}\) eq & 10\% & 3.09 \(\times 10^{17}\) \(\mathrm{CO_{2}}\) eq \\ \hline OD & kg CC-11 eq & Cooling & Hale 1031 & 7.25 \(\times 10^{-8}\) kg CC-11 eq & 80\% & 5.36 \(\times 10^{-11}\) CC-11 eq \\ \hline TA & kg CO\({}_{2}\) eq & Corn Production & NH\({}_{3}\) & 1.83 \(\times 10^{-2}\) kg SO\({}_{2}\) eq & 2\% & 1.35 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) eq \\ \hline PE & kg PE eq & Corn Production & PO\({}_{4}\), \({}^{3}\) & 1.04 \(\times 10^{-5}\) kg PE eq & 5\% & 7.71 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) eq \\ \hline ME & kg N eq & Corn Production & NH\({}_{3}\) & 7.78 \(\times 10^{-4}\) kg N eq & 20\% & 5.75 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) eq \\ \hline HT & kg I-CDB eq & Corn Production & Sb & 1.98 \(\times 10^{-2}\) kg I-4-DB eq & 60\% & 1.47 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) I-4-DB eq \\ \hline POP & kg NMVOC & Raw material & N\({}_{3}\)O\({}_{3}\) & 9.95 \(\times 10^{-4}\) kg NMVOC & 10\% & 7.36 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) \\ \hline PMF & kg PM10 & Corn Production & NH\({}_{3}\) & 2.78 \(\times 10^{-3}\) kg PM10 eq & 20\% & 2.06 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) eq \\ \hline TET & kg I-4-DB eq & Corn Production & Chloryryrilos, & 9.00 \(\times 10^{-5}\) kg I-4-DB eq & 12\% & 6.65 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) I-4-DB eq \\ \hline FET & kg I-4-DB eq & Corn Production & Be Chloryrilos & 4.50 \(\times 10^{-4}\) kg I-4-DB eq & 29\% & 3.33 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) I-4-DB eq \\ \hline MET & kg I-4-DB eq & Corn Production & Cu, Ni & 3.91 \(\times 10^{-4}\) kg I-4-DB eq & 29\% & 2.89 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) I-4-DB eq \\ \hline IR & kkq U235 & Cooking & \({}^{13}\)C & 2.73 \(\times 10^{-2}\) kg U235 eq & 5\% & 2.02 \(\times 10^{37}\) \(\mathrm{\SIUnitSymbolMicro}\) I-235 eq \\ \hline ALO & m\({}^{2}\) year & Corn Production & Arable land & 4.02 \(\times 10^{-2}\) m\({}^{2}\) year & 14\% & 2.97 \(\times 10^{2}\) m\({}^{2}\) year \\ \hline ULO & m\({}^{2}\) year & Corn Production & - & 1.05 \(\times 10^{-2}\) m\({}^{2}\) year & 24\% & 7.74 \(\times 10^{2}\) m\({}^{2}\) year \\ \hline NLT & m\({}^{2}\) & Corn Production & - & 5.19 \(\times 10^{-2}\) m\({}^{2}\) & 168\% & 3.83 \(\times 10^{2}\) m\({}^{2}\) \\ \hline WD & m\({}^{2}\) & Corn Production & Imrigation water & 1.87 \(\times 10^{2}\) m\({}^{2}\) & 15\% & 1.39 \(\times 10^{2}\) m\({}^{2}\) \\ \hline MRD & kg FE eq & Corn Production & Cu & 1.91 \(\times 10^{-3}\) kg FE eq & 23\% & 1.41 \(\times 10^{17}\) FE eq \\ \hline FD & kg oil eq & Corn Production & Raw oil & 1.97 \(\times 10^{-14}\) kg raw oil eq & 16\% & 1.46 \(\times 10^{17}\) \(\mathrm{\SIUnitSymbolMicro}\) I-4-D-eq \\ \hline \hline \end{tabular} \({}^{\star}\) Values less than 30% of the coefficient of variation are considered reliable for the analysis.  
\end{table} 
Table 13: Impacts of tortilla production in Mexico. Another indicator of environmental impact widely used is the water footprint. In this study it was considered as the category of WD. Table 14 shows the water footprint of some of the foods consumed by Mexicans.