Organic compounds in surface and groundwaters in the surrounding of a Mexican geothermal reservoir; case study Los Humeros, Puebla

In this paper we evaluated if the Organic compounds (OC's) produced in the Los Humeros Geothermal Field (LHGF) could migrate to the surface and groundwaters in the surrounding areas; we report for the first time, the OC's of 2 maars, 24 springs, and 24 groundwater from sites surrounding the LHGF, in addition ten water/vapor condensates from the field were taken (all sampled in winter 2018). Using SPE-GC-MS, 141 OC's and 21 families were identified like alkanes, polyaromatics, sulfur-bearing, oxygen-bearing and halogen-bearing. Based on literature data, we assume that monoaromatics, alkanes and halogen-bearing could be some of the native families of the LHFG that migrate to the surrounding water bodies, without discarding an anthropogenic influence. In groundwater, 93 OC's and 19 families were identified. In the springs, 66 OC's grouped into 18 families were identified. In the case of the maars, 22 OC's and 10 families were identified. The most toxic polyaromatics identified in LHGF fluids are the heavy compounds pyrene and perylene which are naturally produced in the reservoir by combustion processes and carried to the surface by hydrothermal fluids at high temperatures. The results of this study do not prove a strong influence between the organic composition of condensates in the LHGF and the surrounding waters. How ever we provide new information to understand the dynamics of the LHGF. Furthermore, out of the scope of this study we could identify a strong anthropogenic influence on the sampling zone waters that can cause an environmental impact.

Automated summary

This study evaluated the migration of organic compounds (OC's) from the Los Humeros Geothermal Field (LHGF) to the surrounding surface and groundwaters. Through analysis of different water samples, various OC's were identified, suggesting the migration of certain compound families from LHGF to the surrounding water bodies, with a possible anthropogenic influence. Additionally, a strong anthropogenic influence on the sampling zone waters was found, indicating potential environmental impact.