Doctoral Dissertations

Keywords and Phrases

Anthropogenic impacts; Guatemala; Heavy Metals; Lake Izabal; Mining; Tilapia fish farms


”Water is essential for human subsistence. Stable freshwater supplies are needed as a source of food, drinking water, for transportation, recreation and economic development. Despite their recognized importance, anthropogenic activities have altered freshwater ecosystems around the world. Lake Izabal is the habitat for diverse aquatic species of flora and fauna, some of which are endemic and endangered. Its importance notwithstanding, anthropogenic activities developed in Lake Izabal’s catchment in recent years have compromised its status. This study used paleolimnological techniques to link past and recent anthropogenic activities such as mining operations and recent tilapia aquaculture. Relative abundances and concentrations of Pb, Zn, and Ni were measured in sediments from Lake Izabal. The results suggest that high Pb and Zn near the Polochic Delta correlates with mining between ~1945 and 1965 CE. The high Ni concentrations possibly indicate that recent Ni mining operations can be causing such increase, but Ni is not been widely distributed throughout the lake. The background metal levels reflected input also from natural erosion of bedrock. To assess the impact of tilapia cages, total nitrogen, total organic carbon, total phosphorus, and P-fractions were analyzed in 23 short sediment cores taken in 2017, 2018 and 2019. In general, nutrient (N, C and P) concentrations were higher in uppermost deposits of cores collected immediately beneath and near (within ~50 m) tilapia cages compared to concentrations in deposits farther away. The results provide evidence of contamination from these antropogenic activities, which potentially can be useful to policy-makers and national agencies in their remediation efforts and adequate environmental mangement of Lake Izabal”--Abstract, page iv.


Obrist-Farner, Jonathan
Oboh-Ikuenobe, Francisca

Committee Member(s)

Wronkiewicz, David J.
Hogan, John Patrick
Brenner, Mark


Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geology and Geophysics


This research was supported by Missouri University of Science and Technology and by a Geological Society of American Student Research Grant.

Research Center/Lab(s)

Center for Research in Energy and Environment (CREE)


Missouri University of Science and Technology

Publication Date

Fall 2020

Journal article titles appearing in thesis/dissertation

  • Natural and anthropogenic sources of lead, zinc, and nickel in sediments of Lake Izabal, Guatemala
  • Nutrient release from small-scale tilapia (Oreochromis niloticus) aquaculture: A case study from Lake Izabal, Guatemala


xi, 72 pages

Note about bibliography

Includes bibliographic references.

Geographic Coverage

Lake Izabal, Eastern Guatemala


© 2020 Elisandra Hernandez, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 11786

Electronic OCLC #



Dissertation Location