1. Introduction
Environmental risk is the quantitative or qualitative evaluation of the danger of an adverse impact on the environment—which refers to the probability of the occurrence of an unfavorable situation that may lead to the destruction of ecosystems, alongside the disappearance or gradual deterioration of biodiverse populations, loss of quality of life and natural resources, and an impact on energy—due to the economic activity in a certain area [
1]. Anthropogenic activities have caused the overexploitation of natural resources, resulting in biodiversity loss in ecosystems worldwide [
2]. Another significant environmental concern affecting these ecosystems is accidental or chronic oil pollution [
3]. In 2010, the largest oil spill in United States history that occurred on the coast of the Gulf of Mexico caused one of the most significant environmental disasters in history [
4]. In 2018, the Lizama 158 well located in the municipality of Barrancabermeja, Santander, Colombia, presented an oil outcrop, which caused, according to official figures, the deaths of 2,442 animals and affected 5,507 trees [
5]. In Colombia, the operational risk in the hydrocarbon transportation phase is mainly due to repetitive actions carried out by third parties, such as external fraud, fortuitous events, and terrorist acts, which can lead to the collapse of sensitive ecosystems [
6,
7,
8].
The concept of risk pertains to something uncertain, tied to random chance and potentiality, regarding events that have not yet occurred. It is abstract, complex, and can only exist in the future. Recent efforts to assess disaster risk for management purposes have revolved around calculating the potential economic, social, and environmental impacts of a physical event at a specific location and time. However, there has been a lack of comprehensive conceptualization of risk; instead, fragmentation has prevailed as different disciplinary approaches estimate or calculate risk separately. Achieving an interdisciplinary estimation of risk requires consideration not just of projected physical damage and casualties or economic losses but also of social dynamics along with organizational and institutional aspects [
9].
A global bibliographic review was conducted followed by a specific focus on Colombia to assess the ecological impact of technological events in the oil and gas industry on the environment. The initial findings reveal that environmental disasters resulting from hydrocarbon project activities, particularly oil spills, have had significant negative effects on marine ecosystems [
10,
11,
12,
13,
14,
15], including on corals, benthic organisms, fish, mollusks, birds, plankton, mangroves, marine mammals, and reptiles. The consequences range from obstructing the sunlight necessary for photosynthesis to contaminating the food chain and reducing biodiversity [
16,
17,
18,
19,
20,
21]. For Colombia, only a spill that occurred in Cabo Manglares in the department of Nariño in 1976 [
22] was found, where the sinking of the Tanker St. Peter caused an oil leak, impacting the fishing industry and mangroves in the Tumaco municipality. While ocean spills have catastrophic effects, they rarely occur, especially in Colombia. However, from 1980 to 2020, over 2,800 terrorist attacks on oil infrastructures led to more than 3.7 million barrels of hydrocarbons spilling into the environment. This has impacted the soil quality and various ecosystems, including surface waters, flora, fauna (including birds, mammals, and reptiles), amphibians, and fish [
8]. Therefore, terrorist attacks are the major hazard for oil spills in Colombia [
8,
23,
24].
Vulnerability can be defined as an internal risk factor of a subject or system exposed to a hazard, corresponding to its intrinsic predisposition to be affected or susceptible to suffering damage [
9]. Ecological vulnerability in this study refers to the predisposition or susceptibility of the environment to be affected or suffer damage in case of an oil spill. The susceptibility of ecosystems, flora, and fauna to be affected initially depends on the volume and characteristics of the oil. However, ecosystems at risk may vary in their levels of vulnerability because oil sensitivity is inherent to the environment, which may be less or more sensitive depending on its characteristics [
25,
26,
27,
28]. Ecological vulnerability is a term used to describe how easily a specific system can change due to internal or external disturbances, reflecting its sensitivity and lack of adaptation capacity. Researchers believe that vulnerability consists of three elements: exposure, sensitivity, and adaptive capacity. Exposure measures a system's susceptibility to environmental and social stresses. The value of vulnerability determines the potential degree of system damage under the influence of accidents, while sensitivity reflects the unit's response to stressors [
29,
30,
31,
32,
33,
34,
35,
36].
A holistic approach to risk assessment encompasses risk from a complete viewpoint. This involves considering the potential ecological damage directly related to hazard events, as well as understanding how non-hazard-dependent factors, such as social, economic, and environmental elements, exacerbate existing ecological risk conditions in terms of anticipatory capacity, resistance, response, and recovery capabilities [
37]. Based on the holistic approach for the case of urban seismic risk evaluation and evaluating risk from a holistic perspective to improve resilience at a global level [
37,
38,
39], we define environmental risk as the interaction between hazard, exposure, and vulnerability, where hazard typically pertains to ecological impacts resulting from oil spill events. Exposure indicates the susceptibility of the flora, fauna, and ecosystems to be damaged (ecological vulnerability directly associated with oil spill events), along with underlying non-oil-spill-dependent factors that exacerbate existing risk conditions due to a lack of capacity to anticipate, resist, respond to, or recover from adverse impacts and environmental fragility (
Figure 1). The main objective of this paper was to develop a holistic methodology to evaluate the environmental risk associated with projects in Colombia's hydrocarbon sector.
3. Results
A case study was conducted to evaluate the proposed methodology in an oil pipeline between the municipalities of Maní in the department of Casanare and Puerto Gaitán in the department of Meta, Colombia (
Figure 7).
A scenario was initially defined, assuming the worst case of a catastrophic rupture in the pipeline at one of its initial points. After determining the oil spill volume, the ArcHydro Tools plugin in the ArcMap software was used to determine the oil spill routes based on slopes derived from a digital elevation model of the study area. This initial stage helped us understand the overall context of the risk scenario, enabling us to proceed with its evaluation. The damaged area variable corresponds to the volume of spilled barrels, specifically 907 BBL, according to the quantitative risk assessment. We consolidated data on individuals affected by previous oil spills and consulted expert biologists to determine the affected fauna variable. As for the affected land cover variable, we determined the area in hectares of main land covers that would be impacted by analyzing modeled spill routes. In terms of ecological impact, we referred to environmental management zoning developed by the company based on environmental impact assessment. Our evaluations and ratings for each variable are presented in
Table 4. Assessing individual areas affected by spills divided according to land cover was essential within this specific risk scenario. The ecological risk factor for each variable, as shown in
Table 5, was obtained according to the sigmoidal functions described above. The spatial distribution of ecological risk derived from this classification is presented in
Figure 8. The environmental disaster risk index was determined via a multi-criteria analysis, which involved analyzing factors related to identification, reduction, management, and financial protection against environmental risks. The index qualification was made in a participatory workshop with the company in charge. The response time was determined based on historical emergency response data in the country, indicating that it can range from hours to more than two months depending on the spill volume and geophysical conditions. The army conflict incidence index was assessed as medium-low for our study area. Finally, the ecological resilience assessment process considered land cover and expert input regarding post-disaster ecosystem recovery timelines. Details about the variables are presented in
Table 6. The aggravating coefficients for each impacted land cover are shown in
Table 7 using the previously described sigmoidal functions.
Figure 9 illustrates the spatial distribution. Finally, the holistic environmental risk index is shown in
Table 8.
4. Discussion and Conclusions
This is the first time a holistic approach has been used to evaluate environmental risk in hydrocarbon projects. This evaluation allowed us to determine, at the Colombian level, which factors do not depend on the spill that increase or decrease the risk. During the workshop held with the company in the case study, it was observed that although the company was aware of its shortcomings, it was not aware that these shortcomings increased the environmental risk. Conducting a self-assessment of its performance in the risk management of environmental disasters allowed the company to identify improvement actions, clarifying that risk reduction measures must be identified using integrated models and comprehensive analysis [
37].
This study presented a conceptual framework and a multidisciplinary assessment model for environmental risk analysis in the oil and gas industry in Colombia and introduced the holistic environmental risk index. This study's findings show that while companies in the industry are aware of their shortcomings, there is a lack of awareness regarding how these shortcomings contribute to increased environmental risk. The armed conflict in Colombia has a significant impact on environmental risk, particularly affecting the most sensitive ecosystems with high levels of risk.
These findings have profound potential to assist companies in improving their processes and prioritizing actions to reduce risks. They also emphasize the need to intensify efforts to resolve armed conflict as a strategy for reducing environmental risk at the national level, while highlighting the importance of mitigation measures for vulnerable ecosystems.
This study presented an innovative approach to assessing environmental risks in hydrocarbon projects from both practical and theoretical perspectives. This groundbreaking assessment identified critical factors beyond oil spills influencing environmental risk and provides a solid basis for informed decision making on risk management. However, like any rigorous evaluation, this initial methodology has uncertainties; therefore, it is recommended to conduct further workshops with different sector companies to assess additional descriptors or modifying factor weights. This collaborative approach will help refine the HERI index and promote greater awareness toward more effective sustainable management actions in Colombia's oil and gas industry.
Author Contributions
Conceptualization, M.A.D.V. and D.A.R.B.; methodology, M.A.D.V. and D.A.R.B.; validation, M.A.D.V., D.A.R.B., and C.P.G.R; formal analysis, M.A.D.V. and D.A.R.B.; M.A.D.V., D.A.R.B., and C.P.G.R.; data curation, M.A.D.V., D.A.R.B., and C.P.G.R; writing—original draft preparation, M.A.D.V. and D.A.R.B; writing—review and editing, C.P.G.R.; visualization, M.A.D.V.; supervision, C.P.G.R. All authors have read and agreed to the published version of the manuscript.