Soil is one of the most sensitive and vulnerable receiving environments for pollution. This condition is due to its role as a support for the development of life and human activities, as well as its interactions with surface water, groundwater and the atmosphere itself.
The environmental impact caused by the site contamination depends on the capacity of interactions with soil and water, as well as the physicochemical and biological conditions of the environment, which can change the state of the contaminants. characterization of a contaminated site It allows us to understand the hydrology of the soil and the physical, chemical and biological properties of the soil that influence the migration of substances and their distribution between the different phases (particles, air and water); likewise, knowledge of these properties allows us to properly select the most appropriate remediation technique.
What is contaminated soil?
The concept of contaminated site is defined by the LGPGIR as: place, space, soil, body of water, installation or any combination of these that has been contaminated with materials or waste that, due to their quantities and characteristics, may represent a risk to human health, living organisms and the use of people's goods or property.
Soil is a non-renewable natural resource, and is of vital importance to sustain life and the economic activities of a country. Soil performs several functions and uses: it acts as a regulator of the water cycle and biogeochemical cycles; it is the filtering medium for the water that recharges aquifers and, therefore, their protective layer; it houses a great diversity of organisms, which implies that the soil contains important genetic reserves; it is the space for agricultural, livestock, forestry and recreational activities; it is the basis for the construction of civil works; and it houses part of the cultural wealth.
What causes it?
The contamination of sites in Mexico has been caused by various anthropogenic activities, some of which are:
a) Mining activities. They have generated large quantities of tailings and slag, much of which was improperly disposed of before environmental regulation began in Mexico. The leaching of this waste contaminates the soil and potentially the water.
b) Hydrocarbon sector activities. It has generated contamination by hydrocarbons and other types of potentially toxic substances that have damaged soil and bodies of water.
c) Agricultural activities. The use of agrochemicals in agricultural activities and inappropriate practices have impacted not only the soils in the areas where they are applied, but can also affect rivers, lagoons and even coastal areas.
d) Industrial activities. The production of consumer goods has generated sources of contamination due to the improper handling of hazardous materials and all types of waste.
e) Service facilities . Gasoline service stations, vehicle repair shops, railway stations and facilities, bus terminals and airports, among others, have generated soil and groundwater contamination resulting from leaks in containers of hazardous materials; continuous spills of lubricants; organic solvents, or other types of substances, as well as inadequate practices in their management.
f) Use of wastewater in irrigation of agricultural fields. The use of these waters for irrigating agricultural crops causes soils and crops to become contaminated with chemical waste from industrial and municipal discharges.
g) Irregular disposal of waste (open air). These sites are the site of improper disposal of urban solid waste, which may be mixed with hazardous waste and whose leaching contaminates the soil.
Who is responsible?
Those responsible for the remediation of a site contaminated with hazardous materials or waste are:
a) Natural or legal persons who, directly or indirectly, contaminate a site or cause damage or impact on the environment;
b) Persons responsible for activities related to the generation and management of hazardous materials and waste that have caused the contamination of sites with these, and
c) Owners or possessors of privately owned land and holders of concession areas whose soils are contaminated.
When the federal entities own land whose soils are contaminated, they are also responsible for their remediation. However, federal entities do not always have the technical or economic capacity to carry out remediation (e.g., develop environmental liability remediation programs and executive projects).
SEMARNAT can participate in the remediation of a site contaminated with hazardous materials or waste that represents a risk to the environment and health when:
a. In the case of a contaminated site being declared abandoned;
b. It has been expropriated for reasons of public utility;
c. A remediation declaration has been issued by the Federal Executive;
d. The site is owned by a federal entity or municipality, or
e. Remediation has been ordered by federal mandate or through an international arbitration award.
This participation of SEMARNAT does not imply the substitution of responsibilities for the remediation of the site. SEMARNAT, through DGGIMAR, in coordination with state and municipal governments, has participated in actions and invested public resources for the remediation of contaminated sites considered environmental liabilities since 2003.
What is contaminated site remediation?
In Mexico, the remediation of contaminated sites refers to actions aimed at restoring ecosystems and natural elements affected by pollutants to their original or base state. According to the Federal Environmental Responsibility Law (LFRA) , remediation is part of the repair of damage caused to the environment, which includes the restoration, reestablishment, treatment and recovery of habitats, ecosystems and natural resources that have been affected.
In addition, the General Law for the Prevention and Comprehensive Management of Waste (LGPGIR) It also mentions remediation as one of the responsibilities to mitigate the effects of contaminants and ensure that the risks associated with contamination in soil and water are eliminated or reduced.
In practical terms, this remediation may involve soil cleanup, water decontamination, or the recovery of natural areas degraded by human activity or environmental disasters. SEMARNAT (Secretariat of Environment and Natural Resources) and PROFEPA (Federal Attorney for Environmental Protection) are the main authorities that supervise and guarantee the implementation of these processes in the country. The Agency for Safety, Energy and Environment (ASEA) also plays a crucial role in the remediation of contaminated sites in Mexico, especially in activities related to the hydrocarbon sector.
What to do if you have contaminated soil?
If you discover that you have a contaminated site in Mexico, it is crucial that you follow a set of specific steps to comply with environmental legislation and protect both the environment and public health. Below are the steps you should follow:
1. Identification and Characterization of the Contaminated Site
- Detection : Identify any signs of contamination on site, such as spills, strong odors, soil discoloration, or the presence of hazardous materials.
- Characterization : Hire a certified company to conduct site characterization studies. These studies should assess the type and level of contaminants, as well as the extent of contamination (soil, groundwater, etc.).
2. Notification to the Authorities
- Inform ASEA or SEMARNAT : Depending on the nature of the contamination, you must notify the Agency for Safety, Energy and Environment (ASEA) If it involves activities related to hydrocarbons, or to the Ministry of Environment and Natural Resources (SEMARNAT) if it is of another nature.
Those responsible for pollution must Immediately inform the environmental authorities (SEMARNAT, PROFEPA, ASEA) about any contamination incident, specifying the type and quantity of contaminant, and the measures taken to contain the damage.
- Preventive Report : If the contamination was accidental, it is necessary to submit a preventive report to the corresponding authority, detailing the incident and the immediate containment measures adopted.
3. Environmental Impact Assessment (EIA)
- Request an Environmental Impact Assessment : If the contamination is significant, you must process it with SEMARNAT, where the impacts will be analyzed and mitigation and remediation measures will be proposed. This is mandatory if the contamination seriously affects the environment.
4. Preparation and Presentation of a Remediation Plan
- Remediation Plan Design : Develop a remediation plan that includes the specific actions that will be taken to clean up the site. This plan must be developed by certified professionals and must consider the applicable Mexican Official Standards (e.g., NOM-138-SEMARNAT/SS-2003 and NOM-147-SEMARNAT/SSA1-2004).
- Approval by the Authority : Submit the remediation plan to SEMARNAT or ASEA for approval. You must wait for authorization before starting any remediation action.
5. Implementation of the Remediation Plan
- Implement Remedial Measures : Once the plan is approved, proceed to implement remedial measures as planned. This may include removal of contaminated soil, on-site or off-site treatment of contaminants, and other cleanup techniques.
- Continuous Monitoring : During and after remediation, continuous monitoring of the site is essential to ensure that measures are effective and that no environmental or health risks persist.
6. Supervision and Verification
- Supervision by the Authority : ASEA, SEMARNAT or PROFEPA (Federal Attorney General for Environmental Protection) will supervise compliance with the remediation plan and may carry out inspection visits.
- Final Report : Once remediation is complete, you must submit a final report to the authority, demonstrating that the site has been remediated in accordance with regulations and that contaminants have been removed or reduced to safe levels.
7. Management of Generated Waste
- Waste Disposal : Waste generated during remediation must be managed in accordance with the General Law for the Prevention and Comprehensive Management of Waste (LGPGIR) and the corresponding NOMs. This includes classification, transportation and final disposal at authorized sites.
8. Prevention of Future Incidents
- Procedure Review : Evaluate and improve your operating procedures to prevent future contamination. Implement environmental management systems, such as ISO 14001, to strengthen environmental control and monitoring of your activities.
- Training : Train your staff in good environmental practices and in the correct handling of hazardous materials to prevent future incidents.
9. Legal and Technical Consulting
- Specialized Consulting : Hire legal and technical consultants specialized in environmental law to ensure compliance with all legal regulations and procedures.
10. Communication with the Community
- Transparency and Communication : Maintain open communication with the local community affected by the contamination, informing them about the remediation measures you are taking and the results obtained.
Environmental Management for Soil Remediation in Mexico
Environmental management of these wastes seeks to minimize the adverse effects of pollution, comply with environmental laws, promote sustainable development, and control the costs of storage, transportation, and treatment. This management is of concern to both the industrial and academic sectors. Incorporating oily wastes into the soil is one treatment option, but if handled incorrectly it can cause environmental problems. Oil spills and improper waste storage increase these problems, which has led to the search for technically and economically effective alternatives.
Following these steps will not only help you comply with Mexican legislation, but will also contribute to the protection of the environment and public health, minimizing legal and financial risks for your organization.
Why is this information important?
In Mexico, there are strict laws requiring companies and individuals to manage and remediate contaminated sites. Complying with these laws avoids financial, legal, and criminal penalties that can result from uncontrolled pollution.
Properly managing a contaminated site and being proactive in remediation enhances a company or organization's reputation. It demonstrates a commitment to social responsibility and the well-being of local communities, which is increasingly valued by consumers, investors and other key stakeholders. Transparently and effectively managing a contaminated site contributes to maintaining positive relationships with nearby communities. This can be crucial for the continuity of operations and for avoiding social conflicts.
Do you have any questions?
- Learn about our experts' process for determining whether a land is contaminated and the remediation process
- Discover all the solutions that exist to address this problem and the regulations that are involved.
- Review real examples and budgets of this type of activities in a practical way