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Confirmatory Investigation
Contaminated Area Management
Confirmatory Investigation: A Vital Step in Environmental Protection
The Confirmatory Investigation represents a crucial milestone in the Contaminated Area Management (CAM) process, marking the transition from an approach based on observations and historical data to a direct and quantitative analysis of the presence of contaminants. This stage is based on the results of the Preliminary Assessment and aims to confirm or refute, through concrete scientific evidence, the existence of contamination in the areas being assessed. The Confirmatory Investigation not only validates the hypotheses previously formulated, but also provides the first quantitative data on the nature and extent of the possible contamination. This information is vital for guiding decisions on the need for more in-depth investigations or immediate intervention actions, playing a fundamental role in protecting public health and the environment.
Definition and Objective:
The Confirmatory Investigation is defined as a systematic process of collecting and analyzing environmental samples to determine the presence or absence of contamination in a specific area. Its primary objective is to confirm, through physical and chemical evidence, whether the suspicions of contamination raised during the Preliminary Assessment are well-founded.
The specific objectives include:
- 1. verify the presence of contaminants in areas identified in the Preliminary Assessment;
- 2. provide initial quantitative data on the types and levels of contaminants present;
- 3. determine whether contamination levels exceed regulatory standards or pose potential risks;
- 4. assessing the need for a detailed investigation or immediate intervention;
- 5. refine the conceptual model of the site developed during the Preliminary Assessment;
- 6. provide an initial database for future comparisons and trend assessments.
This stage is crucial for effectively directing resources in subsequent phases of the CAG, avoiding unnecessary spending on uncontaminated areas and focusing efforts where contamination is confirmed.
Methodologies and strategies
The Confirmatory Investigation methodology is a structured process that combines environmental sampling techniques with rigorous laboratory analysis. This approach aims to obtain reliable and representative data on the presence and levels of contaminants in an area under assessment.
The strategy involves:
- 1) Development of the sampling plan: Based on the results of the Preliminary Assessment, a detailed plan is drawn up, specifying locations, depths and types of samples to be taken;
- 2) Sample collection: Sampling of soil, groundwater, surface water, sediments and/or soil vapors, depending on the characteristics of the site and the suspected contaminants;
- 3. laboratory analyses: The samples collected are subjected to chemical analyses in laboratories accredited by the General Coordination of Accreditation (Cgcre), INMETRO's accreditation body, using standardized and recognized methods;
- 4. interpretation of results: Analytical data is evaluated against relevant regulatory standards and environmental quality guidelines;
- 5. Spatial distribution assessment: The results are analyzed to understand the horizontal and vertical distribution of contaminants on the site;
- 6. refining the conceptual model: the site's conceptual model is updated based on the new data obtained.
This methodology faces challenges such as the proper selection of sampling points, ensuring the representativeness of samples, proper handling and preservation of samples, and interpretation of results in areas with complex geology or multiple types of contaminants. The strategy to overcome these challenges includes the use of advanced sampling techniques, rigorous quality control protocols, and the application of statistical and geostatistical methods in data analysis.
Importance in the GAC process:
The Confirmatory Investigation is a critical component in the Contaminated Area Management process, serving as a bridge between initial suspicions and concrete environmental management actions. Its importance is manifested in several aspects:
Scientific validation
It provides concrete evidence of the presence or absence of contamination, moving the process from the field of speculation to that of scientific certainty
Prioritizing actions
Allows the identification and prioritization of areas that require immediate attention or more detailed investigations
Resource efficiency
Optimizes resource allocation by focusing efforts on areas where contamination is confirmed
The Confirmatory Investigation not only validates or refutes the hypotheses formulated in the Preliminary Assessment, but also establishes the basis for all subsequent decisions in the CCM process. It provides the first quantitative data on the nature and extent of contamination, essential for assessing potential risks and planning future actions.
In addition, this phase is fundamental for refining the conceptual model of the site, incorporating real data on the presence and distribution of contaminants. This updated model serves as a crucial tool for planning more detailed investigations and developing effective remediation strategies.
Contaminated Area Management Solutions
The Management of Contaminated Areas is a multifaceted process that requires a systematic and meticulous approach. Each stage of this process is crucial, building on the information and results of the previous phases, as established at the federal level by CONAMA Resolution No. 420/2009, in the state of São Paulo by CETESB Board Decision No. 38/2017/C and other applicable legislation, thus ensuring a comprehensive understanding and an effective solution to the challenges of contamination.
Servmar offers a comprehensive portfolio of services in Contaminated Area Management, combining technical expertise, advanced technologies and a deep understanding of the Brazilian regulatory context.
Find out more about our solutions:
Tools, Techniques and Expected Results:
Confirmatory Investigation uses a range of specialized tools and techniques to collect and analyze environmental data accurately and reliably. These tools and techniques are essential for gaining an initial understanding of the nature and extent of contamination.
Key tools and techniques include:
- Drilling and soil sampling equipment (hand augers, mechanical probes);
- Groundwater sampling systems (monitoring wells, low-flow samplers);
- Detectors for volatile organic compounds (VOCs) in the field;
- Passive sampling methods for soil gases;
- Surface sampling techniques for sediments and surface water;
- Advanced laboratory analytical methods (chromatography, mass spectrometry);
- Geostatistical modeling and data visualization software.
The expected results of a Confirmatory Investigation are crucial for directing the next stages of the CCM process. The main product is a report that presents and interprets the data collected. This report typically includes:
- Detailed description of the sampling activities carried out;
- Analytical results compared with relevant regulatory standards;
- Maps and cross-sections showing the distribution of contaminants;
- Assessment of the risks associated with the contamination detected;
- Recommendations for further investigation or immediate action, if necessary.
In addition, the results of the Confirmatory Investigation provide a crucial initial database for future comparisons and assessments of trends in the environmental quality of the site.
Next Steps in the GAC Process
The results of the Confirmatory Investigation directly determine the next steps in the Contaminated Area Management process. The decision on how to proceed is based on a careful evaluation of the data collected and its interpretation in the context of regulatory standards and potential risks.
If the Confirmatory Investigation detects significant levels of contamination that exceed regulatory standards or pose potential risks, the next step is usually a Detailed Investigation. This step involves a more comprehensive and detailed characterization of the contamination.
In cases where contamination is confirmed, but at low or localized levels, immediate remediation actions or continuous monitoring may be recommended, depending on the nature of the contaminants and the associated risks.
In situations where no contamination is identified, the GAC process can be terminated and resumed if there is interest in decommissioning a licensed activity, reusing the area or if required by the environmental agency responsible.
The decision on the next steps must be based on a careful assessment of the risks identified, taking into account both environmental, regulatory and economic aspects, always prioritizing the protection of public health and the environment.
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Frequently Asked Questions:
At Servmar, we are committed to providing clear and accurate information to help our customers better understand our services and the importance of environmental sustainability.
This FAQ section has been created to answer the most common questions, providing quick access to answers that can help you make informed decisions. We value transparency and open communication, and we are always happy to answer any other questions you may have.
The Confirmatory Investigation mainly aims to confirm the presence or absence of contamination in suspected areas, providing initial data on the types and levels of contaminants. A Detailed Investigation, on the other hand, is a more comprehensive study that fully characterizes the nature, extent and behaviour of the contamination, including its three-dimensional distribution, seasonal variations and migration potential. The Confirmatory Investigation usually involves limited sampling, while the Detailed Investigation is more extensive and can include multiple sampling campaigns.
A Confirmatory Investigation usually takes between 5 and 9 weeks to complete, depending on the complexity of the site and the scale of the investigation. This period includes planning (1-2 weeks), fieldwork for sample collection (1-2 weeks), laboratory analysis (2-3 weeks) and preparation of the final report (1-2 weeks). Factors such as the need for special permits or adverse weather conditions can extend this period.
The selection of sampling sites is based on multiple factors, including: results of the Preliminary Assessment, conceptual model of the site, geological and hydrogeological characteristics, potential sources and pathways of contamination identified and accessibility. Generally, a targeted approach is used, focusing on areas of greatest suspicion, combined with some random sampling points for validation. Statistical and spatial analysis techniques can be employed to optimize the distribution of sampling points.
The contaminants analyzed depend on the history of the site and the suspicions raised in the Preliminary Assessment. They commonly include:
- Volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs);
- Petroleum hydrocarbons;
- Metals and semi-metals;
- Pesticides and herbicides;
- PCBs (polychlorinated biphelines).
- PFAS (Per- and polyfluoroalkylated substances).
The specific list is determined on the basis of historical use of the site, present or past industrial activities, and applicable local regulations.
Interpreting the results involves comparing the levels of contaminants detected with the applicable regulatory standards, which can vary depending on the intended use of the land (residential, commercial, industrial) and local and national regulations. This comparison considers not only absolute concentrations, but also factors such as the depth of contamination, migration potential, and risks to human health and the environment. The interpretation also takes into account analytical uncertainty and the natural variability of the geochemical background. In cases where levels exceed standards, a more detailed risk assessment may be required to determine the significance of the results and guide further action.
