How do you select the best soil sampling methods for your monitoring objectives?

1 Define your monitoring objectives

Before you start sampling, you need to define your monitoring objectives clearly and explicitly. What is the purpose of your monitoring? What are the questions you want to answer? What are the expected outcomes and outputs of your monitoring? Your monitoring objectives will guide your sampling design, methods, and analysis, as well as your data interpretation and reporting. For example, if your objective is to assess the spatial distribution of a contaminant in a soil site, you will need a different sampling design and method than if your objective is to evaluate the temporal trends of a contaminant in a soil profile.

2 Choose your sampling design

Your sampling design is the plan that specifies how many samples, where, when, and how to collect them. Your sampling design should be based on your monitoring objectives, as well as on the characteristics of the soil site, the sampling method, and the statistical analysis. There are different types of sampling designs, such as random, systematic, stratified, or adaptive, each with its own advantages and disadvantages. For example, random sampling is more suitable for heterogeneous soils and unknown contaminant distribution, while systematic sampling is more suitable for homogeneous soils and regular contaminant distribution.

3 Select your sampling method

Your sampling method is the technique that you use to collect the soil samples. Your sampling method should be compatible with your sampling design, your monitoring objectives, and your analytical methods. There are different types of sampling methods, such as grab, composite, or core, each with its own benefits and limitations. For example, grab sampling is more simple and fast, but less representative and more prone to errors, while composite sampling is more complex and time-consuming, but more representative and less variable.

4 Prepare your sampling equipment

Your sampling equipment is the tools and materials that you use to collect, store, transport, and analyze the soil samples. Your sampling equipment should be appropriate for your sampling method, your soil type, and your contaminant of interest. There are different types of sampling equipment, such as augers, spoons, tubes, or bags, each with its own specifications and requirements. For example, augers are more suitable for hard or compacted soils, while spoons are more suitable for soft or loose soils.

5 Follow your sampling procedures

Your sampling procedures are the steps and instructions that you follow to collect, store, transport, and analyze the soil samples. Your sampling procedures should be consistent with your sampling design, method, and equipment, as well as with the quality assurance and quality control standards. There are different types of sampling procedures, such as standard operating procedures, field manuals, or protocols, each with its own details and guidelines. For example, standard operating procedures are more formal and rigorous, while field manuals are more flexible and practical.

6 Evaluate your sampling results

Your sampling results are the data and information that you obtain from the soil samples. Your sampling results should be relevant for your monitoring objectives, as well as reliable and accurate. There are different ways to evaluate your sampling results, such as statistical analysis, data visualization, or data interpretation, each with its own methods and tools. For example, statistical analysis can help you test hypotheses, estimate parameters, or compare groups, while data visualization can help you explore patterns, trends, or outliers.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?