Chapter 1

Questions

1. Give an example for each of the objectives of environmental sampling and analysis listed in the text.

   Students' answers may vary. Corresponding to each listed objective, examples are:

   1. Sampling and analysis of contaminant concentrations in wastewater effluent from an industrial source to comply with effluent standards (e.g., NPDES).
   2. Monitor atmospheric ozone to determine air quality change over time against the NAAQ standard.
   3. Collections of samples and analysis of contaminant concentrations in the air surrounding an oil spill site to ensure health standards are met.
   4. Collections of soil and groundwater samples for the analysis of pollutants in a former gasoline station where a bioremediation project is underway. The information on how much contaminant we currently have, and how quickly is the progress of this ongoing project is important for us to make decision and take action in environmental remediation.
2. Give examples of practice that will cause data to be scientifically defective or legally nondefensible.

   Some of these examples are: improperly trained sampler and analyst, lack of good laboratory practice, knowingly falsifying test results, using nonvalidated equipment, unsecured chain of custody, nontraceable standards for instruments, misconduct, conflict of interest (e.g., contract labs oftentimes work for the company that hired them), ineffective ethics programs, etc.

3. Define and give examples of systematic errors and random errors.

   Determinate errors (systemic errors) produce a known bias in the data. These errors can be traced and corrected. They are avoidable mistakes that are known to have occurred or were found later. Measurements that result from these types of errors can be discarded. Random errors are indeterminate errors. They cannot be identified or compensated for, and statistics must be applied to deal with the data.

4. Why are sampling and analysis integral parts of data quality? Between sampling and analysis, which one often generates more errors? Why?

   If a sample isn't collected properly, then all subsequent careful lab work is useless. On the other hand, if an analyst is unable to define data quality (precision, accuracy), then such data are also useless and the money and time spent in collecting these samples are wasted. Most people would think that data quality is supported by a state-of-the-art instrument in the lab analysis, rather than sampling stage. However, this is typically not true. On the opposite, most error comes from sampling rather than lab analysis. For example, a sophisticated analytical instrument cannot justify the variations of chemicals in a very heterogeneous matrix.

5. Describe how errors in environmental data acquisition can be minimized and quantified.

   Errors can be quantified and minimized through a quality assurance/quality control (QA/QC) program. QA is more of a management system ensuring QC is working properly, and QC is a system of technical activities to meet certain data specifications. The use of a QA/QC program and adequate protocols will reduce errors associated with sampling, sample preservation, sample transportation, sample preparation, and sample analysis.

6. Why can't standard errors be added, but variances can?

   We cannot just add the standard errors or standard deviations, but we can add the variances as long as the variables are assumed to be independent such as errors from the stages of sampling and analysis. This is because during the variance calculations, the differences between every individual value from the mean are squared to get the positive values.

7. How does environmental analysis differ from traditional analytical chemistry?

   Analytical chemists trained in traditional chemistry curriculum may not be immediately adapted to environmental analysis. Environmental analysis differs from traditional analytical chemistry in many ways, for example:

   • Traditional analytical chemists stay in the lab, whereas environmental analytical chemists deal with measurements both in situ and in the lab.
   • The analytical costs of environmental chemicals are typically high.
   • There are always a large number of samples that require instrument automation.
   • Sample matrices are often complex and unknown (water, air, soil, waste, and living organisms).
   • The concentrations are typically very low. They are measured at ppm, ppb, ppt, or even lower levels.
   • The markets and analytical protocols are driven by regulations. An environmental analyst needs a working knowledge of the regulations for the purposes of both regulatory compliance and regulatory enforcement.

8. Describe the difference between "classical" and "modern" analysis.

   Modern analysis typically uses more or less sophisticated instrumental methods that make it possible to detect small quantities of almost anything. Examples of modern methods are spectrometric, electrometric, and chromatographic methods. The differences between "classical" and "modern" analysis are very arbitrary and ever-changing as technology advances. However, it is generally accepted that any "wet chemistry based" methods are termed "classical," while anything employing relatively sophisticated instrumentation is considered "modern" methods. Classical methods use wet chemicals analysis, mostly volumetric and gravimetric methods.

9. Why should a QA/QC program be used in an environmental lab or environmental analysis consulting lab to ensure they meet guidelines?

   QA/QC programs are implemented not only to minimize errors from both sampling and analysis, but also to quantify the errors in the measurement. Knowing how much the error and the means to minimize the errors will ensure guidelines are met.

10. Why might an analyst in the lab need to communicate well with the field sampler?

    Students' answers may vary.

    Communication is always essential in a team project consisting of sampling and analysis. For example, the analyst needs to communicate to the field sampler for proper sample preservation and storage protocols if optimal results are to be achieved.

11. Environmental professionals having strong sampling and analysis skills must not be timid in applying them to other types of sampling and analysis. Give an example of a discipline (e.g., pharmaceuticals, food and beverages, petroleum, forensics) or a scenario (e.g., detection of COVID-19) that you might pursue or encounter in your career. Elaborate your analysis with supporting publications.

    Students' answers may vary. For example, as Hass indicated (Charles N. Haas, Coronavirus and Environmental Engineering Science, Environ Engr Sci, 37(4):233-234, 2020), in applying to the global COVID-19 pandemic, "environmental engineering and science researchers and practitioners must not be timid in applying them to effect restoration and improvement of the publics' health." While we already know about the fate, transport, and control of chemical and biological agents, we can apply them to deal with the spreading and control of COVID-19 virus. Specifically in applying sampling and analysis principles, as we will learn from this course, composite sampling was a strategy used to overcome the shortfall of testing kits available during the outbreak of COVID-19.

12. A chemist is arguing that sampling is not as important as analysis. His concern is whether there is a need for a sampling course in an environmental curriculum. His main rationale is that most employers and governmental agencies already have their training courses alongside very specific and detailed procedures. Another consultant, on the contrary, argues that sampling should be given more weight than analysis. His main rationale is that a company always sends samples to commercial laboratories for analyses, and you do not become an analytical chemist by taking one course. For each of these two arguments, specify whether you agree or disagree and clearly state your supporting argument as to why you agree or disagree.

    Answers to this question will vary, but the main theme of the discussions is to illustrate the importance of both sampling and analysis for the environmental professionals and the graduating students in the environmental curriculum.

    1. "Sampling is not as important as analysis," and "is there a need for a sampling course"? Sampling is just as important, or even more important than analysis, because that is where the error originates. In most cases, a second chance is not available to get the same original sample. The sampling procedure must be rigorous, ensuring that a perfect representative sample is collected and at no time is the sample or sample bottle contaminated by the collector. The need for a "sampling" component in the environmental curriculum is obvious. Most environmental programs emphasize the study of environmental issues rather than the scientific tools needed to investigate these issues (Clement, 1992, Analytical Chemistry, vol. 64, No. 22, 1076A-1081A). As Clement (1992) described, many students seldom realize the consequences of poor sampling, they just assume an analytical result generated by a million-dollar state-of-the-art instrument is a number "carved in stone." This is not the case in reality, many times, sampling determines the magnitude of errors in the entire data...