Monitoring Objectives - the first step

We monitor the environment to search for and document change.

What are the potential changes that matter most?

This is the first question we have to address in improving the efficiency of a monitoring program. Yet, it is often a question that goes unexamined in the years after installation of a remedy.

Every statistics text book covers experimental design and setting objectives for data collection to some extent - but the memory of these guidelines fades with the age of the project and becomes crushed into a monotonous routine over time.

Getting to the point, monitoring objectives for the network should be fresh. Objectives should be well articulated and connected to observable metrics, statistical analyses and specific monitoring locations. Most importantly, objectives should be reviewed regularly to see if they still fit the management decisions that must be made.

Based on USEPA documents, monitoring objectives for a plume fall into four general categories (USEPA, 1994; USEPA, 2004a).

· Evaluate changes in ambient physical conditions of the resource;

· Evaluate the movement and monitor the fate of chemical constituents;

· Evaluate compliance with regulatory requirements;

· Evaluate the effectiveness of the response action or remedy

I might add:

¨ Demonstration of compliance at property boundaries or institutional controls

Sure, one of your objectives is to “evaluate the efficacy of your remedy”, but have you really considered what kind of data will show your remedy is working? Chances are the remedy will not completely eliminate constituents of concern immediately, so you need to have metrics that reflect the gradual move toward cleanup goals. What do these metrics looks like?

Specific monitoring objectives should be developed to address each of the applicable general objectives. Specific objectives for long-term monitoring (LTM) programs generally have temporal and spatial components. The most common temporal aspect of LTM objectives is the evaluation of changes in contaminant concentrations at specific locations over time. Temporal objectives can be addressed by identifying trends in contaminant concentrations, or by estimating long-term summary statistics (mean, standard deviation) for concentration values (Zhou, 1996). An important aspect of establishing temporal objectives includes determining the sampling frequency for wells. Monitoring wells should be sampled at a frequency that captures changes in constituent concentrations without unnecessary or redundant sampling events. However, the frequency of reporting and management decisions are also critical. Will you have a statistically significant dataset to write your next report?

Objectives for monitoring constituents spatially are often related to predicting movement of constituents within the currently plume area or toward downgradient receptors. Spatial optimization is based on minimizing the uncertainty of predicting concentrations at critical locations within the monitoring network while eliminating redundant information. Spatial objectives are first addressed by identifying these critical monitoring locations. All wells are not created equal!

Each well should provide valuable (not redundant) information and all areas of interest should be represented by sampling locations. Areas that require no action or decisions can be removed from consideration before beginning the optimization. Frequently, response action documents will identify concentration ‘action levels’ at specific locations that may signal risk for downgradient receptors and trigger contingent response actions. The monitoring objective corresponding to this situation would be to predict, with confidence, any exceedences of the ‘action level’ at locations within the plume or locations that are surrogates for potential receptors.

In any case, establishing, reviewing and articulating monitoring goals is a critical first step in optimizing your monitoring program.

LTMO and Sustainability (part 1)

Sustainability is the new black.The concept of sustainability, as it applies to the environmental cleanup projects, centers on evaluating the impact of greenhouse gas generation or energy dependence of specific remediation processes. The tedious work of calculating the dependence of processes on fossil fuel input and other sustainability metrics will inevitably fall to Health, Safety and Environmental (HSE) departments and consultants. From my perspective, the practice of sustainability assessments is about where risk assessment was in the 1980's. As Herb Ward once told me in reference to risk assessment, it is a "dark art". The origins of the inputs, the construction of the formulae and meaning of results are not currently based on consensus science, as the science has yet to evolve. As with risk assessment during the 1980's, we are experiencing myriad approaches to calculating sustainability metrics with no single, reliable template for making these calculations. This is an exciting time, but can cause a lot of sleepless nights when you are assigned the task of assessing processes for 'sustainability' with no roadmap for conducting these audits. In the US, sustainability practice really crossed the Rubicon with the issuance of Executive Order 13423 Strengthening Federal Environmental, Energy, and Transportation Management in January 2007, when sustainability became an official policy with respect to federal agencies. (http://www.whitehouse.gov/news/releases/2007/01/20070124-2.html) Among other things, the executive order sets goals for federal agencies including improving energy efficiency, reducing greenhouse gas emissions, reducing water consumption (through life-cycle cost-effective measures), and instituting 'green' building standards. Notably, heads of agencies are tasked with the "collection, analysis, and reporting of information to measure performance in the implementation of this order". Where present, the stated goals (reduction of water consumption 2% annually) are not astounding. However, requiring a process for accounting for water and energy use and documenting 'sustainability' is a major step. Now, how does long-term monitoring optimization fit into the mandate for sustainability assessments? The process of groundwater monitoring may not, on the surface seem like a major environmental threat; however, once you consider the amount of effort that goes into mobilizing crews, sampling wells, disposal of purge water, laboratory analysis (with the associated chemical waste), and managing the data -- you can see where the impacts can be relatively large for the amount of information gained. Site managers that are able to reduce the frequency of groundwater sampling or reduce the total number of wells sampled while maintaining the same level of confidence in the size and concentrations within the plume can make major steps toward sustainability goals at legacy waste sites. Moving from quarterly sampling to annual sampling alone cuts sampling related impacts by three quarters. The key to accomplishing these reductions is the careful documentation of historic site data, articulating the goals of the monitoring program and identifying your future data needs. These will be topics of future postings.