APPENDIX E - Elements for Drafting the Characterization Plan
Selection of sampling stations
The reference stations must be selected so as to reveal any other source of potential disruption that could influence the characteristics of the variables measured at the surveillance or monitoring stations. Optimal study design also includes a temporal reference, i.e., data on the study site before the beginning of activities (reference state). Unfortunately, it is not always possible to generate this data before commencement of the dredging or sediment management activities.
It is generally easy to locate the reference stations for the components or the physical or chemical parameters. For example, to measure the changes in surface water or groundwater quality, one or two stations can be chosen upstream and downstream from the work area, in relation to the streamflow direction. To assess air quality, two to four stations can be chosen, located on the periphery outside the area of influence, if possible.
However, the selection of the reference stations for the biological components is more complex. Thus, to measure the impacts of the disposal of dredged materials on the biological communities, the reference stations must be chosen according the following factors (Germano et al., 1994):
- the reference stations must have the same biological community structure as the disposal site, as measured in the ecosystem reference state studies;
- the sediments must exhibit the same physicochemical characteristics as those of the disposal sites;
- the reference stations and the disposal site stations must be located at comparable depths and as close as possible to each other, while ensuring that the reference stations are located outside the area of influence. However, the reference stations must be set back from the movements of water masses at the disposal site.
The number of reference stations required is determined according to their representativeness and the scope of the sampling plan. In the case of disposal in open water, several reference sites may be necessary when the bathymetry and the geochemistry of the sediments at the disposal site proper as well as outside the disposal site are different.
For the surveillance of suspended particulate matter (SPM) at a dredging site, the water quality sampling stations should be located near sensitive areas and distributed among several sites in the SPM dispersion plume. At disposal sites in aquatic environments, water quality surveillance stations must be sampled before commencing the work to determine the natural variability of the parameters studied, particularly during meteorological and hydrodynamic conditions that significantly disrupt the environment. Periods of heavy ship traffic must also be considered as a disruptive factor. These aspects can also be verified for the reference areas.
However, the sampling plan remains scalable in the context of a follow-up program.
Determination of the number of samples
The number of samples to be collected at each station depends on the spatial and temporal heterogeneity of the variable being measured. A minimum number of samples must be established according to static parameters useful to the analysis. The process of defining data quality objectives is very useful for this determination.
Establishment of the sampling frequency
The sampling frequency depends on several factors, particularly the uncertainty regarding the technology used for dredging or sediment management or the stability of the disposal site.
Selection of the field and laboratory analytic methods
The purpose of this activity is to select the analytic method associated with the “measurement parameter/relational tool” combination previously selected. Due to the many factors to be considered in the selection of analyses and interpretation of raw data, it is difficult to establish a list of selection criteria in advance. Professional judgment therefore plays an important role in this choice. However, the selected criteria must at least allow establishment of the relevance of the data according to the measurement parameter sought and an assessment of the quality of the information according to the quality objectives defined in the quality assurance and quality control program.
The sampling planning process must include selection of the analytic methods (including determination of the detection thresholds), the sample volumes to be collected and the sample conservation methods. The Sediment Sampling Guide for Dredging and Marine Engineering Projects on the St. Lawrence River (Environment Canada, 2002a; 2002b) and the Guide de caractérisation physico-chimique et toxicologique des sédiments (CEAEQ, in prep.) provide useful information relative to this activity.
Screening tools (analyses, tests, etc.) can also assist in the effective and economical acquisition of numerous data, either by quickly delimiting the problem area to be assessed (e.g., to determine the extent of contamination) or by assessing the effectiveness of remediation (e.g., to determine the sediment layer to be dredged). When the sector to be assessed has been delimited by means of screening tools, a sampling strategy can then confirm the screening results (CCME, 1993a; 1993b) and allow more precise characterization.
For definitive analyses (as opposed to screening analyses), the number of samples to be analyzed must be carefully determined based on the available budget and considering that the logistics of sample conservation, transportation and pretreatment require more handling and consequently are more costly.
Identification of shipping procedures and sample conservation modes
Depending on the different analyses that must be performed on the collected samples, it is important to select the appropriate sample conservation mode in order to preserve sample integrity. It is also important that the procedures for shipping samples to the different laboratories be adequate, which includes sample identification and packaging. It is therefore essential that there be good communication between the sampling teams and the laboratory teams, starting from the planning phase of the work. The Sediment Sampling Guide for Dredging and Marine Engineering Projects on the St. Lawrence River (Environment Canada, 2002a; 2002b), the Guide de caractérisation physico-chimique et toxicologique des sédiments (CEAEQ, in prep.), and the documents of the Canadian Council of Ministers of the Environment (CCME, 1993a; 1993b) provide useful information relative to this activity.
Selection of sampling equipment and procedures
The sampling equipment and procedures must be selected taking account of the prevailing field conditions at the sampling stations as well as the sample characteristics and type, number and frequency, and analytic methods, etc. The Sediment Sampling Guide for Dredging and Marine Engineering Projects on the St. Lawrence River (Environment Canada, 2002a; 2002b) and the Guide d’analyse physico-chimique et toxicologique des sédiments (CEAEQ, in prep.) provide useful information relative to this activity.
Establishment of the occupational health and safety program
The occupational health and safety programs must specify the personal protective equipment required (eyewear, boots, etc.) and the devices for surveillance of worker exposure to certain chemicals. The document entitled The Inspector’s Safety Guide: A Field Guide for Environment Canada Inspectors (1996) presents good examples of safety measures for personnel responsible for collecting samples.
Bibliography
CCME (1993a). Guidance Manual on Sampling, Analysis and Data Management for Contaminated Sites. Volume I: Main Report. CCME Report EPC-NCS62E. December 1993.
CCME (1993b). Guidance Manual on Sampling, Analysis and Data Management for Contaminated Sites. Volume II: Analytical Method Summaries. CCME Report EPC-NCS66E. December 1993.
Environment Canada (2002a). Sediment Sampling Guide for Dredging and Marine Engineering Projects on the St. Lawrence River. Volume 1, Planning Guidelines. Environmental Protection Branch, Environment Canada. 104 pp. (Volume - Navigation – Phase III).
Environment Canada (2002b). Sediment Sampling Guide for Dredging and Marine Engineering Projects on the St. Lawrence River. Volume 2, Field Operations Manual. Environmental Protection Branch, Environment Canada. 104 pp. (Volume - Navigation – Phase III).
Environment Canada (1996). The Inspector’s Safety Guide: A Field Guide for Environment Canada Inspectors. Enforcement Bureau, Environmental Protection Service, Environment Canada.
Germano, J.D., Rhoads, D.C. and Lunz, J.D. (1994). An Integrated, Tiered Approach to Monitoring and Management of Dredged Material Disposal Sites in the New England Region. Rapport préparé par Science Applications International Corporation (SAIC) for U.S. Army Corps of Engineers, New England Division, Disposal Area Monitoring Systems (DAMOS) Contribution 87.
MDDELCC – Ministère du Développement durable, de l’Environnement, de la Faune et des Parcs du Québec et Environment Canada. in preparation. Guide to physicochemical and toxicological characterization of sediments. St. Lawrence Action Plan: Environment Canada, Ministère du Développement durable, de l’Environnement, de la Faune et des Parcs du Québec. Provisional title, in preparation.