Before a water-quality investigation can be conducted, information about the sampling locations, sampling parameters and methods that will be used is needed. This information is required for writing federal or state sampling plans (see STEP 3). In addition, any sampling cannot proceed until a plan has been developed that specifies the locations, number of samples, kinds of samples, numbers and kinds of QA/QC samples, and desired quality of the data. The samplers are responsible for collecting and handling samples and keeping records in strict accord with the sampling plan.

Safeguarding Your Health and Safety

Before attempting any water quality sampling you must be aware of the applicable health and safety requirements. Because sample collection often is done at contaminated sites or in remote, rugged country far from immediate medical attention, it is important to follow all health and safety requirements and guidelines (see STEP 9).

Sampling stations are selected during development of the sampling plan (see STEP 3). When selecting stations, consider the sampling objectives, the laboratory analyses, the statistical analyses, as well as data archiving requirements. When several individuals or departments are responsible for these different aspects of the sampling project, use a team or consultation approach to sample plan development. If the investigator has primary responsibility for station selection, he or she should consult with the appropriate individuals and review all available information in order to answer the following questions (QAPP, 1991):

( ) Can samples be obtained throughout the entire year (i.e. seasonal well) and at all discharges?

( ) Where should samples be collected to measure a site's regional or local water quality?

( ) Have all existing sampling locations been identified?

( ) Which of the existing locations should, if possible, be incorporated in the sampling program?

( ) How efficient is the sampling array (over sampling as well as under sampling should be avoided)?

( ) Is the sample size adequate for obtaining statistically valid results?

Determining the representative physical, chemical and biological conditions of surface water and ground water requires first gathering available information about the locations of existing sampling stations in streams, rivers, lakes, monitoring wells and supply wells. The most important sources of information are:

( ) Data bases maintained by federal, state and local agencies

( ) U.S. Geological Survey (USGS) and Instituto Nacional de EstadÈstica GeografÈa e Informötica (INEGI) topographic quadrangles

( ) Land-use information, including aerial photographs

( ) Published and unpublished reports, studies and data

( ) Geologic maps and water-table contour maps

Examining these data may reveal that new stations must be established to achieve sampling objectives. A station is a specific location next to or on a water body, or at a well or group of wells from which a sample is collected. Its location is critical to the success of the sampling program. To be effective, sampling stations must be optimally located in the hydrologic flow system to assess water quality and detect contamination from point or nonpoint sources. For example, a river station should be located at or near a stream flow gauging station so that both stream discharge and water-quality data can be collected simultaneously. Additional monitoring wells around sites of contamination may be needed to determine the full extent of degradation from poor disposal practices. If no such sampling locations are available, then new stations should be established using the best information available. Areas where new stations are established will be identified while developing the sampling plan.

B. Permission to Inspect, Construct and Survey

After the number, type and locations of stations have been estimated, legal access must be obtained from all owners or operators of the property to conduct a site reconnaissance. A written or oral request for entry should include a description of proposed inspection, construction and sampling activities.

In many cases, federal, state and county officials and designated contractors have statutory authority to conduct field investigations at suspected or known pollution sources, such as RCRA and CERCLA sites in the United States. For such officials, legal access ranges from verbal consent to administrative search warrants. Non-governmental researchers must obtain written consent from property owners or operators. If possible, offer the owner a copy of the sampling and analysis results. Regardless of affiliation, be certain to notify the local environmental or health agency in advance of field studies. When establishing a new station, inform the owners or operators that at least three visits may be required before the actual sampling takes place (STEP C below).

Regardless of the purpose of the visit, adhere to all prescribed health and safety procedures when entering or working on a site.

C. Establishing a Sampling Station

If new stations are being added, describe their number, type, location and construction before continuing the sampling process. At least three visits may be required to establish new stations before sampling takes place to do the following:

1. Select and examine the potential station through reconnaissance to ensure that the surface water body or well is at the optimum location to provide water quality data. At a river, for example, find a section where the channel is smoothest, straightest, accessible and uniform in depth, at least 100 meters (330 feet) upstream from a confluence, and near a landmark, such as a bridge, large boulder or tree. If the river is flowing, measure its temperature, pH, electrical conductivity, or dissolved oxygen at regular intervals and depths across the channel to test the degree of mixing of flowing water. The variability in these parameters will help you decide whether or not the site can be used. A well-mixed channel requires fewer samples to be composited than one showing distinct changes from one location to another. Other major siting considerations are the locations of upstream or downstream sources of contamination and their impact on water quality, and whether or not you can access the station at all discharges.
2. To establish a ground water station, check existing monitoring or supply wells for ease of access and overall condition. Lower a tape or other measuring device to the bottom of the well to determine its total accessible depth. Check records for details of well construction, lithology, depth to water, aquifer test results, location and length of well screen, and original depth of the well;
3. Install a monitoring well according to federal or state guidelines and test it for hydrogeologic properties (e.g., aquifer tests). Collect and describe soil and water samples during well construction; and
4. Survey the location of the measuring point for each station (e.g., bridge, culvert, gauge, top of casing) to the nearest 3 mm (0.01 foot) vertically and within 25 meters (80 feet) horizontally (EPA, 1991), and locate on a map with a schematic and photographs.

If the stations you will be sampling are located across the U.S.- Mexico Border, there are additional actions you must take. Before a water quality investigation of any kind can be conducted, permission must be obtained from the Mexican government through the ComisiZn Internacional de LÈmites y Aguas (CILA).

Both EPA and ADEQ require the preparation of sampling plans before water-quality samples are collected. The EPA reference is "Preparation of a USEPA Region 9 Sample Plan for EPA-Lead Superfund Projects," dated August 1993 (available from the Region 9 Quality Assurance Management Section). The ADEQ reference is "Quality Assurance Project Plan," May 1991 (available from the ADEQ Office of Water Quality in Phoenix). Sample plans for projects under EPA jurisdiction must contain a Cover Sheet (EPA Format) and the following Sample Plan Components:

VII. Health and Safety Plan

For projects under the jurisdiction of the State of Arizona, there are four types of sample plans available, depending on the type and scope of the project:

1. ADEQ Sample Plan;
2. Abridged Groundwater Sample Plan;
3. Ambient Surface Water Sample Plan; and
4. Generic Sample Plan for Surface Water Quality Investigations.

The required sections are similar to those in EPA's sample plan, but are arranged in a different order and use ADEQ forms.

EPA sample plans are required by EPA Region 9 for all federal-lead Superfund and RCRA projects. Use ADEQ sample plans for all other sites in Arizona. Contact ADEQ for more information.

Official guidelines are intended to ensure that a complete and consistent sampling plan has been developed before any sampling takes place. A complete sampling plan protects the sampling agency from errors and omissions that could compromise or invalidate sampling results. Water quality sampling is expensive and time-consuming, so be certain before you start that samples will serve project goals.

After preparing the sampling plan, send it to the responsible agency for approval. Even if your sampling program does not require an officially sanctioned sampling plan, preparing a plan that follows federal or state agency guidelines is a good practice. A good sampling plan actually saves time because it can be used for many sampling events and may be applicable to a variety of projects. Keep in mind the objectives of your sampling so that time and money is not wasted by acquiring data that are either too precise or not precise enough for your objectives.

------- End of Phase I -------