An inventory of potential sources of contamination located within the source water assessment area is necessary for proper source water protection, management, and planning. With this information, a public water system can be aware of potential impacts to its water supply. Knowledge of potential contaminants may encourage communities to develop and manage a source water protection area. An understanding of what types of contamination issues may occur will also enable a public water system to plan for necessary improvements in treatment capabilities or allow time to remediate the source of contamination.
The most common type of contaminants in Wyoming will be associated with permitted sources of contamination. Permitted sources of contamination produce contaminants which are regulated by state or federal laws. Examples of regulated activities or facilities include wastewater treatment plants; confined animal feeding operations; underground injection wells; chemical or hazardous waste use, production, or storage sites; and landfills. While not all permitted contaminant sources will pose a threat to drinking water resources, they will be viewed as potential sources of contamination.
4.2 Available Data
State and federal regulatory agencies maintain databases containing information on the activities and facilities which are regulated under existing state and federal laws. A list of the state and federal agencies, contact information, and the information available from each is presented as Appendix C.
In some situations, it may be necessary to obtain more accurate locations for potential sources of contamination identified in the contaminant inventory. DEQ would then contract with other public agencies or private firms to locate potential sources of contamination using global positioning system equipment.
Appendix D. Appendix D also contains a table listing the types of contaminants often associated with each potential source of contamination.
4.3 Types of Contaminant Inventories
The thoroughness of the contaminant inventory will be based on proximity to the drinking water well or intake. A more thorough inventory will be conducted in the source water assessment area zones which are closest to the well or intake. The type of public water system and delineation method used will influence how comprehensive an inventory is needed. Available resources including time, funding, and personnel may also affect the type of inventory which will be completed. Public water systems may always elect to conduct more extensive inventories.
Comprehensive Inventory
A complete, or comprehensive, inventory will be conducted in Zones 1
and 2 for both surface water and groundwater sources. All readily
available information identified in Appendix C will be used to
develop a list of potential sources of contamination present in the
source water assessment area. These potential sources of
contamination will primarily consist of state and federal regulated
activities and major non-point source contamination sources. For
groundwater sources in confined aquifers, the contaminant inventory
will focus on possible sources of contamination which could breach the
confining layer(s) of the aquifer.
As part of the comprehensive inventory, the assistance of local representatives will be encouraged. The verification of regulated potential source of contamination locations and the identification of local or historical potential sources of contamination will supplement the results obtained in the state and federal database search. The combination of local and DEQ efforts will produce a complete and useful contaminant inventory.
Limited Inventory
A limited contaminant inventory will be conducted in Zone 3 for both
surface water and groundwater sources. A limited inventory will
include major state and federal regulated activities. These will
include, at a minimum, superfund sites, hazardous waste disposal
sites, and federal facilities. No local contaminant inventory efforts
will be necessary in Zone 3 areas. A public water system, however,
may always elect to do a comprehensive inventory in Zone 3.
Transient Noncommunity Systems
Giardia lamblia and nitrates. Confirmed releases to
groundwater or surface water within the assessment area contained in
DEQ's databases will also be identified.
This limited contaminant inventory is allowed by the EPA. The EPA State Source Water Assessment and Protection Program Guidance (Final Guidance, August 1997) specifies, `For transient noncommunity systems, a state may decide to conduct assessments that identify sources of microbial and nitrate contamination only within a specified distance from the drinking water well, leaving more detailed assessment efforts for all community water systems and the majority of nontransient noncommunity water systems' (p. 2-10).
4.4 Contaminants of Concern
The contaminants of concern include those contaminants regulated under the Safe Drinking Water Act plus additional microorganisms such as Cryptosporidium. Microorganisms not currently regulated under the Safe Drinking Water Act are included as contaminants of concern for Wyoming's Source Water Assessment Program in anticipation of upcoming federal rules. Cryptosporidium is included in the proposed Enhanced Surface Water Treatment Rule and pathogenic viruses and bacteria will be addressed under the proposed Groundwater Disinfection Rule. Contaminants of concern are listed in a table included in Appendix D. Contaminants are grouped by volatile or soluble organic carbons, inorganic compounds, and microorganisms. Radionuclides are also listed. Each contaminant listed in Appendix D has a Chemical Abstracts Service (CAS) registry number which can be used to search for details about that contaminant for planning or emergency response purposes
Chapters
1 |
2 |
3 |
4 |
5 |
6 |
7
Glossary |
Acronyms
Appendices
A |
B |
C |
D
Wyoming's Source
Water Assessment Guidance Document Contents