TITLE 9. ENVIRONMENT
REGISTRAR'S NOTICE: The State Water Control Board is claiming an exemption from the Administrative Process Act in accordance with § 2.2-4006 A 3, which excludes regulations that consist only of changes in style or form or corrections of technical errors. The State Water Control Board will receive, consider, and respond to petitions by any interested person at any time with respect to reconsideration or revision.
Titles of Regulations: 9VAC25-20. Fees for Permits and Certificates (amending 9VAC25-20-70).
9VAC25-101. Tank Vessel Oil Discharge Contingency Plan and Financial Responsibility Regulation (amending 9VAC25-101-40, 9VAC25-101-50).
9VAC25-260. Water Quality Standards (amending 9VAC25-260-155).
9VAC25-590. Petroleum Underground Storage Tank Financial Responsibility Requirements (amending 9VAC25-590-220).
9VAC25-650. Closure Plans and Demonstration of Financial Capability (amending 9VAC25-650-110, 9VAC25-650-200).
Statutory Authority:
9VAC25-20: §§ 62.1-44.15 and 62.1-44.15:6 of the Code of Virginia.
9VAC25-101: §§ 62.1-44.15, 62.1-44.34:16, and 62.1-44.34:21 of the Code of Virginia.
9VAC25-260: § 62.1-44.15 of the Code of Virginia.
9VAC25-590: § 62.1-44.34:9 and § 62.1-44.34:12 of the Code of Virginia.
9VAC25-650: §§ 62.1-44.15 and 62.1-44.18:3 of the Code of Virginia.
Effective Date: June 6, 2012.
Agency Contact: Debra A. Miller, Department of Environmental Quality, 629 East Main Street, P.O. Box 1105, Richmond, VA 23218, telephone (804) 698-4206, FAX (804) 698-4346, TTY (804) 698-4021, or email debra.miller@deq.virginia.gov.
Summary:
The regulatory action updates the mailing address for the Department of Environmental Quality.
9VAC25-20-70. Method of payment.
A. Fees shall be paid by check, draft or postal money order payable to the Treasurer of Virginia, or submitted electronically (if available), and must be in U.S. currency, except that agencies and institutions of the Commonwealth of Virginia may submit Interagency Transfers for the amount of the fee. All fees shall be sent to the following address (or submitted electronically, if available): Department of Environmental Quality, Receipts Control, P.O. Box 10150 1105, Richmond, Virginia 23240 23218.
B. Required information. All applicants for new permit issuance, permit reissuance or permit modification shall submit the following information along with the fee payment:
1. Applicant name, address and daytime phone number.
2. Applicant Federal Identification Number (FIN).
3. The name of the facility/activity, and the facility/activity location.
4. The type of permit applied for.
5. Whether the application is for a new permit issuance, permit reissuance or permit modification.
6. The amount of fee submitted.
7. The existing permit number, if applicable.
9VAC25-101-40. Board oil discharge contingency plan review and approval.
A. Tank vessel oil discharge contingency plans shall provide for the use of the best available technology (economically feasible, proven effective and reliable and compatible with the safe operation of the vessel) at the time the plan is submitted for approval, be written in English, and, in order to be approvable, shall contain, at a minimum, the following information:
1. The vessel name, country of registry, identification number, date of build and certificated route of the vessel.
2. The names of the vessel operators including address and phone number.
3. If applicable, name of local agent, address and phone number.
4. A copy of the material safety data sheet (MSDS) or its equivalent for each oil, or groups of oil with similar characteristics, transported or transferred by the tank vessel. To be equivalent, the submission must contain the following:
a. Generic or chemical name of the oil;
b. Hazards involved in handling the oil; and
c. A list of firefighting procedures and extinguishing agents effective with fires involving each oil or groups of oil demonstrating similar hazardous properties which require the same firefighting procedures.
5. A complete listing, including 24-hour phone numbers, of all federal, state and local agencies required to be notified in event of a discharge.
6. The position title of the individual(s) responsible for making the required notifications and a copy of the notification check-off list. The individual(s) must be fluent in English.
7. The position title, address and phone number of the individual(s) authorized to act on behalf of the operator to implement containment and cleanup actions. The individual(s) must be fluent in English and shall be available on a 24-hour basis to ensure the appropriate containment and cleanup actions are initiated.
8. The position title of the individual(s) designated by the operator to ensure compliance during containment and cleanup of a discharge, with applicable federal, state and local requirements for disposal of both solid and liquid wastes.
9. A copy of the valid evidence of financial responsibility pursuant to 9VAC25-101-45.
10. A complete description of the vessel including vessel drawings providing a complete view of the location of all cargo tanks as well as the location of fuels and other oils carried in bulk by the vessel.
11. A complete description of each oil transfer system on the vessel, including:
a. A line diagram of the vessel's oil transfer piping, including the location of each valve, pump, control device, vent, safety device and overflow;
b. The location of the shutoff valve or other isolation device that separates any bilge or ballast system from the oil transfer system; and,
c. The maximum pressure for each oil transfer system.
12. Identification and ensurance1 by contract, or other means acceptable to the board, of the availability of private personnel and equipment necessary to remove to the maximum extent practicable the worst case discharge and to mitigate or prevent a substantial threat of such a discharge. This contract or agreement shall ensure a certain response within the shortest feasible time. The department will accept a letter of understanding between the operator and response contractors which attests to this capability being readily available. Membership in a cleanup cooperative or other response organization is also acceptable. A listing of contractor or cooperative capabilities, including an inventory of the equipment and specification of the other information required by subdivision 14 of this subsection shall be included unless these capabilities are already on file with the department.
13. Assessment of the worst case discharge, including measures to limit the outflow of oil, response strategy and operational plan. For the purpose of this chapter, the worst case discharge for a tank vessel is a discharge in adverse weather conditions of its entire cargo.
14. Inventory of onboard containment equipment, including specification of quantity, type, location, time limits for gaining access to the equipment, and, if applicable, identification of tank vessel personnel trained in its use.
15. If applicable, a copy of the United States Coast Guard approved oil transfer procedures and International Oil Pollution Prevention Certificate (IOPP).
16. A description of training, equipment testing, and periodic unannounced oil discharge drills conducted by the operator to mitigate or prevent the discharge, or the substantial threat of a discharge.
17. The tank vessel's cargo inventory control procedures. Tank vessel operators shall ensure that this control procedure is capable of providing for the detection of a discharge of oil within the shortest feasible time in accordance with recognized engineering practices and industry measurement standards.
18. A post discharge review procedure to assess the discharge response in its entirety.
B. All nonexempt tank vessel operators shall file with the department the Application for Approval of a Tank Vessel Contingency Plan form available from the department for approval of the contingency plan. This form identifies the tank vessel operator by name and address and provides information on the tank vessel or vessels and shall be submitted with the required contingency plan and shall be completed as far as it pertains to the tank vessel. The operator must sign and date the certification statement on the application form which certifies to the board that the information is true and accurate. If the operator is a corporation, the application form must be signed by an authorized corporate official; if the operator is a municipality, state, federal or other public agency, the application form must be signed by an authorized executive officer or ranking elected official; if the operator is a partnership or sole proprietorship, the application form must be signed by a general partner or the sole proprietor.
C. Contingency plans must be filed with and approved by the board. A signed original shall be submitted to the department at the address specified in subsection F of this section. A copy of the original with the tank vessel specific information and the approval letter shall be retained on the tank vessel and shall be readily available for inspection. An operator of a tank vessel whose normal operating route does not include entry into state waters shall certify to the board, within 24 hours of entering state waters, that the operator has ensured by contract or other means acceptable to the board, the availability of personnel and equipment necessary to remove to the maximum extent practicable the worst case discharge and to mitigate or prevent the discharge or the substantial threat of a discharge. The operator shall submit a contingency plan to the board for approval in accordance with this chapter prior to the next entry of the tank vessel into state waters.
D. An operator of multiple tank vessels may submit a single fleet contingency plan. The plan shall contain vessel specific information required by this section for each vessel. The vessel specific information shall be included in appendices to the plan. This plan shall be separate from any required facility contingency plan.
E. Oil discharge contingency plans shall be reviewed, updated if necessary, and resubmitted to the board for approval every 60 months unless significant changes occur sooner. Operators must notify the department of significant changes and make appropriate amendments to the contingency plan within 30 days of the occurrence. For the purpose of this chapter, a significant change includes the following:
1. A change of operator of the tank vessel or individual authorized to act on behalf of the operator;
2. A substantial increase in the maximum storage or handling capacity of the tank vessel;
3. A material decrease in the availability of private personnel or equipment necessary to remove to the maximum extent practicable the worst case discharge and to mitigate or prevent a substantial threat of such a discharge;
4. A change in the type of product transported or transferred in or by any tank vessel covered by the plan for which a MSDS or its equivalent has not been submitted; or
5. The addition of a tank vessel to a single fleet contingency plan provided this requirement can be met by submittal of a new or amended appendix to the plan.
Renewals for expiring plans shall be submitted to the board for review and approval not less than 90 days prior to expiration of the current plan.
F. All applications and written communications concerning changes, submissions and updates of plans required by this chapter, with the exception of applications and submissions accompanied by fees addressed in subsection J of this section, shall be addressed as follows:
Mailing Address:
Virginia Department of Environmental Quality
Office of Spill Response and Remediation
P.O. Box 10009 1105
Richmond, VA 23240 23218
Location Address:
Virginia Department of Environmental Quality
Office of Spill Response and Remediation
629 East Main Street
Richmond, VA 23219
All applications and submissions accompanied by fees as addressed in subsection J of this section shall be sent to the addressed listed in subdivision J 2.
G. An oil discharge exercise may be required by the board to demonstrate the tank vessel's ability to implement the contingency plan. The department will consult with the operator of the vessel prior to initiating an exercise. Where appropriate, the department will ensure coordination with federal agencies prior to initiation of an exercise.
H. The board may, after notice and opportunity for a conference pursuant to § 2.2-4019 of the Code of Virginia, deny or modify its approval of an oil discharge contingency plan if it determines that:
1. The plan as submitted fails to provide sufficient information for the department to process, review and evaluate the plan or fails to ensure the applicant can take such steps as are necessary to protect environmentally sensitive areas, to respond to the threat of a discharge, and to contain and cleanup an oil discharge within the shortest feasible time;
2. A significant change has occurred in the operation of the tank vessel covered by the plan;
3. The tank vessel's discharge experience or its inability to implement its plan in an oil spill discharge exercise demonstrates a necessity for modification; or
4. There has been a significant change in the best available technology since the plan was approved.
I. The board, after notice and opportunity for hearing, may revoke its approval of an oil discharge contingency plan if it determines that:
1. Approval was obtained by fraud or misrepresentation;
2. The plan cannot be implemented as approved;
3. A term or condition of approval or of this chapter has been violated; or
4. The tank vessel is no longer in operation.
J. An application for approval of an oil discharge contingency plan will be accepted only when the fee established by this section has been paid.
1. Fees shall be paid by operators of tank vessels subject to this chapter upon initial submittal of an oil discharge contingency plan to the board. Renewals, additions, deletions or changes to the plan are not subject to the administrative fee.
2. Fees shall be paid in United States currency by check, draft or postal money order made payable to the Treasurer of Virginia. All applications and submissions accompanying fees shall be sent to:
Mailing Address:
Virginia Department of Environmental Quality
Office of Financial Management
P.O. Box 10150 1105
Richmond, VA 23240 23218
Location Address:
Virginia Department of Environmental Quality
Office of Financial Management
629 East Main Street
Richmond, VA 23219
3. Application fees for approval of tank vessel contingency plans are as follows:
a. For a tank vessel with a maximum storage, handling or transporting capacity of 15,000 gallons and up to and including 250,000 gallons of oil the fee is $718;
b. For a tank vessel with a maximum storage, handling or transporting capacity greater than 250,000 gallons and up to and including 1,000,000 gallons of oil the fee is $2,155; and
c. For a tank vessel with a maximum storage, handling or transporting capacity greater than 1,000,000 gallons of oil the fee is $3,353.
4. The fee for approval of contingency plans encompassing more than one tank vessel, as authorized by subsection D of this section, shall be based on the aggregate capacity of the tank vessels.
5. Application fees are refundable upon receipt of a written request for withdrawal of the plan and fee refund no later than 30 days after submittal and prior to approval of the plan.
6. Overpayments of application fees are refundable upon written request. Overpayments not refunded will be credited for the applicant's future use under this section.
9VAC25-101-50. Board financial responsibility demonstration.
A. The operator of any tank vessel entering upon state waters shall deposit with the board cash or its equivalent in the amount of $500 per gross ton of such vessel. If the operator owns or operates more than one tank vessel, evidence of financial responsibility need be established only to meet the maximum liability applicable to the vessel having the greatest maximum liability.
1. All documents submitted shall be in English and all monetary terms shall be in United States currency.
2. A copy of the board's acceptance of the required evidence of financial responsibility shall be kept on the tank vessel and readily available for inspection.
B. If the board determines that oil has been discharged in violation of applicable state law or there is a substantial threat of such discharge from a vessel for which a cash deposit has been made, any amount held in escrow may be used to pay any fines, penalties or damages imposed under such law.
C. Operators of tank vessels may obtain exemption from the cash deposit requirement if evidence of financial responsibility is provided in an amount equal to the cash deposit required for such tank vessel pursuant to § 62.1-44.34:16 of the Code of Virginia and subsection A of this section. The following means of providing such evidence, or any combination thereof, will be acceptable:
1. Self-insurance. Any operator demonstrating financial responsibility by self-insurance shall provide evidence of such self-insurance in a manner that is satisfactory to the board. An operator demonstrating self-insurance shall:
a. Maintain, in the United States, working capital and net worth each in the amount required by § 62.1-44.34:16 of the Code of Virginia and subsection A of this section.
(1) Maintenance of the required working capital and net worth shall be demonstrated by submitting with the application form an annual, current nonconsolidated balance sheet and an annual, current nonconsolidated statement of income and surplus certified by an independent certified public accountant. Those financial statements shall be for the operator's last fiscal year preceding the date of application and shall be accompanied by an additional statement from the operator's treasurer (or equivalent official) certifying to both the amount of current assets and the amount of total assets included in the accompanying balance sheet which are located in the United States and are acceptable for purposes of this chapter.
(2) If the balance sheet and statement of income and surplus cannot be submitted in nonconsolidated form, consolidated statements may be submitted if accompanied by an additional statement by the involved certified public accountant certifying to the amount by which the operator's assets, located in the United States and acceptable under this subsection C, exceed total liabilities and that current assets, located in the United States and acceptable under this subsection C, exceed its current liabilities.
(3) When the operator's demonstrated net worth is not at least 10 times the required amount, an affidavit shall be filed by the operator's treasurer (or equivalent official) covering the first six months of the operator's fiscal year. Such affidavits shall state that neither the working capital nor the net worth have fallen below the required amounts during the first six months.
(4) Additional financial information shall be submitted upon request by the department; or
b. Provide evidence in the form of a marine insurance broker's certificate of insurance, certificate of entry, or other proof satisfactory to the board that the operator has obtained oil pollution liability coverage through an operator's membership in a Protection & Indemnity (P&I) Club that is a member of the international group of P&I clubs or through coverage provided by a pool of marine underwriters in an amount sufficient to meet the requirements of § 62.1-44.34:16 of the Code of Virginia and subsection A of this section.
2. Insurance. Any operator demonstrating evidence of financial responsibility by insurance shall provide evidence of insurance issued by an insurer licensed, approved, or otherwise authorized to do business in the Commonwealth of Virginia. The amount of insurance shall be sufficient to cover the amount required by § 62.1-44.34:16 of the Code of Virginia and subsection A of this section. The operator shall provide evidence of such coverage in the form of a marine insurance broker's certificate of insurance or by utilizing a form worded identically to the Insurance Form Furnished as Evidence of Financial Responsibility in Respect of Liability for Discharge of Oil available from the department. The insurer must also comply with all requirements in the form available from the department.
3. Surety. Any operator demonstrating financial responsibility through a surety bond shall file a surety bond utilizing a form worded identically to the surety form available from the department. The surety company issuing the bond must be licensed to operate as a surety in the Commonwealth of Virginia and must possess an underwriting limitation at least equal to the amount required by § 62.1-44.34:16 of the Code of Virginia and subsection A of this section. The surety must also comply with all requirements in the Surety Bond Form Furnished as Evidence of Financial Responsibility in Respect of Liability for Discharge of Oil available from the department.
4. Guaranty. An operator demonstrating financial responsibility through a guaranty shall submit the guaranty worded identically to the form available from the department. The guarantor shall comply with all provisions of subdivision 1 of this subsection for self-insurance and also comply with all requirements in the Guaranty Form Furnished as Evidence of Financial Responsibility in Respect of Liability for Discharge of Oil available from the department.
D. To obtain exemption from the cash deposit requirements:
1. The operator shall have and maintain an agent for service of process in the Commonwealth;
2. Any insurer, guarantor, or surety shall have and maintain an agent for service of process in the Commonwealth;
3. Any insurer must be authorized by the Commonwealth of Virginia to engage in the insurance business; and
4. Any instrument of insurance, guaranty or surety must provide that actions may be brought on such instrument of insurance, guaranty or surety directly against the insurer, guarantor or surety for any violation by the operator of Article 11 (§ 62.1-33.34:14 et seq.) of Chapter 3.1 of Title 62.1 of the Code of Virginia up to, but not exceeding, the amount insured, guaranteed or otherwise pledged.
5. All forms of evidence of financial responsibility shall be accompanied by an endorsement that certifies that the insurance policy, evidence of self-insurance, surety or guaranty provides liability coverage for the tank vessels in the amount required by § 62.1-44.34:16 of the Code of Virginia and subsection A of this section.
6. Subdivisions 2, 3 and 4 of this subsection do not apply to operators providing evidence of financial responsibility in accordance with subdivision C 1 of this section.
E. Any operator whose financial responsibility is accepted under this chapter shall notify the board at least 30 days before the effective date of a change, expiration or cancellation of any instrument of insurance, guaranty or surety.
F. The board's approval of evidence of financial responsibility shall expire:
1. One year from the date that the board exempts an operator from the cash deposit requirement based on acceptance of evidence of self-insurance;
2. On the effective date of any change in the operator's instrument of insurance, guaranty or surety; or
3. Upon the expiration or cancellation of any instrument of insurance, guaranty or surety.
G. All nonexempt tank vessel operators shall file with the board the Application for Approval of Evidence of Tank Vessel Financial Responsibility which identifies the tank vessel operator and agent for service of process by name and address, provides identifying information on the tank vessel or vessels and certifies to the board that the information is true and accurate for approval of the evidence of financial responsibility. This form is available. This form shall be submitted with the required evidence of financial responsibility (cash deposit, proof of insurance, self-insurance, guaranty or surety), and shall be completed as far as it pertains to the tank vessel. The operator must sign and date the certification statement on the application form. If the operator is a corporation, the application form must be signed by an authorized corporate official; if the operator is a municipality, state, federal or other public agency, the application form must be signed by an authorized executive officer or ranking elected official; if the operator is a partnership or sole proprietorship, the application form must be signed by a general partner or the sole proprietor.
H. Application for renewal of approval of tank vessel financial responsibility shall be filed with the board 30 days prior to the date of expiration.
I. All applications and written communications concerning changes, submissions and updates required by this chapter, with the exception of applications and submissions accompanied by fees as addressed in subsection K of this section, shall be addressed as follows:
Mailing Address:
Virginia Department of Environmental Quality
Office of Spill Response and Remediation
P.O. Box 10009 1105
Richmond, VA 23240 23218
Location Address:
Virginia Department of Environmental Quality
Office of Spill Response and Remediation
629 East Main Street
Richmond, VA 23219
All applications and submissions accompanied by fees as addressed in subsection K of this section shall be sent to the address listed in subdivision K 2.
J. The board, after notice and opportunity for hearing, may revoke its acceptance of evidence of financial responsibility if it determines that:
1. Acceptance has been procured by fraud or misrepresentation; or
2. A change in circumstances has occurred that would warrant denial of acceptance of evidence of financial responsibility.
K. An application for approval of the demonstration of financial responsibility will be accepted only when the fees established by this section have been paid.
1. Fees shall only be paid upon initial submittal of the demonstration of financial responsibility by an operator to the board. Renewals or changes are not subject to the administrative fee.
2. Fees shall be paid in United States currency by check, draft or postal money order made payable to Treasurer of Virginia. All fees and accompanying applications and submissions shall be sent to:
Mailing Address:
Virginia Department of Environmental Quality
Office of Financial Management
P.O. Box 10150 1105
Richmond, VA 23240 23218
Location Address:
Virginia Department of Environmental Quality
Office of Financial Management
629 East Main Street
Richmond, VA 23219
3. Application fees for approval of evidence of financial responsibility for tank vessels are as follows:
a. Applicants shall pay an application fee of $120.
b. Applicants shall pay a fee of $30 for each additional tank vessel requiring a copy of the accepted evidence of financial responsibility.
4. Application fees are refundable upon receipt of a written notice of withdrawal; of the proffer of financial responsibility and a request for refund received by the department no later than 30 days after submittal and prior to approval.
5. Overpayments of application fees are refundable upon written request. Overpayments not refunded will be credited for the applicant's future use under this section.
9VAC25-260-155. Ammonia surface water quality criteria.
A. The one-hour average concentration of total ammonia nitrogen (in mg N/L) in freshwater shall not exceed, more than once every three years on the average1, the acute criteria below:
| Acute Ammonia Freshwater Criteria
Total Ammonia Nitrogen (mg N/L) |
| pH | Trout Present | Trout Absent |
| 6.5 | 32.6 | 48.8 |
| 6.6 | 31.3 | 46.8 |
| 6.7 | 29.8 | 44.6 |
| 6.8 | 28.1 | 42.0 |
| 6.9 | 26.2 | 39.1 |
| 7.0 | 24.1 | 36.1 |
| 7.1 | 22.0 | 32.8 |
| 7.2 | 19.7 | 29.5 |
| 7.3 | 17.5 | 26.2 |
| 7.4 | 15.4 | 23.0 |
| 7.5 | 13.3 | 19.9 |
| 7.6 | 11.4 | 17.0 |
| 7.7 | 9.65 | 14.4 |
| 7.8 | 8.11 | 12.1 |
| 7.9 | 6.77 | 10.1 |
| 8.0 | 5.62 | 8.40 |
| 8.1 | 4.64 | 6.95 |
| 8.2 | 3.83 | 5.72 |
| 8.3 | 3.15 | 4.71 |
| 8.4 | 2.59 | 3.88 |
| 8.5 | 2.14 | 3.20 |
| 8.6 | 1.77 | 2.65 |
| 8.7 | 1.47 | 2.20 |
| 8.8 | 1.23 | 1.84 |
| 8.9 | 1.04 | 1.56 |
| 9.0 | 0.885 | 1.32 |
The acute criteria for trout present shall apply to all Class V-Stockable Trout Waters and Class VI-Natural Trout Waters as listed in 9VAC25-260-390 through 9VAC25-260-540.
To calculate total ammonia nitrogen acute criteria values in freshwater at different pH values than those listed in this subsection, use the following formulas:
Where trout are present: Acute Criterion Concentration (mg N/L) =
| | 0.275 | + | 39.0 |
| | (1 + 107.204-pH) | (1 + 10pH-7.204) |
Or where trout are absent: Acute Criterion Concentration (mg N/L) =
| | 0.411 | + | 58.4 |
| | (1 + 107.204-pH) | (1 + 10pH-7.204) |
1The default design flow for calculating steady state waste load allocations for the acute ammonia criterion is the 1Q10 (see 9VAC25-260-140 B footnote 10) unless statistically valid methods are employed which demonstrate compliance with the duration and return frequency of the water quality criteria.
B. The 30-day average concentration of total ammonia nitrogen (in mg N/L) where early life stages of fish are present in freshwater shall not exceed, more than once every three years on the average2, the chronic criteria below:
Chronic Ammonia Freshwater Criteria
Early Life Stages of Fish Present
Total Ammonia Nitrogen (mg N/L)
| | Temperature (°C) |
| pH | 0 | 14 | 16 | 18 | 20 | 22 | 24 | 26 | 28 | 30 |
| 6.5 | 6.67 | 6.67 | 6.06 | 5.33 | 4.68 | 4.12 | 3.62 | 3.18 | 2.80 | 2.46 |
| 6.6 | 6.57 | 6.57 | 5.97 | 5.25 | 4.61 | 4.05 | 3.56 | 3.13 | 2.75 | 2.42 |
| 6.7 | 6.44 | 6.44 | 5.86 | 5.15 | 4.52 | 3.98 | 3.50 | 3.07 | 2.70 | 2.37 |
| 6.8 | 6.29 | 6.29 | 5.72 | 5.03 | 4.42 | 3.89 | 3.42 | 3.00 | 2.64 | 2.32 |
| 6.9 | 6.12 | 6.12 | 5.56 | 4.89 | 4.30 | 3.78 | 3.32 | 2.92 | 2.57 | 2.25 |
| 7.0 | 5.91 | 5.91 | 5.37 | 4.72 | 4.15 | 3.65 | 3.21 | 2.82 | 2.48 | 2.18 |
| 7.1 | 5.67 | 5.67 | 5.15 | 4.53 | 3.98 | 3.50 | 3.08 | 2.70 | 2.38 | 2.09 |
| 7.2 | 5.39 | 5.39 | 4.90 | 4.31 | 3.78 | 3.33 | 2.92 | 2.57 | 2.26 | 1.99 |
| 7.3 | 5.08 | 5.08 | 4.61 | 4.06 | 3.57 | 3.13 | 2.76 | 2.42 | 2.13 | 1.87 |
| 7.4 | 4.73 | 4.73 | 4.30 | 3.78 | 3.32 | 2.92 | 2.57 | 2.26 | 1.98 | 1.74 |
| 7.5 | 4.36 | 4.36 | 3.97 | 3.49 | 3.06 | 2.69 | 2.37 | 2.08 | 1.83 | 1.61 |
| 7.6 | 3.98 | 3.98 | 3.61 | 3.18 | 2.79 | 2.45 | 2.16 | 1.90 | 1.67 | 1.47 |
| 7.7 | 3.58 | 3.58 | 3.25 | 2.86 | 2.51 | 2.21 | 1.94 | 1.71 | 1.50 | 1.32 |
| 7.8 | 3.18 | 3.18 | 2.89 | 2.54 | 2.23 | 1.96 | 1.73 | 1.52 | 1.33 | 1.17 |
| 7.9 | 2.80 | 2.80 | 2.54 | 2.24 | 1.96 | 1.73 | 1.52 | 1.33 | 1.17 | 1.03 |
| 8.0 | 2.43 | 2.43 | 2.21 | 1.94 | 1.71 | 1.50 | 1.32 | 1.16 | 1.02 | 0.897 |
| 8.1 | 2.10 | 2.10 | 1.91 | 1.68 | 1.47 | 1.29 | 1.14 | 1.00 | 0.879 | 0.773 |
| 8.2 | 1.79 | 1.79 | 1.63 | 1.43 | 1.26 | 1.11 | 0.973 | 0.855 | 0.752 | 0.661 |
| 8.3 | 1.52 | 1.52 | 1.39 | 1.22 | 1.07 | 0.941 | 0.827 | 0.727 | 0.639 | 0.562 |
| 8.4 | 1.29 | 1.29 | 1.17 | 1.03 | 0.906 | 0.796 | 0.700 | 0.615 | 0.541 | 0.475 |
| 8.5 | 1.09 | 1.09 | 0.990 | 0.870 | 0.765 | 0.672 | 0.591 | 0.520 | 0.457 | 0.401 |
| 8.6 | 0.920 | 0.920 | 0.836 | 0.735 | 0.646 | 0.568 | 0.499 | 0.439 | 0.386 | 0.339 |
| 8.7 | 0.778 | 0.778 | 0.707 | 0.622 | 0.547 | 0.480 | 0.422 | 0.371 | 0.326 | 0.287 |
| 8.8 | 0.661 | 0.661 | 0.601 | 0.528 | 0.464 | 0.408 | 0.359 | 0.315 | 0.277 | 0.244 |
| 8.9 | 0.565 | 0.565 | 0.513 | 0.451 | 0.397 | 0.349 | 0.306 | 0.269 | 0.237 | 0.208 |
| 9.0 | 0.486 | 0.486 | 0.442 | 0.389 | 0.342 | 0.300 | 0.264 | 0.232 | 0.204 | 0.179 |
To calculate total ammonia nitrogen chronic criteria values in freshwater when fish early life stages are present at different pH and temperature values than those listed in this subsection, use the following formulas:
Chronic Criteria Concentration =
| | ( | 0.0577 | + | 2.487 | ) | x MIN |
| (1 + 107.688-pH) | (1 + 10pH-7.688) |
Where MIN = 2.85 or 1.45 x 100.028(25-T), whichever is less.
T = temperature in °C
2The default design flow for calculating steady state waste load allocations for the chronic ammonia criterion where early life stages of fish are present is the 30Q10 (see 9VAC25-260-140 B footnote 10) unless statistically valid methods are employed which demonstrate compliance with the duration and return frequency of the water quality criteria.
C. The 30-day average concentration of total ammonia nitrogen (in mg N/L) where early life stages of fish are absent (procedures for making this determination are in subdivisions 1 through 4 of this subsection) in freshwater shall not exceed, more than once every three years on the average3, the chronic criteria below:
Chronic Ammonia Freshwater Criteria
Early Life Stages of Fish Absent
Total Ammonia Nitrogen (mg N/L)
| | Temperature (°C) |
| pH | 0-7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
| 6.5 | 10.8 | 10.1 | 9.51 | 8.92 | 8.36 | 7.84 | 7.35 | 6.89 | 6.46 | 6.06 |
| 6.6 | 10.7 | 9.99 | 9.37 | 8.79 | 8.24 | 7.72 | 7.24 | 6.79 | 6.36 | 5.97 |
| 6.7 | 10.5 | 9.81 | 9.20 | 8.62 | 8.08 | 7.58 | 7.11 | 6.66 | 6.25 | 5.86 |
| 6.8 | 10.2 | 9.58 | 8.98 | 8.42 | 7.90 | 7.40 | 6.94 | 6.51 | 6.10 | 5.72 |
| 6.9 | 9.93 | 9.31 | 8.73 | 8.19 | 7.68 | 7.20 | 6.75 | 6.33 | 5.93 | 5.56 |
| 7.0 | 9.60 | 9.00 | 8.43 | 7.91 | 7.41 | 6.95 | 6.52 | 6.11 | 5.73 | 5.37 |
| 7.1 | 9.20 | 8.63 | 8.09 | 7.58 | 7.11 | 6.67 | 6.25 | 5.86 | 5.49 | 5.15 |
| 7.2 | 8.75 | 8.20 | 7.69 | 7.21 | 6.76 | 6.34 | 5.94 | 5.57 | 5.22 | 4.90 |
| 7.3 | 8.24 | 7.73 | 7.25 | 6.79 | 6.37 | 5.97 | 5.60 | 5.25 | 4.92 | 4.61 |
| 7.4 | 7.69 | 7.21 | 6.76 | 6.33 | 5.94 | 5.57 | 5.22 | 4.89 | 4.59 | 4.30 |
| 7.5 | 7.09 | 6.64 | 6.23 | 5.84 | 5.48 | 5.13 | 4.81 | 4.51 | 4.23 | 3.97 |
| 7.6 | 6.46 | 6.05 | 5.67 | 5.32 | 4.99 | 4.68 | 4.38 | 4.11 | 3.85 | 3.61 |
| 7.7 | 5.81 | 5.45 | 5.11 | 4.79 | 4.49 | 4.21 | 3.95 | 3.70 | 3.47 | 3.25 |
| 7.8 | 5.17 | 4.84 | 4.54 | 4.26 | 3.99 | 3.74 | 3.51 | 3.29 | 3.09 | 2.89 |
| 7.9 | 4.54 | 4.26 | 3.99 | 3.74 | 3.51 | 3.29 | 3.09 | 2.89 | 2.71 | 2.54 |
| 8.0 | 3.95 | 3.70 | 3.47 | 3.26 | 3.05 | 2.86 | 2.68 | 2.52 | 2.36 | 2.21 |
| 8.1 | 3.41 | 3.19 | 2.99 | 2.81 | 2.63 | 2.47 | 2.31 | 2.17 | 2.03 | 1.91 |
| 8.2 | 2.91 | 2.73 | 2.56 | 2.40 | 2.25 | 2.11 | 1.98 | 1.85 | 1.74 | 1.63 |
| 8.3 | 2.47 | 2.32 | 2.18 | 2.04 | 1.91 | 1.79 | 1.68 | 1.58 | 1.48 | 1.39 |
| 8.4 | 2.09 | 1.96 | 1.84 | 1.73 | 1.62 | 1.52 | 1.42 | 1.33 | 1.25 | 1.17 |
| 8.5 | 1.77 | 1.66 | 1.55 | 1.46 | 1.37 | 1.28 | 1.20 | 1.13 | 1.06 | 0.990 |
| 8.6 | 1.49 | 1.40 | 1.31 | 1.23 | 1.15 | 1.08 | 1.01 | 0.951 | 0.892 | 0.836 |
| 8.7 | 1.26 | 1.18 | 1.11 | 1.04 | 0.976 | 0.915 | 0.858 | 0.805 | 0.754 | 0.707 |
| 8.8 | 1.07 | 1.01 | 0.944 | 0.885 | 0.829 | 0.778 | 0.729 | 0.684 | 0.641 | 0.601 |
| 8.9 | 0.917 | 0.860 | 0.806 | 0.756 | 0.709 | 0.664 | 0.623 | 0.584 | 0.548 | 0.513 |
| 9.0 | 0.790 | 0.740 | 0.694 | 0.651 | 0.610 | 0.572 | 0.536 | 0.503 | 0.471 | 0.442 |
At 15°C and above, the criterion for fish early life stages absent is the same as the criterion for fish early life stages present.
To calculate total ammonia nitrogen chronic criteria values in freshwater when fish early life stages are absent at different pH and temperature values than those listed in this subsection, use the following formulas:
Chronic Criteria Concentration =
| | ( | 0.0577 | + | 2.487 | ) | x 1.45(100.028(25-MAX)) |
| (1 + 107.688-pH) | (1 + 10pH-7.688) |
MAX = temperature in °C or 7, whichever is greater.
3The default design flow for calculating steady state waste load allocations for the chronic ammonia criterion where early life stages of fish are absent is the 30Q10 (see 9VAC25-260-140 B footnote 10) unless statistically valid methods are employed that demonstrate compliance with the duration and return frequency of the water quality criteria.
1. Site-specific modifications to the ambient water quality criteria for ammonia to account for the absence of early life stages of fish shall be conducted in accordance with the procedures contained in this subdivision. Because the department presumes that most state waterbodies have early life stages of fish present during most times of the year, the criteria shall be calculated assuming early life stages of fish are present using subsection B of this section unless the following demonstration that early life stages are absent is successfully completed. Early life stages of fish are defined in subdivision 2 of this subsection. Modifications to the ambient water quality criteria for ammonia based on the presence or absence of early life stages of fish shall only apply at temperatures below 15°C.
a. During the review of any new or existing activity that has a potential to discharge ammonia in amounts that may cause or contribute to a violation of the ammonia criteria contained in subsection B of this section, the department may examine data from the following approved sources in subdivisions 1 a (1) through (5) of this subsection or may require the gathering of data in accordance with subdivisions 1 a (1) through (5) on the presence or absence of early life stages of fish in the affected waterbody.
(1) Species and distribution data contained in the Virginia Department of Game and Inland Fisheries Wildlife Information System database.
(2) Species and distribution data contained in Freshwater Fishes of Virginia, 1994.
(3) Data and fish species distribution maps contained in Handbook for Fishery Biology, Volume 3, 1997.
(4) Field data collected in accordance with U.S. EPA's Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers, Second Edition, EPA 841-B-99-002. Field data must comply with all quality assurance/quality control criteria.
(5) The American Society for Testing and Materials (ASTM) Standard E-1241-88, Standard Guide for Conducting Early Life-Stage Toxicity Tests with Fishes.
b. If data or information from sources other than subdivisions 1 a (1) through (5) of this subsection are considered, then any resulting site-specific criteria modifications shall be reviewed and adopted in accordance with the site-specific criteria provisions in 9VAC25-260-140 D, and submitted to EPA for review and approval.
c. If the department determines that the data and information obtained from subdivisions 1 a (1) through (5) of this subsection demonstrate that there are periods of each year when no early life stages are expected to be present for any species of fish that occur at the site, the department shall issue a notice to the public and make available for public comment the supporting data and analysis along with the department's preliminary decision to authorize the site-specific modification to the ammonia criteria. Such information shall include, at a minimum:
(1) Sources of data and information.
(2) List of fish species that occur at the site as defined by subdivision 3 of this subsection.
(3) Definition of the site. Definition of a "site" can vary in geographic size from a stream segment to a watershed to an entire eco-region.
(4) Duration of early life stage for each species in subdivision 1 c (2) of this subsection.
(5) Dates when early life stages of fish are expected to be present for each species in subdivision 1 c (2) of this subsection.
(6) Based on subdivision 1 c (5) of this subsection, identify the dates (beginning date, ending date), if any, where no early life stages are expected to be present for any of the species identified in subdivision 1 c (2) of this subsection.
d. If, after reviewing the public comments received in subdivision 1 c of this subsection and supporting data and information, the department determines that there are times of the year where no early life stages are expected to be present for any fish species that occur at the site, then the applicable ambient water quality criteria for ammonia for those time periods shall be calculated using the table in this subsection, or the formula for calculating the chronic criterion concentration for ammonia when fish early life stages are absent.
e. The department shall maintain a comprehensive list of all sites where the department has determined that early life stages of fish are absent. For each site the list will identify the waterbodies affected and the corresponding times of the year that early life stages are absent. This list is available either upon request from the Office of Water Quality Programs at 629 E. Main Street, Richmond, VA 23219 P.O. Box 1105, Richmond, Virginia 23218 or from the department website http://deq.state.va.us/wqs/ http://www.deq.virginia.gov/wqs.
2. The duration of the "early life stages" extends from the beginning of spawning through the end of the early life stages. The early life stages include the prehatch embryonic period, the post-hatch free embryo or yolk-sac fry, and the larval period, during which the organism feeds. Juvenile fish, which are anatomically similar to adults, are not considered an early life stage. The duration of early life stages can vary according to fish species. The department considers the sources of information in subdivisions 1 a (1) through (5) of this subsection to be the only acceptable sources of information for determining the duration of early life stages of fish under this procedure.
3. "Occur at the site" includes the species, genera, families, orders, classes, and phyla that: are usually present at the site; are present at the site only seasonally due to migration; are present intermittently because they periodically return to or extend their ranges into the site; were present at the site in the past or are present in nearby bodies of water, but are not currently present at the site due to degraded conditions, and are expected to return to the site when conditions improve. "Occur at the site" does not include taxa that were once present at the site but cannot exist at the site now due to permanent physical alteration of the habitat at the site.
4. Any modifications to ambient water quality criteria for ammonia in subdivision 1 of this subsection shall not likely jeopardize the continued existence of any federal or state listed, threatened or endangered species or result in the destruction or adverse modification of such species' critical habitat.
D. The one-hour average concentration of total ammonia nitrogen (in mg N/L) in saltwater shall not exceed, more than once every three years on the average, the acute criteria below:
Acute Ammonia Saltwater Criteria
Total Ammonia Nitrogen (mg N/L)
Salinity = 10 g/kg
| | Temperature °C |
| pH | 0 | 5 | 10 | 15 | 20 | 25 | 30 | 35 |
| 7.00 | 231.9 | 159.8 | 110.1 | 75.88 | 52.31 | 36.08 | 24.91 | 17.21 |
| 7.20 | 146.4 | 100.9 | 69.54 | 47.95 | 33.08 | 22.84 | 15.79 | 10.93 |
| 7.40 | 92.45 | 63.73 | 43.94 | 30.32 | 20.94 | 14.48 | 10.03 | 6.97 |
| 7.60 | 58.40 | 40.28 | 27.80 | 19.20 | 13.28 | 9.21 | 6.40 | 4.47 |
| 7.80 | 36.92 | 25.48 | 17.61 | 12.19 | 8.45 | 5.88 | 4.11 | 2.89 |
| 8.00 | 23.37 | 16.15 | 11.18 | 7.76 | 5.40 | 3.78 | 2.66 | 1.89 |
| 8.20 | 14.81 | 10.26 | 7.13 | 4.97 | 3.48 | 2.46 | 1.75 | 1.27 |
| 8.40 | 9.42 | 6.54 | 4.57 | 3.20 | 2.27 | 1.62 | 1.18 | 0.87 |
| 8.60 | 6.01 | 4.20 | 2.95 | 2.09 | 1.50 | 1.09 | 0.81 | 0.62 |
| 8.80 | 3.86 | 2.72 | 1.93 | 1.39 | 1.02 | 0.76 | 0.58 | 0.46 |
| 9.00 | 2.51 | 1.79 | 1.29 | 0.95 | 0.71 | 0.55 | 0.44 | 0.36 |
Salinity = 20 g/kg
| | Temperature °C |
| pH | 0 | 5 | 10 | 15 | 20 | 25 | 30 | 35 |
| 7.00 | 247.6 | 170.5 | 117.5 | 80.98 | 55.83 | 38.51 | 26.58 | 18.36 |
| 7.20 | 156.3 | 107.7 | 74.21 | 51.17 | 35.30 | 24.37 | 16.84 | 11.66 |
| 7.40 | 98.67 | 68.01 | 46.90 | 32.35 | 22.34 | 15.44 | 10.70 | 7.43 |
| 7.60 | 62.33 | 42.98 | 29.66 | 20.48 | 14.17 | 9.82 | 6.82 | 4.76 |
| 7.80 | 39.40 | 27.19 | 18.78 | 13.00 | 9.01 | 6.26 | 4.37 | 3.07 |
| 8.00 | 24.93 | 17.23 | 11.92 | 8.27 | 5.76 | 4.02 | 2.83 | 2.01 |
| 8.20 | 15.80 | 10.94 | 7.59 | 5.29 | 3.70 | 2.61 | 1.86 | 1.34 |
| 8.40 | 10.04 | 6.97 | 4.86 | 3.41 | 2.41 | 1.72 | 1.24 | 0.91 |
| 8.60 | 6.41 | 4.47 | 3.14 | 2.22 | 1.59 | 1.15 | 0.85 | 0.65 |
| 8.80 | 4.11 | 2.89 | 2.05 | 1.47 | 1.07 | 0.80 | 0.61 | 0.48 |
| 9.00 | 2.67 | 1.90 | 1.36 | 1.00 | 0.75 | 0.57 | 0.46 | 0.37 |
Salinity = 30 g/kg
| | Temperature °C |
| pH | 0 | 5 | 10 | 15 | 20 | 25 | 30 | 35 |
| 7.00 | 264.6 | 182.3 | 125.6 | 86.55 | 59.66 | 41.15 | 28.39 | 19.61 |
| 7.20 | 167.0 | 115.1 | 79.31 | 54.68 | 37.71 | 26.03 | 17.99 | 12.45 |
| 7.40 | 105.5 | 72.68 | 50.11 | 34.57 | 23.87 | 16.50 | 11.42 | 7.92 |
| 7.60 | 66.61 | 45.93 | 31.69 | 21.88 | 15.13 | 10.48 | 7.28 | 5.07 |
| 7.80 | 42.10 | 29.05 | 20.07 | 13.88 | 9.62 | 6.68 | 4.66 | 3.27 |
| 8.00 | 26.63 | 18.40 | 12.73 | 8.83 | 6.14 | 4.29 | 3.01 | 2.13 |
| 8.20 | 16.88 | 11.68 | 8.10 | 5.64 | 3.94 | 2.78 | 1.97 | 1.42 |
| 8.40 | 10.72 | 7.44 | 5.18 | 3.63 | 2.56 | 1.82 | 1.31 | 0.96 |
| 8.60 | 6.83 | 4.77 | 3.34 | 2.36 | 1.69 | 1.22 | 0.90 | 0.68 |
| 8.80 | 4.38 | 3.08 | 2.18 | 1.56 | 1.13 | 0.84 | 0.64 | 0.50 |
| 9.00 | 2.84 | 2.01 | 1.45 | 1.06 | 0.79 | 0.60 | 0.47 | 0.39 |
To calculate total ammonia nitrogen acute criteria values in saltwater at different pH and temperature values than those listed in this subsection, use the following formulas:
I =
| | 19.9273S |
| | (1000 - 1.005109S) |
Where I = molal ionic strength of water
S = Salinity ppt (g/kg)
The regression model used to relate I to pKa (negative log of the ionization constant) is
pKa = 9.245 +.138I
pKa as defined by these equations is at 298 degrees Kelvin (25°C). T °Kelvin = °C + 273
To correct for other temperatures:
pKaST = pKaS298 +.0324(298 - T °Kelvin)
The unionized ammonia fraction (UIA) is given by:
The acute ammonia criterion in saltwater is given by:
Multiply the acute value by .822 to get the ammonia-N acute criterion.
E. The 30-day average concentration of total ammonia nitrogen (in mg N/L) in saltwater shall not exceed, more than once every three years on the average, the chronic criteria below:
Chronic Ammonia Saltwater Criteria
Total Ammonia Nitrogen (mg N/L)
Salinity = 10 g/kg
| | Temperature °C |
| pH | 0 | 5 | 10 | 15 | 20 | 25 | 30 | 35 |
| 7.00 | 34.84 | 24.00 | 16.54 | 11.40 | 7.86 | 5.42 | 3.74 | 2.59 |
| 7.20 | 21.99 | 15.15 | 10.45 | 7.20 | 4.97 | 3.43 | 2.37 | 1.64 |
| 7.40 | 13.89 | 9.57 | 6.60 | 4.55 | 3.15 | 2.18 | 1.51 | 1.05 |
| 7.60 | 8.77 | 6.05 | 4.18 | 2.88 | 2.00 | 1.38 | 0.96 | 0.67 |
| 7.80 | 5.55 | 3.83 | 2.65 | 1.83 | 1.27 | 0.88 | 0.62 | 0.43 |
| 8.00 | 3.51 | 2.43 | 1.68 | 1.17 | 0.81 | 0.57 | 0.40 | 0.28 |
| 8.20 | 2.23 | 1.54 | 1.07 | 0.75 | 0.52 | 0.37 | 0.26 | 0.19 |
| 8.40 | 1.41 | 0.98 | 0.69 | 0.48 | 0.34 | 0.24 | 0.18 | 0.13 |
| 8.60 | 0.90 | 0.63 | 0.44 | 0.31 | 0.23 | 0.16 | 0.12 | 0.09 |
| 8.80 | 0.58 | 0.41 | 0.29 | 0.21 | 0.15 | 0.11 | 0.09 | 0.07 |
| 9.00 | 0.38 | 0.27 | 0.19 | 0.14 | 0.11 | 0.08 | 0.07 | 0.05 |
Salinity = 20 g/kg
| | Temperature °C |
| pH | 0 | 5 | 10 | 15 | 20 | 25 | 30 | 35 |
| 7.00 | 37.19 | 25.62 | 17.65 | 12.16 | 8.39 | 5.78 | 3.99 | 2.76 |
| 7.20 | 23.47 | 16.17 | 11.15 | 7.69 | 5.30 | 3.66 | 2.53 | 1.75 |
| 7.40 | 14.82 | 10.22 | 7.04 | 4.86 | 3.36 | 2.32 | 1.61 | 1.12 |
| 7.60 | 9.36 | 6.46 | 4.46 | 3.08 | 2.13 | 1.47 | 1.02 | 0.71 |
| 7.80 | 5.92 | 4.08 | 2.82 | 1.95 | 1.35 | 0.94 | 0.66 | 0.46 |
| 8.00 | 3.74 | 2.59 | 1.79 | 1.24 | 0.86 | 0.60 | 0.43 | 0.30 |
| 8.20 | 2.37 | 1.64 | 1.14 | 0.79 | 0.56 | 0.39 | 0.28 | 0.20 |
| 8.40 | 1.51 | 1.05 | 0.73 | 0.51 | 0.36 | 0.26 | 0.19 | 0.14 |
| 8.60 | 0.96 | 0.67 | 0.47 | 0.33 | 0.24 | 0.17 | 0.13 | 0.10 |
| 8.80 | 0.62 | 0.43 | 0.31 | 0.22 | 0.16 | 0.12 | 0.09 | 0.07 |
| 9.00 | 0.40 | 0.28 | 0.20 | 0.15 | 0.11 | 0.09 | 0.07 | 0.06 |
Salinity = 30 g/kg
| | Temperature °C |
| pH | 0 | 5 | 10 | 15 | 20 | 25 | 30 | 35 |
| 7.00 | 39.75 | 27.38 | 18.87 | 13.00 | 8.96 | 6.18 | 4.27 | 2.95 |
| 7.20 | 25.09 | 17.29 | 11.91 | 8.21 | 5.67 | 3.91 | 2.70 | 1.87 |
| 7.40 | 15.84 | 10.92 | 7.53 | 5.19 | 3.59 | 2.48 | 1.72 | 1.19 |
| 7.60 | 10.01 | 6.90 | 4.76 | 3.29 | 2.27 | 1.57 | 1.09 | 0.76 |
| 7.80 | 6.32 | 4.36 | 3.01 | 2.08 | 1.44 | 1.00 | 0.70 | 0.49 |
| 8.00 | 4.00 | 2.76 | 1.91 | 1.33 | 0.92 | 0.64 | 0.45 | 0.32 |
| 8.20 | 2.53 | 1.75 | 1.22 | 0.85 | 0.59 | 0.42 | 0.30 | 0.21 |
| 8.40 | 1.61 | 1.12 | 0.78 | 0.55 | 0.38 | 0.27 | 0.20 | 0.14 |
| 8.60 | 1.03 | 0.72 | 0.50 | 0.35 | 0.25 | 0.18 | 0.14 | 0.10 |
| 8.80 | 0.66 | 0.46 | 0.33 | 0.23 | 0.17 | 0.13 | 0.10 | 0.08 |
| 9.00 | 0.43 | 0.30 | 0.22 | 0.16 | 0.12 | 0.09 | 0.07 | 0.06 |
To calculate total ammonia nitrogen chronic criteria values in saltwater at different pH and temperature values than those listed in this subsection, use the following formulas:
I =
| | 19.9273S |
| | (1000 - 1.005109S) |
Where I = molal ionic strength of water
S = Salinity ppt (g/kg)
The regression model used to relate I to pKa (negative log of the ionization constant) is
pKa = 9.245 +.138I
pKa as defined by these equations is at 298 degrees Kelvin (25°C). T °Kelvin = °C + 273
To correct for other temperatures:
pKaST = pKaS298 +.0324(298 - T °Kelvin)
The unionized ammonia fraction (UIA) is given by:
The chronic ammonia criterion in saltwater is given by:
Multiply the chronic value by .822 to get the ammonia-N chronic criterion.
VA.R. Doc. No. R12-3137; Filed April 16, 2012, 4:30 p.m.