§ 16.1. General.

 Water quality criteria are the numeric concentrations, levels or surface water conditions that need to be maintained or attained to protect existing and designated uses. They are designed to protect the water uses listed in Chapter 93 (relating to water quality standards). The most sensitive of these protected uses are generally water supply, recreation and fish consumption, and aquatic life related. Therefore, criteria designed to protect these uses will normally protect the other uses listed in Chapter 93. This chapter specifies guidelines and procedures for development of criteria for toxic substances and also lists those criteria which have been developed.

   The provisions of this §  16.1 amended November 17, 2000, effective November 18, 2000, 30 Pa.B. 6111. Immediately preceding text appears at serial page (263002).

DISCUSSION

§ 16.11. Toxic substances.

 (a)  These guidelines cover the Federal Clean Water Act section 307(a) priority pollutants and other toxic substances which the Department determines to be of concern due to their verified presence in wastewater discharges. Priority pollutants are the primary focus of concern because the EPA has determined them to be the most commonly used, persistent and toxic substances in wastewater discharges. They include many heavy metals and solvents.

 (b)  In November 1980, the EPA published criteria for protection of human health and aquatic life for 104 of the 129 priority pollutants. (There are currently 126 priority pollutants since three have subsequently been deleted.) These criteria were developed in accordance with National guidelines summarized in 45 FR 79318 (1980). In several instances, the EPA has updated the criteria or issued new criteria based upon new data. The Department’s procedures for establishing criteria for aquatic life and human health protection for priority pollutants, and other toxics of concern are discussed in this subchapter.

   The provisions of this §  16.11 adopted March 10, 1989, effective March 11, 1989, 19 Pa.B. 1059; amended April 9, 1993, effective April 10, 1993, 23 Pa.B. 1727; amended November 17, 2000, effective November 18, 2000, 30 Pa.B. 6111. Immediately preceding text appears at serial pages (263002) and (239599).

GUIDELINES FOR DEVELOPMENT OF AQUATIC
LIFE CRITERIA

§ 16.21. Acute and chronic protection.

 To provide for protection of aquatic life, it is necessary to consider both chronic, that is, long-term (reproduction, growth, survival) and acute or short-term (survival) concepts. Aquatic life can generally survive excursions of elevated concentrations of a pollutant as long as the excursion is of relatively short duration and does not frequently recur. However, to provide protection over a lifetime, a lower concentration shall be maintained. Thus, each aquatic life criterion consists of two components. The EPA defines these as a criterion maximum concentration (CMC) for acute protection and a criterion continuous concentration (CCC) for chronic protection. Each component is further defined in terms of magnitude (a scientifically derived number), duration (the period of time over which the number must be achieved), and the maximum desired frequency (the number of repetitions per unit time) of occurrence. Consistent with this approach, the Department whenever possible develops acute and chronic criteria and specifies the applicable magnitude and duration. The frequency of occurrence is accounted for through the specification of factors appropriate to the criteria in Chapter 96 (relating to water quality standards implementation).

 The Department will establish criteria for toxic substances to provide for protection of aquatic life in accordance with the following guidelines:

   (1)  For those toxics for which the EPA has developed criteria in accordance with the National guidelines as set forth in ‘‘Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses’’ (1985), the Department will review and evaluate the criteria. If the Department determines that the criteria are adequate to protect indigenous aquatic communities in the State’s waters, these criteria will serve as the basis for establishing total maximum daily loads (TMDLs) under Chapter 96 (relating to water quality standards implementation) or NPDES effluent limitations under Chapter 92 (relating to National Pollutant Discharge Elimination System permitting, monitoring and compliance). If the Department determines that the EPA National criteria are inappropriate, the Department will adjust these criteria in accordance with National guidelines to reflect the levels required for protection of aquatic life in this Commonwealth’s waters.

   (2)  For those toxics identified or expected in a discharge for which the EPA has not developed criteria, the Department will develop criteria using the EPA’s National Guidelines.

   The provisions of this §  16.22 amended November 17, 1995, effective November 18, 1995, 25 Pa.B. 5067; amended December 26, 1997, effective December 27, 1997, 27 Pa.B. 6817; amended November 17, 2000, effective November 18, 2000, 30 Pa.B. 6111. Immediately preceding text appears at serial pages (239599) to (239601).

 The Department will use the following sources of information in establishing criteria for aquatic life protection:

   (1)  United States EPA 1986 Quality Criteria for Water (Goldbook).

   (2)  United States EPA Ambient Water Quality Criteria Development Documents and updates.

   (3)  Aquatic life toxicity data available in the published scientific literature.

   (4)  Aquatic life toxicity data available on EPA computerized databases (for example, aquire, Great Lakes Initiative (GLI) Clearinghouse).

 (a)  The criteria are established to control the toxic portion of a substance in the water column. Depending upon available data, aquatic life criteria for metals are expressed as either dissolved or total recoverable. As information develops, the chemical identifiers for the toxic portion may be added, changed or refined. The criteria form one of the bases for water quality-based effluent limitations, which are expressed as total recoverable metal.

 (b)  Dissolved criteria are indicated in Appendix A, Table 1 with an ‘‘*’’, and have been developed by applying the most current EPA conversion factors to the total recoverable criteria. The EPA factors are listed in the following Conversion Factors Table.

Conversion Factors Table

	Chronic	Acute	Source
Arsenic	1.000 (As3+)	1.000 (As3+)	1,2
Cadmium	1.101672- (ln[H]x0.041838)	1.136672- (ln[H]x0.041838)	2
Chromium VI	0.962	0.982	1,2
Copper	0.960	0.960	1,2
Lead*	1.46203-(ln[H] x0.145712)		2
Mercury	0.85	0.85	1,2
Nickel	0.997	0.998	1,2
Selenium	0.922	0.922	1
Silver	NA	0.85	2
Zinc	0.986	0.978	1,2

 *Conversion factor is for both acute and chronic criteria.

 Source 1—Final Water Quality Guidance for the Great Lakes System (60 FR 15366, March 23, 1995)

 2—Establishment of Numeric Criteria for Priority Pollutants; Revision of Metals Criteria-Interim Final Rule (60 FR 22229, May 4, 1995)

 (c) Chemical translators are used to convert dissolved criteria into effluent limitations which are required by Federal regulations to be expressed as total recoverable metal. The default chemical translator used by the Department is the reciprocal of the conversion factor (listed in the Conversion Factors Table) that was used to determine the dissolved criterion.

 (d)  NPDES dischargers may request alternate effluent limitations by using site-specific water quality characteristics. This is accomplished by performing a site-specific chemical translator study for a dissolved criterion. A water effect ratio (WER) study may also be conducted, based on either total recoverable or dissolved criteria, depending on the form of the criterion.

 (e)  A WER is a factor that expresses the difference between the measures of the toxicity of a substance in laboratory water and the toxicity in site water. The WER provides a mechanism to account for that portion of a metal which is toxic under certain physical, chemical or biological conditions. At this time, WERs are applicable only to certain metals, which are listed by the EPA in “Guidance on the Determination and Use of Water-Effect Ratios for Metals” (February 1994), as amended and updated. Subject to Departmental approval of the testing and its results, the Department will use the WER to establish an alternate site-specific criterion.

 (f)  Chemical translator studies must be conducted in accordance with the EPA’s interim final document, “The Metals Translator: A Guidance for calculating a total recoverable permit limit from a dissolved criterion” (June 1996), as amended and updated.

 (g)  Final reports on the studies shall be submitted to the Department within 60 days of completion. Upon approval of the study results, the Department will use the chemical translator or WER, or both, to determine revised effluent limitations.

   The provisions of this §  16.24 adopted November 17, 1995, effective November 18, 1995, 25 Pa.B. 5067; amended November 17, 2000, effective November 18, 2000, 30 Pa.B. 6111; amended February 11, 2005, effective February 12, 2005, 35 Pa.B. 1223; corrected June 23, 2006, effective February 12, 2005, 36 Pa.B. 3117. Immediately preceding text appears at serial pages (309663) to (309664).

GUIDELINES FOR DEVELOPMENT OF HUMAN
HEALTH-BASED CRITERIA

§ 16.31. Application.

 (a)  A threshold effect is defined as an adverse impact that occurs in the exposed individual only after a physiological reserve is depleted. For these effects there exists a dose below which no adverse response will occur. Threshold toxic effects include most systemic effects and developmental toxicity, including teratogenicity. Developmental toxicity includes all adverse effects in developing offspring resulting from prenatal exposure to a causative agent.

 (b)  Control of threshold toxics is based upon animal testing or epidemiological studies that report no- or lowest-observed adverse effect levels of the substance (NOAEL or LOAEL). In evaluating a particular toxic, toxicologists weigh the merits of all the tests, and choose, in their best professional judgment, the safe level. By applying standard margins of safety to the NOAEL, extrapolations from the laboratory animals to humans (factor of 10), for sensitive subpopulations (10), and from short-term to chronic studies (10) can be taken into account. An additional factor of 10 is used if only a LOAEL is available. Modifying factors (1-10), which account for deficiencies in the toxicity studies, are also considered in determining an acceptable exposure level. The current term for this acceptable level is reference dose (RfD); it was previously called the acceptable daily intake (ADI). The RfD is adjusted for protection of an average (70 Kg) person. It is then divided by expected exposure condition to result in an applicable criterion. Except as provided in §  16.61(b)(2) (relating to special provisions for the Great Lakes System), exposure conditions via water include 2 liters per day of drinking water and consumption of 6.5 grams of fish per day. Bioaccumulation of toxics in edible portions of fish is accounted for by use of bioaccumulation factors (BAF). BAF is the ratio in liters per kilogram of a substance’s concentration in tissues of an aquatic organism to its concentration in the ambient water, in situations where both the organism and its food are exposed and the ratio does not change substantially over time.

 (c)  The Department will establish criteria for threshold toxics in accordance with the following guidelines:

   (1)  If the EPA has developed criteria, the Department will evaluate and accept the criteria when it is determined that they are adequate to protect the designated water uses.

   (2)  If the EPA criteria have been evaluated, and have been determined to be inadequate to protect designated uses, or when no criteria have been developed for a substance identified or expected in a discharge, the Department will develop criteria following EPA’s standard toxicological procedures outlined in Exhibit 3-1 of the Water Quality Standards Handbook, Second Edition, EPA 823-0-94-005A, August, 1994, as amended and updated.

   (3)  If no data are available to characterize the human health hazard of a chemical, no criterion will be developed. A criterion to protect the next most sensitive use will be used. A threshold criterion will be developed at a future date if information becomes available.

 (d)  The sources the Department uses to obtain relevant risk assessment values for protection for threshold level toxic effects to human health are as follows:

   (1)  Verified reference doses, listed in the EPA agency-wide supported data system known as IRIS (Integrated Risk Information System).

   (2)  Maximum Contaminant Level Goals (MCLGs).

   (3)  The EPA’s CWA §  304(a) health criteria listed under the National Toxics Rule at 40 CFR 131.36 (57 FR 80848, December 22, 1992) (relating to toxics criteria for those States not complying with Clean Water Act section 303(c)(2)(B)), as amended and updated and other final criteria published by the EPA and the Great Lakes Initiative Clearinghouse.

   (4)  Teratology and other data that have been peer-reviewed may provide information for criteria development.

   The provisions of this §  16.32 adopted March 10, 1989, effective March 11, 1989, 19 Pa.B. 1059; amended April 9, 1993, effective April 10, 1993, 23 Pa.B. 1727; amended December 26, 1997, effective December 27, 1997, 27 Pa.B. 6817; amended November 17, 2000, effective November 18, 2000, 30 Pa.B. 6111. Immediately preceding text appears at serial pages (239603) to (239605).

 (a)  A nonthreshold effect is defined as an adverse impact, including cancer, for which no exposure greater than zero assures protection to the exposed individual. Thus, in contrast to the threshold concept discussed in §  16.32 (relating to threshold level toxic effects), the nonthreshold approach to toxics control is based upon the premise that there is no safe concentration of the toxic.

 (b)  The Department has determined that the regulation of carcinogens from a water quality perspective in accordance with the procedure specified in the following subsections will adequately and reasonably protect human health.

 (c)  The Department accepts the evaluation and extrapolation modeling used by the EPA to quantitate the carcinogenic risk of particular chemicals. Cancer risk level criteria are, therefore, adaptations of the EPA’s cancer potency (slope) factors. Criteria based on cancer risk levels are average lifetime exposure values.

 (d)  The Department’s water quality toxics management program controls carcinogens to an overall risk management level of one excess case of cancer in a population of one million (1 x 10^-6). Expressing this another way, the probability of an individual getting cancer from an ambient water exposure to a carcinogen is increased by a factor of one in one million. This level appears to be protective of human health to a significant degree when compared to other risks encountered in life.

 (e)  The Department uses a 1 x 10^-6 cancer risk level as specified in §  93.8a(d) (relating to toxic substances). Attainment of this risk level is predicated on exposure that includes drinking 2 liters of water and ingesting 6.5 grams of fish per day over a 70-year lifetime, except as provided in §  16.61(b)(2) (relating to special provisions for the Great Lakes Systems). Bioaccumulation of carcinogenic toxics in edible portions of fish are accounted for by use of bioaccumulation factors (BAFs).

 (f)  The Department will use the following guidelines in establishing criteria for nonthreshold toxics:

   (1)  The determination as to whether a substance is a carcinogen will be its identification by the EPA.

   (2)  For toxics for which (cancer potency) slope factors have been developed as evidenced by listing on IRIS the Department will either use the EPA developed criteria or will develop criteria based upon these potency factors using the EPA’s Standard Toxicological Procedures outlined in Exhibit 3-2 of the Water Quality Standards Handbook, Second Edition, EPA 823-0-94-005A, August, 1994, as amended and updated.

   (3)  For carcinogens for which cancer potency (slope) factors have not been developed, the Department will use an additional margin of safety (factor of 10) with threshold toxicity data to develop a protective health criterion.

   The provisions of this §  16.33 adopted March 10, 1989, effective March 11, 1989, 19 Pa.B. 1059; amended April 9, 1993, effective April 10, 1993, 23 Pa.B. 1727; amended December 26, 1997, effective December 27, 1997, 27 Pa.B. 6817; amended November 17, 2000, effective November 18, 2000, 30 Pa.B. 6111. Immediately preceding text appears at serial pages (239605) to (239608).

   This section cited in 25 Pa. Code §  16.61 (relating to special provisions for the Great Lakes System).

CRITERIA MODIFICATION

§ 16.41. Changes and additions.

 The criteria in Appendix A, Table 1 for toxic substances are based on the best scientific information currently available. These criteria may, however, be modified if the Department determines upon evaluation of new scientific findings and information that a change is warranted. Submittal of data and information will be considered by the Department for this purpose. Changes and additions to the table will be published annually in the Pennsylvania Bulletin.

   The provisions of this §  16.42 adopted April 9, 1993, effective April 10, 1993, 23 Pa.B. 1728; amended November 17, 1995, effective November 18, 1995, 25 Pa.B. 5067; reserved November 17, 2000, effective November 18, 2000, 30 Pa.B. 6111. Immediately preceding text appears at serial page (239608).

WATER QUALITY CRITERIA
FOR TOXIC SUBSTANCES

§ 16.51. Human health and aquatic life criteria.

 (a)  Appendix A, Table 1 lists the human health and aquatic life criteria for toxic substances which the Department uses in development of effluent limitations in NPDES Permits and for other purposes. The human health criteria, which include exposures from drinking water and fish consumption, are further defined as to the specific effect (that is, cancer or threshold health effects). For those aquatic life criteria which are hardness related and specified as a formula, such as several of the heavy metals, the Department will use the specific hardness of the receiving stream after mixing with the waste discharge in calculating criteria on a case-by-case basis. The priority pollutant numbers (PP NO) used by the EPA to identify priority pollutants are included in Table 1 for reference purposes. Some of these criteria may be superseded for the Delaware Estuary, Ohio River Basin, Lake Erie Basin), and Genesee River Basin under interstate and international compact agreements with the Delaware River Basin Commission, Ohio River Valley Sanitation Commission and International Joint Commission respectively. The criteria in Table 1 do not apply to the Great Lakes System. Water quality criteria for the Great Lakes System are contained in §  16.61 (relating to special provisions for the Great Lakes System). Criteria may be developed for the Great Lakes System for substances other than those listed in §  16.61 under the methodologies in §  16.61(b).

 (b)  If the Department determines that the natural quality of a surface water segment is of lower quality than the applicable criteria listed in Table 1, the natural quality shall constitute the aquatic life criterion for that segment. All draft natural quality determinations shall be published in the Pennsylvania Bulletin and be subject to a minimum 30 day comment period. The Department will maintain a publicly available list of surface waters and parameters where this subsection applies, and will, from time to time, submit appropriate amendments to this chapter.

 The Department may impose WETT requirements on wastewater discharges where it is determined that the testing is necessary to assure the protection of aquatic life. Where WETT is required, the Department will use the criteria of 0.3 TUA (Toxic Units Acute) and 1 TUC (Toxic Units Chronic) as a basis for evaluating test results. WETT shall be conducted in accordance with 40 CFR Part 136 (relating to the establishment of test procedures for the analysis of pollutants), Quality Assurance Quality Control (QA/QC) guidance issued by the Department, or other protocols approved by the Department.

   The provisions of this §  16.52 adopted December 26, 1997, effective December 27, 1997, 27 Pa.B. 6817; amended November 17, 2000, effective November 18, 2000, 30 Pa.B. 6111. Immediately preceding text appears at serial page (239609).

GREAT LAKES SYSTEM

§ 16.61. Special provisions for the Great Lakes System.

 (a)  Definitions. The following words and terms, when used in this section, have the following meanings, unless the context clearly indicates otherwise:

   BAF—Bioaccumulation Factor—The ratio in liters per kilogram of a substance’s concentration in tissues of an aquatic organism to its concentration in the ambient water, when both the organism and its food are exposed and the ratio does not change substantially over time.

   BCC—Bioaccumulative Chemical of Concern—A chemical that has the potential to cause adverse effects which, upon entering the surface waters, by itself or its toxic transformation product, accumulates in aquatic organisms by a human health BAF greater than 1,000, after considering metabolism and other physiochemical properties that might enhance or inhibit bioaccumulation, under the methodology in 40 CFR Part 132 Appendix B (relating to Great Lakes Water Quality Initiative). Current BCCs are listed in 40 CFR 132.6, Table 6 (relating to pollutants of initial focus in the Great Lakes Water Quality Initiative).

   Great Lakes System—The streams, rivers, lakes and other bodies of surface water within the drainage basin of the Great Lakes in this Commonwealth.

 (b)  Water quality criteria for the Great Lakes System.

   (1)  Aquatic life criteria. Aquatic life criteria for toxic substances in the Great Lakes System will be developed under the methodologies in §  16.22 (relating to criteria development) to the extent they are consistent with 40 CFR Part 132, Appendix A (relating to Great Lakes Water Quality Initiative methodologies for developments of aquatic life values). If there are insufficient data to develop aquatic life criteria for a toxic substance identified in a discharge into these waters, the Department will develop or require a discharger to develop, subject to Department approval, protective aquatic life values using the methodologies in 40 CFR Part 132, Appendix A and guidance issued by the Department. For non-BCCs, WETT may be used in lieu of Tier II values to determine aquatic toxicity.

   (2)  Human health criteria. Human health criteria for the Great Lakes System will be developed using the methods in § §  16.32 and 16.33 (relating to threshold level toxic effects; and nonthreshold effects (cancer)), except that fish consumption is 15 grams per day. If there are insufficient data to develop human health threshold criteria for a toxic substance identified in a discharge into these waters, the Department will develop, or require the discharger to develop, subject to Department approval, protective human health values using the methodologies in 40 CFR Part 132, Appendix C, Section III, as it relates to Tier II values, and guidance issued by the Department.

   (3)  BAFs. Human health criteria for BCCs will be developed under the methodologies in 40 CFR Part 132, Appendix B relating to bioaccumulation factors, and will be listed by the EPA in the GLI Clearinghouse. Because substances other than BCCs (Non-BCCs) bioaccumulate to a much lesser degree, BAFs for Non-BCCs are similar to bioconcentration factors (BCFs). Field measured BAFs, or BAFs equal to BCFs will be used for the development of non-BCC criteria in the Great Lakes.

   (4)  Criteria for Great Lakes System. Human health and aquatic life criteria for the Great Lakes System are contained in the following table. For any pollutant not listed in the table, criteria to protect existing and designated uses will be developed by the Department as needed in accordance with this section.

GREAT LAKES AQUATIC LIFE AND HUMAN HEALTH CRITERIA

   (5)  Wildlife criteria. Wildlife criteria will be developed for the BCCs in the Great Lakes System using methodologies contained in the Great Lakes guidance in 40 CFR Part 132, Appendix D (relating to Great Lakes Water Quality Initiative methodology for the development of wildlife criteria). The wildlife criteria are contained in the following table:

GREAT LAKES WILDLIFE CRITERIA TABLE

   (6)  Additional requirements. Additivity of toxic effects for chlorinated dibenzo-p-dioxins and chlorinated dibenzofurans will be accounted for under 40 CFR Part 132, Appendix F, Procedure 4 (relating to Great Lakes Water Quality Initiative implementation procedures).

 (c)  Minimum protections. The Department will follow guidance that is as protective as the final water quality guidance for the Great Lakes System in 40 FR 15366 (March 23, 1995), as updated and amended.

   The provisions of this §  16.61 adopted December 26, 1997, effective December 27, 1997, 27 Pa.B. 6817; amended November 17, 2000, effective November 18, 2000, 30 Pa.B. 6111; amended February 11, 2005, effective February 12, 2005, 35 Pa.B. 1223; corrected March 25, 2005, effective March 7, 1998, 35 Pa.B. 1890. Immediately preceding text appears at serial pages (271875) to (271879).

   This section cited in 25 Pa. Code §  16.32 (relating to threshold level toxic effects); 25 Pa. Code §  16.33 (relating to nonthreshold effects (cancer)); and 25 Pa. Code §  16.51 (relating to human health and aquatic life criteria).