WQBELs Karen Holligan September 23, 2015

WQBELs – A Four-Piece Puzzle Numerical criteria (toxic pollutants) Water body quality Effluent fraction Bioavailable fraction WQBELs – A Four-Piece Puzzle Numerical criteria (toxic pollutants) Water body quality Effluent fraction Bioavailable fraction

Numerical Criteria for Toxic Pollutants ◊ Found in 30 TAC Chapter 307 – the Texas Surface Water Quality Standards ◊ Table 1 – aquatic life ◊ Table 2 – human health ◊ Criteria revisited every three years Numerical Criteria for Toxic Pollutants Found in 30 TAC Chapter 307 – the Texas Surface Water Quality Standards Table 1 – aquatic life Table 2 – human health Criteria revisited every three years

Numerical Criteria for Toxic Pollutants – Aquatic Life Table 1 in the Standards ◊ Freshwater acute chronic ◊ Saltwater acute chronic Note: Acute toxicity— exposures of ≤ 4 days. Chronic toxicity— exposures of ≥ 7 days. Numerical Criteria for Toxic Pollutants – Aquatic Life Table 1 in the Standards Freshwater acute chronic Saltwater acute Chronic Note: Acute toxicity—exposures of ≤ 4 days. Chronic toxicity—exposures of ≥ 7 days.

◊ Most criteria are for total concentrations. ◊ Some criteria are for dissolved concentrations: aluminum arsenic cadmium chromium (tri and hex) copper lead nickel silver (free ion) zinc Numerical Criteria for Toxic Pollutants – Aquatic Life But wait! Permit limits are written for total concentrations. Numerical Criteria for Toxic Pollutants – Aquatic Life Most criteria are for total concentrations. Some criteria are for dissolved concentrations: aluminum arsenic cadmium chromium (tri and hex) copper lead nickel silver (free ion) zinc But wait! Permit limits are written for total concentrations.

Numerical Criteria for Toxic Pollutants – Aquatic Life ◊ Conversion from dissolved criteria to total limits uses ambient total suspended solids (TSS) of nearest downstream classified segment. ◊ H INT : Dissolved fraction = bioavailable fraction. Numerical Criteria for Toxic Pollutants – Aquatic Life Conversion from dissolved criteria to total limits uses ambient total suspended solids (TSS) of nearest downstream classified segment. H INT : Dissolved fraction = bioavailable fraction.

Numerical Criteria for Toxic Pollutants – Aquatic Life ◊ Freshwater criteria for pentachlorophenol depend on pH of receiving water body. ◊ Pentachlorophenol more toxic at lower pH values. Numerical Criteria for Toxic Pollutants – Aquatic Life

◊ Some freshwater criteria depend on hardness of receiving water body: cadmium chromium (trivalent) copper lead nickel zinc Example: copper Numerical Criteria for Toxic Pollutants – Aquatic Life

◊ These metals are more toxic in soft water, so freshwater criteria are lower at smaller hardness values. Example: copper Segment Number Water Body Name Hardness (mg/L of CaCO 3 ) Acute Criterion (µg/L) Chronic Criterion (µg/L) 0505 Sabine River Above Toledo Bend Reservoir Colorado River Below Lake J. B. Thomas Numerical Criteria for Toxic Pollutants – Aquatic Life These metals are more toxic in soft water, so freshwater criteria are lower at smaller hardness values. Example: copper Segment Number 0505, Sabine River Above Toledo Bend Reservoir: Hardness = 42 milligrams per liter, Acute Criterion = 6.27 micrograms per liter, Chronic Criterion = 4.51 micrograms per liter Segment Number 1412, Colorado River Below Lake J. B. Thomas: Hardness = 310 milligrams per liter, Acute Criterion = 41.2 micrograms per liter, Chronic Criterion = 24.8 micrograms per liter

Numerical Criteria for Toxic Pollutants – Human Health ◊ Table 2 (2014) – Water and Fish Fish Only Water column–based criteria Note: Human health criteria based on - Childhood exposure (non-carcinogens) Lifetime exposure (carcinogens). Numerical Criteria for Toxic Pollutants – Human Health Table 2 (2014) – Water and Fish Fish Only Water column–based criteria Note: Human health criteria based on - Childhood exposure (non-carcinogens) Lifetime exposure (carcinogens).

Water quality data for each classified segment in Procedures to Implement the Texas Surface Water Quality Standards (IP). ◊ TSS ◊ pH ◊ Total hardness ◊ Total dissolved solids (TDS) ◊ Chloride ◊ Sulfate Water Body Quality Water quality data for each classified segment in Procedures to Implement the Texas Surface Water Quality Standards (IP). TSS pH Total hardness Total dissolved solids (TDS) Chloride Sulfate

Water Body Quality ◊ TSS – used to calculate bioavailable fraction of metals ◊ pH – used to calculate freshwater aquatic life criteria for pentachlorophenol ◊ Total hardness – used to calculate freshwater aquatic life criteria for most metals ◊ Chloride – used in calculating bioavailable fraction of silver (freshwater only) Water Body Quality TSS – used to calculate bioavailable fraction of metals pH – used to calculate freshwater aquatic life criteria for pentachlorophenol Total hardness – used to calculate freshwater aquatic life criteria for most metals Chloride – used in calculating bioavailable fraction of silver (freshwater only)

Water Body Quality Critical values of ambient water quality data: ◊ TSS – 15 th percentile ◊ pH – 15 th percentile ◊ Total hardness – 15 th percentile ◊ Chloride – 50 th percentile Water Body Quality Critical values of ambient water quality data: TSS – 15 th percentile pH – 15 th percentile Total hardness – 15 th percentile Chloride – 50 th percentile

Effluent Fraction Critical mixing conditions: ◊ Critical effluent percentages (lakes, bays, estuaries, wide tidal rivers) or ◊ Critical flows (streams, rivers, narrow tidal rivers) Effluent Fraction Critical mixing conditions: Critical effluent percentages (lakes, bays, estuaries, wide tidal rivers) or Critical flows (streams, rivers, narrow tidal rivers)

Effluent Fraction Numerical criteria apply at the edge of each zone: Name of ZoneAcronym Applicable Criteria Zone of Initial Dilution ZID Acute Aquatic Life Aquatic Life Mixing Zone MZ Chronic Aquatic Life Human Health Mixing Zone HHMZHuman Health Effluent Fraction Numerical criteria apply at the edge of each zone: Zone of Initial Dilution (ZID) - Acute Aquatic Life Aquatic Life Mixing Zone (MZ) - Chronic Aquatic Life Human Health Mixing Zone (HHMZ) - Human Health

Effluent Fraction ◊ Regulatory zones and critical effluent percentages for bays, estuaries, and wide tidal rivers If receiving water at discharge point ≥ 400 feet wide: ZID = 50 feet (30%) MZ = 200 feet (8%) HHMZ = 400 feet (4%) Effluent Fraction Regulatory zones and critical effluent percentages for bays, estuaries, and wide tidal rivers If receiving water at discharge point ≥ 400 feet wide: ZID = 50 feet (30%) MZ = 200 feet (8%) HHMZ = 400 feet (4%)

Effluent Fraction ◊ Regulatory zones and critical effluent percentages for lakes If receiving water at discharge point ≥ 200 feet wide: ZID = 25 feet (60%) MZ = 100 feet (15%) HHMZ = 200 feet (8%) Effluent Fraction Regulatory zones and critical effluent percentages for lakes If receiving water at discharge point ≥ 200 feet wide: ZID = 25 feet (60%) MZ = 100 feet (15%) HHMZ = 200 feet (8%)

Effluent Fraction ◊ Regulatory zones and critical flows for streams and rivers MZ ◦ 300' downstream, 100' upstream ◦ 7-day, 2-year low flow (7Q2) ZID ◦ 60' downstream, 20' upstream ◦ 25% of 7Q2 HHMZ ◦ 300' downstream, 100' upstream ◦ Harmonic mean flow (HM) Effluent Fraction Regulatory zones and critical flows for streams and rivers MZ 300' downstream, 100' upstream 7-day, 2-year low flow (7Q2) ZID 60' downstream, 20' upstream 25% of 7Q2 HHMZ 300' downstream, 100' upstream Harmonic mean flow (HM)

Effluent Fraction – Streams and Rivers What is Q E ? Effluent Fraction – Streams and Rivers

Q E = Effluent flow Aquatic life Domestic – final average permitted flow Industrial ◦ new or amendment to increase flow – permitted average flow requested ◦ renewal - highest daily average flow reported in last two years Effluent Fraction – Streams and Rivers Q E = Effluent flow Aquatic life Domestic – final average permitted flow Industrial new or amendment to increase flow – permitted average flow requested renewal - highest daily average flow reported in last two years

Effluent Fraction – Streams and Rivers Q E = Effluent flow Human health Domestic – final average permitted flow Industrial ◦ new or amendment to increase flow – permitted average flow requested ◦ renewal - average daily average flow reported in last two years Effluent Fraction – Streams and Rivers Q E = Effluent flow Human health Domestic – final average permitted flow Industrial new or amendment to increase flow – permitted average flow requested renewal - average daily average flow reported in last two years

Bioavailable Fraction For most metals, numerical criteria for aquatic life are dissolved concentrations, but… effluent limits are expressed as total concentrations. The bioavailable fraction, which is a function of TSS, is used to make this translation. Bioavailable Fraction For most metals, numerical criteria for aquatic life are dissolved concentrations, but… effluent limits are expressed as total concentrations. The bioavailable fraction, which is a function of TSS, is used to make this translation.

Bioavailable Fraction The bioavailable fraction equals: C d C T where: C d = dissolved concentration C T = total concentration This fraction depends on TSS : Bioavailable Fraction

The term K P, the partition coefficient, also depends on TSS: where “b” and “m” are values found in Table 6 in the 2010 IP(p. 160). Bioavailable Fraction

Putting All the Pieces Together Numerical CriteriaWater Body Quality Effluent Fraction Bioavailable Fraction Putting All the Pieces Together Numerical Criteria Water Body Quality Effluent Fraction Bioavailable

Putting All the Pieces Together Three easy steps to calculate WQBELs for aquatic life and human health! ◊ Calculate waste load allocation – WLA ◊ Calculate long-term average – LTA ◊ Calculate effluent limits: daily average (DLY AVG) daily maximum (DLY MAX) Putting All the Pieces Together Three easy steps to calculate WQBELs for aquatic life and human health! Calculate waste load allocation – WLA Calculate long-term average – LTA Calculate effluent limits: daily average (DLY AVG) daily maximum (DLY MAX)

Putting All the Pieces Together – Aquatic Life Calculate WLAs for both acute and chronic aquatic life protection: Putting All the Pieces Together – Aquatic Life

◊ Compare acute and chronic LTAs ◊ Use the smaller LTA to calculate daily average and daily maximum effluent limits based on aquatic life criteria: Putting All the Pieces Together – Aquatic Life

Putting All the Pieces Together – Human Health Calculate WLA for human health protection: Calculate LTA for human health protection: Putting All the Pieces Together – Human Health

Calculate daily average and daily maximum effluent limits based on human health criteria: Putting All the Pieces Together – Human Health

Putting All the Pieces Together – Compare Aquatic Life and Human Health Limits Some pollutants have both aquatic life and human health criteria. ◊Compare limits based on aquatic life with limits based on human health ◊Include the lower concentrations in the permit Putting All the Pieces Together – Compare Aquatic Life and Human Health Limits Some pollutants have both aquatic life and human health criteria. Compare limits based on aquatic life with limits based on human health Include the lower concentrations in the permit

Help! My draft permit includes a new or more stringent WQBEL – what can I do? Call your permit writer! Help! My draft permit includes a new or more stringent WQBEL – what can I do? Call your permit writer!

Why did I get this limit? Big Picture: New limit Average concentration from application is ≥ 85% of calculated daily average WQBEL More stringent limit Calculated WQBELs are more stringent than existing limits Down in the weeds: numerical criteria, water body quality, effluent fraction, bioavailable fraction Why did I get this limit? Big Picture: New limit: Average concentration from application is ≥ 85% of calculated daily average WQBEL More stringent limit: Calculated WQBELs are more stringent than existing limits Down in the weeds: numerical criteria, water body quality, effluent fraction, bioavailable fraction

All Pollutants Effluent fraction – river or stream: ◊ Critical flows Stream type – which criteria apply? ○intermittent – acute (no dilution) ○perennial – chronic, acute, HH ○intermittent with perennial pools – chronic (no dilution), acute (no dilution), HH Stream flows – 7Q2, HM All Pollutants Effluent fraction – river or stream: Critical flows Stream type – which criteria apply? intermittent – acute (no dilution) perennial – chronic, acute, HH intermittent with perennial pools – chronic (no dilution), acute (no dilution), HH Stream flows – 7Q2, HM

All Pollutants Effluent fraction – lake or bay: ◊ Critical mixing conditions Relocate outfall – ○narrow arm smaller mixing zones = larger effluent fractions = lower permit limits ○wider area larger mixing zones = smaller effluent fractions = higher permit limits All Pollutants Effluent fraction – lake or bay: Critical mixing conditions Relocate outfall – narrow arm = smaller mixing zones = larger effluent fractions = lower permit limits wider area = larger mixing zones = smaller effluent fractions = higher permit limits

All Pollutants Numerical Criteria: ◊ Site-specific standard – adopted in Appendix E of the Standards Temporary variance – allows time for permittee to develop comprehensive information to support site- specific standard. ○ Permittee must request variance ○ Permit must show that existing standard may not be appropriate ○ Request included in public notices All Pollutants Numerical Criteria: Site-specific standard – adopted in Appendix E of the Standards Temporary variance – allows time for permittee to develop comprehensive information to support site- specific standard. Permittee must request variance Permit must show that existing standard may not be appropriate Request included in public notices

All Pollutants Numerical Criteria: ◊ Site-specific standard (cont.) Temporary variance (cont.) ○ Must be approved by EPA ○ Three-year permit term ○ Permit language requires a study ○ Variance may be extended ○ Coordinate with TCEQ staff All Pollutants Numerical Criteria: Site-specific standard (cont.) Temporary variance (cont.) Must be approved by EPA Three-year permit term Permit language requires a study Variance may be extended Coordinate with TCEQ staff

Metals (except mercury or selenium) Numerical criteria: ◊ Site-specific standard (cont.) Water-effect ratio (WER): Use whole effluent toxicity testing to account for difference in toxicity in receiving water. ○ This is “w” or “m” factor in Table 1 of Standards ○ Saltwater: ~2; freshwater: ~ ○ Streamlined procedure for copper (freshwater) ○ Coordinate with TCEQ staff Metals (except mercury or selenium) Numerical criteria: Site-specific standard (cont.) Water-effect ratio (WER): Use whole effluent toxicity testing to account for difference in toxicity in receiving water. This is “w” or “m” factor in Table 1 of Standards Saltwater: ~2; freshwater: ~ Streamlined procedure for copper (freshwater) Coordinate with TCEQ staff

Metals Numerical criteria, water body quality ◊ Site-specific hardness: affects criteria for cadmium, trivalent chromium, copper, lead, nickel, and zinc ≥ 30 samples from receiving water upstream of discharge and outside of MZ ≥ 1 week between successive samples Coordinate study design with TCEQ staff Metals Numerical criteria, water body quality Site-specific hardness: affects criteria for cadmium, trivalent chromium, copper, lead, nickel, and zinc ≥ 30 samples from receiving water upstream of discharge and outside of MZ ≥ 1 week between successive samples Coordinate study design with TCEQ staff

Metals Water body quality, bioavailable fraction ◊ Site-specific TSS: affects bioavailable fraction ≥ 30 samples from receiving water upstream of discharge and outside of MZ ≥ 1 week between successive samples Coordinate study design with TCEQ staff Metals Water body quality, bioavailable fraction Site-specific TSS: affects bioavailable fraction ≥ 30 samples from receiving water upstream of discharge and outside of MZ ≥ 1 week between successive samples Coordinate study design with TCEQ staff

Metals Bioavailable fraction ◊ Site-specific ratio of dissolved to total metal concentration ≥ 30 samples from receiving water upstream of discharge and outside of MZ ≥ 1 week between successive samples Mix samples with effluent to equal critical dilution If no water upstream, critical dilution is 100% effluent Metals Bioavailable fraction Site-specific ratio of dissolved to total metal concentration ≥ 30 samples from receiving water upstream of discharge and outside of MZ ≥ 1 week between successive samples Mix samples with effluent to equal critical dilution If no water upstream, critical dilution is 100% effluent

Metals Bioavailable fraction ◊ Site-specific ratio of dissolved to total metal concentration (cont.) Measure total and dissolved metal concentrations Measure TSS of receiving water and effluent each time a sample is collected and mixed with effluent (unless critical dilution is 100%) Coordinate study design with TCEQ staff Metals Bioavailable fraction Site-specific ratio of dissolved to total metal concentration (cont.) Measure total and dissolved metal concentrations Measure TSS of receiving water and effluent each time a sample is collected and mixed with effluent (unless critical dilution is 100%) Coordinate study design with TCEQ staff

Any Questions? We are always full of questions!