BC Approved Water Quality Guidelines (Criteria)

Table 9. Summary of Water Quality Guidelines for Copper

Water Use	30-day averages µg/L total copper	Maximum µg/L total copper
Raw Drinking Water Supply	—	500 µg/L
Fresh Water Aquatic Life (when average water hardness as CaC0₃ is less than or equal to 50 mg/L)	less than or equal to 2µg/L	(0.094(hardness)+2) µg/L (hardness as mg/L CaCO3)
Fresh Water Aquatic Life (when average water hardness as CaC0₃ is greater than 50 mg/L)	less than or equal to 0.04 (mean hardness) µg/L	(0.094(hardness)+2) µg/L (hardness as mg/L CaCO3)
Wildlife	None proposed	300 µg/L
Livestock Water Supply	None proposed	300 µg/L
Irrigation Water Supply	None proposed	200 µg/L
Recreation and Aesthetics	None proposed	1000 µg/L
Marine and Estuarine Aquatic Life	less than or equal to 2 µg/L	3 µg/L

1. The average is calculated from at least 5 weekly samples taken in a period of 30 days.

2. When detailed knowledge on the the bioavailable forms of copper is available, the form of copper in the guidelines for aquatic life can be modified, as justified by the data.

3. If natural background levels exceed the guidelines for aquatic life, the increase in total copper
above natural levels to be allowed, if any, should be based on site-specific data.

Reference 6

Table 10. Summary of Water Quality Guidelines for Cyanide

Water Use	Strong-acid dissociable cyanide plus thiocyanate µg/L (as CN)	Strong-acid dissociable cyanide µg/L (as CN)	Weak-acid dissociable cyanide µg/L (as CN)
Raw Drinking Water - includes food processing water (maximum at any time)	200 µg/L	Not applicable	Not applicable
Freshwater Aquatic Life (30-day average)	Not applicable	None proposed	less than or equal to 5 µg/L
Freshwater Aquatic Life (maximum at any time)	Not applicable	None proposed	10 µg/L
Marine and Estuarine Aquatic Life (maximum at any time)	Not applicable	None proposed	1 µg/L

1. All characteristics apply to unfiltered water.

2. The average is calculated from at least 5 weekly samples taken in a period of 30 days.

3. Measure strong-acid dissociable cyanide in addition to weak-acid dissociable cyanide. If tests show that strong-acid dissociable cyanide is greater than the guidelines for weak-acid dissociable cyanide, further sampling of the receiving water is recommended at the same site during bright sunlight, and from sites further from the cyanide source.

4. If it can be shown for a particular water supply, that treatment methods (chlorination, ozonation or ultraviolet irradiation) do not produce free cyanide or cyanogen chloride from the dissociation of thiocyanate, then the guideline should apply only to strong-acid dissociable cyanide.

Reference 7

Table 11. Summary of Water Quality Guidelines for Lead

Water Use	30-day average (µg/L total lead)	maximum (µg/L total lead)
Drinking Water Supply	None proposed	10 µg/L total lead
Fresh Water Aquatic Life (water hardness as CaCO₃ less than or equal to 8 mg/L)	None proposed	3 µg/L total lead
Fresh Water Aquatic Life (water hardness as CaCO₃ greater than 8 mg/L)	less than or equal to 3.31 + _e(1.273 ln [mean hardness] - 4.704)	_e(1.273 ln [hardness] - 1.460)
Wildlife Water Supply	None proposed	100 µg/L total lead
Livestock Water Supply	None proposed	100 µg/L total lead
Marine and Estuarine Aquatic Life	less than or equal to 2 µg/L total lead — (80% of the values less than or equal to 3 µg/L total lead)	140 µg/L total lead
Irrigation Water Supply (neutral and alkaline fine-textured soils)	None proposed	400 µg/L total lead
Irrigation Water Supply (all other soils)	None proposed	200 µg/L total lead
Industrial Water Supply (food processing industry)	None proposed	50 µg/L total lead
Recreation and Aesthetics	None proposed	50 µg/L total lead

1. The average is calculated from at least 5 weekly samples taken in a period of 30 days.

2. If natural levels exceed the guidelines for aquatic life, the increase in total lead above natural levels to be allowed, if any, should be based on site-specific data.

3. The alert level for total lead in the edible portions of fish and shellfish for human consumption is 0.8 µg/g wet weight. A
site-specific investigation should be done if levels approach or exceed this level.

Reference 8

Table 12. Details of Freshwater Aquatic Life Guidelines for Lead

Water Hardness (mg/L CaCO₃)	30-day average concentration (µg/L total lead)	maximum concentration (µg/L total lead)
less than or equal to 8 mg/L	None proposed	3 µg/L total lead
20 mg/L	4 µg/L	10 µg/L
30 mg/L	4 µg/L	18 µg/L
40 mg/L	4 µg/L	25 µg/L
50 mg/L	5 µg/L	34 µg/L
80 mg/L	6 µg/L	61 µg/L
100 mg/L	6 µg/L	82 µg/L
200 mg/L	11 µg/L	197 µg/L
300 mg/L	16 µg/L	330 µg/L

1. At least 80% of the measurements should be less than or equal to 1.5 times the 30-day average guideline.

Reference 8

Table 13. Summary of Water Quality Guidelines for Mercury

Water Use	30-day average µg/L total Hg	maximum at any time µg/L total Hg
Drinking Water Supply	None proposed	1µg/L
Fresh Water Aquatic Life	0.02 µg/L	0.1 µg/L
Marine and Estuarine Aquatic Life	0.02 µg/L	2.0 µg/L
Wildlife	None proposed	Table 13a
Livestock Water Supply	None proposed	3.0 µg/L
Irrigation Water Supply	None proposed	2.0 µg/L
Primary Contact Recreation	None proposed	1.0 µg/L
Industrial Water Supply - food processing industry	None proposed	1.0 µg/L

1. The average is calculated from at least 5 weekly samples taken in a period of 30 days.

2. If natural levels exceed the guidelines for aquatic life, the increase in total mercury above natural levels to be allowed, if any, should be based on site-specific data.

3. Great Lakes Water Quality Initiative has recommended a guideline of 1.3 nanogram/L for the protection of wildlife (reference 26).

4. These guidelines may not be protective against Hg bioaccumulation in fish tissue; hence, they should be assessed in conjunction with the tissue residue guidelines for Hg in Table 14.

* The maximum guideline for total Hg changes when the MeHg concentration in the environment changes. See Table 13a.

References 9 and 9a

Table 13a. Relationship between Methyl Mercury (MeHg) Concentration in the Environment and the Total Hg Guideline

% MeHg (of Total Hg)	Total Hg guideline in µg/L
<0.5	0.02
1	0.01
2.5	0.004
5	0.002

Table 13b. Tissue Residue Guideline to Protect Wildlife from Hg Toxicity

Maximum concentration of methyl Hg
in fish or shellfish consumed by wildlife

0.033 µg as methyl Hg

References 9 and 9a

Table 14. Variations in (the Mercury) Aquatic Life Guidelines for Fish/Shellfish When the (Human) Diet is Based Primarily on Fish

Concentration of total Hg in the edible portion of fish and shellfish (µg Hg/g wet weight fish)	Safe quantity for weekly consumption on a regular basis (g fish wet weight)
0.5 µg/g	210 g
0.4 µg/g	260 g
0.3 µg/g	350 g
0.2 µg/g	525 g
0.1 µg/g	1050 g

1. The maximum concentration of total Hg in the edible portion of fish/shellfish should not exceed 0.5 µg/g wet weight. For people whose diet is based primarily on fish or shellfish, this guideline may need to be varied as indicated above.

References 9 and 9a

Table 15. Summary of Water Quality Guidelines for Molybdenum

Water Use	30-day averages mg/L total molybdenum	Maximum mg/L total molybdenum
Raw Untreated Drinking Water	None proposed	0.25 mg/L
Fresh Water Aquatic Life	less than or equal to 1 mg/L	2 mg/L
Wildlife	None proposed	0.05 mg/L
Livestock Water Supply (consuming forages not irrigated or if no molybdenum containing fertilizers are applied to grow feed consumed by livestock)	None proposed	0.08 mg/L
Livestock Water Supply (all other cases)	None proposed	0.05 mg/L
Irrigation Water - Poorly Drained Soil - Cu:Mo ratio is less than 2:1 in the irrigation water - (forage crops)	less than or equal to 0.01 mg/L	0.05 mg/L
Irrigation Water - Poorly Drained Soil - Cu:Mo ratio is greater than 2:1 in the irrigation water - (forage crops)	less than or equal to 0.02 mg/L	0.05 mg/L
Irrigation Water - Well Drained Soil (forage crops)	less than or equal to 0.02 mg/L	0.05 mg/L
Irrigation Water - All Soils (non-forage crops)	less than or equal to 0.03 mg/L	None proposed

1. The average is calculated from at least 5 weekly samples taken in a period of 30 days.

Reference 10

Table 16. Summary of Water Quality Guidelines for Nitrogen

Water Use	Nitrate mg/L as nitrogen	Nitrite mg/L as nitrogen	Ammonia (total) mg/L as nitrogen
Drinking Water	10 mg/L (maximum)	1 mg/L (maximum)	None proposed
Fresh Water Aquatic Life - maximum	200 mg/L (maximum)	0.06 mg/L (maximum) when the chloride is less than 2 mg/L - also see Table 17	see Tables 4 and 5
Fresh Water Aquatic Life - average	less than or equal to 40 mg/L (average)	less than or equal to 0.02 mg/L (average) when the chloride is less than 2 mg/L - also see Table 17	see Tables 4 and 5
Marine Aquatic Life - maximum	None proposed	None proposed	see Table 21
Marine Aquatic Life - average	None proposed	None proposed	see Table 22
Livestock Watering	100 mg/L (maximum)	10 mg/L (maximum)	None proposed
Wildlife	100 mg/L (maximum)	10 mg/L (maximum)	None proposed
Recreation and Aesthetics	10 mg/L (maximum)	1 mg/L (maximum)	None proposed

1. The average value is calculated from at least 5 weekly samples taken in a period of 30 days.

2. Where nitrate and nitrite are present, the total nitrate+nitrite nitrogen should not exceed these values.

3. These levels are too high for some amphibians. For example the 96-h LC₅₀ for the eastern American toad is 13.6 mg/L N.

4. Chronic effects are observed at lower levels, 5 to 10 mg/L N (reference 27)

Reference 3

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