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Implementing the Water Environment and Water Services (Scotland) Act 2003: Development of environmental standards and conditions limits - phase II: A Consultation

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ANNEX 13: GROUNDWATER THRESHOLD VALUES

Table A: Threshold values applicable to each of the tests (iii) relevant to the assessment of groundwater chemical status

Electrical conductivityNitrateAtrazineTotal chromiumSimazineMecopropEpoxyconazole

Chemical classification tests

Mean conductivity (micro-Siemens/cm)

Mean NO 3 concentration (mg/l) in the associated transitional water or coastal water

Mean concen-tration (ug/l)

Mean concen-tration (ug/l)

Mean concen-tration (ug/l)

Mean concen-tration (ug/l)

Mean concentration (ug/l)

Test 1 - Saline Intrusion

1000

Test 2a - Surface Water - Diffuse

-

10

-

-

-

-

-

Test 2b - Surface Water - Point Source

Test 3 - Drinking Water Protected Areas

31

0.075

-

-

-

-

Test 4 - General Assessment of Quality

31 (i)

0.075 (ii)

37.5

0.075 (ii)

0.075 (ii)

0.075*

Table A (continued)

Dichloromethane

Trichloroethene

Tetrachloroethene

Benzo(a)pyrene

Any pollutant for which a surface water standard has been set

Chemical classification tests

Mean concentration (ug/l)

Mean concentration (ug/l)

Mean concentration (ug/l)

Mean concentration (ug/l)

Test 2b - Surface Water - Point Source

Failure of the standards in the associated surface water

Test 3 - Drinking water Protected Areas

-

-

-

-

-

Test 4 - General Assessment of Quality

1.5

7.5

7.5

0.0075 (ii)

-

Note to Table A

(i)This standard has been designed to be equivalent to 50 mg/l as a 95 -percentile standard

(ii)These standards have been designed to be equivalent to 0.1 ï­ g/l as a 95 -percentile standard

(iii)UKTAG has been unable to develop a methodology for deriving threshold values indicative of risks to terrestrial ecosystems dependent on groundwater. Consequently, threshold values cannot be proposed at this time.

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Page updated: Thursday, June 26, 2008