§ Mr. MichaelTo ask the Secretary of State for Wales (1) if he will list the watercourses between the Atomic Weapons Research Establishment and the sea which are affected when there is any discharge from that 43W establishment (a) similar to the one which took place on Friday 17 November or (b) in the event of a more serious incident;
(2) what action has been taken by the Welsh region of the NRA following the discharge of chromic acid from the Atomic Weapons Research Establishment in Cardiff on Friday 17 November;
(3) what acutal contamination was identified in each of the watercourses between the Atomic Weapons Research Establishment in Cardiff and the sea following the discharge of chromic acid on Friday 17 November;
(4) what information he has about the discharge of chromic acid to the interceptor which discharges into Llanishen brook from the Atomic Weapons Research Establishment in Cardiff on Friday 17 November.
§ Mr. GristThere is only one receiving water course system from Atomic Weapons Establishment, Cardiff. The immediate receiving water is the Llanishen brook which enters Roath Park lake. The outlet from the lake forms the Roath brook which discharges into the tidal reach of the River Rhymney.
Prompt action by the National Rivers Authority and AWE staff on Friday 17 November resulted in containment of the chromic acid spill in the on-site surface water oil interceptor. The interceptor's contents were tankered off site during the early hours of Saturday morning. Slight seepage from the interceptor into the adjacent watercourse occurred. Samples taken showed the maximum concentration in the immediate watercourse to be 2 milligrammes per litre (mgl). This was not regarded by the National Rivers Authority as significant and did not affect Roath Park lake. However, as a precaution, NRA staff also took samples of the inlet stream to Roath Park lake which contained the following levels of chromium.
- 0.1 mg1 at 2015 hrs. on 17 November 1989.
- 0.04 mg1 at 1900 hrs. on 18 November 1989.
These concentrations are not regarded as significant.
§ Mr. MichaelTo ask the Secretary of State for Wales what are the health and safety implications of any discharge of chromic acid into a watercourse; and what is his assessment of the maximum safe level for(a) humans and (b) fish.
§ Mr. GristChromic acid is an industrial chemical used in metal finishing and is in no way unusual. When diluted in a watercourse, the acid's corrosive properties would be greatly reduced, but it is the chromium content of chromic acid that would normally be of concern. National environmental quality standards (reflecting EC directives) have been set for chromium and are shown in the following table:
Quality Objective Fresh Water Class of River Direct A1 50PT Abstraction to potable supply A2 75MT 44W
Total hardness of water (as mg/1 CaCo3) Protection of 0–50 5AD sensitive aquatic 50–100 10AD life (eg salmonid fish) 100–150 20AD 150–200 20AD 200–250 50AD
Total hardness of water (as mg/1 CaCo3) 250+ 50AD Protection of 0–50 150AD other aquatic life 50–100 175AD (eg cyprinid fish) 100–150 200AD 150–200 200AD 200–250 250AD 250+
Salt Water Protection of salt water life 15AD All values given as microgrammes per litre.
A = Annual average.
P = 95 per cent. of samples.
M = Maximum Allowable Concentration.
D = Dissolved.
T = Total.
In line with the EC directive relating to the quality of water intended for human consumption, the new Water Supply (Water Quality) Regulations 1989 (S.I. 1989 No. 1147) set a maximum concentration of 50 microgrammes of chromium per litre in drinking water.