§ Dr. Roger Thomas
asked the Minister of Agriculture, Fisheries and Food (1) what information he has on the concentration of list II substances in waste disposed of by Thames water authority at sea from (a) Crossness sewage works and (b) Beckton sewage works;
(2) what information he has as to the concentration of list I substances in waste disposed of by Thames water authority at sea from (a) Crossness sewage works and (b) Beckton sewage works:
§ Mr. Gummer
The most recent data available for substances listed in annex I and annex II of the Oslo Convention for the Prevention of Marine Pollution by Dumping from Ships and Aircraft are set out below:
Crossness Beckton Annex I substances Mercury 3 5.5 mg/kg dry solids Cadmium 15 22 mg/kg dry solids Organohalogens: (a) Gamma <0.01 <0.01 mg/litre (wet) HCH (e) Total DDT <0.005 <0.005 mg/litre (wet) (c) PCB'S <0.006 0.008 mg/litre (wet) (d) Dieldrin <0.01 <0.001 mg/litre (wet) Organosilicons Nil Nil Annex II subs lances Arsenic 13 16 mg/kg dry solids Lead 990 897 mg/kg dry solids Copper 570 921 mg/kg dry solids Nickel 70 130 mg/kg dry solids Zinc 1,370 3,800 mg/kg dry solids Chromium 200 450 mg/kg dry solids
The negligible levels of the other substances listed in annex II do not warrant regular analysis.
§ Dr. Roger Thomas
asked the Minister of Agriculture, Fisheries and Food (1) how often sewage sludge dumped from ships is sampled for analysis; and on how many occasions that samples have been taken in the past years they have exceeded the permitted levels for the concentration of (a) list I substances and (b) list II substances;
(2) what is the frequency of analysis for list II substances in sewage sludge destined for sea disposal; and what have been the results of such analyses for each year since 1982;517W
(3) what is the frequency of analyses for list I substances in sewage sludge destined for sea disposal; and what have been the results of such analyses for each year since 1982.
§ Mr. Gummer
Applicants for licences for the sea disposal of sewage sludge are generally required to submit analytical data on an annual basis. Recurrent check analyses of samples of sewage sludge are carried out by officials of my Department in order to verify this data. The Oslo convention on the prevention of marine pollution by dumping from ships and aircraft recommends that analyses of sewage sludge are carried out routinely before a licence is issued in respect of those metals (except arsenic) listed in annexes I and II of the convention, and on a selective basis in the case of organochlorine compounds. These recommendations are fully met.
The Oslo convention does not specify permitted concentration levels for annex I and II substances in sewage sludges disposed of at sea.
Information on the results of analyses for annex I and II substances in sewage sludges disposed of at sea since 1982 could only he reproduced at disproportionate cost. However, summary information on the concentrations of a number of annex I and II substances present in sewage sludges licensed for sea disposal can be found in the annual reports of the Oslo commission, copies of which have been placed in the Library of the House.