§ Mr. Canavanasked the Secretary of State for the Environment if he will list those areas of Britain having the ten highest and the ten lowest background soil levels of polychlorinated biphenyls and 2,3,7,8 tetrachlorodibenzodioxin.
§ Mrs. RumboldI am not aware of any comprehensive survey of soil levels of PCBs or of 2,3,7,8 tetrachlorodibenzodioxin in Britain. Hence there is no satisfactory basis on which to single out the ten highest and the ten lowest concentrations of these chemicals in soil.
§ Mr. Canavanasked the Secretary of State for the Environment which agencies are responsible for setting permitted levels for human exposure to polychlorinated biphenyls, polychlorinated dibenzodioxins and polychlorinated dibenzofurans in milk, fat, soil and drinking water and with what frequency these levels are reviewed.
§ Mrs. RumboldThe Agriculture and Health Departments are responsible for coordinating the monitoring of levels of contaminants in food, including milk and animal fat. There are no specified maximum permitted levels for polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (PCDDs) or polychlorinated dibenzofurans (PCDFs) in foodstuffs.
Permitted levels of these substances in soil are not set in the United Kingdom. The interdepartmental committee on the redevelopment of contaminated land advises on the problems of redeveloping contaminated sites generally.
A maximum allowable concentration for PCBs in drinking water (0.1 microgram per litre) is set by the EEC Directive 80/778/EEC which came into force in July this year. The Department of the Environment is responsible for implementing this directive in the United Kingdom but any review of the levels set by the Directive is a matter for the European Commission. There are no specified maximum allowable levels for PCDDs or PCDFs in drinking water.
§ Mr. Canavanasked the Secretary of State for the Environment if he will list those districts in which domestic refuse incinerators have been tested for the polychlorinated biphenyls, dioxin and furan content of flue gases; what was the temperature of combustion in each case; on which dates or with what frequency the tests have been made; and what were the concentrations and isomers of any polychlorinated dibenzodioxins or polychlorinated dibenzofurans detected.
§ Mrs. RumboldA programme of investigation is currently under way, based on analysis of stack emissions, initially from municipal waste incinerators located in Gateshead, Bristol, Coventry, Wolverhampton and Sheffield. When the investigation has been completed and the results assessed, a report will be published. It is expected that this will be in the latter half of 1986. In addition, tests have been carried out on the Edmonton incinerator on behalf of the Greater London council.
§ Mr. Canavanasked the Secretary of State for the Environment what recommendations he issues as to the technical detail of incinerators for the incineration of polychlorinated biphenyls and other toxic waste.
§ Mrs. RumboldGeneral advice on the appropriate conditions for incineration of "PCB" wastes has been 95W given in DOE Waste Management Paper No. 6. Technical advice is also available from Her Majesty's Industrial Air Pollution Inspectorate of the Health and Safety Executive.
§ Mr. Canavanasked the Secretary of State for the Environment if flue gases from combustion plants and industrial premises other than municipal refuse incinerators have been tested for polychlorinated dibenzodioxins, polychlorinated biphenyls and polychlorinated dibenzofurans content.
§ Mrs. RumboldHer Majesty's Industrial Air Pollution Inspectorate has carried out a number of such tests at registered chemical incineration works. Tests have also been carried out at various other installations.
§ Mr. Canavanasked the Secretary of State for the Environment what procedures exist for the regular or continuous monitoring of the polychlorinated biphenyl, polychlorinated dibenzodioxin and polychlorinated dibenzofuran content of flue gas emissions from combustion plants, industrial premises and municipal refuse incinerators; and if he plans any changes in these arrangements.
§ Mrs. RumboldSpot sampling is carried out by Her Majesty's Industrial Air Pollution Inspectorate in addition to monitoring checks by the operators themselves. Research to establish continuous monitoring techniques for emissions from chemical incineration works has been commissioned from the Harwell laboratory. Research to develop sampling techniques for application to municipal waste incinerators has been commissioned from the Warren Spring laboratory.
§ Mr. Canavanasked the Secretary of State for the Environment if he will list, for all those United Kingdom incinerators licensed to burn polychlorinated biphenyls, the maximum sustainable temperature for each incinerator.
§ Mrs. RumboldThere are three commercially available high-temperature incinerators licensed to burn polychlorinated biphenyls in the United Kingdom. Only two are currently being operated for the combustion of PCBs. The temperature of each incinerator varies according to its construction materials and operating practices. The maximum refractory temperature is about 1200°C with flame temperature several hundred degrees higher. Information of the kind sought is not centrally available for the various "in-house" facilities licensed to burn waste of this type.
§ Mr. Canavanasked the Secretary of State for the Environment what information he has as to the maximum daily throughput of each United Kingdom incinerator licensed to burn polychlorinated biphenyls.
§ Mrs. RumboldNone. It would be for waste disposal authorities in the first instance to consider whether there should be any such limit in the terms of the licence issued by them. However, control over gaseous emissions from such premises is a matter for Her Majesty's Industrial Air Pollution Inspectorate.
§ Mr. Canavanasked the Secretary of State for the Environment what was the total tonnage of polychlorinated biphenyl materials imported into the United Kingdom for destruction during each of the past 10 years; and what proportion of the total was incinerated at each licensed site.
96W
§ Mrs. RumboldThis information can only be provided at disproportionate cost.
§ Mr. Canavanasked the Secretary of State for the Environment what he estimates will be the total tonnage and likely sources of polychlorinated biphenyls likely to require destruction in the United Kingdom during each of the next 10 years.
§ Mrs. RumboldIt is impossible to estimate reliably on an annual basis over the next 10 years the total tonnage of polychlorinated biphenyls likely to require destruction in the United Kingdom. However the sources of PCBs are likely in the main to be redundant electrical transformers and capacitors.
§ Mr. Canavanasked the Secretary of State for the Environment what is the current position regarding the import into the United Kingdom of polychlorinated biphenyl materials for incineration; and if he will list the countries of origin and the quantities of such material.
§ Mrs. RumboldThe Department are not aware of any imports of polychlorinated biphenyl materials for incineration in the United Kingdom within the last six months.
§ Mr. Canavanasked the Secretary of State for the Environment if he will list, by tonnes of material per six month period, the quantity of hazardous wastes incinerated at registered plants in the United Kingdom between January 1980 and June 1985.
§ Mrs. RumboldInformation in the form requested is not available.
§ Mr. Canavanasked the Secretary of State for the Environment what steps he has taken to satisfy himself that the existing code of practice for polychlorinated biphenyl disposal, as outlined in section 8 of Waste Management Paper No. 6, provides for adequate furnace residence times and temperatures to guarantee the complete destruction of polychlorinated biphenyls.
§ Mrs. RumboldTrials supervised by Her Majesty's industrial Air Pollution Inspectorate have been carried out since the publication of Waste Management Paper No. 6 on all commercially available high-temperature incineration plants in the United Kingdom. These plants have demonstrated a destruction efficiency of more than 99.999 per cent., and polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzon-furans (PCDFs) in the emissions have been consistently below the analytical limit of detection.
§ Mr. Canavanasked the Secretary of State for the Environment whether he will make a statement about the progress of current research to assess background levels of dioxins, furans and polychlorinated biphenyls in soil and groundwater; and what plans he has to extend the existing database.
§ Mrs. RumboldThe accurate analysis of polychlorinated dibenzodioxin (PCDDs) and polychlorinated dibenzofuran (PCDF) levels in soil is a difficult and costly procedure. My Department is currently supporting research work to refine the analytical procedure for the extraction, separation and subsequent quantitative determination of these chemicals in soil. Once this has been achieved, soil samples will be analysed from various sites selected to establish the range of background levels 97W in the United Kingdom. There are no plans to measure background levels of PCDDs or PCDFs in groundwater. In view of the extremely low solubility of these chemicals in water, significant contamination is unlikely and this is not considered an appropriate medium to monitor.