Hanson Cement Review of Dioxin data Professor David

Hanson Cement: Review of Dioxin data Professor David Russell Centre for Radiation, Chemicals and Environmental Hazards (Wales) The Health Protection Agency Cardiff Wales UK

Principal areas • Physico-chemical properties • Sources • Routes of exposure • Potential health effects • Findings • Conclusions

Dioxins: Physico-chemical properties • Generic term for group of 210 chemicals of similar structure. • 2 principal groups, dibenzo-furans and chlorinated dibenzo-dioxins • CDDs -75 compounds • Differ in amount of chlorine atoms present. • Most pose no threat to health at levels found in environment. • 17 are of concern • TCDD most toxic.

Physico-chemical properties (continued) • High molecular weight, solid or crystals • Low vapour pressure • Non-flammable • Odourless • Fat soluble • Environmentally and biologically stable

Sources • No commercial production • Man-made (anthropogenic) and natural sources. • Combustion and incineration processes-smelting, paper bleaching, vehicle emissions. • Cigarette smoke • Natural sources include forest fires. • Levels in the environment have declined since 1970 s.

Environmental fete and exposure • Persistent and ubiquitous • Air-molecules, particles, ash • Soil (avid binding) • Water (sediment) • Plant leaves • Exposure largely ingestion (food). • 90% through consumption of meat, dairy products and fish.

Potential health effects • Acute exposure-commonest effect is chloracne • High dose exposure-nausea, vomiting, diarrhoea and weight loss. • Neurological symptomsheadaches, generalised weakness and muscular pains. • Similar effects whether through inhalational, oral or dermal exposure.

Potential health effects-chronic • Similar to severe acute exposure. • Based on accidents, occupational and residential exposure, as well as animal studies. ØChloracne ØLiver disease ØCardio-vascular disease ØAlterations in immune and thyroid function ØCause cancer in laboratory animals. Non-genotoxic

Dioxins and Cancer • Dioxins are non-genotoxic carcinogens ie they do not directly bind to genetic material (DNA). • They display threshold characteristics. • Below the threshold, no observable adverse effect. • NOAEL-highest dose at which there is no significant increase in biological effect or frequency of effect. • LOAEL-lowest dose at which an adverse effect seen. • Based on most sensitive effect in most sensitive species. NOAEL

Regulatory Toxicology NOAEL • Based on the most sensitive health end point in the most sensitive species. • Used to define a tolerable daily intake for humans following introduction of an uncertainty factor (UF). • Typically UF is two-fold involving a consideration for both inter-and intra -species variability. • Usually of order of 100 • TDI=NOAEL/Uncertainty factor • Therefore TDI incorporates large safety factor and is conservative

Dioxins: LOAEL Approach • Female rats basis of TDI • LOAEL used to reflect body burden • Extrapolation to humans using safety factor • TDI of 2 pg/kg/day [note: 1 pg = 10 -12 g]

UK National Emissions • Significant reduction over 20 years. • Reflects more stringent regulation. • By 2008, most emissions from urban sites.

UK Emissions Total UK dioxin emissions to atmosphere 1990 -2009 (Source: NAEI)

National dioxin emissions: Manufacturing and construction sector Total UK dioxin emissions to atmosphere from combustion in manufacturing and construction sector (source: NAEI)

Regional emissions 2008 • Hanson Cement largest point source emitter in Flintshire. TT • 6 th. largest in Wales. • Contributed 1% of total emissions from “top ten” emitters in Wales. • 11% of dioxin emissions from all point sources within 15 mile radius. Total modelled emissions of dioxins on 1 km grid basis (NAEI; 2008)

Regional Point Source Emissions

Dioxin emissions from Hanson Cement • General trend of decreasing emissions. • Mirrors national trends • Notable exception of 2004. • Extrapolation of stack emissions to human exposure requires intake estimation based upon soil, herbage and dairy product concentrations and consumption. • Can then compare with TDI. Total emissions of dioxin to environment from cement works at Padeswood

Exposure to dioxins Deposition SOURCE Inhalation Ingestion Production Ingestion

Dioxins in food • Dioxins are found at low levels in all foods, including foods that are important sources of nutrients • Mainly fatty foods such as meat, fish and dairy products • Intakes are falling and have reduced by 85% since 1982

Regulatory limits • Introduced in 2001 by the EC • Formally reviewed in 2006 based on the results of monitoring and new research • Constantly under review in working groups • It is important to understand that regulatory limits are not safety limits • Consuming a portion of food that does exceed a limit does not necessarily imply a risk to health

Regulatory limits • Contained within regulation (EC) 1881/2006 (as amended) • Using milk as an example; • Dioxins = 3. 0 picogram(pg)/g fat • UK also operates action levels whereby investigations are conducted into the source of the contamination • Action level for milk is 2. 0 pg/g fat

Tolerable Daily Intake (TDI) • TDI as a means to assess risk from dioxins • 2001 assessment by the Committee on Toxicity (COT) - 2 pg/kg bw per day • 2007 reaffirmation by COT • WHO 1 – 4 pg/kg bw per day

FSA surveys • Dietary exposure to dioxins in a variety of foods purchased at retail throughout the UK was studied in 2007 • No samples exceeded existing regulatory limits. There were no concerns for human health. • Have also conducted targeted surveys at offal, infant formulae, fish, shellfish and fish oil supplements • Current exposure estimated to be 1. 4 pg WHO-TEQ/kg bw/day.

Local results • Sample results available between 2004 and 2009 – milk, soil and vegetation (moss) • 2004 samples taken from a variety of locations around the plant • 2005 – 2009 from Dyke farm • Samples taken by company and provided to EA • Cannot distinguish between sources of dioxins

Milk 3. 50 Milk samples taken from Dyke farm 3. 00 pg/g fat 2. 50 Regulatory limit 2. 00 Action level Farm sample 1. 50 UK retail milk 1. 00 0. 50 0. 00 2005 2006 2007 2008 2009

Milk • No results above regulatory limit or UK action level • UK retail milk (2006) – 0. 34 pg/g fat (+/-0. 09) • Highest result from Dyke farm (2006) – 1. 85 pg/g fat • Last result from Dyke farm (2009) – 0. 70 pg/g fat • Consumption of milk at the highest level (every day) would not result in an adult breaching the TDI even when combined with exposure from the rest of the diet 1 pg/g = 1 ng/kg = 1 g in 1, 000 tonnes

Soil • Highest result (2005) – 19 ng/kg • Last result (2006) – between 0. 2 and 17 ng/kg • 2008 residential sample – 22 ng/kg • Welsh rural soils between 0. 28 and 27. 77 ng/kg (n=33)* • Median result from survey was 1. 83 ng/kg • Comparable with UK results • Uptake of dioxins into plants via their roots is generally negligible • Washing and peeling removes the vast majority of surface contamination from the soil * - Environment Agency soil and herbage study

Soil • Standard advice issued by the Agency to all consumers of allotment produce is: • to thoroughly wash your hands after gathering • to thoroughly wash and peel all produce prior to consumption • to consume products from different sources and not to source all of your produce from the same plot

Vegetation • Highest result (2006) - 0. 10 -0. 11 ng/kg • Last result (2009) – 0. 02– 0. 03 ng/kg • The levels of dioxins appear to be very low; however, as no control data are available it is not possible to extrapolate from these samples to uptake of contaminants into vegetation.

Conclusions • Dioxins are the product of man-made and natural sources • They are by-products and have no commercial use • Dioxins are ubiquitous • National (UK) emissions of dioxins have reduced significantly over 20 years. • Emissions from Hanson Cement have fallen markedly since 2000, reflecting new kiln. • Hanson Cement largest point source emitter of dioxins in Flintshire. • Contributes 11% of point source emissions within 15 mile radius. • Greatest source of exposure likely to be through food chain

Conclusions • Dioxins are present in all foods • Intakes are falling and have reduced by 85% since 1982 • Current exposure estimated to be 1. 4 pg/kg bw per day • TDI is a key indicator for determining the risk of health impacts – 2 pg/kg bw day • Milk and soil sample results show no concerns for health • Standard advice