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An assessment of the milk,
soil and vegetation samples
taken in the vicinity of the
Hanson Cement plant
between 2004 and 2009
Introduction
In April 2010, Mrs Edwina Hart AM MBE, the then Minister for Health and Social Services,
requested that Public Health Wales work with other interested parties and the local
community to gain a better understanding of the health concerns associated with Hanson
Cement (formerly Castle Cement). An investigation response team has been established to
provide expert advice and support in response to the health concerns. This report forms one
part of the overall response in relation to concerns over dioxins and heavy metals in the
food chain as a result of the operation of the Hanson Cement plant.
Aim
There are many sources of dioxins and heavy metals in the environment and the
information available does not allow the distinction between those generated by the
Hanson Cement plant and those present from other sources. This report, therefore, aims to
assess the implications (where possible) of available sample results for dioxins, dioxin-like
PCBs and heavy metals from all sources on locally produced food and local consumers.
The report also aims to address specific concerns raised by the local community as part of
the investigation response.
Sample sources
Hanson Cement were required, as part of the kiln 4 pre-operating conditions issued by the
Environment Agency (EA) (permit issued in the name of Castle Cement), to undertake soil,
vegetation and milk monitoring to assess the levels of dioxins / furans, dioxin-like PCBs and
heavy metals contamination in the vicinity of the site. This monitoring has continued by
agreement since.
In 2004, samples were taken from a number of locations in and around the local
community. Following a baseline survey in 2005, it was agreed with the EA that samples
would be collected from Dyke farm, which has land surrounding the site. A summary of the
available samples is included in Table 1. The list of samples, locations and results is available
at Annexe 1.
2004* 2005
2006
2007 2008**
Soil metals
Y
Y
Y
Y
Soil dioxins
Y
Y
Y
Y
Vegetation metals
Y
Y
Y
Y
Vegetation
dioxins
Y
Y
Y
Milk metals
Y
Y
Y
Milk dioxins
Y
Y
Y
Table 1 – summary of sample results included in assessment
2009
2010***
Y
Y
Y
Y
* A 2004 milk sample was previously discounted by the Food Standards Agency due to flaws
in the analysis1. This result has not been included in the assessment.
**One soil sample was also taken from a Penyffordd residential property by Hanson Cement
in 2008 following a complaint and this has been included.
***The 2010 results were not available for inclusion in the assessment at the time of
preparation.
Relevant food safety legislation and limits
General Food Law (Commission Regulation (EC) No 178/2002) lays down the general
principles and requirements of food law and procedures in the matter of food safety. Its
provisions are enforced in the UK by the General Food Regulations 2004 (as amended).
Article 14 of (EC) 178/2002 sets out that food shall not be placed on the market if it is
unsafe. Food is deemed to be unsafe if it is considered to be:
 injurious to health; or,
 unfit for human consumption
The article also indicates what factors need to be taken into account when determining
whether food is injurious to health or unfit.
Commission Regulation (EC) No. 1881/2006 (as amended) sets maximum levels for certain
contaminants in foodstuffs. Article 1 states that the foodstuffs listed in the regulation shall
not be placed on the market where they contain a listed contaminant exceeding the
maximum level set out in the annexe. The relevant limits for contaminants in milk are In
Table 2.
1
http://www.wales.nhs.uk/sites3/Documents/271/Castle%20Cement%20Advice%20Statement.pdf
Contaminant
Limit
Dioxins (WHO-PCDD/F-TEQ)
3.0 picogram(pg)/g fat
Dioxins and dioxin-like PCBs (WHO-PCDD/F-PCB-TEQ) 6.0 pg/g fat
Lead
0.02 mg/kg wet weight
Table 2 – maximum levels for contaminants in milk set in Regulation (EC) 1881/2006 (as
amended)
WHO-TEQ
Dioxins and dioxin-like PCBs are chemicals with different degrees of dioxin-like toxicity. The
use of Toxic Equivalency Factors (TEFs) allows concentrations of the less potent compounds
to be expressed as an overall equivalent concentration of the most toxic dioxin, 2,3,7,8TCDD. These potency-weighted concentrations are then summed to give a single value
expressed as a Toxic Equivalent (TEQ). The system of TEFs used in the UK and a number of
other countries is that set by the World Health Organisation (WHO), and the resulting
overall concentrations are referred to as WHO-TEQs.
It is important to understand that limits are not safety limits. Although it would be unlawful
for a food business to sell food exceeding a relevant limit, consuming a portion of food that
does exceed a limit does not necessarily imply a risk to health.
More information on food safety legislation (including full texts) is available at;
http://www.food.gov.uk/foodindustry/regulation/foodlaw/foodlawguide/
Action levels
In addition to the maximum levels for dioxins set in Regulation (EC) 1881/2006 (as
amended), the UK also uses a lower action level above which investigative action may be
undertaken to identify and mitigate the source of dioxins. The action level for raw milk is
2pg WHO-TEQ/g fat.
Tolerable Daily Intake
A Tolerable Daily Intake (TDI) is the amount of a substance that can be ingested daily over a
lifetime without appreciable health risk. It is expressed in relation to the bodyweight (bw) in
order to allow for different body size, such as for children of different ages. A daily intake of
1 pg/kg bw/day is 60 pg for an average 60 kg person.
These values are used alongside maximum limits and normal dietary exposure when
assessing the risk from certain contaminants such as dioxins. Occasionally consuming more
than the TDI would not be expected to result in harmful effects, providing that the average
intake over a prolonged period is within the TDI.
The UK Committee on Toxicity (COT) set a tolerable daily intake (TDI) of 2pg WHO-TEQ/kg
bw per day for dioxins and dioxin-like PCBs in 2001. This was reaffirmed by the COT in 2007.
Upper bound high level dietary intakes of dioxins and dioxin-like PCBs in 2001 for adults in
the UK were estimated to be 1.4 pg WHO-TEQ/kg bw/day.
More information is available here;
http://cot.food.gov.uk/cotstatements/cotstatementsyrs/cotstatements2007/cot200702
Tolerable Weekly Intake
Tolerable weekly intakes are similar to TDIs in that they give a measure of the amount of
substance that can be ingested weekly over a lifetime without any appreciable health risk.
The European Food Safety Authority and the joint WHO/FAO expert committee for food
additives (JECFA) have set provisional maximum tolerable daily and weekly intakes (PMTDI
and PTWI) for certain heavy metals and these levels are used alongside maximum limits and
normal dietary exposure (assessed using total diet studies - see Table 3) when assessing the
risk from heavy metals. As above, occasionally consuming more than the PTWI would not be
expected to result in harmful effects, providing that the average intake over a prolonged
period is within the PTWI.
Element
Limit used
Value
Aluminium
PTWI
1mg/kg body weight
Cadmium
EFSA TWI
2.5microgram (ug)/kg bw
Copper
PMTDI
500ug/kg bw
Mercury
PTWI
5ug/kg bw
Nickel
WHO TDI
5ug/kg bw
Zinc
PMTDI
1mg/kg bw
Table 3 – limits used in evaluating exposure to certain metals in the diet
ALARP
Certain heavy metals and metalloids, such as lead and arsenic, have no relevant tolerable
intakes or reference doses by which to assess their safety in the diet. Due to their harmful
properties, and the uncertainty as to threshold levels for those harmful effects, exposure
should be as low as reasonably practical (ALARP).
Dietary exposure studies
Dietary exposure to dioxins and PCBs in a variety of foods purchased at retail throughout
the UK was studied in 2007 by the Food Standards Agency. The study found no samples
exceeding regulatory limits and there were no concerns for human health. The full results
are available here:
http://www.food.gov.uk/multimedia/pdfs/fsis0407.pdf
Dietary exposure to metals and other elements was estimated by the Agency using the
results of the 2006 total diet study and evaluated by the Committee on Toxicity. The COT
evaluated the results of this survey and did not identify specific concerns for the health of
consumers, but noted a need for more information on aluminium and barium. The COT also
stressed that efforts should continue to reduce dietary exposure to inorganic arsenic and to
lead. The full results are available here:
http://www.food.gov.uk/multimedia/pdfs/fsis0109metals.pdf
The Agency has also completed a survey of heavy metals and other elements in allotment
produce to determine concentrations of metals and other elements in fruits and vegetables
from allotments in a variety of environments. Estimated dietary exposures to the elements
measured in the survey did not pose a risk to consumer safety. The full results are available
here:
http://www.food.gov.uk/science/surveillance/fsisbranch2006/fsis0106
Description of results
Milk
Milk samples are taken from the bulk tank at Dyke farm. The most recent samples were in
2009 and gave results of 0.70nanogram (ng)/kg WHO-TEQ, below the regulatory limit of
3ng/kg and the action limit of 2ng/kg. This is lower than results in previous years. The
highest recorded result was 1.85ng/kg in 2006. No results have exceeded the regulatory
limit or action level.
The results for heavy metals have been below the limit of detection for each analysis.
Soil
The 2006 results for dioxins were within the range 0.2 – 17.0ng/kg WHO-TEQ, within
expected parameters for soils in rural areas and similar to the levels in 2005. There was little
change in the heavy metal concentration except for an increase in zinc and a decrease in
manganese levels.
Samples were also taken from a Penyffordd residential property in 2008. The results were
22ng/kg WHO-TEQ for dioxins. Though this result is high, it is not outside the range of
results expected from soils in rural Wales. The UK soil and herbage study conducted by the
EA2 found levels in soils from rural Wales up to 27ng/kg.
Vegetation
Dioxin results for vegetation peaked during 2006 at 0.10-0.11ng/kg WHO-TEQ and have
decreased since to between 0.02 and 0.03ng/kg WHO-TEQ. PCB results have remained at
<0.03ng/kg WHO-TEQ on each sample. The concentrations of certain metals such as arsenic
and lead have decreased between 2005 and 2009, whilst others such as copper and mercury
have not changed.
Assessment of exposure to dioxins from milk
The following assessment is based on the highest dioxin result for milk from the Dyke farm
bulk tank (1.85ng/kg fat weight) and assumes that a person’s entire milk supply comes from
this one farm. It should be noted that;
 The results for 2007 and 2009 are below 1ng/kg
 Only the residents at Dyke farm consume their entire supply from this location.
Consumers in the area purchase milk that has come from dairies. The upper bound
concentration of dioxins in UK retail cows milk is 0.34ng/kg +/- 0.09ng/kg3
 None of the results have been above the regulatory maximum limit or the action
level
2
http://www.doeni.gov.uk/niea/txt/index/index/uk_soil_herbage_pollutant_survey_report10.pdf
3
http://www.food.gov.uk/multimedia/pdfs/fsis0407.pdf
Assuming full fat milk is 4% fat (UK whole milk is normally 3.5), the dioxin concentration in
whole milk is 0.074 pg of dioxins (WHO-TEQ) for every gram of milk (calculation below).
1.85ng/kg*4/100 = 0.074ng/kg milk or 0.074pg/g milk (WHO-TEQ)
Consumption figures for milk from the National Diet and Nutrition Survey4 for high level
(97.5%) consumers are:
Adults
Young persons (4-18 years old)
8.73 g of milk per kilogram of body weight per day
22.01 g/kg bw/d
The consumption figures for young persons show a highly skewed distribution with a mean
value of 6.58 g/kg bw/d. For adults the mean was 2.96 g/kg bw/d.
We have excluded infants from our estimate as the consumption figures predate the advice
against consumption of cows milk below 1 year of age and the figures for milk intake also
include breast milk and formula. We have also excluded toddlers (1.5 – 4.5 years old)
because Agency advice is that children should not drink raw milk due to the potential
presence of pathogens.
Assuming entire consumption is of full fat milk (4%) at the highest reported value for a high
level consumer, the estimate exposure to dioxins is;
Adults
Young persons
0.64 pg WHO-TEQ/kg bw/d
1.63 pg WHO-TEQ/kg bw/d
Based on the estimated dioxins exposure at the reported highest value for dioxins, an adult
high level consumer of milk would not have an exposure at the TDI even when combined
with upper bound high level dietary intakes of dioxins and dioxin-like PCBs from the rest of
the diet.
For a young high level consumer, exposure from milk alone at the highest measured level
would be below the TDI although it would be greater than this when combined with upper
bound high level dietary intakes of dioxins and dioxin-like PCBs from the rest of the diet.
However, given the skewed distribution of milk intake, the variation in measured dioxin
levels and the conservative nature of combining two upper level exposures, this is unlikely
to be a significant risk.
4
http://tna.europarchive.org/20110116113217/http://www.food.gov.uk/science/dietarysurveys/ndnsdocuments/
In order to reach the TDI based on dioxin levels of 1.85ng WHO-TEQ/kg a young person
would need to consume between 540 and 1080ml of full fat milk directly from Dyke farm
every day. Likewise, an adult would need to consume between 1620 and 1890ml every day.
For context, DEFRA estimated average liquid milk consumption in the UK at around 1.6 litres
per person per week for 2007.
Assessment of exposure to heavy metals from milk
The concentrations of metals other than copper, zinc and manganese in the samples were
below the limits of detection, so are not a cause for concern. The levels of copper, zinc and
manganese are comparable to the levels reported in milk in the UK Total Diet Studies (used
to estimate the general UK population’s exposure to contaminants) and are not a cause for
concern.
Assessment of potential exposure to dioxins from soil
The dioxin results for some of the soil samples taken at Dyke farm are high but do not raise
any concerns for the local food chain.
The result for the Penyffordd property is high; however, this cannot be attributed to Hanson
cement alone as there may be other sources of dioxins in the vicinity (such a level is likely to
be from historical activities and the proximity to a road would contribute some component
attributable to exhaust fumes). It is unlikely that this would have a significant impact on
dioxin levels in the majority of edible crops because uptake of dioxins into plants via their
roots is generally negligible. Washing and peeling would remove the vast majority of surface
contamination from the soil.
Research has indicated that plants from the cucurbitaceous family, including courgettes and
pumpkin, may be an exception to the rule that uptake of dioxins by plants via their roots is
negligible; therefore, as a precaution, the resident was advised not to grow these
vegetables. The resident was also advised not to keep free range chickens for their eggs as a
precautionary measure as the uptake of dioxins from soil ingested by hens into their eggs is
very efficient.
Assessment of potential exposure to metals from soil
The results for the samples taken at Dyke farm and the residential property for 2008 are
comparable with the levels found in soil during the 2006 allotment survey; therefore, they
do not pose a risk to consumer safety. Standard Agency advice for consumers of allotment
produce is to thoroughly wash and peel before consumption and to ensure a varied diet
from a variety of sources. This advice is also applicable here.
The 2004 results for Spon Green farm did show moderately elevated levels of arsenic and
lead and a relatively high result for cadmium when compared with the results of the UK soil
and herbage pollutant survey 20075. Given the levels found, washing and peeling would be
sufficient to ensure that consumers are protected.
Assessment of vegetation results
The levels of dioxins, PCBs and heavy metals in the samples 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
It should be remembered that only a few individuals consume raw drinking milk in the
locality. The greatest source of risk from drinking raw milk is that of food poisoning. Agency
advice is that children, people who are unwell, pregnant women and older people are
particularly vulnerable to food poisoning and so should not have unpasteurised milk or
cream. The results of contaminants in the milk from Dyke farm do not pose a significant
additional risk to consumers.
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
Based on the assessment of the sample results provided to the Agency, the Agency’s
standard advice on allotment produce is sufficient to mitigate any risks to local consumers
from contaminants in the soil.
5
http://www.environmentalresearch.info/search/DatabaseSearchBin.aspx?outputid=444644&type=pdf