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New MIRA study report: Development of environmental health indicators for Flanders

The environment in which we live influences our health. However, the link between environmental quality and health effects is a complex one. Not only the environment, but also factors such as lifestyle and genetic predisposition determine the health of individuals. Commissioned by MIRA, VITO developed for Flanders a first set of environmental health indicators for six pollutants. The study shows that many of these pollutants in our body have been decreasing over the last decade, but that the risk of health effects cannot be excluded.

Environmental indicators based on results of human biomonitoring

From measurements in humans ...

Human biomonitoring (HBM) is a method that measures internal exposure to pollutants directly inside the human body (e.g. in blood, urine, hair, etc.). The pollutants may originate from various sources and enter the body through different routes (including contaminated air or food). Over the last few years (2002-2015), three HBM campaigns were conducted in Flanders as part of the activities of the Flemish Center of Expertise on Environment and Health: FLEHS or Flemish Environment and Health Study I-III.

to a first set of environmental indicators for Flanders

In this study report, an attempt was made to use information on exposure to pollutants (the Flemish HBM results) for the assessment of health risks. To this end, the biomonitoring data were compared with health based benchmarks (HBBs). Based on literature research, quality criteria and expert surveys, six pollutants were selected from the available Flemish biomonitoring data and converted into indicators.

What are the results?

Concentration in the human body of 4 of the 6 selected pollutants is decreasing

Both for the selected heavy metals (lead, cadmium and arsenic) and for the persistent organic substances (PCBs, HCBs and PFOA) the concentration in the human body decreased in two out of three cases. Average lead and cadmium concentrations have declined over the last decade (see figure for cadmium). Lead values in newborns have even halved. Concentrations of persistent organic substances in the human body, such as PCBs in adolescents and HCBs in adults, have also decreased over the last decade. For arsenic and perfluorooctanoic acid, by contrast, no clear decrease has been observed (yet).

Health effects cannot be excluded

Despite a decrease in exposure for four of the selected pollutants, health effects cannot be excluded for any of these substances. For the majority of the examined participants, for example, a possible risk of effects on intelligence (as a result of lead) and on kidneys (as a result of cadmium, see orange and blue-orange hatched bars in figure) was established. Effects on birth weight and (pubertal) development (PFOA) and cancer effects (HCB) cannot be excluded for a percentage of examined participants. In the case of PCBs, no effects on neurological and motor development are likely to be expected for the majority of the examined adolescents. At population level, lifelong exposure to current arsenic values poses an extra risk of developing cancer (lung/bladder/skin cancer).

Uncertainty about health risks: minimal exposure is always better

The assessment of health risks is not straightforward. Scientific bodies sometimes use different health based benchmarks (HBBs). The difference between the lowest and the highest health based benchmark illustrates this uncertainty (the blue-orange hatched bars in the figure show this for cadmium). Furthermore, the information for the deduction of reliable HBBs is not always available. For PFOA, for example, research into the health effects is still under development, and for HCB better health based benchmarks are needed to assess the effect on cancer. For lead there is no safe value where exposure is not associated with effects on intelligence. It is therefore preferable to keep exposure to pollutants as low as possible.

How to avoid exposure and health effects?

Preventive measures, mainly in hotspot areas

To limit exposure, and therefore the risk of health effects, preventive measures in hotspot areas such as the Northern Campines (heavy metals) remain recommended. Information and tips on how to enjoy your vegetable garden in a safe and healthy manner are available via the campaign http://www.gezonduiteigengrond.be). Tips on healthy building and renovation are available at www.lne.be/bouw-gezond.

Attention for sensitive groups

Some subgroups in the population are more sensitive to exposure to pollutants than others. Children, for example, more often put their hands in their mouth and thus have a higher risk of lead exposure by swallowing dust or soil particles. Other sensitive groups are infants, babies, women of child-bearing age, sick and elderly people. Specific attention is paid to socio-economically more vulnerable target groups.

Further follow-up and study needed for policy underpinning

Follow-up of the time trends is crucial to evaluate how the exposure to pollutants evolves, and whether pollutants such as arsenic and PFOA decrease in humans. In addition, a broader discussion with experts and policymakers on the health based benchmarks to be used and acceptable health risks is needed. The fourth Flemish human biomonitoring programme runs from 2016 to 2020 and, in addition to monitoring time trends, focuses on new substances in the environment (www.milieu-en-gezondheid.be).

Figure: Evolution of cadmium exposure in Flemish adolescents, and interpretation based on effects on the kidneys
(FLEHS I-III, 2002-2015)

Figure Evolution of cadmium exposure in Flemish adolescents, and interpretation based on effects on the kidneys

o Read the full report ‘Development of environmental health indicators based on Human Biomonitoring results in Flanders’ (PDF, 3 MB) (Dutch report with English summary)

o MIRA indicator Lood in navelstrengbloed van pasgeborenen

o MIRA indicator Cadmium in bloed van jongeren

o MIRA indicator Arseen in urine van jongeren

o MIRA indicator Polychloorbifenylen in serum van jongeren

o MIRA indicator Hexachloorbenzeen in serum van volwassenen

o MIRA indicator Perfluoroctaanzuur in navelstrengserum van pasgeborenen

o MIRA indicators Milieu, Mens en Gezondheid

o More info at: Flemish Center of Expertise on Environment and Health

o MIRA contact: Floor Vandevenne (f.vandevenne@vmm.be)