WHO:Eliminating environmental health hazards
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- This text is taken from the WHO report "Health and Environment in Europe: Progress Assessment", 2010, ISBN 978 92 890 4198 0. [1]
Regional priority goal IV: We commit ourselves to reducing the risk of disease and disability arising from exposure to hazardous chemicals (such as heavy metals), physical agents (e.g. excessive noise), and biological agents and to hazardous working environments during pregnancy, childhood and adolescence.[1]
Contents
Key messages
- Policies and action to limit exposure to persistent organic pollutants (POPs) and heavy metals in food, and to eliminate exposure to lead from leaded petrol have all achieved considerable success within the Region. Constant awareness is, however, needed. Moreover, there are still challenges in many countries, with a need for improved monitoring and enforcement.
- Iternational cooperation on food safety has proved efficient, as countries develop coherent standards and regulations aiming to ensure the same level of health protection for as many citizens as possible.
- There is a lack of appropriate publicly available environmental health data, especially regarding exposure to heavy metals but also regarding contamination of the food chain and the burden of foodborne disease.
- Consideration of health aspects in environmental policies for heavy metals is low in most countries and is not proportional to the risks to health which heavy metals may create.
- Environmental noise is perceived as the most common stressor: a quarter of the population in EU countries is exposed to noise levels leading to a wide range of health effects. Noise abatement policies in many Member States need to be strengthened to address health problems effectively.
- Safety in the occupational environment improved significantly in the 1990s, but in the last decade the improvement has levelled of in the eastern part of the Region.
Regional priority goal IV addresses a wider range of environmental health issues than goals I–III and is associated with diverse environmental health risks such as toxic chemicals, physical agents (e.g. harmful noise, and ionizing and ultraviolet radiation) and hazardous working environments. It focuses on policy action to reduce and prevent hazardous exposure with an emphasis on children and other age-specific sensitivity windows. Furthermore, this goal pays particular attention to child labour and advocates the elimination of its worst forms.
This chapter focuses on three areas, giving an assessment of the situation, progress and policy action regarding:
- issues related to
- food safety, including exposure to hazardous chemicals in food;
- general exposure to lead; and
- chemical safety aspects of other heavy metals;
- environmental noise;
- occupational health, in particular work-related health problems.
Consideration is paid to the health burdens, public concerns, availability of data and evidence, and potential to take targeted action to benefit health. Despite their differences they are all of special concern for children’s health for similar reasons: the particular sensitivities of children in the pre- and postnatal periods due to their rapid development; their different metabolisms and behaviour compared to adults; and their longer life expectancy, which render them more vulnerable than adults to many environment hazards.[1]
Chemical hazards
Exposure to chemical hazards
People are exposed to huge numbers of industrial and household chemicals, pesticides and metals in air, water, food and consumer products. Many of these chemicals can be hazardous to health, especially if they are used inappropriately. Children are particularly vulnerable to chemical hazards for various reasons including naïve behaviour and because their organ systems are rapidly developing. Symptoms arising from prolonged low-level chemical exposure may only appear later in life and may be chronic and irreversible. Global industrialization, urbanization and intensive agriculture, together with growing patterns of unsustainable consumption and environmental degradation, contribute to exposure to hazardous chemicals.
New chemicals are constantly synthesized for various purposes and the capacity rigorously to test the safety of all of them prior to use is very limited. The EU Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulation, introduced in June 2007, makes industry responsible for assessing and managing the risks posed by chemicals and providing appropriate safety information to their users. Adverse health outcomes are a result of many factors including the compound’s toxicity, and the exposure levels and characteristics of the exposed population. It is, however, assumed that many new chemicals will not take on public health importance.
Food safety is one of the most important factors for good health. Several serious accidental poisonings have arisen due to food contaminated by POPs or heavy metals, and long-term low-level exposure can cause chronic health effects. Furthermore, the microbiological safety of food is crucially important for public health. The surveillance of foodborne diseases and the monitoring of contamination in the food chain are, however, inadequate. Reporting of foodborne disease only represents the tip of the iceberg. A risk-based approach is needed in the management of exposure to chemical hazards. Priority should be given to assessing those chemicals with the greatest risks for public health, those that accumulate in the body and those to which chronic exposure at low levels cause adverse health outcomes.
Groups of chemicals that should be considered when assessing the safety of food are pesticide residues, veterinary drug residues, heavy metals, POPs and other organic contaminants, microbial toxins, food additives, compounds formed unintentionally during the processing of food, contaminants from packaging and storage and, last but not least, the major constituents of food itself, such as excess salt, sugar and fat. The inherent toxicity of a substance does not necessarily indicate high public health concern, as population exposure and vulnerability are also important determinants.[1]
Persistent organic pollutants
POPs have been recognized as a serious concern since the 1960s and 1970s, when dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) were banned or phased out in many industrialized countries. Over time, it became clear that this was not sufficient. Besides staying in the environment for long periods, POPs are prone to accumulate in higher organisms and to magnify in the food chain: levels increase by several orders of magnitude from sea plankton up the food chain to people. Owing to their semi-volatility and persistence, some are transported through air and water to locations where they have never been used, such as the Arctic. At high concentrations, POPs cause reproductive and developmental effects in wild and laboratory animals. There is more uncertainty about health effects in humans at typical levels of exposure, which can be lower than in some other species.
Among the POPs, polychlorinated dioxins (PCDDs) and dioxin-like chemicals (including polychlorinated dibenzofurans (PCDFs) and dioxin-like PCBs) appear to have the lowest safety margin and to be the most likely group to cause adverse effects in humans. During the 1970s, at concentrations 5–10 times higher than at present, they were possibly the cause of subtle effects such as effects on tooth development. The sources of these compounds were the incineration of municipal waste, chlorine gas bleaching of wood pulp and the metal industries, together with a number of minor sources. Until the 1980s, there were also important impurities in the production of certain chemicals (PCBs, chlorophenols and their derivatives). Advances in abatement have been greatest in areas such as waste incineration and the pulp and paper industry, resulting in the reduction of POP concentrations in environmental samples, including lake- and seabed sediment layers, fish, fish-eating birds and seals. The largest remaining sources are the metal and cement industries, landfill fires and small-scale wood and biomass burning. There may still be considerable variations among countries.
There is evidence that developmental effects occur even at the lowest measured POP concentrations. Dioxin levels in human milk provide a long-term average of the body burden because these persistent compounds accumulate in breast tissue. They are relevant both as an indicator of risk during pregnancy and for measuring the chemical intake by the breastfed baby. Both of these steps are believed to be crucial for assessing the risk of developmental effects for the whole population. The most systematic information on POPs in humans is based on four rounds of human milk analysis studies of dioxins and PCBs coordinated by WHO. Dioxin levels in human milk have decreased in all countries monitored since 1988. Several European countries with higher initial levels have made particularly dramatic and important reductions. In spite of the decrease, the margin between currently prevalent and known toxic levels is still narrow enough to be of concern.[1]
WHO recognizes this concern. Nevertheless, the net beneficial effect of breastfeeding as the optimal food source for newborn babies should always be emphasized, especially when sharing information with the general public.
The body burden is clearly age-dependent and is lowest in younger age groups. For older populations with higher body burdens, the relative risk of cancer, while real, is not very high even at the highest industrial exposures. Recent results of studies on families of fishermen indicated that, despite much higher dioxin and PCB body burdens, mortality (including cancer mortality) was lower than in the general population, possibly due to the other, beneficial effects of consuming fish. In Seveso, Italy, after a very high level of accidental exposure, there were reports of developmental effects on teeth, altered sex ratios and a possible increase in some rare types of cancer.
It is more difficult to assess the health risks of compounds other than dioxins, as the data on both exposures and effects are less systematic. Organochlorine pesticides or their metabolites can still be found in human samples in Europe, but the concentrations are low and their health relevance has clearly decreased. Some compounds have more recently come into focus. Polybrominated diphenyl ethers (PBDEs – flame retardants used in plastics and textiles) were found in human milk at the end of 1990s. Certain brominated diphenylethers, such as tetra- to octa-congeners, are absorbed by different animal species and bioaccumulate to some extent. They were therefore banned by the European Commission in 2004 and their concentrations in Europe are now decreasing. Even so, continued monitoring is warranted because there is uncertainty about the metabolic fate of decabromodiphenyl ether (BDE-209), which is still in production. It is itself very poorly absorbed by biota and fairly rapidly eliminated in humans, but it may be broken down into more toxic forms.
Another new group of halogenated compounds is perfluorinated alkyl compounds (PFAs), such as perfluorooctane sulfonate, which were introduced as water repellents and for many other uses. They are also highly persistent and have been shown to accumulate in animals. Some of these compounds have, therefore, been voluntarily phased out by industry but are worth monitoring because of their persistence.[1]
Heavy metals
Heavy metals remain of particular concern, despite being a priority for regulatory measures for decades. This section focuses on lead, mercury, cadmium and arsenic, for which the evidence on hazardous properties and population exposures is the most reliable. These four metals differ in their sources and the potential outcomes of exposure.
Main sources, potential health problems from exposure and provisional tolerable weekly intake for arsenic, lead, methylmercury and cadmium
| Main sources | Primarly health concerns | Provisional tolerable weekly intake (mg/kg body weight) | |
| Arsebic | Contaminated food/water, some paints | Neurological and developmental disorders | 0.015 |
| Lead | Air, water, fuels, marine life | Neurodevelopmental and neurological disorders; organ damage | 0.025 |
| Mehtyl mercury | Fish/seafood | Neurological and developmental disorders | 0.0016 |
| Cadmium | Contaminated food | Kidney damage, low birth weight, spontaneous abortion | 0.007 |
Average intake levels of lead, mercury, cadmium and arsenic in the adult diet in 13 European countries in the early 2000s are available from the EU scientific cooperation assessment of dietary exposure. In most countries, adult intake levels were typically 10–30% of provisional tolerable weekly intake (PTWI), but sometimes higher. Data on intake by children are patchy: total intake seems to be lower than in adults, but intake per unit of body weight is higher.
Monitoring of chemical contaminants in food through total diet studies is an established practice in the Czech Republic. The observed amount of all metals in the total diet of the general population between 1994 and 2007 was far below the PTWI values. However, young children tend to eat different types of food, and different amounts per unit of body weight, so these results are not directly applicable to children under three years of age who are particularly vulnerable to the neurotoxic effects of chemicals.
The organic form of mercury, methylmercury, appears to be of greatest concern for children notwithstanding the significant limitations of information on children’s exposure to heavy metals in food. Methylmercury is highly toxic, particularly to the nervous system; the developing brain is known to be particularly sensitive. Owing to the transport of mercury through the environment and its bioaccumulation, the main source of exposure to methylmercury in the general population is diet, in particular through the consumption of fish, particularly via certain species. It is assumed that all of the mercury in fish is present as methylmercury. Toxicity has been demonstrated at low exposure levels, but fish can also be an important component of a healthy diet. It is, therefore, essential that clear guidelines for optimal fish consumption levels are widely publicized. Food sources other than fish and seafood products may contain inorganic mercury, which is considerably less toxic than methylmercury.[1]
The estimated intakes of methylmercury in Europe vary by country and region, depending on the contamination level and the amount and type of fish consumed. Some population groups may frequently consume large predatory fish (such as swordfish, tuna and pike), which are at the top of the food chain and often have a higher concentration of methylmercury. A recent EU assessment suggested that as many as 1 in 20 people may be affected. The study estimated that 1–5% of the general population in Europe (3 to 15 million people) are over the limit that the EU uses. Even more worrying is the fact that a proportion of this population, notably Mediterranean fishing communities, have levels ten times as high as the recommended norm.
The potential negative effects on health from consuming contaminated food can be greatly reduced by improving the production, processing and handling of food, educating people to limit the intake of high-risk foods and, as a priority for a longer time span, reducing environmental pollution. Lead is one of the most dangerous chemicals to children. The most important effect of long-term exposure is neurotoxicity, particularly during the first two to three years of life when early development of the central nervous system occurs. Exposure to lead during this time increases the risk of mild mental retardation, attention deficit hyperactivity disorder and other developmental disabilities. An elevated blood lead level (10 μg/dl or above) has been associated with toxicity in the developing brain and nervous system of young children, leading to a lower intelligence quotient. More recent evidence indicates that similar effects may occur below 10 μg/dl and that preventive activities should therefore aim to bring down the amount of lead in the blood to the lowest possible levels. Lead in the environment has multiple sources, including the combustion of leaded petrol, industrial processes, paint, solder in canned foods and water pipes. Exposure to lead occurs through a number of pathways (such as air, household dust, road dirt, soil, water and food). Evaluation of the relative contribution of the different sources is complex and is likely to differ between areas and population groups.
Exposure to lead in Europe has clearly decreased in the last 20 years following the elimination of tetraethyl lead as an anti-knock additive in petrol in many countries. Generally, lead in blood levels began to decline earlier in western European and Scandinavian countries than in eastern Europe, largely due to the earlier introduction of unleaded petrol. Emission trends from 24 European countries have shown that total emissions of lead dropped by 90% from 1990 to 2003 (22). In the mid-1980s, a collaborative study between WHO and the European Commission found levels of lead in children’s blood of 18.2–18.9 μg/dl in Bulgaria, Hungary and Romania compared to 11.0 μg/dl in Italy and 7.4 μg/dl in Germany. This difference was still evident in the 1990s, with considerably lower levels in France, Germany, Israel and Sweden compared to Hungary and the Russian Federation.
The benefits of switching completely to unleaded petrol are further illustrated by a series of blood lead measurements in 3700 children living in urban Sweden. A dramatic decline was observed between 1978 and 2005, with the first decrease in the early 1980s when unleaded fuel was introduced. Residual exposure to re-suspended lead disappeared only after the complete elimination of leaded petrol from the market in 1994.
Although many countries have applied systematic interventions to phase out industrial sources of lead emissions, leaded petrol still exists in some countries in the east of the Region. For example, it will not be completely phased out in Montenegro and Serbia until 2015. Furthermore, measurements of blood lead levels in children living near hot-spots show that plumbing and local industries continue to be important sources of concern in some countries (e.g. Bulgaria, Poland, Russian Federation, The former Yugoslav Republic of Macedonia, Ukraine). Although lead levels in people show a decrease in all these countries, it is difficult to assess progress owing to a lack of systematic human bio-monitoring. Regular population-based surveys of lead in blood, and monitoring of other chemicals of concern, using uniform protocols specific to various age groups, would greatly enhance the ability to assess exposure and trends as well as the potential health impacts and effectiveness of policy measures.[1]
Microbial contamination of food
Although a strong theme in this chapter is chemical contamination of food, it is essential that exposure to hazardous microbiological agents in food should not be overlooked. Foodborne disease caused by microbes, both sporadic cases and outbreaks, is very common throughout the Region, even in countries with high hygiene standards. The most common clinical presentation of microbiological foodborne diseases takes the form of gastrointestinal symptoms, but such diseases can also lead to chronic symptoms including arthritis, neurological or immunological disorders and cancer as well as septicaemia, multi-organ failure and death. Foodborne outbreaks are about an order of magnitude commoner than waterborne episodes, although fewer people are typically involved in each foodborne outbreak.
The global burden of foodborne diseases and its impact on development and trade are currently unknown. Data are sparse and only cover people who have sought medical care and who have received an accurate diagnosis, provided the reporting system is operational and efficient. Reliable epidemiological data are, however, urgently needed to enable policy-makers as well as other stakeholders to develop, monitor and evaluate food safety measures intended to prevent and control foodborne disease. In response to this need, the WHO Department of Food Safety and Zoonoses has, in collaboration with multiple partners, launched a new Initiative to Estimate the Global Burden of Foodborne Disease.[1]
Microbiological contamination and foodborne illness
The aims of the Initiative to Estimate the Global Burden of Foodborne Diseases are to:
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Food safety and chemical safety aspects of heavy metals: policy analysis
The policy survey covers the following four topics from regional priority goal IV: food safety, chemical safety of pesticides, chemical safety of heavy metals (especially lead and mercury) and environmental noise. Two additional policy topics were also covered: ultraviolet radiation and radon in dwellings. The WHO working group agreed to consider them optional and hence beyond of the scope of this assessment.
Thirty-seven Member States responded to the four core policy topics, although not necessarily to all of them (for more information see Annex 1). The focus here is on food safety, the chemical safety of heavy metals and environmental noise and countries’ policy profiles are analysed along the six key aspects (for the methods, see Annex 2).
The policy profiles for food safety and chemical safety of heavy metals (lead and mercury) revealed rather distinct patterns. Food safety, with its symmetrical profile and high scores on all aspects except equity considerations, shows that this topic has been the focus of public policy throughout the Region. Overall, this was the topic with the highest scores of all EH policy topics screened using the WHO survey. For heavy metals, the scores are lower and the patterns differ substantially among the country groupings, reflecting the lack of a comprehensive approach to this topic as an environmental public health issue.[1]
Public governance
The high scores on policy development in all country groupings indicate the importance of food safety for many decades in the Member States. A closer look at national policy measures shows that compliance with food safety standards, regulations and international commitments both at EU and Region-wide level (the Codex Alimentarius) is the most frequently reported objective (85–100%). The same holds true for policy on modern approaches to risk management through the implementation of Hazard Analysis and Critical Control Point system in food industries, although the rates in the newly independent states are lower.
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