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Environmental Factors and Health

2 Environmental factors with possible health implications

This chapter gives a description of how humans are exposed to environmental factors in Denmark including descriptions of factors, sources, sectors, media etc. An overview is presented and delimitations of the present report are defined.

2.1 Health definition

Health is not an unambiguous concept. It is defined differently by different actors and each specific definition will lead to a certain focus in the health policy, just as a particular definition will facilitate some actions before others, and will in turn place more responsibility on some actors than others.

The World Health Organisation (WHO) defines health broadly: "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity" (www.who.dk).

The Danish council for preventive policies which is an official council, appointed by the Danish Ministry of Health, has the task of evaluating initiatives within the field of public health and prevention. The council has advocated a broad definition of health and it states that "health is a relative concept covering a person’s well-being including comfort and ability for self-expression". Health is thus not merely a medical, but also a psychological, social and cultural concept. Therefore health cannot be defined independently of a person’s social and cultural context. (www.folkesundhed.dk).

In 1999, the Danish Government initiated a ten-year prevention programme to improve public health. The programme is aimed at the causes of the relatively negative development in the average life expectancy of the Danes. The programme focuses on life style factors such as tobacco, alcohol, diet, exercise and overweight.

The present report deals with environmental factors influencing human health and well-being. Environmental factors can be physical, chemical or biological, and may include environmental factors in the environment, at home, in the working environment, and in all other places where humans reside also during e.g. transport and leisure time. The report, however, only covers environmental factors, which are under the jurisdiction of the Danish Environmental Protection Agency (DEPA) under the Ministry of Environment and Energy e.g. environmental factors in the environment and from chemical substances and products including cosmetics. The interfaces to other ministries are described in Chapter 3. Although the perception of human health and the factors affecting it remains unchanged, the focus on the responsibilities of DEPA leads to a number of important exclusions from the scope of the present report: Lifestyle factors such as food, tobacco, alcohol, exercise, etc. as well as human effects from accidents and national disaster are not included. Also impacts from occupational exposure and housing conditions are excluded.

2.2 Definitions of system components

2.2.1 Generic model of system

The environmental factors we are seeking to control are those that have en impact on human health and well-being. In the generic system environmental factors are the physical, chemical or biological components e.g. noise, cadmium or the bacteria Salmonella capable of accommodating an effect, e.g. emissions from a factory. In the context of ensuring human health and well-being it is important to follow the path of the factor to regulate or prevent it in the most appropriate way.

To identify components of the system between the emission and the potential human effects, a generic model for the ’life cycle’ of an environmental factor is presented:

In fact, the linearity of the 'cradle to grave' process in this model does not provide a full picture, because loops may occur for many chemical substances and products during production, formulation, processing, use, discharge and recovery, and because exposure may occur at all stages.

2.2.2 Development of and exposure to environmental factors

The generic model applied in the field of health and environment is shown in figure 2.1.

Figure 2.1
Conceptual model for the transport and exposure of environmental factors. Arrows indicate routes of environmental factors.

The primary sources in various sectors are responsible for generating the environmental factor, which is emitted directly to the environmental media or carried in products and waste for later release to the environment. The environmental factor may be the same and stable in all compartments of the above system or it may be transformed and finally degraded.

Humans may be exposed to the environmental factor in all compartments in the different sectors, by contact with products and waste, or through contaminated environmental media. The exposure will be a function of the occurrence and magnitude of the factor and the occurrence and behaviour of humans in time and space.

Regulation of environmental factors may take place in all boxes and intersect all the route paths (arrows). Obviously, the use of severe or comprehensive instruments at the source will lead to greater downstream effects.

An example of applying approach

Polyaromatic hydrocarbons (PAHs) from traffic may be used as an example: The traffic's emission of PAHs will enter the generic system with the sector as traffic and combustion engines as the primary source. The product/waste step may be omitted here because emissions occur directly to the air. Air is reckoned as the environmental media with urban air as the point of regulatory action. PAHs constitute the environmental factor, which is carried by particles.

Table 2.1 gives examples of regulatory actions aimed at different parts of the system.

Table 2.1
Examples of regulatory actions aiming at different parts of the system.

2.2.3 Components

Definitions of factors, sources and media etc. are presented below.

Environmental factor

The environmental factor is herein defined as the external physical, chemical or biological component in or of the environment, which may affect human health and well-being. Some examples are micro-organisms, noise, airborne particles, pesticides, metals and radiation.

In cases where the actual factor/stressor can not be identified precisely, or in cases where several factors are operating at the same time, it may be useful to choose an indicator for the environmental factor(s) for regulatory purposes. In connection with air pollution, one could say, as an example, that the limit value for particles (expressed in mass of airborne particles/volume unit in air) may be an indicator for those sub-fractions of the particles that may be more closely associated with the harmful effects. Similarly, the E.coli number is merely an indicator of faecal contamination in bathing water, while the pathogenic effects are connected to other micro-organisms (see section 2.3).

Sectors/Primary sources

This designates the entity responsible for generating the environmental factor. The definition of primary sources and sectors must be understood in a broad sense to include all emitters. Primary sources are the actual emitters of the environmental factors e.g. a factory, a farm, a power plant etc., whereas the sectors may be industry, agriculture, waste management, etc. Some primary sources such as landfills or other waste disposal sites are filled with used consumer products, which were once new, and at that time derived from another primary source. However, in a process view, emitters are equally good sources regardless of the age of the raw materials.

Products and Waste

Products and waste are carriers of the environmental factors. This compartment has been defined because there are some borderline problems in separating factors from more or less well defined conglomerates of factors, which approach both media and sectors. Factors may be ’hidden’ or lumped together as in ’building materials’ or ’chemical products’. To separate these issues from ’real’ sectors and media these are generically termed vehicles (transporting many factors) and here named ’Products and Waste’. For the sake of providing an overview it is not crucial whether the environmental factors are ’travelling’ in products or in waste, and they may conceptually be grouped together.

Environmental media

The environmental factors subside in the air, soil and water media. For reasons of accuracy and estimation of exposure these may be subdivided into a number of other categories, e.g. groundwater, sediment, organisms living/ growing in the compartment (food items), or subsections of all mentioned. A number of regulations take place here regarding the protection of the environment, and they will in many cases (e.g. air quality) have a human health dimension. For regulatory purposes, the environmental media are often sub-divided. For example, the aquatic media into drinking water, surface water or bathing water for which different regulation applies.

Humans

Humans and human populations are, for the sake of completeness, included in the conceptual model, although it is obvious that they are not deliberate ’targets’ of the environmental factors. However, it does take both the occurrence of the factor and of the humans to generate an exposure situation which may cause adverse health effects.

Regulatory actions

The regulatory actions will aim at influencing the exposure of humans, i.e. provide a reduction or elimination of the probability of co-occurrence of humans and the factor at the human/environment interface. Regulatory actions may include the use of bans, quality criteria, substitution programmes and a number of other instruments operated at any part of the system (see figure 2.1).

Environmental factors may impact on human health, but in many cases the extent will be difficult to verify. If regulations follow an epidemiological approach this would tend to let the regulatory actions follow the effects, and they would lag behind. A great deal of effort is therefore spent on generating information and regulation based on the predicted risks with the intention of prevention rather than based on the retrospective knowledge. Risk is assessed on e.g. predictions of effects to humans based on experience, test results on various organisms, and knowledge of physical and chemical characteristics of the potential factor.

2.3 Environmental health factors

A complete list of environmental factors is impossible, as numerous chemicals and pathogenic micro-organisms subsist in the environment, but not all have health effects and if we allow for some generalisation, a list of groups of factors can be derived:

	Microbiological factors (e.g. pathogenic micro-organisms)
	Physical factors (e.g. noise, UV-radiation, radioactivity)
	Chemical factors (inorganic and organic chemicals)
	Naturally occurring substances
	Man-made or anthropogenic chemical substances.

Table 2.2
Examples of environmental factors , their categories and main risks

2.3.1 Microbiological factors

Pathogenic agents

Water, food and organic material may contain pathogens, typically bacteria, and airborne biological contamination is also well known. The infections caused by e.g. Campylobacter and Salmonella in food may also occur directly from the environment: Salmonella is not uncommon in manure and Campylobacter occurs in surface waters. However, most frequently the exposure of humans seems to be from intake of food and drink, and less often related to exposure in the ambient environment (e.g. ingestion of water during bathing or swimming).

Microbiological agents

Generally, micro-organisms constitute an enormous ’realm’ with a multitude of bacteria, viruses, fungi, protozoa, planktonic algae and many specific species. A well-known example of a microbiological health factor is the recurring blooms of blue-green algae releasing toxic compounds to the environment.

In recent years, genetically modified organisms (GMOs) have been permitted in some countries for use in the environment, and the risks related to GMOs may be included under this heading. Plasmids and other components of the sub-cellular level may also be included as environmental factors with a potential for adverse effects in the environment and/or human health, although the knowledge within this area is presently limited.

2.3.2 Physical factors

Noise and radiation differ from the majority of other environmental factors in being wave dispersed and physical rather than chemical or biological.

Noise

Noise must be considered as one of the most significant physical environmental factors. Not because it has the most severe impact, but because noise is perceived by humans far below the doses which will cause serious damage to human health. It may be a nuisance in a broad range of exposure levels and may contribute to adverse health effects like disturbance of rest and sleep, stress, hypertension and ischemic heart disease.

Radiation

These other typical wave dispersed factors cannot be sensed directly by humans and therefore sometimes lead to more severe effects because they may go unnoticed until it is too late. These factors include emissions from radioactive compounds and materials, products emitting radio-frequencies, or ultraviolet radiation (UV). Exposure to UV-light may be indirectly linked to use and release of chemicals (the CFCs) that catalyse the break down of the stratospheric ozone layer, which normally absorbs and protect us from the harmful effects caused by the UV-light emitted by the sun.

Particles

One often regulated issue, which is physical in the sense that it is an object, is the concentration of airborne particles. Especially in urban areas, a great effort is directed into measuring and controlling particles in the air. At present, it is not clear whether it is the particles as physical entities (and the number of these) or the chemical content of the particles (or a combination of both) that is the primary factor for induction of adverse health effects caused by particles.

2.3.3 Chemical factors

It is assumed that some 100,000 chemical substances are marketed on a global level. For Denmark it has been estimated that 20,000 substances, 100,000 chemical products and 200,000 goods/industrial products are on the market.

The vast number of substances can be organised in various ways depending on the necessary level of detail and knowledge. The overall categorisation of substances may be undertaken by dividing the chemicals into natural or man-made (anthropogenic) chemicals, organic or inorganic chemicals, high production volume chemicals or those produced at smaller volumes. However, there are numerous ways to organise the topic. In regulation substances are usually categorised according to their hazardous properties and their field of application. This will be dealt with in detail in chapter 10 on Chemicals.

Naturally occurring substances

The substances and compounds occurring naturally can be both organic and inorganic. Powerful toxicants, such as the in-organics hydrogen sulphide, cyanide or the organic methyl mercury or dioxins are found as a result of natural processes. Plants, animals and fungi may produce biologically active substances, some of which may be acutely toxic or pose other critical effects such as sensitising or carcinogenic effects. Some natural toxicants have a geochemical origin, but some fall in the borderline area to biological agents since they are produced by organisms. Pragmatically, those recognised as substances, and monitored as such, are dealt with under ’Naturally occurring substances’ and those identified as the parent micro-organism are dealt with under microbiological factors.

Some naturally occurring substances are biologically active and may affect humans typically through exposure in food or water. Obviously, compounds interfering with actions of hormones and other signal compounds have the potential to give rise to effects; recent examples include the phytoestrogens. This is however, a complicated topic since estrogenic hormones are both naturally occurring substances excreted by mammals and a component of applications in synthetic pharmaceuticals, both of which may occur in waste fractions.

Other natural elements are an integrated part of the environment and always have been. Some have beneficial effects as nutrients, micro-nutrients and co-factors in the human diet or may even be essential, but the very same elements may be toxic in concentrations or doses above a certain level.

The levels of inorganic compounds and elements with potential for adverse effects on human health are enriched in the industrialised society. It is not only the metals, but also a range of compounds e.g. sulphide, cyanide or ammonia. The substances and compounds are sometimes vital for the industrial production as base chemicals e.g. chlorine and various acids and bases.

Man-made chemical substances

The post-industrial era has been called the ’Chemical Age’ since the solution offered to many technical problems involves the use of new or existing chemicals or formulations. Most of these compounds are produced for specific purposes, and their use and the products they are part of permeate every aspect of the modern society. A few examples of such compounds are the polymer plastics polyethylene or polyvinyl chloride, detergents such as alcohol ethoxylates or linear alkybenzene sulphonates or even compounds used in pesticides or pharmaceuticals.

The chemicals may be divided into several categories depending on their application pattern, which also influences the potential exposure of humans:

	Industrial bulk chemicals (substances and products)
	Agrochemicals and biocides
	Household and hygiene products
	Human and veterinary pharmaceuticals

The latter is not addressed in the present project, but receives increasing attention due to the focus on endocrine disrupters and the possible occurrence of multi-resistance to antibiotics in pathogenic bacteria.

In general, only a fraction of the anthropogenic substances used and produced in an industrialised society have inherent properties rendering them acutely hazardous for humans. The problem is as much the huge quantities and the many potential exposure situations during the life cycle of a substance from synthesis to release via waste emission or as part of a product. The life cycle may be long for the product and the substance may reside in the human sphere or in nature for long periods of time, if it is not or only slowly degradable. Lack of biodegradation and bioaccumulative properties are therefore unwanted, because such properties leads to a build-up of the substance in food chains that may cause chronic effects after prolonged low-dose exposure. Low level and mixed exposure are especially of concern in relation to chronic effects such as immunotoxic, neurotoxic, carcinogenic and reproductive effects.

The following table provides an overview of the interaction between the major sources of environmental factors and the primary exposure media. An empty cell is not to be taken as evidence of an exposure not being possible in this combination, but rather that it is not a major route of exposure.

Table 2.3
Overview of primary environmental factors in basic environmental media. Chemicals (C), microbiological (M) and physical factors (Noise and chemical induced UV Radiation) are shown.

* Including possible exposure through aerosols.

2.4 Primary sources and producers

The sources and producers comprise the sector or entity responsible for producing the environmental factor, and as mentioned in the definition a sector must be understood in a broad sense. The primary sources and producers of environmental factors are ubiquitous in society. A broad range of classical emitters such as industry, traffic and agriculture can be mentioned, but also a number of disposal facilities can be included, and even humans can be a primary source. A list of the most direct sources includes:

	Industry
	Agriculture and forestry
	Energy production
	Waste disposal and treatment facilities
	Combustion engines (transport)
	Households
	Humans (institutions, hospitals)

2.4.1 Industry

Listed activities and installations

The classical source of pollution is the industrial sector. The most important industries, when talking about pollution, are the so-called listed activities (according to the Environmental Protection Act) and installations which all need an environmental permit. These activities and installations include activities ranging from for example processing and treatment of metals, refineries, chemical and biological production to waste treatment and motor racing tracks. As sources, these sectors are characterised by having an impact on the environment, which needs to be regulated before the activities can take place.

Non-listed activities

The non-listed activities and installations consist of small and medium sized enterprises, most of them producing the same as a listed activity but on a smaller scale. These enterprises do not need a permit but must announce their establishment to the local authorities before starting the activities. The emission of environmental factors from these enterprises is not as high as from the listed activities, but is still of some importance.

Other activities

Other activities include restaurants, offices, dentists, etc. These activities do not seem to be major sources of environmental factors although they generate some waste and may generate noise and odour.

Backyard business

In sectors where demand is high (and in growing economies) entrepreneurs often open a plethora of very small backyard businesses. In terms of sources and producers of environmental health factors, this type of activity may be the source of much emission, which often occurs in or close to residential areas.

2.4.2 Agriculture and forestry

Agriculture

There is a considerable difference in the source characteristics between extensive and intensive farming. Extensive production, such as grass lands and cattle rearing typically does not involve the use of fertilisers, irrigation, pesticides or high energy consumption, whereas intensive agriculture does.

Some crops are more dependent on the use of water, fertilisers and pesticides and may be more labour intensive than others. This may give rise to significant differences in the risk of direct or indirect effects on the population in the area.

Large scale ’industrialised’ animal husbandry also leads to large-scale production of waste in the form of manure etc. Many examples of accidental emissions of stored manure polluting surface waters are known. Moreover evaporation of ammonia from manure stored in tanks or applied to farmlands gives a critical nutrient load to vulnerable ecosystems, but may also affect human health and well-being of neighbours.

Recently, attention has been drawn to the potential risk associated with the use of antibiotics as growth promoters in this industry. The concern is that the constant selection pressure applied to the bacteria of the animals may trigger the emergence of multi-resistant forms of pathogenic micro-organisms, which are spread in the environment with manure. Specific antibiotic growth promoters have been banned and/or restricted in Denmark due to this concern.

Forestry

Forestry in natural woods may be comparable to extensive farming, whereas in plantations often both fertilisers/sludge amendment and use of pesticides find its place, especially in production of decorative greenery.

2.4.3 Energy production

Fossil fuels

The energy production is often centralised when using fossil fuels, especially if coal is the source of energy. This may lead to problematic emissions of particles, PAHs, NO_x, SO₂ and heavy metals from smokestacks. It is however, also more feasible to control emissions from fewer sites. The filter dust, the fly ash and slag from coal based energy production require special attendance due to the retained pollutants, especially the heavy metals. For these wastes, special depots are created and various recycling methods are used, e.g. for use in roads, building- and construction materials.

Renewable resources

Energy production based on wind, solar, water and other renewable resources does not infer significant emission of environmental factors affecting human health. Except for hydropower dams, this is typically a decentralised sector although windmill parks are emerging as a feasible solution to one of the nuisances – the noise emitted from the revolving blades of the mills.

Transport

Combustion engines are the source of a number of environmental factors and they are believed to play a major role in causing adverse health effects, i.e. increased mortality and morbidity in the population. Emissions from transportation occur from a great number of small sources and they primarily take place in areas with a large population. Furthermore, the emissions occur approximately at breathing level. Monitoring of traffic emissions therefore has high priority in Denmark and internationally. Also the composition of the fuel and the use of additives may give rise to problems. Previously, the use of organic lead in gasoline was of great concern due to the toxic effects of lead. Today the extended use of MTBE in gasoline is identified as problematic due to a high risk of contamination of the groundwater, which is the primary drinking water resource in Denmark.

2.4.4 Waste disposal and treatment facilities

The very existence of waste disposal and treatment facilities is a matter of human health concern. The aim of waste handling is to minimise human exposure to waste that may be a risk for human health, e.g. in the form of infectious, flammable or otherwise hazardous materials.

Landfills

Landfills are often seen as long-term or even final solutions to the dissipation of problems of environmental factors in the form of waste. Nevertheless, waste disposal by landfilling may lead to direct exposure of humans via contaminated or infectious dust or spores, noxious, flammable or explosive gases especially if residential areas are in close proximity or reuse/recycle activities takes place on site. Percolating water from landfills may be severely polluted and may contaminate groundwater or surface waters. Therefore the use of landfilling is minimised as far as possible, and no household-waste is land filled.

The former frequent practise of burning garbage and waste at landfills has been abandoned in Denmark since this may lead to nuisance and health problems in the local environment due to smoke and contamination. The low temperature of such burning may lead to increased emission of polycyclic aromatic hydrocarbons and polychlorinated dioxins and furans, types of environmental contaminants which it is actively sought to reduce.

Waste incineration

Incineration at high temperatures limits the generation of dioxins and furans, but the stack emissions of particles and other contaminants are still a potential source of health problems. In consequence, most waste incineration facilities are equipped with various emission reduction processes; e.g. dust filters and smoke scrubbers. The reduction measures reduce the emission to the environment. It will give rise to new waste products, e.g. filter dust, which can be handled, utilised and/or stored in a secure manner.

Sewage treatment

Sewage treatment also leads to emission especially by the inherent release of sludge and effluent water. Due to the affinity to particles of many anthropogenic substances released from industry and household, the sewage sludge may contain significant amounts of heavy metals and organic micro-pollutants.

The common aeration of the slurry in a sewage treatment plant may lead to emission of volatile compounds, semi-volatile compounds and micro-organisms due to the effect of stripping (transport in aerosols). Again, these impacts are confined to the areas in the vicinity of sewage treatment plants rather than on the population as a whole.

2.4.5 Humans

Humans may also be a direct source of environmental factors in some special cases. These includes situations where humans may infect each other in the same ’media’ e.g. in swimming pools and bathing waters through contamination of the water via faeces or from the skin.

2.5 Products and waste

In some instances the primary producer releases the environmental factor directly as e.g. noise or air pollution from traffic, but often the environmental factors are carried to the environment in products or waste coming from the producer. Such products may be ordinary consumer products, materials used for building and construction or e.g. agrochemicals and biocides. In parallel, waste streams also contains environmental factors with a potential for affecting human health. These wastes may include hazardous waste, house-hold waste and a number of more or less well defined wastes from industry, energy production and agriculture.

It is not crucial whether environmental factors are ’travelling’ in products or in waste, but common for both is that the factors may be ’hidden’ or lumped together as in ’building materials’, in ’consumer goods’ or ‘chemical substances and products’. A non-exhaustive list of typical products and wastes include:

	consumer goods
	fertilisers, agrochemicals and biocides
	materials used for building and construction
	wastewater
	industrial waste and hazardous waste
	non-industrial waste.

2.5.1 Chemical substances and (consumer) products

Shelf chemicals and chemical products

The chemicals sold to professionals and laymen are the source of numerous direct exposures of humans to environmental factors. In Denmark about 8 million tonnes of chemicals are consumed each year in industry, agriculture and households, representing about 100,000 chemical products that include 20,000 chemical substances (DEPA 1996).

Chemical substances and preparations comprise a plethora of items, uses and potential exposures. The chemical substances (i.e. when chemicals are not mixed with one another) that reach the non-professional user are mostly solvents and acids. Typical exposure is during various rinsing and cleaning activities. A relatively frequent accidental incident is oral intake by children and dermal exposures. Chemical preparations are a far more diverse group including for example paints and varnishes, cosmetics, detergents, glues and cleaning agents. The uses and potential exposures obviously span even further than for substances. Some may have profound impact on indoor air quality (paints and varnishes), whereas the use of others may lead to repetitive and prolonged exposure (cosmetics).

A great number of different chemical substances and products are in retail and a considerable effort is directed into labelling the chemical substances with warnings, limiting the anticipated exposures by restricting the use or prescribing specific protective equipment.

The classification and labelling of chemical substances are important instruments in securing a safe and unified way of controlling the use of chemical substances e.g. for what purpose they are used, how they are used etc. The use of classification and labelling is further described in chapter 10.

Substances in consumer goods

Many consumer products are not perceived as the possible source of environmental factors, but chemical substances and products are used in the production of consumer goods. The chemical substances may reside in the consumer product because they serve a specific purpose as a part of the structural material, for stabilisation, for decoration or similar. Examples of chemical substances, which occurred deliberately in consumer products, but are now undesired and sometimes banned are cadmium and lead used for colouring in enamel and glazing, phthalate plastisicers in PVC, and certain non-ionic surface active compounds in various health care products.

It also happens that a residual concentration or contamination from a substance in the produced goods is considered problematic for human health. Most often the concentrations are low, and it is not acute toxicity which is of concern, but rather the long-term effects associated with the substances. Benzene in naphtha used in print colours, residual chlorinated pesticides and dioxin in clothes, nickel in numerous alloyed materials and as contaminants in other, are examples of undesired compounds occurring, not as a result of a deliberate addition during production, but as component of, or contaminant in some material or process in the production line.

Indoor living conditions may be greatly affected by the choice of building materials because of the long-term exposure, little exchange of indoor air, and the huge areas/amount of material potentially emitted from the material surface. Volatile compounds receive special attention since evaporation from walls and floors may lead to high concentration in confined areas with large surfaces. However, the emission of plasticisers from PVC flooring, especially during cleaning with detergents has also received attention.

2.5.2 Fertilisers, agrochemicals and biocides

Fertilisers

Fertilisers and other soil amendment materials may have human health impacts. Applying sewage sludge to agricultural land implies a risk of human contact with sludge, but also spreading of manure may impose severe smell problems and maybe also health effects by inhalation of ammonia. Aerosols containing pathogenic micro-organisms may be formed during spreading of manure and transported over longer distances. Some artificial (phosphorous) fertiliser products have prior been shown to contain cadmium in amounts that Danish authorities considered unacceptable because of possible uptake in plants. Other impacts may be residual concentrations of nitrate in drinking water and food, which are monitored and quality limit values exist.

Pesticides

Pesticides are by virtue biologically active compounds and the possible effects on humans from pesticide residues in drinking water and food entails large scale monitoring programmes to ensure that basic water and food is safe for human health. The use and application of pesticides is a carefully regulated area. Over the past 50 years many pesticides have appeared in the market and disappeared again. Some have been severely restricted or banned due to human health concerns, notably the organo-mercury and organo-chlorine compounds.

Biocides

Pesticides used elsewhere than in agriculture are called biocides. This may be in aquaculture, ship paints, disinfection, slimicides in cooling systems and a number of other use areas (23 are defined in the EU Biocidal Products Directive, 98/8/EEC). Biocides have a complex use pattern and will presumably be used by a greater percentage of non-professional users compared to pesticides. Biocides may also be spread in residential areas e.g. to combat insects, and may represent a greater risk of exposure for humans.

Biocides occur in many chemical products for preservation purposes, such as in paints and cleansing agents, but biocides are also used in building and construction materials, fabrics and other materials to prevent the biological degradation processes. Obviously, products with a long shelf life or high durability are potentially more likely to be biocide-containing.

2.5.3 Industrial waste

Industrial waste can contain material that may affect human health. However, a system for recognising hazardous waste (which is based on criteria similar to classification of chemical substances and preparations) removes much of the potential exposure and risk. Some minor exposures may still remain, and could possibly contribute to negative impacts on human health, especially in the local environment of the industrial site.

Hazardous waste

Industry produces waste as well as other commercial sectors, but the generation of hazardous waste or products that eventually turn in to hazardous waste are recognised as a great potential danger to human health. The types of hazardous waste and components are separated in many categories, but may for example be corrosive, toxic, irritating or explosive. Often strong acids and bases are among the health problems in industrial waste.

2.5.4 Non-industrial waste

Household waste

Household waste or garbage is generally not considered a significant source of human health environmental factors to the general population (but is a source of health factors in the working environment, notably micro-organisms). In Denmark, bio-treatment, or incineration facilities, receives the household wastes. Local burning of such waste may give rise to emissions of a number of unwanted pollutants, notably dioxins and furans.

Wastewater

Public sewage systems handle more than 90% of the wastewater in Denmark, the majority of the rest being led to septic tanks or rarely directly to recipient. Limit values are imposed for the treated effluent and for the produced sludge. Exposure to wastewater or aerosols originating in the treatment process is therefore not common for humans in Denmark. Workers in the sewage treatment facilities may, however, be exposed to wastewater, air or sludge containing environmental factors.

Since sludge is used as a fertiliser in agriculture there is a potential route for exposure to sludge during children's play or other activities in the fields.

Compost

Garden and household compost are in general not considered problematic in terms of environmental factors affecting human health, however, certain problems with infections and breathing of fungi spores are reported from workers in central compost facilities. Effects on the health of the population as such are not envisaged.

Human waste

Household waste from hospitals and other institutions with personal hygiene performed by professionals may contain faeces, urine or otherwise contaminated waste. In cases where such waste is brought to landfills or composted the spreading of infectious material is possible.

2.6 Environmental media and exposure of humans

2.6.1 Environmental media

The environmental factors eventually reaches the environmental media, which comprise the basic air, soil and water compartments. The fate of the factor in the environment is depending on characteristics of the factor itself and of the part of the environmental media where it resides.

The physical-chemical properties of the chemical will govern its distribution in the environment, e.g. volatile compounds will primarily be found in the air media, hydrophilic compounds will mostly be found in water, whereas the strongly hydrophobic compounds will occur in the sludge, sediment or in the biota. The chemical may also be degraded in the environment and the degradation products may be either more or less toxic than the original compound. The degradation of the chemical will depend on characteristics of the chemical itself, but also on the conditions of the environment (occurrence of micro-organisms, nutrient, humidity etc). In the same way the survival of pathogen micro-organisms will depend on the physical, chemical and biological conditions of the environment (temperature, nutrients, oxygen, competition from other micro-organisms etc.)

Soil contamination with mineral oil may be taken as an example. Some of the oil components will be strongly absorbed by soil particles and stay immobile in the soil. Some will be dissolved in percolating water and eventually reach the groundwater. Others will evaporate from the soil to the air and possibly to indoor air in houses build on contaminated land. Degradation of the oil components may take place in all these situations, and the mechanism and speed of degradation will depend on the chemical and physical conditions e.g. the presence of oxygen, water, organic material, the pH of the soil, the mineral content etc.

2.6.2 Exposure of humans

All humans are exposed to environmental factors e.g. through the air we inhale, through the water we drink and through contact with different substances and preparations etc. However we are differently exposed due to differences in our environment and our behaviour. The origin of these differences can be:

	Locality of home and daily activities (city or country-side, special environments)
	Activities we perform in different environments (activities causing special exposure during work, transport, leisure, sports, children's play etc.)
	Choice of food and products such as clothes, cosmetics, jewellery, household chemicals etc
	Housing conditions (building materials, ventilation etc.).

Exposure routes can be direct or indirect. Examples of direct exposure routes are:

	Inhalation of contaminated air
	Inhalation of aerosols containing pathogenic micro-organisms
	Ingestion of contaminated soil or water
	Skin contact with products or contaminated media

whereas indirect exposure may be:

	Ingestion of foodstuff originating from contaminated land
	Wearing contaminated clothes
	Inhalation of vapours from contaminated soil or water.

Vulnerable groups, other risk factors and possible exposure groups are considered in determining a reasonable ’worst case’ direct and indirect exposures for humans, as for example in the European Union Environmental Risk Assessment for Chemicals, the EU TGD (EU 1996).

In addition to the differences in human exposure, differences also exist in the vulnerability of individuals and of special groups. Even for the same individual, the vulnerability may change depending on the person's general health and presence of other stressors. These individual differences may be difficult to handle in a regulatory approach, however, considerations for certain vulnerable groups are central in Danish (and international regulations), e.g. the specific focus on the protection of children and pregnant women.

Children are considered vulnerable due to their physiological growth, development of organs, relatively greater inhalation of air etc., but also due to children activities such as play, putting things in the mouth etc. Thus small children are considered being the target group to protect with respect to contaminated soil, as they may be more vulnerable to chemical exposure and as they are most heavily exposed to soil (direct soil ingestion, dermal soil contact).

Pregnant women are considered another vulnerable group, especially because of the rapid growth and vulnerable periods of the foetus.

2.6.3 Policy in relation to the protection of human health

In recent years focus has increased on the possible influence of environmental factors on public health. During the latest decades an increased presence of allergy amongst the population has been observed, which can hardly be explained by genetic dispositions alone. Because allergic sufferings are developed during infancy, focus has been on exposure to infants and minor children.

The different environmental factors such as indoor climate, contaminated air, foodstuff and different types of chemical exposures are being studied in particular. Furthermore, in Denmark one finds the world largest incidence of testicle cancer, a very high frequency of mutations in the male sex organs, men with a poor sperm quality and for the women, a high frequency of breast cancer. The hormone system and its function have a very important role in those diseases and effects. The influence of environmental factors on the hormonal balance and its development cannot be disregarded in this context. Especially, there is now increased awareness to the fact that in certain periods in embryos and children’s development they are very sensitive to the exposure of chemicals with hormonal disturbing effects. Those chemicals can have fatal consequences for normal development and normal function, especially in relation to the development of the immune system, the central nerve system and the sex organs.

The chemicals that can effect the fertility are seen among animals and organism in the environment and among humans in special working environments. Therefore, the possibilities of damaging exposures from environmental factors to the public health cannot be disregarded. This is also supported by international investigations, which prove coherence between decreased intelligence and lack of learning ability among children, exposed to environmental factors e.g. lead, mercury, PCB and dioxins during the embryonic stage and/or the years of growth.

In addition, monitoring of environmental factors in the environment has increased at the same time. More attention is paid to the extensive human impact caused by chemicals through soil, air, water, consumables, foodstuffs etc., where it is difficult to predict the health consequences of the totality of the many different exposures.

In the light off the consequences a deterioration of our environment may cause, it is important to use the precautionary principle as a basis in assessments and regulations. In this way, measures can be taken and possible dangers can be remedied before there is a 100 percent scientific proof for often very complicated cause-effect relationships.

When it comes to the Danish environmental regulations, the basic objective is the maintenance of a sustainable environment with special protection of the basic media soil, air and water. Only a very low degree of human exposure of environmental factors originating from human activity is allowed, because other exposure routes with the same environmental factor may often dominate (through foodstuff, chemical products etc.). Often no more than 1-10% of this dose is tolerated through the basic media when the daily acceptable ingestion is assessed.

By the determination of e.g. quality criteria it is the aim to protect all humans, with special consideration of particularly vulnerable and exposed groups in the population (e.g. sick or weakened persons, children and pregnant women). At the same time, safety factors are applied extensively in consideration of the uncertainty in the basic health data (the principles here off are presented in appendix 1).

In Denmark, the protection level is generally regarded as high considered in relation to the regulation areas of the Ministry of Environment and Energy. As it may be seen in the following chapters, it is however at present not possible to maintain a protection level for the public health within all areas, as seen within, e.g., the area of air contamination.

2.6.4 Regulatory approach

Humans are often exposed to the environmental media under circumstances that dictate the use of a particular media subsection, where the exposure may be regulated. Such media are e.g. bathing water and drinking water, indoor air and ambient air, natural soil and agricultural soil.

In some cases, such media may also comprise more than one environmental sub-media, e.g. drinking water may be composed of groundwater and/or surface water.

For obvious reasons it is difficult to regulate the exposure in the ambient environment by regulatory actions on the environment, since the exposure concentrations cannot easily be turned lower. Concerning the environment itself, the regulatory approach is the one of monitoring and setting quality standards, limit values etc. The concentrations in the environment may however be regulated at the source (by emission control, ban of chemicals etc.) or at products and waste (e.g. labelling, substitution of chemicals). It is also possible to regulate the human behaviour. If the counts of thermotolerant coliform bacteria in bathing water exceed the quality limit, bathing is not recommended, vulnerable groups (e.g. children) are warned or bathing may even be prohibited. Similar restrictions can be invoked for many other environmental factors.

2.7 References

DEPA (1996): "Chemicals – Status and Perspectives. Excerpts from a discussion paper from DEPA, English Summary and List of Undesirable Substances".

homepage: www.who.dk

homepage: www.folkesundhed.dk

EU Coucil Directive 98/8/EC concerning the placing of Biocidal Product on the Market.

EU Commission (1996): Technical Guidance Documents in support of the Commission directive 93/67/EEC on Risk Assessment for New Notified Substances and Commission Regulation (EC) 1488/94 on Risk Assessment for Existing Substances.

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