Water Supply and Quality
6.2.2 Exposure to chemical con- con-tamination
Chemical contamination of drinking-water provides a major route of exposure for a number of potential environmental health ef-fects, particularly in the CCEE and NIS. The main concerns seem to be nitrate, arsenic, fluoride and pesticides.
In six countries – Belarus, Bulgaria, Hun-gary, Lithuania, Romania and Slovakia – lo-cations are known where nitrate concen-trations in drinking-water are high enough to cause methaemoglobinaemia [16].
High nitrate concentrations in drinking-water from shallow wells are caused princip-ally by excessive fertilizer applications, large feedlots and rural septic tank effluents. A large part of the rural population is affected.
An association has been reported between the incidence of digestive tract cancer and high nitrate levels in drinking-water in Bor-sod County, Hungary, although food may also be involved [16].
In many of the Danube countries in par-ticular, bank-filtered river water is an import-ant source of drinking-water. In such situ-ations the problem lies less with long-term aquifer contamination by nitrates than with levels of nitrates in surface water and soil.
The actual sources are not always identified.
In management terms and in assessing the vulnerability of water resources to contami-nation, it is sometimes useful to make the distinction between surface water, shallow unprotected groundwater (such as alluvial aquifers) and groundwater protected by an impermeable layer and with a relatively dis-tant recharge zone.
Elevated nitrate levels would seem to be a serious problem in most of the districts in Romania [30]. Some 17 % of samples from over 2000 locations exceeded 100 mg/l, and a further 19 % exceeded 45 mg/l. This can be compared with the WHO guideline for ni-trates in drinking-water of 50 mg/l. Not sur-prisingly, a number of deaths from methae-moglobinaemia have been reported in babies from seriously affected areas such as Dolj and Mehedinti.
188 Water Supply and Quality
In Bulgaria also, nitrate levels regularly ex-ceed 100 mg/l. In Turgoviste, Stara Zagora and Burgas, values may reach 200 mg/l. The majority of the populations in these areas are drinking water with nitrate levels above the guideline values [31]. Methaemoglobinae-mia has again been reported.
Somlyody [32] calculates that 80 % of the drinking-water in Hungary comes from groundwater, and nitrate contamination can therefore have serious implications. This fig-ure for the use of groundwater differs con-siderably from the 10 % quoted after the Water Decade [33]. This may result from dif-ferent classifications of bank-filtered water, which is classified sometimes as ground-water and sometimes as surface ground-water. In view of the very high nitrate levels in ground-water in some parts of Hungary, a “plastic bag” water supply has been provided for about 700 settlements with 300 000 inhabit-ants [32]. Obviously, the options for control-ling nitrate will be different for bank-filtered sources and deeper aquifers.
In Slovakia, where nitrate values can ex-ceed 200 mg/l, over 2000 cases of methae-moglobinaemia with 12 deaths were re-ported in the 1970s. Incidence decreased by an order of magnitude in the 1980s following recognition of the problem and the supply of low-nitrate water to infants.
Around 57 % and 43 % of drinking-water in the Czech Republic is derived from surface water and groundwater, respectively [11].
Elevated nitrate concentrations have been recorded in groundwater in a number of areas. Values of up to 800 mg/l have been re-ported in the quaternary basin of the river Labe. Only 57 % of the treated water from a total of both sources complied with the national standard for drinking-water. The standard was exceeded for heavy metals at 123 localities (553 000 people exposed), for cyanides at 10 localities (10 000 people), for phenolics at 57 localities (230 000 people), for oil substances at 169 localities (1 million people) and for enhanced radioactivity at 100 localities (300 000 people).
In Poland, 84 % of water consumption is met from surface water and about 14 % from
underground sources [34]. A large part of the rural population is affected by nitrate pollution.
In Denmark, more than 95 % of drinking-water is abstracted from grounddrinking-water. The public supplies serve 95 % of the population, the remainder relying on individual wells or boreholes. High nitrate concentrations have forced some small waterworks to close. In 1980, the rate of pollution of potential groundwater resources increased, particu-larly around major cities due to the previous use of oil, petrol (older equipment and de-sign of petrol stations led to contamination problems in a number of countries) and chlorinated organic compounds. It may be necessary to close down some municipal water supply plants and to collect water from other parts of the area [35].
In Finland, nitrates and pesticides do not pose a serious problem to the public water supply [20]. In Norway, drinking-water quality is reported to be acceptable for the majority of the population, which is served by the larger waterworks [21].
High natural arsenic concentrations are recorded in drinking-water in parts of Hun-gary, including Bekes County (in the south-east) and the nearby districts of Arad, Li-pova and Ineu in Romania. Arsenic concen-trations reach 100 µg/l or more in water in both countries [16,36]. Some 100 000 people are potentially at risk in Romania, while a report by the Hungarian Academy of Sciences indicates that in Hungary nearly half a million people are exposed to drink-ing-water containing arsenic at levels above the guideline concentration of 10 µg/l.
Arsenic concentrations in the drinking-water of the Great Hungarian Plain are mod-erately well correlated with concentrations of arsenic in hair [37]. The highest accumu-lation was found in children, drawing atten-tion to the high level of risk in the young population.
Epidemiological studies carried out on some 25 000 people living in south-east Hun-gary, with access to deep-well water contami-nated with arsenic throughout their lives, re-vealed many cases of skin thickening and
in-creased pigmentation in both children and adults [38]. An increased incidence of pe-ripheral vascular disorders was not found [38]. A supply of “plastic-bagged” water in Bekes County has been the main public health response. Alternative drinking-water sources low in arsenic are often difficult to locate at the local level because groundwater in Hungary accounts for 90 % of the drink-ing-water. Similar epidemiological studies have not been carried out in Romania, but
“high rates” of skin cancer have been re-ported [16].
Further epidemiological research is required in Hungary and Romania to con-firm these results and to seek to establish a sound dose–response relationship. The total exposure of these populations to arsenic, as a result of intake from water, food and air, re-mains to be determined. Such research seems warranted, as arsenic-rich ground-water from deeper aquifers has been re-ported to be used in Hungary for irrigating local crops.
High concentrations of arsenic – up to 50 times the guideline values – have also been described in surface water and well-water near a copper smelter at Srednogorie in Bul-garia, and in water from the Topolnitsa river downstream from Srednogorie [39]. Expo-sure to arsenic can also occur via irrigated crops (especially rice) in the area.
High fluoride concentrations (up to 6.3 mg/l) occur in groundwater in central, east-ern and westeast-ern Estonia and the incidence of dental fluorosis in children is high. How-ever, insufficient fluoride (<0.5 mg/l) can be recorded in some surface waters. Elevated fluoride levels have been recorded in some well waters in Finland. Elevated fluoride le-vels in drinking-water, particularly well water, and associated dental and/or skeletal fluorosis have been described from locations in Bulgaria, Hungary, northern Kazakhstan (Pavlodar Kokchetau and Karaganda prov-inces), the Republic of Moldova, Spain, Tur-key (at Dogu-be-Yazit), Ukraine (Bucak) and also in eastern Siberia (Argun region) where concentrations can exceed 10 mg/l [40]. In the early 1990s, dental fluorosis was also
rec-ognized at locations across Europe, includ-ing sites in France, Germany, Italy, the United Kingdom and the former Yugoslavia, especially where the groundwater had elev-ated levels of fluoride. In areas of the United Kingdom where fluoride levels are low, flu-oride is added to drinking-water to raise con-centrations as high as 1.1 mg/l in order to re-duce dental caries in children [41]. This pol-icy is followed in various parts of Europe, the relative percentages of the population ex-posed to some degree of artificially elevated fluoride being, for example: Czechoslovakia 20, Finland 1.5, Ireland 50, Poland 4, Swit-zerland 4 and the United Kingdom 10.
High concentrations of pesticides and other inorganic and organic contaminants have been recorded in drinking-water at vari-ous locations in Europe, although their sig-nificance in terms of health effects is mostly unknown. In the Russian Federation, nearly half of the 60 million cubic metres of drink-ing-water piped daily to the population does not meet the national hygiene standards.
Around 24 % of drinking-water samples failed to meet the state standards for chemi-cal contaminants [18]. An additional prob-lem reported is that of disinfection chemi-cals and their by-products increasing expo-sure to halogenated organic compounds, par-ticularly in Moscow and other large cities.
Elevated concentrations of chlorinated pesticides have been recorded in the Danube and some of its tributaries; during 1979–
1982 in Yugoslavia, 93 % of samples con-tained raised levels of lindane and 40 % raised levels of aldrin, dieldrin and DDT.
The levels did not, however, exceed WHO guidelines [42].
Pesticides and organic chemicals are the focus of concerted control efforts in western Europe. In 1990–1991 in France, 0.7 % of the population (224 277 people) received drinking-water containing more than the WHO guideline value for atrazine of 2 µg/l, and there were a number of situations with increased exposure to trichloroethene and tetrachloroethene. There have been recent improvements in the quality of water sup-plied, but there are still three million people
190 Water Supply and Quality
in Italy who have drinking-water with trichlo-roethene and tetrachlotrichlo-roethene at levels up to 50 µg/l, and an unknown number are sup-plied with water containing up to 30 µg/l.
WHO [1] quotes a provisional guideline value for trichloroethene of up to 70 µg/l.
Failure of drinking-water samples to meet EU pesticide standards is increasing, for example in Germany and the United King-dom [23,43]. This may be attributable to more frequent monitoring for selected pesti-cides.
A recent epidemiological study in Finland on long-term exposure to chlorophenols identified an excess of soft tissue sarcomas and non-Hodgkin lymphomas in a popu-lation of 2000 [44]. A sawmill had used chlorophenols over a long period for wood preservation, and the population was ex-posed through drinking water and eating fish.
Despite a high level of compliance with standards in the United Kingdom (98.7 % of samples in 1991) there are continuing prob-lems in particular areas for nitrate, PAHs and lead that have resulted in more focused monitoring.
Elevated concentrations of metals have been found in drinking-water samples from areas in the Czech Republic, affecting 553 000 people [11].
High concentrations of lead in drinking-water have been reported but, with the ex-ception of infants, this route may be less im-portant than other exposure routes such as air and food. Detailed studies have been car-ried out only in a few countries, but evidence of neurobehavioural deficits among exposed children is reported to have been obtained in several of the CCEE.
The difficulties of establishing the effects of exposure to particular chemicals are well illustrated by the Lowermoor incident in 1988 in Cornwall, United Kingdom. Twenty tonnes of aluminium sulfate were acciden-tally released into the supply system, leading to aluminium concentrations typically of 10–
50 mg/l and up to 620 mg/l for about three days, far above the EU MAC of 0.2 mg/l [45]. Short-term gastrointestinal problems
were reported, but after a few days of flush-ing the concentration fell below 0.2 mg/l.
However, there continued to be complaints of effects (such as joint and muscle pain, fa-tigue, skin problems and memory loss) for a prolonged period.
The Lowermoor Incident Health Advisory Group [45,46] reviewed the likelihood of long-term effects. There were considerable difficulties in determining whether the longer-term effects reported by sufferers after acute exposure were attributable to the aluminium. Measurements of serum and bone aluminium and reviews of aluminium toxicity suggested that symptoms apparent after six months, such as joint and muscle pain or skin problems, could not be linked to aluminium exposure. For other problems such as memory loss or birth defects, alu-minium could neither be implicated nor dis-missed. The group suggested that a substan-tial proportion of real health problems might have arisen from anxiety associated with the incident, but that nevertheless routine obser-vation for longer-term effects should be im-plemented [45].
The Lowermoor incident demonstrates the difficulty of separating health effects arising from drinking-water contamination from general or parallel health problems.
Despite the body of toxicological evidence, it was not known what symptoms (other than acute toxic effects) could either be predicted or ruled out as a result of environmental ex-posure to aluminium.
The effects of combined exposure to a number of chemicals are rarely established, but a pilot study reported from Permsko-Krasnokam in Russiaa demonstrated a corre-lation between water quality in the river Kama (which has high levels of oxides and amino compounds, hydrocarbons, zinc, copper, iron and synthetic compounds) and human health. The effects reported included gastritis, duodenal ulcers, chronic nephritis, liver disease, gall bladder and pancreas prob-lems, stillbirths and premature births.
a Data supplied in country responses to the Con-cern for Europe’s Tomorrow protocol.
In general, there are substantial difficul-ties in identifying actual exposures and sequent health effects. For example, con-tamination of water is reported as non-com-pliance with standards, but it may not be clear whether the contaminated water was actually supplied, to how many people and for what length of time, or in which other way the contamination related to actual ex-posure. The other evident difficulty is that, in some areas, monitoring may not be ad-equate to identify contamination, such as that by pesticides. There is little possibility at present of assessing the total exposure of populations on a European scale (see also Chapter 10).