The impact of the hyperacid Ijen Crater Lake: risks of excess fluoride to human health

https://doi.org/10.1016/j.scitotenv.2004.12.007Get rights and content

Abstract

The Asembagus irrigation area (East Java, Indonesia) receives a high input of fluoride (F) via surface water that partially originates from the hyperacid crater lake of the Ijen volcano. Endemic dental fluorosis among local residents has been ascribed to F in water wells. In this study, the total F intake by children and adults was estimated, based on concentrations in well waters and foods throughout the area. These values were compared with the Lowest Observed Adverse Effect Level (LOAEL) for dental fluorosis among children and skeletal fluorosis among adults. Fluorosis hazard maps were prepared, identifying the most hazardous locations in the area. It was concluded that there is not only a high risk of dental fluorosis, but also of skeletal fluorosis. Based on the total daily intake, the lowest F concentration in drinking water that poses a risk of developing fluorosis is approximately 0.5 mg/l for dental fluorosis and 1.1 mg/l for skeletal fluorosis. This is below 1.5 mg/l, which is both the guideline value for drinking water from the World Health Organization (WHO) and the Indonesian drinking water standard. This is the first documented case of human health problems that may be directly associated with natural pollutants originating from a volcano-hosted crater lake.

Introduction

Dental fluorosis is endemic in residents of the Asembagus coastal area (East Java, Indonesia), where agricultural land is irrigated with F-rich river water originating from the hyperacid Ijen Crater Lake (Fig. 1). The fluorosis problem has been attributed to high fluoride concentrations in local water wells (Rai, 1980, Budipramana et al., 2002). Budipramana et al. (2002) found a prevalence of dental fluorosis of 96% among 6–12 year old school children, tested in ten villages of the Asembagus subdistrict, supporting earlier findings (Budipramana et al., 2002). Dental fluorosis was already observed where well water contained as little as ∼0.5 mg/l F, which is below the World Health Organization (WHO) guideline value of 1.5 mg/l F for drinking water (WHO, 1996). This guideline value has been adopted by the Indonesian government as the national drinking water standard.

Chronic exposure to F can cause various adverse effects, whereby the disturbance of bone tissue structure due to excessive incorporation of F is regarded as critical. The first symptom is discoloration of teeth, as these become porous and brittle (dental fluorosis). Dental fluorosis can arise until the age of 6 to 8 years, when the development of teeth is more or less completed. In the second stage, the skeleton is affected (skeletal fluorosis) resulting in e.g. chronic joint pain and osteosclerosis. It occurs after long-term exposure and is therefore mainly observed among adults. The most severe form is crippling skeletal fluorosis, which is associated with symptoms such as restricted movement of the joints and skeletal deformities (WHO, 2002). The Lowest Observed Adverse Effect Level (LOAEL) for dental fluorosis among children is 0.1 mg/kg body weight per day (WHO, 1984). Concerning skeletal fluorosis among adults, the WHO concluded that a daily intake of 14 mg/day is clearly harmful and that the first adverse effects may occur at 6 mg/day (WHO, 2002). The latter value will be adopted as the LOAEL for skeletal fluorosis in the present study.

Cases of endemic fluorosis have been reported from many regions worldwide, especially in East Africa, India and China where millions of people are affected. In East Africa (Rift Valley area) and India, it is mainly related to high F concentrations in natural groundwater, in conjunction with a high water intake (Choubisa, 1999, Reimann et al., 2003, Kloos and Tekle Haimanot, 1999, Srikanth et al., 2002). Sources other than drinking water can also contribute significantly to the prevalence of fluorosis as well. In China, for example, it is also related to indoor burning of F-rich coals and to the consumption of brick tea (Wang and Huang, 1995).

To date, the total daily F intake and the potential risks of skeletal fluorosis for residents in the Asembagus area have not been assessed. In this study, the total daily F intake by children and adults is quantified, and results are compared with the LOAEL values for dental and skeletal fluorosis established by the WHO. As there are considerable spatial variations in F concentrations in well waters, a fluorosis hazard map for the Asembagus area has been constructed, whereby the F intake via food, drinking water and surface water has been taken into account.

Section snippets

Site description

The Asembagus coastal plain is situated in the Situbondo district, in the north-eastern part of Java (Fig. 1). The study area of approximately 15×13 km encompasses the sub-districts of Asembagus, Banyuputih and Jangkar, and is here referred to as the ‘Asembagus area’ for convenience. The altitude of the area ranges between 140 m in the foothills of the Ijen volcanic complex to the south and sea level to the north. The water table is around 10–30 m depth and the soil is a volcanic ash soil.

Water

During the dry seasons of 1999 and 2000, 54 water wells were sampled, whereby some wells were visited twice to detect possible temporal fluctuations. A limited number of these wells were sampled again at the end of the rainy season of 2001 to allow comparison under different climatic conditions. Sample locations were selected to obtain representative data sets for wells both in areas irrigated with the contaminated water and in areas irrigated with other water sources. Between May 2000 and

Fluoride in well water

F concentrations in the well waters were in the range of <0.1 mg/l to 4.2 mg/l (Table 2). Of all the investigated wells, 37% contained <0.1 mg/l, 24% contained 0.3–1.4 mg/l and 39% contained more than 1.4 mg/l. The average pH of the well waters was 7.1±0.4. As can be seen in Fig. 2, the wells with the highest F concentrations were found close to the riverbed and within the area where the river water is used for irrigation. In some villages, the F concentrations varied from <0.1 to 2.5 mg/l

Discussion

Various cases of fluorosis due to high F concentrations in groundwater have been reported in volcanic areas (Kloos and Tekle Haimanot, 1999, Moturi et al., 2002). Of all active volcanoes, 12% contains an acid crater lake which are often rich in F, and effluent from these lakes may pose a hazard to the environment (Taran et al., 1998, Varekamp and Kreulen, 2000, Rowe et al., 1995, Pedrozo et al., 2001, Sriwana et al., 1998, Deely and Sheppard, 1996). In this study, we have estimated the total

Conclusion

At numerous locations in the Asembagus area, the total daily F intake exceeds the LOAEL not only for dental fluorosis, but also for skeletal fluorosis. Drinking water from local wells is the principal source of F and clearly prevails over the intake via locally produced foods. It is estimated that the lowest F concentration in drinking water that poses a risk is approximately 0.5 mg/l for dental fluorosis and 1.1 mg/l for skeletal fluorosis. These values are below the guideline value for safe

Acknowledgements

We are grateful to the government authorities and inhabitants of Asembagus, Banyuputih and Jangkar for generous support and warm hospitality, the Situbondo Irrigation Office, in particular Mr. Basuki, Mr. Djaelani and Mr. Sugiarto and the staff of the Asembagus branch for providing assistance and information, the Health Department of the Province of East Java for exchange of information Ansje Löhr, Thom Bogaard, Martin Hendriks, Inge Dewi, Mr. Kelik, staff members of UNIKA and The Netherlands

References (35)

  • C. Zevenbergen et al.

    A simple method for defluoridation of drinking water at village level by adsorption on Ando soil in Kenya

    Sci. Total Environ.

    (1996)
  • E.S. Budipramana et al.

    Dental fluorosis and caries prevalence in the fluorosis endemic area of Asembagus, Indonesia

    Int. J. Paediatr. Dent.

    (2002)
  • S.L. Choubisa

    Chronic fluoride intoxication (fluorosis) in tribes and their domestic animals

    Int. J. Environ. Stud.

    (1999)
  • S.L. Choubisa et al.

    Fluorosis in some tribal villages of Dungarpur district of Rajasthan, India

    Fluoride

    (1997)
  • R.W. Dabeka et al.

    Survey of lead, cadmium, fluoride, nickel and cobalt in food composites and estimation of dietary intakes of these elements by Canadians

    J.-Assoc. Off. Anal. Chem.

    (1995)
  • A. Kabata-Pendias et al.

    Trace elements in soils and plants

    (1984)
  • S. Kardjati et al.

    East Java nutrition studies: food consumption and nutritional status of mothers and preschool children in Sidoarjo and Sampang

    (1979)
  • Cited by (75)

    View all citing articles on Scopus
    View full text