Health Risk Associated with Aluminium Exposure in Groundwater: A Cross-Sectional Study in an Orang Asli Village in Jenderam Hilir, Selangor, Malaysia
Last reviewed: March 2026
Key Findings
- Groundwater in the Orang Asli village of Jenderam Hilir was assessed for aluminium concentration and its potential health risk to indigenous residents.
- The study employed the US EPA health risk assessment framework to calculate the Hazard Index (HI) for aluminium ingestion through drinking water.
- Aluminium levels were compared against the Malaysian National Drinking Water Quality Standard threshold of 0.2 mg/L.
- Findings contributed to the growing body of evidence on environmental health disparities affecting Orang Asli communities in Malaysia.
Background and Context
Aluminium is the most abundant metallic element in the Earth’s crust, and its presence in groundwater is primarily driven by the natural weathering of aluminium-bearing minerals in soil and rock formations. While aluminium is generally considered to have low acute toxicity, chronic exposure through drinking water has been the subject of considerable scientific debate, particularly regarding its potential association with neurodegenerative conditions, most notably Alzheimer’s disease. Several epidemiological studies have suggested a positive correlation between elevated aluminium concentrations in drinking water and increased risk of cognitive decline, though this relationship remains contested in the broader scientific literature.
In Malaysia, surface water from major river systems — including the Langat, Selangor, and Kinta rivers — constitutes the primary source of public drinking water supply in Peninsular Malaysia’s west coast states. However, in rural and remote areas, particularly those inhabited by Orang Asli (indigenous) communities, residents often depend on untreated groundwater from wells, gravity feed systems, or direct river abstraction. These alternative water sources typically lack the treatment infrastructure available in urban areas, potentially exposing communities to elevated levels of naturally occurring contaminants including aluminium, iron, and manganese.
The Orang Asli represent Malaysia’s indigenous minority, comprising approximately 0.6% of the national population. Distributed across 18 ethnic sub-groups within three main categories — Negrito, Senoi, and Proto-Malay — these communities have historically experienced significant health disparities compared to the broader Malaysian population. Studies have documented higher rates of malnutrition, infectious diseases, and limited access to healthcare services among the Orang Asli. Environmental health concerns, particularly those related to water quality, represent an additional dimension of these disparities that has received comparatively less research attention.
The village of Jenderam Hilir is situated in the Dengkil area of the Sepang District, Selangor, along the Langat River basin. The area is characterised by alluvial deposits overlying older geological formations, creating hydrogeological conditions that can influence the chemical composition of groundwater. Previous hydrogeological studies conducted at the Jenderam Hilir site, particularly those investigating river bank filtration as a water treatment approach, have documented the complex interactions between surface water and groundwater quality in the area, noting that aluminium concentrations in the Langat River have been recorded at levels exceeding the Malaysian drinking water quality standard of 0.2 mg/L.
Study Design and Methodology
This study employed a cross-sectional design to assess the health risk associated with aluminium exposure through groundwater consumption among residents of the Orang Asli village in Jenderam Hilir. Groundwater samples were collected from community wells used by residents as their primary drinking water source. The aluminium concentrations in collected water samples were determined using analytical methods appropriate for trace metal quantification.
The health risk assessment followed the methodology established by the United States Environmental Protection Agency (US EPA), which provides a standardised framework for evaluating the potential health effects of environmental contaminant exposure. The assessment calculated the Chronic Daily Intake (CDI) of aluminium through the oral ingestion pathway, taking into account exposure parameters including the contaminant concentration in water, daily water ingestion rate, body weight, and exposure frequency and duration. The Hazard Index (HI) was then calculated by dividing the CDI by the established Reference Dose (RfD) for aluminium, which represents the threshold below which daily exposure is unlikely to pose appreciable health risk over a lifetime.
A Hazard Index value less than 1 is generally interpreted as indicating that the exposed population is unlikely to experience adverse health effects from the contaminant at the measured concentration, while a value exceeding 1 suggests potential health risk warranting further investigation or mitigation measures. This methodology is widely used in environmental health assessments globally and has been applied in similar studies of drinking water quality in rural Malaysian communities.
Key Results and Implications
The study assessed aluminium concentrations in groundwater samples from the Orang Asli village and evaluated the associated health risk through the US EPA framework. The analysis provided insights into whether the indigenous community’s reliance on groundwater as a drinking water source presented measurable health risks related to aluminium exposure. The study’s citation record indicates it has been referenced by subsequent research on aluminium in Malaysian drinking water, including a 2019 study published in Exposure and Health that described it as contributing to the understanding of aluminium health risks in groundwater contexts in Malaysia.
The broader significance of this research lies in its contribution to understanding environmental health vulnerabilities among Malaysia’s indigenous communities. The Orang Asli of Peninsular Malaysia have experienced rapid environmental and social changes in recent decades, including deforestation, land development, and increased integration with the broader Malaysian economy. These changes have altered traditional water sourcing patterns and potentially introduced new environmental health exposures. Research documenting the specific contaminant profiles of water sources used by indigenous communities is essential for developing targeted public health interventions.
Contextual Data on Aluminium in Malaysian Drinking Water
| Parameter | Details |
|---|---|
| Malaysian NDWQS limit for aluminium | 0.2 mg/L |
| WHO guideline value for aluminium | 0.2 mg/L (aesthetic-based) |
| Mean aluminium in Langat River (2015-2016) | 0.25 ± 0.19 mg/L (exceeds NDWQS) |
| Primary source of aluminium in groundwater | Natural weathering of aluminium-bearing minerals |
| US EPA oral Reference Dose for aluminium | 1.0 mg/kg/day |
Implications for Public Health Policy
The findings from this study carry several implications for environmental health policy in Malaysia. First, they underscore the need for systematic water quality monitoring in Orang Asli settlements, many of which rely on untreated or minimally treated water sources. The Malaysian government, through the Department of Orang Asli Development (JAKOA), has implemented various infrastructure improvement programmes in indigenous villages, including the provision of treated water supply. However, coverage remains incomplete, and many remote communities continue to depend on traditional water sources.
Second, the study contributes to the evidence base for prioritising gravity feed systems and community well programmes in Orang Asli villages, with appropriate treatment to address naturally occurring contaminants. The relative effectiveness of different water treatment technologies for aluminium removal in rural contexts — including coagulation-flocculation, filtration, and river bank filtration — represents an important area for applied research and policy development.
Third, the study’s application of the US EPA health risk assessment framework demonstrates the utility of this standardised methodology for evaluating environmental health risks in Malaysian contexts. Subsequent studies have adopted similar approaches to assess contaminant exposure in other rural communities, including assessments of nitrate and heavy metal concentrations in gravity feed system water used by Orang Asli populations.
Limitations
Cross-sectional study designs provide a snapshot of conditions at a single point in time and cannot capture seasonal or temporal variations in groundwater chemistry. Aluminium concentrations in groundwater can fluctuate significantly with changes in rainfall patterns, soil conditions, and aquifer recharge dynamics. Additionally, health risk assessments based on the US EPA framework rely on standardised exposure parameters that may not precisely reflect the actual water consumption patterns and body weights of the study population. The study focused specifically on the ingestion pathway for aluminium exposure, while dietary intake from food sources — which typically represents the largest source of total aluminium exposure — was not assessed. Finally, the study’s focus on a single village limits the generalisability of findings to other Orang Asli communities, which occupy diverse environmental and hydrogeological settings across Peninsular Malaysia.
Content shared under CC BY-NC 4.0 licence. © Malaysian Journal of Public Health Medicine.