Health Risk and Health Impact Assessments (HRIAs)

The risk-based approach to environmental health management is still not-well known in. We conducted research to generate evidence of how risk assessments can be used for specific cases of environmental related issues such as dioxin contamination in the environment and Arsenic contaminated drinking water. In addition, there is a clear need for Health Impact Assessments (HIA) in South East Asia where many large infrastructure development projects, i.e., dam construction, mining industries, and agricultural production are taking place and where HIA capacity is lacking. Therefore, through research and training with partners we will build capacity and expertise in HIA in the region.

Risk assessment of chemical contaminants in the environment: Dioxin hot spots and Arsenic in drinking water

We applied the Australian Environmental Health Risk Assessment Framework to assess the risk of dioxin exposure through the foods of local residents living in dioxin hot spots, i.e., the seven wards surrounding the airbases in Bien Hoa and Da Nang cities. These wards served as bulk storage and supply facilities of Agent Orange and other herbicides during the Vietnam War and are currently considered as dioxin hot spots in Vietnam. Various stakeholders were involved in the risk assessment process and the related publications on dioxin characteristics, its toxicity, and its levels in local soil, mud, food, milk, and blood samples. A food frequency and knowledge-attitude-practice survey of 1000 randomly selected local households, together with food sampling and analysis for dioxin/furan concentrations, were undertaken to provide data for exposure assessment. Results showed that local residents who consumed local high risk foods, especially freshwater fish, snails, crabs, free range chicken meat and eggs, duck meat and eggs, beef and buffalo meat, pumpkin, and lotus caught/raised/harvested inside or in the surroundings of  the airbases were at very high risk. Their dioxin daily intake levels exceeded the recommended tolerable daily intake level recommended by WHO (1-4 pg/kg/day). Followed this risk assessment, a multi-approach risk reduction program was developed and implemented by the Vietnam Public Health Association and its provincial branches in Bien Hoa and Da Nang during 2007-2009 and 2009-2011 to reduce the risks of dioxin exposure to local residents. Risk communication activities should be integrated into local routine health promotion programs in order to continue reducing the risks to the local residents from dioxin in the upcoming years.

The issue of health impact due to arsenic (As) contamination of drinking water is a great public health challenge. According to UNICEF, there are approximately 10-15 million people in Vietnam at risk of arsenic poisoning due to consuming tube-well water. We applied an environmental health risk assessment approach to analyze the arsenic contamination in tube-well water and to assess the health risks of people in the ChuyenNgoai Commune, Duy Tien District, Ha Nam Province. A total of 150 households were included in the study; water and hair samples were taken and drinking water consumption characteristics were surveyed. Cancer risks were calculated, using the Cancer Slope Factor (CFS) for arsenic and the estimated daily dose. Results showed that arsenic concentration in tube-well water ranged from 8–579 ppb (mean 301 ppb) before filtration and that the sand filters currently used by the households did not meet the standard for As removal. The arsenic daily consumption of 40% of the adults exceeded the TDI level (Tolerable Daily Intake) of 1 µg/kg/day. The average skin cancer risk in adults due to consuming filtered tube-well water for drinking purposes was 25.3 × 10⁻⁵ (using only well water) and 7.6 × 10⁻⁵ (using both well and rain water). The skin cancer risk would be 11.5 times higher if the water was not filtered. Improving filtration measures or replacing the current drinking water sources is urgently needed to minimize the health risks to the local population.

Health Impact Assessment

CENPHERs first experience in HIA was its participation in a collaborative project entitled: “Resource Recovery Reuse (RRR)” with Swiss TPH. Swiss TPH and CENPHER jointly conducted health risk and impact assessments (HRIAs) along the waste management and wastewater chains in Hanoi. The research consists of four parts: 1) a cross-sectional study with 1000 participants to assess the existing exposure risks due to wastewater in different exposure groups with a specific focus on parasitic infections, skin diseases, eye diseases, and diarrhoeal episodes. The survey comprises of two components: (i) a questionnaire study; and (ii) the collection of stool samples to determine the prevalence and the intensity of helminth and of intestinal protozoa infections; 2) a pathogen flow analysis to observe the variance of pathogen contamination at critical control points over two months. Over a two month period, we will analyze wastewater for microbial contamination from bacteria (total faecal coliform, E. Coli, Salmonellaspp.,including antibiotic resistance testing of the 10 most commonly used antibiotics in Vietnam), helminth eggs and physiochemical factors (pH, rainfall); 3) quantitative microbial risk (QMRA) assessment interlinked to pathogen flow analysis to estimate diarrhoeal and parasitic infection risks of exposure groups and validate the results with the findings obtained under objective 1.