The project looked to establish, in conjunction with Dinas Lingkungan Hidup Jatim (DLH Jatim) – the Environmental Management Agency of East Java – a new bio-assay method for first-pass evaluation of the chemical toxicity of water. Three cases studies were considered:
- Changes in water toxicity as a result of human centric discharges to the Brantas River in East Java.
- The quality of reticulated water in the City of Surabaya.
- The quality of a range of bottled water products.
The results were compared to water supply, wetland, wastewater discharge and reticulated water samples in Melbourne, Australia. This was the first time an alternative to chemical analytical approaches had been utilised in Indonesia for the evaluation of water quality in terms of the presence of chemicals that may lead to acute or chronic toxicity to humans and the environment. Rivers and the associated environs in East Java are highly polluted as a result of inadequate wastewater treatment management.
DLH Jatim is cost and capability constrained in terms of chemical analytics. The chemical as distinct from pathogenic safety of reticulated water is also unclear. The methodology that was established provides a cheap and relatively low-tech first-pass or hurdle assessment of the potential for acute or chronic chemical toxicity of discharges to the environment and of water for human consumption (both cooking and drinking). Previous studies have shown that there is a direct correlation between the chemical toxicity of more than 3000 chemical compounds and the bioluminescence response of a simple marine photobacterium (Vibrio fisheri). The adapted methods allowed a higher-order regulatory framework to be established for discharges and provided feedback as to the adequacy of current water treatment approaches for reticulated water supply, with the use of expensive chemical analytics being an important but second-order consideration.
The project aimed to:
- Establish a laboratory for the screening of water samples from a range of sources, including waste water, industrial discharge, rivers and water allocated for potable use.
- Develop a field program of screening of river health that is consistent with EPA guidelines in the US and Australia but without the need for in-depth analysis that looks to identify the actual toxins being discharged.
- Train personnel from ITS in more detailed bio-assay and eco-toxicological methods.
- Move to a philosophy where bio-assay rather than chemical analytics is used for secondary source identification rather than routine chemical water analysis.
- Use the information from routine assays of river and potable water to inform a new regulatory environment and to inform choices of infrastructure for water and wastewater treatment.
The methodology established through previous work and further elaborated in this work showed that for a water samples to be considered chemically non-toxic for drinking purposes, a concentration point of >400 is required whereby a reduction in photobacterium response of <50 per cent (LC50) is observed. A previous study demonstrated that, for water samples meeting the Australian drinking water standard in terms of chemical analysis across 1200 chemicals and showing no response to receptor specific bioassay, a LC50 of more than 400 was always observed. A qualitative overview of the results of the testing showed:
- Longitudinal sampling of the Brantas River for over 200 kilometres showed that, even in the upper reaches of the river, the LC50 of all water samples was <10 or at least 20 times more toxic than is deemed highly suitable for drinking water purposes. Some samples were so nutrient rich as to cause an increase in photobacterium response at short time scales (5 minutes). They were observed to be acutely toxic at longer time scales (10 minutes).
- Sampling and analysis of water samples from the Surabaya reticulated water system in one district, from close to the water treatment plant and then at various points in the system, showed highly variable results, including values of LC50 from <20 and up to 150. None of the samples, by this analysis, would be considered safe for human consumption, even after boiling. The data suggests a highly porous distribution network.
- Analysis of a range of bottled water samples showed a LC50 of >100 in all cases whereby there was no response at this concentration ratio, indicating that they were most likely safe to drink.
Results and achievements
Simple toxicity testing using bioassay was able to demonstrate a longitudinal increase in chemical toxicity down the Brantas River using a low-cost methodology. The data was consistent with and correlated with COD measurements. The water in the lower reaches of the river was observed to be acutely toxic. This provides the basis for the assessment of discharges into the river without the use or need for expensive laboratory methods (as a first-pass hurdle assessment). In addition, the inadequacy of the treatment process for water from the Brantas River that is then distributed into the water reticulation system of Surabaya was clearly demonstrated. Many samples in the distribution system were observed to be chronically chemically toxic. This is a major indicator for planning of future treatment infrastructure and is contrary to current beliefs as to the safety of the water in the reticulation system and the adequacy of the treatment process. This is a typical misconception that deems water to be safe if it can be shown to be free of pathogens. The water in the reticulation system was shown in some locations to be more chemically toxic than secondary treated effluent from a wastewater treatment plant in Melbourne, Australia. This is disturbing but perhaps not surprising given that the feed to the treatment process is in the lower reaches of the river and almost 20 million people inhabit the basin, with limited waste water treatment. The use of standard treatment processes for the production of water for human consumption from a highly contaminated feed source was shown to be highly inadequate.