ter. Concentrations of pharmaceuticals in drinking-water are generally more than 1000-fold below the MTD, which is the lowest clinically active dosage. The findings from these three case-studies are in line with the evidence published over the past decade, which suggests that appreciable risks to health arising from exposure to trace levels of pharmaceuticals in drinking water are extremely unlikely.
Treatment technologies for removal of pharmaceuticals from drinking water established that raw sewage and wastewater effluents are a major source of pharmaceuticals found in surface waters and drinking-water, it is important to consider and characterize the efficiency of processes for the removal of pharmaceuticals during wastewater and drinking-water treatment. Most of the research has been conducted at the laboratory scale or at full scale in developed countries, including the USA, Japan, the Republic of Korea and countries in Europe. Even though wastewater and drinking-water treatment processes are not designed specifically to remove pharmaceuticals, they may do so to varying degrees. Pharmaceuticals are not unusual chemicals; their removal efficiencies during wastewater and drinking-water treatment are dependent on their physical and chemical properties. In cases where regulations require controls to mitigate risks from exposure to pesticides, treatment barriers may already be optimized to remove pharmaceuticals. Conventional wastewater treatment facilities generally have activated sludge processes or other forms of biological treatment such as biofiltration. These processes have demonstrated varying removal rates for pharmaceuticals, ranging from less than 20% to greater than 90%. The efficiency of these processes for the removal of pharmaceuticals varies within and between studies and is dependent on operational configuration of the wastewater treatment facility. Factors influencing removal include sludge age, activated sludge tank temperature and hydraulic retention time., Advanced wastewater treatment processes, such as reverse osmosis, ozonation and advanced oxidation technologies, can achieve higher removal rates for pharmaceuticals. Studies on conventional drinking-water treatment processes have shown that coagulation is largely ineffective in removing pharmaceuticals. Free chlorine is able to remove up to approximately 50% of the pharmaceuticals investigated, whereas chloramines have lower removal efficiency. Compounds that showed high removal by free chlorine but low removal by chloramines include antibiotics, such as sulfamethoxazole, trimethroprim and erythromycin. Advanced water treatment processes, such as ozonation, advanced oxidation, activated carbon and membranes (eg nanofiltration, reverse osmosis), are able to achieve higher removal rates (above 99%) for targeted pharmaceutical compounds in various studies in the published literature. Advanced and costly water treatment technology will not be able to completely remove all pharmaceuticals to concentrations less than the detection limits of the most sensitive analytical procedures at all times. Therefore, it is imperative that the toxicological relevance of various compounds be considered in the context of appreciable risks to human health. An informed risk assessment is essential before scarce resources are allocated to upgrade or invest in additional advanced treatment processes to reduce trace concentrations of pharmaceuticals in drinking-water.
Preventing pharmaceuticals in drinking-water drinking-water quality monitoring that focuses on end-product testing is resource intensive in terms of capital investment and human resources. Coupled with an expanding list of chemical contaminants in drinking-water and water sources that may be of insignificant health concern, an overemphasis on end-product monitoring and the upgrading of treatment infrastructure is not a sustainable, optimal use of limited resources.outlined in the WHO Guidelines for Drinking-water Quality, the water safety plan approach is the most effective means of consistently ensuring the safety of a drinking-water supply ... through the use of a comprehensive risk assessment and risk management approach that encompasses all steps in the water supply from catchment to consumer . Water safety plans highlight the importance of considering risk assessment and risk management comprehensively from source to tap and adopting preventive measures to address the source of risks.the water safety plan approach to the context of pharmaceuticals in drinking-water means that preventing pharmaceuticals from entering the water supply cycle during their production, consumption (ie excretion) and disposal is a pragmatic an...
