Emerging pollutants
A particularly challenging type of compounds addressed during the week was the occurrence, fate and accumulation of emerging pollutants in water and wastewater, and their impact on human health and ecosystems. The development and production of new chemical compounds is so fast that yesterday’s leading edge is today’s household item. Several of the compounds listed under the previous heading could also fit under this, as little is known of their impacts on us and on our surroundings. They comprise a wide variety of complex chemicals that can cause severe biotic damage at low concentrations, threatening the functions of life. They include both industrial additives, surfactants, pesticides, “wonder drugs”, pharmaceuticals and endocrine disruptors. These pollutants appear both in effluents from treatment plants, in drainage from agricultural land and settlements, and in leakages from septic tanks as well as landfills with their piles of corroding consumer products. Some pollutants are resistant to decay and do not vanish even if banned. Others split during degradation into even more dangerous substances. Early omens of effects have been reported since the 1950’s in terms of health disturbances of living organisms in air, on landand in water. Concern has been growing with time over the increasing effects also on humans in terms of organ disorders,fertility and neurological disturbances, even suggesting transgenerational effects. Numerous cases of appearance in rivers, in raw water sources, in wastewater and sewer outflows were reported during the discussions, including the fate of emerging pollutants in a case of large scale wastewater reuse. Not only the widespread use of human drugs but also of veterinary drugs caused increasing concern. The concern deepens when realising that medicine use is increasing in a world with growing populations and growing cohorts of elderly people. It was suggested that known endocrine disruptors probably only represent the top if an iceberg. Discussions highlighted both biological effects on living species and the problems met in wastewater treatment where pharmaceuticals escape removal unless adding extremely costly steps for their elimination. The poor understanding of the biological and chemical degradation in the natural environment was seen as highly disturbing. One message emerging from the discussions was the strong need for research to generate better understanding of environmental degradation and transformation products. Long term effects on humans and other living creatures have to be analysed and proper strategies for waste disposal be developed. When it comes to pharmaceuticals, it was suggested that prescription lists8 Photo: Jupiterimages of less damaging pharmaceuticals might be an alternative approach to introduction of complex concentration thresholds. It was concluded that emerging pollutants are raising extreme technical challenges. One issue of special relevance for the water community is the implications for increased waste water reuse. Another relates to the growing hope currently paid to productive sanitation for reuse of nutrients as a win-win solution notably in developing countries with poor soil fertility, and the potential advantages or disadvantages of such practise. The implications of expanding reuse of urine have therefore to be analysed in view of its content of emerging pollutants and the fact that some may be absorbed by plants when irrigating. It was however suggested that putting urine in the soil is a better solution than conventional disposal into water systems, generating problems for aquatic systems especially fish. In summary, emerging pollutants are already permeating the world and threatening functions of life, including disruptions of fertility, both male and female in humans as well as in other living organisms. Research is essential to develop the knowledge needed as a base for sound policy development. The proposed remedies ranged from banning to source separation and regulations including threshold values. It is important that the effects of all current and future consequences arising from the use of any new chemicals are carefully taken into account. As always is it paramount that one use of water does not render other uses and reuse impossible.
