Background
Significance of the research nationally and internationally based on actual EU Water policies.The management and use of water and water resources has been the focus of European Union (EU) water policy for many years. Regulations like the Nitrate Directive (91/676/EEC) or the Urban Waste Water Directive (91/14/EEC) to name only two were complemented and integrated latter on by the Water Frame Directive (2000/60/EC) which acted as an umbrella piece of legislation that embraced all the water Directives. These Directives targets the quality of water bodies with the aim of ensuring a sustainable use of water resources protecting the ecosystems and the human health. The necessity to define the quality of irrigation water has been recognized by WHO/ FAO and EFSA already many years ago. The WHO guidelines on the reuse of wastewater in agriculture have been published in a revised version in 2006 and will undergo a further revision during the next years. In the EU water abstraction data are collected regularly by Eurostat via the OECD/Eurostat Joint Questionnaire on Inland Waters. However, information on water abstraction for agricultural purposes is very incomplete if not inexistent (Wriedt et al. 2008). In the EU, agriculture is one of the three important water using sectors, besides industry and domestic users. In some Member States agricultural water consumption may represent up to 80% of the total water use. An EC Directive on irrigation water does not yet exist despite such waters may have an important impact on human health if the irrigated vegetables and fruits are contaminated with pathogenic microbes, but some European countries have national legislations and guidelines for the use of reclaimed waters.
The consumption of fruits and vegetables has significantly increased over the last decades. Considering only the sprout sector in Europe there are estimates that it has a turnover of about 150 – 200 m € for farms with a market value of 500 m € at the consumer level (EFSA). Fresh leafy vegetables, sprouts, fruits and other ready-to-eat vegetables can pose a serious health problem, if their production, harvesting, storage and distribution are not closely controlled. It had been estimated that foods of non-animal origin from 2008 to 2011 were responsible of 10% of the outbreaks, 26% of the outbreak cases, 35% of the hospitalizations and 46% of the deaths.
Another very important public health risk related to microbial pathogens in irrigation water is the increase in antibiotic resistant bacteria in patients and animals representing a threat to human health due to a lack of appropriate new antibiotics and it is consider that wastewater can act as a potential reservoir and transmission route for these bacteria. In fact in this environment horizontal gene transference of virulence and resistance genes can occur among bacteria, increasing their prevalence in the freshwater environments. Last but not least, the occurrence of cyanobacterial blooms can cause a significant water quality problem, especially as many species synthesize toxins which have an impact on the ecosystem (i.e. phytoplankton, benthic algae, plants, zooplankton, macro-invertebrates, fish, wading birds etc.) and on human health. Recently it has been demonstrated that human health symptoms thought to be caused by exposure to cyanobacteria during recreational use of water could also be associated with the heterotrophic bacteria like Aeromonas spp. associated with these cyanobateria (Berg et al., 2011).
Regulation (EC) 852/20044 on the hygiene of foodstuffs lays down general hygiene requirements to be respected by food businesses at all stages of the food chain, but there remain many gaps in the knowledge, especially in relation to the origin of the contamination during production from “farm to fork”. Contamination can occur at any stage of the production process, but a most crucial point is the quality of irrigation and production water. Microbiological problems have been addressed extensively in the 2006 WHO guidelines on the reuse of wastewater in agriculture but the fact that outbreaks continue increasing due to unsafe production of crops meant to be eaten raw and the paucity of national guidelines show that this topic should receive much more attention both from the scientific and regulatory perspectives.
Current guidelines for determining the microbiological quality of water used for irrigation mainly relay on the presence of coliform bacteria and E. coli. However, it is unclear how these indices correlate with the presence of specific human pathogens, and if they help to reduce the transmission of viruses, parasites and other emergent pathogens. Tools for the prevention of the microbiological contaminations of water are now based on the classical approach called Hazard Analysis and Critical Control Points (HACCP) used in the food production. They have been introduced by WHO in the Drinking Water production and are named the Water Safety Plans (WSP). This approach could also be applied as an important prevention tool to control the microbiological risk associated to the use of specific types of irrigation water as established in some European countries for the prevention of the Legionella infections.
