Agriculture, Ecosystems and Environment 181 (2013) 50–57 Contents lists available at ScienceDirect Agriculture, Ecosystems and Environment jo ur nal home p age: www.elsevier.com/locate/agee Microbial impact of different types of municipal wastewaters used to irrigate nectarines in Southern Italy Gaetano Alessandro Vivaldi ∗ , Salvatore Camposeo, Pietro Rubino, Antonio Lonigro Dipartimento di Scienze Agro-Ambientali e Territoriali, Università degli Studi di Bari Aldo Moro, Via Amendola 165/A, 70126 Bari, Italy a r t i c l e i n f o Article history: Received 21 March 2013 Received in revised form 27 August 2013 Accepted 3 September 2013 Keywords: Prunus persica (L.) Batsch Fecal indicators Fruit contamination Water recycling Tertiary treatment a b s t r a c t This research was performed in order to assess the microbiological impact of three different sources of treated municipal wastewater on the tree-soil system of a nectarine orchard. Wastewaters coming from two different tertiary treatment processes [conventional tertiary water (TW) and lagoon simplified tertiary water (LW)] and a secondary treatment process (SW) were compared with fresh water (FW). A two-year field experiment (2011 and 2012) was carried out monitoring Total Coliforms, Fecal Coliforms, E. coli and Salmonella spp. concentrations on source waters, root zone soil and fruits. The microbial con- centration mainly depended on the treatment system of the source water but in most cases it was always over the current Italian threshold (10 CFU 100 mL -1 ; D. No. 152/2006). In general, the SW showed the highest level of contamination for both years followed by LW, TW and FW. Although soil plots irrigated with the SW were heavily contaminated as expected, nevertheless the soil was able to greatly reduce of 2.6 log 10 CFU 100 g -1 the fecal contamination. The soils irrigated with LW, TW and FW showed a lower fecal bacteria contamination. Total Coliforms were confirmed as ubiquitous in this agricultural environ- ment and contamination by E. coli on fruits surfaces was not negligible when plots were irrigated with SW for both years. This study supports the hypothesis that very low quality of irrigation waters cannot be used safely in a nectarine orchard because it represents a risk for human infection. © 2013 Elsevier B.V. All rights reserved. 1. Introduction By 2050, food production is projected to increase by about 70% globally and nearly 100% in developing countries (FAO, 2011). This increased demand for food will place unprecedented pressure on many agricultural production systems across the world, increas- ing the water demand for agriculture. As such wastewater reuse will need to provide more water for irrigated areas and to make available water in dry areas (Angelakis et al., 1999). A large number of studies (Bastos and Mara, 1995; El Hamouri et al., 1996; Lopez et al., 2006, 2010; Ndiaye et al., 2011; Palese et al., 2009; Petterson et al., 2011; Pollice et al., 2004) have shown that microbiological contamination remains a crucial issue to insure the safe use of municipal wastewater in agriculture. The risk is rep- resented by a many kinds of microorganisms, including viruses, bacteria and pathogenic protozoan/helminthes; the bacteria are the most common of the microbial pathogens found in recycled Abbreviations: FW, fresh water; TW, conventional tertiary water; LW, lagoon simplified tertiary water; SW, secondary water. ∗ Corresponding author. Tel.: +39 080 5442982; fax: +39 080 5442982. E-mail addresses: gaetano.vivaldi@uniba.it (G.A. Vivaldi), salvatore.camposeo@uniba.it (S. Camposeo), pietro.rubino@agr.uniba.it (P. Rubino), antonio.lonigro@uniba.it (A. Lonigro). waters (Toze, 1997,1999). To break down or otherwise reduce the contamination of the municipal wastewater and then minimize the risk of crops contamination, high-technology tertiary treat- ments and disinfection systems, such as activated carbon, reverse osmosis, membrane filtration, chlorination, ozonation, UV irradia- tion (Asano and Levine, 1998) and tertiary lagoons (or maturation ponds) are essential to insure microbial populations remain below critical levels. The latter process has generally been viewed as an effective, low-cost method of removing pathogens from wastewa- ter (Maynard et al., 1999), while the other treatment systems are often prohibitively expensive, particularly in developing Countries, where only about 10% of wastewater undergoes treatment of any kind (Homsi, 2000). The low operation and maintenance costs of tertiary lagoons, coupled with the effective percentage pathogen removed reported in literature (Pearson et al., 1987a,b; Mara and Pearson, 1987; Mara et al., 1992a,b), have made them a popular choice for wastewater treatment in such economically stressed areas (Maynard et al., 1999). Different legislative approaches are used in the world to deter- mine the level of contamination of the wastewater that can be used in agriculture. The WHO guidelines (Blumenthal et al., 2000), using empirical epidemiological evidence, classified the reuse in three category: Category A – “unrestricted irrigation” recommended the level of Fecal Coliforms less than 1.000 CFU 100 mL -1 , usable for vegetable and salad crops eaten uncooked, sport fields and 0167-8809/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.agee.2013.09.006