Microplastics and their possible sources: The example of Ofanto river in southeast Italy * Claudia Campanale a, * , Friederike Stock b , Carmine Massarelli a , Christian Kochleus b , Giuseppe Bagnuolo a , Georg Reifferscheid b , Vito Felice Uricchio a a Water Research Institute-Italian National Research Council, Italy b Department of Biochemistry, and Ecotoxicology, German Federal Institute of Hydrology, Koblenz, Germany article info Article history: Received 28 May 2019 Received in revised form 27 August 2019 Accepted 19 September 2019 Available online xxx Keywords: Microplastics Water samples Ofanto river Italy Monitoring Agriculture abstract Monitoring studies have quantified microscopic plastic debris, so-called microplastics, in freshwater systems, including banks, surface waters and sediments. However, there is a lack of knowledge of freshwater and terrestrial environments. When microplastics are released in freshwater environments, they will be transported and will not remain stationary. Moreover, their transport from sink to source (land-based to river systems) may depend on several factors such as weather conditions and river hydrology. The present study aims to investigate the abundance and composition of microplastics in the most important river of Apulia Region (Southeast Italy) evaluating the main drivers and possible input sources of microplastic debris. The following work is the first study showing an Italian river context. For this research five sampling campaigns have been conducted west of the Ofanto river mouth. Microplastics were collected by three surface plankton nets fixed in the middle of the river in order to reduce the spatial and temporal variability. For each campaign, a total of six replicates were sampled during two time slots. Microplastic concentrations ranged from 0.9 ± 0.4 p/m 3 to 13 ± 5 p/m 3 showing comparable values to or greater than those ones reported in other studies. A statistically significant difference in the average microplastic concentrations in different campaigns of this study has been observed, suggesting thus a temporal variation in plastic abundances. These significant differences could be explained by the hy- drology of the river that influences the particle concentration with its physical forces such as flow ve- locity, water level and seasonal variability. Microplastics were found at higher concentrations during wet periods indicating a land-based origin probably connected to waste produced by the surroundings agricultural areas. In fact, Spearman's correlation results show a strong positive statistically significant correlation between the concentration of microplastics and the water level (R ¼ 0.8475, p < 0.0001). © 2019 Elsevier Ltd. All rights reserved. 1. Introduction Macro- and microplastics (MP) have been investigated a lot in the last years, starting with the marine environment in the 1970s (Carpenter and Smith, 1972; Carpenter et al., 1972; Cole et al., 2011; Koelmans et al., 2014; Suaria et al., 2016; Campanale et al., 2019). Researchers investigated freshwater environments also, especially in these recent years (Baldwin et al., 2016; Eerkes-Medrano et al., 2015; Mani et al., 2015; Wagner and Lambert, 2018). First data of microplastic concentrations in rivers were published e.g. for the European rivers Rhine (Klein et al., 2015; Heb et al., 2018; Mani et al., 2019), Danube (Hohenblum et al., 2015), Seine (Dris et al., 2015) and Thames (Horton et al., 2017) and worldwide such as for the rivers Los Angeles (Moore et al., 2011), Yangtze and Hanjiang (Wang et al., 2017) Atoyac (Mexico) (Shruti et al., 2019) as well as for rivers on the Tibetan plateau (Jiang et al., 2019). In Italy, Fisher et al. (2016) analysed the microplastic pollution in central Italy lakes, Sighicelli et al. (2018) in subalpine lakes and Atwood et al. (2019) on the beaches in the environs of the Po river estuary. However, no paper has been published about the microplastic concentration of Italian rivers. Although many papers are available, * This Paper has been recommended for acceptance by Lei Wang. * Corresponding author. E-mail address: claudia.campanale@ba.irsa.cnr.it (C. Campanale). Contents lists available at ScienceDirect Environmental Pollution journal homepage: www.elsevier.com/locate/envpol https://doi.org/10.1016/j.envpol.2019.113284 0269-7491/© 2019 Elsevier Ltd. All rights reserved. Environmental Pollution xxx (xxxx) xxx Please cite this article as: Campanale, C et al., Microplastics and their possible sources: The example of Ofanto river in southeast Italy, Environmental Pollution, https://doi.org/10.1016/j.envpol.2019.113284