PULP MILLS (JUDGMENT) 92 ing of the actual performance of the plant in terms of the impact of its emissions on the river includes data obtained through different testing programmes conducted, inter alia, by an Argentine scientific team from two national universities, contracted by the National Secretariat of Environment and Sustainable Development of Argentina (ten sites), the OSE (Uruguay’s State Agency for Sanitary Works, from the Spanish acronym for “Obras Sanitarias del Estado”), DINAMA, independently of Botnia (16 sites), and Botnia, reporting to DINAMA and the IFC (four sites ; and testing the effluent). 233. The monitoring sites maintained by Argentina are located on the Argentine side of the river ; with the most upstream position located 10 km from the plant and the furthest downstream one at about 16 km from the plant. Nevertheless, three of the sites (U0, U2 and U3) are near the plant ; while another three are in Nandubaysal Bay and Inés Lagoon, the data from which, according to Argentina’s counsel, “enabled the scientists to clearly set the bay apart, as it acts as an ecosystem that is relatively detached from the Uruguay river” (Scientific and Technical Report, Chapter 3, appendix : “Background Biogeochemical Studies”, para. 4.1.2 ; see also ibid., para. 4.3.1.2). 234. The monitoring sites maintained by Uruguay (DINAMA) and by Botnia are located on the Uruguayan side. The OSE monitoring point is located at the drinking water supply intake pipe for Fray Bentos, at or near DINAMA station 11. 235. Argentina’s team gathered data from November 2007 until April 2009 with many of the results being obtained from October 2008. Uruguay, through DINAMA, has been carrying out its monitoring of the site since March 2006. Its most recent data cover the period up to June 2009. The OSE, in terms of its overall responsibility for Uruguayan water quality, has been gathering relevant data which has been used in the periodic reports on the operation of the plant. 236. The Court also has before it interpretations of the data provided by experts appointed by the Parties, and provided by the Parties themselves and their counsel. However, in assessing the probative value of the evidence placed before it, the Court will principally weigh and evaluate the data, rather than the conflicting interpretations given to it by the Parties or their experts and consultants, in order to determine whether Uruguay breached its obligations under Articles 36 and 41 of the 1975 Statute in authorizing the construction and operation of the Orion (Botnia) mill. 237. The particular parameters and substances that are subject to controversy between the Parties in terms of the impact of the discharges of effluent from the Orion (Botnia) mill on the quality of the waters of the 82