Nationwide SARS-CoV-2 Surveillance Study for Sewage and Sludges of Wastewater Treatment Plants in Turkey

1.Since the announcement of the pandemic of Covid-19 by WHO on March 11, 2020, the countries have started to monitor surveillance of SARS-CoV-2 through medical tests. However, people with no and very light symptoms are usually not medically tested or never hospitalized and they are missed. In the study of Wu et al. [1], it was realized that the urine and faeces of all infected people contain SARS-CoV-2. After that, sewage, and sludge-based SARS-CoV-2 surveillance studies have gained significant importance around the world (Fig.1). SARS-CoV-2 was detected in wastewaters in The Netherlands [2,3,4], USA [1,5,6,7, 8, 9, 10], Australia [11], France [12, 13, 14], China [15], Spain [16,17,18,19,20], Italy [21, 22,23], Israel [24], Turkey[25], Germany[26], Japan [27,28], India [29,30], Pakistan [31], Brazil [32,33], Chile [34], Denmark, France, Belgium[35], Equator [36] and Sweden [37] using different virus concentration techniques. Published data show that high concentrations of the SARS-CoV-2 RNA reaches to wastewater treatment plants (WWTPs). On 7th of May 2020, Turkey took its place among a few country which have been started wastewater based surveillance studies at the early stages of pandemic by reporting SARS-CoV-2 RT-qPCR levels of major WWTPs of Istanbul [25]. Turkey [38] first detected SARS-CoV-2 in both primary and waste activated sludges of Istanbul WWTPs. Later, USA [39] and Spain [40] were also studied on sludge samples. There are also studies evaluating the SARS-CoV-2 in WWTPs effluents [10,13,14, 28, 29,30, 34, 36]. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/20240549v1_fig1.gif" ALT="Figure 1"> View larger version (59K): org.highwire.dtl.DTLVardef@ba8798org.highwire.dtl.DTLVardef@1c3cbeorg.highwire.dtl.DTLVardef@1d7f284org.highwire.dtl.DTLVardef@72e423_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig 1.C_FLOATNO Worldwide SARS-CoV-2 surveillance studies in wastewater (https://www.google.com/maps/) C_FIG This study aimed to scan distribution of Covid-19 through Turkey by SARS-CoV-2 measurements in influent, effluent and sludge samples of WWTPs. The influent, effluent and sludge samples were collected from main WWTPs located in 81 cities of Turkey through May 2020-July 2020. Among those 81 cities, Istanbul metropole with 15.5 million inhabitants was chosen as the pilot city since 65% of all cases in Turkey were present here. Hence, all treatment plants in Istanbul were scanned through the study. The viral activity tests were also conducted for the influent, effluent and sludge samples resulting high qPCR.