Table 2.

SARS-CoV-2 detection in sewage samples, October 2019 – February 2020.

Sample ID	Origin	Date of sampling	WWTP	Nested RT-PCR	Real-time RT-(q)PCR (c.g./L)
3285	Milan	24/10/2019	A	−	−
3287	Milan	25/11/2019	A	−	−
3289	Milan	18/12/2019	A	+	4.1 × 103
3290	Milan	18/12/2019	A2	−	8.7 × 102
3238	Milan	20/12/2019	B	+	1.2 × 103
3291	Milan	29/01/2020	A	+	2.3 × 103
3292	Milan	29/01/2020	A2	−	2.2 × 103
3244	Milan	03/02/2020	B	−	6.1 × 102
3231	Milan	12/02/2020	A	−	1.6 × 103
3239	Milan	12/02/2020	B	−	2.8 × 103
3232	Milan	19/02/2020	A	+	−
3240	Milan	19/02/2020	B	−	2.6 × 103
3241	Milan	23/02/2020	B	+	1.5 × 103
3233 ⁎	Milan	24/02/2020	A	+	9.2 × 102
3230	Milan	25/02/2020	A	+	4.8 × 102
3237	Milan	25/02/2020	A2	−	1.4 × 103
3234	Milan	26/02/2020	A	+	3.7 × 103
3242	Milan	26/02/2020	B	−	1.7 × 103
3235	Milan	28/02/2020	A	−	−
3243 ⁎	Milan	28/02/2020	B	+	1.3 × 103
3144	Turin	09/10/2019	C	−	−
3145	Turin	09/10/2019	C	−	−
3321	Turin	06/11/2019	C	−	−
3323	Turin	06/11/2019	D	−	−
3325	Turin	20/11/2019	C	−	−
3329	Turin	04/12/2019	C	−	−
3331	Turin	04/12/2019	D	−	−
3333	Turin	18/12/2019	C	+	−
3335	Turin	18/12/2019	D	+	1.2 × 103
3337	Turin	14/01/2020	C	+	7.4 × 102
3339	Turin	15/01/2020	D	+	1.2 × 103
3341	Turin	28/01/2020	D	+	5.6 × 102
3343	Turin	29/01/2020	C	−	6.0 × 102
3345	Turin	11/02/2020	D	−	4.7 × 102
3347	Turin	25/02/2020	D	+	2.9 × 102
3349	Turin	26/02/2020	C	+	5.6 × 104
3374	Bologna	21/11/2019	E	−	−
3375	Bologna	10/12/2019	E	−	2.9 × 104
3376	Bologna	29/01/2020	E	+	3.3 × 104
3377	Bologna	19/02/2020	E	+	−

Highlighted in bold are the first occurrences of SARS-CoV-2 in each of the urban areas included in the study. ‘A2’ represents a second branch of the ‘A' wastewater treatment plant. Samples below 5.9 × 10³ g.c./L (LOQ) should be considered as estimated counts.

^⁎Samples detected as positive in a previous study (La Rosa et al., 2020) and confirmed as such by repeating both the extraction and the molecular analysis.