What the outlet published · Sentence 2
“[L]a analítica que dio positiva por contaminación fecal el pasado 22 de junio, víspera de San Juan, con una gran fiesta prevista en esa zona.”
Translation · ES
[T]he test that came back positive for faecal contamination on 22 June, the eve of San Juan, with a large festival planned in that area.
What this claims, in our words
THE TRIGGER: a positive faecal contamination reading on 22 June, the day before a mass beach festival. The date and the result are on a laboratory record.