Question: when did flint michigan's water become contaminated
[{'answer': '2014', 'provenance': [{'wikipedia_id': '48953764', 'title': 'Flint water crisis', 'start_paragraph_id': 1, 'start_character': 32, 'end_paragraph_id': 1, 'end_character': 36, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]