Runoff from firework manufacturing as major perchlorate source in the surface waters around Diwali in Ahmedabad, India

Fireworks events during the annual Indian festival of Diwali has been heavily criticised in recent times. Perchlorate is an essential component of fireworks. The effects of the fireworks on perchlorate (ClO<inf>4</inf>⁻) concentrations and quality parameters of the ambient waters of Ahmedabad, Gujarat, India were studied. As expected, ClO<inf>4</inf>⁻ concentrations in the (Kankaria) lake adjoining the fireworks site were below detection prior to the Diwali event and increased to 0.97 and 1.03 μg/L at 48 and 288 h after the event, respectively. However, samples from the Sabarmati River surprisingly contained an extremely high concentration of ClO<inf>4</inf>⁻ (65 μg/L) one day before the event, which decreased to 1.14 μg/L after 48 h and was below detection limit after 7 days of the event. This finding raises questions such as: (a) which has greater impact, fireworks manufacturing or burning; (b) can unregulated release of untreated effluents be a major critical source of pollution needing immediate attention from removal, environmental regulation and policy perspectives; c) is policy pertaining to unskilled labour in the manufacturing of fireworks and other ClO<inf>4</inf>⁻-containing products needed in developing countries; and d) is ClO<inf>4</inf>⁻ being a strong oxidiser, detrimental to the soil, groundwater, and aquatic environment?