Abdul Wahab Khan
Panaji
A water quality assessment conducted by Goa State Pollution Control Board (GSPCB) after the 2024 Ganesh Chaturthi visarjan recorded significant levels of heavy metals across immersion sites. The study covered 12 rivers and lakes between August 23 and September 23, 2024, with samples collected before immersions and on the 3rd, 5th, 7th, 9th, and 15th days after immersions.
Analysis for 11 metals – cadmium, cobalt, copper, chromium, manganese, lead, zinc, mercury, antimony, barium, and strontium – revealed contamination linked to idol materials, particularly paints, Plaster of Paris, and decorative substances.
At Baina Beach, strontium peaked at 4.929 mg/l on the 7th day, alongside zinc (0.222 mg/l) and manganese (0.139 mg/l). Chromium was also detected post-visarjan, with 0.139 mg/l on day 7 and 0.025 mg/l on day 15.
At River Mandovi ferry wharf, lead rose from 0.03 mg/l pre-immersion to 0.06 mg/l by the 7th day, while manganese jumped from 0.05 mg/l to 0.83 mg/l. Zinc and strontium also increased, with the former reaching 0.208 mg/l by the 9th day.
The River Mapusa at Taricode saw manganese rise from 0.018 mg/l to 0.144 mg/l on day 9. Cadmium (0.08 mg/l) and mercury (0.001 mg/l), absent before immersion, were detected in post-immersion samples.
Carambolim Lake, a notified wetland, recorded a manganese increase from 0.014 mg/l to 0.079 mg/l by day 9. Strontium doubled to 0.072 mg/l, while zinc reached 0.037 mg/l on day 3 before tapering.
The Charkhamba section of the St Cruz river showed lead on days 3, 5, and 7, with levels reducing from 0.010 mg/l to 0.004 mg/l. Zinc concentrations rose to 0.121 mg/l and 0.130 mg/l on days 7 and 9
before declining.
In Sanguem, the Orcotto site showed manganese increasing from 0.055 mg/l to 0.197 mg/l on day 3, while strontium reached 0.098 mg/l on day 9. At Pimpolcotto, manganese was 0.293 mg/l with traces of mercury. At Curchorem Railway Bridge, manganese peaked at 0.669 mg/l on day 9, while zinc rose to 0.037 mg/l on day 15.
GSPCB attributed the contamination to synthetic paints containing lead, chromium, and cadmium, as well as Plaster of Paris idols releasing sulphates and metals.
