Bio-enzymes not to be used for cleaning natural water bodies: CPCB

CPCB advises against using bio-enzymes for cleaning natural water bodies due to ecological risks and lack of scientific validation for long-term effects.

The Central Pollution Control Board (CPCB) on April 2 submitted to the National Green Tribunal (NGT) its findings that bio-enzymes and similar chemical substances should not be used for cleaning or treating natural water bodies such as rivers, streams and lakes due to ecological concerns.

In its report, the CPCB stated that the use of bio-enzymes, including products like Draynzyme, is not suitable for ecological restoration. (HT)

In its report, the CPCB stated that the use of bio-enzymes, including products like Draynzyme, is not suitable for ecological restoration or purification of natural water sources due to lack of adequate scientific evidence about their long-term environmental impact.

The matter originates from a suo moto case initiated by the NGT based on a Hindustan Times report dated February 23, 2024, titled, “No permission provided for use of chemicals in cleaning water bodies: MPCB.” The report had highlighted the Pune Municipal Corporation (PMC)’s use of bio-enzymes and insecticides in rivers without necessary approvals. In its submissions, the PMC stated that Draynzyme was used on a trial basis to tackle water hyacinth and pollution. The civic body had sprayed the product over a small, 40 square feet patch of stagnant water along the Ramnadi in Bavdhan. The PMC had also relied on a case study provided by the manufacturer, which described Draynzyme as an enzyme-based formulation containing multiple enzymes such as urease, lipases, proteases and oxidoreductases. According to the case study, the product has primarily been used for sewerage cleaning and sludge reduction rather than for direct application in natural flowing water bodies.

The CPCB noted that while such formulations may help in breaking down organic waste in drains, the case study submitted by the PMC does not provide sufficient scientific validation for the use of the said enzyme in rivers or lakes. It also lacks clarity on dosage, long-term ecological impact and the behaviour of the enzymes in complex aquatic ecosystems.

Toxicity studies conducted by the CSIR-Indian Institute of Toxicology Research (IITR) did not indicate any immediate harmful effects on aquatic life. However, the assessment was based on short-term exposure, and experts observed that it did not address long-term ecological risks such as bioaccumulation or disruption of microbial balance.

A committee constituted by the CPCB, with inputs from institutions including CSIR-National Environmental Engineering Research Institute (NEERI), as well as independent experts, reviewed the findings and raised concerns over the absence of comprehensive chemical characterisation, peer-reviewed validation and ecological risk assessment. Experts also cautioned against large-scale application of such products in natural ecosystems without detailed scientific studies.

Based on these findings, the CPCB concluded that Draynzyme cannot be recommended for river cleaning, lake restoration or water hyacinth removal. However, it stated that the product may be considered for limited use in sewage drains or stagnant wastewater channels under controlled conditions, with strict monitoring, periodic sludge removal and water quality testing to ensure that no additional pollution load reaches natural water bodies.