Groundwater Monitoring Event at a South-Western Sydney Galvanising Facility

Why licensed galvanising sites keep monitoring groundwater

Galvanising facilities can leave a long groundwater story: acidic conditions that keep zinc and lead mobile, ammonia hotspots, and licence conditions that require ongoing evidence that the remediation strategy still holds. A Remediation Action Plan (RAP) only works if someone keeps measuring against it.

At a galvanising facility in south-western Sydney, iEnvi completed the 2026 groundwater monitoring event (GME) to meet RAP requirements and the conditions of the site’s Environment Protection Licence (EPL). Licensed industrial sites typically run GMEs on a set cycle; this scheduled round was brought forward to capture seasonal variation outside the usual monitoring window, which adds useful context to the long-term dataset.

Sampling seven wells with HydraSleeve methods

An iEnvi environmental scientist gauged the monitoring network and sampled seven accessible wells using HydraSleeve methods, which recover a discrete sample with minimal disturbance to the water column. Primary samples went to a NATA-accredited laboratory for analysis of dissolved zinc, dissolved lead and ammonia as N, supported by field duplicate samples and laboratory quality control for the metals suite.

Results were interpreted against the remediation assessment criteria and historical trend charts, then reported under CEnvP Site Contamination Specialist review for submission to NSW EPA. That senior review step is standard practice across our contaminated land work, because a regulator reads trend interpretation as closely as the numbers themselves.

What the 2026 groundwater results showed

Long-term monitoring continues to show an overall reduction in contaminant concentrations across the site, particularly for zinc. The historic hotspot well remains the main on-site concentration area, and acidic pH there continues to favour metal mobility, so no one is pretending the hotspot has disappeared.

Concentrations remain elevated in parts of the on-site network, which is why monitoring continues. Results at the network boundary were consistent with the downward long-term trend and with receptors remaining protected under the current program.

Well maintenance and network housekeeping

A well-run GME also looks after the infrastructure that produces the data. This round flagged two practical actions:

• Repair of one well cover to keep debris out of the well and protect sample integrity.
• Decommissioning of several long-idle wells that have not been sampled since 2011, keeping the network lean and the dataset defensible.

Continuing the Groundwater Monitoring Plan and natural attenuation strategy

The 2026 GME supports continued implementation of the Groundwater Monitoring Plan and the natural attenuation strategy adopted for the site. Natural attenuation is a legitimate remediation approach, but only while the data keeps backing it: transparent trends, EPA-ready reporting and clear maintenance actions, round after round.

Because concentrations are still elevated in parts of the network, the program continues, but the long-term trajectory is downward. That is what a GME under a RAP and EPL is for: showing the regulator, and the site owner, where things actually stand.

Due for a GME under your RAP or Environment Protection Licence?

iEnvi runs groundwater monitoring events for licensed industrial sites across New South Wales, from gauging and HydraSleeve sampling through to CEnvP-reviewed reporting for NSW EPA. If your next monitoring round is approaching, or your network needs rationalising, talk to iEnvi about scoping it properly.