A deeper dive into Acid Sulfate Soils. In a slightly QLD centric episode, Gunnar and James are joined by all three main authors of the QLD ASS Management Guidelines, widely regarded as the best ASS guidelines in the world.

Sue-Ellen Dear is a Senior Land Resource Officer with the QLD Department of Natural Resources and Mines and has contributed to acid sulfate soil policy and guidance since 1996. She is lead author of the QLD ASS Management Guidelines.

Kristie Williams has spent nearly 25 years in the QLD government soils team, working across ASS, salinity, erosion and land resource assessment. She has authored technical reports, contributed to regulations and assessed developments from small works to major canal estates.

Dr Angus McElnea developed the SPOCAS method, co-authored Australian and international standards and is a NATA technical assessor.

They unpack how acid sulfate soils form and what really happens when these soils are disturbed. They cover pyrite formation, potential vs actual acid sulfate soils and the “trinity of acidities” and then discuss real-world management challenges.

They put forward avoidance of disturbing ASS as the first priority, the realities of liming and mixing on treatment pads, the controversy around acid neutralising capacity, and why incubation testing matters. They talk about strategic reburial, the pros and cons of centralised treatment facilities, the carbon cost of treating ASS, and the industry’s tendency toward conservative safety factors (with a small Gu-rant - they are always audience favourites so we hear)

The episode finishes with validation testing, safe reuse of treated soils and the future of professional certification through the Registered Soil Practitioner scheme.

If you work in contaminated land, coastal development, infrastructure or groundwater, this episode is essential listening.

Links:

BTS #23: The Basics: Acid Sulfate Soil

Legislation and policies for ASS management in Qld

ASS guidance material

Retained Acidity Technical Note

SNAS correction by NATA

Gunnar loves ASS

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The necessary disclaimer: The views, thoughts, and opinions expressed in this Podcast are the speakers’ own. They do not necessarily represent the views, thoughts, and opinions of 4Pillars Environmental Consulting Pty Ltd or any Client, Supplier or other party related to 4Pillars or the speakers.

(c) Gunnar Haid and James Hammond

How much of any given contaminant is actually taken up into human bodies?

If we think about it, that is one of the single most important things to consider as an environmental consultant when reporting on a site's contamination status, yet it is not something that is very often done. Gunnar and James are yet again soaring with an industry eagle as they set out to get better at that very aspect of consulting.

They chat with Dr Albert Juhasz, a Research Professor at the Future Industries Institute, internationally recognised for cross-disciplinary research on contaminant bioavailability and human health exposure. He has led development of one of the world’s largest contaminant bioavailability databases and advanced in vitro methods now applied at more than 100 contaminated sites across Australia.

His work has informed national and international exposure assessment policy, including the ASC NEPM and EnHealth Guidelines, and influenced regulatory guidance in the US, Canada and New Zealand. Albert is a senior journal editor, WHO consultant, contaminated-site auditor adviser, and a highly cited researcher (H-index 37).

The episode was recorded on 7 November 2025

Listen to Below the Surface and collect CPD points. We have confirmation that you can claim 0.5 points for every hour you spend with us under the Self Education Category

Contact: bts@4pillars.com.au

https://www.linkedin.com/company/below-the-surface-podcast

The necessary disclaimer: The views, thoughts, and opinions expressed in this Podcast are the speakers’ own. They do not necessarily represent the views, thoughts, and opinions of 4Pillars Environmental Consulting Pty Ltd or any Client, Supplier or other party related to 4Pillars or the speakers.

(c) Gunnar Haid and James Hammond

The 2025 Year in Review (That Wasn’t Supposed to Happen)

What started as a neat 15-minute intro quietly turned into a full end-of-year wrap-up. Classic Below the Surface. Gunnar and James get side-tracked almost immediately and eventually realise they have recorded the accidental 2025 BTS year in review. They cover listener feedback, behind-the-scenes stats, favourite episodes and a special mention for Sandgate.

Personal obsessions make an appearance, with both sharing their top five podcasts of the year. Strong opinions, minimal overlap, and proof that podcast hosts mostly listen to other podcasts.

On the technical front, Gunnar explains why the new AS 5370 feels like a step backwards, followed by a familiar rant on mandatory low-speed EV noise in Australia. EVs also feature heavily, including the claim that at least 11 new electric vehicles have hit Sydney roads thanks to a BTS episode.

The EPA gets its own moment, with discussion of recent turmoil, announcements that feel straight out of Utopia, and Gunnar’s practical solution to the EPA’s budget problems. They finish with updates on Resource Recovery Orders, the new ASS RRO, and thoughts on a possible National EPA.

Unplanned, slightly chaotic, and very on brand. A fitting way to wrap up 2025.

Links:

Gunnar's Top 5 Podcasts

The Tennis Podcast

Uncomfortable Conversations with Josh Szeps

Andy Roddick's Served Podcast

The Michael Shermer Show

Joe Rogan (his interview with Lance Armstrong: https://www.youtube.com/watch?v=rEfSdPz1WtA)

All the other podcasts Gunnar subscribes to in one handy link

James' favourites

The Imperfects Podcast

Two Broke Watch Snobs

Democracy Sausage with Mark Kenny | Australian Studies Institute

The Rights to Ricky Sanchez - A podcast about the Philadelphia 76ers

The Art of Manliness

This BTS Episode was recorded on 12 December 2025

Listen to Below the Surface and collect CPD points. We have confirmation that you can claim 0.5 points for every hour you spend with us under the Self Education Category

Contact: bts@4pillars.com.au

https://www.linkedin.com/company/below-the-surface-podcast

The necessary disclaimer: The views, thoughts, and opinions expressed in this Podcast are the speakers’ own. They do not necessarily represent the views, thoughts, and opinions of 4Pillars Environmental Consulting Pty Ltd or any Client, Supplier or other party related to 4Pillars or the speakers.

(c) Gunnar Haid and James Hammond