Contaminated post-industrial sites proliferate across Australia. Brownfield sites sit vacant, often still housing the infrastructure that contaminated the soil in the first place. The Delprat Cottage site, located on the former BHP steelworks in Newcastle, now accommodates experimental gardens using low cost, natural, phytoremediation techniques to restore toxic land.
NSW’s Hunter Valley is home to over 1000 toxic sites, with fifty of those located within Newcastle’s LGA. One of these, the heritage listed 1914 Delprat Cottage and its surrounds, is the former home of BHP‘s General Manager. The steelworks closed in 1999, and while many of the site’s buildings were raised, the soils still contain a cocktail of deadly contaminates. Addressing long term issues of environmental pollution, the gardens actively remove the toxins present on the site, while educating the public about this form of remediation, and preparing the land for future uses.
Delprat Gardens are an experimental, bio-technical design research project. The gardens reinstitute regimes of care by utilizing phytoremediation processes, whereby plants absorb toxins from the soil, revealing new discoveries about their natural restoration capabilities. The project involves growing and testing native and introduced plant species for specific toxin absorption and metabolism via four garden designs – a kitchen garden with edible species, a cottage garden, orchards with under-plantings, and flowering meadows, in a community activated, aesthetically appealing space. Creating a spark of beauty and hope amidst toxic wastelands, which serve as a testament to nature's resilience and cyclicality.
Delprat Gardens provides important research and education for students, academics, practitioners, government partners, and the wider community. Since the initial 2019 meadow plantings, the site’s most toxic area now meets Australian environmental standards for acceptable soil toxicity levels. The community is welcomed to the site through open days, hosting visits from Garden Clubs, TAFE, and local schools, and was showcased recently on Gardening Australia. The film HUMUS exhibited in the 2021 Venice Biennale featured the gardens to an international audience. The gardens celebrate phytoremediation techniques as productive ecologies, restoring degraded land in a beautiful, emergent, expressive, and educative manner.
The kitchen garden includes annual and perennials herbs, vegetables, fruits, and flowers. The implications of edible plants and pollinators absorbing toxins ensures popular attention to this garden. The cottage garden will be tested for toxin absorption over a seven to ten year period, with testing taking place once the plants are established. The orchards are longer-term plants to determine the cleansing ability and potential transmitting properties of tree species. They will also provide insight into the potential of street trees to thrive in toxic soils under high temperatures and less water due to climate change. The meadows are an example of broad-acre style planting, involving a low-cost planting method of annual and perennial grasses and flowering meadow species. This portion of the site is an example of how land developers can remediate larger acreage brownfield sites.
The data collected records not only the toxin/s absorbed, where the toxin might be stored in the plant, but also which plants might be safer to ingest for both humans and animals. The findings and results are published publicly, open access, on the Delprat Garden website, as well as a DIY Phytoremediation Garden guide to promote and educate others about phytoremediation.