Tiger snakes tell more about local wetlands' pollution levels

June 02, 2020

Tiger snakes living in Perth's urban wetlands are accumulating toxic heavy metals in their livers, suggesting that their habitats - critical, local ecosystems - are contaminated and the species may be suffering as a result.

Lead researcher PhD Candidate Mr Damian Lettoof, from the Behavioural Ecology Lab in the School of Molecular and Life Sciences at Curtin University, said that not only were the snakes' livers shown to contain moderately high levels of heavy metals, but sediment samples taken from some of the wetlands sites were found to have amounts of arsenic, lead, mercury and selenium that exceed current government guidelines.

"Urban wetlands are almost always polluted, commonly from contaminated storm water, past or present dumping of waste, and spill events," Mr Lettoof said.

"Wetlands areas are usually situated at low points in the landscape, so unfortunately, a lot of urban run-off ends up in them. Generally speaking, the longer the wetland has been urbanised, the higher the levels of pollution.

"It's important to note that many heavy metals exist naturally in the wetlands sediment and surrounding rocks, in low concentrations, which may cause some heavy metals to leach in to the wetlands environment.

"However, the high concentrations of heavy metals we found in the snakes' livers and sediment samples suggest urbanisation and human-induced pollution are the cause, and consequently could be affecting local snake populations," Mr Lettoof said.

The study found the metal concentrations in the snake livers were collectively highest in Perth's most urbanised wetland: Herdsman Lake in the north western suburbs.

"Snakes tested from Herdsman Lake also had the highest concentration of the metal molybdenum ever reported in a terrestrial reptile, in the world," Mr Lettoof said.

"Continuous, chronic exposure to contaminants can have a range of impacts on the health and behaviour of animals. The contaminated populations could be suffering poorer health conditions, leading to shorter lifespans, higher predation, and ultimately, local extinction with cascading consequences such as reduced local biodiversity."

Collectively, Lake Joondalup had the lowest levels of metals. The researchers also analysed samples from Bibra Lake and Loch McNess in Yanchep National Park.

Tiger snakes are a top predator in the wetlands environment, and most likely have bioaccumulated the heavy metals through eating frogs, which are very sensitive to accumulating contaminants.

The Curtin University study was the first of its kind in Australia to show that snakes are a good bio-indicator of wetland contamination, and highlights the use of monitoring snake populations as an important indicator species of environmental health.
The full research paper, The Broad-Scale Analysis of Metals, Trace Elements, Organochlorine Pesticides and Polycyclic Aromatic Hydrocarbons in Wetlands Along an Urban Gradient, and the Use of a High Trophic Snake as a Bioindicator, was published in the Archives of Environmental Contamination and Toxicology.

Curtin University

Related Heavy Metals Articles from Brightsurf:

Dairy cows exposed to heavy metals worsen antibiotic-resistant pathogen crisis
Dairy cows, exposed for a few years to drinking water contaminated with heavy metals, carry more pathogens loaded with antimicrobial-resistance genes able to tolerate and survive various antibiotics.

Liquid metals come to the rescue of semiconductors
Two-dimensional semiconductors offer a possible solution to the limited potential for further shrinking of traditional silicon-based electronics: the long-predicted end of 'Moore's Law'.

Heavy metals make soil enzymes 3 times weaker, says a soil scientist from RUDN University
Heavy metals suppress enzyme activity in the soil by 3-3.5 times and have especially prominent effect on the enzymes that support carbon and sulfur circulation.

Semiconductors can behave like metals and even like superconductors
The crystal structure at the surface of semiconductor materials can make them behave like metals and even like superconductors, a joint Swansea/Rostock research team has shown.

Metals could be the link to new antibiotics
Compounds containing metals could hold the key to the next generation of antibiotics to combat the growing threat of global antibiotic resistance.

Instrument may enable mail-in testing to detect heavy metals in water
MIT researchers have developed an approach called SEPSTAT, for solid-phase extraction, preservation, storage, transportation, and analysis of trace contaminants.

A new look at 'strange metals'
'Strange metals' could be the key to finally understanding high-temperature superconductors.

Flame retardants and pesticides overtake heavy metals as biggest contributors to IQ loss
Adverse outcomes from childhood exposures to lead and mercury are on the decline in the United States, likely due to decades of restrictions on the use of heavy metals, a new study finds.

Stellar heavy metals can trace history of galaxies
Astronomers have cataloged signs of nine heavy metals in the infrared light from supergiant and giant stars.

Microwave treatment is an inexpensive way to clean heavy metals from treated sewage
A team of Florida State University researchers studying new methods to remove toxic heavy metals from biosolids -- the solid waste left over after sewage treatment -- found the key is a brief spin through a microwave.

Read More: Heavy Metals News and Heavy Metals Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.