Wildlife exposed to heavy metals in Kinabatangan

KINABATANGAN (Dec 5): In a new scientific study, conservationists have shed first light on cryptic pollution threats facing wildlife in Sabah.

Borne from a long-term collaboration between teams at Danau Girang Field Centre (DGFC), Sabah Wildlife Department and Cardiff University, these results come from the integration of cutting-edge research conducted in the heavily fragmented Lower Kinabatangan floodplain.

Since 2013, the Kinabatangan Small Carnivore Program (KSCP) has evaluated the health of small carnivores in the region, and this newest publication in Environmental Research dives deeper into characterising the trials and tribulations faced by adaptable native species.

Over the years, the team carefully captured and collected samples from wild Malay and common palm civets.

“For this particular project, we shaved a small section of hair from each civet,” said Dr Meaghan Evans, the project leader and first author of the paper.

“We went to our lab and quantified the levels of 13 different metals contained in each hair sample, which included contaminants of notable biological concern such as lead, mercury, chromium and cadmium.”

Metals, and particularly those commonly referred to as ‘heavy metals’, can be dangerous to not just animal, but also human health; biological effects following exposure to different metals range from relatively small issues such as skin irritation to markedly more serious repercussions such as infertility and even death.

“We know small carnivores are behaviourally adaptable: Malay civets can be found in forests, oil palm plantations, and even urban neighbourhoods. With this project, we harnessed this flexibility to establish these animals as indicator species, meaning we could identify the biological extent of metal contamination within the Kinabatangan Floodplain,” said Dr Meaghan.

“This region has been largely converted to oil palm plantations, and there have been no formal evaluations determining the ecotoxicological repercussions of such large-scale anthropogenic disturbance.

“We found certain metal levels in civet hair were associated with civet age, weight, proximity to tributaries, and access to oxbow lakes,” stated Dr Meaghan.

“During sampling events, we also fitted GPS-collars on male civets to document each animal’s use of forests and/or plantations. This allowed us to directly test the potential influence of agriculture on the metal levels we observed: indeed, civets that spent time in oil palm plantations had significantly elevated concentrations of aluminium, lead, and cadmium in their hair samples compared to animals that stayed in protected forests,” added Dr Meaghan.

“Although these data do not definitely identify the plantations as explicit sources (incidental or deliberate) of metals, our research certainly supports future evaluations of agricultural practices with sector partners. Identifying the sources and ecotoxicological pathways of these metals is the next crucial step to protecting wildlife and human welfare alongside economic development,” she said.

Finally, by pairing hair and blood samples collected from Malay civets, the KSCP team identified several associations between elevated metal levels and health metrics, including red blood cell morphometrics and liver enzyme functionality. “By synthesising these three uniquely different datasets – metal levels from hair samples, space use patterns from GPS-collars, and health status from blood samples – we were able to establish rigorous evidence of biologically-worrisome contamination within the ecosystem, which urgently warrants further evaluation,” said Mohd Soffian Bin Abu Bakar, Assistant Director and Head of Enforcement at Sabah Wildlife Department, and one of the co-authors of the study.

“Indeed, the publication of this groundbreaking research coincides with a press release last month issued by our department. In that report, elevated concentrations of cadmium were detected in samples from three dead Bornean elephants (Elephas maximus borneensis). Although neither of these studies directly identified the original sources of these metals, both provide irrefutable evidence of animal exposure to inorganic pollutants,” added Soffian.

Professor Benoit Goossens, director of Danau Girang Field Centre and one of the authors of the study, concluded that “Given our non-invasive methodology using hair clippings, our study does implicitly underestimate the lethal severity of metals in the Kinabatangan by the simple logic that poisoned civets would not live long enough to be captured and sampled by our traps. The implications of this research scales beyond wildlife: if excessive metals are circulating within an ecosystem, they will threaten human health. We will carry out further studies to identify the original sources of these metals and how animals are exposed to them.”

The work of the KSCP was funded with research grants from Houston Zoo, Phoenix Zoo, Ocean Park Conservation Foundation Hong Kong, and Yayasan Sime Darby.