A landmark study into the concentration of elements, bacteria and microplastics in Upolu waters is a solid foundation for more research, a leading scholar on water has said.

Professor Stuart Khan said while the research is not enough for its own conclusions it provides a base for significant further study.

“It’s a good study and worth going back in a year, five or ten years’ time and seeing whether or not there are trends of things changing and that will tell you something interesting,” the Civil and Environmental Engineering professor said. 

“They have pointed to a number of things that are worth following up, particularly whether some chemicals have been accumulated by corals or whether corals are deficient in some chemicals. 

“I think there is potentially some good science to do around that.”

The report, Biosecurity of Upolu Fresh and Salt Environmental Water Resources, was published jointly by New York University in New York and Abu Dhabi, the Ministry of Natural Resources and Environment (M.N.R.E.) and the National University of Samoa (N.U.S.), under a partnership facilitated by the United Nations Development Programme in Samoa.

The research team gathered 219 water samples from 35 rivers, three lakes, and seawater samples from 39 inner reef, reef and outer reef locations around Upolu over two weeks in December 2019.

They also took water samples of rainwater and bottled water. Using highly advanced mass spectrometry technology, they tested those samples at the Abu Dhabi and New York N.Y.U. campuses and at N.U.S.

The water was tested using a Colilert 18 (I.D.E.X.X., U.S.) testing kit, which is U.S. E.P.A. approved. It can detect a single pathogenic bacterial cell 100 millilitres of water.

Based on the research, a second paper has been published in the scientific journal Molecules with the analysis of the elemental composition of the water samples. The paper was published at the end of October.

N.Y.U. Professor Emeritus Dr. Gary Goldstein, co-author and project lead, said among the purposes of the research was to provide a base of data to compare to when mitigation efforts are deployed, especially for organisations like the United Nations (U.N.). 

“Say for example Samoa decides they want to do A, B, C, and D, […], they come up with a plan and now X number of years later somebody says let's go test and see if it works.

“The U.N. would want to go back in and re-test to make sure that the things were done really worked. If they are spending so much money to do mitigation, then how will they know if the money is well spent or not? 

“It’s not a Samoa issue, it’s a U.N. Headquarters discussion about how we can use this technology to protect coral reefs in other places around the world.”

Professor Khan, who is from the University of New South Wales in Sydney, said the papers point to areas that could do with further study. 

In particular the impacts of certain elements or bacteria that are either in abundance or appear deficient on coral reef health should be addressed.

“They talk about work that could be done in understanding whether or not coral have adapted to these low concentrations of some chemicals, understanding the sources of magnesium, calcium and bromine that they suggested were elevated and maybe because of pesticides,” Professor Khan said.

“I think those sorts of follow ups are sensible and useful but I definitely wouldn’t jump to the conclusion that they are the sources without having the follow up investigation.

“Is it just simply that this particular reef is a different eco system that has evolved differently to others or is there a problem? 

“Part of the way to answer that question is to ask if there is something changing over time. There are a few ways to answer that and one is with long-term monitoring. 

“But in lieu of waiting there might be biological records of the concentrations of various chemical substances so you need a good biologist to tell you where to look.”

The report suggests that high concentrations of the elements found in pesticides, metals from the fisheries industry and bacteria were found the water samples and the authors are concerned this could affect coral.

The researchers worry some of these chemicals have negative impacts on both coral and human health.

“These chemicals have endocrine effects that may contribute to endemic obesity and they are also highly toxic to aquatic life,” they write.

There are also some elements that coral reefs need for growth that were found in lower than expected concentration levels.

“Barium and strontium are essential for the growth and construction of stony corals, yet concentrations of these elements are very low around Upolu Island,” they write.

“These insufficiencies require investigation. Historically this may be investigated by sampling coral skeletons retrieved at known dates in the past […]  There is no explanation for how these elements can be sequestered to such levels.

“Silicon is also essential for the construction of stony corals and for growth of important algal lineages such as diatoms; […] the contrast between high freshwater sources and low seawater concentrations suggests that excess inputs due to farming activities and/or climate effects may be dumping silica from the rivers into the sea, which falls from surface waters to the sea floor and potentially obscuring the coral reef surface, thus decreasing the coral reefs' ability to thrive.”

But Professor Khan is concerned there is not enough data to be making such detailed conclusions yet.

“I think some of the public health comments they have made are unjustified in that they have identified high concentrations of things like calcium and magnesium which are ubiquitous chemicals in the environment,” he said.

“I don’t think they have anywhere near enough data to make that link and I think it’s a bit of a dangerous link to make without evidence because if obesity is a real public health problem we should be really making sure we know what the causative factors are before pointing the finger to some that may actually not be the key causative factors.

“There is a danger in suggesting it comes from some environmental source when really there are other risk factors that should have more attention paid.”

He said the specific methods the research deployed also makes the study a little difficult to use.

Though detailed, the methods used to look at a large number of chemicals at the same time makes the study had to compare to other studies and learn more about what is happening in the water.

“It’s a technical point but I think the novelty of the instrumentation they have used means there is a little bit more uncertainty than normal about the actual concentrations. 

If there had been more conventionally used techniques, then I might have a little bit more confidence in the concentrations reported. I am not saying there is anything wrong with it, it just makes it a little bit uncertain.”

The data is also not compared to any historical data in order to glean trends over time he added.

Each sample of water can be broadly looked at for the concentration data of each element tested, except for five which lacked sufficient data.

Professor Khan said he would have liked to see the overall results more easily compared across locations.

“I find it pretty difficult to say that anything they are measuring is really a red flag of something exceptional.”