A team of scientists have revealed that the cigarettes butts thrown away on beaches lead to an increase in toxic heavy metals in oysters.
The research carried out by scientists at the Spanish Institute of Oceanography of Vigo, in the northwestern Spanish region of Galicia, alongside French water pollution monitoring organisation CEDRE.
The results were published in the Journal of Hazardous Materials and showed how heavy metals from cigarette butts thrown away on beaches dissolve into the sea and are then absorbed by the gills and digestive glandule of oysters.
Juan Santos-Echeandia, 40, researcher at the Spanish Institute said in an interview with Real Press that: “Cigarette butts are one of the ten most common types of waste found on beaches.”
He also explained that butts are in six percent of the monitored garbage in the Atlantic coast and in some areas concentrations of 1,000 butts are found for every 100 metres (feet) of beach.
The butts have severe effects on the environment, not only because of the visual pollution but also because of the physical effects they have on marine life.
Often animals will digest the butts resulting in suffocation and in some cases, they have toxicological effects.
The new research has quantified the transfer of heavy metals from the filters of the cigarettes to the sea and how once they are in the sea, they are absorbed by oysters.
The doctor explained that during the lab experiments four different types of butt were tested: a virgin one, meaning not smoked, a smoked one, a smoked one that had degraded on a beach and a smoked one that had degraded in a port.
He said that: “We firstly used a device in the lab to smoke the cigarette and we used different brands of cigarettes in order to find out if the gathering of metals was different in the virgin and the smoked butts.”
He added that: “we confirmed that the butts after smoking had high levels of heavy metal presence, especially copper, cadmium, zinc”.
He explained that: “The metals and amount of metals contained in tobacco plants is decided by the type of soil in which they are grown.”
The research showed that the smoked butts contained a 90 times higher concentration of metals than the unsmoked ones.
The smoked butts were left on beaches and in ports on the Atlantic coast of France where they were monitored carefully to see how levels of metal in the butts changed over time.
The doctor said that: “the research confirmed that in both places the levels of metal in the butts increased over time”
He went on: “However, a larger increase was seen in those left in the port because the area is more contaminated with metal than the beach.”
Once the butts are washed into the sea they release their metals.
The research concluded that copper was the element that dissolved into the water fastest with 90 percent of all copper absorbed by the butts being deposited into the sea.
While Strontium was the lowest with the butts only depositing an estimated 40 percent of Strontium they absorbed.
The following phase of the research was aimed at establishing if the metals released into the ocean by the butts pose a toxicological risk to marine organisms.
The researchers used oysters for the experiment and found that: “the levels of metals in the oyster tissues increased around 5 per cent, so not a lot,”
They added with these results: “we cannot know if this is having a toxic effect on the oysters so more research will need to be done in the future.”
The research did show that the tissue samples presented an increase in concentrations of strontium, manganese, uranium, chromium, iron, molybdenum, lead and zinc, not only in the gills but also in the digestive glands.
However, research was carried out under controlled conditions in a lab, and as a result, extrapolate the findings to oysters living in the sea cannot be done.
The doctor explained that the metals released into the sea are potentially more diluted than those in the lab and as a result concentration would likely be different.
According to Santos-Echeandia: “the metals gathered in the oysters could cause effects such as the decrease of their growth, problems in the breeding and with other metabolic processes”
He added: “that this could lead to them dying” but he also added that: “the levels found in the research are not high enough to lead to these side-effects.”
Santos-Echeandia mentioned the potentially damaging effects of consuming oysters with high levels of toxic metals could have on humans but he said that due to strict protocols surrounding the sale of oysters which required them to be tested for metals before sales make it unlikely that humans would consume oysters high in metals directly.
However, indirectly the metals could make their way to humans as according to the doctor the oysters are in the middle of the food chain.
He explained that the oysters: “could be eaten by an octopus or other marine animals allowing the metals to move up the food chain and potentially be consumed by humans.”
Due to this research, the scientist warned about the need to prevent, reduce and mitigate the environmental impact of the butts as an estimated 5 billion of them wash into the sea globally every year.
He concluded that additional funding could be allocated to programmes that make people aware of the dangers of throwing cigarette buts away on beaches, labelling the cigarette packages as dangerous waste material or by handing out fines to people caught throwing away the butts on beaches.”