Plastic bags carry bugs dangerous to humans after just 6 weeks in sea
BACTERIA that are harmful to humans can stick to plastic bags in the ocean in less than six weeks.
Scientists who cut up singleuse carrier bags and submerged them in the sea found thick layers of bacteria were able to cling to the plastic within 40 days.
There are growing fears the plastic choking our oceans could cause illness in humans, as the material acts as a magnet for toxins in the water – and waste swallowed by fish makes its way up the food chain.
Researchers at National University in California were particularly interpolyethylene ested in floating fragments of plastic bags, which the Daily Mail has campaigned to banish.
The scientists cut plastic bags into squares and put them in stainless steel cages 20in under the surface of the sea.
Analysing the microbes on the plastic, they found bacteria that cause serious fevers, including one similar to strains used in biological terrorism.
Study leader Dr Ana Maria Barral said: ‘We were very surprised to see plastics in the water were colonised so quickly.
‘There was potentially diseasecausing bacteria … It is scary because we think about plastic being harmful to fish and sea life but we don’t always think about the microbes it attracts and the problems this could cause. We looked at the effect of plastic pollution in coastal waters, where there is a risk of people coming into contact with the bacteria.’
It is a decade since the Mail launched its Banish the Bags campaign calling for a 5p charge on carrier bags. Since the policy was adopted, the number of plastic bags given out at tills has fallen by 7billion a year.
The study used high-density ( HDPE) bags, which are thin and often used only once before being discarded, and those made from low- density polyethylene (LDPE), used in bags for life and more durable bin bags.
‘They also submerged a type of plastic resin called polypropylene, used in yoghurt pots and margarine tubs.
The plastics were retrieved at four different times, between three and 40 days in to the experiment, with nearby water samples also taken.
Dr Barral said: ‘Bacteria are attracted to thicker plastic because it has so many little crevices and nooks which it can fill and grow in. The plastic bags have a smooth surface which they attach to.
‘We saw quite a thick build-up of bacteria, 40 per cent of which came from unclassified organisms … more research is needed to know what is forming on ocean plastic.’
The microbes retrieved include bacteria from the group Francisella, which causes ‘rabbit fever’ and which humans can be exposed to through contaminated water, infected animals and tick bites. It starts with a high fever and can be life-threatening, although most cases can be treated with antibiotics.
Officials have warned that strains of Francisella could be used as a weapon by terrorists engaging in biological warfare.
The scientists also found bacteria from the group Rickettsia, which causes ‘spotted fever’. The majority of cases are in the US, but it has also been found to be carried by birds in the UK.
The study, also involving the Scripps Institute of Oceanography in California, was presented during the Experimental Biology annual conference in San Diego.
‘Thick build-up of bacteria’