Plastic pollution of the sea is increasingly alarming. Apart from poisoning marine organisms, plastic pollution also threatens mankind. Two recent studies have found microplastics in Indonesian maritime products.
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JAKARTA, KOMPAS — Plastic pollution of the sea is increasingly alarming. Apart from poisoning marine organisms, plastic pollution also threatens mankind. Two recent studies have found microplastics in Indonesian maritime products.
The separate studies, one from Hasanuddin University in Makassar, South Sulawesi, and the other from the Indonesian Institute of Sciences’ (LIPI) oceanographic research center, have found microplastics in salt and fish from Indonesia. “We found 10-20 microplastic particles in 1 kilogram of salt. The type of plastic is similar to that in the water, sedimentation and [marine] biota,” LIPI ecotoxicologist and marine chemist Reza Cordova said in Jakarta on Thursday (29/11/2018).
Reza said his research on microplastic content in salt was conducted in fish ponds at Java’s northern coast, namely in Pati, Kudus, Demak and Rembang. “We believe the microplastics in the salt come from polluted water. There is also the possibility of microplastics getting into the salt after harvesting, where plastic is widely used,” he said.
Microplastics are plastic particles measuring less than 5 millimeters (as large as a sesame seed) down to 330 microns (0.33 mm) in diameter.
Meanwhile, Hasanuddin University maritime and fishery sciences professor Akbar Tahir said the university’s research was conducted at salt ponds in Jeneponto, South Sulawesi. “We took samples of water, sediments and salt from ponds with water sourced from the sea. Sampling was done twice at eight sites, producing a total of 16 water samples,” he said.
Akbar said all seven studied salt samples contained microplastics, with a total contamination level of 58.3 percent. Meanwhile, of the 16 studied water samples, 11 were found to contain a total of 31 plastic particles with a total contamination level of 68.75 percent.
In the 16 studied sediment samples, 41 microplastic particles were found at a total contamination level of 50 percent. “The total contamination is the ratio of positive samples among the total of samples studied,” Akbar said.
Single-use plastics
Reza said the pollutant in salt could be traced back to microplastic pollution in seawater. “The plastic mostly comes from single-use plastics, such as plastic bags. We also found plastic from fishing nets and clothes,” he said.
Reza continued that his research on microplastic content in seawater was conducted at 13 sites, all of which were polluted at levels ranging from 0.25 particles per cubic meter to almost 10 particles per cubic meter. “The worst microplastic pollution was on the coasts of Jakarta and South Sulawesi, namely at 7.5-10 particles per cubic meter,” he said.
He went on to say that he also found microplastic pollution in his research on anchovy and other fishes at 10 sites in Indonesia. “Between 58 percent and 89 percent of anchovy is polluted with microplastics. The highest concentration was found in Makassar and Bitung,” he said.
Previous research from Hasanuddin University and the University of California, Davis, found microplastic pollution in the digestive tracts of fishes and shells sold at Makassar’s largest fish market. The research results were published in the international science journal Nature in September 2015.
That study analyzed 11 species of fish and found that 28 percent of the samples contained microplastics. The result was that many fishes, from anchovy to mackerel tuna, were contaminated. Of the 10 anchovies studied, four were contaminated with plastic.
Akbar said these findings served as a warning about the seriousness of plastic waste pollution of the seas. “Serious steps must be taken to resolve this plastic waste problem. For salt, this can be achieved technically by filtering the seawater used in the production, even if this will result in a salt price hike. However, what about fish?” he said.
Agung Dhamar Syakti, the dean of the maritime and fishery sciences school at Raja Ali Haji Maritime University in Riau, said plastic waste of the seas could release poisonous chemical compounds, such as nonylphenols. Microplastics may also bond with poisonous pollutants, such as pesticides and heavy metals, which may cause cancer, genetic mutation or embryo damage.