IPB University Professor: Green Shell Waste Piles Threaten Cilincing Coastal Ecosystem
The piles of green shell waste accumulating in the coastal area of Cilincing, North Jakarta, are considered by IPB University researcher Prof Etty Riani to be a threat to the existing ecosystem.
“The accumulation of organic waste not only disturbs the aesthetics of the environment, but also threatens coastal ecological stability and public health,” said Prof Etty, Professor at the Faculty of Fisheries and Marine Sciences (FPIK) at IPB University.
She explained that the organic material from green mussel shells undergoes decomposition by microorganisms. This process is accelerated by physical factors such as the heat of the sun and chemical reactions with seawater. Over time, the shells degrade, decay, and release various inorganic compounds into the environment.
“When these inorganic materials or nutrients are released in excessive amounts, several water quality parameters can fall below quality standards. This condition causes the quality of seawater to decline,” said Prof Etty.
On the other hand, high nutrient concentrations have the potential to trigger eutrophication (uncontrolled growth of phytoplankton). At night, phytoplankton require oxygen for respiration, in addition to the oxygen needed for the decomposition of organic matter.
“At night, the level of dissolved oxygen in the water can drop dramatically. If this continues, it can cause the death of various aquatic biota, and even trigger mass mortality,” she said.
Heavy Metal Contamination
The results of Prof Etty and her team’s research on green mussels in Jakarta Bay, including the Cilincing area, show that both the shells and flesh of the mussels contain a number of harmful heavy metals such as Hg, Pb, Cd, Cu, Cr, and Zn.
With shell accumulation reaching 1–4 tons per day, Prof Etty assessed that the risk of heavy metal contamination in soil, water, and coastal sediments has increased sharply.
“Heavy metal contamination does not stop at soil or sediment. These hazardous materials can be absorbed by the roots, stems, and leaves of mangroves, and also transferred to other aquatic biota through the process of eating or biomagnification, ultimately endangering the health of humans who consume various marine biota,” she explained.
If left unchecked for a long time, these heavy metals have the potential to cause physiological disorders, organ damage, reproductive failure, and even birth defects in aquatic organisms. In addition, compacted shell deposits can damage soil and sediment structures, permanently reducing ecological quality.
Apart from ecological impacts, shell accumulation can also trigger the emergence of disease vectors. “I have not found any studies that mention shellfish or fish around the accumulation site being contaminated with pathogenic bacteria. However, in general, waste piles like this usually become a breeding ground for flies, parasites, and other pathogens that can interfere with public health,” said Prof Etty.
She emphasized that green mussel shells should not be dumped indiscriminately in coastal areas. She advocated for the establishment of special locations to store such waste so that it does not pollute the environment or become a source of disease.
Prof Etty also reminded that shells should not be used for human consumption, animal feed, or fertilizer as long as they still contain heavy metals, unless the shells are treated with special technology to remove these harmful and toxic substances.
As a circular economy-based solution, she recommended using shells for non-consumption products.
“Cleaned shells have attractive colors and have the potential to become economically valuable craft materials. Shells can also be used as a substitute for CaO or CaCO₃ in concrete mixes, bricks, paving blocks, and other applications,” she concluded. (AS)(IAAS/RWA)
