Saturday, May 25, 2024


(Excerpts from the 2015 report of the UN Ad Hoc Working Group on the Regular Process for Global Reporting and Assessment of the State of the Marine Environment Including Socioeconomic Aspects. Silliman University’s Dr. Hilconida P. Calumpong is one of the Report authors.)

Increasing particles of harmful material
Nanoparticles are a form of marine debris, the significance of which is emerging only now. They are miniscule particles with dimensions of 1 to 100 nanometres (a nanometer is one millionth of a millimeter). A large proportion of the nanoparticles found in the ocean are of natural origin. It is the anthropogenic nanoparticles that are of  concern. Those come from two sources: on the one hand, from the use of nanoparticles created for use in various industrial processes and cosmetics and, on the other hand, from the breakdown of plastics in marine debris, from fragments of artificial fabrics discharged in urban wastewater, and from leaching from land-based waste sites.

Recent scientific research has highlighted the potential environmental impacts of plastic nanoparticles: they appear to reduce the primary production and the uptake of food by zooplankton and fiber-feeders. Nanoparticles of titanium dioxide, which is widely used in paints and metal coatings and in cosmetics, are of particular concern. When nanoparticles of titanium dioxide are exposed to ultraviolet radiation from the sun, they transform into a disinfectant and have been shown to kill phytoplankton, which are the basis of primary production. The scale of the threats from nanoparticles is unknown, and further research is required.

Sewage pollution from ships is mainly a problem of cruise ships: with up to 7,000 passengers and crew, they are the equivalent of a small town and can contribute to local eutrophication problems. The local conditions around the ship are significant for the impact of any sewage discharges.

The dumping of garbage from ships is a serious element of the problem of marine debris. In 2013, new, more stringent controls under MARPOL came into force. Steps are being taken to improve the enforcement of those requirements. For example, the World Bank has helped several small Caribbean States to set up port waste-reception facilities. Other States (for example Member States of the European Union) have introduced requirements for the delivery of waste ashore before a ship leaves port and have removed economic incentives to avoid doing so. It is, however, too early to judge how far those various developments have succeeded in reducing the problem.

Major disasters in the offshore oil and gas industry have a global, historical recurrence of one about every 17 years. The most recent is the Deepwater Horizon blowout in 2010, which spilled 4.4 million barrels (about 600,000 tons) of oil into the Gulf of Mexico. The other main harmful inputs from that sector are drilling cuttings (contaminated with drilling muds) resulting from drilling of exploration and production wells. Those materials can be harmful to marine life under certain circumstances.

The environmental impacts of near-shore mining are similar to those of dredging operations. They include the destruction of the benthic environment, increased turbidity, changes in hydrodynamic processes, underwater noise and the potential for marine fauna to collide with vessels or become entangled in operating gear.
(Excerpted by SU Research and Environmental News Service)


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