Issue link: https://maltatoday.uberflip.com/i/604914
maltatoday, SUNDAY, 22 NOVEMBER 2015 3 JAMES DEBONO THE amount of potentially harmful mercury in Malta's coastal waters has exceeded the levels laid down in the EU's Environmental Qual- ity Standards Directive, an assess- ment carried out by the Malta En- vironment and Planning Authority (MEPA) has revealed. The report is based on samples taken by different monitoring sta- tions at nine coastal bodies during 2015, all of which registered a "poor chemical status" for mercury. When ingested in seafood in large quantities, mercury can pose a threat to human health, especially to the development of the child in the womb and early in life. The report was published in the MEPA website in September as one of a series of reports related to Mal- ta's Water Catchment Management Plan, an EU requirement aimed at improving the status of Malta's in- land and coastal waters. Mercury in seafood Another report recently issued by MEPA – related to the imple- mentation of the Marine Strategy Framework Directive – reveals that there were "a few occasions where mercury exceeded the permissible levels" stipulated by EU directives in muscle meat of sampled fresh dog- fish, chilled tuna and fresh and fro- zen swordfish. This emerged from tests on sam- ples of fish undertaken by the De- partment of Environmental Health, which regularly undertakes chemical monitoring of fish and other seafood destined for human consumption. In 2011 the Times of Malta had reported that a high concentration of mercury in seafood was the main public health hazard found during "market surveillance" among the 27 cases reported by Malta to the EU's Rapid Alert System for Food and Feed (RASFF). Mercury sources to be investigated One of the measures proposed by the newly published Water Catch- ment Management Plan is the estab- lishment of a Mercury Management Plan to enable the investigation of possible sources of mercury and find ways of reducing its presence in Maltese waters. But Malta has already declared that it will not be able to achieve the parameters set by EU directives before 2021 since it has first to in- vestigate the possible sources of this contaminant, a source which may well be related to industrial activity taking place in other countries. While confirming Malta's "poor chemical status" when it comes to mercury, the MEPA assessment describes mercury as Malta's "only failure" when it comes to the good chemical quality of its coastal wa- ters. Sediments in eight out of nine water bodies around the Maltese coast did not exceed the permissible amount of mercury. The only one exception being the coastal body in the north east of Malta, which in- cludes St Paul's Bay and Mellieha. Various potential sources for the high levels of mercury in Maltese waters are mentioned in the MEPA report. One potential source is the old coal-fired power station which emitted mercury. But this is deemed to be an unlikely source because of low levels of mercury in the sedi- ment except for an area in the north east. The report states that "transbound- ary sources" from other countries al- so need to be investigated, together with untreated sewage formerly re- leased at Xghajra. How toxic is mercury? Mercury is a naturally occurring metal found in the general environ- ment even in the absence of human activities. But fossil fuel combus- tion, especially that of coal, min- ing, smelting, waste incineration, fertilizers, fungicides, sewage and other human activities also release mercury in the sea or the air. All forms of mercury can enter the body and are potentially toxic to humans, depending on the level consumed. In the sea mercury is transformed by bacteria into methylmercury which can accumulate in fish and shellfish. Large predatory fish like sword- fish are more likely to have high levels of mercury as a result of eat- ing many smaller fish that have ac- quired mercury through the inges- tion of plankton. People may be exposed to mercu- ry in any of its forms but exposure mainly occurs through consump- tion of fish and shellfish contami- nated with methylmercury. A significant example of mercury exposure affecting public health occurred in Minamata, Japan, between 1932 and 1968, where a factory producing acetic acid dis- charged waste liquid into Minama- ta Bay. The discharge included high concentrations of methylmercury. The bay was rich in fish and shell- fish, providing the main livelihood for local residents and fishermen from other areas. For many years, no one realised that the fish were contaminated with mercury, and that it was caus- ing a strange disease in the local community and in other districts. At least 50,000 people were affect- ed to some extent and more than 2,000 cases of Minamata disease were certified. Minamata disease peaked in the 1950s, with severe cases suffering brain damage, pa- ralysis, incoherent speech and de- lirium. jdebono@maltatoday.com.mt News Love * Terms and conditions apply getting my VAT back in vouchers * g Mercury in Malta's seas exceeds EU parameters What could be the reason for a poor status in mercury? PROF. ALFRED VELLA, BIOLOGIST MERCURY sources are multiple and controlling the dispersion of this heavy metal is a vexing issue. Coal-burning, cement making, solid waste incineration, smelting of metals and mining are signifi- cant sources of atmospheric mer- cury, ending up in sea water and eventually in the tissue of fish. This means that consuming large fish such as tuna and swordfish, that would have been in longer contact with contaminated water than small fish, would present a risk to human health from the ef- fects of mercury. In the Mediterranean mercury pollution is exacerbated by the presence of cinnabar (mercury ore) deposits in Sicily, which are believed to contribute significantly to pollution of coastal waters. Mercury and its compounds are used in a wide variety of ap- plications (dental fillings, marine antifouling paints, thermometers, batteries), so municipal solid waste sites would also be heavy sources of mercury and its compounds. I suspect that for Malta, the most significant sources of mercury would be the landfills: however, our coastal waters are also likely to be subject to effects from trans boundary aerial mercury contami- nation and trans boundary mer- cury in the water column.