Trinidad: “High cancer risk” with seafood harvested from heavily-industrialised west coast areas

Trinidad: “High cancer risk” with seafood harvested from heavily-industrialised west coast areas
People fishing off a wreck in the Gulf of Paria.
People fishing off a wreck in the Gulf of Paria.

(TRINIDAD EXPRESS) — A first-time Caribbean study, coming out of the University of Trinidad and Tobago (UTT) and The University of the West Indies (UWI), has claimed that seafood harvested from heavily-industrialised areas of Trinidad’s west coast presents “a high cancer risk to the human population”.

Conducted by Aaron Balgobin and Natasha Ramroop Singh, of UTT and UWI, respectively, the report has suggested “remedial action” to lower risks to the population from polycyclic aromatic hydrocarbons (PAHs) present in marine life in western coastal areas, particularly the environs of Port of Spain and Pointe-a-Pierre.

The study further warns of increased risks in these areas during the wet season and, while suggesting that the data contained could inform policy makers, also suggested that “remedial action is needed in this area, such as controlling PAH emissions from their sources”.

Balgobin and Ramroop Singh’s peer-reviewed work, “Source apportionment and seasonal cancer risk of polycyclic aromatic hydrocarbons of sediments in a multi-use coastal environment containing a Ramsar wetland, for a Caribbean island”, was also published in the international journal, Science of the Total Environment. The document notes that “this is the first such study analysing the carcinogenic risks from coastal sediment to the population of a Caribbean island”.

The United States Environmental Protection Agency (US EPA) classifies 16 PAHs as priority pollutants due to potentially toxic, mutagenic and carcinogenic properties. PAHs are a group of more than 100 chemicals also called polynuclear aromatic hydrocarbons, which are released from burning coal, oil, gasoline, trash, tobacco, and wood. Local environmentalists, including Fishermen and Friends of the Sea (FFOS), have for several years claimed that PAHs and other hazards related to the petrochemical industry have caused fish kills in the Gulf of Paria and along the south-western coast.

This was disputed by Government, which said independent tests showed local seafood to be safe.

Seasonal risks

According to the UTT/UWI report, “The mean Incremental Lifetime Cancer Risks (ILCR) due to fish consumption from this region during the dry and wet seasons was N1 × 10−4, indicating a high cancer risk to the human population.”

Balgobin and Ramroop Singh further stated: “In addition, there is a high cancer risk to the general population via sea-food ingestion from this area during the dry and wet seasons… The wet season cancer risk was generally higher than the risk for the dry season. Near-shore sediment posed a greater cancer risk than offshore sediment due to the higher concentration of PAHs from terrestrial sources.”

The researchers used a “dietary ingestion model” to assess human cancer risk using sedimentary PAHs.

The study noted that areas examined were of interest “due to the presence of industrial, urban and shipping activities situated alongside a protected wetland site on the west coast of Trinidad”, referring to the Caroni Swamp, an internationally-protected Ramsar site.

It notes the presence of petrochemical plants at Point Lisas, which utilise natural gas as a feedstock for ammonia, urea, melamine and methanol production, along with iron and steel plants.

“All these activities predominate on the west coast of Trinidad, where therein lies the Caroni wetland (a protected wetland) in close proximity to the capital city of Port of Spain and a natural oil seep site at La Brea, which is the largest deposit of asphalt in the world,” the study noted.

Multiple PAHs source

It was found that gasoline and diesel fuel combustion are the major sources of PAHs found in sediment.

The report further asserts that local seafood ingestion exposes 14 per cent of the population to adverse health risks annually and that “the population is exposed to high cancer risk from fish consumption”.

PAHs were quantified in sediments during the dry and wet seasons and were observed to be significantly higher in the wet season compared to the dry season, Balgobin and Ramroop Singh found.

“Also emerging from this study is that PAH levels were lower in the areas where natural gas is the dominant energy source for industries, compared with those areas where crude oil-based fossil fuel is predominantly used,” the study stated.

“It was observed that near-shore sediment PAHs concentrations were higher than offshore levels.”

The sources of PAHs, identified by Positive Matrix Factorization (PMF) in the marine sediments, were “vehicular combustion of gasoline and diesel, biomass burning, industrial combustion and oil spills”, the report said. The researchers have suggested that the results “can be utilised for developing an effective environmental management policy for coastal areas in Trinidad and the wider Caribbean region, given that much of the islands’ populations depend on the coastal regions for seafood”.

“In addition, these results may assist in boosting current efforts of policymakers, towards phasing out crude oil-based fossil fuels for cleaner energy sources, such as compressed natural gas,” they stated.

Contacted yesterday, FFOS secretary Gary Aboud said the study’s claims have come as no surprise, as the organisation continues to witness fish kills on Trinidad’s west coast, which it believes to be a result of consistent petro-chemical pollution.

“We would want to call on the leader of the nation, Prime Minister Dr Keith Rowley, to declare an environmental state of emergency in the Gulf of Paria,” Aboud said.

“What is happening in the Gulf is cause for immediate, unrelenting remedial action and we urge the Prime Minister to, for now, turn away from the notion of development in traditional terms of highways and buildings, and invest in the health of the environment and therefore the health of the people of this country.”

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