EATING FISH AFTER OIL SPILL, IS IT SAFE?

Fish is a great source of protein and vitamins, it also contains Omega 3 fatty acids. These fatty acids have great health benefits, as it helps reduced heart rate and blood pressure. Altogether fish can be described as a nutritious and healthy food source. However if fish are severely contaminated by oil, both its health and nutrition benefits can be greatly diminished. In cases of oil spills the integrity of available seafood becomes an issue. To ensure public safety, tests and monitoring of seafood is done to avoid health problems. In extreme cases fishing at certain contaminated sites are  temporarily restricted. Fish species can be found in various parts of the water column. As oil sinks to the sea floor via this water column there is a chance for its contact with many fish along the way. Some species that are very susceptible are those that are scavengers and feed on anything including hazardous oil constituents. These species may be feed on by other fish transferring hazardous substance stored in their tissues. As human beings at the top of the food web it is highly likely for us to consume one or more of these contaminated fish.

photo 1* Showing coastal area restriction for fishing. Restriction may be on commercial or recreational fishing.

Oil spills affect fish in two known ways

Taint

 Oil leaves fish “tainted” having characteristics such as :-

1. Possessing an oily smell
2. Having a discoloured appearance
3. Having a rubbery texture when touched

Although tainted meat is not fit for consumption it has no known adverse health effects.

photo 2*  Showing fish covered in oil. This .fish can be considered tainted.

Polycyclic Aromatic Hydrocarbons

Oil can also leave fish with Polycyclic Aromatic Hydrocarbons in their tissue.These hydrocarbons are cancer causing to humans if consumed in the right amounts over a certain period of time. Also studies have shown that certain PAH (example Benzo[a]pyrene can affect pregnant women causing negative birth effect such as premature birth, hindering heart development and asthma in childhood years.

Photo 3 Showing structure of Benzo[a]pyrene a carcinogenic hydrocarbon.

It is possible to eat fish with PAH’s if its level is within the threshold range for consumption. The process to determine if exposed fish containing PAH is safe to eat is called a Risk Assessment.


   

In recent times, one of the biggest oil spills, was the Deepwater  Horizon OIl spill that ocurred in 2010. The Louisiana fishing industry was seriously impacted by the spill and residents there believe that it still is. They based their judgement on the lack of fishing done in the area and the selling of businesses that  once sold fish produce. Also, they claimed that many people are continually leaving the area. They now describe the area as lifeless in comparison to times when there was non-stop activity. 

References
https://www.theguardian.com/environment/2015/apr/18/lousiana-bp-oil-spill-five-years-not-going-back-to-normal

http://www.toxipedia.org/display/toxipedia/Polycyclic+Aromatic+Hydrocarbons

http://blog.nus.edu.sg/lucastange3246/author/lucastan/page/2/   photo 2 *

http://www.scpr.org/news/2015/06/09/52305/santa-barbara-oil-spill-shoreline-75-percent-clean/      photo 1 *

http://bodyecology.com/articles/oil-spill-fish-safe-to-eat.php

http://seafood.oregonstate.edu/.pdf%20Links/Evaluating%20the%20Risks%20for%20Peple%20Who%20Eat%20Fish%20and%20Shellfish.pdf
http://www.sanichem.com.my/hydrocarbons.html    Photo 3 *

A Closer Look At Dispersants

In this article, I intend to give the reader a somewhat comprehensive understanding, on what a dispersant is, so they can develop their own opinion on its use.Information on the history of its use, goes as far back as the 1970's. However as time went by such investigations were reduced. Despite this decline, investigations that were done focused on ecological impact. These investigations can be deemed as limited, since they emphasized more on coastal ecosystems, rather than those offshore.

Photo take from NOAA 2016

However when using dispersant, it should be noted that different methods of its application is done. Methods of its application include spraying from vessels, small airplanes and even helicopters. Simply making contact with oil does not cause dispersion; energy has to be used to create motion. Agitation facilitates the mixing of oil and dispersant, breaking up of the oil particles. However too much or too little energy from wave action is not optimal for the breakdown process. It was found that medium energy waves get the job done. Dispersants is one of many methods used to clean up oil spills. Others include allowing the oil to break down naturally and the use of Booms and Skimmers. In the hierarchy of methods used, the dispersant method was the final option.

Photo take from NOAA 2016

One may wonder why it is placed so low. I think it is based on the fact that its toxic nature, with regard to organisms, is not fully understood by anyone. This usually leads to varying opinions. In a previous article of mine, dispersants were described as being “as harmful as dish soap” and there were persons that would disagree with this statement. I also mentioned that the long term effect of dispersants on organisms was unclear. This is so because more attention is always given to its short term effects. There is significant information on the acute effects on fishes by dispersants derived from studies done in the past. One such study looked at the toxic effects on fish, by dispersant, oil, and dispersed oil. Of the three, dispersed oil ranked the most toxic followed by oil then dispersant alone. There is another study that could explain why dispersed oil may be the most toxic. This study indicated that breaking up oil exposes more of its harmful compounds. However the results from the study also showed variation in some cases, for example a particular species of fish was not affected at all by dispersed oil, but was negatively impacted by oil alone. Therefore it can be stated that dispersed oil may be toxic or non toxic based on species susceptibility. Another factor was the type of dispersant used, toxicity varied with dispersants. Corexit 9500A dispersed was found to be more toxic than JD2000 dispersed but less toxic than SPC1000 as it related to fish species tested. 

Photo take from NOAA 2016.     Image showing oil that reached coastline. Dispersant are used to try to prevent this.                              

In summary, my findings showed that while most dispersants were found to be toxic, there was some exceptions. Beside its toxicity con we must also remember its pros. The most important being the protection of our coastal areas with its ecosystems and how it facilitates our human activities (fishing, recreation, swimming).

References

Maya, Hutchins. 2012, “Effects of Oil Spill Dispersants on Marine Organisms.” Environmental Science Program, Appalachian State University, Boone, NC.  Retrieved from

NOAA 2016. “Dispersants: A Guided Tour.” Office of Response and Restoration Retieved from

Retrieved from

Dead Fish In The Gulf Of Paria

A large number of fish was found floating in the Gulf of Paria, it was estimated to have been in the thousands. However speculation still surrounds what actually caused the fish kill. Information from the Environmental Management Authority and Institute of Marine Affairs claimed that the dead fish was simply a dumped catch by fishermen. The agencies back up their claim, indicating that red marks on the fish was made by fish net. The Secretary of Fisherman and Friends Gary Aboud had a different opinion on the matter. He believed that the deaths were caused by a dispersant Corexit used in the past to clean up a 2013 oil spill (Sharlene  Rampersad 2016).  The Secretary further supported his claim stating that “This area where all of the dead fish are is the exact same area the Corexit was used”. Dispersant is used in oil spills to remove them from the water surface to the subsurface. This is done so that surface oil does not reach the coastline where some ecosystems exist. These ecosystems benefit in a tradeoff with ecosystem in the deeper marine areas where sunken oil with dispersants settles. Despite Mr Aboud’s given reason for the fish kill, in an earlier article it was mentioned that Corexit was as toxic as dish soap (David Kirby 2013). Such a statement can discredit the cause put forward by the Secretary. Looking at the time period in which the dispersant was used and how it relates to the present fish kill was also questionable. The long term effect of dispersant on water dwelling organism is not certain, as was stated by the Environmental Protection Agency. Therefore it is indefinite on what was the actual cause of the fish kill.

I believe this occurrence, apart from the dispute of the cause, shed light on how an oil spill, can result in the introduction of other allegedly harmful substances into the environment, that may negatively impact fish populations.

Photo by: RISHI RAGOONATH

References

 Sharlene, Rampersad. 23 July 2016, " Aboud: Fresh fish Kill in Gulf." The Trinidad Guardian Newspaper,    Retrieved from http://www.guardian.co.tt/news/2016-07-23/aboud-fresh-fish-kill-gulf. Accessed 29th      September 2016.

Kirby, D. (2013, April). A Deadly Paradox: Scientist Discover the Agent the Agent Used in Gulf Spill Cleanup is Destroying Marine Life. takepart.

Retrieved from http://www.takepart.com/article/2013/04/24/corexit-bp-deepwater-horizon-oil-spill-effects-marine-life