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This is an oil tanker that could release little amounts of oil by accident and you could see the weathering on the outside of the ship where it's painted.

Shipyards

Shipyards, or dockyard, are places where ships are built, repaired or scrapped and can vary in types from yachts to military vessels, cruise liners, or tankers. Shipyards can be found in every country around the globe and can help in many ways like boost the economy by providing jobs to its citizens. For example, the U.S. Department of Transportation's Maritime Administration (MARAD), found that the U.S. shipbuilding and repair industry alone supports jobs in all 50 states with a total of more than 110,000 jobs nationwide and contributes $37.3 billion dollars to the national GDP (MARAD,2015).

Pollution

Having shipyards that have been operational for a long time could lead to serious pollution to the environment as years pass by. There have been many different studies that have shown that welding, sandblasting, paint, and maintenance are some of the many factors that contribute pollution to the environment. 

Maintenance

It is common for a ship to have a hull made of steel, but this process must go through many layers of anti-fouling or anti-corrosion paint to ensure that the metal doesn't corrode and prevent organisms from attaching to the surface. The painting process is inevitable but will it be at nearly every shipyard there is, and two of the most common ways to paint a ship is by airtight spraying and thermal spraying. Many studies have shown that painting is what generates almost half dangerous waste at a shipyard due to using high-pressure equipment to wash or remove any unwanted material that is on it like rust. Which will eventually make its way to the water and creates water pollution to the environment. Once these have compromised the surface of the hull the ship must go to the shipyard for maintenance. In a study in 2011 samples of sediments were collected from two sites in coastal marine area of Yongho Bay, one from the shipyard yard and the other 500m away (Jin Young,2014). These results had analyzed that both samples contained metals that included Al, Fe, Li, V, Cr, Mn, Ni, Cu, Zn, As, Cd, Sn, and Pb (Jin Young,2014). In addition, it had been confirmed that the concentration was higher in the first sample that was by the shipyard then the sample taking 500m away and was due to paint fragments applied to the steel ship hulls (Jin Young,2014).

Solutions  

After a ship has been used it is then scraped at a shipyard, but in the process can release excessive amounts of pollution. In paint used for hulls of the ship, they are anti-fouling based paint. Over time weathering from ships will eventually sink to the bottom of the seabed and the most common component that is toxic in paint used in shipyards is triphenyl (TPT) and can be treated by using dolomitic sorbents. In 2005, there was a study that show the high level of toxicity of TBT compounds to organisms in the ocean and what can be done to reduce the pollution by using dolomitic sorbents (Walker, 2005). In the study, a sample of shipyard water was used in the experiment in a period over 14 days (Walker, 2005). At the end the experiment it was concluded that dolomitic and dolomite were successful in reducing the contaminants from the shipyard wastewater (Walker, 2005).  

Welding

Welding is the most important factor in ship building and should be performed by qualified welders in order to protect the ship structure. It is achieved by heating the surfaces to the point of melting using oxy-acetylene, electric arc, or other means, and uniting them by pressing, hammering, etc. But in shipyards, there are times when the welder has to crawl into a confined space and weld. Welding can produce toxic fumes such as Nitric Oxide, Nitrogen Dioxide, Carbon Monoxide, Phosgene, Hydrogen Fluoride, Carbon Dioxide can also result in serious damage to human health or death if ventilation is not present. It can also A case study was performed to see where would be most effective place exhaust the hull cells on the bulkhead in between two spaces using an air horn versus air with an electric blower (Wurzelbacher,2002). They used welders that were employees of the shipyard and asked them to weld in a specific space. One that had shipyard dilution ventilation(DV) and the other had local exhaust ventilation(LEV) then recorded to see which typed of ventilation worked the best (Wurzelbacher,2002). In the results, they found that local exhaust ventilation reduced particulate concentrations but also the efficiency of either method depended on equipment maintenance and their own work practices because everyone has a different way of getting things done (Wurzelbacher,2002).

References