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Pollution and biomagnification and its impacts on the marine life

By: Satti Kalyan Reddy

The world’s oceans are a magical, diverse, and abundant ecosystem that mankind needs in order to survive. The oceans cover over 72 percent of the planet’s surface, provide over 97 percent of the world’s water supply and over 70 percent of the oxygen we breathe. Oceans are the principal component of Earth’s hydrosphere, the world ocean is integral to all known life, form’s part of the carbon cycle, and influences climate and weather patterns. Unfortunately, the rapid increase in the number of people living near the coast and the uncontrolled developmental activities are resulting in marine pollution. Pollution is a major problem that has negative effects on the planet’s ecosystems, including the oceans. In many parts of the globe, economic development has been most active in coastal zones, putting enormous pressures on coastal ecosystems. We have so much to thank the oceans for, however, they are threatened daily by natural and manmade pollution.

“Over the last decade, we have produced more plastic than we have in the last 100 years. This sharp increase in plastic entering our waters harms not only marine life but also humanity. Plastic kills fish, birds, marine mammals, and sea turtles, destroys habitats and even affects animals’ mating rituals, which can have devastating consequences and can wipe out entire species. “

In recent decades, pollution of marine ecosystems has gained much attention. Ocean transport of oil, the extraction and processing of offshore hydrocarbon deposits, and manufacturing in refineries near coastal regions, as well as other anthropogenic activities, pose several hazards that can lead to water pollution. Marine (navigation) accidents involving oil tankers or spills from offshore drilling platforms have caused disasters accompanied by huge contamination, with grave repercussions. Marine wildlife faces a growing number of threats across the globe, and the survival of many species and populations will be dependent on conservation action. Now a days the Underwater Sound pollution has also become a major threat for environment. Most marine animals, particularly marine mammals, and fish, are very sensitive to sound. Noise can travel long distances underwater, blanketing large areas, and potentially preventing marine animals from hearing their prey or predators, finding their way, or connecting with mates, group members, or their young. Decreased species diversity in whales and dolphins was related to an increase in seismic noise.

“Biomagnification has insane effects on marine life such as Biomagnification makes marine animals more prone to several diseases and effects on Reproduction and Development of Marine Creatures since the toxic chemicals accumulate in the important organs of aquatic organisms that affect their reproduction and development processes.”

For e.g., the shells of the eggs of the sea-birds are very thin that might get crushed by the birds themselves during incubation. The toxic chemicals, mercury and selenium destroy the reproductive organs of aquatic creatures and destroy the Coral Reefs because of cyanide that is used in leaching gold and fishing, is the main cause of the destruction of coral reefs. Coral reefs are the dwelling and feeding grounds for many sea creatures. Their destruction affects the lives of many aquatic animals and mainly cause disruption of Food Chain because of the chemicals and toxins which are released into the water bodies disrupt the food chain. The small organisms absorb the toxins which are eaten up by larger animals. These toxins, thus, get accumulated in the higher level of organisms.

For this study monitoring data on selected compounds were retrieved from the literature. The following chemicals were chosen due to their environmental relevance as well as the availability of monitoring data (ASMO 1995): Pentachlorophenol (PCP), hexachlorobenzene (HCB), 1,1,1-trichloro-2,2-bis(p-chloro phenyl)ethane (DDT), 1,1,-dichloro-2,2-bis(p-chlorophenyl)ethene (DDE), lct,2a,313,4ct,5ct,613-hexachloro cyclohexane (lindane or “/-HCH), 1,2,3,4,10,10-hexachloro-6,7-epoxy-l,4,4a,5,6,7,8,8a-octahydro-endo,exo 1,4:5,8-dimethanonaphthalene (dieldrine), naphthalene, anthracene, fluoranthene, benzo[a]pyrene, poly chlorinated biphenyls (PCBs), chloroparaffins (CPs), tributyltinoxide (TBTO), cadmium and mercury.

The accumulation of chemicals in fish depends on the aquatic concentration and the bioconcentration factor (BCF), but the respective data have rarely been measured with marine species. Evaluation of the available literature data revealed that the accumulation in marine and freshwater fish differs generally by less than a factor of 10, i.e., within the range of experimental and interspecies variance.

Different oceans have different characteristics, varying in depth, temperature, topography, circulation, etc., varying with depth, temperature, topography, circulation etc., which need to be considered while deducing a suitable model. The Indian Ocean Region (IOR) pose some significant challenges. Its warm temperature renders it vulnerable to climatic fluctuations like monsoons, tsunamis, cyclones, and high winds. Moreover, the tropical littoral waters of the IOR  lead to sub-optimal performance of any kind of sonar, hampering the performance. Additionally, the rich biodiversity in the seas of IOR leads to multiple reflections of the emitted signal causing a complex signal packet at the receiver’s end. Such challenges must be tackled while solving the model to get relevant results.

“The bioconcentration factors in marine species appear to be systematically lower, hence it may be justified to use freshwater BCF data also for hazard assessments for marine ecosystems if the respective measurements are unavailable. Combining the BCF values with toxicity data (no observed effect concentration “NOEC”) for fish yields the critical body burden (CBB), the contaminant level inside the organisms above which the fish will be impaired. CBB=NOEC.BCF “

However, there is a lack of consistent data sets for marine environmental assessment purposes, even for priority pollutants. The existing data from monitoring campaigns are far from being harmonised: Reported pollutant concentrations in environmental media, e.g., fish, are based on wet weight (ww) or dry weight (dw), corrected for lipid content or not, for whole fish or specific organs, muscle etc. Hence, for each compound merely a variety of non-comparable data can be retrieved from the literature. Furthermore, the results of chemical analyses are strongly influenced by the techniques used for sampling, sample storage, extraction procedures, clean-up and the measurement techniques for identification and quantification of the chemicals. Since details on the basic analytical specifications, e. g. recovery rates, detection limits, determination limits etc., are rarely given in the literature and the application of international standard procedures, e.g., US-EPA-, ISO- (international standards), EN- (European standards) methods, is not agreed upon, the available data are not strictly comparable and they might not have the quality necessary to justify regulatory actions. Furthermore, the monitoring of chemicals in the environment is obviously concentrated on those compounds, for which sensitive analytical detection is readily available, e.g., chlorinated pesticides are easily detected with an electron capture detector (ECD) in trace amounts, or mercury and cadmium with atomic adsorption spectro metry (AAS). Other contaminants, more difficult to detect and to determine, are rarely subject to intensive studies even though their impacts on the environment may be even more severe. 

“It’s about time that the world realizes the great potential threat that the marine pollution is causing and we all should join hands along with the government and private entities to make it a success.”

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About The Author

Satti Kalyan Reddy

Satti Kalyan Reddy is a final-year Mechanical Engineering student at IIT Delhi. He is currently pursuing his internship at MRC, Pune.