The uncontrolled use of antibiotics, growth-promoting hormones, pesticides and other disinfectants used for controlling diseases and pathogens in aquaculture in the seven districts, such as Ganjam, Puri, Khordha, Jagatsinghpur, Kendrapada, Bhadrak and Baleswar have serious health hazards on cultured prawns, fishes, human beings, besides the flora and fauna at large.
Antibiotics and disinfectants were found to be used commonly by the farmers. The chemicals used in the culture systems as antibiotics or disinfectants for the culture water, tanks and other utensils have serious health hazards for both the cultured prawns and human beings.
Polyculture in freshwater fish-prawn farms, prawn farms, and rice-prawn farming is the tradition of Odisha coast, especially in the delta regions. With the growing demand in domestic markets as well as in foreign markets, the culture of freshwater prawn has proved its economic importance and become burgeoning business in Odisha coast. The freshwater prawn plays an important role in the economy of Odisha by earning valuable foreign exchange, generating employment, improving the socioeconomic conditions of the backward people. Nevertheless, the biggest problem faced by the farmers every year in this sector is due to the viral, bacterial, or parasitical diseases. The bacterial diseases are treated by different antibiotics to avoid the outbreak of deadly diseases. The quality of the water and soil is always maintained by using disinfectants. A variety of drugs are being used predominantly in different farms of the districts to reduce the attack of the different pathogens, to improve the survival rate and to increase the intensity of feeding leads to better growth rate. The common antibiotics oxytetracycline, erythromycin, chloramphenicol and nitrofurans are commonly used to control the bacterial pathogens successfully. Most of the farms use chloramphenicol followed by oxytetracycline and erythromycin. Besides these antibiotics, the farms use disinfectants, such as formalin, malachite green, potassium permanganate, and methylene blue (MB), to disinfect the water and for parasitical diseases caused by petrichous protozoan ciliates, and some bacterial pathogens.
The antibiotics chloramphenicol (mostly used in the farms) and nitrofurans are banned worldwide for use in the production of foods because of their serious side effects. Chloramphenicol may cause fatal aplastic anemia and nitrofurans are classified as carcinogens. The use of antibiotics for treatment arise various antibiotic-resistant bacteria. The antibiotics used in the prawn farms create health hazards when exposed on the skin or inhaled.
Nirmal Sarkar, a worker working in a aquaculture pond at Sunduripal of Rajnagar told, “We are suffering with skin irritation and respiration problems. But still we have to work there for our bread and butter.”
Similarly, malachite green is a respiratory poison. It is not very soluble in water and binds to sediments. It accumulates in biota but mostly in simple organisms. In fish, malachite green can be found in all organs in great quantities, including kidney. In water, potassium permanganate is quickly transformed into nontoxic manganese dioxide. It is toxic for phytoplankton.
MB has the potential to affect a wide variety of physiologic reactions. Its affects the red blood cells adversely. Paradoxically, at higher doses, this equilibrium is destroyed and an excess of methemoglobin is produced. The formation of hydrogen peroxide as a by product can lead to oxidation of the red-cell membranes, denaturation of haemoglobin, hemolytic anemia, and heinz body formation.
Disinfectants are drained in the local water bodies leading to pollution. The controlling authorities have ignored the laws to control the hazardous drugs. The farms are not using procedures to avoid the introduction of diseases in prawns by regular water quality management, probiotics or other herbal medicines with fewer side effects.
“The export of Vannamei shrimps has grown by leaps and bounds in the past few years. However, there is unregulated growth of aquaculture in Odisha coast which are not following the guidelines,” told Ranjeet Pattanaik, a social evaluator of YARR.
“The use of antibiotics as feed additives in food animals has been cited as one of the reasons for the development of antibiotic resistant bacteria (ARB) in the environment. The use of antimicrobial drugs for treating aquaculture (fish, shrimp etc) is unregulated; antibiotics can be purchased in pharmacies, general stores, and even market stalls .Antibiotic resistance and possible treatment failures in production are becoming a fast growing preoccupation involving diverse agricultural industries and species. The problem is acute in aquaculture industry where resistance development has been reported in freshwater and marine environments,” told environmentalist Dr Saraswat Mishra.
“The consequences of antimicrobial resistance in bacteria causing human infections include increase number of infections, frequency of treatment failures and severity of infection, and finally increased costs to society associated with disease. Increased severity of infection includes prolonged duration of illness, increased frequency of bloodstream infections, hospitalization and mortality,” said Dr Sudhi Ranjan Dash.
(Written under the aegis of CSE Media Fellowship. The previous write-up published on November 23 is also in this series)