Environment toxicology is the field of study which deals with the study of pollutants, their impact and effect on the physical environment. Toxicology basically looks for understanding the toxins or poisons and their effect. It involves an investigation of physical, biological, chemical factors along with the adverse effects that it poses to the ecosystems and other living organisms. The toxins can either be manmade or natural.
WHAT ENVIRONMENTAL TOXICOLOGY IS ALL ABOUT
- It incorporates fields like microbiology, ecology, molecular genetics, geology, limnology, chemistry etc. in order to find the pollutant.
- Environmental toxicology is dealing with pollutants in order to find the way they interact with the environment, living beings, plants etc to leave any effect.
- The environmental toxicologists investigate the root cause of the problem, the pollutant and then eliminate them.
- The samples for examination are collected from soil, air and water.
- It is further divided into two subcategories-
- Environmental health toxicology which deals with the study of detrimental effects of chemicals/ toxins on human health.
- Ecotoxicology which deals with the study of detrimental effects of toxicants on the wide range of organisms that ranges from microorganisms to predators in various ecosystems.
ENVIRONMENTAL TOXICOLOGY AND AQUATIC ECOSYSTEM
Various environmental toxins enter the aquatic ecosystem and lead to detrimental effects. The intermittent exposures cause aquatic toxicity problems like spray-drift, run-off, death, disruption in the food chain etc. Insecticides can enter the aquatic ecosystem directly or indirectly. Pesticides tend to enter the aquatic systems indirectly by the use of water, wind and feed.
The aquatic ecosystem thriving near agricultural regions suffer the most burn off the toxins. They are exposed to the wide range of insecticides, pesticides and other toxins that can harm marine life species. Some toxins get dissolved in water, some bind themselves to the aquatic food while some are directly ingested by the marine animals.
In order to safeguard the aquatic ecosystem, it becomes vital for the individuals to take initiative and prevent toxins from entering the aquatic ecosystem. The humans who consume the affected aquatic animals also get affected by those toxins. There can be health issues faced by both- aquatic animals and humans.
For instance, sulfuryl fluoride is an insecticide that breaks down sulphate and fluoride on reacting with the environment. Fluoride acts negatively with the aquatic wildlife by altering the balance, lipid levels, proteins etc of the fishes. Cyprinus carpio faces improper growth, feeding inefficiency owing to the release of this toxin. They face problems in body composition and other biochemical processes.
Environmental toxicity is cited to be one of the major reasons behind marine mortality in the last twenty years. For instance, in the 1980s, more than 1800 harbour seals faced death in regions of Baltic sea, Irish sea, North sea etc. due to exposure of phocine distemper virus. It was found that their tissues had high levels of polychlorinated biphenyls present.
TOXICOLOGICAL EFFECTS OF PYRETHROIDS ON THE AQUATIC INSECTS (NON-TARGETED)
Pyrethroids are the insecticides that have low dose application rates, high biological activity, are photolabile and have strong sorptive properties. These are used in agricultural and aquatic systems in order to control insects and pests. They cannot dissolve easily in water which causes an imminent threat to the non-targeted aquatic animals. The use of pyrethroids comes with increased sensitivity towards aquatic ecosystem. The toxin can disrupt various predator-prey relationships which are beneficial for the ecosystem to thrive.
They cause extreme toxicity to the aquatic ecosystems and hence they cannot be widely used in agriculture. The aquatic animals can face death from the use of minute quantities of pyrethroids also. In the United States, the registration of new pyrethroids has come under scrutiny owing to their high toxicity.
Pyrethroids residues can be bioavailable easily when they are suspended in water rather than being absorbed on particulates. This increases the intake of toxins by the marine life species. In addition, the marine life species get disturbed by the toxins bound to food. Different aquatic animals respond differently towards the toxin (pyrethroids) and hence it becomes important to cease its use.
IN SHORT (ABOUT PYRETHROIDS)
The aquatic animal shows high sensitivity towards the use of pyrethroids. It is critical for the aquatic animals to show susceptibility of the pyrethroid insecticides. The toxin can enter the food chain and alter the relationship between various prey-predator relationships in the ecosystem. There is research work going on to fully comprehend the relationship between pyrethroids toxicity and the use of insecticide.
They can enter the aquatic ecosystem directly through the use of pyrethroids for vector control. They can also enter the aquatic ecosystem indirectly through erosion, spray drift and runoff. The environment toxicology of pyrethroids needs to be understood in order to safely use them near aquatic environments.