Health and Environmental Effects of POPs
Several studies have been conducted on the effect of POPs on human health. Inhalation and ingestion of dust and air has been described as the major source of POPs in humans. An increase in hypertension was reported due to higher concentration of PCBs and organochlorine (OC) POPs in Arctic populations . Langer et al. described diabetic problems in children because of pesticides and PCBs .
Earth’s environment is affected by POPs through biotic, abiotic, social or technological interferences and subsequent degradation of ecological balance. The environmental problems and disturbances in aquatic ecosystems observed in the North Sea, Baltic Sea, Great Lakes and the Arctic Sea during the 1980s and 1990s were attributed to higher POP concentrations in these areas . The effects of POP concentration in living species include shift in sex ratios, impaired fertility, wildlife cancer and various other physical abnormalities. POPs have been found to affect biochemical processes (immune and endocrine systems, reproduction and development) and also impact tissue residue levels in several top trophic level species such as seabirds, polar bears, polar fox and sled dogs [4,24]. Climatic changes have also been observed in food webs, ice and snow melt, lipid dynamics and organic carbon cycling.
One of the important phenomena described by POPs is the “grasshopper effect” involving cyclic volatilization and condensation. These chemicals tend to migrate from warmer climates to colder regions and settle down in extremely cool situations, but evaporate when the temperature rises. The presence of this cyclic migration of POPs contributes to global warming.
Some key properties of POPs control their fate in the environment, and environmental chemists can make reasonable predictions about their fate and behavior based on these. Such properties include aqueous solubility; vapor pressure; partition coefficients between water-solid, air- solid and air-liquid; and half-lives in air, soil and water . However, there are often wide variations in these properties, leading to uncertainties in the precise behavior of these POPs.
The human population as well as industrial and agricultural activities are increasing continuously, which add POPs to the environment. The regulations to control POPs remain limited to reports, research papers and books, especially in developing countries . However, several research studies have attempted to develop models to predict future perspectives of POPs, depending upon their physical, chemical and mechanistic behavior. Application of various modeling tools have been made for assessment of climate change, assessment of risk profiles of POPs, evaluation of ecological risks in populations and aquatic communities and also review of future challenges posed by POPs based on past understandings and increased leaching of POPs from landfills [4,25-27].
The immediate requirement is to develop remediation and control methods for POPs before their menace further worsens. Some important ways to control the increasing POPs concentration across the environment are described as follows :
- • Development of remediation measures by altering the genetic structures of microbes in order to make them capable for bioremediation of POPs.
- • Reduction in the production and use of POPs by application of stringent bans on more harmful chemicals and phasing out usage of others.
- • Development of effective techniques such as adsorption, solvent extraction, alkali metal reduction, incineration, solidification and pyrolysis for removal of POPs.
- • Additionally, more advanced experimental conditions should be developed in electrochemical and membrane technologies to address POPs removal from water resources.