1. How do shifts in weather patterns such as frequent freeze-thaw cycles, drought, and heavy rainfall affect the magnitudes and rates at which colloids, particulate organic carbon, pathogens and chemical contaminants are released from soils and into waterways?
A:The contaminant pathways, e.g. volatilization, adsorption, hydrolysis, biodegradation, photo degradation, photo-enhanced toxicity, uptake and metabolism are altered by climate change, the rates of some of these processes increase with increasing temperature.
Temperature has a direct effect on degradation of litter and therefore, in the metal release, and decomposing plant tissues may be either a source of metals, or sink through adsorption on litter
Emissions of organic pollutants from stocks (e.g. PCBs present in buildings and electrical equipment) will increase with a warming climate because volatilization of chemicals increases exponentially with temperature.
The environmental fate of organic pollutants at the global scale will be affected by many factors related to climate change. The main effects are:
· Increased mobilization of organic Pollutants from environmental reservoirs (soils, glaciers, Arctic Ocean) by increased temperature, extreme weather events such as flooding and increased erosion.
· Increased airborne transport to locations downwind of main emission areas because of higher wind speeds (mainly relevant to the regional scale)
· Enhanced degradation of organic pollutants (under the assumption that higher temperature leads to higher degradation capacity of microorganisms), but also increased formation of potentially organic pollutants like transformation products.
Several studies have addressed the global organic pollutants distribution, reporting temperature as one of the most relevant variables influencing both emission rates from primary and secondary sources, particle–phase partitioning, reaction rates (biodegradation, oxidation), air–surface exchange (volatilisation), air–soil exchange (deposition) and hydroxyl radical formation.
Other parameters related to organic pollutants’ environmental distribution are quantity, quality and spatial variation of precipitations. These climate parameters associated with various climate patterns would also affect scavenging by absorption to snow and hence transport and deposition of organic pollutants.
The loss of permafrost alters the existing biological...