Comprehensive Multi-compartment Sampling for Quantification of Long-Term Accumulation of PAHs in Soils.

Long-term accumulation in the soils of ubiquitous organic pollutants such as many polycyclic aromatic hydrocarbons (PAHs) depends on deposition from the atmosphere, revolatilization, leaching, and degradation processes such as photolysis and biodegradation. Quantifying the phase distribution and fluxes of these compounds across environmental compartments is thus crucial to understand the long-term contaminant fate. The gas-phase exchange between soil and atmosphere follows chemical fugacity gradients that can be approximated by gas-phase concentrations, yet which are difficult to measure directly.

Legacy pollutants in fractured aquifers: Analytical approximations for back diffusion to predict atrazine concentrations under uncertainty.

We present novel analytical approximations for the estimation of travel distance and relative height of solute concentration peaks within a single fracture system for pollutants that have been temporarily applied at a constant rate in the past. These approximations are used to investigate the spatiotemporal evolution of the concentration of atrazine, as an example for many other so-called legacy compounds that are still found in the groundwater of fractured rock aquifers even decades after their application has stopped. This is done in a stochastic framework to account for the uncertainty in relevant parameters, focusing on probabilities of exceeding the given legal concentration limit and the expected length of the recovery period.