Towards a complete mass balance and model for PCBs and PAHs in a small rural lake, Cumbria U.K.

Abstract

This paper summarizes the processes of exchange/fluxes for polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in a small well-studied rural lake, Esthwaite Water in northwest England. Measurements of PCB and PAH concentrations have been made in rain, air, water, dated sediment cores, and sediment trap samples over a 2-yr study period and used to determine fluxes to and from the lake. A steady state mass balance model was used to construct an input-output budget for the chemicals and to investigate the relative importance of transport into and out of the lake. The hydraulic transport from the lake was the most important loss mechanism for both PCBs and PAHs. Volatilization, not sedimentation, is currently the dominant loss process for PCBs in the water column, whereas, sedimentation exceeds volatilization for PAHs. The data further suggest that the current sediment-water flux is upward for PCBs and downwards for PAHs, indicating that the sediments might be acting as a secondary source for PCBs but continue to act as a sink for PAHs. Riverine, catchment runoff, or both are believed to be the most important input for PCBs and PAHs to the lake although direct aerial deposition to the lake is also important for PCBs. Differences in the mixtures of compounds in the various compartments suggests significant fractionation of PCBs and PAHs in the air-water-sediment system in the lake.

Evaluation of sequentially-coupled POP fluxes estimated from simultaneous measurements in multiple compartments of an air–water–sediment system

“…The resulting average sedimentation rate for the core is thus 4.14 ± 2.96 g m -2 day -1 . This rate is comparable to sedimentation rates reported from lakes in the UK (Sanders et al, 1992;Gevao et al, 2000) and in the Great Lakes region in the US (Schneider et al, 2001;Pearson et al, 1997;Baker et al, 1991).…”

Measurements of polycyclic aromatic hydrocarbons at an industrial site in India

“…PAHs can persist in the environment and they have ability to be transported over long distances (Aamot et al 1996;Halsall et al 2001) they are mainly concentrated to urban and industrial zones, but can also be found in rural areas (Gevao et al 2000;Garban et al 2002) or even in remote regions (Kallenborn et al 1998;Migaszewski 1999). Elevated levels of site specific PAHs are generally found near emission sources and they have been measured extensively during the last few decades in environmental samples, especially in atmospheric particles (Halsall et al 1994;Smith and Harrison 1996).…”

Atmospheric pollution histories of three Cumbrian surface waters

“…More recent pollutants include radionuclides, notably caesium‐137, owing to atmospheric weapons testing and reactor accidents (Beresford et al. , 1992), and organic contaminants such as polychlorinated biphenyls and polycyclic aromatic hydrocarbons (Gevao, Hamilton‐Taylor & Jones, 2000).…”