Seasonal trends - pollutants

Motelay-Massei, A., Hamer, T., et al. (2005) Using passive air samplers to assess urban-rural trends for persistent organic pollutants and polycyclic aromatic hydrocarbons. 2. Seasonal trends for PAHs, PCBs, and organochlorine pesticides. Environmental Science and Technology, 39(15) 5763-5773. 

The spatial distribution of the anthropogenic markers derived from each industrial branch was reproducible through all sampling campaigns. However, no preferred seasonal trends according to the distribution patterns of each compound were observed. The pollution of the upper reaches was on average much smaller than in the downstream area. 

Wet deposition may be an important source of PCBs to the Great Lakes. Unfortunately, like dry particle deposition, it is difficult to measure directly because of the low PCB concentrations, the problem of sampling artifacts, and the distribution of rain and PCB concentrations over space and time. Some trends are evident, however [ 189]. Snow has been shown to be much more effective than rain in scavenging PCBs from both vapor and particulate phases at a site in Minnesota [190,191]. This leads to a seasonal effect, in that precipitation concentrations of PCBs are highest in the winter in Chicago (Hites, personal communication), as with the concentrations of many other persistent organic pollutants [192], Possible reasons include sorption to an aqueous or... 

Prevedouros, K., Brorstrom-Lunden, E., et al (2004) Seasonal and long-term trends in atmospheric PAH concentrations evidence and imphcations. Environmental Pollution, 128(1-2) 17-27. 

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