Persistent Organic Pollutants in the Environment

EMEP Status Report 3/2003

V.Shatalov, S. Dutchak, M.Fedyunin, E.Mantseva, B.Strukov, M.Varygina, N.Vulykh, W.Aas, S.Mano

ABSTRACT

The prime object is the assessment of pollution levels in Europe (hereinafter - EMEP region) by polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), g-hexachlorocyclohexane (g-HCH) and by hexachlorobenzene (HCB) with the use of monitoring data from the EMEP network stations and mathematical modelling.

The outcome of studies of the environmental pollution by POPs under EMEP is discussed below:

The official data on POP emissions (PAHs, PCDD/Fs, PCBs, g-HCH, HCB) for 1980-2000 were submitted by 30 countries. During recent years the number of countries providing the data on POP emission totals and their spatial distribution increased. According to the official data and expert estimates, total POP emissions in the EMEP region on the whole tend to cut down. For example, emissions of PAHs (benzo[a]pyrene and benzo[b]fluoranthene), PCDD/Fs and PCBs in Europe decreased from 2 to 5 times in the period from 1980 to 2000.

Thirteen measurement sites have reported POP data to CCC for 2001. Six of these were measuring POPs in both precipitation and air. The number of sites is still unsatisfactory in EMEP and especially in south and east of Europe.

On the basis of measurements, it is estimated that the general trends in concentrations of atmospheric a- and g-HCH and HCB are decreasing since 1991. The concentration of benzo[a]pyrene (and other PAHs) shows a clear seasonal variation, with peak concentrations during winter. The concentration level is decreasing towards the north of Europe.

The trend analysis of POP accumulation in the main environmental compartments shows that the rate of POP soil content variation lags emission reduction rate. For instance, PCDD/F emission decrease 4.5 times from 1980 to 2000 results in a moderate (by 4%) reduction of soil concentration. The concentration decrease of the considered POPs in air and seawater also lags the emission reduction rate.

Calculations covering a long period of time allowed evaluating the levels of pollution by POPs in Europe in 2000. Substantial levels of PCDD/F pollution are specified for the Czech Republic, Belgium, Switzerland, Luxembourg, Slovakia and Italy. High concentrations of benzo[b]fluoranthene in the main environmental media are characteristic of polluted territories of Central Europe and Russia. In some regions of Poland, Germany, and the Czech Republic mean annual air concentrations of benzo[a]pyrene (B[a]P) are higher than 1 ng/m³. B[a]P mean diurnal concentrations can exceed mean annual ones as much as 5 times (and more). The assessment of B[a]P and PCDD/F depositions to regional seas is also available. The most intensive fluxes are over the Baltic Sea and least intensive - over the Mediterranean Sea.

POP transboundary transport significantly affects the level of pollution in the European region. On the example of B[a]P, it is demonstrated that in the majority of countries the contribution of transboundary transport to air concentration and deposition levels is from 30 to 70%. B[a]P transboundary transport is analyzed in detail for all Parties to the Convention and its input to the pollution in different parts of a country is estimated.

Along with the evaluation of POP levels in Europe the long-range transport potential of PCDD/Fs, PCBs, g-HCH and HCB is investigated. The transport distance of these POPs is from 5000 km (some congeners of PCDD/Fs) to 10000 km (HCB). An essential fraction of POP emissions from European sources can be transported beyond the EMEP domain. Pollution levels in the Northern Hemisphere are evaluated (on the example of PCBs and g-HCH). High levels of PCB pollution are found in some regions of West Europe and the US eastern coast. High g-HCH concentrations and depositions are estimated in some regions of West Europe and southeastern Asia.

POP intercontinental transport can make a noticeable contribution to the contamination of the Northern Hemisphere, in particular to the Arctic. On the example of PCB-153, it is shown that the main contribution to the Arctic contamination (approximately 60%) is made by European emission sources. The combined input of African and Asian sources is about 10% of PCB-153 total depositions to the Arctic area.

This year at the meeting of Expert Group on POPs (the Working Group on Strategies and Review) a model approach for the evaluation of the long-range transport potential and overall persistence in the environment of new substances (potential candidates to the Protocol on POPs) was presented. This approach has been tested for a number of new species (hexachlorobutadiene, pentachlorobenzene, polychlorinated naphthalenes, a-endosulfan and dicofol). Among the considered compounds hexachlorobutadiene and pentachloro-benzene are mostly apt to the long-range transport. PCN-47 (congener from the group of polychlorinated naphthalenes) is most persistent in the environment. The investigation results can be used for making a decision whether it is reasonable to incorporate new substances to the Protocol on POPs.

Studies, which could be beneficial for the development of the effect-based approach for the evaluation of POP impact upon the environment, are underway. The POP contamination and accumulation dynamics in different environmental compartments are estimated. The calculation results make it possible to identify the main medium accumulating the bulk of this or that pollutant mass in the environment. According to model estimates, 90% of PCDD/F overall toxicity accumulated in soil. High concentrations in soil are found in the majority of European countries. A model approach to the evaluation of POP deposition fluxes to various types of underlying surfaces is under development.

The co-operation with national experts of Parties to the Convention is keeping on. MSC-E started the intercomparison study of POP models describing the behavior of POP in the environment. Experts from Canada, the Czech Republic, Denmark, France, Germany, Japan, Norway, Switzerland, the United Kingdom, and the USA are taking part in the comparison of models.

The assessment of environment pollution by POPs was carried out in close co-operation with international organizations and programmes (UNEP, AMAP, HELCOM, WMO). The main results were presented for the discussion and examination at a number of international conferences, workshops, and expert meetings.
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