Introduction: Persistent organic pollution and its treatment

With the development of chemical technologies before and during the World War II, the spectrum of artificial chemicals produced in increasing amounts by man, was enhanced by a group of persistent organic pollutants (POPs), which became widely manufactured and used substances in the following three decades.

In 1970s, when the awareness rose and environmental science at least partially caught its breath to catch up the production, it was already partially late. Millions of tons of substances wee spread in the soil, water and air, whose real impact on nature and man had not been studied and objectively assessed yet. It took years of research and efforts to stop the runaway production machinery and the use of all suspicious substances. Meanwhile, the POPs, whose decomposition is carried out only very slowly, often in the tens to hundreds of years, started to live "its own life". Mankind was surprised by observing by which way and where the hazardous substances can appear and accumulate, and what effects they can cause before they finally undergo their fate.

Gradual bans of the production and use of substances with proven or only the expected negative impact on human health and the environment, in some cases, tipped up in a blind struggle, which could be ineffective and sometimes even dangerous. One extreme began threatening to tip over into another without an objective insight but also detached view, which could be brought only by serious scientific approach. Only a detailed knowledge of all aspects of the problem, starting with the chemical nature, properties and behavior of the substance in the environment, its dangerous up to toxic properties as well as its ultimate fate may lead to a real appreciation of the risks and propose appropriate measures.

The most important result of these efforts was the Stockholm Convention, which defined twelve most dangerous substances (or their groups) whose production and use must be either eliminated, restricted or strictly controlled. Eleven more substances and their groups were added consequently and it is expectable, that further products will follow.

Stockholm Convention was signed by 128 parties in 2001 and entered into force in 2004, which meant a turning point in the current approach to the POPs all around the world.

The era of mindless production and use, as well as the revolutionary period of prohibitions and restrictions ended, but POPs are persistent and their presence in the environment did not cease by the signing of the Stockholm Convention. The POPs, although their amounts have been still slowly decreasing in general, are still present in the air, which we breathe every day, in the water we drink and food we eat and will be present for several more generations. It is not easy to say, whether the POPs in the environment can mean a real danger, or how highe the danger is, without a detailed and reliable analyses of the situation, which has still been under the development.

For evaluation of its effectiveness, the Conference of the Parties of Stockholm Convention established an arrangement to provide itself data on the presence of the listed chemicals as well as their regional and global environmental transport in the frame of Global Monitoring Plan (GMP) which provides information on the effectiveness of its implementation in order to identify changes in POPs concentration levels over time. It is based both on the transfer of data from existing monitoring programmes and new capacity-building activities.

While the length of the time series rises due to amounts of data from quality equipment in the monitoring networks, the knowledge about its processing, assessment and obtaining trustworthy results, which only may serve as a reliable basis for a discussion on the use of persistent chemicals and their impact, is still rather low.

This publication is partially based on the standard GMP methodology and provides a brief insight to a set of approaches that can be used for processing of the POPs monitoring data to obtain better interpretable characteristics. It should introduce, how to draw conclusions about POPs behaviour in the environment or estimate future developments. It guides the user through eight steps of POPs data analysis and facilitates employing the methods, which can can be applied to other datasets.

There are practical interactive examples based on real POPs data in this publication, which work with R statistical software and its package Shiny. Short R code demonstrations are also given to examine all the methods on your own. Most of the examples use functions from the R package genasis, which was developed in order to provide a wide set of functions used in the POPs data assessment. Both packages and the R software itself are available on the R project web page.

Show methodology Hide methodology of interactive examples

In all examples you can try several selected functions of the R package genasis with basic settings. There is a model dataset kosetice.pas.openair taken from the package, which contains 4-year long time series of passive air sampling in the Kosetice observatory (Czech Republic) for thirty compounds (PAHs, PCBs, OCPs).

In every example you can also input your own values of concentrations in the form of real numbers separated by commas (with dot as a decimal separator). In this case no assumption about the data distribution is made in the examples (i.e. no curves of ideal distribution are drawn, no transformations are made).

Although the eight steps are intended as consequent, in order to demonstrate as many functions as possible, the examples are independent, i.e. outputs from one step are not transferred to another one - you can select another compound and a different approach at each step.

Show introduction to R source code examples

References

Jarkovský J., Dušek L., Klánová J., Hůlek R., Šebková K., Borůvková J., Kalina J., Gregor J., Bednářová Z., Novák R., Šalko M., Hřebíček J., Holoubek I. Multi-matrix online data browser for environmental analysis and assessment [online]. Masaryk University, 2014. Version 1.0. Available from WWW: www.genasis.cz. Version 3.10. March 2014 [2014]