Spatial distribution and reduction of PCDD/PCDF Toxic Equivalents along three shallow lowland reservoirs

Reservoirs situated along a river continuum are ecosystems where rates of transfer of suspended matter and associated micropollutants are reduced due to sedimentation, accumulation, and biological and physical transformation processes. Among the micropollutants, PCDDs and PCDFs are substances that are highly toxic and carcinogenic for humans and animals. They are emitted and dispersed in the environment throughout the whole catchment area and may accumulate in aquatic and terrestrial food chains, creating a risk for human health. A wealth of data exists indicating the increase in the concentrations of pollutants along a river continuum. A comparative analysis of total, individual, and TEQ PCDD/PCDF concentrations in large lowland, shallow reservoirs located in different catchments (“I”—industrial/urban/ agricultural, “U”—urban/agricultural, and “A”—agricultural/ rural) showed decreases of the TEQ concentrations in bottom sediments along a gradient from the middle sections to the dam walls. Moreover, penta-, hexa-, and heptachlorinated CDD/CDF congeners were reduced from 28.8 up to 93.6 % in all three types of reservoirs. A further analysis of water samples from the inlets and outlets of the “A” reservoir confirmed this tendency.The authors wish to express their sincere appreciation to Prof. Konrad Rydzyński from the Nofer Institute of Occupational Medicine in Lodz, Prof. Richard Robarts from the UNEP Global Environment Monitoring System (GEMS)/Water Programme, Prof. Paul DuBowy from the U.S. Army Corps of Engineers, and Prof. David Harper from the Department of Biology, the University of Leicester for their constructive comments on an earlier version of this paper. The authors also wish to acknowledge the research team of the Nofer Institute of Occupational Medicine in Lodz: Dr Danuta Ligocka and Dr Wiktor Wesołowski for their assistance during the laboratory processes. The research was supported by the following projects of the Polish Ministry of Science and Higher Education: – N N305 365738 “Analysis of point sources pollution of nutrients, dioxins and dioxin-like compounds in the Pilica River catchment and draw up of reclamation methods”; – 2PO4 G08830 “Accumulation of dioxins and dioxin-like pollutants in the food chain of the Sulejowski and Włocławski Reservoirs: chemometric analysis and toxicological estimation”

Issues of biological and agricultural treatment of municipal sewage sludge

Increase of sewage sludge production in Poland requires undertaking specific methods for their utilization and disposal. The reason is that sewage sludge, in addition to being rich in organic matter, and biogenic compounds such as nitrogen and phosphorus, which are beneficial from an agricultural point of view, also contain heavy metals, toxic organic pollutants such as persistent organic pollutants and polycyclic aromatic hydrocarbons, inorganic compounds such as silicates and clay, and pathogenic bacteria and other microbial contaminants. This implies problems with further use of such polluted sludge as fertilizer in agriculture. The aim of this paper is to analyze the possibilities and limitations of natural management of sewage sludge, taking into account their effects on the restoration and conservation of organic matter in the soil and the yielding of plants. In addition, the main methods of treatment of polluted sludge before introducing it into the environment are considered