Volatile substances and gases resulting e.g. from degradation processes of chemicals in soils emit into the atmosphere and no chemical mass balance is complete without considering this path. Closed soil chambers allow the evaluation of this transfer to the atmosphere. This study deals with the influence of soil chambers with a glass plate cover on physical soil conditions in the chambers and the possibility to simulate the exterior conditions within the chambers. The water content immediately at the soil surface is an important factor for the microbial activity and the transfer of gaseous compounds to the atmosphere as well. It is monitored by specially designed water content sensors in 1 cm depth in the chamber and as control outside. Funnels with a cross section equal to the soil surface area of the chamber collect the rain water and channel it into the soil chamber. This results in soil water content in the chambers very similar to that outside. For the purpose of analysing ¹⁴CO₂ and volatile ¹⁴C-compounds, air is permanently pumped through the chamber. In order to simulate natural conditions, the wind speed is measured 1 cm above the soil surface outside the chambers. A control circuit adjusts the air flow through the chamber to a value corresponding to the wind speed outside. Temperature measurements in 1 cm depth verify that there is no significant difference between the soil chamber and the control outside.

The distribution of nonylphenol ethoxylates (NPEOn) and their derivatives of nonylphenol (NP) and nonylphenoxy ethoxy acetic acids (NPEnC) in the sediments of a relatively closed freshwater reservoir was investigated using sediment layers sliced from undisturbed sediment cores collected with a gravity core sampler at three sampling sites (St. 1, St. 2 and St. 3) along the water flow direction. The relationships between the bound content of these compounds and the sediment organic matter as well as the likely transformation pathways were evaluated. The total content of NPEOn (n = 1-15) fell in 84.6-336.5, 59.9-135.5 and 77.0-623.4 μg/kg-dry for all sliced layers at St.1, St.2 and St.3, respectively, with the content of individual NPEOn species showing a general decreasing trend with the attached molar number of the ethoxy (EO) chain. Compared to each detected NPEOn species, the bound content of NP was much higher, falling in 73.2-248.4, 79.9-358.2 and 25.5-1,988.4 μg/kg-dry at St. 1, St. 2 and St. 3, respectively. A general increasing trend of the NP content along the water flow direction of the reservoir was revealed. NPEnC (n = 1-10) varied in 1.93-4.12, 2.85-9.84 and 1.05-19.1 μg/kg-dry for sediment at the respective site of St. 1, St. 2 and St. 3, with the averaged values at these sites (2.91, 4.71 and 6.72 μg/kg-dry) showing an increasing trend from the upstream to the downstream. For NPEnC, a parametric trend of increases in the content of NPE₁C, NPE₂C and NPE₃C with the bound sediment organic matter (9.06-11.8%) seemed to be existent. Furthermore, the computed magnitudes of NPEO₁-₂/NPEO₁-₁₅, NP/NPEO₁-₁₅ and NPEC₁-₁₀/NPEO₁-₁₅ suggested that non-oxidative hydrolytic transformation was probably prevailing within the sedimented mud phase of the reservoir, with the oxidative hydrolytic transformation pathway being less involved.