Spatial structures of heavy metals and nitrogen accumulation in moss specimens sampled between 1990 and 2015 throughout Germany

Abstract

Background: The collection of atmospheric deposition by technical samplers and validated deposition modelling using chemical transport models is spatially complemented by using mosses as bioindicator: since 1990, the European moss survey has been providing data on element concentrations in moss every 5 years at up to 7300 sampling sites. In the moss specimens, heavy metals (since 1990), nitrogen (since 2005) and persistent organic pollutants (since 2010) were determined. Germany participated in all surveys with the exception of that in 2010. In this study, the spatial structures of element concentrations in moss collected in Germany between 1990 and 2015 were comparatively investigated by using Moran's I statistics and Variogram analysis and mapped by use of Kriging interpolation. This is the precondition to spatially join the moss survey data with data collected at other locations within different environmental networks and to validate spatial patterns of atmospheric deposition as derived by technical sampling and modelling. Results: The calculated maps reveal a clear and statistically significant decrease of most heavy metals, but not of nitrogen, in moss. Due to decreasing element concentrations and the unchanged application of the element concentration classification for the mapping, the heavy metal maps for the survey 2015 do no longer depict much spatial variation. Conclusions: Therefore, in an upcoming study, this analysis needs to be complemented for the heavy metals by calculating maps that depict the spatial structure of survey-specific percentile statistics

Correlating elements content in mosses collected in 2015 across Germany with spatially associated characteristics of sampling sites and their surroundings

“…Regarding the moss monitoring data, the limits of quantification for the elements determined, as well as the results of the quality control with the moss reference materials M2 and M3 [53], are published in Schröder & Nickel [43]. With the exception of Cr (recovery rate RR = 14%, M3), the element concentrations for M2 and M3 measured in this study did not differ significantly from the respective reference values (RR < 10%), meaning that the recovery rates were in most cases above 90%.…”

“…For N (LE; 2013-2015) and Hg (EMEP; 2013-2015) the calculated deposition in moss monitoring has a mean variable significance, for Cd (EMEP; 2013-2015) a minor significance and for Pb no significance. One reason for the declining explanatory power of deposition at Cd and Pb can be seen in the decrease in atmospheric deposition between 1990 and 2015 [43] and the associated increase in the relative importance of other predictors (surrounding land use, population density). The median of the Cd deposition calculated with the EMEP/MSC-E model decreased from 41.29 to 26.06 µg/m 2 a and for Pb from 1660.33 to 1052.52 µg/m 2 a in the period 2005-2015.…”

“…For As, Cd, Ni, Pb and N, there is good evidence that atmospheric deposition is one of the main factors for the accumulation of substances in mosses [12,26,40]. The level of these correlations varies from element to element depending on the reference areas studied, such as participating states or ecological spatial units [41][42][43][44][45][46][47][48]. For the variance not explained by simple bivariate regression (deposition, accumulation of substances in mosses), further significant predictors could be identified and should be regarded: The spatial density of various land-use classes around the moss sampling sites (agricultural, forestry, urban-industrial, respective areal percentage), the distance and height of adjacent tree stands, the distance to the sea as an indicator of the sea spray effect, the population density, the altitude above sea level as well as the precipitation amount [11,23,24,27,31,52].…”

Determination and Statistical Analysis of Atmospheric Deposition of Heavy Metals in Kosovo. A Moss Survey

“…Collectors have to be built, transported and maintained. This makes it complicated to be operated and expensive in comparison to some naturally grounded methods, such as moss survey (Schröder and Nickel 2019). Mosses grow naturally and it is easier to cover more area with higher density of sampling points with less cost (Harmens et al 2010).…”

Long-term simulation of lead concentrations in agricultural soils in relation to human adverse health effects

“…All these regulatory activities have resulted in reduced Pb immissions into the environment and reduced Pb burden in environmental media. From 1990 to 2015, declining background deposition of Pb could be demonstrated by Pb-monitoring in earthworms (LUBW 2006) and in moss species (Schröder and Nickel 2019). Human biomonitoring reference values for Pb in blood of children in Germany declined from 60 µg/L in 1992 to 50 µg /L in 2003, and finally, 36.3 µg/L in 2009 (Umweltbundesamt 1998(Umweltbundesamt , 2005(Umweltbundesamt ,2009.…”