Kurt Friese

The use of bioindicators for monitoring the heavy-metal status of the environment

Biomonitoring is a method of observing the impact of external factors on ecosystems and their development over a long period, or of ascertaining differences between one location and another. A monitor suitable for the subject of the investigation must be chosen, and the comparability of the element concentrations thus determined (both within the investigation and with other studies) must be ensured by adhering to precise sampling guidelines. In addition to the small amount of equipment required, the advantages of biomonitoring lie in the ecosystem approach that permits conclusions going beyond the biomonitor itself. Attention has to be given to the factors that may affect element concentrations and which can lead to incorrect statements if ignored.

Variations of DOM Quality in Inflows of a Drinking Water Reservoir: Linking of van Krevelen Diagrams with EEMF Spectra by Rank Correlation

Elevated concentrations of dissolved organic matter (DOM) such as humic substances in raw water pose significant challenges during the processing of the commercial drinking water supplies. This is a relevant issue in Saxony, Central East Germany, and many other regions worldwide, where drinking water is produced from raw waters with noticeable presence of chromophoric DOM (CDOM), which is assumed to originate from forested watersheds in spring regions of the catchment area. For improved comprehension of DOM molecular composition, the seasonal and spatial variations of humic-like fluorescence and elemental formulas in the catchment area of the Muldenberg reservoir were recorded by excitation emission matrix fluorescence (EEMF) and ultrahigh-resolution mass spectrometry (FT-ICR-MS). The Spearman rank correlation was applied to link the EEMF intensities with exact molecular formulas and their corresponding relative mass peak abundances. Thereby, humic-like fluorescence could be allocated to the pool of oxygen-rich and relatively unsaturated components with stoichiometries similar to those of tannic acids, which are suspected to have a comparatively high disinfection byproduct formation potential associated with the chlorination of raw water. Analogous relationships were established for UV absorption at 254 nm (UV(254)) and dissolved organic carbon (DOC) and compared to the EEMF correlation.

The use of Fontinalis antipyretica L. ex Hedw. as a bioindicator for heavy metals. 2. Heavy metal accumulation and physiological reaction of Fontinalis antipyretica L. ex Hedw. in active biomonitoring in the River Elbe

Abstract The aquatic moss Fontinalis antipyretica was studied for its ability to accumulate heavy metals. In an exposure test in the River Elbe it was possible to detect an accumulation of heavy metals at the measuring sites of the water monitoring network of the state of Saxonu-Anhalt (Germany). A correlation between these results and the degrees of heavy-metal pollution in the water was only established for Zn and Cd. As a physiological parameter the induction of thiol-containing peptides such as phytochelatins and glutathione under these conditions was investigated. A positive correlation was found between phytochelatin levels and Cd levels in the moss samples. The suitability of this biochemical response to stress as a biomarker for heavy-metal pollution at field locations is discussed.

Biogeochemistry of Iron and Sulfur in Sediments of an Acidic Mining Lake in Lusatia, Germany

Chemical, microbiological and stable isotope analyses of sediments from an acidic mining lake were used to evaluate whether biogeochemical processes, such as iron and sulfate reduction, are extant, because such processes can potentially generate alkalinity. Sediment cores were sliced in cm intervals to achieve a high resolution for spatial distribution of organic and inorganic components. Iron, sulfur, carbon, nitrogen and phosphorus as well as the most probable number (MPN) of iron reducing bacteria, the amount of lipid phosphate and the stable isotope compositions of various sedimentary sulfur compounds were measured. Accumulation of degradable organic material, reduced mass fractions of iron, enhanced concentrations of lipid phosphate, high concentrations of DOC and ferrous iron in the pore water and a drastic change of sulfur isotope ratios in the upper 3 cm of the sediment all indicated a highly reactive zone of biogeochemical transformations. The data provide clear evidence for iron and sulfate reducing processes in the sediments that result in an increase of pH with depth.

First results on the water chemistry, algae and trophic status of an Andean acidic lake system of volcanic origin in Patagonia (Lake Caviahue)

The acidic caldera lake Caviahue (Patagonia, Argentina) and its main tributaries were studied on two dates during September 1998. The main results are: The acidity of the Lake Caviahue (pH: 2.56, acidity: >5 mmol H+ l−1) is controlled by the extremely acidic Upper Rio Agrio (pH: 1.78, acidity: >20 mmol H+ l−1). The high sulphate contents of both the river and the lake can be attributed to sulphuric acid generated by the uptake of sulphurous gases in the crater lake of Copahue Volcano at approximately 2800 m a.s.l. The high concentrations of both Fe and trace metals (e.g. Cr, Ni, Zn) in Lake Caviahue originate from sulphur–acid interactions with the predominantly volcanic geology of the catchment area. The P-rich andesitic geology influences both the Upper and Lower Rio Agrio and Lake Caviahue. Both were found to have high phosphorus concentrations (300–500 μg P l−1) indicative of a high potential for eutrophication. The plankton community consisted of bacterioplankton, phytoplankton and rotifers. The phytoplankton was dominated by one green alga, Keratococcus raphidioides (>90% of total abundance) followed by a green sphaerical and Chlamydomonas sp. The total phytoplankton density was about 15 000 cells ml−1 in the upper 10 m of the water column. Rotifers were represented by one bdelloid species and their abundance was highly variable (360–4040 ind l−1) in the water columm. In the Upper and Lower Rio Agrio, the epilithic community was dominated by one chloroccocal species and two species of Ulothricales. According to trophic categories based on phytoplankton density and TP concentration, Lake Caviahue can be classified as mesotrophic/eutrophic. However, chlorophyll a concentrations observed were not in agreement with this state.

Geostatistical Analysis of Surface Sediments in an Acidic Mining Lake

An exact morphometric description of Mining Lake 111, Brandenburg, Germany, was obtained after a new survey in 1996 by the staff of the water research department. Volume and surface area of ML111 were calculated based on values of this survey. An actual bathymetric map was created from the datapool which was the basis for the selection of sampling sites where we obtained sediment cores to describe the geochemistry of the lake sediments. Principal Component Analysis (PCA) was carried out to examine patterns and similarities between concentrations of different heavy metals. The patterns are different for the three basins within the lake. The spatial distributions of 12 elements in the sediment surface were estimated with a geostatistical procedure (Ordinary Kriging) as well as with a conventional interpolation method. The structure found with PCA was confirmed by the plots from spatial interpolation. Due to the complexity of the lake morphometry and bathymetry 66 sediment cores taken at 47 sampling sites were not sufficient to reduce the spatial variance distributions to acceptable values.

Retrospective analysis of heavy metal concentrations at selected locations in the Federal Republic of Germany using moss material from a herbarium

Abstract In this study, herbarium moss samples taken from selected locations and in different years between 1845 and 1974 were compared with samples from similar locations taken in the context of the German moss monitoring programme of 1991. Samples have been analyzed for the heavy metals arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), vanadium (V) and zinc (Zn). In the herbarium material, the lowest concentrations were found in the early period between 1845 and 1901; the levels rose over the course of time. In general, the element concentrations of the moss samples taken in 1991 are lower than those of the mosses from the herbarium. However, the reverse is true of the elements V and Ni. The differences in concentrations found between the herbarium material and the 1991 moss monitoring samples document both the effects of air pollution resulting from progressive industrialization in the earlier periods and the reduction of heavy metal emissions due to improved methods of preventing air pollution at the present time. Moreover, the results for V and Ni can be interpreted as showing a change in the use of primary sources of energy.

Chemical Characteristics of Water and Sediment in Acid Mining Lakes of the Lusatian Lignite District

Hard and brown coal mining has a long tradition in central and eastern Europe and covers large areas of mining in Germany, Poland and the Czech Republic (Geller et al., this Vol.). In Germany there are three main districts of lignite surface mining: the Rheinish district near Cologne, the mid-German district around Leipzig and the Lusatian district around Cottbus in the most eastern part of Germany. Surface mining of lignite (brown coal) results in several environmental problems, for example important disturbances of the natural water balance, mass transfer of billions of tons of soil and devastation of nature. Among these, water acidification is an already well-known effect. Sulphide minerals, such as pyrite and marcasite, are commonly associated with coal and most metal ores. Weathering and oxidation of these minerals take place in the host rocks and substrates of the lignite horizons when they are exposed to air. The release of the oxidation products, mainly acidity, iron and sulphate, is known as acid mine drainage (AMD) and has been the subject of intense research for decades (e. g. Singer and Stumm 1970; Lowsen 1982; Nordstrom 1982; van Berk 1987; Morrison et al. 1990; Blowes et al. 1991, Hedin et al. 1994; Wisotzky 1994).

Reservoirs as sentinels of catchments: the Rappbode Reservoir Observatory (Harz Mountains, Germany)

Reservoirs can be viewed as sentinels of their catchments and a detailed monitoring of reservoir systems informs about biogeochemical and hydrological processes at the catchment scale. We developed a comprehensive online monitoring system at Rappbode reservoir, the largest drinking water reservoir in Germany, and its inflows. The Rappbode Reservoir Observatory comprises of a set of online-sensors for the measurement of physical, chemical, and biological variables and is complemented by a biweekly limnological sampling schedule. Measurement stations are deployed at the four major inflows into the system, at the outlets of all pre-reservoirs, as well as in the main reservoir. The newly installed monitoring system serves both scientific monitoring and process studies, as well as reservoir management. Particular emphasis is paid to the monitoring of short-term dynamics and many variables are measured at high temporal resolution. As an example, we quantitatively documented a flood event which mobilised high loads of dissolved organic carbon and changed the characteristics of the receiving reservoir from eutrophic to dystrophic within a few days. This event could have been completely missed by conventional biweekly sampling programs, but is relevant for biogeochemical fluxes at the catchment scale. We also show that the high frequency data provide a deeper insight into ecosystem dynamics and lake metabolism. The Rappbode Reservoir Observatory; moreover, offers a unique study site to apply, validate, and develop state of the art lake models to improve their predictive capabilities.

Phosphorus Retention Mechanisms in the Sediment of an Eutrophic Mining Lake

A small, highly eutrophic mining lake (Golpa IV) in eastern Germany with a continuous input of nutrients and metals was used to study the mechanisms of phosphorus (P) fixation in the sediment. The sediment (0-15 cm) is characterised by high contents of iron (96 mg g-1 DW), aluminium (37.3 mg g-1 DW) and sulphur (54.3 mg g-1 DW) and an extreme accumulation of some trace metals. Despite oxygen free conditions in the hypolimnion and intensive sulphate reduction in the sediment, high P retention rates could be calculated from dated sediment cores (1986-1995: 11 g P m-2 a-1). The lake has shown a rapid response to reduction of P loading.In some sediment layers unusually high total sediment P concentrations with more than 24 mg P g-1 DW were observed. More than 80% of total sediment P was bound in the BD-SRP and NaOH-SRP fractions (extraction scheme according to Psenner et al., 1984) which indicates that a substantial portion of deposited P is immobilised in an Fe or Al bound form. This corresponds well with the presence of oxidised Fe species at all sediment depths. Furthermore thermodynamic calculations indicate that vivianite precipitation is favourable in deeper anoxic sediment layers. The inventory or input of Fe or Al seems to be more important for the permanent P immobilisation in the sediment of the investigated mining lake than redox forced mobilisation processes (e.g. iron or sulphate reduction).