Heavy metal-contaminated soil derived from a former uranium mining site in Ronneburg, Germany, was used for sterile mesocosms inoculated with the extremely metal-resistant Streptomyces mirabilis P16B-1 or the sensitive control strain Streptomyces lividans TK24. The production and fate of bacterial hydroxamate siderophores in soil was analyzed, and the presence of ferrioxamines E, B, D, and G was shown. While total ferrioxamine concentrations decreased in water-treated controls after 30 days of incubation, the sustained production by the bacteria was seen. For the individual molecules, alteration between neutral and cationic forms and linearization of hydroxamates was observed for the first time. Mesocosms inoculated with biomass of either strain showed changes of siderophore contents compared with the non-treated control indicating for auto-alteration and consumption, respectively, depending on the vital bacteria present. Heat stability and structural consistency of siderophores obtained from sterile culture filtrate were shown. In addition, low recovery (32 %) from soil was shown, indicating adsorption to soil particles or soil organic matter. Fate and behavior of hydroxamate siderophores in metal-contaminated soils may affect soil properties as well as conditions for its inhabiting (micro)organisms.

Intensive agriculture has resulted in an indiscriminate use of pesticides, which demands in-depth analysis of their impact on indigenous rhizospheric microbial community structure and function. Hence, the objective of the present work was to study the impact of two chemical pesticides (chlorpyrifos and cypermethrin) and one biological pesticide (azadirachtin) at two dosages on the microbial community structure using cultivation-dependent approach and on rhizospheric bacterial communities involved in nitrogen cycle in Vigna radiata rhizosphere through cultivation-independent technique of real-time PCR. Cultivation-dependent study highlighted the adverse effects of both chemical pesticide and biopesticide on rhizospheric bacterial and fungal communities at different plant growth stages. Also, an adverse effect on number of genes and transcripts of nifH (nitrogen fixation); amoA (nitrification); and narG, nirK, and nirS (denitrification) was observed. The results from the present study highlighted two points, firstly that nontarget effects of pesticides are significantly detrimental to soil microflora, and despite being of biological origin, azadirachtin exerted negative impact on rhizospheric microbial community of V. radiata behaving similar to chemical pesticides. Hence, such nontarget effects of chemical pesticide and biopesticide in plants’ rhizosphere, which bring out the larger picture in terms of their ecotoxicological effect, demand a proper risk assessment before application of pesticides as agricultural amendments.

Piscifaunal health depends upon the state and quality of the aquatic environment. Variations in physical condition of fish may therefore be attributed to changes in environmental quality. Based on time series of up to 20 years of biometric data of bream from multiple sampling sites of the German environmental specimen bank (ESB), this study assessed whether changes in biometric parameters are able to indicate long-term alterations in fish health and environmental quality. Evaluated biometric parameters of fish health comprised length and weight of individuals of a defined age class, the condition factor, lipid content and hepatosomatic index (HSI). Although there are negative trends of the HSI, the overall development of health parameters can be interpreted as positive. This seems to suggest that health parameters conclusively mirror the long-term improvement of water quality in the selected rivers. However, the applicability of the condition factor as well as lipid content as indicators for fish health remained subject to restrictions. Altogether, the results from the ESB confirmed the high value of biometric parameters for monitoring of long-term changes in state and quality of aquatic ecosystems.

Adsorption/desorption and desorption hysteresis of methamphetamine (MMA) on carbon nanotubes (CNTs) as well as bioavailability of MMA were studied in simulated gastrointestinal fluids and background fluids. Adsorption of MMA in near-neutral (weak alkaline) intestinal fluid was enhanced, while adsorption of MMA on CNTs in acid gastric fluid was suppressed. Desorption of MMA is divided into fast and slow stages, and fast desorption conducting in the gastric fluid lasted shortly and slow desorption occurred in intestinal fluid; pepsin can enhance the release of MMA in gastrointestinal system. While, the acidic condition in gastric fluid is the main factor which causes the release of MMA. The amount of MMA released from CNTs in different fluids follows the order gastric > background (pH = 2.0) > intestinal (fed) > intestinal (fasted) > background (pH = 7.5). These findings in the simulated gastrointestinal system suggest that the release of MMA from CNTs could be promoted by biomacromolecules (such as pepsin and bile salts in digestive tract); thus, the bioavailability of MMA is enhanced.

Residues of polybrominated diphenyl ethers (PBDEs), including eight PBDE congeners, were investigated in soils and plants from a deca-BDE manufacturing factory located in the Shandong province of China to evaluate and discuss their pollution level and distribution. Total concentrations in topsoil ranged from 17.0 to 146 μg g⁻¹dry weight (dw) with a mean value of 58.7 μg g⁻¹dw. BDE-209 was the dominant congener in soils, accounting for 55.63–99.27 % of the total PBDEs. Concentrations and congener patterns in soils varied among different soil depths. Concentration levels in topsoil are high and the heavy accumulation in deep soil also can be observed, even for some sites, the concentrations in 50–100 cm depth are higher than in topsoil. In plant samples, total PBDE concentrations and the proportion of BDE-209 were high (69.92–99.10 %). The extent of pollution by PBDEs in the deca-BDE production factory was higher than in other regions, and the environmental risk caused by the production of deca-BDE is of concern. This is the first study to report pollution of PBDEs in soils and plants from the vicinity of a deca-BDE manufacturing factory.

The surfaces of natural sediments are ubiquitously coated by biofilms that increase the content of organic matter in sediments. However, it is less understood whether the biofilms act as a sorbent or a barrier of mass transfer from water column to sediment phase. This study focused on the role of biofilms coverage on sediments in the sorption of bisphenol A (BPA), 17α-ethinyl estradiol (EE2), and 4-nonylphenols (4-NP) as model compounds for endocrine-disrupting chemicals (EDCs). The OC-normalized distribution coefficients (kOC) for BPA, EE2 and 4-NP ranged from 10¹.⁸⁷to 10³.⁰⁹ l/kg, the kOCof EE2 was slightly higher (10².²³ l/kg) for sediment after H₂O₂oxidation than before (10¹.⁹³ l/kg). A two-stage model with a fast section and slow section was employed to describe the sorption process (r² > 0.95). The model results showed that the fast sorption section played a main role in the sorption process, while the slow section determined the extent of the reaction (the second-phase partition coefficient (kₚ₂) ranged from 11.7 to 118.9 l/kg). The ratios of the mass transfer rate constant of the two stages for the natural sediment ranged from 6.0 to 7.2, which were somewhat lower than those for soil samples. These results indicated that the biofilm coverage on sediment may act as a barrier in mass transfer from water to sediment and scarcely increased the sorption capacity of sediments.

Photodegradation of methylene blue (MB) was studied on TiO₂in the presence of activated carbon (AC) prepared from the sawdust of a soft wood by physical activation under CO₂flow, by pyrolysis under N₂flow, and by chemical activation with ZnCl₂and H₃PO₄under N₂flow. MB photodegradation was performed under UV and UV-visible irradiation to verify the scaling-up of the present TiO₂-AC binary materials. It was verified that oxygenated surface groups on carbon were intrinsically photoactive, and a synergy effect between both solids has been estimated from the first-order apparent rate constants in the photodegradation of MB. This effect enhances the photoactivity of TiO₂up to a factor of about 9 under visible irradiation, and it was associated to the surface properties of AC.

The toxicity of four zinc oxide nanoparticles (i.e., spheric ZnO-30, spheric ZnO-50, columnar ZnO-90, and hexagon rod-like ZnO-150) to the seed germination of Chinese cabbage (Brassica pekinensis L.) was investigated in this study. The results showed that zinc oxide nanoparticles (nano-ZnOs) did not affect germination rates at concentrations of 1–80 mg/L but significantly inhibited the root and shoot elongation of Chinese cabbage seedlings, with the roots being more sensitive. The inhibition was evident mainly during seed incubation rather than the seed soaking process. Both the production of free hydroxyl groups (·OH) and the Zn bioaccumulation in roots or shoots resulted in toxicity of nano-ZnOs to Chinese cabbage seedlings. The toxicity of nano-ZnOs was affected significantly by their primary particle sizes in the minimum dimensionality, but large columnar ZnO-90 and small spherical ZnO-50 had comparable toxicities. Therefore, both the particle size and morphology affected the toxicity of nano-ZnOs.

Despite the key role of higher plants in aquatic ecosystems as functional and structural elements, sediment-contact tests with macrophytes are still scarce. Moreover, due to large differences in exposure routes for pollutants as well as in life cycles between the diverse taxa of macrophytes, sensitivities to pollutants vary between taxa. Therefore, the development of new test systems with aquatic macrophytes, in general, is favorable. This study proposes a protocol for a sediment-contact test with Oryza sativa and addresses the main question whether the rice plant is a suitable test organism for sediment toxicity testing with higher plants. As a first evaluation step, the variability and sensitivity of the test was investigated using spiked artificial sediments. Thus, according to the protocol, rice was exposed to arsenic-, cadmium-, chromium-, and nickel-spiked sediments. Additionally, it was investigated which classical endpoints for plant bioassays, such as root and shoot elongation, are suitable for this bioassay. As a second evaluation step, the test system was used for assessment of natural sediments. Thereupon, a sensitivity profile of the presented test protocol was analyzed in comparison to other plant-based test systems. Inhibition of root and shoot elongation turned out to be the most sensitive endpoints for single-substance testing in spiked artificial sediments. However, regarding testing of natural sediments, rice shoots responded more sensitive than rice roots. In conclusion, the rice plant clearly showed pollutant-induced effects on growth in sediments, and thus, it is likely a promising test organism to complement sediment-contact tests with higher plants.

China has been confronted with serious water quality deterioration concurrent with rapid socioeconomic progress during the past 40 years. Consequently, knowledge about economic growth and lake water quality dynamics is important to understand eutrophication processes. Objectives were to (i) reconstruct historical nutrient accumulation and the basin economic progress on burial flux (BF); (ii) determine forms and structures of nitrogen (N) and phosphorus (P) in sediment and water using six cores in three of the most severely eutrophic lake areas in China (i.e., Eastern Plain, Yunnan-Guizhou Plain, and Inner Mongolia–Xinjiang regions). Results suggest that BFs of total nitrogen (TN) continued to increase in sediment, whereas total phosphorus (TP) levels were consistent or only slightly increased, except in highly polluted lakes during the past decades. Similar results were observed for concentrations of nutrients in water (i.e., increased N/P). This historical distribution pattern was correlated to long-term fertilization practices of farmers in the watershed (N fertilization exceeds that of P) and was contingent upon pollution control policies (e.g., emphasized P whereas N was ignored). Vertical profiles of BFs indicated that lake nutrient accumulation included three stages in China. Nutrient accumulation started in the 1980s, accelerated from the 1990s, and then declined after 2000. Before the 1980s, nutrients were relatively low and stable, with nutrient inputs being controlled by natural processes. Thereafter, N- and P-bound sediments dramatically increased due to the increasing influence of anthropogenic processes. Nutrients were primarily derived from industries and domestic sewage. After 2000, BFs of nutrients were steady and even decreased, owing to implementation of watershed load reduction policies. The decreasing NaOH-extracted P (Fe/Al–P) and increasing organic phosphorus (OP) indicated that the source of exogenous pollution underwent a shift. Inputs of nutrients were predominantly from agricultural and domestic sewage, whereas industrial pollution has been gradually controlled in most of the watersheds. Historical nutrient dynamics suggest that the economy of China is growing at the expense of its aquatic ecological environments. Therefore, more attention to nutrient export to groundwater resulting from economic development is important for further aquatic ecosystem deterioration and eutrophication in China.