Influence Of Sewage Sludge Application Research Articles

Structural and Predicted Functional Diversities of Bacterial Microbiome in Response to Sewage Sludge Amendment in Coastal Mudflat Soil.

Simple SummaryImproving microbial community and functional diversity is essential for the fertility activation and development of coastal mudflat soils, an important reserve resource for sustainable agricultural development. Although sewage sludge has been proven to be an effective agricultural practice to alleviate saline sodic stress and nutrient deficiency and thereby enable coastal mudflat reclamation, knowledge regarding the structural and functional diversities of bacterial microbiome in response to sewage sludge application remains unclear. In this study, we simultaneously investigated the effects of sewage sludge amendment on physicochemical characteristics, composition, diversity, and predicted function of bacterial community in coastal mudflat soil. Results revealed that both structural and functional diversities of bacterial microbiome were significantly improved due to microhabitat modification (i.e., mitigated saline–alkali and nutrient deficiency conditions) induced by sewage sludge amendment compared to untreated soil. Additionally, bacterial groups involved in cycling processes of carbon and nitrogen were significantly enriched in sewage sludge-amended mudflat soils. The current study enhanced our understanding of mechanisms underlying microbial community and functional diversities promoted by sewage sludge amendments.The study investigated the influence of sewage sludge application at rates of 0 (CK), 30 (ST), 75 (MT), and 150 (HT) t ha−1 to mudflats on bacterial community diversity and predicted functions using amplicon-based sequencing. Soils under sewage sludge treatments, especially the HT treatment, exhibited lower pH, salinity and higher nutrient contents (C, N, and P). Moreover, restructured bacterial communities with significantly higher diversities and distinct core and unique microbiomes were observed in all sewage sludge-amended soils as compared to the control. Specifically, core bacterial families, such as Hyphomicrobiaceae, Cytophagaceae, Pirellulaceae Microbacteriaceae, and Phyllobacteriaceae, were significantly enriched in sewage sludge-amended soils. In addition, sewage sludge amendment significantly improved predicted functional diversities of core microbiomes, with significantly higher accumulative relative abundances of functions related to carbon and nitrogen cycling processes compared to the unamended treatment. Correlation analyses showed that modified soil physicochemical properties were conducive for the improvement of diversities of bacterial communities and predicted functionalities. These outcomes demonstrated that sewage sludge amendment not only alleviated saline–sodic and nutrient deficiency conditions, but also restructured bacterial communities with higher diversities and versatile functions, which may be particularly important for the fertility formation and development of mudflat soils.

Influence of sewage sludge application on soil properties, carrot growth and heavy metal uptake

ABSTRACT A pot experiment with carrot (Daucus Carota L.) was conducted aiming to investigate some soil properties, growth and heavy metal uptake by carrot with the application of sewage sludge. The treatments used were as T1 Control (Soil only), T2 (Soil + NPK), T3 (Soil 50% and sewage sludge 50%), T4 (Soil 60% + sewage sludge 40%), T5 (Soil 70% + sewage sludge 30%) and T6 (100% Sewage sludge). The results showed that sewage sludge application significantly influenced soil pH, organic matter (OM), electrical conductivity (EC), exchangeable potassium (K) and available phosphorus (P). Heavy metals like lead (Pb), cadmium (Cd), nickel (Ni) and chromium (Cr) content in soil and plant were increased due to the application of sewage sludge. Heavy metal content in soils for different sludge treatments was lower and that in carrot samples was higher than the WHO/FAO permissible limit. The carrot was recognized by a translocation factor <1.0 for all of the heavy metals except Cd. Plant heavy metal concentrations were positively correlated with the soil organic matter content and negatively correlated with soil pH. The growth of carrot was influenced positively with sewage sludge application. Maximum fresh weight (66.3 g plant-1) was recorded in T5 treatment, and maximum dry weight (5.61 g plant-1) was in T3 treatment. The soil application of sludge improves soil fertility and enhances the better yield of carrot. Moreover, sewage sludge could be co-recycled to take simultaneously the best profit and minimize environmental pollution.

Sewage Sludge Influences Nitrogen Uptake, Translocation, and Use Efficiency in Sunflower

A better understanding of crop and soil response to biosolids is necessary for optimizing their use as soil amendments. The present study examined the influence of sewage sludge application on N accumulation, partitioning, translocation, and N use in sunflower and on soil properties compared with mineral fertilizers. Treatments included the application of sewage sludge (9, 18, and 36 Mg dry weight ha−1 year−1), an inorganic fertilizer (138 kg N plus 55 kg P2O5 ha−1 year−1), and a non-amended control. Sewage sludge increased early crop growth rate and N uptake at levels similar to or even greater than those obtained with the inorganic fertilizer. Nitrogen translocation was correlated with nitrogen translocation efficiency (r = 0.66*); both parameters appeared to be associated with source and sink attributes. Nitrogen use efficiency and nitrogen uptake efficiency were decreased with increasing rates of sewage sludge following a quadratic response curve. The estimated nitrogen use efficiency of sewage sludge-added N was greater than that of the inorganic fertilizer when sewage sludge was applied at agronomically realistic rates (< 26 Mg ha−1 in the first year or < 18 Mg ha−1 in the second year). Sewage sludge application increased soil organic matter and Olsen P compared with the control. Soil electrical conductivity in sewage sludge treatments remained at acceptable levels and soil concentrations of DTPA-extractable trace elements were similar to those of the control or the inorganic fertilizer. In the light of these findings, treated municipal sewage sludge may be used in sunflower intended for biodiesel production replacing mineral fertilizers serving as alternative sewage sludge disposal method.

Gene expression, DNA damage and other stress markers in Sinapis alba L. exposed to heavy metals with special reference to sewage sludge application on contaminated sites

Bioindicators are promising tools used to detect the long-term effects of selected biosolids on plants development and should be implemented before large-scale supplementation of sewage sludge into the soil. The presented study shows the impact of sewage sludge application on metal-sensitive toxicity biological parameters (biomarkers) in Sinapis alba including: germination, root length, the activity of guaiacol peroxidase, the chlorophyll content, the level of DNA damage and the expression level of Ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL) and metallothionein (mt). We evaluated data from selected biomarkers in order to broaden our understanding of plants defense mechanisms against heavy metal contamination and the application of sewage sludge into soils. Overall, in contaminated soil after supplementation with both municipal sewage sludges, an increase in toxicity was noticed in DNA damage, mt and rbcl expression and total chlorophyll content. The supplementation of both soils with municipal sewage sludge caused a two-time induction in the mt expression. Moreover, clean soil supplemented with sewage sludge caused an increase in DNA damage shown as the tail moment from approximately 12 μm on control to 40 μm after supplementation. Even if those biosolids increased the initial germination, roots length, and biomass in comparison to the unamended soil, the toxicity was evidenced with other stress markers. Results showed, that in order to accurately assess the influence of sewage sludge application on plants the use of several specific biomarkers is required for safe land restoration. The conducted study also confirmed, both under biochemical and genotoxic tests, that iron enrichment for biosolids or contaminated soil can significantly reduce the bioavailability and toxicity of other metals.

Effect of Sewage Sludge Amended Soil on Maize Crop. II. Influence on metal accumulation

The aim of the present study was to evaluate the influence of sewage sludge application on metal accumulation (Cu, Mn, Zn, Cd, Ni, Pb) at maize (Zea Mays L.). It was applied different doses varying from 0-600 kg/ha of sewage sludge associated with mineral fertilization. The results indicated that copper and manganese contents increase with fertilization and rates equivalent to 200 kg N/ha resulted in statistically significant copper content in the maize leaves. The highest accumulation of manganese in the leaves was recorded at the sludge rate equivalent to 300 kg N/ha, meanwhile in the maize kernels after the increasing sludge rate, the manganese content recorded a decreasing tendency. The zinc content in the maize leaves significantly increased with the increasing rate of sludge, starting with a rate equivalent to 200 kg N/ha, sewage sludge application being a promoter of zinc accumulation but without becoming excessive. As concerns the zinc content in the maize kernels, sewage sludge rates higher than 300 kg N/ha resulted in statistically assured increases. The cadmium level in the maize leaves increased directly proportional with the rate applied and the values were statistically assured at rates higher than 200 kg N/ha. The cadmium content in the maize kernels was not affected by the treatments applied, as the very low values obtained were below the detection limit of the analytical method. The lead content in the maize leaves increased under the influence of sludge fertilization, but the accumulation was generally low, all values in leaves being under 10 mg/kg and in kernels under 1 mg/kg Pb.

Application of sewage sludge improves growth, photosynthesis and antioxidant activities of nodulated alfalfa plants under drought conditions

We have examined the influence of sewage sludge application on the capacity for acclimation to drought of N 2-fixing alfalfa plants ( Medicago sativa L. cv. Aragón). Plants were grown in pots with a mixture of perlite and vermiculite (2:1, v/v) and sludge, which was incorporated into substrate at rate of 10% (w/w). Pots without sludge but with inoculated plants were used as control treatment for comparison. Two levels of irrigation were imposed: (1) well-watered and (2) drought stress during three cycles of moisture stress and recovery. Sludge application improved net photosynthesis resulting in higher plant growth and photosynthetic products (soluble sugars) required for nodule metabolism. Drought did not alter nodule soluble proteins or leghemoglobin concentration but nodule dry mass was strongly decreased. Under drought, nodules of sludge-treated plants had higher N-compounds as proline, antioxidant metabolites as ascorbate and some antioxidant enzyme activities as catalase than untreated plants. All these changes might have contributed to protect nodules from oxidative stress as indicated by low products of lipid peroxidation. This study provides evidence for a beneficial effect of sewage sludge application for nodulated alfalfa plants subjected to cyclic drought.

The seven year itch—progress in research on endocrine disruption in aquatic invertebrates since 1999

Since the issue of endocrine disrupting chemicals (EDCs) emerged, research efforts were mainly devoted to (1) vertebrate systems, and (2) estrogenic substances. In ecotoxicology, terrestrial wildlife populations (e.g. puma) were investigated, while in the aquatic environment fish and amphibians were in focus. That invertebrates, which constitute the major part of our animal biodiversity, were largely ignored in the equation (except maybe for the effects of tributyltin on marine molluscs), encouraged scientists on both sides of the ocean to bundle their efforts and organise a workshop to explore the status quo on invertebrate endocrinology. Finally, the workshop ENDOCRINE DISRUPTION IN INVERTEBRATES: ENDOCRINOLOGY, TESTING AND ASSESSMENT (EDIETA) was held in The Netherlands in 1998. This highly successful workshop culminated in the SETAC publication carrying the same title as the workshop (deFur et al. 1999). Since its publication this book has become a reference work for researchers, lecturers, students and regulators that were involved in the various aspects of invertebrate endocrinology, from basic research to the regulatory implications of endocrine disruptor testing. Moreover, since the book provided many suggestions for improvement and indicated gaps in our knowledge, it also served as a starting point for further research. It was our impression that in the past 7 years a great effort has been undertaken to fill these data gaps and to improve our understanding of invertebrate endocrinology. While this knowledge has been brought into use for aquatic invertebrates, relatively little progress has been made in understanding endocrine disruption in terrestrial invertebrates (although a springtail reproduction test has been initiated at the OECD level). This may be related to issues with terrestrial exposures, which are harder to define than for aquatic invertebrates, which experience an aqueous whole body exposure. For example, the influence of a sewage effluent (including residues of the potent estrogen 17aethinylestradiol) is easily measurable in aquatic ecosystems, while it is hard to measure the influence of sewage sludge application on terrestrial ecosystems. This is due to (1) complicating matrix effects in the chemical analysis, (2) considerable heterogeneity of the soil, (3) the mitigating effect of soil due to its high adsorptive capacity and (4) the lack of established terrestrial bioassays for endocrine disruptors. From the start our focus has been on Endocrine disruption in aquatic invertebrates, a topic on which we organised and chaired a session at the Annual meeting of SETAC-Europe in Lille, France in May 2005. There we started thinking about the compilation of a special issue on this subject. That our initiative succeeded is not only due to the possibility that SETAC gave us to organise the aforementioned session, but also to the editors of Ecotoxicology who gave us the editorial time and space to compile this work. Furthermore, it was particularly encouraging that virtually all authors we L. Weltje (&) Agricultural Center, Ecotoxicology, BASF Aktiengesellschaft, Carl-Bosch-Strasse 64, D-67117 Limburgerhof, Germany e-mail: lennart.weltje@basf.com

Influence of Sewage Sludge Application on Soil Nitrate Distribution in a Clay Soil

Nitrate contamination in the aquatic systems is the primary indicator of poor agricultural management. The influence of sewage sludge application rates (0, 10, 25, 50 and 100 dry Mg/ha) on distribution of nitrate originating from the sewage sludge in soil profiles was investigated. Soil profile monitoring of nitrate was carried out with a Lakeland clay soil in 1997. Irrespectively of the sewage sludge application rates up to 50 dry Mg/ha, the concentration of <TEX>$NO_3$</TEX>-N at the 120 cm depth was below 10 mg/kg and the difference due to the amount of sewage sludge application was negligible at this depth. There was virtually no <TEX>$NO_3$</TEX>-N below 120 cm depth and this was confirmed by a deep sampling up to 300 cm depth. Most of the nitrate remained in the surface 60 cm of the soil. Below 120 cm depth nitrate concentration was very low because of the denitrification even at high sewage sludge rate of 100 dry Mg/ha. The <TEX>$NO_3$</TEX>-N concentrations in the soil fluctuated over the growing season due to plant uptake and denitrification. The risk of groundwater contamination by nitrate from sewage sludge application up to high rate of 100 dry Mg/ha was very low in a wheat grown clay soil with high water table ( < 3 m).

Influence of sewage sludge application on physical and chemical properties of Gypsisols

The abundant gypsiferous soils of the semi-arid central Ebro valley are very sensitive to environmental change. Poor land management practices have caused severe degradation of the soils near the city of Zaragoza, leading to loss of productivity and of ecological function and badland formation on the slopes. The use of sewage sludge for land rehabilitation is increasingly being considered as a technical solution to reverse this environmental degradation and to promote the re-establishment of vegetation cover. This paper describes changes in selected properties of a Gypsisol following the addition of sewage sludge. Experiments investigating the influence of a range of application rates were conducted on 60×100 cm plots. The magnitudes of increase in salinity and decrease in pH were found to be dependent on the sludge application rate. Several beneficial changes were observed including increases in organic matter, organic carbon and nitrogen content as well as in soil moisture and porosity. On the other hand, concentrations of major cations and heavy metals also increase after sewage sludge addition, although, their levels are below the standard limits fixed by the European Union. In order to avoid undesirable side-effects—salinity and toxic concentrations of metals—resulting from the application of sewage sludge to gypsiferous soils in semi-arid environments, it is necessary to characterize the sewage sludge and to determine the most suitable doses. This work highlights the potential of using sewage sludge for land reclamation of degraded soils in semi-arid environments. Nevertheless, the complexity of the processes involved requires further research to ensure the safety of sludge application.

Influence of sewage sludge application on soil properties and on the distribution and availability of heavy metal fractions

Abstract The influence of sewage sludge application on some soil properties and on the growth of wheat and corn plants were studied with pot experiments. The distribution of heavy metals among the various soil fractions and their availability to plants were also investigated in relation to soil pH. The results showed that sewage sludge application significantly ifluenced pH, organic matter content, electrical conductivity and available phosphorus. Soil pH increased and tended to hold steady near neutrality while organic matter content, electrical conductivity and available phosphorus (P) increased. For the heavy metals investigated, only total copper (Cu) and zinc (Zn) increased but were below the limits set by the EC. A significant increase was observed in the concentrations of cadmium (Cd), nickel (Ni), Cu, and Zn extracted by DTPA while iron (Fe) and manganese (Mn) were reduced showing a strong relationship to soil pH. For the metals sequentially extracted it was observed that chromium (Cr), Ni, Cu, an...

Influence of sewage sludge application on crop yields and heavy metal availability

Abstract A calcareous soil with a low content of organic matter was treated with aerobic or anaerobic sewage sludge. In the same way, chicken manure was used for comparison. Influences on crop yields and the supply of macronutrients and heavy metals to soil and plant tissues were studied. In the soil amended with the sludges the total N and extractable N and P contents increased, whereas the extractable K level remained nearly constant. Samples which had undergone a period of humification prior to sowing, mineralized part of their organic N and P during this period of time. Through sludge application, the levels of Cu, Zn, and Pb increased, the Fe content decreased while the extractability of Fe, Cu, Mn, Zn, and Pb increased as compared to the control. Sludge application enhanced the maize and barley yields as is the case of chicken manure. Sewage sludges supplied a considerable amount of available N to the plants, whereas the supply.of available K was low. In the barley plants it was observed that the higher the yield, the higher the N and K contents, while in the maize crop this trend was only observed for K. Plants grown on soil amended with sludges absorbed a larger amount of Fe, Cu, and Zn than those grown on the control soil. It was demonstrated that heavy metal absorption by the plants depended on the vegetal species.