Predicting the Stability of Organic Matter Originating from Different Waste Treatment Procedures.

Recycling organic wastes into farmland faces a double challenge: increasing the carbon storage of soil while mitigating CO emission from soil. Predicting the stability of organic matter (OM) in wastes and treatment products can be helpful in dealing with this contradiction. This work proposed a modeling approach integrating an OM characterization protocol into partial least squares (PLS) regression.

Changes in soil carbon mineralization related to earthworm activity depend on the time since inoculation and their density in soil.

Earthworms play a key role in soil carbon mineralization, but their effect is highly uncertain and suspected to vary as a function of several factors, particularly the earthworm density and time from earthworm inoculation. We conducted a meta-analysis considering these factors based on 42 experiments comparing carbon mineralization in the absence and presence of earthworms at different times. The results reveal an average carbon mineralization increase of 24% (sd 41%) in the presence of earthworms with an initial median earthworm density of 1.

Soil aggregates as biogeochemical reactors: Not a way forward in the research on soil-atmosphere exchange of greenhouse gases.

The goal of this comment is to show that the "aggregate reactor" framework recently proposed in an article published in this journal is severely limited by two kinds of indeterminacy. The first is related to the size of aggregates, which is not defined precisely. The second issue is with the impossibility to replicate boundary conditions that are identical to what chunks of soils would have experienced in their natural state.

Fate of C-acetyl sulfamethoxazole during the activated sludge process.

Compared to antibiotic parent molecule, human metabolites are generally more polar and sometimes not less toxic in wastewater. However, most researches focus on the fate of parent molecule. Therefore, behaviors of human metabolites are little known.

Environmental availability of sulfamethoxazole and its acetylated metabolite added to soils via sludge compost or bovine manure.

The fate of antibiotics and their metabolites in soils after application of organic waste depends on their environmental availability, which depends on the quality and biodegradability of the added exogenous organic matter (EOM). This study aimed at better understanding the fate of sulfamethoxazole (SMX) and N-acetyl-sulfamethoxazole (AcSMX) metabolite added to soils via sludge compost or cow manure application, during a 28-day incubation. Experimental results obtained for mineralized, extractable, and non-extractable fractions as well as EOM mineralization were used to couple SMX and AcSMX dynamics to the EOM evolution using the COP-Soil model.

Emergent Properties of Microbial Activity in Heterogeneous Soil Microenvironments: Different Research Approaches Are Slowly Converging, Yet Major Challenges Remain.

Over the last 60 years, soil microbiologists have accumulated a wealth of experimental data showing that the bulk, macroscopic parameters (e.g., granulometry, pH, soil organic matter, and biomass contents) commonly used to characterize soils provide insufficient information to describe quantitatively the activity of soil microorganisms and some of its outcomes, like the emission of greenhouse gasses.

Microscale Heterogeneity of the Spatial Distribution of Organic Matter Can Promote Bacterial Biodiversity in Soils: Insights From Computer Simulations.

There is still no satisfactory understanding of the factors that enable soil microbial populations to be as highly biodiverse as they are. The present article explores the hypothesis that the heterogeneous distribution of soil organic matter, in addition to the spatial connectivity of the soil moisture, might account for the observed microbial biodiversity in soils. A multi-species, individual-based, pore-scale model is developed and parameterized with data from 3 sp.

Mulch of plant residues at the soil surface impact the leaching and persistence of pesticides: A modelling study from soil columns.

Crop residues left on the soil surface as mulch greatly influence the fate of pesticides in conservation agricultural practices because most of the applied pesticide is intercepted by mulch before passing to the soil. Modelling of pesticide losses from wash-off and leaching will greatly improve our understanding of the environmental consequences of pesticides in these systems. The PASTIS model, which simulates water transfer, mulch decomposition, and pesticide dynamics, was adapted in this new version to model the interactions between pesticides and mulch in order to simulate the impact of mulch on pesticide dynamic.

Impact of sludge treatments on the extractability and fate of acetyl sulfamethoxazole residues in amended soils.

Sludge recycled in agriculture may bring antibiotics into cropped soils. The nature, total amount, and availability of the antibiotics in soil partly depend on the sludge treatments. Our paper compares the fate of N-acetyl sulfamethoxazole (AC-SMX) residues between soils incubated with the same sludge but submitted to different processes before being added in soil.

In situ long-term modeling of phenanthrene dynamics in an aged contaminated soil using the VSOIL platform.

Management and remediation actions of polycyclic aromatic hydrocarbons (PAH) contaminated sites require an accurate knowledge of the dynamics of these chemicals in situ under real conditions. Here we developed, under the Virtual Soil Platform, a global model for PAH that describes the principal physical and biological processes controlling the dynamics of PAH in soil under real climatic conditions. The model was applied first to simulate the observed dynamics of phenanthrene in situ field experimental plots of industrial contaminated soil.

Modelling the fate of PAH added with composts in amended soil according to the origin of the exogenous organic matter.

A new model that was able to simulate the behaviours of polycyclic aromatic hydrocarbons (PAH) during composting and after the addition of the composts to agricultural soil is presented here. This model associates modules that describe the physical, biological and biochemical processes involved in PAH dynamics in soils, along with a module describing the compost degradation resulting in PAH release. The model was calibrated from laboratory incubations using three C-PAHs, phenanthrene, fluoranthene and benzo(a)pyrene, and three different composts consisting of two mature and one non-mature composts.

Using a Bayesian approach to improve and calibrate a dynamic model of polycyclic aromatic hydrocarbons degradation in an industrial contaminated soil.

A novel kinetics model that describes the dynamics of polycyclic aromatic hydrocarbons (PAHs) in contaminated soils is presented. The model includes two typical biodegradation pathways: the co-metabolic pathway using pseudo first order kinetics and the specific biodegradation pathway modeled using Monod kinetics. The sorption of PAHs to the solid soil occurs through bi-phasic fist order kinetics, and two types of non-extractible bounded residues are considered: the biogenic and the physically sequestrated into soil matrix.

Impact of liming and drying municipal sewage sludge on the amount and availability of (14)C-acetyl sulfamethoxazole and (14)C-acetaminophen residues.

Acetyl Sulfamethoxazole (AC-SMX) and acetaminophen (ACM) can be found in municipal sewage sludge, and their content and availability may be influenced by sludge treatments, such as drying and liming. A sludge similarly centrifuged with/without a flocculant was spiked with (14)C-labelled AC-SMX or ACM. Then, it was either limed (20% CaO) or/and dried under different laboratory conditions (1 week at ambient temperature; and 48 h at 40 or 80 °C).

Modeling the release of organic contaminants during compost decomposition in soil.

Composts, incorporated in soils as amendments, may release organic contaminants during their decomposition. COP-Soil is presented here as a new model to simulate the interaction between organic contaminants and compost, using one module for organic matter and one for organic pollutants, with these modules being linked by several assumptions. Published results of laboratory soil incubations using labeled carbon pollutants from compost were used to test the model for one polycyclic aromatic hydrocarbon (PAH), two surfactants and one herbicide.

Effect of rainfall regimes and mulch decomposition on the dissipation and leaching of S-metolachlor and glyphosate: a soil column experiment.

Background: Interception by plant residues is a major process affecting pesticide persistence and leaching in conservation agriculture. Dissipation and leaching of S-metolachlor and glyphosate was studied in repacked soil columns covered with a mulch of maize and lablab residues. The columns were submitted to two contrasting simulated rainfall regimes: one with light but frequent rain (LF) and one with less frequent but more intense rain (HI).

Adsorption and desorption behavior of selected pesticides as influenced by decomposition of maize mulch.

Assessing pesticide fate in conservation agricultural systems requires a detailed understanding of their interaction with decomposing surface crop residues (mulch). Adsorption and desorption behavior of glyphosate, s-metolachlor and epoxiconazole was investigated on maize mulch residues decomposed under laboratory and field conditions. Our conceptual approach included characterization of chemical composition and hydrophobicity of mulch residues in order to generate parameters to predict sorption behavior.

Remediation of polycyclic aromatic hydrocarbon (PAH) contaminated soil through composting with fresh organic wastes.

Introduction: Composting may enhance bioremediation of PAH-contaminated soils by providing organic substrates that stimulate the growth of potential microbial degraders. However, the influence of added organic matter (OM) together with the microbial activities on the dissipation of PAHs has not yet been fully assessed.

Materials And Methods: An in-vessel composting-bioremediation experiment of a contaminated soil amended with fresh wastes was carried out.

Preferential transport of Cryptosporidium parvum oocysts in variably saturated subsurface environments.

When oocysts of the protozoan Cryptosporidium parvum contaminate drinking water supplies, they can cause outbreaks of Cryptosporidiosis, a common waterborne disease. Of the different pathways by which oocysts can wind up in drinking water, one has received little attention to date; that is, because soils are often considered to be perfect filters, the transport of oocysts through the subsoil to groundwater is generally ignored. To evaluate the significance of this pathway, a series of laboratory experiments investigated subsurface transport of oocysts.