Adsorption and biodegradation of three selected endocrine disrupting chemicals in river-based artificial groundwater recharge with reclaimed municipal wastewater

Endocrine disrupting chemical(EDC) pollution in river-based artificial groundwater recharge using reclaimed municipal wastewater poses a potential threat to groundwater-based drinking water supplies in Beijing, China. Lab-scale leaching column experiments simulating recharge were conducted to study the adsorption, biodegradation, and transport characteristics of three selected EDCs: 17β-estradiol(E2), 17α-ethinylestradiol(EE2) and bisphenol A(BPA). The three recharge columns were operated under the conditions of continual sterilization recharge(CSR), continual recharge(CR), and wetting and drying alternative recharge(WDAR). The results showed that the attenuation effect of the EDCs was in the order of WDAR CR CSR system and E2 EE2 BPA, which followed first-order kinetics. The EDC attenuation rate constants were 0.0783, 0.0505, and 0.0479 m-1 for E2, EE2 and BPA in the CR system, respectively. The removal rates of E2, EE2, and BPA in the CR system were 98%, 96% and 92%, which mainly depended on biodegradation and were affected by water temperature.In the CR system, the concentrations of BPA, EE2, and E2 in soil were 4, 6 and 10 times higher than in the WDAR system, respectively. According to the DGGE fingerprints, the bacterial community in the bottom layer was more diverse than in the upper layer, which was related to the EDC concentrations in the water-soil system. The dominant group was found to be proteobacteria, including Betaproteobacteria and Alphaproteobacteria, suggesting that these microbes might play an important role in EDC degradation.     

Biological removal of antiandrogenic activity in gray wastewater and coking wastewater by membrane reactor process

A recombinant human androgen receptor yeast assay was applied to investigate the occurrence of antiandrogens as well as the mechanism for their removal during gray wastewater and coking wastewater treatment. The membrane reactor (MBR) system for gray wastewater treatment could remove 88.0% of antiandrogenic activity exerted by weakly polar extracts and 97.3% of that by moderately strong polar extracts, but only 32.5% of that contributed by strong polar extracts. Biodegradation by microorganisms in the MBR contributed to 95.9% of the total removal. After the treatment, the concentration of antiandrogenic activity in the effluent was still 1.05 μg flutamide equivalence (FEQ)/L, 36.2% of which was due to strong polar extracts. In the anaerobic reactor, anoxic reactor, and membrane reactor system for coking wastewater treatment, the antiandrogenic activity of raw coking wastewater was 78.6 mg FEQ/L, and the effluent of the treatment system had only 0.34 mg FEQ/L. The antiandrogenic activity mainly existed in the medium strong polar and strong polar extracts. Biodegradation by microorganisms contributed to at least 89.2% of the total antiandrogenic activity removal in the system. Biodegradation was the main removal mechanism of antiandrogenic activity in both the wastewater treatment systems.     

Can arbuscular mycorrhiza and fertilizer management reduce phosphorus runoff from paddy fields?

Our study sought to assess how much phosphorus (P) runoff from paddy fields could be cut down by fertilizer management and inoculation with arbuscular mycorrhizal fungi. A field experiment was conducted in Lalin River basin, in the northeast China: six nitrogen–phosphorus–potassium fertilizer levels were provided (0, 20%, 40%, 60%, 80%, and 100% of the recommended fertilizer supply), with or without inoculation with Glomus mosseae. The volume and concentrations of particle P (PP) and dissolved P (DP) were measured for each runoff during the rice growing season. It was found that the seasonal P runoff, including DP and PP, under the local fertilization was 3.7 kg/ha, with PP, rather than DP, being the main form of P in runoff water. Additionally, the seasonal P runoff dropped only by 8.9% when fertilization decreased by 20%; rice yields decreased with declining fertilization. We also found that inoculation increased rice yields and decreased P runoff at each fertilizer level and these effects were lower under higher fertilization. Conclusively, while rice yields were guaranteed arbuscular mycorrhizal inoculation and fertilizer management would play a key role in reducing P runoff from paddy fields.     

Comparison of three-dimensional fluorescence analysis methods for predicting formation of trihalomethanes and haloacetic acids

This work investigated the application of several fluorescence excitation–emission matrix analysis methods as natural organic matter(NOM) indicators for use in predicting the formation of trihalomethanes(THMs) and haloacetic acids(HAAs). Waters from four different sources(two rivers and two lakes) were subjected to jar testing followed by 24 hr disinfection by-product formation tests using chlorine. NOM was quantified using three common measures: dissolved organic carbon, ultraviolet absorbance at 254 nm, and specific ultraviolet absorbance as well as by principal component analysis, peak picking,and parallel factor analysis of fluorescence spectra. Based on multi-linear modeling of THMs and HAAs, principle component(PC) scores resulted in the lowest mean squared prediction error of cross-folded test sets(THMs: 43.7(μg/L)2, HAAs: 233.3(μg/L)2). Inclusion of principle components representative of protein-like material significantly decreased prediction error for both THMs and HAAs. Parallel factor analysis did not identify a protein-like component and resulted in prediction errors similar to traditional NOM surrogates as well as fluorescence peak picking. These results support the value of fluorescence excitation–emission matrix–principal component analysis as a suitable NOM indicator in predicting the formation of THMs and HAAs for the water sources studied.     

In situ soil water extraction: a review

The knowledge of the composition and fluxes of vadose zone water is essential for a wide range of scientific and practical fields, including water-use management, pesticide registration, fate of xenobiotics, monitoring of disposal from mining and industries, nutrient management of agricultural and forest ecosystems, ecology, and environmental protection. Nowadays, water and solute flow can be monitored using either in situ methods or minimally invasive geophysical measurements. In situ information, however, is necessary to interpret most geophysical data sets and to determine the chemical composition of seepage water. Therefore, we present a comprehensive review of in situ soil water extraction methods to monitor solute concentration, solute transport, and to calculate mass balances in natural soils. We distinguished six different sampling devices: porous cups, porous plates, capillary wicks, pan lysimeters, resin boxes, and lysimeters. For each of the six sampling devices we discuss the basic principles, the advantages and disadvantages, and limits of data acquisition. We also give decision guidance for the selection of the appropriate sampling system. The choice of material is addressed in terms of potential contamination, filtering, and sorption of the target substances. The information provided in this review will support scientists and professionals in optimizing their experimental set-up for meeting their specific goals.     

Tolerance (PICT) of the bacterial communities to copper in vineyards soils from Spain

To detect effects of Cu pollution, the Cu tolerance of soil bacterial communities extracted from several vineyards located in NW Spain was measured. Bacterial community tolerance was estimated by means of the thymidine (TdR) and leucine (Leu) incorporation techniques using either IC(50) values (the log of the metal concentration that reduced incorporation to 50%) or the percentage of activity at one specific Cu concentration (10(-6) mol L(-1)). The tolerance measurements by the TdR incorporation technique were similar to those obtained by the Leu incorporation method, indicating that the two methods were equivalent in terms of suitability for detecting the toxicity of Cu to soil bacterial communities. The two tolerance indices considered (IC50 values and percentage of activity) were closely correlated (r = 0.975, P < 0.001), showing that both were equally good in measuring Cu tolerance of the bacterial community. An increased bacterial community tolerance to Cu, indicating a pollution effect, was observed in vineyard soils with more than 100 mg Cu kg(-1) soil. Thus, the long-term use of Cu in vineyards has a toxic effect on the soil bacterial community, resulting in an increased tolerance. An effect of increased levels of Cu could not be detected when measuring bacterial community activity, pointing to the increased sensitivity to detect toxicity in field studies using tolerance measurements.     

Remediation of heavy metal-contaminated forest soil using recycled organic matter and native woody plants

The main aim of this study was to determine how the application of a mulch cover (a mixture of household biocompost and woodchips) onto heavy metal-polluted forest soil affects (i) long-term survival and growth of planted dwarf shrubs and tree seedlings and (ii) natural revegetation. Native woody plants (Pinus sylvestris, Betula pubescens, Empetrum nigrum, and Arctostaphylos uva-ursi) were planted in mulch pockets on mulch-covered and uncovered plots in summer 1996 in a highly polluted Scots pine stand in southwest Finland. Spreading a mulch layer on the soil surface was essential for the recolonization of natural vegetation and increased dwarf shrub survival, partly through protection against drought. Despite initial mortality, transplant establishment was relatively successful during the following 10 yr. Tree species had higher survival rates, but the dwarf shrubs covered a larger area of the soil surface during the experiment. Especially E. nigrum and P. sylvestris proved to be suitable for revegetating heavy metal-polluted and degraded forests. Natural recolonization of pioneer species (e.g., Epilobium angustifolium, Taraxacum coll., and grasses) and tree seedlings (P. sylvestris, Betula sp., and Salix sp.) was strongly enhanced on the mulched plots, whereas there was no natural vegetation on the untreated plots. These results indicate that a heavy metal-polluted site can be ecologically remediated without having to remove the soil. Household compost and woodchips are low-cost mulching materials that are suitable for restoring heavy metal-polluted soil.     

Integrating long-term stewardship goals into the remediation process: natural resource damages and the Department of Energy

The United States and other developed countries are faced with restoring and managing degraded ecosystems. Evaluations of the degradation of ecological resources can be used for determining ecological risk, making remediation or restoration decisions, aiding stakeholders with future land use decisions, and assessing natural resource damages. Department of Energy (DOE) lands provide a useful case study for examining degradation of ecological resources in light of past or present land uses and natural resource damage assessment (NRDA). We suggest that past site history should be incorporated into the cleanup and restoration phase to reduce the ultimate NRDA costs, and hasten resource recovery. The lands that DOE purchased over 50 years ago ranged from relatively undisturbed to heavily impacted farmland, and the impact that occurred from DOE occupation varies from regeneration of natural ecosystems (benefits) to increased exposure to several stressors (negative effects). During the time of the DOE releases, other changes occurred on the lands, including recovery from the disturbance effects of farming, grazing, and residential occupation, and the cessation of human disturbance. Thus, the injury to natural resources that occurred as a result of chemical and radiological releases occurred on top of recovery of already degraded systems. Both spatial (size and dispersion of patch types) and temporal (past/present/future land use and ecological condition) components are critical aspects of resource evaluation, restoration, and NRDA. For many DOE sites, integrating natural resource restoration with remediation to reduce or eliminate the need for NRDA could be a win-win situation for both responsible parties and natural resource trustees by eliminating costly NRDAs by both sides, and by restoring natural resources to a level that satisfies the trustees, while being cost-effective for the responsible parties. It requires integration of remediation, restoration, and end-state planning to a greater degree than is currently done at most DOE sites.     

Influence of x-ray diffraction sample preparation on quantitative mineralogy: implications for chromate waste treatment

Powders of chromite ore processing residue (COPR) were mineralogically evaluated using quantitative X-ray powder diffraction (XRPD) to illustrate the impacts of sample preparation procedures. Chromite ore processing residue is strongly alkaline, reactive, contains minerals of varying hardness and absorption coefficients, and exhibits significant amorphicity. This poses a challenge to produce powders for XRPD analysis that are sufficiently fine and of uniform particle size while avoiding mineral reactions and overgrinding effects. Dry, hand pulverization to different grain sizes, and wet, mechanical pulverization (micromilling) using four milling liquids (cyclohexane, isopropanol, ethanol, and water), and variable milling durations (up to 15 min) were evaluated. Micromilling with a light, nonpolar, highly evaporative liquid such as cyclohexane with a milling time of 5 min mitigated systematic errors such as microabsorption and preferred orientation as it produced finer and more uniform particle size distributions than the hand-pulverized powders, while simultaneously affording the least time for sample preparation. Conversely, the use of water as milling liquid resulted in extensive hydration reactions during sample preparation, causing mischaracterization and significant underestimation of its reactive brownmillerite content, which can complicate the remediation design process for COPR. Hand pulverization emerged as a necessary complement to quantify Cr(VI)-containing, softer minerals destroyed during mechanical milling, the quantification of which has also important implications for COPR treatment design. The findings of this study may be applicable in a variety of geochemically complicated and reactive environmental media (metal-contaminated soils, stabilized/solidified media, inorganic waste), and points to the importance of the sample preparation method to obtain reliable quantitative XRPD results.     

Microbial biomass governs enzyme activity decay during aging of worm-worked substrates through vermicomposting

Vermicomposting is the biooxidation and stabilization of organic matter involving the joint action of earthworms and microorganisms, thereby turning wastes into a valuable soil amendment called vermicompost. Studies have focused on the changes in the type of substrates available before and after vermicomposting, but little is known on how these changes take place, especially those changes related with maturation of vermicompost. This study investigated the effects of aging on the microbiological properties of fresh vermicompost produced from pig slurry by analyzing the substrate after the earthworms had left it. We incubated 16-wk-old vermicompost and sampled it after 15, 30, 45, and 60 d analyzing microbial biomass and activity (assessed as microbial biomass N and basal respiration respectively) and four enzymatic activities (beta-glucosidase, cellulase, protease, and alkaline phosphatase). Aging of vermicompost resulted in decreases of microbial biomass and activity. Three of the four enzymes analyzed also showed decrease. An initial increase followed by a rapid decrease in alkaline phosphatase was also recorded. High and significant correlations between microbial biomass and beta-glucosidase (r = 0.62, P < 0.001), cellulase (r = 0.56, P < 0.01), and protease (r = 0.82, P < 0.001) were found. Results suggest that there may be two steps involved in the aging dynamics of vermicompost with regards to extracellular enzyme activity; the first step was characterized by a decrease in microbial populations, which resulted in a reduction in the synthesis of new enzymes. The second step was the degradation of the pool of remaining enzymes. This dynamic does not seem to be affected by earthworms because similar decaying patterns of microbial biomass and activity were found in substrate where earthworms were present.