Phytotoxicity of 15 common pharmaceuticals on the germination of Lactuca sativa and photosynthesis of Chlamydomonas reinhardtii

Pharmaceuticals reach terrestrial environments through the application of treated wastewaters and biosolids to agricultural soils. We have investigated the toxicity of 15 common pharmaceuticals, classified as nonsteroidal anti-inflammatory drugs (NSAIDs), blood lipid-lowering agents, β-blockers and antibiotics, in two photosynthetic organisms. Twelve pharmaceuticals caused inhibitory effects on the radicle and hypocotyl elongation of Lactuca sativa seeds. The EC₅₀ values obtained were in the range of 170–5656 mg L⁻¹ in the case of the radicle and 188–4558 mg L⁻¹ for the hypocotyl. Propranolol was the most toxic drug for both root and hypocotyl elongation, followed by the NSAIDs, then gemfibrozil and tetracycline. Other effects, such as root necrosis, inhibition of root growth and curly hairs, were detected. However, even at the highest concentrations tested (3000 mg L⁻¹), seed germination was not affected. NSAIDs decreased the photosynthetic yield of Chlamydomonas reinhardtii, but only salicylic acid showed EC₅₀ values below 1000 mg L⁻¹. The first effects detected at low concentrations, together with the concentrations found in environmental samples, indicate that the use of biosolids and wastewaters containing pharmaceuticals should be regulated and their compositions assessed in order to prevent medium- and long-term impacts on agricultural soils and crops.

     

Phytoextraction of Pb,Cr, Ni,and Zn using the aquatic plant Limnobium laevigatum and its potential use in the treatment of wastewater

In order to study the bioaccumulation of Pb, Cr, Ni, and Zn and the stress response, the floating aquatic plant Limnobium laevigatum was exposed to increasing concentrations of a mixture of these metals for 28 days, and its potential use in the treatment of wastewater was evaluated. The metal concentrations of the treatment 1 (T1) were Pb 1 μg L⁻¹, Cr 4 μg L⁻¹, Ni 25 μg L⁻¹, and Zn 30 μg L⁻¹; of treatment 2 (T2) were Pb 70 μg L⁻¹, Cr 70 μg L⁻¹, Ni 70 μg L⁻¹, and Zn 70 μg L⁻¹; and of treatment 3 (T3) were Pb 1000 μg L⁻¹, Cr 1000 μg L⁻¹, Ni 500 μg L⁻¹, and Zn 100 μg L⁻¹, and there was also a control group (without added metal). The accumulation of Pb, Cr, Ni, and Zn in roots was higher than in leaves of L. laevigatum, and the bioconcentration factor revealed that the concentrations of Ni and Zn in the leaf and root exceeded by over a thousand times the concentrations of those in the culture medium (2000 in leaf and 6800 in root for Ni; 3300 in leaf and 11,500 in root for Zn). Thus, this species can be considered as a hyperaccumulator of these metals. In general, the changes observed in the morphological and physiological parameters and the formation of products of lipid peroxidation of membranes during the exposure to moderate concentrations (T2) of the mixture of metals did not cause harmful effects to the survival of the species within the first 14 days of exposure. Taking into account the accumulation capacity and tolerance to heavy metals, L. laevigatum is suitable for phytoremediation in aquatic environments contaminated with moderated concentrations of Cr, Ni, Pb, and Zn in the early stages of exposure.

     

Toxicity and genotoxic evaluations in African catfish Clarias gariepinus (Burchell 1822) exposed to Act Force Gold®, Butaforce®, and Atraforce®

Act Force Gold^®, Butaforce^®, and Atraforce^® are among the most commonly used pesticides in Nigeria. The lethal concentrations and the respective toxic units for the three pesticides were determined. The genotoxic effects of the three pesticides were investigated in the red blood cells of Clarias gariepinus using micronucleus (MN) assay. The 96 h LC₅₀ was 4.75, 4.84, and 54.74 mg L⁻¹ for Act Force Gold^®, Butaforce^®, and Atraforce^®, respectively. The toxic units in ascending order of toxicity were 1.83, 20.66, and 21.05 for Act Force Gold^®, Butaforce^®, and Atraforce^® respectively. The estimated safe levels based on NAS/NAE varied from 4.75 × 10⁻¹–4.75 × 10⁻⁵ in Act Force Gold^® through 4.64 × 10⁻¹–4.85 × 10⁻⁵ in Butaforce^® to 5.74–5.74 × 10⁻⁵ in Atraforce^®. Fish specimens were exposed to the pesticides and sampling was done at regular intervals at days 1, 7, 14, and 21 and after another 7-day recovery period. The results obtained indicated concentration- and duration-dependent increase in % MN formation with maximum values of 3.40 ± 0.25 for Act Force Gold^® on day 14 and 3.05 ± 0.36 and 2.35 ± 0.14 for Butaforce^® and Atraforce^® respectively on day 7 of exposure. The 7-day recovery period could not reverse the trend as the % MN values obtained were significantly different from the control. The results further support the use of MN assay in assessing the toxicity of aquatic pollutants and can be used in the monitoring of aquatic ecosystems.

     

Acute toxicity assessment of explosive-contaminated soil extracting solution by luminescent bacteria assays

Explosive-contaminated soil is harmful to people’s health and the local ecosystem. The acute toxicity of its extracting solution was tested by bacterial luminescence assay using three kinds of luminescent bacteria to characterize the toxicity of the soil. An orthogonal test L ₁₆ (4⁵) was designed to optimize the soil extracting conditions. The optimum extracting conditions were obtained when the ultrasonic extraction time, ultrasonic extraction temperature, and the extraction repeat times were 6 h, 40 °C, and three, respectively. Fourier transform infrared spectroscopy (FTIR) results showed that the main components of the contaminated soil’s extracting solution were 2,4-dinitrotoluene-3-sulfonate (2,4-DNT-3-SO₃ ⁻); 2,4-dinitrotoluene-5-sulfonate (2,4-DNT-5-SO₃ ⁻); and 2,6-dinitrotoluene (2,6-DNT). Compared with Photobacterium phosphoreum and Vibrio fischeri, Vibrio qinghaiensis sp. Nov. is more suitable for assessing the soil extracting solution’s acute toxicity. Soil washing can remove most of the contaminants toxic to luminescent bacterium Vibrio qinghaiensis sp. Nov., suggesting that it may be a potential effective remediation method for explosive-contaminated soil.

     

Impact of PCB-118 and transformer oil toxicity on anaerobic digestion of sludge: Anaerobic toxicity assay results

In this study, possible toxicity of increasing doses of PCB-118 and transformer oil (TO) on anaerobic sludge digestion was investigated. For this purpose, five different sets of reactors were prepared in which four different PCB-118 concentration (1, 10, 20, and 30 mg L⁻¹) and three different TO concentration (0.38, 0.76, and 1.52 g L⁻¹) were applied. Throughout the study, biogas production and composition, pH, TS, VS, and COD as well as PCB concentration were monitored. Toxicity was investigated by anaerobic toxicity assay (ATA) evaluating the reduction in methane production. A notable inhibition was observed mostly in 30 mg L⁻¹ PCB reactors. A negative influence of PCB-118 and TO was observed on COD and solids removal. A maximum of 26.5% PCB-118 removal was attained.     

Enhanced excess sludge hydrolysis and acidification in an activated sludge side-stream reactor process with single-stage sludge alkaline treatment: a pilot scale study

A pilot-scale side-stream reactor process with single-stage sludge alkaline treatment was employed to systematically investigate characteristics of excess sludge hydrolysis and acidification with alkaline treatment and evaluate feasibility of recovering a carbon source (C-source) from excess sludge to enhance nutrient removal at ambient temperature. The resulting C-source and volatile fatty acid specific yields reached 349.19 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) d⁻¹ and 121.3 mg COD/g VSS d⁻¹, respectively, the process had excellent C-source recovery potential. The propionic-to-acetic acid ratio of the recovered C-source was 3.0 times that in the influent, which beneficially enhanced biological phosphorus removal. Large populations and varieties of hydrolytic acid producing bacteria cooperated with alkaline treatment to accelerate sludge hydrolysis and acidification. Physicochemical characteristics indicated that recovered C-source was derived primarily from extracellular polymeric substances hydrolysis rather than from cells disruption during alkaline treatment. This study showed that excess sludge as carbon source was successfully recycled by alkaline treatment in the process.

     

Combined toxic impacts of thiamethoxam and four pesticides on the rare minnow (Gobiocypris rarus)

To examine pesticide mixture toxicity to aqueous organisms, we assessed the single and combined toxicities of thiamethoxam and other four pesticides (chlorpyrifos, beta-cypermethrin, tetraconazole, and azoxystrobin) to the rare minnow (Gobiocypris rarus). Data from 96-h semi-static toxicity assays of various developmental phases (embryonic, larval, juvenile, and adult phases) showed that beta-cypermethrin, chlorpyrifos, and azoxystrobin had the highest toxicities to G. rarus, and their LC₅₀ values ranged from 0.0031 to 0.86 mg a.i. L^?1, from 0.016 to 6.38 mg a.i. L^?1, and from 0.39 to 1.08 mg a.i. L^?1, respectively. Tetraconazole displayed a comparatively high toxicity, and its LC₅₀ values ranged from 3.48 to 16.73 mg a.i. L^?1. By contrast, thiamethoxam exhibited the lowest toxic effect with LC₅₀ values ranging from 37.85 to 351.9 mg a.i. L^?1. Rare minnow larvae were more sensitive than embryos to all the pesticides tested. Our data showed that a pesticide mixture of thiamethoxam–tetraconazole elicited synergetic toxicity to G. rarus. Moreover, pesticide mixtures containing beta-cypermethrin in combination with chlorpyrifos or tetraconazole also had synergetic toxicities to fish. The majority of pesticides are presumed to have additive toxicity, while our data emphasized that the concurrent existence of some chemicals in the aqueous circumstance could cause synergetic toxic effect, leading to severe loss to the aqueous environments in comparison with their single toxicities. Thence, the synergetic impacts of chemical mixtures should be considered when assessing the ecological risk of chemicals.

     

Nutrient removal from biogas slurry and biogas upgrading by microalgae-fungi-bacteria co-cultivation under different carbon nanotubes concentration

In this study, Chlorella vulgaris, Ganoderma lucidum, and endophytic bacteria were co-cultivated with the stimulation of strigolactone analogs GR24 to prepare pellets. During the purification of biogas slurry and biogas, multi-walled carbon nanotubes (MWCNTs) were introduced to enhance the removal efficiencies of nutrients and CO₂. The results showed that both GR24 and MWCNTs affected the purification of biogas slurry and biogas. The maximum chemical oxygen demand, total nitrogen, total phosphorus, and CO₂ removal efficiencies of the Chlorella vulgaris-Ganoderma lucidum-endophytic bacterial symbionts were 82.57 ± 7.96% (P < 0.05), 82.14 ± 7.87% (P < 0.05), 84.27 ± 7.96% (P < 0.05), and 63.93 ± 6.22% (P < 0.05), respectively, with the induction of 10⁻⁹ M GR24 and 1 mg L⁻¹ MWCNTs. Moreover, the growth and photosynthetic performance of the symbionts were consistent with the removal effects. The Chlorella vulgaris-Ganoderma lucidum-endophytic bacterial symbionts obtained high growth rates and enzyme activity with the maximum growth rate of 0.365 ± 0.03 d⁻¹, mean daily productivity of 0.182 ± 0.016 g L⁻¹ d⁻¹, and carbonic anhydrase activity of 31.07 ± 2.75 units, respectively. These results indicated that an appropriate concentration of GR24 and MWCNTs could promote the growth of symbionts, reinforce the purification effects of biogas slurry and biogas, and provide a new idea for the simultaneous purification of wastewater and biogas.

     

Application of pier waste sludge for catalytic activation of proxy-monosulfate and phenol elimination from a petrochemical wastewater

This investigation aimed to remove phenol from real wastewater (taken from a petrochemical company) by activating peroxy-monosulfate (PMS) using catalysts extracted from pier waste sludge. The physical and chemical properties of the catalyst were evaluated by FE-SEM/EDS, XRD, FTIR, and TGA/DTG tests. The functional groups of O–H, C–H, CO₃^2?, C–H, C–O, N–H, and C–N were identified on the catalyst surface. Also, the crystallinity of the catalyst before and after reaction with petrochemical wastewater was 103.4 nm and 55.8 nm, respectively. Operational parameters of pH (3–9), catalyst dose (0–100 mg/L), phenol concentration (50–250 mg/L), and PMS concentration (0–250 mg/L) were tested to remove phenol. The highest phenol removal rate (94%) was obtained at pH=3, catalyst dose of 80 mg/L, phenol concentration of 50 mg/L, PMS concentration of 150 mg/L, and contact time of 150 min. Phenol decomposition in petrochemical wastewater followed the first-order kinetics (k> 0.008 min^?1, R²> 0.94). Changes in pH factor were very effective on phenol removal efficiency, and maximum efficiency (≈83%) was achieved in pH 3. The catalyst stability test was performed for up to five cycles, and phenol removal in the fifth cycle was reduced to 42%. Also, the energy consumption in this study was 77.69 kW h/m³. According to the results, the pier waste sludge catalyst/PMS system is a critical process for eliminating phenol from petrochemical wastewater.

     

The biological responses and metal phytoaccumulation of duckweed Spirodela polyrhiza to manganese and chromium

The phytoaccumulation ability of duckweed Spirodela polyrhiza on manganese (Mn) and chromium (Cr) was assessed by exposing the plant to various concentrations of single or dual metals (5–70 mg L^?1 Mn, 2–12 mg L^?1 Cr(VI)) under laboratory conditions. The results showed that S. polyrhiza can tolerate Mn at high concentrations of up to 70 mg L^?1, and its growth rate was barely affected by Mn. The effects of Cr on S. polyrhiza growth were dose-dependent, and the growth was completely inhibited in the presence of 12 mg L^?1 Cr. Analysis of metal content in the plant biomass revealed a high accumulation of Mn (up to 15.75 mg per g of duckweed dry weight). The Cr bioaccumulation (from below detection limit to 2.85 mg Cr (11.84 mg Cr₂O₇ ^2?) per g of duckweed dry weight) increased with cultivation time and metal concentration in the medium. Further study with the concurrence of Mn and Cr showed increased toxicity to plant growth and photosynthesis. The metal accumulations in the dual metal treatments were also significantly decreased as compared to the single metal treatments. Nevertheless, the phytoaccumulation of these two metals in S. polyrhiza in the dual metal treatments were still comparable to or higher than in previous reports. Thus, it was concluded that duckweed S. polyrhiza has the potential to be used as a phytoremediator in aquatic environments for Mn and Cr removal.

     

Improved treatment approach for the removal of aromatic compounds using polymeric beads in Fenton pretreatment and biological oxidation

An improved approach based on the use of iron-doped polymeric beads (IPB) as Fenton catalyst in the pretreatment and biomass-doped polymeric bead (BPB) in the biological oxidation has been reported for the removal of different aromatic mixtures present as pollutants in the aqueous solutions. Degradation has been investigated at fixed loading of IPB as 2.5 % weight basis and varying loading of hydrogen peroxide so as to understand the effect of oxidant loading on the extent of degradation. It has been observed that the maximum removal efficiency as 75.5, 81.4, and 59.1 % was obtained for the benzene-toluene-naphthalene-xylene (BTNX), benzene-toluene-ethylbenzene-xylene (BTEX), and benzene-toluene-naphthalene-p-nitrophenol (BTNp-NP) mixtures, respectively, at a 40-min pretreatment and optimum pH of 3.5. The biodegradability index was also observed in the favorable range of 0.4 to 0.5 after the pretreatment at optimum H₂O₂ loading of 1.5 g L⁻¹. Maximum COD removal efficiency of 99.2, 99.3, and 99.6 % was obtained using the biological oxidation treatment for 40 h for the case of BTNX, BTEX, and BTNp-NP mixtures, respectively. Analysis of kinetic models revealed that degradation followed three distinct stages based on fitting of the three-stage model and BPB was found to be more efficient as compared to the primary activated sludge (PAS) and modified activated sludge (MAS). Reusability studies confirmed that both IPB and BPB were effective over many cycles giving stable performance during degradation without leaching of Fe³⁺ ions into the solution.

     

Responses of antioxidant status and Na+–K+-ATPase activity in gill of rainbow trout,Oncorhynchus mykiss,chronically treated with carbamazepine

In recent years, chemical pollution by the residual pharmaceuticals has been increasingly important issue due to its widely present in the aquatic environment. However, the toxicological effects of residual pharmaceuticals on fish have not been adequately researched. The aim of this work is to investigate the toxic effect of CBZ, an anticonvulsant drug commonly present in aquatic environment, on antioxidant status and Na⁺–K⁺-ATPase in gill of rainbow trout exposed to sublethal CBZ (1.0 μg L⁻¹, 0.2 mg L⁻¹ and 2.0 mg L⁻¹) for 7, 21 and 42 d. After prolonged exposure of CBZ at higher test concentration (0.2 or 2.0 mg L⁻¹), oxidative stress was apparent as reflected by the significant higher LPO and CP levels in fish gill, as well as the significant inhibition of antioxidant enzymes activities including SOD, CAT, GR and GPx. Besides, reduced glutathione level and Na⁺–K⁺-ATPase activity were significantly lower than those of the control after 42 d of exposure to CBZ at higher test concentration (0.2 or 2.0 mg L⁻¹). The results of this study indicate that chronic exposure of CBZ has altered multiple physiological indices in fish gill; however, before those parameters are used as special biomarkers for monitoring residual pharmaceuticals in aquatic environment, more detailed experiments in laboratory need to be performed in the future.     

Toxicity of 58 substituted anilines and phenols to algae Pseudokirchneriella subcapitata and bacteria Vibrio fischeri: comparison with published data and QSARs

A congeneric set of 58 substituted anilines and phenols was tested using the 72-h algal growth inhibition assay with Pseudokirchneriella subcapitata and 15-min Vibrio fischeri luminescence inhibition assay. The set contained molecules substituted with one, two or three groups chosen from -chloro, -methyl or -ethyl. For 48 compounds there was no REACH-compatible algal toxicity data available before. The experimentally obtained EC50 values (mg L⁻¹) for algae ranged from 1.43 (3,4,5-trichloroaniline) to 197 (phenol) and for V. fischeri from 0.37 (2,3,5-trichlorophenol) to 491 (aniline). Only five of the tested 58 chemicals showed inhibitory effect to algae at concentrations >100 mg L⁻¹, i.e. could be classified as “not harmful”, 32 chemicals as “harmful” (10-100 mg L⁻¹) and 21 as “toxic” (1-10 mg L⁻¹). The occupied para-position tended to increase toxicity whereas most of the ortho-substituted congeners were the least toxic. As a rule, the higher the number of substituents the higher the hydrophobicity and toxicity. However, in case of both assays, the compounds of similar hydrophobicity showed up to 30-fold different toxicities. There were also assay/organism dependent tendencies: phenols were more toxic than anilines in the V. fischeri assay but not in the algal test. The comparison of the experimental toxicity data to the data available from the literature as well as to QSAR predictions showed that toxicity of phenols to algae can be modeled based on hydrophobicity, whereas the toxicity of anilines to algae as well as toxicity of both anilines and phenols to V. fischeri depended on other characteristics in addition to logK_ow.     

Dual mechanochemical immobilization of heavy metals and decomposition of halogenated compounds in automobile shredder residue using a nano-sized metallic calcium reagent

Simultaneous immobilization of heavy metals and decomposition of halogenated organic compounds in different fractions of automobile shredder residue (ASR) were achieved with a nano-sized metallic calcium through a 60-min ball milling treatment. Heavy metal (HM) immobilization and chlorinated/brominated compound (CBC) decomposition efficiencies both reached 90–100 %, after ball milling with nanometallic calcium/calcium oxide (Ca/CaO) dispersion, regardless of ASR particle size (1.0, 0.45–1.0, and 0.250 mm). Concentrations of leachable HMs substantially decreased to a level lower than the regulatory standard limits (Co and Cd 0.3 mg L⁻¹; Cr 1.5 mg L⁻¹; Fe, Pb, and Zn 3.0 mg L⁻¹; Mn and Ni 1 mg L⁻¹) proposed by the Korean hazardous waste elution standard regulatory threshold. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) element maps/spectra showed that while the amounts of HMs and CBCs detectable in ASR significantly decreased, the calcium mass percentage increased. X-ray powder diffraction (XRD) patterns indicate that the main fraction of enclosed/bound materials on ASR includes Ca-associated crystalline complexes that remarkably inhibit HM desorption and simultaneously transform dangerous CBCs into harmless compounds. The use of a nanometallic Ca/CaO mixture in a mechanochemical process to treat hazardous ASR (dry conditions) is an innovative approach to remediate cross-contaminated residues with heavy metals and halogenated compounds.

     

Measurement and analysis of atmospheric ammonia emissions from anaerobic lagoons

Ammonia-nitrogen flux (NH₃-N=(14/17)NH₃) was determined from six anaerobic swine waste storage and treatment lagoons (primary, secondary, and tertiary) using the dynamic chamber system. Measurements occurred during the fall of 1998 through the early spring of 1999, and each lagoon was examined for approximately one week. Analysis of flux variation was made with respect to lagoon surface water temperature (∼15 cm below the surface), lagoon water pH, total aqueous phase NH_x(=NH₃+NH₄⁺) concentration, and total Kjeldahl nitrogen (TKN). Average lagoon temperatures (across all six lagoons) ranged from approximately 10.3 to 23.3^°C. The pH ranged in value from 6.8 to 8.1. Aqueous NH_x concentration ranged from 37 to 909 mg N l⁻¹, and TKN varied from 87 to 950 mg N l⁻¹. Fluxes were the largest at the primary lagoon in Kenansville, NC (March 1999) with an average value of 120.3 μg N m⁻² min⁻¹, and smallest at the tertiary lagoon in Rocky Mount, NC (November 1998) at 40.7 μg N m⁻² min⁻¹. Emission rates were found to be correlated with both surface lagoon water temperature and aqueous NH_x concentration. The NH₃-N flux may be modeled as ln(NH₃-N flux)=1.0788+0.0406T_L+0.0015([NH_x]) (R²=0.74), where NH₃-N flux is the ammonia flux from the lagoon surface in μg N m⁻² min⁻¹, T_L is the lagoon surface water temperature in ^°C, and [NH_x] is the total ammonia-nitrogen concentration in mg N l⁻¹.     

Macro-fungal (Agaricus bisporus) wastes as an adsorbent in the removal of the acid red 97 and crystal violet dyes from ideal colored effluents

The wastes from the macro-fungus Agaricus bisporus were used as an eco-friendly and low-cost adsorbent for the treatment of colored effluents containing the recalcitrant dyes, acid red 97 (AR97) and crystal violet (CV). The macro-fungal waste presented an amorphous structure, composed of particles with different sizes and shapes. Also, it presents typical functional chemical groups of proteins and carbohydrates with a point of zero charge of 4.6. The optimum conditions for the dosage were found to be as follows: 0.5 g L⁻¹ with an initial pH at 2.0 for the AR97 and 8.0 for the CV. From the kinetic test, it was found that it took 210 min and an adsorption capacity of 165 mg g⁻¹ for the AR97. Concerning the CV kinetics, it took 120 min to reach the equilibrium and it achieved an adsorption capacity of 165.9 mg g⁻¹. The Elovich model was the most proper model for describing the experimental data, achieving an R² ≥ 0.997 and MSE ≤ 36.98 (mg g⁻¹)². The isotherm curves were best represented by the Langmuir model, predicting maximum adsorption capacity of 372.69 and 228.74 mg g⁻¹ for the AR97 and CV, respectively. The process was spontaneous and favorable for both dyes. The ∆H⁰ values were 9.53 and 10.69 kJ mol⁻¹ for AR97 and CV, respectively, indicating physical and endothermic adsorption. Overall, the wastes from Agaricus bisporus have the potential to adsorb cationic and anionic dyes, thus solving environmental problems related to water quality and residue disposal.

     

好氧颗粒污泥降解苯酚

以人工配水启动SBR,逐步提高进水苯酚浓度,探究好氧颗粒污泥对苯酚的降解能力,同时分析苯酚对好氧颗粒污泥特性的影响。经过55 d的运行,进水苯酚浓度逐渐增到3 000 mg/L,苯酚、COD及NH+4-N去除率分别达到了98.33%、97.27%和57.58%,好氧颗粒污泥表现出对苯酚的良好的去除能力。扫描电镜照片显示投加苯酚后的颗粒污泥表面更加光滑,结构更为紧凑。胞外聚合物红外光谱分析表明投加苯酚前后好氧颗粒污泥EPS的主要组分没有明显改变。苯酚毒性刺激了颗粒污泥分泌更多胞外聚合物,胞外聚合物中多糖含量由初始的12.70 mg/g VSS增加到35.17 mg/g VSS,蛋白含量由4.93 mg/g VSS增加到8.01 mg/g VSS。投加苯酚后的污泥粒径明显增大,主要污泥粒径由0.5~2.0 mm增大到2.0 mm以上。     

Responses of phytoplankton functional groups to environmental factors in the Pearl River,South China

The variations of phytoplankton functional groups and their correlation with environmental factors, as well as the applicability of phytoplankton functional groups to serve as biological water quality indicator in the Pearl River, South China, were studied in the present study. A total of 96 samples were collected and divided into 21 functional groups from September 2016 to July 2017. The phytoplankton functional groups P and G were dominant during the investigation, and their biomass contributing was ranged 0.06 to 89.07%, the average 30.73%, and ranged 1.47 to 62.40%, the average 9.33% of the total biomass, respectively. The results showed environmental estrogens—BPA (bisphenol A), E2 (17β-estradiol), E1 (estrone), 4-t-OP (4-tert-octylphenol), 4-NP (nonylphenol), TCS (triclosan), and TCC (triclocarban)—in the Pearl River were significantly different, and with average values of 269.30 ng L^?1, 2.76 ng L^?1, 4.24 ng L^?1, 53.68 ng L^?1, 952.72 ng L^?1, 16.79 ng L^?1, and 8.61 ng L^?1, respectively. This was likely responsible for the differences in the phytoplankton functional groups. We observed positive correlations between P and A, and G and J. Functional groups P biomass decreased significantly with functional groups L_M increased, and functional groups M and J with X2. We found positive correlations between functional group G and concentrations of E1 and TCC; functional group A and total nitrogen (TN), 4-NP, 4-t-OP, and E2; functional groups L_M and L1 and total suspended particles, BPA, and TCS; and functional group G and negative total phosphorus (TP), pH, and TCS. The study showed that TN, TP, and the environmental estrogens in the aquatic ecosystems were correlation with phytoplankton functional groups type, and affected the ecological balance in aquatic environments.

     

Mercury emissions from automobiles using gasoline,diesel, and LPG

Mercury (Hg) emissions from gasoline, diesel, and liquefied petroleum gas (LPG) vehicles were measured and speciated (particulate, oxidized, and elemental mercury). First, three different fuel types were analyzed for their original Hg contents; 571.1±4.5 ng L⁻¹ for gasoline, 185.7±2.6 ng L⁻¹ for diesel, and 1230.3±23.5 ng L⁻¹ for LPG. All three vehicles were then tested at idling and driving modes. Hg in the exhaust gas was mostly in elemental form (Hg⁰), and no detectable levels of particulate (Hg^p) or oxidized (Hg²⁺) mercury were measured. At idling modes, Hg concentrations in the exhaust gas of gasoline, diesel, and LPG vehicles were 1.5–9.1, 1.6–3.5, and 10.2–18.6 ng m⁻³, respectively. At driving modes, Hg concentrations were 3.8–16.8 ng m⁻³ (gasoline), 2.8–8.5 ng m⁻³ (diesel), and 20.0–26.9 ng m⁻³ (LPG). For all three vehicles, Hg concentrations at driving modes were higher than at idling modes. Furthermore, Hg emissions from LPG vehicle was highest of all three vehicle types tested, both at idling and driving modes, as expected from the fact that it had the highest original fuel Hg content.     

Immunoassays as high-throughput tools: Monitoring spatial and temporal variations of carbamazepine,caffeine and cetirizine in surface and wastewaters

Carbamazepine (CBZ), caffeine and cetirizine were monitored by enzyme-linked immunosorbent assays (ELISAs) in surface and wastewaters from Berlin, Germany. This fast and cost-efficient method enabled to assess the spatial and temporal variation of these anthropogenic markers in a high-throughput screening. CBZ and cetirizine were detected by the same antibody, which selectively discriminates between both compounds depending on the pH value used in the incubation step. To our best knowledge, this is the first dual-analyte immunoassay working with a single antibody.The frequent sampling with 487 samples being processed allowed for the repeated detection of unusually high concentrations of CBZ and caffeine. ELISA results correlate well with the ones obtained by liquid chromatography tandem mass spectrometry (LC-MS/MS). Caffeine concentrations found in surface waters were elevated by combined sewer overflows after stormwater events. During the hay fever season, the concentrations of the antihistamine drug cetirizine increased in both surface and wastewaters.Caffeine was almost completely removed during wastewater treatment, while CBZ and cetirizine were found to be more persistent. The maximum concentrations of caffeine, CBZ and cetirizine found in influent wastewater by LC–MS/MS were 470, 5.0 and 0.49 μg L⁻¹, while in effluent wastewater the concentrations were 0.22, 4.5 and 0.51 μg L⁻¹, respectively. For surface waters, concentrations up to 3.3, 4.5 and 0.72 μg L⁻¹ were found, respectively.