The 2,4-dichlorophenoxyacetic acid (2,4-D) is used worldwide in agriculture as a selective herbicide. It has been shown to produce a wide range of adverse effects on the health of both animals and humans from embryotoxicity and teratogenicity to neurotoxicity. In the present study, we have examined the effect of 2,4-D on male reproductive function of rats. Male Wistar rats received daily by force-feeding 100 or 200 mg of 2,4-D/kg body weight for 30 consecutive days. Rats exposed to 100 and 200 mg of 2,4-D/kg showed a significant decrease in body weights only after 24 days of treatment and in relative weights of testis, seminal vesicles and prostate at killing day, when compared with controls. Moreover, a decrease in testosterone and an increase in FSH and LH serum levels were detected in treated rats. Besides, exposure to this herbicide induced pronounced testicular histological alterations with enlarged intracellular spaces, tissue loosening and dramatic loss of gametes in the lumen of the seminiferous tubules. In addition, a decreased motility and a number of epididymal spermatozoa with an increased sperm abnormality rate were found in treated rats in comparison with control. With the highest dose, histological observations of seminal vesicles indicated a considerable decrease of secretions in the lumen, a thinness of the muscle layer surrounding the epithelium with branched mucosal crypts and reduced luminal space. In prostate, the heights of the cells decreased while acinar lumen were enlarged and they lost the typical invaginations. Our results suggest that a subacute treatment of 2,4-D promotes reproductive system toxicity.

Research has demonstrated that the feeding pattern of synthetic wastewater plays an important role in sludge characteristics during biological wastewater treatment. Although considerable research has been devoted to synthetic wastewater, less attention has been paid to industrial wastewater. In this research, three different feeding strategies were applied during the treatment of tank truck cleaning (TTC) water. This industry produces highly variable wastewaters that are often loaded with hazardous chemicals, which makes them challenging to treat with activated sludge (AS). In this study, it is shown that the feeding pattern has a significant influence on the settling characteristics. Pulse feeding resulted in AS with a sludge volume index (SVI) of 68 ± 15 mL gMLSS⁻¹. Slowly and continuously fed AS had to contend with unstable SVI values that fluctuated between 100 and 600 mL gMLSS⁻¹. These fluctuations were clearly caused by the feeding solution. The obtained settling characteristics are being supported by the microscopic analysis, which revealed a clear floc structure for the pulse fed AS. Ecotoxicological effluent assessment with bacteria, Crustacea and algae identified algae as the most sensitive organism for all effluents from all different reactors. Variable algae growth inhibitions were measured between the different reactors. The chemical and ecotoxicological effluent quality was comparable between the reactors.

This research evaluated the feasibility of using vetiver plantlets (Vetiveria zizanioides (L.) Nash) on a floating platform with aeration to degrade phenol (500 mg/L) in illegally dumped industrial wastewater (IDIWW). The IDIWW sample was from the most infamous illegal dumping site at Nong Nae subdistrict, Phanom Sarakham district, Chachoengsao province, Thailand. Laboratory results suggested that phenol degradation by vetiver involves two phases: Phase I, phytopolymerization and phyto-oxidation assisted by root-produced peroxide (H₂O₂) and peroxidase (POD), followed by phase II, a combination of phase I with enhanced rhizomicrobial degradation. The first 360–400 h of phenol degradation were dominated by phytopolymerization and phyto-oxidation yielding particulate polyphenols (PPP) or particulate organic matter (POM) as by-products, while phenol decreased to around 145 mg/L. In Phase II, synergistically, rhizomicrobial growth was ∼100-folds greater on the roots of the vetiver plantlets than in the IDIWW and participated in the microbial degradation of phenol at this lower phenol concentration, increasing the phenol degradation rate by more than three folds. This combination of phytochemical and rhizomicrobiological processes eliminated phenol in IDIWW in less than 766 h (32 days), while without the vetiver plantlets, phenol degradation by aerated microbial degradation alone may require 235 days. To our knowledge, this is the first that systematically reveals the complete phenol degradation mechanism by vetiver plantlets in real aerated wastewater.

Three amendments including limestone, MnO₂ and natural zeolite were assessed for their stabilisation effects on Zn, Cu, Pb and Cd in sediment of east Dongting Lake, mid-south China. The metals were first subject to pollution status and potential ecological risk assessment to identify the current and potential hazards to ecology. Speciation of the metals in the sediment treated with amendments was then carried out by BCR sequential extraction procedure in order to evaluate metal contents and their potential mobility. The total concentrations of Zn, Cu, Pb and Cd in the east Dongting Lake were all above the means of national stream sediment and soil guidelines. The sediments were currently unpolluted to moderately pollute with Zn, Cu and Pb and strongly polluted with Cd. Zinc, Cu and Pb posed low risks to the lake ecosystem, and Cd had the highest potential risk that caused the overall risk of the sediment to be high or very high. Limestone stabilised Cu and Zn effectively, yet mobilisation of Cd and Pb by such amendment was also observed. MnO₂ effectively reduced the extractable Cd and Pb. The effect of natural zeolite on metal stabilisation in the sediment was least notable. Limestone and MnO₂ showed higher metal stabilisation efficiencies than zeolite. However, a single amendment is unable to achieve the goal of stabilisation for all metals. A combination use of the advantageous amendments or a search of a stronger stabiliser should be the interest of our future study.

Cytostatics are part of the forefront research topics due to their high prescription, high toxicity, and the lack of effective solutions to stop their entrance and spread in the environment. Among them, 5-Fluorouracil (5-Fu) has received particular attention because is one of the most prescribed active substances in chemotherapy worldwide. The degradation of 5-Fu by advanced oxidation processes (AOPs) is a poorly addressed topic, and this work brings valuable inputs concerning this matter. Herein, the efficacy of Fenton’s process in the degradation of 5-Fu is explored for the first time; the study of the main variables and its successful application to the treatment of real wastewaters is demonstrated. Moreover, hydrogen peroxide-based and photo-assisted techniques (direct photolysis, photodegradation with H₂O₂ and photo-Fenton) are also investigated for purposes of comparison. Under the best operation conditions obtained (T = 30 °C, [Fe²⁺]₀ = 0.5 mM; [H₂O₂]₀ = 240 mM and pH = 3 for [5-Fu]₀ = 0.38 mM), 5-Fu was completely eliminated after 2 h of Fenton’s reaction and about 50 % of mineralization was reached after 8 h. The best performance was obtained by the photo-Fenton process, with 5-Fu mineralization level as high as 67 %, using an iron dose within the legal limits required for direct water discharge. Toxicity (towards Vibrio fischeri) of the effluents that resulted from the application of the above-mentioned AOPs was also evaluated; it was found that the degradation products generated from the photo-assisted processes are less toxic than the parent compound, putting into evidence the relevance of such technologies for degradation of cytostatics like 5-Fu.

Solidification is a very effective way to alleviate heavy metal impacts to the environment. In this paper, an improved method was adopted herein for the solidification/stabilization (S/S) of sediments with cement-based additives and low content of cement in S/S materials. Sediments in Xiangjiang River, containing high concentrations of Cu, Cd, and Pb, were solidified/stabilized by binders of cement, fly ash, and bentonite. Admixtures such as sodium lignosulfonate, sodium lauryl sulfate, and triethanolamine were used to improve the bonding properties of S/S, which had never been investigated before. Results demonstrated that the addition of concrete admixtures had significant effects on the S/S of sediments. Sequential extraction method indicates that the concentrations of heavy metals changed significantly after solidification and were more stable over time, with the exception of Pb. In addition, SEM images indicated that the main hydrated product was ettringite. Large quantities of calcium silicate hydrates (CSH) formed and filled the solidified sediment in 60 days. The results provide further insights into the transformation of heavy metals during S/S.

Data from the National Health and Nutrition Examination Survey for 1999–2012 were used to evaluate factors that affect observed levels of urine cadmium (UCd) among children aged 6–11 years and nonsmoker adolescents aged 12–19 years. Adjusted UCd levels were found to be statistically significantly higher for female nonsmoker adolescents than male nonsmoker adolescents (p < 0.01). Non-Hispanic white (NHW) participants had statistically significantly lower adjusted levels of UCd (<0.01) than non-Hispanic black (NHB) participants for both children (p < 0.01) and adolescents (p < 0.01). Dietary intake of cadmium was not found to affect the levels of UCd. While unadjusted levels of UCd for nonsmoker adolescents declined (p < 0.01) over 1999–2012 by 28.3%, no statistically significant trend was observed for adjusted levels.

It has been shown previously that, under acidic conditions, 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4-dinitroanisole (DNAN) degrade in the presence of iron/copper bimetal particles; the reactions can be modeled by pseudo-first-order kinetics. This study investigates the reaction mechanisms of the degradation processes under different conditions. Batch studies were conducted using laboratory-prepared solutions and an industrial insensitive munition-laden (IMX) wastewater. The influence of parameters such as initial pH of the solution, copper/iron (Fe-Cu) contact, and solid/liquid ratio were systematically investigated to assess their impact on the reaction kinetics. These parameters were subsequently incorporated into pseudo-first-order decomposition models for NTO and DNAN. The activation energies for the degradation reactions were 27.40 and 30.57 kJ mol⁻¹, respectively. Degradation intermediates and products were identified. A nitro-to-amino pathway, which ultimately may lead to partial mineralization, is postulated. The amino intermediate, aminonitroanisole, was detected during DNAN degradation, but for NTO, aminotiazolone is suggested. Additionally, urea was identified as a degradation product of NTO.

The improper disposal of used frying oil (UFO) presents numerous ecological, environmental and municipal problems. Of great concern is the resultant blockage of municipal drainage systems and water treatment facilities, harm to wildlife when they become coated in it and detriment to aquatic life and ecosystems due to the depletion of the oxygen content in water bodies such as rivers and lakes that have become contaminated. Statistics show that in Trinidad and Tobago, in excess of one million liters of used cooking oil is collected annually from various restaurant chains. This paper investigated the potential of using UFO as a performance enhancing additive for road paving applications utilizing Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB) as a mitigation strategy for improper UFO disposal. Modified blends containing various additions of UFO (2–10% wt) were prepared for the TLA and TPB asphaltic binders. Results demonstrated in terms of stiffness, increasing the dosage of UFO in TLA and TPB base binders resulted in a gradual decrease in stiffness (G* value decreased). In terms of elasticity, increasing the dosage of the UFO additive in TLA resulted in a general decrease in the elasticity of the blends indicated by an increase in phase angle or phase lag (δ). Increasing dosages of the UFO additive in TPB resulted in a significant decrease in δ where the most elastic blend was at the 6% UFO level. TLA and UFO-TLA modified blends exhibited significantly lower values of δ and higher values of G* confirming the superiority of the TLA material. Incorporation of the UFO in the blends led to a decrease in the rutting resistance and increase in the fatigue cracking resistance (decrease in G*/sinδ and G*sinδ, respectively). This study highlighted the potential for the reuse of UFO as an asphalt modifier capable of producing customized UFO modified asphaltic blends for special applications and confirms its feasibility as an environmentally attractive means of reusing the waste/hazardous UFO material locally.

Characterization of beach debris is crucial to assess the strategy to answer questions such as recycling. With the aim to assess its use in a recycling scheme, in this note, we carried out a physical and chemical characterization of plastic litter from a pilot beach in Central Italy, using the FT-IR spectroscopy and thermoanalysis. Fourteen polymers, having mainly thermoplastic origin, were identified; among them, the most represented are polyethylene (41.7%) and polypropylene (36.9%). Chemical and mechanical degradation were clearly observed by an IR spectrum. The thermogravimetric analysis curve of the plastic blend shows the melting point at 120–140 °C, and degradation occurs almost totally in a one-step process within 300–500 °C. The high heating value of the plastic debris is 43.9 MJ kg⁻¹. Polymer blends obtained by beach debris show mechanical properties similar to the virgin high-density polyethylene polymer. Following the beach plastic debris characterization, a recycling scheme was suggested.