This study evaluated the toxicity of herbicide atrazine, along with its bioaccumulation and biodegradation in the green microalga Chlamydomonas mexicana. At low concentration (10 μg L⁻¹), atrazine had no profound effect on the microalga, while higher concentrations (25, 50, and 100 μg L⁻¹) imposed toxicity, leading to inhibition of cell growth and chlorophyll a accumulation by 22 %, 33 %, and 36 %, and 13 %, 24 %, and 27 %, respectively. Atrazine 96-h EC50 for C. mexicana was estimated to be 33 μg L⁻¹. Microalga showed a capability to accumulate atrazine in the cell and to biodegrade the cell-accumulated atrazine resulting in 14–36 % atrazine degradation at 10–100 μg L⁻¹. Increasing atrazine concentration decreased the total fatty acids (from 102 to 75 mg g⁻¹) and increased the unsaturated fatty acid content in the microalga. Carbohydrate content increased gradually with the increase in atrazine concentration up to 15 %. This study shows that C. mexicana has the capability to degrade atrazine and can be employed for the remediation of atrazine-contaminated streams.

We report, for the first time, the biotransformation of potential pollutants bearing the pentafluorosulfanyl (SF₅-) functional group in a fungus and bacteria. Cunninghamella elegans transformed p-methoxy phenyl SF₅via demethylation; Pseudomonas knackmussii and P. pseudoalcaligenes KF707 transformed amino-, hydroxyamino- and diamino- substituted phenyl SF₅, forming the N-acetylated derivatives as the main product. Cell-free extract of Streptomyces griseus transformed 4-amino-3-hydroxy-phenyl SF₅to the N-acetylated derivative in the presence of acetyl CoA, confirming that an N-acetyltransferase is responsible for the bacterial biotransformations. Approximately 25 % of drugs and 30 % of agrochemicals contain fluorine, and the trifluoromethyl group is a prominent feature of many of these since it improves lipophilicity and stability. The pentafluorosulfanyl substituent is seen as an improvement on the trifluoromethyl group and research efforts are underway to develop synthetic methods to incorporate this moiety into biologically active compounds. It is important to determine the potential environmental impact of these compounds, including the potential biotransformation reactions that may occur when they are exposed to microorganisms.

Phthalate acid esters are becoming an important class of pollutants in wastewaters. This study addresses the kinetics of removal of dimethyl phthalate (DMP) using the anion exchange resin D201-OH from an aqueous solution. The effects of various factors on the removal rate and efficiency were investigated. An overall initial removal rate (OIRR) law and a pseudo first-order kinetic (PFOK) model were also developed. The internal diffusion of DMP within the resin phase of D201-OH is the rate-controlling step. Optimization of the particle size and pore structure of the resin D201-OH, the DMP concentration, and the reaction temperature can improve the DMP removal rate. The hydrolysis reaction of DMP catalyzed by D201-OH indicates an overall reaction order of 1.76, a value that is between the first order and the second order. The apparent activation energy of the reaction is 34.6 kJ/mol, which is below the homogeneous alkaline hydrolysis activation energy of 44.3 kJ/mol. The OIRR law can quantify the initial removal rate under different conditions. The results also show that the theoretical DMP removal efficiency predicted by the PFOK model agrees well with the experimentally determined values. Our research provides valuable insights into the primary parameters influencing the kinetic process, which enables a focused improvement in the removal or hydrolysis rate for similar processes.

Within the French observatories network SOERE “URBIS,” databases of continuous turbidity measurements accumulating hundreds of events and many dry weather days are available for two sites with different features (Clichy in Paris and Ecully in Lyon). These measurements, converted into total suspended solids (TSS) concentration using TSS–turbidity relationships and combined with a model of runoff event mean concentration, enable the assessment of the contribution of sewer deposits to wet weather TSS loads observed at the outlet of the two watersheds. Results show that the contribution of sewer deposits to wet weather suspended solid’s discharges is important but variable (between 20 and 80 % of the mass at the outlet depending on the event), including a site allegedly free of (coarse) sewer deposits. The uncertainties associated to these results are assessed too.

Polychlorinated biphenyls (PCBs) and DDT are widespread environmental persistent organic pollutants that have various adverse effects on reproduction, development and endocrine function. In order to elucidate effects of PCBs and DDT on thyroid hormone homeostasis, Sprague–Dawley rats were dosed with PCB153 and p,p′-DDE intraperitoneally (ip) for five consecutive days and sacrificed within 24 h after the last dose. Results indicated that after combined exposure to PCB153 and p,p′-DDE, total thyroxine , free thyroxine, total triiodothyronine, and thyroid-stimulating hormone in serum were decreased, whereas free triiodothyronine and thyrotropin-releasing hormone were not affected. Thyroglobulin and transthyretin levels in serum were significantly reduced. mRNA expression of deiodinases 2 (D2) was also suppressed, while D1 and D3 levels were not significantly influenced after combined exposure. PCB153 and p,p′-DDE induced hepatic enzymes, UDPGTs, CYP1A1, CYP2B1, and CYP3A1 mRNA expressions being significantly elevated. Moreover, TRα1, TRβ1, and TRHr expressions in the hypothalamus displayed increasing trends after combined exposure to PCB153 and p,p′-DDE. Taken together, observed results indicate that PCB153 and p,p′-DDE could disorder thyroid hormone homeostasis via thyroglobulin, deiodinase 2, transthyretin, hepatic enzymes, and hormone receptors.

The 14th European Association of Chemical and Molecular Sciences (EuCheMS) International Conference on Chemistry and the Environment (ICCE 2013) took place on 25–28 June 2013 at the IEC and the WTC in Barcelona, Spain. The ICCE is a well-established biannual conference organized by the Division of Chemistry and the EuCheMS.

Tibetan Plateau is the world’s highest plateau, which provides a unique location for the investigation of global fractionation of organochlorine pesticides (OCPs). In this study, deposition and regional distribution of HCHs and p,p′-DDX in the western and southern Tibetan Plateau were investigated by the records from a sediment core of Lake Zige Tangco and 24 surface soils. Concentration of ΣHCHs in the surface soils of the western Tibetan Plateau was much higher than that of the southern part. Maximum fluxes of α-, β-, and δ-HCH in the sediment core were 9.0, 222, and 21 pg cm⁻² year⁻¹, respectively, which appeared in the mid-1960s. Significant correlations were observed between concentrations of α- and β-HCH in both the surface soils and the sediment core. Concentrations of both α- and β-HCH increased with the inverse of the average annual temperature of these sites. γ-HCH became the dominant isomer of HCHs after the late 1970s, and reached the maximum flux of 160 pg cm⁻² year⁻¹in the early 1990s. There were no significant correlations between concentrations of γ-HCH and the other isomers in both the surface soils and the sediment core. The results suggested that there was input of Lindane at scattered sites in this area. In contrast to ΣHCHs, concentration of Σp,p′-DDX in the surface soils of the southern part was much higher than that of the western part. Maximum flux of Σp,p′-DDX was 44 pg cm⁻² year⁻¹, which appeared in the mid-1960s. Local emission of p,p′-DDT was found at scattered sites. This study provides novel data and knowledge for the OCPs in the western and southern Tibetan Plateau, which will help understand the global fractionation of OCPs in remote alpine regions.

Biologically based wastewater treatment systems are considered a sustainable, cost-effective alternative to conventional wastewater treatment systems. These systems have been used and studied for the treatment of urban sewage from small communities, and recently, it has been reported that they can also effectively remove emerging organic contaminants (EOCs). EOCs are a new group of unregulated contaminants which include pharmaceutical and personal care products, some pesticides, veterinary products, and industrial compounds among others that are thought to have long-term adverse effects on human health and ecosystems. This review is focused on reporting the ability of biologically based wastewater treatment systems to remove EOCs and the main elimination mechanisms and degradation processes (i.e., biodegradation, photodegradation, phytoremediation, and sorption) taking place in constructed wetlands, ponds, and Daphnia and fungal reactors.

Due to activities involving nuclear energy research during the latter half of the 1900s, environmental contamination in the form of elevated cesium-137 levels was observed within the Brookhaven National Laboratory, a US Department of Energy facility. Between the years 2000 and 2005, the laboratory carried out a major soil cleanup effort to remove cesium-137 from contaminated sites. In this study, we examine the effectiveness of the cleanup effort by comparing the levels of cesium-137 in the meat of white-tailed deer found within and around the laboratory. Results suggest that the cleanup was effective, with mean concentration of cesium-137 in the meat from within the laboratory decreasing from 2.04 Bq/g prior to 1.22 Bq/g after cleanup. At the current level, the consumption of deer would not pose any human health hazard. Nevertheless, statistically higher levels of cesium-137 were detected in the deer within the laboratory as opposed to levels found in deer 1 mi beyond the laboratory site.