How to select relevant metabolites based on available data for parent molecules: Case of neonicotinoids, carbamates, phenylpyrazoles and organophosphorus compounds in French water resources.

The presence of pesticide in water resources is a topical issue in France as in many other countries. Resources can be contaminated by current-used pesticides and their metabolites but also by molecules banned 50 years ago. The number of reported studies on the impact of these substances on human health and environment increases every day. Currently, pesticides and their relevant degradation products are subjected to the European regulation for water intended for human consumption. It sets an individual quality limit of 0.1 µg/L, and another of 0.5 µg/L for the sum of their concentrations. The constant improvement of analytical methods allows laboratories to detect pesticides, at lower and lower concentrations but also more and more metabolites. However, regulation does not provide a national indicative metabolites list to be monitored. Each regional health agency offers their own list based on local agricultural practices and quantities of pesticides sold. This article reports a prioritization method allowing to identify new metabolites to be monitored in water resources, along drinking water treatment plants and in treated water; it describes its application in France in order to anticipate possible non-compliance with raw water and treated water and to provide solutions upstream of changes in sanitary control. This methodology has been developed to rank pesticides and to select the corresponding metabolites by combining three main criteria: use (sale and type of use), toxicity, and environmental fate (based on physical and chemical properties). Prioritization method was applied to four families of pesticides: carbamates, organophosphorus compounds, phenylpyrazoles and neonicotinoids, for which there is a real lack of knowledge as regards the occurrence of their metabolites in metropolitan France. 146 pesticides have been prioritized. The first 50 molecules were considered allowing the identification of 72 metabolites to be monitored in water resources and along drinking water treatment plants.

Analysis of endocrine activity in drinking water, surface water and treated wastewater from six countries.

The aquatic environment can contain numerous micropollutants and there are concerns about endocrine activity in environmental waters and the potential impacts on human and ecosystem health. In this study a complementary chemical analysis and in vitro bioassay approach was applied to evaluate endocrine activity in treated wastewater, surface water and drinking water samples from six countries (Germany, Australia, France, South Africa, the Netherlands and Spain). The bioassay test battery included assays indicative of seven endocrine pathways, while 58 different chemicals, including pesticides, pharmaceuticals and industrial compounds, were analysed by targeted chemical analysis. Endocrine activity was below the limit of quantification for most water samples, with only two of six treated wastewater samples and two of six surface water samples exhibiting estrogenic, glucocorticoid, progestagenic and/or anti-mineralocorticoid activity above the limit of quantification. Based on available effect-based trigger values (EBT) for estrogenic and glucocorticoid activity, some of the wastewater and surface water samples were found to exceed the EBT, suggesting these environmental waters may pose a potential risk to ecosystem health. In contrast, the lack of bioassay activity and low detected chemical concentrations in the drinking water samples do not suggest a risk to human endocrine health, with all samples below the relevant EBTs.

Reduction of endocrine disruptor emissions in the environment: the benefit of wastewater treatment.

The occurrence and fate of four estrogens and five alkylphenolic compounds were studied in thirteen plants with various treatment processes, sizes and countries. Complete load mass balance, including water and sludge phases, has shown a high reduction of the total load of hormones, around 90%. The removal of alkylphenols was more variable, due to the degradation of nonylphenol (NP) precursors - alkylphenol polyethoxylates (APnEO) - during the treatment, resulting in significant production of shorter and toxic alkylphenols (NP and short polyethoxylates) that concentrate in the sludges. Under anaerobic conditions, such as anaerobic digestion process, the load of NP was in most cases observed to increase. When considering the environmental impact, the high reduction of endocrine disrupting compounds (EDC) concentrations between raw wastewater and effluent enables to satisfy the requirements of the Water Framework Directive for NP except in very critical situations where the dilution factor of the effluent in the river would be lower than 7. For sludges, the pending European Directive on spreading of sludge on land would be complied with in all cases.

Fate of sex hormones in two pilot-scale municipal wastewater treatment plants: conventional treatment.

The fate of seven sex hormones (estrone (E1), estradiol (E2), estriol (E3), ethinylestradiol (EE2), testosterone, androstenedione, and progesterone) was determined in two pilot-scale wastewater treatment plants operated under conventional loading conditions. The levels of hormones in both the liquid and the solid matrixes of the plants were determined. Each of the two 20-l/h pilot-scale plants consisted of a primary clarifier followed by a three-stage aeration tank and a final clarifier. The primary sludge and the waste activated sludge (WAS) were digested anaerobically in one pilot plant and aerobically in the other. The pilot plants were fed a complex synthetic wastewater spiked with the hormones. Levels of testosterone, androstenedione and progesterone were close to method detection limit (MDL) concentrations in the final and digester effluents (both liquid and solid phases) and were considered as completely removed. Average mass flux removals from the liquid streams (plant influent minus secondary clarifier effluent) for the natural estrogens were 82% for E1, 99% for E2, and 89% for (E1+E2). An average overall removal of only 42% was achieved for EE2. These values reflect removals averaged for the two pilot plants.

Determination of sex hormones and nonylphenol ethoxylates in the aqueous matrixes of two pilot-scale municipal wastewater treatment plants.

Two analytical methods were developed and refined for the detection and quantitation of two groups of endocrine-disrupting chemicals (EDCs) in the liquid matrixes of two pilot-scale municipal wastewater treatment plants. The targeted compounds are seven sex hormones (estradiol, ethinylestradiol, estrone, estriol, testosterone, progesterone, and androstenedione), a group of nonionic surfactants (nonylphenol polyethoxylates), and their biodegradation byproducts nonylphenol and nonylphenol ethoxylates with one, two, and three ethoxylates. Solid phase extraction using C-18 for steroids and graphitized carbon black for the surfactants were used for extraction. HPLC-DAD and GC/MS were used for quantification. Each of the two 20 L/h pilot-scale plants consists of a primary settling tank followed by a three-stage aeration tank and final clarification. The primary and the waste-activated sludge are digested anaerobically in one plant and aerobically in the other. The pilot plants are fed with a complex synthetic wastewater spiked with the EDCs. Once steady state was reached, liquid samples were collected from four sampling points to obtain the profile for all EDCs along the treatment system. Complete removal from the aqueous phase was obtained for testosterone, androstenedione, and progesterone. Removals for nonylphenol polyethoxylates, estradiol, estrone, and ethinylestradiol from the aqueous phase exceeded 96%, 94%, 52%, and 50%, respectively. Levels of E3 in the liquid phase were low, and no clear conclusions could be drawn concerning its removal.

Toxic by-products from the combustion of Kraft lignin.

Lignin samples, sub-product in the Kraft process of cellulose from eucalyptus wood, were burnt in a laboratory scale furnace at different residence temperatures and with distinct fuel-rich atmospheres. The yields of CO, CO(2), eight light hydrocarbons (methane, ethylene, ethane, propylene, acetylene, butane, etc.) and 60 semi-volatile+volatile compounds (benzene, toluene, ethylbenzene, styrene, indene, naphthalene, dibenzofuran, phenanthrene, chrysene, etc.) were determined, with nominal reactor temperatures between 800 and 1100 degrees C and residence times of the volatiles evolved and formed between 4 and 7 s. The collection of the gases and volatiles evolved was carried out with a Tedlar bag and by XAD-4 resin respectively, comparing the data obtained in both cases. The emission factor (mg/kg) of the CO was between 2500 and 90000, and under the poor-oxygen atmosphere, the emission factors of many by-toxic products were greater than 100 mg/kg. A pyrolysis run was also performed, obtaining emission factors between 30 and 3000 mg/kg, facilitating its identification. The behaviour of different compounds in the combustion runs was discussed considering three groups in accordance with their stability vs. oxygen, and two groups vs. temperature.