pH, ionic strength and dissolved organic matter alter aggregation of fullerene C60 nanoparticles suspensions in wastewater

The rapid increase in the production and use of fullerene C60 nanoparticles raise concerns about environmental risks and human health. Wastewater treatment plants are key barriers to their discharge into the environment. The aggregation behavior of aqueous suspensions of C60 nanoparticles (nC60) could affect their transport, bioavailability, and removal during wastewater treatment. We tested the aggregation of nC60 in wastewater at different values of pH, ionic strength, and dissolved organic matter (DOM). The nC60 remained relatively stable in filtered wastewater under environmentally relevant conditions up to 24h. But at pH 3 or at high ionic strength (\u3e100mM NaCl), the aggregate size increased greatly, reaching micrometer scale after only 1h. However, the aggregation behavior varied among wastewater samples even at values of similar zeta potential, compared with that in filtered secondary effluent and aeration tank liquor, that in filtered primary effluent was obviously inhibited. This inhibition could be attributed to the steric stabilization due to the adsorption of DOM on nC60 aggregate in addition to electrostatic stabilization. The aggregation results also suggest that membrane filtration could be improved by adjustments to pH

pH, ionic strength and dissolved organic matter alter aggregation of fullerene C60 nanoparticles suspensions in wastewater

The rapid increase in the production and use of fullerene C60 nanoparticles raise concerns about environmental risks and human health. Wastewater treatment plants are key barriers to their discharge into the environment. The aggregation behavior of aqueous suspensions of C60 nanoparticles (nC60) could affect their transport, bioavailability, and removal during wastewater treatment. We tested the aggregation of nC60 in wastewater at different values of pH, ionic strength, and dissolved organic matter (DOM). The nC60 remained relatively stable in filtered wastewater under environmentally relevant conditions up to 24h. But at pH 3 or at high ionic strength (\u3e100mM NaCl), the aggregate size increased greatly, reaching micrometer scale after only 1h. However, the aggregation behavior varied among wastewater samples even at values of similar zeta potential, compared with that in filtered secondary effluent and aeration tank liquor, that in filtered primary effluent was obviously inhibited. This inhibition could be attributed to the steric stabilization due to the adsorption of DOM on nC60 aggregate in addition to electrostatic stabilization. The aggregation results also suggest that membrane filtration could be improved by adjustments to pH

Rapid determination of free and conjugated estrogen in different water matrices by liquid chromatography-tandem mass spectrometry

This article describes the development of a short pre-treatment method that allows the simultaneous analysis of free estrogens (estrone, 17β-estradiol, estriol and 17-ethynylestradiol) and their sulphate and glucuronide conjugated forms. For a range of matrices, from sewage effluent to river water, the developed methodology based on solid phase extraction and fractionation technique with ultra-performance liquid chromatography system showed effective separation of the targeted estrogens. The detection limits of this method ranged from 0.2 to 0.8 ng L–1 for river water. The recoveries for river water and sewage effluent varied from 63 to 127%. The problems of matrix effects and ion suppression, or enhancement, were allowed quantitatively for in the analysis using standard addition. The developed method was used successfully to detect estrogens and their conjugates in both raw and treated wastewater, and river water at a location in Japan. High concentrations of the free estrogens estrone, 17β-estradiol and estriol were found in the influent (22.6, 77.2, 64.6 ng L–1 respectively) but only E1 was still present at a high concentration in the effluent which was reflected in the downstream river concentration. Estrone-3-sulphate was detected up to 18.0 ng L–1 in influent water sample and 1.1 ng L–1 in downstream water. For the sulphate conjugates, removal efficiencies varied from 35 to 88%.. Glucuronide conjugates were detected only once in the sewage influent

The arrival and discharge of conjugated estrogens from a range of different sewage treatment plants in the UK

The occurrence of free and conjugated estrogens were examined in a survey of eleven sewage treatment plants (STPs) and their discharge water in the United Kingdom using grab sampling. The STPs included trickling filter with and without tertiary treatment, and activated sludge with tertiary treatment. For three activated sludge plants both influent and effluent samples were compared. For a further 8 STPs only the effluent was examined. The estrone-3-sulphate, estradiol-3-sulphate and estriol-3-sulphate concentrations (up to 20 ng/L) were typically fivefold that of their respective free estrogen concentrations in the effluents. This represents a substantial additional ‘potential’ estrogen load arriving in the receiving waters. Estrone-3-glucuronide was found at 9.3 ng/L, estradiol-3-glucuronide at 7.0 ng/L, and estriol-3-glucuronide at 32.2 ng/L in sewage influent. Except on one occasion, no glucuronide conjugates could be found in the effluent.. The results suggest in most cases glucuronide conjugates will be completely transformed in sewage treatment whilst sulphate conjugates will only be partially removed

Biological Monitoring of human exposure to neonicotinoids using urine samples, and neonicotinoid excretion kinetics

[Background] Neonicotinoids, which are novel pesticides, have entered into usage around the world because they are selectively toxic to arthropods and relatively non-Toxic to vertebrates. It has been suggested that several neonicotinoids cause neurodevelopmental toxicity in mammals. The aim was to establish the relationship between oral intake and urinary excretion of neonicotinoids by humans to facilitate biological monitoring, and to estimate dietary neonicotinoid intakes by Japanese adults. [Methodology/Principal Findings] Deuterium-labeled neonicotinoid (acetamiprid, clothianidin, dinotefuran, and imidacloprid) microdoses were orally ingested by nine healthy adults, and 24 h pooled urine samples were collected for 4 consecutive days after dosing. The excretion kinetics were modeled using one- and two-compartment models, then validated in a non-deuterium-labeled neonicotinoid microdose study involving 12 healthy adults. Increased urinary concentrations of labeled neonicotinoids were observed after dosing. Clothianidin was recovered unchanged within 3 days, and most dinotefuran was recovered unchanged within 1 day. Around 10% of the imidacloprid dose was excreted unchanged. Most of the acetamiprid was metabolized to desmethyl-Acetamiprid. Spot urine samples from 373 Japanese adults were analyzed for neonicotinoids, and daily intakes were estimated. The estimated average daily intake of these neonicotinoids was 0.53-3.66 μg/day. The highest intake of any of the neonicotinoids in the study population was 64.5 μg/day for dinotefuran, and this was <1% of the acceptable daily intake

Amounts of the labeled compounds found to be excreted in the urine (μg d⁻¹) in a 24 h period after a single dose was ingested (circles) and the model curves (red lines).

<p>The green bars are the means and the lower and upper blue whiskers are the standard deviations.</p

Deuterium-labeled neonicotinoids used in the dosing study.

<p>Deuterium-labeled neonicotinoids used in the dosing study.</p