No abstract

The occurrence and fate of 5 cyclic (D3 to D7) and 12 linear (L3 to L14) siloxanes were investigated in raw and treated wastewater (both particulate and dissolved phases) as well as in sludge from a wastewater treatment plant (WWTP) in Athens, Greece. Cyclic and linear siloxanes (except for L3) were detected in all influent wastewater and sludge samples at mean concentrations of (sum of 17 siloxanes) 20 μg L(-1) and 75 mg kg(-1), respectively. The predominant compounds in wastewater were L11 (24% of the total siloxane concentration), L10 (16%), and D5 (13%), and in sludge were D5 (20%) and L10 (15%). The distribution of siloxanes between particulate and dissolved phases in influents differed significantly for linear and cyclic siloxanes. Linear siloxanes showed higher solid-liquid distribution coefficients (log K(d)) than did cyclic compounds. For 10 of the 16 compounds detected in influents, the removal efficiency was higher than 80%. Sorption to sludge and biodegradation and/or volatilization losses are important factors that affect the fate of siloxanes in WWTPs. The mean total mass of siloxanes that enter into the WWTP via influent was 15.1 kg per day(-1), and the mean total mass released into the environment via effluent was 2.67 kg per day(-1).

No abstract

Synthetic phenolic antioxidants (SPAs), including 2,6-di-tert-butyl-4-hydroxytoluene (BHT), are extensively used in food, cosmetic and plastic industries. Nevertheless, limited information is available on human exposures, other than the dietary sources, to SPAs. In this study, occurrence of 9 SPAs and their metabolites/degradation products was determined in 339 indoor dust collected from 12 countries. BHT was found in 99.5% of indoor dust samples from homes and microenvironments at concentrations that ranged from < LOQ to 118 μg/g and 0.10 to 3460 μg/g, respectively. This is the first study to measure BHT metabolites in house dust (0.01-35.1 μg/g) and their concentrations accounted for 9.2-58% of the sum concentrations (∑SPAs). 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO), 2,6-di-tert-butyl-4-(hydroxymethyl)phenol (BHT-OH), 2,6-di-tert-butyl-1,4-benzoquinone (BHT-Q) were the major derivatives of BHT found in dust samples. The concentrations of gallic acid esters (gallates) in dust from homes and microenvironments ranged from < LOQ to 18.2 and < LOQ to 684 μg/g, respectively. The concentrations and profiles of SPAs varied among countries and microenvironments. Significantly elevated concentrations of SPAs were found in dust from an e-waste workshop (1530 μg/g). The estimated daily intake (EDI) of BHT via house dust ingestion ranged from 0.40 to 222 ng/kg/d (95th percentile).

No abstract

Benzotriazole (BTR) and benzothiazole (BTH) derivatives are high-production-volume chemicals that are mainly used as corrosion inhibitors, and are widely distributed in the environment. BTR derivatives are found in plastics, dishwasher detergents, dry cleaning equipment, and de-icing/anti-icing fluids. BTH derivatives are found in rubber materials, herbicides, slimicides, algicides, fungicides, photosensitizers, azo dyes, drugs, de-icing/anti-icing fluids, and food flavors. However, exposure of humans to BTRs and BTHs is still not known. In this study, six BTRs (1H-benzotriazole, 1-hydroxy-benzotriazole, 4- and 5-hydroxy-benzotriazole [mixture of two isomers], tolyltriazole, xylyltriazole [or 5,6-dimethyl-1H-benzotriazole], and 5-chloro-benzotriazole) and six BTHs (benzothiazole, 2-morpholin-4-yl-benzothiazole, 2-hydroxy-benzothiazole, 2-methylthio-benzothiazole, 2-amino-benzothiazole, and 2-thiocyanomethylthio-benzothiazole) were determined in human urine collected from general populations in seven countries (the U.S., Greece, Vietnam, Korea, Japan, China, and India). The median urinary concentration of the sum of five BTRs (Σ5BTRs; 4- and 5-hydroxy-benzotriazole were not included) ranged from 0.2 (Korea) to 2.8 (India)ng/mL among the countries studied, with the highest concentration of 24.5ng/mL found in a sample from China. Xylyltriazole was found more frequently in urine from all five Asian countries than in urine from the U.S. and Greece. The median concentration of the sum of the six BTHs (Σ6BTHs) ranged from 3.6 (U.S.) to 10.9 (Japan)ng/mL among the countries studied, with a maximum detection rate of 100% in urine samples from Vietnam; BTH was the predominant derivative, accounting for, on average, 43% of the Σ6BTH concentration. Based on the concentrations and detection rates of several BTR and BTH derivatives in urine, possible metabolic transformation pathways of these compounds were presented and human exposure doses calculated. The estimated daily intake doses of BTRs and BTHs were on the order of a few to few tens of micrograms per day.

Background Exposure to bisphenols and phthalates in pregnancy may lead to adverse health effects in women themselves and their offspring. Objective To describe first trimester bisphenol and phthalate urine concentrations, including bisphenol and phthalate replacements, and determine nutritional, socio-demographic and lifestyle related determinants. Methods In a population-based prospective cohort of 1396 mothers, we measured first trimester bisphenol, phthalate and creatinine urine concentrations (samples collected in 2004–2005, median gestational age 12.9 weeks [inter-quartile range (IQR) 12.1–14.4]). We examined associations of potential determinants with log-transformed bisphenol and phthalate concentrations. Outcomes were back-transformed. Nutritional analyses were performed in a subgroup of 642 Dutch participants only, as the Food Frequency Questionnaire was aimed at Dutch food patterns. Results Bisphenol A, bisphenol S, and bisphenol F were detected in 79.2%, 67.8% and 40.2% of the population, respectively. Mono-n-butylphthalate, mono-(2-ethyl-5-hydroxyhexyl)phthalate and monobenzylphthalate were detected in > 90% of the population. Nutritional intake was not associated with bisphenol and phthalate concentrations after correction for multiple testing was applied. Obesity was associated with higher high-molecular-weight phthalate concentrations and the lack of folic acid supplement use with higher di-n-octylphthalate concentrations (respective mean differences were 46.73 nmol/l [95% CI 14.56–93.72] and 1.03 nmol/l [0.31–2.06]). Conclusion Bisphenol S and F exposure was highly prevalent in pregnant women in the Netherlands as early as 2004–5. Although associations of dietary and other key factors with bisphenol and phthalate concentrations were limited, adverse lifestyle factors including obesity and the lack of folic acid supplement use seem to be associated with higher phthalate concentrations in pregnant women. The major limitation was the availability of only one urine sample per participant. However, since phthalates are reported to be quite stable over time, results concerning determinants of phthalate concentrations are expected to be robust.

No abstract