[Exposure Levels, Sources, and Health Risks of Heavy Metal Components of PM2.5 in Housewives in Rural Shanghai].

To investigate exposure characteristics and potential health risk of PM2.5-bound heavy metals in housewives in rural areas, 265 personal exposure samples from 143 subjects were collected in the Songjiang district, Shanghai from February 2017 to June 2018. Mass concentrations of 13 elements in PM2.5 were determined by energy-dispersive X-ray fluorescence spectrometry (ED-XRF). The sources of heavy metal components in PM2.5 were analyzed using positive matrix factorization (PMF). The inhalation health risks of exposure to Ni, V, Cr, Mn, As, and Pb were analyzed using the US EPA health risk assessment model. The results showed that the average concentration of personal exposure to PM2.5 was 40.61 µg·m-3 in housewives, which was higher than the concentration at peripheral monitoring stations. The carcinogenic risks of Cr(Ⅵ)and As exceeded the acceptable risk level (10-6). The non-carcinogenic risks of V, Cr(Ⅵ), Mn, Ni, and As were all below the safety threshold, while the total non-carcinogenic risks of these five elements were higher than the safety threshold (>1). The results of PMF indicated that resuspended dust and indoor dust(43.8%), the metallurgy industry(34.6%), coal combustion(14.5%), and fossil-fuel combustion(7.2%)were the major sources of ten elements (Al, Ti, V, Cr, Mn, Fe, Ni, Zn, As, and Pb) in PM2.5. Based on the results of health risk assessment of pollution sources, control measures on the metallurgy industry and fossil-fuel combustion should be further strengthened.

Degradation of azo dye Acid black 1 using low concentration iron of Fenton process facilitated by ultrasonic irradiation.

A combination of ultrasonic and low concentration iron (<3 mgL(-1)) of Fenton process (US/Fenton) has been used to treat wastewater containing Acid black 1 (AB1). The results show that the oxidation power of low concentration iron of Fenton could be significantly enhanced by ultrasonic irradiation. The degradation of AB1 in aqueous solution by US/Fenton can receive better results compared with either Fenton oxidation or ultrasonic alone. Many operational parameters, such as ultrasonic power density, the pH value, the Fe(2+) dosage, the H(2)O(2) dosage, AB1 concentration and the temperature, affecting the degradation efficiency were investigated. Also, the effects of various inorganic anions (such as Cl(-), NO(3)(-), CO(3)(2-), etc.) on the oxidation efficiency of US/Fenton were studied. Under the given test conditions, 98.83% degradation efficiency was achieved after 30 min reaction by US/Fenton. The effect of various inorganic anions was in the following decreasing order: SO(3)(2-)>CH(3)COO(-)>Cl(-)>CO(3)(2-)>HCO(3)(-)>SO(4)(2-)>NO(3)(-). The results show that the US/Fenton can be an effective technology for the treatment of organic dyes in wastewater.