RESUMEN
Chlorinated paraffins (CPs) are industrial chemicals that have potential adverse effects in the environment and on human health. This study investigated CPs in apiary environment, honeybees, and bee products from two rural areas of Beijing, China. The median concentrations of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) were 22 and 1.6 ng/m3 in the ambient air, 1350 and 708 ng/g dry mass (dw) in bees, 1050 and 427 ng/g dw in flowers, 37 and 54 ng/g in honey, 78 and 53 ng/g dw in bee pollen, 36 and 30 ng/g dw in soil, and 293 and 319 ng/g dw in bee wax. C10Cl6-7 and C14Cl7-8 dominated SCCPs and MCCPs in these samples, respectively. The concentrations and distributions of CPs in samples from apiaries located in the two regions varied. Long-range transportation of air masses was identified as an important source of CPs in apiaries. A close relationship between CPs in bees and the apiary environment indicated that bees could act as bioindicators for CP contamination in the environment. A human health risk assessment found that there were low risks for adults and children exposed to CPs through consumption of honey and pollen from the studied regions.
Asunto(s)
Hidrocarburos Clorados , Parafina , Niño , Abejas , Humanos , Animales , Parafina/análisis , Monitoreo del Ambiente , Hidrocarburos Clorados/análisis , China , BeijingRESUMEN
Herein, novel magnetic nickel incorporated carbon nanofibers (Ni@CNF) were successfully synthesized via electrostatic spinning method for sulfadiazine (SDZ) adsorption. We combined computational and experimental tools to clarify the distinct nature of SDZ on Ni@CNF. Extensive computations and characterizations of SDZ-Ni adsorption complexes evidenced that Ni atoms were indispensable for SDZ adsorption and increasing the number of Ni atoms in Ni@CNF significantly improved SDZ adsorption due to the lower adsorption energy (Ead). As we surmised, the adsorption capacity of Ni@CNF enhanced gradually with increasing the mass ratio of Ni in the composite. The as-prepared 9%Ni@CNF achieved removal efficiency of 98.9% for SDZ (2.5 mg/L) in 25 min, while the pure CNF hardly removed any SDZ under the identical conditions. The experimental data was better fitted by the Langmuir model with the maximum monolayer adsorption capacity of 103.21 mg/g at 318 K. Besides, the 9%Ni@CNF exhibited great applicability to various organic contaminants, and excellent stability and reusability over five consecutive cycles. Overall, for the first time, we provide the evidence that Ni atoms in the Ni@CNF plays a crucial role in SDZ adsorption, which can guide us for constructing nickle incorporated adsorbents with impressive adsorption capacity in environmental remediation.