Cumulative Risk Assessment of Exposure to Heavy Metals through Aquatic Products in China

Objective This study aimed to assess the risk of cumulative exposure to Pb,Cd,Hg,and iAs through aquatic products consumed by Chinese people.Methods Heavy metal concentration data were obtained from the national food contamination monitoring program during 2013–2017.Consumption data were derived from the China National Food Consumption Survey in 2014 and the relative potency factor(RPF)method was used to estimate cumulative exposure for neurotoxicity and nephrotoxicity.Results The results demonstrated that the cumulative exposure based on neurotoxicity was below the lower confidence limit on benchmark doses of lead(BMDL01)for nephrotoxicity and the cumulative exposures were all lower than the provisional tolerable monthly intake(PTMI)of Cd.However,the margin of exposure values(MOEs)of the cumulative exposures for neurotoxicity in the 2–6 year-old group was close to 1 and the cumulative exposure level for nephrotoxicity accounted for 90.21%of the PTMI.Conclusion The cumulative exposures of the 2–6 year-old group to the four heavy metals did not reach(but came close to)the corresponding safety threshold for both neurotoxicity and nephrotoxicity.Given that there are still other food sources of these four heavy metals,it is necessary to more closely study their cumulative health effects.

In situ growth of polydopamine on surface of covalent organic frameworks under the catalysis of acid phosphatase for dopamine detection

Dopamine(DA)is easy to be oxidized and polymerizes to form polydopamine(pDA)in alkaline conditions,while the synthesis is usually time-consuming(48 h).Herein,the polymerization of DA is completed with 4 h under the catalysis of acid phosphatase(ACP).The high efficiency makes the detection of DA feasibility based on the self-polymerization of DA.In this assay,pDA is grown in situ on the surface of covalent organic frameworks(COFs),and then the fluorescence of COFs is quenched significantly.The linear range of DA is achieved from 0.5-50μmol/L with a detection limit of 0.16μmol/L.The detection of DA is not interfered with uric acid,ascorbic acid,and some phenolic compounds,because these substances cannot polymerize in the presence of ACP.Moreover,benefiting from the good sensitivity and selectivity,DA has been successfully determined by this strategy in human urine samples with satisfactory recoveries.