A nationwide investigation of trace elements in rice and wheat flour in China: Levels, spatial distributions and implications for human exposure.

Rises in trace element contents in rice and wheat flour, which are staple foods for almost all the Chinese population, associated with rapid economic development have raised major concerns. This study aimed to assess trace element concentrations in these foods nationwide in China and associated human exposure risks. For these purposes, nine trace elements were measured in 260 rice samples and 181 wheat flour samples with 17 and 12 widely scattered geographical origins in China, respectively. Mean concentrations (mg kg-1) of the trace elements declined in the following orders: Zn > Cu > Ni > Pb > As > Cr > Cd > Se > Co in rice, and Zn > Cu > Ni > Se > Pb > Cr > Cd > As > Co in wheat flour. Significant regional differences in levels of trace elements in both rice and wheat flour were detected (p < 0.05), which may be related to local economic indicators. The hazard index (HI) of trace elements in rice samples from all origins exceeded 1, mainly due to the contribution of As, suggesting a potential non-carcinogenic risk. The total carcinogenic risk (TCR) for rice and wheat flour of all origins exceeded the safe level.

Organophosphate ester exposure among Chinese waste incinerator workers: Urinary levels, risk assessment and associations with oxidative stress.

Organophosphate esters (OPEs), which are frequently used as flame retardants and plasticizers in versatile products, are readily released to the external environment. Although workers at municipal waste incineration plants may be extensively exposed to OPEs, only scarce health monitoring and risk assessments have been conducted in this population. In this study, we investigated the levels of eight metabolites of organophosphate esters (mOPEs) and the oxidative stress marker 8-hydroxy-2-deoxyguanosine (8-OHdG) in urine samples from 73 waste incinerator workers and 97 general residents from Shenzhen, China between September 2016 and June 2017. The overall detection rate of mOPEs was 82.2 %-100 %, and higher concentrations of di-p-cresyl phosphate and chlorinated mOPEs [bis(2-chloroethyl) phosphate (BCEP), bis(1-chloro-2propyl) phosphate (BCIPP), bis(1,3-dichloro-2-propyl) phosphate) (BDCIPP)] were found among incinerator workers than among general residents. The incinerator workers also showed significantly higher levels of 8-OHdG than general residents, but the measured levels of most mOPEs were not significantly correlated with the level of 8-OHdG; this may be because co-exposure to multiple toxic compounds can lead to oxidative stress. Risk assessment using Monte Carlo simulations revealed that 95 % of the incinerator workers were free from non-carcinogenic effects due to OPEs exposure (hazard index = 0.27, 95 % CI: 0.09, 0.77). However, the carcinogenic risk of tris(2-chloroethyl) phosphate (TCEP) for incinerator workers was between 10-6 and 10-4. These results indicate that incinerator workers are extensively exposed to OPEs, and better protective measures need to be implemented.

A nationwide investigation of perchlorate levels in staple foods from China: Implications for human exposure and risk assessment.

Perchlorate is an emerging pollutant and thyroid toxicant frequently occurred in air, water, soil and various foodstuffs. Rice and wheat flour are the most common staple foods, which could accumulate perchlorate from contaminated soils and irrigation water. However, human exposure to perchlorate via rice and wheat flour consumption has only been investigated to a limited extent. Therefore, we collected 207 rice samples and 189 wheat flour samples from 19 provinces in China to assess the level of perchlorate. The levels of perchlorate in rice and wheat flour ranged from not detected (N.D.) to 28.7 ng/g and less than limits of quantification (

Health risk assessment of perchlorate and chlorate in red swamp crayfish (Procambarus clarkii) in China.

Perchlorate and chlorate are both strong oxidants and thyroid toxicants that are widely distributed in soil, water and human foods. The red swamp crayfish (Procambarus clarkii) is a common aquatic organism that is popular in Chinese culinary dishes. Dietary intake is the main route of human exposure to perchlorate and chlorate, though the health risks of crayfish consumption are unknown. Thus, this study investigated the quantities of perchlorate and chlorate in red swap crayfish from sampling sites in five provinces located near the Yangtze River in China, along with the associated health risks of consuming this species. Perchlorate was detected in 55.6-100 % of crayfish samples in each sampling location, and chlorate was found in 100 % of samples cross all sites. Concentrations of perchlorate in crayfish from upstream provinces (Hubei, Hunan and Jiangxi) were higher than those from downstream provinces (Anhui and Jiangsu). Perchlorate and chlorate concentrations were positively correlated in crayfish, suggesting that chlorate may be a degradation byproduct of perchlorate. The quantities of both pollutants in hepatopancreas tissue were higher than in muscle tissues (p < 0.05), such that we do not recommend ingesting crayfish hepatopancreas. Hazard quotient (HQ) values for chlorate in crayfish were <1 across all provinces, suggesting no potential health risk of chlorate exposure through crayfish consumption. However, perchlorate concentrations in crayfish from the Jiangxi province had an associated HQ value >1, suggesting potential risks for human health. These results will be useful in informing mitigation measures aimed at reducing perchlorate exposure associated with crayfish consumption.