Balancing the benefits and risks of China's national salt iodization policy over 30 years using disability-adjusted life years (DALYs): a systematic review and meta-analysis.

Both insufficient and excessive iodine intake can lead to thyroid-related disorders. Although China has made progress in eliminating iodine deficiency over the past few decades, the incidence of thyroid cancer is increasing. Currently, there is a lack of relevant research on the tradeoff between the benefits and risks of salt iodization in China. In this study, we developed a method that combines the total probability algorithm and disease burden to evaluate the appropriate amount of salt iodization. Following the principle of minimizing the comprehensive disease burden and using the metabolic model of human iodine nutrition. Based on the average national iodine level in water, the optimal iodine content in Chinese salt is determined to be 17 mg/kg. However, iodine content in water is not evenly distributed in China. Approximately 3.23% of administrative villages have water iodine concentrations exceeding 80 ug/L, eliminating the need for iodine fortification in salt. Approximately 83.51% of administrative villages need to continue implementing the salt iodization policy, with the optimal iodine content in salt ranging from 15 to 18 mg/kg. In 13.16% of administrative villages, the iodine content in salt is determined based on the local water iodine concentration, ranging from 0 to 15 mg/kg. Our study cracks open a window of insight suggesting that the optimal iodine content for salt is lower than the existing benchmark dictated by the prevailing policy in China. Hence, there is an urgent need to refine and advance the iodine supplementation strategy in salt to pave the way for precision medicine and health-centric iodine supplementation strategies.

Characterizing the cumulative health risks of 19 kinds of pesticides in Chinese food from the cancer and non-cancer perspective.

Food safety is an important issue of most concern for health, while pesticides are one of the main threats to food safety. In view of the potential health hazard of pesticides in food, the cancer and non-cancer risks were assessed for 19 kinds of pesticides in Chinese food in this study. Furthermore, the health risks of different types of pesticides were compared to uncover the most polluted pesticide types in this study. Results show that methyl parathion, dichlorvos and 2,4-D residues in some food groups exceed the Chinese food standards. The cumulative disease burden of six carcinogenic pesticides for people older than 40 years ranges from 1.03 × 10-6 to 2.27 × 10-6, which exceeds the WHO recommended limit of 10-6. The non-cancer risks of 13 kinds of pesticides are all lower than 1 and will not pose appreciable health risk to the consumers. Livestock and poultry (contribution rate = 38.93%) and Milk and dairy products (contribution rate = 22.38%) are the dominate risk exposure sources for carcinogenic pesticides while staple foods (contribution rate = 31.62%) and vegetables (contribution rate = 21.5%) are the main risk exposure sources for non-carcinogenic pesticides. Comparing the risks of different pesticide types, insecticide is the most harmful category in this study, followed by herbicide and acaricide. This study characterized the health risks of pesticides in Chinese food and provided a scientific basis for pesticide management.

Dietary Exposure and Health Risk of the Emerging Contaminant Fluorinated Liquid-Crystal Monomers.

Fluorinated liquid-crystal monomers (FLCMs) widely used in liquid crystal displays are considered to be a new generation of persistent, bioaccumulative, and toxic contaminants. They have been widely detected in the environment. However, little is known about their occurrence in food and human dietary exposure until now. Herein, we provided an evaluation of dietary exposure and health risks of FLCMs in the Chinese adult population based on the fifth and sixth total diet studies (TDSs). The detection frequencies of FLCMs in the two surveys were 90.5 and 99.5%, with concentrations ranging from not detected ∼72.6 µg/kg wet weight (ww) and ND ∼74.7 µg/kg ww, respectively. All TDS samples contained the multiresidue of FLCMs. The mean estimated daily intakes (EDIs) of FLCMs were 172.86 and 163.10 ng/kg bw/day in the fifth and sixth TDS, respectively. Meats, vegetables, and cereals contributed the most to the EDI of FLCMs. According to the threshold of toxicological concern (TTC) method, the EDIs of 1-fluoro-4-[2-(4-propylphenyl)ethynyl]benzene (4.56 and 3.26 ng/kg bw/day) and 2-fluoro-4-[4'-propyl-1,1'-bi(cyclohexyl)-4-yl]phenyl trifluoromethyl ether (3.12 and 3.28 ng/kg bw/day) were above their TTC value (2.5 ng/kg bw/day), suggesting their potential health risk. This is the first comprehensive national dietary exposure assessment of FLCMs.

Development of a data driven model to screen the priority control pesticides in drinking water based on health risk ranking and contribution rates.

Pesticides are pollutants of high concern in drinking water. Several approaches aimed to promote pesticide risk management in drinking water have been brought forward by diverse ways, however, these methods usually take too many indicators into consideration, which are complex and non-universal. In this study, a more focused and data driven ranking model was proposed for the purpose of development of the priority control list in drinking water. By determining three parameters including the total health risks of dietary exposure pathways, drinking water contribution rates, and the drinking water health risks, pesticides could be divided into four categories including the priority control list, secondary control list, candidate control list, and non-regulatory list. As a case study, the proposed model was implemented for 23 pesticides detected in drinking water from 36 major cities across China during two major science and technology program for water pollution control and treatment. Totally 13 kinds of pesticides including carbofuran, dicofol, chlorpyrifos, 2,4-D, acetochlor, deltamethrin, dimethoate, heptachlor, parathion, hexachlorobenzene, DDT, hexachlorocyclohexane and atrazine are selected for priority control, methyl parathion, dichlorvos and chlorothalonil are recommended for secondary control, butachlor and malathion are classified into candidate control list, and fenobucarb is suggested to be removed from the pesticide control list.

Application of the health risk assessment of acetochlor in the development of water quality criteria.

Acetochlor is a widely used herbicide in agricultural production. Studies have shown that acetochlor has obvious environmental hormone effects, and long-term exposure may pose a threat to human health. To quantify the hazards of acetochlor in drinking water, a health risk assessment of acetochlor was conducted in major cities of China based on the data of acetochlor residue concentrations in drinking water. The approach of the Species Sensitivity Distributions (SSD) method is used to extrapolate from animal testing data to reflect worst case human toxicity. Results show that hazard quotients related to acetochlor residues in drinking water for different age groups range from 1.94 × 10-4 to 6.13 × 10-4, so, there are no indication of human risk. Compared to the total estimated hazard quotient from oral intake of acetochlor, the chronic exposure imputed to acetochlor residues in drinking water in China accounts for 0.4%. This paper recommends 0.02 mg/L to be the maximum acetochlor residue concentration level in drinking water and source water criteria.

Gross alpha and beta measurements in drinkable water from seven major geographical regions of China and the associated cancer risks.

In this study, human health risk derived from radioactive pollution in drinking water of China was assessed based on gross alpha and beta. Considering the presence of numerous data under the detection limits, the left-censored handling methods were employed to deal with the non-detected values in gross alpha and beta radioactive concentrations. Results show that concentrations of gross alpha and beta range from 4.98 × 10-4 Bq/L to 0.49 Bq/L with a mean value of 0.029 Bq/L and 5.00 × 10-3 Bq/L to 1.26 Bq/L with a mean value of 0.091 Bq/L, respectively. With the average effective dose being 1.41 × 10-2 mSv/y, the annual cancer risk due to radioactive pollution in Chinese drinking water is 7.75 × 10-7 /y. This study aimed to provide an easier method to quantify the radioactive pollution in drinking water and give a scientific basis for making policy decisions on radioactive pollution management.

Co-infection risk assessment of Giardia and Cryptosporidium with HIV considering synergistic effects and age sensitivity using disability-adjusted life years.

Co-infection with multiple pathogens, especially the spread of Giardia and Cryptosporidium in source water among those with immunodeficiency, is common worldwide, which will result in an increase in overall risk. In this study, the quantitative microbial risk assessment model was used to estimate the cumulative risk of co-infection with Giardia and Cryptosporidium promoted by HIV, considering age sensitivity. The sensitivity of population segments with different ages was estimated by the optimization method, based on clinical data of cryptosporidiosis and giardiasis with age structure. The factors of co-infection enhancement were used to quantify HIV synergism with the action of other pathogens. The removal rates of Giardia and Cryptosporidium through water treatment were estimated by a model involving turbidity and particles. The results showed that children (0-4 years) were 17.911-fold more sensitive to infection with Giardia than adults (15-64 years), and that with Cryptosporidium was 10.592-fold. Removal rates of these parasites in water treatment plants in major cities in China were estimated to be 2.03 log10. Considering the HIV-synergistic and age-susceptibility effects, the cumulative risk of exposure to Giardia or Cryptosporidium was about 38.781 × 10-6DALYs (Disability-adjusted life years) per person per year, which was much higher than the reference risk level recommended by the World Health Organization (10-6DALYs). The methodology and results of this study will be useful in better evaluating and reducing the burden due to infection of Giardia and/or Cryptosporidium in China and other countries.

Chronic health risk comparison between China and Denmark on dietary exposure to chlorpyrifos.

Chlorpyrifos is one of the most heavily used pesticides in domestic and agricultural insect prevention globally. Given the potential neurotoxicity of chlorpyrifos and its high detection rates in food and drinking water, health risks attributable to chlorpyrifos residue in Chinese drinking water and food in both China and Denmark were assessed in this study. Mixed left-censored handling models were used to deal with the non-detected values in chlorpyrifos concentrations. Results show that chronic exposure imputed to chlorpyrifos residue is much lower than the reference dose, and will thus not pose appreciable health risk to the consumer. Compared to the total exposure from chlorpyrifos in drinking water and food sources, chronic exposure from drinking water sources in China accounts for 0-4.4%. Health risk owing to chlorpyrifos in food within China is 6-7-fold higher than in Denmark, and this coincides with the fact that all application of chlorpyrifos is banned in Denmark, in contrast to China. However, the Danish consumers are still exposed from imported food items. The main health risk contributors in China are the food groups of Grains and grain-based products and Vegetable and vegetable products, while the main chronic health risk contributor in Denmark is the food group of imported fruit and fruit products.

Health risk assessment on N-nitrosodimethylamine in drinking water and food in major cities of China with disability-adjusted life years (DALYs).

In this study, a health risk assessment of N-nitrosodimethylamine (NDMA) in drinking water and food was conducted using disability-adjusted life years (DALYs) in major cities of China. Considering the numerous non-detected values found in drinking water samples, a zero-inflated model was employed to obtain a more precise NDMA concentration distribution function in drinking water. With exogenous chronic daily intake of 1.20 × 10-6 mg/(kg*d), the lifetime cancer risk and disability-adjusted life years of NDMA are 4.01 × 10-5 and 5.52 × 10-6 per person-year (ppy). The disease burden attributable to water sources accounts for nearly 9.94% of total exogenous intake. The contribution rate of vegetables is the largest, followed by cereals, milk products, fish and shrimp, and meat. Taking endogenous sources into consideration, the contribution rates of drinking water and food sources decrease to 0.08% and 0.69%. This study provides a scientific basis for making policy decisions on NDMA pollution management.