Effect of maternal tobacco smoking or exposure to second-hand smoke on the levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in urine of mother and the first urine of newborn

Tobacco smoking during pregnancy is associated with a variety of negative consequences not only for the mother, but also for the developing fetus. Many studies have shown that carcinogens contained in tobacco smoke permeate across the placenta, and are found in fetus. The aim of the study was to determine the prenatal exposure to tobacco-specific carcinogenic N-nitrosamines on the basis of measurements of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in urine of smoking and second-hand smoke (SHS) exposed women and in the first urine of their newborns. A questionnaire documenting demographics and socio-economical data, smoking habits and exposure to SHS was completed by 121 delivering women near or at term. Maternal concentrations of cotinine and NNAL were measured in urine of the mother and the first urine of her newborn infant by liquid chromatography tandem mass spectrometry (LC/MS/MS). The mean concentration of cotinine was 439.2 ng/mg creatinine and NNAL concentration in urine of smoking women was 74.0 pg/mg creatinine, and for her newborn 78.6 pg/mg creatinine. Among mothers exposed to SHS, cotinine and NNAL mean concentration were 23.1 ng/mg creatinine, and 26.4 pg/mg creatinine. In newborns of SHS exposed mothers during pregnancy the mean concentration of NNAL was 34.1 pg/mg creatinine, respectively. Active tobacco smoking as well as passive exposure to smoking during pregnancy is an important source of tobacco specific N-nitrosamines to the fetuses as evidenced by increased concentrations of this carcinogen. Determination of NNAL in maternal urine samples can be a useful biomarker of prenatal exposure of newborn to carcinogenic nitrosamines.     

Tissue-specific inhibition of [3H]thymidine incorporation into DNA by carcinogenic N-nitrosamines

The N-nitrosamines N-nitrosodimethylamine (DMN), N'-nitrosonornicotine (NNN) and 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were injected intraperitoneally 24 h before sacrifice in F344 rats and C57BL mice in doses of 297 mumoles/kg b.w. and 148 mumoles/kg b.w., respectively. 2 h before sacrifice, the animals were given an intraperitoneal injection of [3H]thymidine. The results showed that the examined N-nitrosamines inhibited the incorporation of [3H]thymidine into DNA in a few tissues of the rats and the mice. The results indicated that the N-nitrosamines exerted a tissue-specific inhibition of the [3H]thymidine incorporation in the tissues reported to be involved in the biotransformation of these substances. The observed inhibitory effects on the incorporation of [3H]thymidine by DMN, NNN and NNK were also correlated to a considerable extent to the reported sites of carcinogenicity. The present study indicates that measurements of [3H]thymidine incorporation into DNA in various tissues of experimental animals is a useful short-term bioassay to evaluate the potential tissue-specific carcinogenicity of the N-nitrosamines. The method may also be useful as a complement to other short-term in vivo tests in the screening of potential genotoxicity of several other chemicals.     

Chromium,Copper, and Arsenic Concentrations in Soil Underneath CCA-Treated Wood Structures

Soils below nine structures (decks and foot bridges) in Florida were examined to evaluate potential impacts from chromated copper arsenate (CCA), a common wood preservative. Eight of the nine structures were confirmed to have been treated with CCA. Soils collected were evaluated for arsenic, chromium, and copper concentrations as well as pH, volatile solids content and particle size distribution. Two types of soil samples were collected: a soil core and surface soil samples (upper 2.5 cm). One soil core was collected from below each deck and one control core was collected from an area removed from one of the structures. Eight or nine surface soil samples were collected in a grid-like fashion from beneath each structure. Equal numbers of surface control samples were collected from areas away from the structures. Metal concentrations were elevated in both the soil cores and surface samples collected from below the CCA-treated structures. Core samples showed elevated concentrations of metals at depths up to 20 cm. The arithmetic mean concentrations of arsenic, chromium, and copper in the 65 surface soil samples collected from below CCA-treated structures were 28.5 mg/kg, 31.1 mg/kg, and 37.2 mg/kg, respectively, whereas the mean concentrations of arsenic, chromium, and copper in the control samples were 1.34 mg/kg, 8.62 mg/kg, and 6.05 mg/kg, respectively. Arsenic concentrations exceeded Florida's risk-based soil cleanup target level (SCTL) for residential settings in all 65 surface soil samples. The industrial setting SCTL was exceeded in 62 of the 65 samples.     

张家界市部分农作物可食部位硒含量研究

采用国家标准( GB/T5009.93-2003),用荧光分光光度计对张家界市22种农作物40个样本可食部位中的硒含量进行了分析.结果表明,测定的22个种类40个样本均属于富硒及高硒作物,以茶叶的硒平均含量最高为2.0102 mg/kg,其次是豆类平均含量为1.8518 mg/kg,薯类含量最低为1.0240 mg/kg.所测定的各种作物可食部位富硒能力依次为:茶叶2.0102 mg/kg＞豆类(干)1.8518 mg/kg＞水稻、玉米1.5326 mg/kg＞蔬菜类1.3438 mg/kg＞水果类1.0783 mg/kg＞薯类1.0240 mg/kg.该研究确定了部分农作物硒含量的水平及富硒作物品种.     

Flow of toxic metals in food-web components of tropical mangrove ecosystem,Southern India

The concentration of heavy metals in water, sediment, and various food-web components like plankton, shrimp, bivalve, and fishes were collected from Muthupet mangrove ecosystem. Heavy metal concentration in water samples was relatively lesser than the biological and sediment samples. Among the heavy metals studied, zinc showed highest concentration ranged from 1.81 to 81.5 mg/kg or mg/L, whereas Cd (0–26.06 mg/kg or mg/L) was found to be lesser in all the samples except a few organisms viz. Anadara sp. (26.06 mg/kg), Coilia sp. (10.09 mg/kg), Anguila sp. (9.14 mg/kg), and Tachysurus maculates (6.95 mg/kg) observed during this study. Pb and Cu were ranged from 10.29 to 14.99 mg/kg and 0.59 to 16.06 mg/kg, respectively. The reported values of heavy metals were several folds higher than permissible levels of international regulatory agencies like WHO, FAO, and USEPA. The order of accumulation of heavy metals in biological samples are as follows: Pb > Cu > Zn > Cd. All the biota showed a higher degree of bioconcentration factor for Zn, in the range of 3.90–34.39. Principal component analysis concluded that Muthupet was contaminated by lithogenic as well as anthropogenic activities.Therefore, field observation and sample analysis clearly indicated that sampling sites were polluted with both point and nonpoint source of pollution.     

Heavy Metal Concentration in Sediments of the Nhue River and its Water-Irrigated Farmland Soil in the Suburbs of Hanoi,Vietnam

The heavy metal pollution of sediment in the Nhue River, which receives wastewater from the To Lich and Kim Nguu River system, was investigated together with the effects of use of this water for irrigation of the surrounding farmland. Eighty soil samples and 40 sediment samples were collected from six locations in the Nhue River and two locations in the To Lich River for chemical and physical analyses. The results showed that the sediments in the Nhue River are heavily polluted by metals (71–420 mg/kg for Cu, 77–433 mg/kg for Pb, 150–350 mg/kg for Zn, 0.7–8.7 mg/kg for Cd, 80– 583 mg/kg for Cr, and 32–70 mg/kg for Ni). There were positive correlations between heavy metal concentration and both clay and organic matter contents in the sediment samples. The concentrations of all metals in soil samples were much higher than the background levels in the farmland, Cd, Cu, and Pb, exceeding Vietnamese standards for agricultural grounds.     

Trace Elements in Street and Household Dusts in Amman,Jordan

This research aims at quantifying the concentrations of heavy metals within the home environment in Amman, the capital city of Jordan, and to compare the total concentrations of indoor dusts to that of exterior dusts and soils. Housedust samples were collected from different zones of Amman. Street dust samples and garden soil samples were collected in the immediate vicinity within 10–50 m of each residence. The geometric mean concentrations of metals in the household dust were Pb, 169 mg/kg; Cd, 2.92 mg/kg; Zn, 1985 mg/kg; Cu, 133 mg/kg; Cr, 66 mg/kg; Co, 21 mg/kg; Ni, 31 mg/kg; Mn, 284 mg/kg; Be, 3.0 mg/kg; Ba, 43 mg/kg; B, 697 mg/kg and Al, 1441 mg/kg. Comparisons of household dust, garden soil and street dust were based on the same particle size fraction. Results showed housedust samples to contain higher concentrations for Pb, Zn, Cr, Ni, Cd, Cu and B, than either street dust or garden soil samples. However, the differences between Pb and Cr levels in the three different sample categories were insignificant. Enrichment factor calculations and the enrichment factor ratios indicated that patterns of enrichment of indoor dust differ from that of exterior dusts.     

Mycotoxins in cereal grain (part 15). Distribution of deoxynivalenol in naturally contaminated wheat kernels

The analysis of deoxynivalenol (DON) in naturally infected wheat samples, after having been separated into four fractions through laboratory sieves, showed very low levels of DON in the fraction of largest kernels >2.8 mm (0 up to 1 mg/kg). The highest concentration of DON was found in fractions 2.2 to 2.5 mm and <2.2mm with up to 14mg/kg and 15mg/kg DON, respectively. In two samples (fractions <2.2mm) nivalenol was detected in concentrations up to 1,4mg/kg.     

Levels of hexachlorocyclohexanes in agricultural environment of Sacco river valley

Aim of this trial was to verify the occurrence and the distribution of hexachlorocyclohexanes (HCHs) in soil, sediment, straw, alfalfa, other animal feed grown in farms with contaminated soil. In the present study two years of monitoring activity in the province of Roma and Frosinone was reported. Experimental trial in two contaminated sites was carried out on uptake and translocation of HCHs in maize and alfalfa. In 19 sites soil, forage and weed has been collected for two years, soil samples consisted in cores of 40 cm to test the presence of HCHs at different deep. The analytical determinations in soil and plant samples were carried out by gas liquid chromatography with electron capture detector and confirmed by mass detector. In the first year (2005- 2006) 68% of soil samples were contaminated (HCHs > LOQ) and 3% of vegetable samples. In the second year (2006- 2007) 42% of soil samples resulted positive and 26% of vegetable matrix. In particular B hexacyclohexane was detected in wheat stem (0.037 mg/kg) with a soil contamination of 0.039 mg/kg and in alfalfa (0.012 mg/kg) with presence in soil of 0.004 mg/kg. Experimental trials on maize evidenced a translocation factor for this isomer stem/soil of 0.006 mg/kg ? and for grain of 0.005 mg/kg. On alfalfa translocation factor root/soil was 0.01 and shot/soil 0.009. A propose to calculate the threshold value of soil contamination to admit crop grown destined to animal feed, would be based on HCHs LOD values weighted with translocation factor.     

城市周边生活污水排放对绿地土壤环境质量的影响

大城市郊区的小型居住区,将生活污水未经处理直接排入附近的绿地是比较常见的.这种直接排放虽然利用了有限水源,但对绿地土壤带来环境影响.为了研究这类排放对周边土壤环境的影响,选择了京郊一处接受附近生活污水直接排放的绿地,取其污水排放口附近的土壤样品为实验对象,以远离该点的土样为对照来研究生活污水排放对周边土壤环境质量的影响.模糊聚类分析结果表明:与对照点相比,生活污水排放提高了排放口附近土壤的养分含量,土壤pH值由8.9降低至7.32,有机质含量由1.7873%提高到5.9455%,钾含量由220 mg/kg提高到1230 mg/kg,磷含量由11.8 mg/kg提高到150.72mg/kg,全氮含量由0.1078%提高到0.5325%,重金属铅含量由52.87 mg/kg提高到129.53mg/kg、镉含量由0.7525mg/kg提高到2.5692mg/kg.铅含量达到了国家二级标准,而镉含量超过了国家三级标准,存在严重的土壤环境污染.     

Monitoring of individual human exposure to aflatoxins (AF) and N-nitrosamines (NNO) by immunoassays

Highly sensitive immunoassays have been used to quantitate aflatoxins (AF) and N-nitrosamines (NNO) in human body fluids and tissues, respectively. This approach was taken in order to quantitate environmental exposure to these agents at an individual level to facilitate the investigation of their role in the etiology of human cancer. In order to analyse AF in human urine, an immunopurification step has been developed by using AF-specific antibody bound to AH-Sepharose 4B gel in a small (4-ml gel volume) affinity column prior to enzyme-linked immunosorbent assay (ELISA). The ELISA can be used to quantitate aflatoxin B1 (AFB1) over the range 0.01 ng/ml to 10 ng/ml and the assay system has been validated by using human urine samples spiked with AFB1 over this concentration range. In addition, 29 urine samples from the Philippines have been analysed and found to contain a range of levels from zero to 4.25 ng/ml AFB1 equivalent with a mean of 0.875 ng/ml. This compared with a mean of 0.066 ng/ml AFB1 equivalent in samples from France. Radioimmunoassay of O6-methyldeoxyguanosine (O6-medG) has been performed on human oesophageal and cardiac stomach mucosal DNA from tissue samples obtained during surgery in Linxian County, People's Republic of China, an area of high risk for both oesophageal and stomach cancer. Using the methodology described and having 1 mg of hydrolyzed DNA allows the detection of approximately 25 fmol O6medG per mg DNA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ochratoxinogenicity of Aspergillus ochraceus strains from nephropathic and non-nephropathic areas in Yugoslavia

Mycological analyses of 855 samples of stored grains and dried meat collected in period 1980–1987 from individual households in the nephropathic and wider non-nephropathic area in SR Croatia in Yugoslavia showed 10% of samples to be contaminated with Aspergillus ochraceus. Ability to produce ochratoxin A (OA) was tested in 70 samples (27 from nephropathic areas and 43 from non-nephropathic areas). The detection was carried out under UV-light (365 nm) (light blue fluorescence) and 6 OA-producers were found.A biosynthetic procedure on liquid nutritional substrate with sacharose and yeast extract as well as a method using wet crushed wheat revealed that 37% of the samples from a nephropathic area, and 35% of the samples from a non-nephropathic area produce OA.In the nephropathic area 1/10 strains was a strong producer of OA (concentration crushed wheat 135 mg/kg, and 240 mg/l on YES liquid substrate), 1/10 strains was a moderate producer (concentration 16.6 mg/l and 0.07–7.0 mg/l and 0.1–10.4 mg/kg).Among the strains isolated from a wider non-nephropathic area no strong producers of OA were found, but 2/15 strains were moderate producers of OA (concentration of OA 20.4–27.0 mg/l and 15.0–33.7 mg/kg). The other strains, 8/10 on the crushed wheat and 13/15 on the liquid substrate, were weak producers of OA with concentrations of OA between 0.2–9.0 mg/l and 0.2–10.0 mg/kg with the two methods respectively.     

Serum organochlorine pesticides residues and risk of cancer: A case-control study

Organochlorine pesticides (OCPs) are frequently used worldwide as insecticides, fungicides, herbicides and termiticides and have been associated with a variety of cancers in animal and human studies. In the present study, we examined residues of fourteen OCPs in the serum samples of diagnosed cancer patients and healthy residents of Karachi, Pakistan. A random collection of fasting blood samples was carried out from the donors with informed consent. Serum was separated within 2?h of blood collection and was then subjected to extraction with organic solvents followed by purification with florisil column. The final organic extract of each serum sample was processed with Gas Chromatograph coupled with Electron Capture Detector (GC-ECD). OCPs were detected in 97.59% of the cancer cases and 93.75% of the healthy subjects. Mean concentrations of total OCPs (ΣOCPs) was found elevated in the cancer group (0.606?mg/kg) compared with the control group (0.322?mg/kg). Endosulfan was the highest prevalent OCP with a mean concentration of 0.214?mg/kg in the cancer group and 0.166?mg/kg in the control group. The second most prevalent OCP was 4,4-DDE with a mean concentration of 0.131?mg/kg in the cancer group and 0.019?mg/kg in the control group. Highest level of ΣOCPs was detected in the breast cancer cases (20.411?mg/kg) with a mean level of (2.041?mg/kg). In light of the obtained results and available literature on the subject, it has been concluded that OCPs are positively associated with the risk of various cancers in humans.     

Influence of acidic beverage (Coca-Cola) on pharmacokinetics of ibuprofen in healthy rabbits

The study was aimed at determining the effect of Coca-Cola on the pharmacokinetics of ibuprofen in rabbits. In a cross-over study, ibuprofen was given orally in a dose of 56 mg/kg, prepared as 0.5% suspension in carboxymethyl cellulose (CMC) and blood samples (1 ml) were drawn at different time intervals from 0-12 hr. After a washout period of 7 days, Coca-Cola in a dose of (5 ml/kg) was administered along with ibuprofen (56 mg/kg) and blood samples were drawn from 0-12 hr. To these rabbits, 5 ml/kg Coca-Cola was administered once daily for another 7 days. On 8th day, Coca-Cola (5 ml/kg) along with ibuprofen (56 mg/kg), prepared as a suspension was administered and blood samples (1 ml each) were drawn at similar time intervals. Plasma was separated and assayed for ibuprofen by HPLC technique and various pharmacokinetic parameters were calculated. The Cmax and AUC0-alpha of ibuprofen were significantly increased after single and multiple doses of Coca-Cola, thereby indicating increased extent of absorption of ibuprofen. The results warrant the reduction of ibuprofen daily dosage, frequency when administered with Coca-Cola.     

Environmental risks posed by heavy metal contamination from mine waste: Case study from northwest Iran

Mining activities produce waste tailings that can be a significant source of pollution in the surrounding ecosystem. This study was designed to estimate the magnitude of Fe, As, Pb, Cd, Mn, Ni, Zn, and Cr in soil impacted by activities in the Moeil iron ore mine area of northwestern Iran and initially assess the potential risk to nearby residents and ecological habitats. For this, concentrations of elements in 24 samples from 8 locations were analyzed by inductivity coupled plasma optical emission spectrometry. Concentrations of heavy metals reported for samples collected from the area ranged from 50,247–466,200 mg/kg for Fe, 40–10,827 mg/kg for As, 9–84 mg/kg for Pb, 0.2–58.4 mg/kg for Cd, 32–424 mg/kg for Mn, 4–32 mg/kg for Ni, 37–60 mg/kg for Zn, and 32–337 mg/kg for Cr. Reported levels of Fe and As in particular are indicative of severe contamination and imply a high risk to ecological receptors. Reported levels of arsenic also imply elevated cancer and non-cancer health risks to residents who work in or pass through the area. Reported levels of Cd and Cr in soil samples also indicate an elevated cancer risk posed by these metals. The result of this study indicates it is important to estimate potential contamination of soils and drinking water wills in the vicinity of Moeil village to arsenic and heavy metals.     

Analysis of minor components in olive oil

Virgin olive oil is well known for its high content of phenolic substances that are thought to have health-promoting properties. These substances also contribute to the distinctive taste of the oil. In this study, tyrosol, vanillic acid, luteolin, and apigenin were identified and quantified by liquid chromatography mass spectrometry (LC-MS). In the seven samples analysed, tyrosol, the most abundant, was in the range of 1.4-29 mg/kg, vanillic acid was in the range of 0.67-4.0 mg/kg, luteolin was in the range of 0.22-7.0 mg/kg, and apigenin was in the range of 0.68-1.6 mg/kg. It was also shown that in olive oil, squalene can be analysed by using a refractive index detector. In the samples analysed, squalene occurred in the range of 3.9-9.6 g/l.     

Study of the environmental hazard caused by the oil shale industry solid waste

The environmental hazard was studied of eight soil and solid waste samples originating from a region of Estonia heavily polluted by the oil shale industry. The samples were contaminated mainly with oil products (up to 7231mg/kg) and polycyclic aromatic hydrocarbons (PAHs; up to 434mg/kg). Concentrations of heavy metals and water-extractable phenols were low. The toxicities of the aqueous extracts of solid-phase samples were evaluated by using a battery of Toxkit tests (involving crustaceans, protozoa, rotifers and algae). Waste rock and fresh semi-coke were classified as of "high acute toxic hazard", whereas aged semi-coke and most of the polluted soils were classified as of "acute toxic hazard". Analysis of the soil slurries by using the photobacterial solid-phase flash assay showed the presence of particle-bound toxicity in most samples. In the case of four samples out of the eight, chemical and toxicological evaluations both showed that the levels of PAHs, oil products or both exceeded their respective permitted limit values for the living zone (20mg PAHs/kg and 500mg oil products/kg); the toxicity tests showed a toxic hazard. However, in the case of three samples, the chemical and toxicological hazard predictions differed markedly: polluted soil from the Erra River bank contained 2334mg oil/kg, but did not show any water-extractable toxicity. In contrast, spent rock and aged semi-coke that contained none of the pollutants in hazardous concentrations, showed adverse effects in toxicity tests. The environmental hazard of solid waste deposits from the oil shale industry needs further assessment.     

Background levels of polycyclic aromatic hydrocarbons (PAH) and selected metals in new England urban soils

Polycyclic aromatic hydrocarbons (PAH) are byproducts of combustion and are ubiquitous in the urban environment They are also present in industrial chemical wastes, such as coal tar, petroleum refinery sludges, waste oils and fuels, and wood‐treating residues. Thus, PAHs are chemicals of concern at many waste sites. Risk assessment methods will yield risk‐based cleanup levels for PAHs that range from 0.1 to 0.7 mg/kg. Given their universal presence in the urban environment, it is important to compare risk‐based cleanup levels with typical urban background levels before utilizing unrealistically low cleanup targets. However, little data exist on PAH levels in urban, nonindustrial soils. In this study, 60 samples of surficial soils from urban locations in three New England cities were analyzed for PAH compounds. In addition, all samples were analyzed for total petroleum hydrocarbons (TPH) and seven metals. The upper 95% confidence interval on the mean was 3 mg/kg for benzo(a)pyrene toxic equivalents, 12 mg/kg for total potentially carcinogenic PAH, and 25 mg/kg for total PAH. The upper 95% confidence interval was 373 mg/kg for TPH, which exceeds the target level of 100 mg/kg used by many state regulatory agencies. Metal concentrations were similar to published background levels for all metals except lead. The upper 95% confidence interval for lead was 737 mg/kg in Boston, 463 mg/kg in Providence, and 378 mg/kg in Springfield.     

Occurrence of<Emphasis Type="Italic">Fusarium</Emphasis> toxins in the 1999’s harvest

Continuing the monitoring ofFusarium toxins in cereals, we investigated 245 samples of wheat, barley, triticale and oats in 1999. 84 samples out of 100 analysed forFusarium could be found to be infected. The most prominentFusarium species detected whereF. avenaceum, F. poae, F. detected whereF. avenaceum, F. poae, F. graminearum, andF. sporotrichoides. The level of mycotoxin contamination of the samples varied depending on their origins and was in general very low in comparison with the result obtained in samples of the previous year. There where only some wheat samples with deoxynivalenol (DON) concentrations beyond existing advisory levels. The average DON concentration of all samples was 0.35 mg/kg with a median of 0.007 mg/kg. 3-Acetyldeoxynivalenol and zearalenone (ZEA) could only be detected at minor concentrations (below 0.1 and 0.05 mg/kg, respectively) in less than 10% of the samples. The analysis of commercial cereal flour reflects this situation. Flour bought in the first quarter of 1999, which was suspected to contain a high portion of the 1998 harvest, was contaminated by DON to a higher extent than those purchased in 2000. The average DON concentration in the flour samples of 1999 and 2000 was 0.35 mg/kg and 0.23 mg/kg, respectively. Although the general mycotoxin level in the 1999 harvest was lower as in 1998 there were some highly contaminated samples that had mainly been grown in fields with either maize or other cereals as previous crop and reduced tillage. The combination of maize as previous crop and non-tillage could be stated as most unsuitable, which promotes enhanced mycotoxin contamination, and should therefore be avoided.     

Association of selenium levels with the prevention and control of Keshan disease: A cross-sectional study

PurposeThe prevalence of Keshan disease (KD) is low and has reached controlled or eliminated levels even in counties that had a high KD prevalence in the past. Few nationwide surveys on selenium levels in KD areas have been conducted in the past 2 decades. We conducted a cross-sectional study to investigate the selenium levels and their association with KD control and prevention in areas where KD is prevalent.MethodsWe collected 2143 human-hair, 698 soil, 701 rice, 607 flour, 521 corn, and 330 other-food samples from 49 counties with KD and 19 non-KD counties of nine KD provinces of China. The selenium content of samples was examined with hydride generation atomic fluorescence spectrometry. The difference in selenium levels between the KD and non-KD areas was analyzed. Cochran–Armitage trend tests were used to evaluate the association between selenium levels and KD control.ResultsThe selenium levels in human hair, soil, staple foods, and other foods in the KD areas (0.2996 mg/kg, 0.1380 mg/kg, 0.0190 mg/kg and 0.0076 mg/kg, respectively) were lower than those in the non-KD areas (0.3700 mg/kg, 0.1930 mg/kg, 0.0240 mg/kg and 0.0165 mg/kg, respectively). The Cochran–Armitage tests showed that there was a trend for the selenium standard ratio in the counties to increase in the order of KD uncontrolled, to controlled, to eliminated (Z = 2.229, P < 0.05).ConclusionThe residents in the KD areas were found to be selenium-deficient. Improving the supply of staple foods containing selenium levels exceeding 0.025 mg/kg and abundant foodstuffs might contribute to KD control and prevention.