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The southward extension of the Bangong-Nujiang Suture and the late Mesozoic tectonic affinity of the Tengchong Block have been subject to debate, and the Early Cretaceous magmatism in the eastern Tengchong Block provides a crucial window to address these issues. This paper reports comprehensive petrographic, geochemical, geochronological, and isotopic data of Early Cretaceous granitic rocks from the eastern Tengchong Block. Results show that these granitic rocks consist of monzogranites and granodiorites, with zircon U-Pb ages of 120.4–113.9 Ma. These granitic rocks are characterized by enrichments in large ion lithophile elements (e.g. Rb, U, K) and light rare earth elements, but depleted in high field strength elements (e.g. Nb, Ta, P, Ti), and have negative apatite εNd(t) values (−10.4 to −6.7) and negative zircon εHf(t) values (−11.7 to −1.2). The molar [Al2O3/(CaO + K2O + Na2O)] (A/CNK) values and whole-rock zircon saturated temperatures of the studied monzogranites of 1.04–1.09 and 714–799°C, respectively, indicate that they have I-type granite affinity. The presence of biotite indicative of I-type granite and the observation that P2O5 decrease with increasing SiO2 further indicated that the monzogranites have affinities of I-type granites. The petrography, geochemical and isotopic signatures of the studied monzogranites indicate that they originated from partial melting of mafic lower crustal rocks. The Na-rich granodiorites have elevated Na2O/K2O ratios and Na2O contents of 1.19–2.04 and 3.12–3.47 wt.%, respectively. These granodiorites also have relatively high Mg# values and the transition metal element Cr of 53.3–54.5 and up to 100 ppm, respectively. According to these isotopic and geochemical features and the occurrence of magnesiohornblende, we propose that the Na-rich granodiorites were derived from partial melting of ancient basaltic lower crust, with certain inputs of mantle materials in the magma source. Considering these results as well as published data, we finally propose that the Tengchong Block was likely the southeastern extension of the Lhasa Block and that these Early Cretaceous granitic rocks were formed in the setting of the volcanic arc due to westward subduction of the Bangong-Nujiang Tethys oceanic lithosphere beneath the Tengchong Block. [ABSTRACT FROM AUTHOR]

The Central Asian Orogenic Belt (CAOB) is the largest accretionary orogenic belt in the world and its formation involved a complicated process of arc–continent collision. Large‐scale Mesozoic volcanic activity in the Great Xing'an Range (GXAR) in northeastern China, which constitutes part of the eastern CAOB, has received much recent research attention. However, the petrogenesis and formation mechanism of the late Mesozoic igneous rocks remain enigmatic. This paper investigates the geochronology, petrogenesis, and formation mechanism of late Mesozoic magmatic rocks in the Kelihe area of the GXAR based on zircon U–Pb dating, petrology, and geochemistry. Late Mesozoic magmatism in the Kelihe area occurred during the Late Jurassic (165–155 Ma) and Early Cretaceous (130–120 Ma). These igneous rocks generated by this magmatism are characterized by high SiO2 (69.97–75.49 wt%) and low MgO (0.11–0.68 wt%), Cr (10–30 ppm), Co (0.2–2.6 ppm), and Ni (0.5–1.6 ppm) contents. Trace elements show enrichment in Rb, Th, U, Zr, and K, and depletion in Ba, P, Nb, and Ti. These features indicate that the rocks were derived from partial melting of the crust. Furthermore, the rhyolites have high Na2O (5.02–5.44 wt%) and K2O (3.94–4.88 wt%) contents, similar to those of melts formed by the partial melting of basaltic crust. Combining the present results with the findings of previous studies, it is inferred that the Mesozoic igneous rocks formed in a post‐collisional extensional setting related to lithospheric thinning and asthenospheric upwelling after the closure of the Mongol–Okhotsk Ocean. [ABSTRACT FROM AUTHOR]

Landscape evolution is modulated by the regional tectonic uplift, climate change, and river dynamics. However, how to distinguish these mechanisms through the research of surface exhumation and fluvial incision remains controversial. In this study, cosmogenic 10Be, 26Al, and 21Ne concentrations in quartz from cave deposits, modern river sediments, and bedrocks were measured to constrain the applicability of cosmogenic 21Ne and discuss Quaternary landscape evolution history in the Guizhou Plateau, southeast China. Using the 26Al-10Be and 21Ne-10Be pairs to distinguish the cosmogenic 21Ne concentration from the excess 21Ne, we found that the nucleogenic 21Ne produced by the U and Th decay in quartz is significant in the samples although there is the possibility of inherited cosmogenic 21Ne. Combining with previous studies, we suggest that the precise approach for applying the cosmogenic 21Ne could be reached by (1) estimating the contribution from nucleogenic 21Ne, (2) avoiding samples with complex burial histories to exclude inherited cosmogenic 21Ne, and (3) combining the 10Be-26Al-21Ne nuclides method for the Quaternary samples. In addition, both pre-burial basin denudation rates and burial ages derived from the 26Al-10Be pair were used to determine the different timescale surface denudation rate and fluvial incision rate in relation to previous work. The consistency of the different timescales pre-burial basin denudation rate, 36Cl surface denudation rate, and modern basin denudation rate indicates that the landscape-scale surface denudation has been likely stabilized since the Quaternary in the Guizhou Plateau area. The slightly higher river incision rates than the local surface denudation rate show that the river dynamics may not have reached a steady-state due to the regional tectonic uplift in the Guizhou Plateau. [ABSTRACT FROM AUTHOR]

The Neoarchean charnockite of Yinshan Block has been a hot topic into understanding the Precambrian geology of the North China Craton. Although there is a broad consensus that the charnockite is usually related to granulite‐facies metamorphism, its petrogenesis and tectonics still remain controversial. We present a comparative study of the petrography, geochemistry, and geochronology of charnockite and intermediate–basic granulite in the Jining area along the northern margin of the North China Craton. Inclusions within hypersthene in charnockite are used to identify the peak granulite facies mineral assemblage, with the formation of charnockite being attributed to anatexis of the protolith associated with this granulite‐facies metamorphism. Anatexis occurred mainly during postpeak isothermal decompression, as inferred from the metamorphic evolution and pressure–temperature conditions (granulite and charnockite record peak pressure–temperature conditions of 750°C–1,000°C and 0.8–1.2 GPa and 850°C–975°C and 0.9–1.0 GPa, respectively) derived from analyses of metamorphic minerals using electron probe microanalysis, combined with previous zircon geochronology. Hypersthene in charnockite is interpreted to be a residual or peritectic mineral phase that was present during anatexis, and the charnockite is inferred to have been crystallized from a melt containing abundant residual minerals. Charnockite has similar geochemical characteristics to those of intermediate–basic granulite but differs in several key ways: (a) The charnockite is strongly depleted in the large‐ion lithophile element Cs, the heat‐producing elements U and Th, and the high‐field‐strength elements Nb, Ta, P, and Ti; (b) it is enriched in Sr; and (c) it exhibits both positive and negative Eu anomalies, which are characteristics of granites formed largely by in situ anatexis. Geochemical constraints indicate that the intermediate charnockite and retrograde metamorphic biotite–hornblende gneiss may both be the product of mantle‐derived magma in a magmatic subduction‐related back‐arc extensional environment. This setting provided a hot spot for metamorphic anatexis, with additional heat being provided by the upwelling of asthenospheric mantle. After the cessation of subduction by ~2,470 Ma, a magmatic arc extensional setting developed in the Jining area. The charnockite was involved in Paleoproterozoic orogenesis in the North China Craton and was strongly modified by a ~1,950‐Ma metamorphism event. [ABSTRACT FROM AUTHOR]

The Kaiyuan tectonic mélange makes up the western part of the Kaiyuan–Yanji Accretionary Complex Belt, NE China, and there has been a long‐standing controversy about its age and tectonic setting. In this paper, we present new zircon U–Pb ages and geochemical data for the mafic rocks of the Lujiapuzi Formation in the Kaiyuan tectonic mélange, and these data provide insights into the tectonic setting during the late Paleozoic and the evolutionary history of the Paleo‐Asian Ocean in the eastern segment of the Central Asian Orogenic Belt (CAOB). SHRIMP U–Pb dating of zircons from samples of albite–actinolite schist and amphibolite yielded a crystallization age of 258 ± 5.5 Ma for the protoliths, suggesting that the protoliths formed during the late Permian. The albite–actinolite schists and amphibolites have similar geochemical characteristics, and they represent metamorphosed basaltic volcanic rocks. Major, rare earth and trace element data show that the mafic rocks have a close affinity with mid‐ocean ridge basalt. REE petrogenetic modelling indicates that the primary magma was generated through the partial melting of a mixed garnet‐ and spinel‐bearing mantle source, and assimilated crustal material and underwent crystal fractionation during ascent. The geochemical features and inherited/xenocrystic zircons in the mafic samples indicate that they formed in a tectonic setting similar to the back‐arc basin. These new findings, together with other previously published data, indicate that the Paleo‐Asian Ocean still existed in the eastern segment of the CAOB during the late Permian to Early Triassic. The Kaiyuan tectonic mélange formed during the Middle Triassic, and its formation may represent the timing of final closure of the Paleo‐Asian Ocean. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To observe the natural history and to determine appropriate screening interval for esophageal and gastric cardia precursors. Methods: Repetitive endoscopic screenings were performed among 425 forty to sixty-nine-year-old subjects in a high-risk region in Northern China. Results: We observed 8 subjects develop severe dysplasia (SD), another 8 develop carcinomas in situ (Cis), and 4 develop invasive cancer. The time and baseline diagnosis (BD) for the 8 SD subjects were: 13 months after normal epithelium in one case, 7 months after base cell hyperplasia (BCH) in another case, 3, 4, 4, and 10.5 months after mild dysplasia (mD) in four cases, and 12.5 and 43.4 months after moderate dysplasia (MD) in two cases. The time and BD for the 8 Cis cases were: 18 and 51.7 months after BCH in two cases, 48 months after mD in one case, 4 and 13 months after MD in two cases, and 3.5, 9, and 17.5 months after SD in the other three cases. The time and BD for the four invasive cancer cases were, 13 months after mD in one case, 50 months after MD in another case, and 14 and 19 months after SD in two cases. In addition to natural history observation, we also found sex, age (over 50 vs under 50), family history of upper gastrointestinal cancer, and the presence of multiple esophageal lugol-void lesions to be significant predicators for dysplastic progression; the corresponding OR (95% CI) and P-value were 1.98 (1.14–3.46) and 0.02; 2.32 (1.29–4.19) and 0.004; 1.81 (1.06–3.11) and 0.03; and 4.67 (2.70–8.06) and 0.000 respectively. Conclusions: A 5-year screening interval for BCH and mD, and a 3-year interval for MD, as suggested in China in 2005, may be too long for rapid developing precursors or individuals at high-risk for dysplastic progression. Therefore, shorter intervals should be considered. [Copyright &y& Elsevier]

• The Special Issue addresses the environmental quality in the karst area. • Evaluation of soil loss and change of soil quality in the karst ecosystem. • Water quality change driven by natural factors and agricultural activities. • Assessments of agroecosystem functions in the karst region, southwestern China. The studies in this Special Issue addressed environmental and ecological issues at the karst areas in the Southwest China. The contributions from these studies indicated that some active agricultural practices that were carried out in recent years reduced environmental risk and increased economic benefits at the karst areas. The results of ecosystem service value estimates in recent years showed improvements of ecosystem and environment in karst areas of China. Local farmers and government have realized the importance of protection of environment and ecosystem than before, which might promote to seek sustainable development goal in future. These studies have delivered new knowledgement that addressed the challenges of facilitating environmental sustainability with agricultural development in the karst region of South China. Meanwhile, further research should deepen science advances to improve the resilience of soil and water resources to agricultural practices in the fragile karst ecosystem. [ABSTRACT FROM AUTHOR]

• Agriculture in karst hills is more likely to cause more soil and nutrient losses. • Karst structure might lead to fast nutrient loss and low fertilizer use efficiency. • Results suggest nutrient losses controlled by landform and climate condition. • Carbonate weathering and carbon cycle are strongly impacted by agriculture in karst regions. • Beneficial management practices should be considered for sustainable development. The karst region in southwestern China is a typical region with fragile ecological environments, and the coordination of regional agricultural development and environmental protection faces enormous challenges. Based on the soil and hydrological characteristics of karst in southwestern China, this study summarized water-related environmental issues caused by agricultural activities in this karst region. Agriculture in the karst hills is more likely to cause soil and nutrient losses due to the fast hydrological flow through special karst structures with high permeability. Thus, this review emphasized the impacts of agricultural development on the riverine biogeochemical cycles of elements based on previous studies. Meanwhile, the carbon cycle is also strongly impacted by agricultural activities in this karst region due to enhanced carbonate weathering by nitric acid from the nitrification of ammonium. This weathering mechanism represents a net source of atmospheric CO 2 and might impact regional and global carbon cycling in the Anthropocene. Based on the results summarized in this study, we advocate that in the future, better management of agricultural land, improvement of fertilizer use efficiency, and boosting of nutrient recycling rate should be taken into account for reducing nutrient losses and water quality deterioration. Targeted management of local agricultural practices along with guidance from scientific research results is needed to be devoted to sustainable development of agriculture and economies while protecting water environment. [ABSTRACT FROM AUTHOR]

A tree-ring width chronology (STD) was established using tree-ring cores of Pinus yunnanensis from two sites with different altitudes in Western Yunnan, to study the responses of radial growth to climatic and hydrological factors. The results showed that the radial growth of P. yunnanensis in Western Yunnan was mainly affected by precipitation, temperature and runoff. The radial growth of P. yunnanensis at high altitude (2413.3 m) was controlled primarily by high temperature in summer and runoff in the monsoon season. In contrast, the radial growth of P. yunnanensis at low altitude (1062.6 m) was mainly controlled by precipitation in the growing season and annual runoff. The responses of radial growth of P. yunnanensis at high altitude to temperature change was unstable due to the existence of the temperature threshold. Due to the weakening of the East Asian summer monsoon in the 1980s, the temporal stability of tree growth response at low altitude to precipitation and runoff fluctuated. The radial growth of P. yunnanensis at different altitudes in Western Yunnan was related to the Asian summer monsoon and El Nio-Southern Oscillation.

In this study, 130 surface soil samples were collected at an industrial pollution site in Beijing and the contents of As, Be, Cd, Cu, Cr, Hg, Ni, Pb, Sb, Ti, Zn, and 16 PAHs were determined. The positive matrix factorization (PMF) model was used to analyze the sources of heavy metals and PAHs, and the contributions of these sources to carcinogenic risk and hazard index in the study area were calculated. The results showed that the contents of Cd, Cu, Pb, Hg, As, Zn, and Cr in the soil exceeded the background values in different degrees; Cd, Hg, Pb, Zn, and Cu exceeded the background values by>50%. Low molecular weight PAHs (two and three rings) and high molecular weight PAHs (four to six rings) accounted for 39.6% and 60.4% of the total content of 16 PAHs. The PAH content at 77% of the sampling points at the target site was more than 1000 μg ·kg -1 , which suggests severe PAH pollution at the site. Heavy metals Be, Ti, As, and Ni mainly originated from natural sources. There are three major sources of 7 heavy metals and 16 PAHs at the site: coal combustion (Hg and ∑16PAHs), smelting (Cu, Cr, Pb, and Zn), and traffic (Sb and Cd). The contribution rates of these sources to the total average contents of seven heavy metals and sixteen PAHs at 130 sampling sites were 8.46% (coal combustion), 90.61% (smelting), and 0.94% (traffic). Human health risk assessment results showed that the carcinogenic risk of seven heavy metals and ∑16PAHs ranged from 4.17×10 -6 to 39.38×10 -4 , and the hazard index ranged from 0 to 32.23. The maximum carcinogenic risk and hazard index values were calculated near the coking plant. Benzo[α]pyrene was the PAH that posed the highest carcinogenic risk and Zn was the heavy metal that had the highest hazard index value. The average carcinogenic risk of coal combustion was 2.16×10 -4 , accounting for 50.26% of the total average carcinogenic risk. The average hazard index of smelting was 0.834, accounting for 56.43% of the total average non-carcinogenic risk. These two pollution sources are responsible for the high levels of heavy metals and PAHs in the soil of the steel smelting sites that pose the most severe health risks. The results of this study can provide reference for soil remediation and process optimization at other heavily polluted industrial sites.

To reveal the coupling effect of water and fertilizer on the yield of spring maize under shallow-buried drip irrigation in semi-arid area of western Liaoning, a field experiment was conducted with the quadratic regression orthogonal design of three factors (water, nitrogen and potassium) crossed with five levels in 2017-2018. A quadratic regression model was established with yield (Y) as the dependent variable and irrigation amount (W), nitrogen (N) and potassium (K) application amounts as independent variables to analyze the coupling relationships between Y and W, N and K, respectively. The results showed that the shallow-drip irrigation water-fertilizer coupling had significant impact on yield. The single factor of W, N and K promoted the yield, with their effects ranking as W>N>K. The effect of two-factor interaction on yield increased first and then decreased which ranked as WN>WK>NK. Considering the three-factor coupling effect on yield, the combination of abundant water, nitrogen and potassium was the highest, followed by high water, nitrogen and potassium, and low water, nitrogen and potassium the lowest. As the optimal treatments found by the model, we obtained the suitable water-fertilizer application range of shallow-buried drip irrigation with higher target yield of 8000-8810 kg·hm -2 , that was, the irrigation amount was 43-61 mm, nitrogen 138-343 kg·hm -2 and potassium 79-163 kg·hm -2 under the ambient natural rainfall. The results provided a referable basis for application of water-fertilizer integrated cropping pattern under shallow-buried drip irrigation in semi-arid area of northern China.

Background levels of cadmium (Cd) in carbonate rock areas of Guizhou Province are high. In order to understand the characteristics of Cd in arable soils in these karst areas, the soils in the northern county of Luodian were selected as the study object. By comparing soils in non-karst areas, the distribution characteristics of soil Cd were studied by combining geostatistical analysis and GIS, and the potential ecological risk index and health risk were used to evaluate the potential level of risk to adults and children. The results show that the arable soil Cd content in this karst area is significantly higher than that in non-karst areas ( P <0.05), with a geometric mean of 1.33mg·kg -1 and 0.27 mg·kg -1 , respectively. In comparison, the geometric mean of soil Cd content in forested land in the same areas is 1.57mg·kg -1 and 0.22 mg·kg -1 , respectively. Based on "soil pollution risk control standards", the Cd content of 90% and 22% of arable soil samples was higher than the risk screening value and the risk control value for karst and non-karst areas, respectively. The areas with medium and high Cd values were mainly distributed in the karst areas, presenting medium to strong ecological risks and extremely strong ecological risks, respectively. In contrast, the areas with the lowest Cd concentrations were distributed in the non-karst areas of Jiaoyan, presenting low potential ecological risk. The health risk assessment showed that the non-carcinogenic risk and carcinogenic risk of the three exposure pathways for adults and children in the karst areas are significantly higher than those in the non-karst areas, but the Cd content in the soil does not present non-carcinogenic and carcinogenic risks to local residents. Overall, the problem of Cd pollution in arable soils in the karst area of northern Luodian, Guizhou, is prominent. Therefore, the study of the risks posed by Cd pollution to the soil-plant-human system should be strengthened, and appropriate measures should be taken to prevent and control Cd pollution in the areas at risk.

A quantitative multi-class analytical method covering more than 226 veterinary drugs and other contaminants in muscle, belonging to different drug families, was developed. The method is based on liquid-liquid extraction, purification by low-temperature clean-up and dispersive solid-phase extraction (D-SPE), and analysis was conducted in two analytical runs by column-switching UPLC coupled with electrospray ionisation and tandem mass spectrometry (UPLC-ESI-MS/MS). For most of the target analytes, the optimised pre-treatment processes led to no significant interference from the sample matrix. The limit of quantification varied from 0.05 to 10 µg kg(-1). Statistical evaluation indicated that average recoveries spiked into pork were in the range from 62.4% to 138.8%, and the relative standard deviations were in the range from 2.8% to 26.6% (intra-day precision). The availability of this method will contribute to a better safety assurance of meat with a significant reduction of both effort and time.

Based on the investigation data of damaged vegetations in Karst areas of Guizhou Province during the extreme drought in 2010, an investigation was made on the species composition, floristic composition, life form, leaf characteristics, and environmental conditions of drought-damaged plants at six sampling plots. At these plots, there were 31 plant species drought-damaged, among which, Cunninghamia lanceolata, Celastrus orbiculatus, Rapanea neriifolia, Myrsine semiserrata, Cyclobalanopsis glauca, and Cinnamomum glanduliferum damaged most, and the tropical evergreen arbors with mesophyllous, leathery, and simple leaf suffered more seriously. The damaged plants mainly located on the middle or upper part of steep slopes, and on the thin limestone soils originated from horizontal attitude carbonate rocks. The plants in the microhabitats with soil layer < 30 cm and rock-soil were damaged most, accounting for 87.4% and 40.0% of the total, respectively. It was suggested that the temperate deciduous trees with microphyll could be more planted in Karst areas, and that the microhabitat for the afforestation could be in gully and with thicker soil layer and good site condition.

Environmental health risk of contaminated soil in a typical abandoned industry was analyzed based on the full field investigation according to the site assessment procedure of American Society for Testing and Material (ASTM). Parameters were modified with the combination of Chinese crowd character and site specifics. Results indicated that the site was mainly contaminated with volatile and semi-volatile organic compounds in soil profiles. And the contents of carbon tetrachloride, tetrachloroethylene, pentachloroethane, hexachlorobutadiene, hexachloroethane and hexachlorobenzene in soil samples were exceeded the national environmental standard. These contaminants ranked the carcinogenic risks and hazard quotients more than 10(-2) and 1 in some locations with the exposure by oral ingestion, dermal contact and inhalation. Contaminants in this site had resulted in the high health risks to the residents and surrounding communities. The risk should be reduced to the health acceptable level by the treatment and remediation before further development for residential and commercial utilization.

The aim of the present study was to investigate the association of single nucleotide polymorphisms (SNPs) in matrix metalloproteinase (MMPs) with the risk of gastric cardia adenocarcinoma (GCA) and esophageal squamous cell carcinoma (ESCC). Genotypes were analyzed by polymerase chain reaction-restriction fragment-length polymorphism method in 592 patients and 624 healthy individuals. Significant differences in allele and genotype distributions of MMP-2 -1306C --> T SNP were observed between ESCC and controls (P = 0.02 and 0.01, respectively). Compared with the C/T + T/T genotypes, C/C genotype significantly increased the risk of ESCC (OR = 1.57, 95% CI = 1.10-2.23), especially in individuals in smoker group and in the group with positive family history. The stratification analysis showed there were risk changes of GCA for -735C/C genotype carrier in nonsmoker, for MMP-12 -82G allele and MMP-13 -77A/G genotype carrier in smoker. Our study indicated that these four functional polymorphisms might play roles in developing ESCC and GCA in high incidence region of North China.

We analyzed the responses of delta13 C values of plant leaves to environmental factors (namely, soil water storage, air relative humidity, light intensity, depths of soil, soil organic content, average temperature and soil water content) and the correlations between them, by measuring delta13 C values of leaves for 11 plants species from 4 typical communities with different karst rocky desertification backgrounds in a typical karst catchments basin, Huajiang Gorge. It is revealed that, the delta13 C values and water use efficient of most species decrease with the increasing of water supply; but a few species exhibit an opposite trend and several others exhibit no change in delta13 C values or water use efficiency when these environmental factors varied. Moreover, the correlation analysis indicates that the soil water storage is the leading factor for Pistacia weinmannifolia, Mallotus repandus and Alchornea trewioides, while the depths of soil is essential factor for Nephrolepis cordifolia and Mallotus japonicus var. floccosus, and the light intensity is leading factor for N. cordifolia, Alangium chinense, Broussonetia papyrifera. However, the leading factor for some species like Rapanea kwangsiensis, Sapium rotundifolium and Cipadessa cinerascens are yet not clear, which mean their delta13 C values are affected by more comprehensive factors. Hence it could be concluded that high delta13 C values of leaves could indicate the adaptability of plants for low water regime, high light and low resource environments.

Four different soil particle-size fractions that is clay, silt, fine sand and coarse sand ( <2 microm, 2-20 microm, 20-200 microm, > 200 microm) from the topsoils in an organochlorine pesticide (OCP) field were separated by physical method to characterize the OCPs distribution in soils and to study the effect of organic matter and mineral composition in different separates on pollutants distribution. The results show that the concentrations of HCHs and DDTs in silt with 463.1 mg x kg(-1) and 1225.6 mg x kg(-1) are higher than those in coarse sand, 157.8 mg x kg(-1) and 384.5 mg x kg(-1), respectively. There is a significant correlationship between IgKoc. and the contents of HCHs and DDTs in clay. The analysis on X-ray diffraction of organo-mineral aggregates demonstrates that clay and silt have a much higher content of the clay minerals than those in coarse sand within the contaminated soils. There are some differences with different particle-size fractions in the content and composition of the clay minerals in organo-mineral aggregates, which affect the OCP distribution in soils to some extents. The results also suggest that the distribution of HCHs and DDTs in the particle with more pollutants in the site is similar to that in airborne particles. So the environmental behavior of OCPs in topsoils from the contaminated site should be paid more attention especially in ambient air-soil interaction.

Objective: To analyze the genetic polymorphism of 8 short tandem repeat (STR) loci on human chromosome 2 in Chinese Han population in Shaanxi Province., Methods: Blood samples anticoagulated with EDTA were collected from 176 unrelated Chinese Han individuals in Shaanxi Province. The DNA was extracted for PCR amplification of the relevant fragments, and the amplified products were analyzed using the ABI 3730 Genetic Analyzer., Results: On human chromosome 2, the loci D2S112, D2S162, D2S2330, D2S2216, D2S347, D2S259, D2S319 and D2S168 had 7, 11, 9, 8, 9, 9, 8 and 13 alleles, respectively, with 15, 33, 23, 18, 13, 12, 25 and 33 genotypes for the corresponding alleles. The genotype distribution of all the 8 loci met Hardy-Weinberg equilibrium. The heterozygosities for the 8 STR loci were 0.6985, 0.8274, 0.8042, 0.6816, 0.6541, 0.5213, 0.8432 and 0.8091, with polymorphic information content of 0.6911, 0.8199, 0.7891, 0.6809, 0.6388, 0.5187, 0.8372 and 0.8049, respectively., Conclusion: The 8 loci on chromosome 2 have high heterozygosity and polymorphic information content in Chinese Han population, suggesting their value as useful genetic markers.

Objective: To investigate the possible association of single nucleotide polymorphism (SNP) at the 41657C/T position and 4234G/C position of X-ray repair cross-complementing gene 2 (XRCC2) with susceptibility to esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA) in a population of high incidence region, Ci county and She county of Hebei., Methods: The genotypes of XRCC2 41657C/T and 4234G/C SNPs were detected by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis in 330 ESCC patients, 254 GCA patients and 629 healthy controls., Results: The genotype frequency of XRCC2 41657C/T in ESCC patients (67.8%, 26.4% and 5.8%) was significantly different from that in controls (68.8%, 28.8% and 2.4%; chi square was 7.43, P was 0.02). Compared with CC genotype, TT genotype significantly increased the risk of developing ESCC (OR=2.12, 95%CI: 1.03-4.35). The genotype (59.9%, 35.8% and 4.3%) and allelotype distributions ofXRCC2 41657C/T in GCA patients were significantly different from that in controls (chi square was 7.46 and 7.23, P was 0.02 and 0.01). Compared with CC genotype, CT genotype significantly increased the risk of developing GCA (OR=1.38, 95%CI: 1.01-1.89). The genotype and allelotype distributions of the 4234G/C SNPs in ESCC and GCA patients were not significantly different from that in controls (all P values were above 0.05). Compared with GG genotype, the CG and CC genotype of XRCC2 4234G/C did not show significant effect on the risk of developing ESCC and GCA. When the two XRCC2 SNPs were combined analyzed, the haplotype distribution in GCA patients was significantly different from that in controls (chi square was 13.28, P was less than 0.01). Compared with 41657C/4234G haplotype, 41657C/4234C and 41657T/4234G haplotypes significantly increased the risk of developing GCA (OR were 1.44 and 1.55, 95%CI were 1.06-1.95 and 1.18-2.02, respectively)., Conclusion: In high incidence region of Hebei province, we conclude that XRCC2 41657C/T polymorphism has a potential to be a susceptibility factor for ESCC and GCA while XRCC2 4234G/C polymorphism may not provide a useful marker to predict susceptibility to ESCC and GCA. However, the 41657C/4234C and 41657T/4234G haplotypes might increase the risk of developing GCA.

Objective: To analyze the alterations of serum proteomic pattern in esophageal squamous cell carcinoma (ESCC) by SELDI-TOF-MS, to establish a diagnostic model of ESCC screening in high incidence area and investigate its clinical value., Methods: SELDI-TOF-MS and CM10 proteinChip were used to detect the serum proteomic patterns of 36 cases of ESCC and 38 healthy control subjects in high incidence area. The data were analyzed and a diagnostic model was established by using support vector machine (SVM). The diagnostic model was evaluated by leave-one-out cross validation., Results: At the molecular weight range of 2000 to 20,000, 31 protein peaks were significantly different between ESCC and controls (P < 0.01). A diagnostic model consisting of 4 protein peaks could do the best in diagnosis of ESCC and controls. The accuracy was 85.1%, sensitivity was 86.1%, specificity was 84.2%, and positive value was 83.8%., Conclusion: The diagnostic model formed by 4 protein peaks, established in this study, can well distinguish ESCC from healthy subjects. It provides a new approach for ESCC screening in high incidence area.

The characteristics of environmental geochemistry of heavy metal pollutant cadmium (Cd) in the surficial soil of Guiyang, Guizhou, China was studied. The baseline concentration of Cd in soil and the geochemistry norms have been established to distinguish the nature or artificial influence on the environment. The statistical analysis indicated that the baseline of Cd in Guiyang was 0.068 mg/kg. Geoaccumulation index analysis indicated that the unpolluted surface soils accounts for 40%, and 19% between nonpollution to mid-pollution, 14% for mid-pollution, 19% between mid-pollution to severe pollution, 7% for severe pollution, only 1% between severe pollution to super severe pollution. The maximum of Cd contamination degree (CD) is 12.1. CD analysis indicated that the unpolluted surface soils accounts for 57.9%.

Objective: To evaluate the fast serum pepsinogen level of the healthy adults among local population in areas with high incidence of gastric cancer and to study the suitable cut-off values of serum pepsinogen abnormality for the screen of chronic atrophic gastritis (CAG) and gastric carcinoma (GC) in China., Methods: Serum PG I and PG II levels were detected with time resolved fluorescence immunoassay (TRFIA). The fast serum PG I and PG I level as well as PG I/PG II ratio of 606 healthy adult residents among local population in Zanhuang county, Hebei province were detected and the normal distribution ranges determined. The relationship between different cut-off values of serum PG I level, PG I/PG II ratio and corresponding pathological changes in gastric mucosae were comparatively analyzed with serum PG detection, endoscopic biopsy and pathological observation in 720 cases of local residents receiving endoscopic examination in the high incidence area of gastric cancer. The efficacy, sensitivity and specificity of different PG I, PG II abnormality cut-off values in the screen p rogram of CAG and GC were statistically analyzed., Results: The serum PG I, PG II and PG I/PG II ratio levels of healthy adults from a local natural population in the high incidence area of gastric cancer were all skewed from normal distribution. The median level of PG I, PG II and PG I/PG II were 161 microg/L, 14.8 microg/L and 10.5 respectively. Data from comparative studies on serum PG level and pathological changes of gastric mucosae showed that within the serum PG I range from 40 microg/L to 80 microg/L and PG I/PG II ratio range from 3 to 8, sensitivity of the screening program for CAG and GC increased while the specificity decreased along with the increase of cutoff values of serum PG I and PG I/PG II ratio. Results from statistical receiver operator characteristic curve (ROC) analysis suggested that the best cut-off value of PG I and PG I/PG II abnormality for the screening of CAG and GC being PG I < or =60 microg/L,PG I/PG II < or =6 respectively., Conclusion: The serum PC I, PG II and PG I/PG II ratio levels of healthy adults from a local natural population in the high incidence area of gastric cancer were all skewed from normal distribution. Serum PG I < or =60 microg/L and PG I/PG II ratio < or =6 as abnormal cut-off value for the screen of CAG and GC could result relatively good sensitivity and specificity.

Objective: To analyze the allele frequencies of 6 STR loci (D12S358, D12S1675, D12S1663, D12S1697, D12S16725 and D12S1613) on chromosome 12 among KBD patients and residents in the KBD and non-KBD areas., Methods: EDTA-blood samples were collected from 146 unrelated Chinese Han individuals in Shaanxi Province including 57 KBD patients, 48 control subjects living in the Kashing-Beck disease(KBD) area and 48 in the non-KBD area. The DNA samples were extracted and amplified by PCR, and the PCR products were analyzed by ABI 3100 Genetic Analyzer., Results: In KBD patients, the allele number for the 6 STR loci (D12S358, D12S1675, D12S1663, D12S1697, D12S16725 and D12S1613) was 7, 7, 7, 10, 12 and 8, and the genotype number were 13, 12, 9, 17, 19 and 10, respectively; in the residents in KBD area, the allele number was 7, 5, 7, 9, 13 and 9, and the genotype number 12, 10, 12, 19, 16 and 8; in residents in non-KBD area, the allele number was 7, 5, 5, 12, 8 and 9, and the genotype number 17, 16, 8, 22, 14 and 8. There were significant differences in the allele frequencies in the D12S1725 loci between KBD patients and residents living in KBD area (P=0.0119) and the non-KBD area (P=0.0050), but no significant difference in other 5 loci among the 3 groups., Conclusion: KBD patients have significantly different allele distribution patterns in the D12S1725 loci from the control subjects.

Aim: To investigate the possible association of microsomal epoxide hydrolase (mEH) Tyr113His polymorphism with susceptibility to esophageal squamous cell carcinoma (ESCC) in a population of North China., Methods: The mEH Tyr113His genotypes were determined by polymerase-chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis in 257 patients with esophageal squamous cell carcinoma (ESCC) and 252 healthy subjects as a control group., Results: The frequencies for Tyr and His alleles were 44.2%, 55.8% in ESCC patients, and 44.0% and 56.0% in healthy subjects, respectively. No statistic difference in allele distribution was observed between ESCC patients and controls (chi2=0.008, P=0.929). The overall genotype distribution difference was not observed between cancer cases and controls (chi2=2.116, P=0.347). Compared with Tyr/Tyr genotype, neither His/His genotype nor in combination with Tyr/His genotype significantly modified the risk of the development of ESCC, the adjusted odds ratio was 1.076 (95% CI=0.850-1.361) and 0.756 (95% CI=0.493-1.157), respectively. When stratified for sex, age, smoking status and family history of upper gastrointestinal cancer, His/His genotype alone or in combination with Tyr/His genotype also did not show any significant influence on the risk of developing ESCC., Conclusion: MEH Tyr113His polymorphism may not be used as a stratification marker in screening individuals at a high risk of ESCC.

Aim: To investigate the association of the NQO1 (C609T) polymorphism with susceptibility to esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA) in North China., Methods: The NQO1 C609T genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in 317 cancer patients (193 ESCC and 124 GCA) and 165 unrelated healthy controls., Results: The NQO1 C609T C/C, C/T and T/T genotype frequency among healthy controls was 31.5 %, 52.1 % and 16.4 % respectively. The NQO1 T/T genotype frequency among ESCC patients (25.9 %) was significantly higher than that among healthy controls (chi(2)=4.79, P=0.028). The NQO1 T/T genotype significantly increased the risk for developing ESCC compared with the combination of C/C and C/T genotypes, with an age, sex and smoking status adjusted odds ratio (OR) of 1.78 (1.04-2.98). This increased susceptibility was pronounced in ESCC patients with family histories of upper gastrointestinal cancers (UGIC) (adjusted OR=2.20, 95 % CI=1.18-3.98). Similarly, the susceptibility of the NQO1 T/T genotype to GCA development was also observed among patients with family histories of UGIC, with an adjusted odds ratio of 2.55 (95 % CI=1.21-5.23), whereas no difference in NQO1 genotype distribution was shown among patients without family histories of UGIC., Conclusion: Determination of the NQO1 C609T genotype may be used as a stratification marker to predicate the individuals at high risk for developing ESCC and GCA in North China.