Investigation of radon and heavy metals in Xuanwei and Fuyuan, high lung cancer incidence areas in China.

Xuanwei and Fuyuan, two counties located in southwest China, are areas with known high lung cancer incidence. Pollution relative to coal combustion, especially serious air pollution generated by burning smoky coals in unvented households, has been thought to be the most predominant cause. Possible inorganic carcinogenic matter including radon in air and arsenic, lead, chromium, cadmium, nickel, and beryllium in water, soil, and coal were sampled and examined to find the current pollution status, distributions, characteristics, and relationships to the lung cancer incidence. The concentrations of mercury in air of Xuanwei and Fuyuan ranged from 1.7 to 205.3 ng/m3 (indoor), 1.3 to 7.5 ng/m3 (ambient). No radon concentration exceeded the World Health Organization standard. Results indicated that household stove improvement by changing stoves from unvented to vented obviously alleviated the indoor air pollution of carcinogenic metals. Most of the carcinogenic metals were also found at very low levels in water and soil, which therefore had little influence on human health. Concentrations of these elements at different sites did not vary in any relation to lung cancer incidence. The study described in this article added basic data; the results of the authors' study will be helpful in determining pollution status and to future studies on the etiology of lung cancer.

[Determination of 82 polychlorinated biphenyls in biological samples using accelerated solvent extraction-isotope dilution-high resolution gas chromatography-high resolution mass spectrometry].

In China, the detection methods for polychlorinated biphenyls (PCBs) in aquatic products are mainly effective for 6 indicative PCBs and 12 coplanar dioxin-like PCBs, which only account for a limited proportion of PCBs in organisms. In this study, to obtain the detailed concentration levels of PCBs in organisms, elucidate the metabolism and enrichment characteristics of PCBs in organisms, and accurately evaluate the exposure level and risks of PCBs to humans, an improved method for the simultaneous determination of 82 PCBs in fish and shellfish samples was developed using isotope dilution-high resolution gas chromatography-high resolution mass spectrometry (ID-HRGC-HRMS). The recovery and reproducibility of two extraction methods, i. e., oscillatory extraction and accelerated solvent extraction (ASE), were compared. Finally, ASE was chosen for subsequent experiments. Specifically, after adding 1 ng13C-labeled extraction internal standards, the samples were extracted under pressure by ASE using a mixture of n-hexane-dichloromethane (1∶1, v/v). The experimental conditions employed for this were a pressure of 10.3 MPa, heating temperature of 100 ℃, heating time of 5 min, static time of 8 min, flush volume of 60%, purging time of 120 s, and 34 mL cells. Subsequently, the extracts were loaded on an 8 g acid silica gel (44%) column (inner diameter: 15 mm) and eluted with 90 mL of n-hexane. After purification and concentration, the analytes were determined by HRGC-HRMS with a fused-silica capillary column (DB-5MS, 60 m×0.25 mm×0.25 µm). The temperature program was optimized to separate the most target compounds at the baseline. Specifically, the initial oven temperature was 120 ℃, which was held for 1 min, following by heating to 180 ℃ at 30 ℃/min, heating to 210 ℃ at 2 ℃/min and holding for 1 min, and further heating to 310 ℃ at 2.5 ℃/min and holding for 1 min. The injector and ion source temperatures were 270 ℃ and 280 ℃, respectively. With a static resolution of 10000, the HRMS instrument was operated in the selected-ion monitoring mode at an electron energy of 35 eV. The 82 PCBs were qualified by their retention time and two characteristic ions, and thereafter quantified using the mean relative corresponding factor (RRF). The results showed that the relative standard deviation (RSD) of the RRF obtained from six-point calibration standard solutions was less than 20%. The linearity ranges were from 0.1 to 200 µg/L, and the correlation coefficients (r2) were greater than 0.99. Under optimum conditions, the method detection limits (MDLs) for the PCBs of biological samples were in the range of 0.02-3 pg/g. To validate the method, the fish and shellfish samples were spiked with a low level (0.4 ng) and high level (3.6 ng) of native PCB standards. The spiked recoveries using low-concentration native PCBs were 71.3%-139% in fish and 76.9%-143% in shellfish, and the RSDs (n=7) were 2.1%-14% and 4.5%-14%, respectively. The spiked recoveries using high-concentration native PCBs were 77.6%-141% and 82.2%-131%, respectively, and the RSDs (n=7) were 1.4%-9.4% and 1.7%-11%, respectively. An analysis of fresh fish and shellfish samples showed that the contents of a single PCB ranged from "not detected" to 54.1 pg/g, where 12 coplanar dioxin-like PCBs were detected in the range of 12.6 pg/g to 74.5 pg/g, six indicative PCBs in the range of 30.9 pg/g to 62.1 pg/g, and 82 PCBs in the range of 174 pg/g to 672 pg/g. It was concluded that this method could be successfully applied for the determination of PCBs in biological samples with good accuracy and precision. This comprehensive analytical method of PCBs in aquatic products provides effective technical support for biological monitoring; it will also aid in ecological and environmental management and the implementation of the Stockholm Convention policies.

Quantitation of ultra-trace nitrated polycyclic aromatic hydrocarbons isomers in water by online solid-phase extraction coupled-liquid chromatography-mass spectrometry.

An online solid-phase extraction (SPE)-coupled liquid chromatography-mass spectrometry (LC-MS) method was established for the determination of 10 nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) in water. Water samples were mixed with methanol to generate 40% methanol solutions (v/v), and filtered by 0.45 µm membrane. The filtration with polytetrafluoroethylene(PTFE) membrane got higher recovery rates than nylon membrane, especially for 4-ring and 5-ring nitro-PAHs. 2.5 mL solution was directly injected into online SPE flow path to allow for online purification and enrichment of target analytes in the SPE column. The nitro-PAHs eluted from the SPE column were automatically transferred to the analytical flow path by a well-designed valve-switching system. With the optimization of LC and MS condition, ten nitro-PAH isomers was separated and detected from each other by LC-MS/MS with negative atmospheric pressure chemical ionization (APCI). It was firstly found that nitro-PAHs could produce strong [M-H]- precursor ions in the primary MS besides [M+e]- and [M+15]-. In the secondary MS, the precursor ions mainly lose NO neutral molecule (30 Daltons) to produce daughter ions. The online SPE and LC-MS analysis process was completed in 15.5 min. The linear correlation coefficients of 10 nitro-PAH standard curves were higher than 0.99. The detection limits of nitro-PAHs were about 1.2~22.2 ng/L (S/N=3). The intra-day and inter-day reproducibility (RSD, n=6) were 1.6%~8.4% and 5.3%~16.9%, respectively. The recoveries of 10, 40 and 200 ng/L in tap water were 71.7%~106.4%, 79.7%~100.9% and 73.0%~105.5%, with the corresponding RSD of 2.4%~10.5%, 2.1%~8.6% and 2.7%~6.2%, respectively.

Investigations on boron levels in drinking water sources in China.

To evaluate boron contamination of public drinking water in China, both dissolved and total boron contents in 98 public drinking water sources from 49 cities, 42 brands of bottled water samples from supermarkets in several cities, and 58 water samples from boron industrial area were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Our experimental results showed that boron existed in public drinking water sources mainly in dissolved status with total concentrations ranging from 0.003 to 0.337 mg/L (mean = 0.046 mg/L). The mean boron concentrations in mineral and pure bottled water were 0.052 and 0.028 mg/L, respectively. The results obtained in this work showed that there was no health risk on view of boron in public drinking water sources and bottled water. In boron industrial area, boron concentrations in surface water and ground water were 1.28 mg/L (range = 0.007-3.8 mg/L) and 18.3 mg/L (range = 0.015-140 mg/L), respectively, which indicated that boron industry caused boron pollution in local water system.

Level, Source, and Spatial Distribution of Potentially Toxic Elements in Agricultural Soil of Typical Mining Areas in Xiangjiang River Basin, Hunan Province.

The concentrations, chemical availability, distribution, and sources of potentially toxic elements (PTEs) in the soil of Xiangjiang Basin in Hunan Province, China were investigated at 85 sites. The highest mean concentrations of Cd, Cu, Zn, As, and Pb were observed in Hengyang, whereas those for Mn, Co, and Hg were observed in Changde. The pollution index values followed the order: Cd > Hg > Cu > Zn > As > Pb; the mean geo-accumulation index values were in the order: Cd > Hg > Pb > Cu > Zn > As > Co > Mn. Cd was associated with moderate contaminated level, Hg and Pb were associated with moderate contaminated to uncontaminated level, and Cu, Zn, As, Co, and Mn were associated with uncontaminated level of pollution. Furthermore, 64.5% of Cd was water-soluble and exhibited exchangeable fractions; its chemical availability posed a risk to the ecosystem. Spatial analysis, principal component analysis, and a positive matrix factorization model were used to assess the PTE sources. Four principal components contributed to 88.8% of the 8 PTEs concentrations. Mining, smelting, industrial, and agricultural activities, alongside sewage irrigation, the use of agrochemicals, and vehicular emissions are the possible anthropogenic sources that pollute agricultural products and threaten human health in the Xiangjiang Basin.

Indoor and outdoor air pollution of polycyclic aromatic hydrocarbons (PAHs) in Xuanwei and Fuyuan, China.

Xuanwei and Fuyuan, located in the Yunnan province in southwest of China, are known to have a high incidence of lung cancer caused by indoor airborne polycyclic aromatic hydrocarbons (PAHs) generated during bituminous coal combustion for heating and cooking in unvented households. In this study, indoor and outdoor air was sampled at 38 sampling sites around these areas in January 2007. The concentrations of 16 PAHs were analyzed. The sources of PAHs in these two counties were also investigated. Quartz filters and polyurethane foam were used to collect particle-bound PAHs (p-PAHs) and gas-phase PAHs (g-PAHs), respectively. The concentrations of benzo(a)pyrene (Bap), the best index for PAHs carcinogenicity, were higher in indoor air than that in outdoor air. Bap levels in all the indoor air samples were higher than the national criteria (1.0 ng m(-3)) in China, but were much lower than those in previous studies in the same areas. Bap levels in 20 out of the 29 outdoor air samples were higher than the national criteria (10 ng m(-3)) of China. Significant differences in the gas/particle partition of PAHs were found between the indoor and the outdoor air samples. Principal component analysis (PCA) in combination with diagnostic ratios indicated that coal combustion was the predominant source for both indoor and outdoor PAHs pollution.

[Soil heavy metal cadmium standard limit and range of background value research].

With the rapid development of industrial and agricultural production in China, problems such as excessive soil pollutants worsen year by year, and soil cadmium pollution resulting from the emergence of "cadmium rice" and other food security incidents occur frequently. It causes the extensive concern of society on soil cadmium environmental standards. A soil environmental standard is the foundation for the evaluation of soil environmental quality. The maximum allowable value of cadmium that affects plant and animal and human health is regarded as the basis value all over the world; however, the certification methods and the goals of standard application are different, thus the standard limit has a great difference. Through the research on domestic and foreign soil cadmium standard limits and the soil cadmium background values in China, the soil cadmium background content range values of the provinces and of some types of soil are given. We report the outstanding problems existing in China's current environmental quality standard of soil cadmium. It is proposed that the soil environmental quality standard should allow the coexistence of gradient of soil cadmium standard limit, effective state and total standard limit, and anthropogenic pollution and background values exceeding the standard should be strictly distinguished.

[Determination of five microcystins in water using liquid chromatography-diode array detection/ion trap mass spectrometry].

A method for the determination of five microcystins (MCs) in water was established using liquid chromatography (LC)-diode array detection (DAD)/ion trap mass spectrometry (IT MS). The five MCs in water were enriched and purified by solid phase extraction, and determined by LC-DAD/IT MS. DAD was used for both qualitative and quantitative analysis, and IT MS was used for qualitative analysis only. Under the optimized conditions, the detection limits of 5 MCs in water were 0.1 microg/L. The average recoveries of the three spiked levels (0.2, 0.8 and 5 microg/L) were 52.2% - 115.2% with the relative standard deviations (RSDs) of 1.2% - 10.0%. This method uses UV absorption spectrum and MS spectrum in the qualitative and quantitative analysis, and can be applied in the determination of various MCs in both surface water and drinking water.

[Determination of atrazine and its metabolites in human urines using gas chromatography].

Atrazine (ATZ) was widely used to control broadleaf weeds. Numerous animal experiments have proved that atrazine is a suspicious endocrine disruptor. Thus, further development of the ability to estimate low-dose human exposure to atrazine is requested in epidemiologic studies to correlate the toxicological effects associated with the concentrations of ATZ and its metabolites in human body. A method for detecting ATZ and its metabolites (deethylatrazine (DEA), deisopropylatrazine (DIA), deethyldeisopropylatrazine (DEDIA)) in human urines using gas chromatography was established. A urine sample was extracted by ethyl acetate, and purified using a Florisil column. Final concentrated extract was analyzed by a gas chromatograph-electron capture detector. The conditions of this method were optimized. The limits of detection were 0. 002 5 mg/L for DEDIA, 0. 005 mg/L for DEA, DIA and ATZ. The linear ranges were from 0.2 to 8 ng for all analytes. The atrazine concentrations in urine samples of the workers collected from an atrazine plant were determined by this method. The concentration ranges were 0.003 -0.301 mg/L for DEDIA, 0.005 -0.011 mg/L for DEA, 0.006 -0.276 mg/L for DIA, and 0.005 -0.012 mg/L for ATZ.