Evaluation of Polycyclic Aromatic Hydrocarbons (PAHs) in Bamboo Shoots from Soil.

The toxicity, carcinogenicity and persistence of polycyclic aromatic hydrocarbons (PAHs) pose a great threat to the ecological system and human health. The contamination levels, translocation and source analysis of 16 PAHs in bamboo shoot and its planted soil were investigated. The average concentrations of total PAHs were 18.80 ± 1.90 µg/kg and 123.98 ± 113.36 µg/kg in bamboo shoots and soils, respectively. The most abundant PAH was Phenanthrene (PHE), with the detected average concentrations of 5.85 µg/kg in bamboo shoots and 19.28 µg/kg in soils. The highest detected types of PAHs were 3 rings and 4 rings, with the proportions of 80.69% (bamboo shoots) and 35.23% (soils). The transfer factors of PAHs were ranged from 0.011 to 0.895, in which PAHs with 3 rings showed the strongest transfer ability. The combustion of biomass and petroleum might be the main source of PAHs in the planted soils of bamboo shoots.

Characterization of iron walnut in different regions of China based on phytochemical composition.

Little is known about the phytochemical composition of iron walnuts. Differences in the geographical origin of iron walnuts associated with economic benefits should also be examined. In this study, the phytochemical composition (fatty acids, Vitamin E, total polyphenols and flavonoids, amino acids, and minerals) of iron walnuts in China was investigated. The results showed that there were significant differences (p < 0.05) in the phytochemical composition of iron walnut oils and flours from different regions. Positive (r > 0.5, p < 0.05) and negative (r < - 0.5, p < 0.05) correlations were found between amino acids/minerals and amino acids/oleic acid, with the highest correlation coefficient (r = 0.742, p < 0.05) between Cu and tyrosine. In addition, based on the 12 phytochemical fingerprints selected by random forest, a geographical-origin identification model for iron walnuts was established, with a corresponding correct classification rate of 96.6%. The top three phytochemical fingerprints for the geographical-origin identification of iron walnut were microelements, macroelements, and antioxidant composition, with contribution rates of 61.7%, 18.1%, and 9.9%, respectively.

Evaluation of risk levels of trace elements in walnuts from China and their influence factors: Planting area and cultivar.

The potential health risk of trace elements in nut foods has been widely concerned. The accumulations of trace elements by plants in the environment are disturbed by multiple factors. The objective of this work was to investigate the risk levels of trace elements in walnuts and their influence factors (planting area and cultivar). A total of 228 walnut samples were collected from four major walnut producing areas of China. The contents of essential elements for Fe, Cu, Zn, Mo and Se were 35.8, 21.9, 14.8, 0.3 and 0.04 mg/kg, respectively. The contribution of Cu for dietary reference intake was as high as 82.22%. The risk levels of potential toxicological elements and toxic elements within the acceptable limits. Significantly, the hazard quotients (HQs) of Ba and Co were up to 26.14% and 25.31%, respectively. The effect of planting area on trace elements was determined from the aspects of regional distribution and urbanization. Significant differences of essential elements were found between northeast and northwest areas. The urbanization directly influenced toxic elements, which could cause variation up to 85.0% (Pb) and 42.9% (As). Finally, cultivar effect was confirmed that all walnut cultivars were divided into four categories with different trace element characteristics.

Risk assessment and prediction for toxic heavy metals in chestnut and growth soil from China.

BACKGROUND: Toxic heavy metals (THMs) cause severe environmental hazards and threaten human health through various consumption of food stuff. However, little is known of THMs in chestnuts. In this study, the risk assessment and prediction of THMs [lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd) and mercury (Hg)] in chestnuts and growth soils from China were investigated. RESULTS: The main detected THMs in chestnuts and growth soils were As and Cd. The total pollution levels of the five THMs (Nemerow pollution indexes, NPIs) were 0.062 and 1.06, respectively. The dietary risks for children were higher than those of adults, especially short-term non-carcinogenic risk. The main combined risks from the relationships between THMs were Pb-Cr (r = 0.85, P < 0.01) in chestnuts and Pb-As (r = 0.59, P < 0.01) in growth soils. The risk source was found to be the uptake effect of THMs from soil to chestnut, with the highest bioaccumulation factors (BCFs) of Cd (0.254). Several comprehensive risk models were established with the highest coefficient of determination (R2 ) of 0.79. In addition, the main contribution rates of different soil parameters to comprehensive risk of THMs uptake were 49.8% (Cd), 23.4% (pH), 13.8% (Cr) and 13.0% (organic carbon). CONCLUSION: The total pollution levels of THMs fell outside of the safety domain in growth soils. Furthermore, more attention needs to be paid to Cd pollution owing to its low environment background value and high accumulation ability. Three main soil parameters (Cr content, pH, organic carbon) played important roles in the formations and accumulations of THMs in chestnuts. © 2019 Society of Chemical Industry.

Distribution, traceability, and risk assessment of organophosphate flame retardants in agricultural soils along the Yangtze River Delta in China.

Severe pollution threatens the ecosystem and human health in the Yangtze River Delta (YRD) in China because of the rapid development of industry in this area. This study examines the types, distribution, concentration, and origin of fourteen typical organophosphate flame retardants (OPFRs) in agricultural soils within the YRD region to offer insights for pollutant control and policy-making. The total concentration of OPFRs (ΣOPFRs) varied between 79.19 and 699.58 µg/kg dry weight (dw), averaging at 209.61 µg/kg dw. Among the OPFRs detected, tributoxyethyl phosphate (TBEP) was identified as the main congener, followed by tri-n-butyl phosphate (TnBP), tris(2-chloroisopropyl) phosphate (TCPP), and trimethyl phosphate (TMP). Source analysis, conducted through correlation coefficients and PCA, indicated that OPFRs in agricultural soils within the YRD region mainly originate from emissions related to plastic products and transportation. The health risk exposure to ΣOPFRs in agricultural soil was considered negligible for farmers, with values below 1.24 × 10-2 and 1.76 × 10-9 for noncarcinogenic and carcinogenic risks, respectively. However, the ecological risk of ΣOPFRs in all the samples ranged from 0.08-1.08, indicating a medium to high risk level. The results offer a comprehensive understanding of OPFR pollution in agricultural soils in the YRD region and can be useful for pollution control that mitigates ecological and health risks in this region.

Prediction of BTEX volatilization in polluted soil based on the sorption potential energy theory.

Initial volatile concentration (Cs0) is a crucial parameter for the migration and diffusion of volatile organic pollutants (VOCs) from the soil to the atmosphere. The acquisition of Cs0 is, however, time-consuming and labor-intensive. This study developed a prediction model for Cs0 based on theoretical analysis and experimental simulations. The model was established by correlating the molecular kinetic and sorption potential energy. The pore structure and pore size distribution of the soil were analyzed based on the fractal theory of porous media, followed by calculating the sorption potential energy corresponding to each pore size. It was observed that the pore size distribution of soil influenced BTEX (benzene, toluene, ethylbenzene, and xylene) volatilization by impacting sorption potential energy. The soil parameters, such as organic matter and soil moisture content, and the initial concentration and physical properties of BTEX were coupled to the prediction model to ensure its practicability. Red soil was finally used to verify the accuracy and applicability of the model. The experimental and predicted values' maximum relative and root-mean-square errors were determined to be 24.2% and 11.7%, respectively. The model provides a simple, rapid, and accurate assessment of soil vapor emission content due to BTEX contamination. This study offers an economical and practical method for quantifying the amount of volatile BTEX in contaminated sites, providing a reference for its monitoring, control, and subsequent remediation.

Improvements on Gaussian mixture model and its application in identifying aerosol types in two major cities in the Yangtze River Delta, China.

Accurately identifying the authentic local aerosol types is one of the fundamental tasks in studying aerosol radiative effects and model assessment. In this paper, improvements were made to the traditional Gaussian Mixture Model, leading to the following results: 1) This study introduces several improvements to the traditional Gaussian Mixture Model (GMM), referred to as M-GMMs. These improvements include the incorporation of multivariate kurtosis coefficients, Mahalanobis distance instead of Euclidean distance, and weights of variables. The M-GMMs overcome the issues related to dimensional units and correlations among multiple parameters, thereby enhancing the estimation of the covariance matrix. 2) The proposed M-GMMs model was evaluated for its clustering performance using machine-generated data with known classifications and real iris flower data. The results demonstrated that the classification performance of M-GMMs was superior to other models. Furthermore, compared to the slightly less effective K-means algorithm (which requires manual definition of the number of aerosol types), the M-GMMs model was able to automatically iterate and produce consistent classification results based on similar characteristics. 3) There is still a significant disparity between the characteristics of real stations and typical aerosols. Directly evaluating local aerosols using the characteristics of typical aerosols results in substantial errors. However, the M-GMMs model can effectively reflect the authentic aerosol characteristics at the local level. 4) The M-GMMs model was utilized to perform cluster analysis on the Xuzhou and Nanjing stations of AERONET. This analysis yielded quantitative proportions, temporal distribution characteristics, and spectral distribution features of aerosol types in the two regions. The improved M-GMMs model presented in this paper enables more accurate and continuous characterization of aerosol type variations. Its findings hold significant theoretical and practical value in reassessing aerosol radiative effects.

Selective ion migration in a polyelectrolyte driving a high-performance flexible moisture-electric generator.

We propose a novel moisture-electric generator that utilizes the unique properties of a blended poly(4-styrene sulfonic acid) and poly(vinyl alcohol) with phytic acid by screen printing and scrape coating, achieving an impressive open-circuit voltage of 0.88 V from ambient humidity. This innovative design significantly enhances ion transport, moisture adsorption, and flexibility, making a marked improvement in converting environmental humidity to electrical energy.

Nanofluid-Guided Janus Membrane for High-Efficiency Electricity Generation from Water Evaporation.

Harvesting electricity from widespread water evaporation provides an alternative route to cleaner power generation technology. However, current evaporation power generation (EPG) mainly depends on the dissociation process of certain functional groups (e.g., SO3H) in water, which suffers from low power density and short-term output. Herein, the Janus membrane is prepared by combining nanofluid and water-grabbing material for EPG, where the nanoconfined ionic liquids (NCILs) serve as ion sources instead of the functional groups. Benefiting from the selective and fast transport of anions in NCILs, such EPG demonstrates excellent power performance with a voltage of 0.63 V, a short-circuit current of 140 µA, and a maximum power density of 16.55 µW cm-2 while operating for at least 180 h consistently. Molecular dynamics (MD) simulation and surface potential analysis reveal the molecular mechanism, that is, the diffusion of Cl- anions during evaporation is much faster than that of cations, generating the voltage and current across the membrane. Furthermore, the device performs well in varying environmental conditions, including different water temperatures and sources of evaporating water, showcasing its adaptability and integrability. Overall, the nanofluid-guided Janus membrane can efficiently transform low-grade thermal energy in evaporation into electricity, showing a competitive advantage over other sustainable applied approaches.

Predicting soil concentrations and remediation target values of BTEX by an off-gas based mass transfer model.

Soil vapor extraction (SVE) is a widely used technology for the remediation of volatile organic compounds (VOCs) contaminated soils. Residual concentrations of VOCs are crucial for assessing the SVE process and planning when to stop this process, however, the measurement of their residual concentrations in the soil is complicated. Herein, a pseudo-first-order sequential reaction model was established to predict the mass transfer of the BTEX (benzene, toluene, ethylbenzene, xylene) between the soil and off-gas during the SVE process. Based on this mass transfer model, the residual concentrations of BTEX in the soil during the trailing stage could be accurately estimated (R2 > 0.89) by their off-gas concentrations that were directly monitored in real time. Considering the removal efficiency and operating costs, a concept of the remediation target values (RTV) was proposed for the SVE technology, and its relevant model (R2 > 0.92, NRMSE = 6.4-16.8 %) was established based on the experimental data. The remediation endpoint can be further estimated based on the RTV with an overall accuracy of 84-100 %. These findings provide a simple and fast way to predict VOC concentrations in soil with easy-to-know factors and online monitoring of off-gas concentrations and will guide and optimize the SVE process toward more economical and efficient techniques for soil remediation.

Aerosol structure and vertical distribution in a multi-source dust region.

The vertical distribution of aerosols was directly observed under various atmospheric conditions in the free troposphere using surface micro-pulse lidar (MPL4) at the Zhangye Station (39.08 degrees N, 100.27 degrees E) in western China in the spring of 2008. The study shows that the aerosol distribution over Zhangye can be vertically classified into upper, middle and lower layers with altitudes of 4.5 to 9 km, 2.5 to 4.5 km, and less than 2.5 km, respectively. The aerosol in the upper layer originated from the external sources at higher altitude regions, from far desert regions upwind of Zhangye or transported from higher atmospheric layers by free convection, and the altitude of this aerosol layer decreased with time; the aerosols in the middle and lower layers originated from both external and local sources. The aerosol extinction coefficients in the upper and lower layers decreased with altitude, whereas the coefficient in the middle layer changed only slightly, which suggests that aerosol mixing occurs in the middle layer. The distribution of aerosols with altitude has three features: a single peak that forms under stable atmospheric conditions, an exponential decrease with altitude that occurs under unstable atmospheric conditions, and slight change in the mixed layer. Due to the impact of the top of the atmospheric boundary layer, the diurnal variation in the aerosol extinction coefficient has a single peak, which is higher in the afternoon and lower in the morning.

A new theoretical model deriving planetary boundary layer height in desert regions and its application on dust devil emissions.

Planetary boundary layer height (PBLH) is one of the major factors influencing the occurrence of dust storms and dust devils in desert regions; however, the existing planetary boundary layer parameterization schemes are largely limited to reflect the actual diurnal cycles of PBLH in desert regions, which further affects the global dust-aerosol emission evaluation. A new theoretical model deriving PBLH applicable to the desert areas is developed based on heating effect of dust aerosols and the method calculating PBLH by the vertical profile of virtual potential temperature, and then parameterized by observations at the desert regions in northern China (defined as new PBLH scheme). The results show that the simulated PBLH by the new scheme agrees better with the observations compared to the available PBLH schemes in the WRF model, such as Yonsei University scheme (YSU), Asymmetric Convection Model 2 scheme and Shin-Hong scale-aware scheme. The PBLHs derived from those three schemes might be replaceable by the new scheme due to the great improvement. The normally used YSU scheme and the new PBLH scheme are further applied to evaluate dust-devil emissions, despite the consistent unimodal distribution and similar spatial distribution in daily dust-devil emissions from two schemes in comparison with the measured occurrence frequency of dust devils, the new PBLH scheme improves the emission at the episodes from 09:00 to 18:00 LST (Local Standard Time) with greater magnitude relative to the YSU scheme, and demonstrates more significant differences near the peak-emission time, leading to approximate 1.5 times higher in the summer emission of dust devils. The results imply that the existing schemes underestimate about 5% of the contribution of dust devil emissions to the total amount of dust aerosols, and the new scheme can evaluate better, and provide new insight to understand the impact of the aerosol on climate effect.

Integrative investigation of dust emissions by dust storms and dust devils in North Africa.

Dust aerosols in North Africa account for >50% of the global total; however dust emission areas are still unclear. Based on the analysis of dust storms simulated with the numerical Weather Research and Forecast (WRF) model, satellite aerosol index (AI), and the dust data observed at 300 meteorological stations over 20 years, the spatio-temporal distribution characteristics of dust storm, dust devil and AI are compared and analyzed. The results show that: 1) There are two dust emission mechanisms: the dynamically-dominated dust storm and thermally-dominated dust devil; 2) Dust storms occur most frequently in Spring and are concentrated in the areas of Grand Erg Occidental Desert to the Erg Chech-Adrar Desert, the northern part of Grand Erg Oriental, the Atouila Desert to the Ouarane Desert, the Mediterranean coast, the eastern side of Nubian Desert and Bodélé Depression; 3) Dust devils occur most frequently from April to August and are mainly concentrated in the central part of North Africa, especially in the southwest of Hoggar Mountains to the west of Air Mountains, the border area of Egypt - Sudan - Libya and the vicinity of Tibesti Plateau; 4) The spatio-temporal distribution of AI is correlated more with the dust devils emission whereas the annual average contributions by dust storms and dust devils are 61.3% and 38.7%, respectively. This study discovers a new area of dust emissions by dust devils, and provides a better explanation for the spatio-temporal distribution of AI in North Africa.

Traditional Chinese versus integrative treatment in elderly patients with isolated systolic hypertension: a multicenter, randomized, double-blind controlled trial.

BACKGROUND: Isolated systolic hypertension (ISH) is a common disease in elderly people, threatening their health. Traditional Chinese medicine (TCM) treatment or integrative treatment had advantages in improving quality of life and protecting target organs, but need to be proved by large evidence-based researches. OBJECTIVE: To observe the effects of TCM treatment (Jiangya Capsule) or integrative treatment (combination of Jiangya Capsule and nimodipine) on blood pressure and vasoactive agents, and their safety in elderly ISH patients. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS: A multicenter, randomized, double-blind controlled trial was adopted. A total of 270 elderly ISH patients recruited from Xiyuan Hospital, and TCM Hospital and Community Health Service Centers of Yanqing County of Beijing were randomly divided into 3 groups: TCM group (Jiangya Capsule plus nimodipine simulation, 90 cases), integrative group (Jiangya Capsule plus nimodipine, 90 cases) and Western medicine (WM) group (nimodipine plus Jiangya Capsule simulation, 90 cases). They were all treated for 4 weeks. MAIN OUTCOME MEASURES: Before and after 4-week treatment, office blood pressure, 24-hour ambulatory blood pressure, serum nitric oxide (NO), and plasma endothelin-1 (ET-1), thromboxane B2 (TXB2) and 6-keto-prostaglandin 1alpha (6-keto-PGF1alpha) were detected, and safety evaluation was conducted. RESULTS: After 4-week treatment, 5 patients in TCM group were lost to follow-up and another 5 patients were excluded, and 80 patients finished the trial; 7 patients in integrative group were lost to follow-up and another 7 patients were excluded, and 76 patients finished the trial; 2 patients in WM group were lost to follow-up and another 3 patients were excluded, and 85 patients finished the trial. After treatment, systolic blood pressure (SBP) decreased in each group (P<0.05), and integrative treatment was superior to TCM or WM treatment in decreasing SBP (P<0.05). Twenty-four hour average SBP and day average SBP decreased significantly in each group, and night average SBP decreased in integrative group, and integrative treatment was superior to TCM or WM treatment in decreasing day average SBP. Serum NO and plasma 6-keto-PGF1alpha levels were elevated and plasma ET-1 and TXB(2) levels were reduced after treatment, and integrative treatment was superior to TCM or WM treatment in reducing plasma TXB(2) level. CONCLUSION: TCM treatment or integrative treatment has affirmative effects and safety in treating elderly ISH patients, and integrative treatment has superiority in improving some indexes, and deserves further study.

[Effect of an integrative medical regimen on levels of vascular endothelial function and hypersensitive C-reactive protein in elderly patients with isolated systolic hypertension].

OBJECTIVE: To observe the effect of a integrative medical regimen (IMR), i.e. combined use of Jiangya Capsule (JYC) and Nimodipine (ND), on blood pressure, TCM clinical symptoms, and blood levels of vascular endothelial function and hypersensitive C-reactive protein (hs-CRP) in elderly patients with isolated systolic hypertension (EISH). METHODS: Adopting randomized, double-blinded and controlled principle, a trial was conducted on 135 patients with EISH by randomized them into three groups, they were administered IMR (Group A), JYC plus ND simulator (Group B) and ND plus JYC simulator (Group C) respectively, for 4 weeks. Changes of blood pressure and TCM symptoms, as well as the levels of serum nitric oxide (NO), plasma endothelin-1 (ET-1), 6-keto-prostaglandin 1alpha (6-keto-PGF(1alpha)), thromboxane B2 (TXB2) and hs-CRP were observed before and after treatment. RESULTS: After treatment the systolic blood pressure reduced and clinical symptoms improved, with serum NO and 6-keto-PGF(1alpha) lelels elevated, plasma ET-1, TXB2 and serum hs-CRP decreased in all the three groups (P<0.05 or P<0.01). But the inter-group comparisons showed that the effect in Group A was superior to the other two groups in decreasing systolic pressure, and superior to Group C in improving clinical symptoms, elevating serum NO and decreasing plasma TXB2 (P <0.05). CONCLUSION: The integrative medical regimen of combined use JYC and ND has markedly effect in lowering blood pressure, it could obviously improve the symptoms and vascular endothelial function, and inhibit the level of inflammatory factor in patients with EISH.

Long range trans-Pacific transport and deposition of Asian dust aerosols.

The deposition of Asian dust aerosols during their trans-Pacific transport might cause significant marine phytoplankton biomass increases. However, the knowledge of the trans-Pacific dust transport, deposition, and spatial distribution is still poor due to a lack of continuous and simultaneous observations in the Asian subcontinent, the north Pacific Ocean, and North America. The severe Asian dust storm during 6 to 9 April 2001 provided an opportunity to gain a better understanding of trans-Pacific dust transport and deposition, using a comprehensive set of observations from satellites, ground-based light detection and ranging, aircraft, and surface observation networks. The observations and model simulations outline the general pattern of dust transport, deposition, vertical profile, and spatial distribution. The following points were observed: (1) the surface dust concentrations decreased exponentially with the increasing dust transport distance from 80 degrees E to 120 degrees W along the transport pathway; (2) the altitude of the dust concentration peak increased with increasing transport distance in the north Pacific region; and (3) the spatial distribution of dust deposition mainly depended on the trans-Pacific transport route.

Uptake effects of toxic heavy metals from growth soils into jujube and persimmon of China.

Compared with other agricultural plants, information about uptake effects of toxic heavy metals from growth soils into persimmon and jujube are scarce. In this study, the single and comprehensive uptake effects of five toxic heavy metals (Pb, As, Cd, Cr, and Hg) between the two fruits and their growth soils were investigated. The results showed that the average concentrations of heavy metals in the two fruits were found to be 30 (Pb), 6.6 (As), 2.3 (Cd), 38 (Cr), and 0.33 (Hg) µg/kg, respectively. The average concentrations of heavy metals in their growth soils were 26.31 (Pb), 9.63 (As), 0.12 (Cd), 57.6 (Cr), and 0.049 (Hg) mg/kg, respectively. An uptake effect was observed for the two fruits. The values of Nemerow pollution index (NPI) in the two fruits and their growth soils were 0.10 and 0.55, respectively. The average bioconcentration factor (BCF) values of Pb, As, Cd, Cr, and Hg in the two fruits were 0.0012, 0.00075, 0.021, 0.00077, and 0.012, respectively. Based on the residue levels of toxic heavy metals in the growth soils and soil parameters, the prediction models for NPI and BCF were established, with the adjusted regression coefficients of 0.65 (NPI) and 0.81 (BCF). The contribution rates of different soil parameters to NPI were 21.7% (OC), 16.1% (Pb), 17.1% (Cr), 19.8% (Cd), and 25.4% (As), respectively. The contribution rates of different soil parameters to BCF were 10.2% (OC), 9.4% (Cr), and 80.4% (Cd), respectively.

Distribution, relationship, and risk assessment of toxic heavy metals in walnuts and growth soil.

Walnut is one of the most popular nuts worldwide and contains various mineral nutrients. Little is known, however, about the relationship between toxic heavy metals in walnuts and growth soil. In this study, we investigated the distribution, relationship, and risk assessment of five toxic heavy metals-lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd), and mercury (Hg)-in walnuts and growth soil in the main production areas of China. The results showed that the main heavy metal pollution in walnut and soil was Pb and Cd. Regionally, positive relationships existed between heavy metals and the pH and organic matter of soil. In addition, we observed a notable uptake effect between walnut and growth soil. In this study, we found a significant correlation (r = 0.786, P < 0.05) between the bioconcentration factors and the longitude of the sampling areas. The risks (total hazard quotients) of five heavy metals toward children and adults by dietary walnut consumption were 46.8 and 56.2%, respectively. The ability to identify toxic heavy metal pollution in walnuts and growth soil could be helpful to screen suitable planting sites to prevent and control heavy metal pollution and improve the quality and safety of walnut.

Pesticide residues in nut-planted soils of China and their relationship between nut/soil.

Twenty-nine pesticide residues in nut-planted soils from China were investigated. One organophosphate (chlorpyrifos) was detected in 5.3% soils, and the residue levels of 7.2 µg/kg to 77.2 µg/kg. The concentrations of six organochlorines (DDT, HCH, endosulfan, quintozene, aldrin and dieldrin) detected in 78.9% soils were 0.6 µg/kg to 90.1 µg/kg. The residue levels of six pyrethroids (bifenthrin, fenpropathrin, cyhalothrin, cypermethrin, fenvalerate and deltamethrin) detected in 65.8% soils were 1.5 µg/kg to 884.3 µg/kg. Triadimefon and buprofezin were found in 71.1% and 52.6% samples, respectively, with the corresponding concentrations of 9.8 µg/kg to 193.7 µg/kg and 87.9 µg/kg to 807.4 µg/kg. The multiple residues were found in 76.3% soils. A significant correlation between pesticide residues in nuts and soils was observed, with the correlation coefficient (r) 0.83 (P < 0.001). In addition, the bioconcentration factor (BCF) values for the explanation of pesticides from soils into nuts were ranged from 0.8 to 16.5. The results showed that some pesticides could accumulate in nut by the uptake effect from soil.

Observation of aerosol number size distribution and new particle formation at a mountainous site in Southeast China.

To quantify the physical/chemical properties, and the formation and growth processes of aerosol particles on mountainous regions in Southeast China, an intensive field campaign was conducted from April to July 2008 on the top of Mt. Huang (1840m above mean sea level). The average particle number concentration was 2.35×103cm-3, and the ultrafine particles (<0.1µm) represented 70.5% of the total particle number concentration. Excluding the accumulation mode particles, the average daytime particle number concentrations were prominently higher than those measured at nighttime, suggesting there was a diurnal pattern of changes between planetary boundary layer and free troposphere air. The aerosol spectra were classified into two categories: the first category (FCS) exhibited a clear diurnal cycle, with relatively higher number concentration (3.19×103cm-3), smaller sizes and air masses from the inland; the second category (SCS) presented less obvious diurnal cycle, with lower number concentration (1.88×103cm-3), larger sizes and air masses from coastal regions. Air mass sources, weather conditions, and new particle formation (NPF) events were responsible for the differences of these two particle spectra. Six NPF events were identified, which usually began at 10:00-11:00 LT, with the estimated formation rate J10 in the range of 0.09-0.30cm-3s-1 and the growth rate at 1.42-4.53nmh-1. Wind speed, sulfur dioxide and ozone concentrations were higher on NPF days than those on non-NPF days, whereas temperature, relative humidity, concentrations of nitrogen oxide and carbonic oxide were lower on NPF days. Sulfur dioxide and ozone might be main potentially precursor gases for those NPF events. The NPF events at Mt. Huang corresponded closely to a southwest winds. These results are useful for improving our understanding of the main factors controlling the variation of aerosol size distribution and NPF events in this region.