Potential causal links and mediation pathway between urban greenness and lung cancer mortality: Result from a large cohort (2009 to 2020).

Urban greenness, as a vital component of the urban environment, plays a critical role in mitigating the adverse effects of rapid urbanization and supporting urban sustainability. However, the causal links between urban greenness and lung cancer mortality and its potential causal pathway remain poorly understood. Based on a prospective community-based cohort with 581,785 adult participants in southern China, we applied a doubly robust Cox proportional hazard model to estimate the causal associations between urban greenness exposure and lung cancer mortality. A general multiple mediation analysis method was utilized to further assess the potential mediating roles of various factors including particulate matter (PM1, PM2.5-1, and PM10-2.5), temperature, physical activity, and body mass index (BMI). We observed that each interquartile range (IQR: 0.06) increment in greenness exposure was inversely associated with lung cancer mortality, with a hazard ratio (HR) of 0.89 (95 % CI: 0.83, 0.96). The relationship between greenness and lung cancer mortality might be partially mediated by particulate matter, temperature, and physical activity, yielding a total indirect effect of 0.826 (95 % CI: 0.769, 0.887) for each IQR increase in greenness exposure. Notably, the protective effect of greenness against lung cancer mortality could be achieved primarily by reducing the particulate matter concentration.

Spatial Distribution and Risk Assessment of Heavy Metal(oid)s Contamination in Topsoil around a Lead and Zinc Smelter in Henan Province, Central China.

A total of 137 farmland soil samples were collected around a lead/zinc smelter within 64 km2. The concentration, spatial distribution, and potential source of nine heavy metal(oid)s (As, Cd, Co, Cr, Cu, Ni, Pb, V, and Zn) in soils and their potential ecological risk were investigated in detail. The results showed that the average concentrations of Cd, Pb, Cr and Zn in these soils were higher than their background value in Henan Province, and the average content of Cd was 2.83 times of the risk screening values in the national standard of China (GB 15618-2018). According to the distribution of different heavy metal(oid)s in soils, Cd and Pb in soil decrease gradually with the increase of distance from the smelter to the surrounding area. This indicates that the Pb and Cd originate from smelters via airborne practices according to the typical air pollution diffusion model. The distribution of Zn, Cu, and As were similar to Cd and Pb. However, Ni, V, Cr, and Co were mainly affected by soil parent materials. The potential ecological risk of Cd was higher than those of other elements, and the risk grade of the other eight elements was mainly low. The polluted soils with significantly high and high potential ecological risk covered 93.84% of all the studied regions. This should be of serious concern to government. The results of a principal component analysis (PCA) and cluster analysis (CA) show that Pb, Cd, Zn, Cu, and As were the elements mainly stemmed from smelter and other types of plants, with a contribution rate of 60.08%, while Co, Cr, Ni, and V are mainly caused by nature, with a contribution rate of 26.26%.

Improving the mapping accuracy of soil heavy metals through an adaptive multi-fidelity interpolation method.

Soil heavy metal pollution poses a serious threat to environmental safety and human health. Accurately mapping the soil heavy metal distribution is a prerequisite for soil remediation and restoration at contaminated sites. To improve the accuracy of soil heavy metal mapping, this study proposed an error correction-based multi-fidelity technique to adaptively correct the biases of traditional interpolation methods. The inverse distance weighting (IDW) interpolation method was chosen and combined with the proposed technique to form the adaptive multi-fidelity interpolation framework (AMF-IDW). In AMF-IDW, sampled data were first divided into multiple data groups. Then one data group was used to build the low-fidelity interpolation model through IDW, while the other data groups were treated as high-fidelity data and used for adaptively correcting the low-fidelity model. The capability of AMF-IDW to map the soil heavy metal distribution was evaluated in both hypothetical and real-world scenarios. Results showed that AMF-IDW provided more accurate mapping results compared with IDW and the superiority of AMF-IDW became more evident as the number of adaptive corrections increased. Eventually, after using up all data groups, AMF-IDW improved the R2 values for mapping results of different heavy metals by 12.35-24.32%, and decreased the RMSE values by 30.35%-42.86%, indicating a much higher level of mapping accuracy relative to IDW. The proposed adaptive multi-fidelity technique can be equally combined with other interpolation methods and provide promising potential in improving the soil pollution mapping accuracy.

Insights into As accumulation in soil-groundwater-wheat-hair system of suburban farmland: Distribution, transfer and potential health risk.

Health risks caused by arsenic (As) contamination in soils and its migration in environmental media have attracted much attention. In this study, suburban farmland of KF city in the ecotone of the Yellow River and Huaihe River Basin was taken as the research area. A series of samples including topsoils (246), profile soils (280), matched wheat grains (22 groups), groundwater (26) and human hair (355) were collected. As distribution and transfer in soil-groundwater-wheat-hair (SGWH) system in typical sites were explored, and comprehensive health risk of As in SGWH system was assessed based on US EPA model and local exposure parameters. The results showed that spatial distribution of total As presented a significant high value area, and higher As contents (in the range of 0.45-29.86 mg kg-1) and bioavailability was mainly in topsoils, which indicated that anthropogenic sources have led to As enrichment in studied area. Also, it was found that the As contents in 95 % of wheat grain samples were higher than that in the control soils, and 9 % groundwater samples were above national Class I standards. Especially, average As content in hair in typical sites was obviously influenced by that in soil, wheat and groundwater. Moreover, As migration curve along soil → wheat (groundwater) → hair appeared an irregular 'V' shape, and transfer coefficients of Tf water/soil (10-5), Tf wheat/soil (10-3), Tf hair/soil (10-2), Tf hair/wheat (101) and Tf hair/water (104) presented an obvious increasing trend of magnitude, implying that human body has a higher As enrichment risk. Furthermore, comprehensive health risks for children and adults in typical sites were significant, while wheat is the main risk medium. In general, arsenic accumulation in human hair is good consistent with EPA health risk model, and their combination can better evaluate environmental exposure risk of As.

Assessment of Cd Pollution in Paddy Soil-Rice System in Silver Mining-Affected Areas: Pollution Status, Transformation and Health Risk Assessment.

Mining activities are one of the main contamination sources of Cd in soil. However, the information about the influence of silver mining on Cd pollution in soil in mining-affected areas is limited. In the present study, sixteen paired soil and rice grain samples were collected from the farmland along the Luxi River nearby a silver mine in Yingtan City, Jiangxi Province, China. The total, bioavailable, and fraction of Cd in soil and Cd content in rice grain were determined by inductively coupled plasma mass spectrometry. The transformation of Cd in the soil-rice system and potential health risk via consumption of these rice grains were also estimated. The results showed that Cd concentration in these paddy soils ranged from 0.21 to 0.48 mg/kg, with the mean Cd concentration (0.36 mg/kg) exceeded the national limitation of China (0.3 mg/kg, GB 15618-2018). Fortunately, all these contaminated paddy soils were just slightly polluted, with the highest single-factor pollution index value of 1.59. The DTPA- and CaCl2-extractable Cd in these paddy soils ranged from 0.16 to 0.22 mg/kg and 0.06 to 0.11 mg/kg, respectively, and the acid-soluble Cd occupied 40.40% to 52.04% of the total Cd, which was the highest among different fractions. The concentration of Cd in rice grain ranged from 0.03 to 0.39 mg/kg, and the mean Cd concentration in rice grain (0.16 mg/kg) was within the national limitation of China (0.2 mg/kg, GB 2762-2017). The bioaccumulation factor of Cd in rice grain ranged from 0.09 to 1.18, and its correlation with various indicators was nonsignificant (p < 0.05). Health risk assessment indicated that the noncarcinogenic risk for local rice consumers was within the acceptable range, but the carcinogenic risk (CR) was ranging from 1.24 × 10-2 to 1.09 × 10-3 and higher than the acceptable range (1.0 × 10-4), indicating that the local rice consumers suffered serious risk for carcinogenic diseases. The results of the present study can provide reference for safety production of rice in silver mining-affected areas.

A New Sight of Influencing Effects of Major Factors on Cd Transfer from Soil to Wheat (Triticum aestivum L.): Based on Threshold Regression Model.

Due to the high toxicity and potential health risk of cadmium (Cd), the influencing effects of major factors (like pH, OM, and clay, etc.) on Cd bioaccumulation and transfer from soil to crop grains are highly concerned. Multiple linear regression models were usually applied in previous literature, but these linear models could not reflect the threshold effects of major factors on Cd transfer under different soil environmental conditions. Soil pH and other factors on Cd transfer in a soil-plant system might pose different or even contrary effects under different soil Cd exposure levels. For this purpose, we try to apply a threshold regression model to analyze the effects of key soil parameters on Cd bioaccumulation and transfer from soil to wheat. The results showed that under different soil pH or Cd levels, several factors, including soil pH, organic matter, exchangeable Cd, clay, P, Zn, and Ca showed obvious threshold effects, and caused different or even contrary impacts on Cd bioaccumulation in wheat grains. Notably, the increase of soil pH inhibited Cd accumulation when pH > 7.98, but had a promotional effect when pH ≤ 7.98. Thus, threshold regression analysis could provide a new insight that can lead to a more integrated understanding of the relevant factors on Cd accumulation and transfer from soil to wheat. In addition, it might give us a new thought on setting regulatory limits on Cd contents in wheat grains, or the inhibitory factors of Cd transfer.

Simultaneous Removal of Cu2+, Cd2+ and Pb2+ by Modified Wheat Straw Biochar from Aqueous Solution: Preparation, Characterization and Adsorption Mechanism.

As an eco-friendly and efficient adsorbent for removal of potential toxic metals from aqueous solution, biochar has received widespread attention. In the present study, wheat straw biochar (BC) and corresponding modified biochar (HNC) were used to remove Cu2+, Cd2+ and Pb2+ from an aqueous solution. The influence of the environment factors on metals adsorption and adsorption mechanism were discussed in detail. The results showed that the HNC had porous structures and owned ample functional groups (-OH, -COOH and C-N groups) compared with the BC. In the single system, the adsorption capacities of HNC for Cu2+, Cd2+ and Pb2+ at a pH of 5.5 were 18.36, 22.83 and 49.38 mg/g, which were 76.89%, 164.36% and 22.75% higher than that of the BC, respectively. In addition, the adsorption process of Cu2+ and Cd2+ on BC and HNC fitted to the Langmuir isotherm model and pseudo-second-order kinetics, but the adsorption of Pb2+ on BC and HNC fitted to the Langmuir isotherm model and pseudo-first-order kinetics. Adsorption isotherms indicated that the adsorption of Cu2+, Cd2+ and Pb2+ by BC and HNC was a spontaneous endothermic process. The competitive adsorption of mixed metal ions (Cu2+, Cd2+ and Pb2+) revealed that HNC was more preferential to adsorb Cu2+ compared with Cd2+ and Pb2+. Furthermore, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses revealed that the main adsorption mechanisms were surface complexation and precipitation, and the adsorbed Cu2+, Cd2+ and Pb2+ on HNC mainly exist as CuO, Cd(OH)2, Pb3O4 and Pb(OH)2.

Metal(loid)s Spatial Distribution, Accumulation, and Potential Health Risk Assessment in Soil-Wheat Systems near a Pb/Zn Smelter in Henan Province, Central China.

To understand the influence of Pb/Zn smelter on surrounding environment, 110 soil and 62 wheat grain samples (62 paired samples) were collected nearby a Pb/Zn smelter in Jiaozuo City, Henan Province, China. The content and spatial distribution of metal(loid)s in the soil-wheat system, and the potential health risk via consumption of wheat grains were determined. Results showed that the average content of Pb, Cd, As, Cu, Zn, and Ni in soil were 129.16, 4.28, 17.95, 20.43, 79.36, and 9.42 mg/kg, respectively. The content of Cd in almost all soil samples (99.1%) exceeded the national limitation of China (0.6 mg/kg). Spatial distribution analysis indicated that atmospheric deposition might be the main pollution source of Pb, Cd, As, and Zn in soil. In addition, the average content of Pb, Cd, As, Cu, Zn, and Ni in wheat grain were 0.62, 0.35, 0.10, 3.7, 35.77, and 0.15 mg/kg, respectively, with the average Pb and Cd content exceeding the national limitation of China. The average bioaccumulation factor of these metal(loid)s followed the following order: Zn (0.507) > Cu (0.239) > Cd (0.134) > Ni (0.024) > Pb (0.007) > As (0.006). Health risk assessment indicated that the average noncarcinogenic risk of children (6.78) was much higher than that of adults (2.83), and the carcinogenic risk of almost all wheat grain is higher than the acceptable range, with an average value of 2.43 × 10−2. These results indicated that humans who regularly consume these wheat grains might have a serious risk of noncarcinogenic and carcinogenic diseases.

Combination of UNMIX, PMF model and Pb-Zn-Cu isotopic compositions for quantitative source apportionment of heavy metals in suburban agricultural soils.

Quantitative identification of heavy metals (HM) sources in soils is key to prevention and control of heavy metal pollution. In this study, UNMIX, PMF (Positive matrix factorization) model and Pb-Zn-Cu isotopic compositions were combined to quantitatively identify heavy metal sources in a suburban agricultural area of Kaifeng, China. Using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) and ICP-MS, we measured Pb, Zn and Cu stable isotopic compositions, HM concentrations and HM chemical fractions in studied soils, as well as potential sources around the highly polluted site, including total suspended particle, compound fertilizer, irrigated river water and sediments. The results showed that total contents and chemical fractions of heavy metals, as well as Pb-Zn-Cu isotopic compositions presented great variation in different sites, which implied that heavy metal accumulation was obviously affected by local anthropogenic pollution source. UNMIX and PMF presented good agreement on source apportionment that industrial and agricultural activities (61.74% and 60.75% for UNMIX and PMF, respectively) were the major contributors to heavy metal accumulation in the study area. Especially, sewage irrigation and atmosphere deposition accounted for a large proportion (28.14% and 41.03% for UNMIX and PMF, respectively). Moreover, isotopic compositions of Pb, Zn and Cu in highly polluted soils and environment media gave further confirmation that sewage irrigation and atmosphere deposition were primary anthropogenic source. Therefore, combination of UNMIX, PMF model and Pb-Zn-Cu isotopic compositions showed good coordination in quantitative and specific source identification of heavy metals in agricultural soils.

[Soil Properties, Heavy Metal Accumulation, and Ecological Risk in Vegetable Greenhouses of Different Planting Years].

The vegetable greenhouse soils in Yanglou Town, Ruzhou City, Henan Province were taken as the research object in the present study to explore the difference in soil physical and chemical properties and the total and fraction of heavy metals of different planting years. The potential ecological risks of heavy metals in greenhouse soils with different planting years were assessed by using single and comprehensive potential ecological risk index methods. The results showed that the soil pH of vegetable greenhouses increased, and fertility factors such as organic matter, available phosphorus, and alkali-hydrolyzable nitrogen accumulated to a certain extent compared to the control group, whereas catalase showed a decreasing trend. Correlation analysis showed that the planting years were significant positively correlated with pH (P<0.05) and organic matter (P<0.01) and significant negatively correlated with catalase (P<0.01). The amount of heavy metals in the vegetable greenhouse soils increased with the increase in planting years, among which Cu, Zn, and Cd increased most obviously, with maximum increases of 129.14%, 204.17%, and 161.11%, respectively. The proportion of acid-soluble and reducible heavy metals in the vegetable greenhouse soils also increased gradually with the planting years, and the proportion of residual heavy metals decreased correspondingly, which resulted in the heavy metals transforming into fractions easily absorbed by plants. The results of the single potential ecological risk index showed that Cd in vegetable greenhouse soils had a strong ecological risk with the increase in planting years, whereas Cu, Pb, Zn, and Ni were in the mild risk category. The comprehensive potential ecological risk index showed that the heavy metals in the vegetable greenhouse soils of different planting years have reached a strong or very strong ecological risk.

Biodegradation of di-n-octyl phthalate by Gordonia sp. Lff and its application in soil.

A previous isolated Gordonia sp. (Lff) was used to degrade di-n-octyl phthalate (DOP) contamination in both aqueous solution and soil. The influence of temperature, pH, inoculum size, salt content and initial concentration of DOP on DOP degradation by Lff were analysed. The response of soil bacterial community to DOP and Lff was also analysed by Illumina MiSeq sequence method. Results showed that the optimal temperature, pH, inoculum size and salt content were 35oC, 8.0, 5% and <5%, respectively. Under the optimal condition, more than 91.25% of DOP with different initial concentrations (100-2000 mg/L) could be degraded by Lff. Kinetics analysis indicated that biodegradation of DOP by Lff could be described by first-order kinetics (R2 > 0.917) with the half-life (t1/2) changing irregularly between 0.58 and 0.83 d. In addition, Lff enhanced the removal of DOP in soil and alleviated the toxicity of DOP on soil microorganisms. Furthermore, its influence on soil bacterial community is not obvious. These results suggested that Lff was effective in remediating DOP contamination in different environments.

Migration of heavy metals in the soil-grape system and potential health risk assessment.

The accumulation of heavy metals in soil may introduce them to the food chain and cause health risks for humans. In the present study, 43 pairs of soil and grape samples (leaf and fruit) were collected form vineyards in the suburbs of Kaifeng city (wastewater-irrigated area in Henan Province, China) to assess the heavy metal (Pb, Cd, Cu, Zn and Ni) pollution level in soil, heavy metal accumulation in different grape tissues and the potential health risk via consumption of grapes. The results showed that the average contents of Pb, Cd, Cu, Zn and Ni in vineyard soil were 42.27, 3.08, 62.33, 262.54 and 26.60 mg/kg, respectively. Some of these soil samples were severely contaminated with Cd and Zn, with an average pollution index (Pi) of 5.14 and 0.88, respectively. Most of these soil samples were severely polluted by heavy metals, with an average Nemerow integrated pollution index (PN) of 3.77. The bioavailable heavy metals were negatively correlated with soil pH and positively correlated with soil organic matter (OM). In addition, heavy metals were more likely to accumulate in grape leaves, and their contents in grape pulp were all within the maximum permissible limit set by China (GB 2762-2017). The average bioaccumulation factors (BFs) of Pb, Cd, Cu, Zn and Ni in grape pulp were 0.007, 0.096, 0.160, 0.078 and 0.023, respectively. Health risk assessment indicated that there was no noncarcinogenic risk for grape consumers (adults and children). However, the carcinogenic risk (CR) ranged from 4.95 × 10-7 to 2.17 × 10-4, and the CR value of three grape samples was higher than 10-4, indicating that a probability of carcinogenic disease existed for humans who regularly consumed the grapes from this region.

A novel maize biochar-based compound fertilizer for immobilizing cadmium and improving soil quality and maize growth.

In this study, a novel biochar-based compound fertilizer (BCF) was synthesized with maize straw biomass, diatomite, triple superphosphate and urea at different temperatures (300 °C, 450 °C, 600 °C) and mixture proportions (5:1:1:x and 10:1:1:x). An investigation was conducted into the effects of BCF at low application rates on the immobilization of available cadmium, soil fertility and maize growth. The lab incubation experiments showed that the low doses of BCF (B5PNx and B10PNx) contributed to a significant reduction of the Cd availability in soil, with the highest reduction rate of available Cd up to 44.13%. Field experiments demonstrated that the low doses ( < 0.1%) of BCF（especially for B5PN600）led to the improvement of soil fertility and maize growth (including maize yield) and the significant reduction of Cd contents in maize grains. The increase of pyrolysis temperature could enhance the biochar adsorption capacity for Cd2+ by increasing both specific surface areas and total pore volume. The modification of urea, diatomite and triple superphosphate played a vital role on cadmium immobilization, soil improvement and maize growth by forming porous adsorption, precipitates or complexation with the increase of functional groups, as well as supplementation of N, P, Si nutrients. This study suggested that the biochar-based compound fertilizer (BCF with a mixture ratio of 5:1:1:x) produced at 600 °C could be served as a promising and eco-friendly remediation agent for the arable soils polluted with Cd, with reduction of chemical fertilizers.

Compound health risk assessment of cumulative heavy metal exposure: a case study of a village near a battery factory in Henan Province, China.

The concentrations of the heavy metals Hg, As, Ni, Pb, Cd, Cr, Cu and Zn in soil, groundwater, air, and locally produced grain (wheat and corn) and vegetables were determined in a village near a battery factory in Xinxiang, Henan Province, China. A multimedia, multipathway health risk assessment of heavy metal exposure was carried out using the health risk model recommended by the United States Environmental Protection Agency (US EPA). The results showed that the concentrations of Cd in soil, Cd and Pb in wheat, Hg in corn, Cd, Hg, and Pb in vegetables, and Cd and As in PM2.5, PM10, and TSP were all higher than the corresponding limits for heavy metals in China. The non-carcinogenic risks (HIs) for all environmental media were higher in children than in adults, and the carcinogenic risks (TCRs) of heavy metal exposure in other media except for soil were higher in adults than in children. The total HI and TCR in adults and children were higher than the standard limit values because of heavy metal exposure through soil, groundwater, PM10, grain and vegetables. Cd was the most significant heavy metal in terms of HI and TCR factors; among the evaluated pathways, the contribution of diet was the largest. The HI and TCR caused by dietary crops account for 96.7% and 98.9% of the total in adults and 90.2% and 96.2% of the total in children, respectively. To maintain the health of the residents in the study area, it is strongly recommended to stop planting edible agricultural products immediately, start buying grain and vegetables from outside the study area, and strictly strengthen the control of heavy metal pollution in the study area. The source apportionment results show that Cd, Ni and As were mainly from industrial sources, which was related to sewage irrigation and battery plant deposition, and Pb and Cr were mainly from agricultural activities.

Long-term stabilization of Cd in agricultural soil using mercapto-functionalized nano-silica (MPTS/nano-silica): A three-year field study.

Cadmium (Cd) contamination in agricultural soil is a worldwide environmental problem. In situ stabilization has been considered an effective approach for the remediation of Cd-contaminated agricultural soil. However, information about the long-term effects of amendment on soil properties and stabilization efficiency remains limited. In the present study, mercapto-functionalized nano-silica (MPTS/nano-silica) was used to stabilize Cd in contaminated agricultural soil under field conditions for three years (with application rates of 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1.0%). The application of MPTS/nano-silica reduced the soil aggregate stability (PDA0.25) (14.8%) and available K (24.9%) and significantly increased the soil dehydrogenase (DHA) (43.4%), yield of wheat grains (33.5%) and Si content in wheat tissues (55.2% in leaf, 50.4% in stem, and 37.7% in husk) (p < 0.05). More importantly, MPTS/nano-silica decreased the leachability (36.0%) and bioavailability (54.3%) of Cd in the soil and transformed Cd into a more stable fraction. The content of Cd in wheat grains decreased by 53.9%, 61.9% and 54.1% in 2017, 2018 and 2019, respectively, in comparison with the control. These results indicated that MPTS/nano-silica has long-term stabilization effects on Cd in agricultural soil and is a potential amendment for the remediation of Cd-contaminated agricultural soils.

[Spatial Distribution and Risk Assessment of Heavy Metal Contamination in Surface Farmland Soil Around a Lead and Zinc Smelter].

Surface farmland soil samples were collected from 135 different sites in a 64 km2 area around a lead and zinc smelter in Jiaozuo City, China. The concentration of the selected heavy metals (Cu, Zn, Pb, Cr, Cd, Ni, V, and Co) was analyzed and the spatial distribution of these heavy metals in the farmland was determined using the kriging interpolation technique (ArcGis 10.1). The enrichment factor, potential ecological risk model, and potential health risk model were used to assess the contamination level and potential risk of heavy metals in farmland surface soil. The results show that the average contents of Cd, Pb, Cr, and Zn in farmland soil are higher than the background content of these metals in the Henan Province and the average content of Cd is 2.8 times higher than that of class Ⅱ of the environmental quality standard for soils in China (GB 15618-1995). The heavy metal contamination in the west of the study area is higher than that in the east and the soil around the lead and zinc smelter (within 3 km) is severely contaminated with Pb and Cd, which is consistent with the location of the industries causing the pollution. The enrichment factors show that the soil is severely contaminated with Cd; partial sampling points are seriously contaminated with Pb, Cu, and Zn; the Cr and Co pollution is small; and Ni and V are almost not affected by human activities. The results of the risk assessment indicate that Cd poses serious ecological and health risks, Pb and Cu pose serious ecological risks, and Cr poses a serious cancer risk.

Biodegradation of di-n-butyl phthalate by bacterial consortium LV-1 enriched from river sludge.

A stable bacterial consortium (LV-1) capable of degrading di-n-butyl phthalate (DBP) was enriched from river sludge. Community analysis revealed that the main families of LV-1 are Brucellaceae (62.78%) and Sinobacteraceae (14.83%), and the main genera of LV-1 are Brucella spp. (62.78%) and Sinobacter spp. (14.83%). The optimal pH and temperature for LV-1 to degrade DBP were pH 6.0 and 30°C, respectively. Inoculum size influenced the degradation ratio when the incubation time was < 24 h. The initial concentration of DBP also influenced the degradation rates of DBP by LV-1, and the degradation rates ranged from 69.0-775.0 mg/l/d in the first 24 h. Degradation of DBP was best fitted by first-order kinetics when the initial concentration was < 300 mg/l. In addition, Cd2+, Cr6+, and Zn2+ inhibited DBP degradation by LV-1 at all considered concentrations, but low concentrations of Pb2+, Cu2+, and Mn2+ enhanced DBP degradation. The main intermediates (mono-ethyl phthalate [MEP], mono-butyl phthalate [MBP], and phthalic acid [PA]) were identified in the DBP degradation process, thus a new biochemical pathway of DBP degradation is proposed. Furthermore, LV-1 also degraded other phthalates with shorter ester chains (DMP, DEP, and PA).

[Assessment of Heavy Metal Pollution and its Health Risk of Surface Dusts from Parks of Kaifeng, China].

Fifty-two dust samples were collected from four parks [Longting Park (P(L)), Tieta Park (P(T)), Qingmingshanghe Park (P(Q)), Xiangguosi Park (P(X))] located in Kaifeng City, China. Concentrations of Hg and As in dusts were measured by atomic fluorescence spectrometry (AFS), while Cr, Cu, Zn, Pb, Ni and Cd were analyzed by inductively coupled plasma mass-spectrometry (ICP-MS). The heavy metal pollution of dust was assessed using Geo-accumulation index (Igeo) and pollution load index (PLI). The health risk due to exposure to heavy metals in dust was assessed using the model recommended by USEPA. The non-carcinogen (HI) and carcinogen health risks (TCR) were also calculated to evaluate the potential risks to adults. The results showed that the average contents of Hg, Cu, Zn, Cd and Pb were much higher than those in control samples and the background values of fluvo-aquic soil in China. The samples were seriously polluted by Hg and Pb, besides, there was.moderate pollution, slight pollution of Cu and Zn, and no pollution of As, Cr and Ni. The PLI from the 4 Parks indicated that there was serious heavy metals pollution of dust in P(X), moderate pollution in P%, and slight pollution in P(T) and P(Q). The average HI of heavy metals in the four Parks was lower than one. The average HI decreased in the order of P(L) > P(X), > P(T) > P(Q), while the average TCR decreased in the order of P(L) > P(Q) > P(x) > P(T). The contribution rate of HQ(As) to HI was about 43.51% , and that of CR(As) to TCR was about 70.11%.

[Soil record of black carbon during urbanization and its environmental implications].

This investigation selected the city of Nanjing, Jiangsu province of China, as the study area, and analyzed the concentrations of organic carbon (OC) and black carbon (BC) of ten soils profiles in three different groups, by wet chemical oxidation methods. The results showed that the concentration of BC ranged from 0.22 g x kg(-1) to 32.19 g x kg(-1) in all urban soil profiles, and the average concentration of BC reached 4.35 g x kg(-1). The average concentration of BC of the first group from ancient residential areas was 0.91 g x kg(-1), and that of the second group affected by ancient industrial activities was 8.62 g x kg(-1), the third group influenced by the modern industrial and traffic emission was 3.72 g x kg(-1). The ratio of BC/OC ranged from 0.03 to 1.59 in all profiles, and the average was 0.29. The average ratio of BC/OC of three groups appeared in this order: the highest exists in the second group, followed by the third group, and the last is the first group. These data mean that some BC particles produced by local biomass and/or fossil fuel burning due to the industrial and transport activities during urbanization are recorded in soils. In addition, the contents of BC and the ratio of BC/OC may reflect different processes of human activities and pollution intensities of urban soils. It is concluded that the soil BC in urban area is mainly coming from fossil fuel burning, more specifically, BC in surface layer (present layer) is mainly from the exhaust particles of motor vehicles (especially diesel engine), while in ancient layer (cultural layer) it is possibly related to the historical coal use.

[Distribution and migration of heavy metals in soil profiles by high-resolution sampling].

The vertical distribution of heavy metals in soils profiles is a result of heavy metals accumulation and migration under combining influence of edaphic factors and environmental conditions. It's an important basis for evaluation of heavy metals pollution and remediation of contaminated soils. By traditional sampling methods, i.e., soils were sampled according to pedogenetic horizons, only very general information about element migration can be learned. In the current study, three sites near a steel factory were selected to represent three types of land use, i.e. forest, dry land for vegetable cultivation and rice paddy field. Soils were sampled horizontally by high-resolution sampling method. In the top of 40 cm soils were sectioned in 2 cm intervals, then 5 cm intervals in next 40 cm, and 10 cm intervals in the last 20 cm of profile. Total content of Cu, Zn, Pb, Cr and Cd were determined, and the vertical distribution of Cu, Zn, Pb, Cr, Cd in every profile was analyzed. The results indicated that enrichment of heavy metals appeared in the upper most layer of the natural forest soil that without any anthropic disturbance, and this phenomenon proved that heavy metals were coming from atmospheric deposition. We found that Cu, Zn and Pb moved downward in a short distance, Cd migrated relatively faster than Cu, Zn and Pb, while Cr had no recognizable location of migration front. In the soil profiles of dry land and paddy field, there were influences of agricultural practice, the distribution and movement of metals were thus different form those of the forest soil. In cultivated layer heavy metals were evenly distributed because soils in the upper layer were mixed by cultivation, however, bellow the cultivated layer obvious migration took place again. It is concluded that different heavy metals have different mobility and there is such a relative order: Cd>Cu>Zn>Pb. The study shows that the distribution pattern can be obtained with the currently adopted high-resolution sampling method, than traditional horizon sampling, and more precise migration distance and rates can be estimated.