加速小清河水污染综合治理的探讨

加速小清河水污染综合治理的探讨滨洲地区环保局陈俊善１小清河水污染综合治理进展情况小清河水污染综合治理工作在省委、省府的领导下，经主管部门的努力工作，取得了一定的成绩。３１个重点污染源限期治理项目（其中济南市２１个，淄博市１０个）已完成了１０个；淄博市...

发挥水利系统整体优势 当好保护淮河水资源“卫士”

在党中央、国务院的高度重视下,在淮河流域水资源保护领导小组的正确领导下,淮河治污的第一战役已初步告捷,取得了阶段性成果,到1997年底基本实现工业污染源达标排放,淮河水质已明显好转。在1997年治污攻坚战中,淮河流域水利战线上的广大职工,开展多种监测,对各省、市、县污染物排放量及出境水质实行全面监控,不断探索和完善水量、水质统一管理,认真履行水行政主管部门的职责。

Effects of Lead/Chromium Stress on Contents of Chlorophyll in Bryum argenteum and Barbula indica

[Objective] This study aimed to clarify the effects of Pb2＋ and Cr3＋ stress on the contents of chlorophyl in Bryum argenteum and Barbula indica. [Method] B. ar-genteum and B. indica were cultured in different concentrations of lead nitrate solu-tion or chromium chloride solution, to investigate the changes in contents of photo-synthetic pigments under lead and chromium single stress. [Result] The results showed that the effects of 1, 10 and 200 mg/L Pb2＋ on B. indica were greater than those on B. argenteum; the effects of 1, 50, 100 and 200 mg/L Cr3＋ on B. argen-teum were greater than those on B. indica. Total chlorophyl content in B. argen-teum and B. indica under different concentrations of Pb2＋ and Cr3＋ was decreased compared with that in control. The tolerance of B. indica to Pb2＋ pol ution was lower than that of B. argenteum, while the tolerance of B. indica to Cr3＋ pol ution was greater than that of B. argenteum. [Conclusion] Based on the conventional require-ments for monitoring materials, B. indica can be used as an indicator species to monitor heavy metal pol ution in the atmosphere of Zhengzhou.

Groundwater Contamination with NO_3-N in a Wheat-Corn Cropping System in the North China Plain

The North China Plain,where summer corn(Zea mays L.)and winter wheat(Triticum aestivum L.)are the major crops grown,is a major agricultural area in China.Permeable soils make the region susceptible to groundwater pollution by NO_3-N,which is applied to fields in large amounts of more than 400 kg NO_3-N ha^(-1)as fertilizer.A field experiment was established in 2002 to examine the relationship among N fertilization rate,soil NO_3-N,and NO_3-N groundwater contamination.Two adjacent fields were fertilized with local farmers' N fertilization rate(LN)and double the normal application rate(HN),respectively,and managed under otherwise identical conditions.The fields were under a traditional summer corn/winter wheat rotation.Over a 22-month period,we monitored NO_3-N concentrations in both bulk soil and soil pore water in 20-40 cm increments up to 180 cm depth.We also monitored NO_3-N concentrations in groundwater and the depth of the groundwater table.No significant differences in soil NO_3-N were observed between the LN and HN treatment.We identified NO_3-N plumes moving downward through the soil profile.The HN treatment resulted in significantly higher groundwater NO_3-N,relative to the LN treatment,with groundwater NO_3-N consistently exceeding the maximum safe level of 10 mg L^(-1),but groundwater NO_3-N above the maximum safe level was also observed in the LN treatment after heavy rain.Heavy rain in June,July,and August 2003 caused increased NO_3-N leaching through the soil and elevated NO_3-N concentrations in the groundwater.Concurrent rise of the groundwater table into NO_3-N- rich soil layers also contributed to the increased NO_3-N concentrations in the groundwater.Our results indicate that under conditions of average rainfall,soil NO_3-N was accumulated in the soil profile.The subsequent significantly higher- than-average rainfalls continuously flushed the soil NO_3-N into deeper layers and raised the groundwater table,which caused continuous groundwater contamination with NO_3-N.The results suggest that under common farming practices in the North China Plain,groundwater contamination with NO_3-N was likely,especially during heavy rainfalls,and the degree of groundwater contamination appeared to be proportional to the N application rates.Decreasing fertilization rates, splitting fertilizer inputs,and optimizing irrigation scheduling had potential to reduce groundwater NO_3-N contamination.

Response of meiofaunal and nematode communities to sewage pollution abatement:a field transplantation experiment

To assess the recovery rate of meiofaunal and nematode communities upon abatement of sewage pollution, a field transplantation experiment was conducted in Tat Tam, which is a non-polluted, shallow subtidal habitat on the southern portion of Hong Kong Island. The sediments used were from one site located in Victoria Harbour that was heavily influenced by sewage pollution, and one site in the outside-harbor area, which was relatively clean. In addition, sediments from Tat Tam were used as a control. Fresh sediments with meiofauna were collected from the aforementioned sites, placed in plastic trays and transplanted to Tat Tam. Sediments were retrieved at the beginning of the experiment and at 1-, 3-, and 8-weeks after transplantation for analysis of the meiofaunal and nematode communities as well as the sediment characteristics. The results showed that the meiofaunal and nematode communities in the control sediments were consistent at the four sampling periods, while it took three and eight weeks, respectively, for the nematode communities from the outside-harbor and inside-harbor sites to become similar to the control. These findings indicated that the relatively poor habitat quality and the nematode community composition in the sewage polluted inside-harbor sediments required a longer time for recovery than samples from the better habitat quality and the nematode community composition in the outside-harbor sediments.

Chromium(VI) Reduction in Wheat Rhizosphere

Reduction of Cr(VI) to Cr(III) were studied in a fresh wheat rhizosphere soil (Kuroboku, high humic andosol) pretreated with a basal fertilizer consisting of (NH4)2SO4, P2O5 and KH2PO4 and with K2Cr2O7 by using a rhizobox system. It was found that rhizosphere exerted a positive effect on Cr(VI) reduction. Part of the reason was the decrease of pH in the rhizosphere due to application of (NH4)2SO4, implying that application of physiologically acid fertilizers would reduce Cr(VI) toxicity to plants.

Estimation of As and Cu Contamination in Agricultural Soils Around a Mining Area by Reflectance Spectroscopy:A Case Study

Concentrations of Iron (Fe), As, and Cu in soil samples from the fields near the Baoshan Mine in Hunan Province, China, were analyzed and soil spectral reflectance was measured with an ASD FieldSpec FR spectroradiometer (Analytical Spectral Devices, Inc., USA) under laboratory condition. Partial least square regression (PLSR) models were constructed for predicting soil metal concentrations. The data pre-processing methods, first and second derivatives (FD and SD), baseline correction (BC), standard normal variate (SNV), multiplicative scatter correction (MSC), and continuum removal (CR), were used for the spectral reflectance data pretreatments. Then, the prediction results were evaluated by relative root mean square error (RRMSE) and coefficients of determination (R 2 ). According to the criteria of minimal RRMSE and maximal R 2 , the PLSR models with the FD pretreatment (RRMSE = 0.24, R 2 = 0.61), SNV pretreatment (RRMSE = 0.08, R 2 = 0.78), and BC-pretreatment (RRMSE = 0.20, R 2 = 0.41) were considered as the final models for predicting As, Fe, and Cu, respectively. Wavebands at around 460, 1 400, 1 900, and 2 200 nm were selected as important spectral variables to construct final models. In conclusion, concentrations of heavy metals in contaminated soils could be indirectly assessed by soil spectra according to the correlation between the spectrally featureless components and Fe; therefore, spectral reflectance would be an alternative tool for monitoring soil heavy metals contamination.

Estimation of Transported Pollutant Load from Small Urban Kahuwa River Micro-catchment in Lake Kivu, Democratic Republic of Congo

This study estimated pollutant load from Kahuwa micro-catchment into Lake Kivu. The micro-catchment was sampled monthly for a year at six locations to capture the contribution of agricultural land, industries and commercial blocks. Both wet and dry depositions in terms of TN （total nitrogen） and TP （total phosphorus） were estimated monthly. The level of pollution was estimated using LISEC index and IPO （organic pollution indices）. Results show that Kahuwa River micro-catchment is polluted mainly by waste dumping sites and industries within the micro-catchment. The general load to the outlet was respectively about 0.35 tons per year （t/yr） for BODs, 1.9 t/yr for COD, 32.73 t/yr for TP and 224.37 t/yr for TN. Atmospheric deposition of nutrient contributed for about 4% and 18% of TP, 3% and 0.01% of TN during dry and wet deposition, respectively.

Characteristics of diffuse pollution of nitrogen and phosphorous from a small town in the hilly area of the central Sichuan Basin,China

Hydrological and hydro-chemical monitoring of nitrogen(N) and phosphorus(P) in a small urbanized catchment was conducted in the hilly area of the central Sichuan Basin,China,from 2010 through 2011.The diffuse N and P loadings in different forms of total nitrogen(TN) and phosphorus(TP),dissolved nitrogen(DN) and phosphorus(DP),as well as particulate nitrogen(PN) and phosphorus(PP) were calculated based on runoff discharges and chemical analyses.The results revealed that the diffuse pollution concentrations of TN,DN,PN,TP,DP and PP exhibited large variations during rainfall events,with peak concentrations occurring during the initial period.For all of the measured parameters,the event mean concentrations(EMCs) were observed to clearly vary among rainfall events.The EMCs of TN,DN,PN,TP,DP and PP(for all of the observed rainfall events) were 10.04,6.62,3.42,1.30,0.47 and0.83 mg/L,respectively.The losses of diffuse N and P exhibited clear seasonal patterns and mainly occurred during the period from July through September,when the losses totaled 99.3 and 9.6 kg/ha for TN and TP,respectively,accounting for 75% and 74% of the total annual loadings.The mean annual loadings of TN and TP were 124.6 and 12.9 kg/ha,respectively.The results indicate that residential areas in the hilly areaof the central Sichuan Basin are subject to high diffuse N and P loadings,posing a serious risk to the receiving water quality.Ecological buffering belts are recommended to incorporate into the urbanized catchment to reduce diffuse pollution.

River Water Purification via a Coagulation-Porous Ceramic Membrane Hybrid Process

Membrane filtration technology combined with coagulation is widely used to purify river water.In this study,microfiltration(MF)and ultrafiltration(UF)ceramic membranes were combined with coagulation to treat local river water located at Xinghua,Jiangsu province,China.The operation parameters,fouling mechanism and pilot-scale tests were investigated.The results show that the pore size of membrane has small effect on the pseudo-steady flux for dead-end filtration,and the increase of flux in MF process is more than that in UF process for cross-flow filtration with the same increase of cross-flow velocity.The membrane pore size has little influence on the water quality.The analysis on membrane fouling mechanism shows that the cake filtration has significant influence on the pseudo-steady flux and water quality for the membrane with pore size of 50,200 and 500 nm.For the membrane with pore size of 200 nm and backwashing employed in our pilot study,a constant flux of 150L·m 2·h 1was reached during stable operation,with the removal efficiency of turbidity,total organic carbon(TOC)and UV254 higher than 99%,45%and 48%,respectively.The study demonstrates that coagulation-porous ceramic membrane hybrid process is a reliable method for river water purification.

Integrated evaluation system under randomness and fuzziness for groundwater contamination risk assessment in a little town, Central China

An integrated evaluation system under randomness and fuzziness was developed in this work to systematically assess the risk of groundwater contamination in a little town, Central China. In this system, randomness of the parameters and the fuzziness of the risk were considered simultaneously, and the exceeding standard probability of contamination and human health risk due to the contamination were integrated. The contamination risk was defined as a combination of "vulnerability" and "hazard". To calculate the value of "vulnerability", pollutant concentration was simulated by MODFLOW with random input variables and a new modified health risk assessment(MRA) model was established to analyze the level of "hazard". The limit concentration based on environmental-guideline and health risk due to manganese were systematically examined to obtain the general risk levels through a fuzzy rule base. The "vulnerability" and "hazard" were divided into five categories of "high", "medium-high", "medium", "low-medium" and "low", respectively. Then, "vulnerability" and "hazard" were firstly combined by integrated evaluation. Compared with the other two scenarios under deterministic methods, the risk obtained in the proposed system is higher. This research illustrated that ignoring of uncertainties in evaluation process might underestimate the risk level.

Enhancement of Cd Solubility and Bioavailability Induced by Straw Incorporation in Cd-Polluted Rice Soil

Of the factors affecting migration and bioavailability of toxic metals in heavy metal contaminated soil, DOC （dissolved organic carbon） provides binding sites for metal cations and reduces the fixation and adsorption of heavy metals by soil solid phase. Elevation of DOC level due to the direct incorporation of crop residues may lead to enhanced accumulation of toxic metals in crop body grown in polluted farmland. In this study, an incubation experiment and a pot experiment were conducted respectively to investigate the effects of wheat straw incorporation on DOC level, cadmium availability, and Cd accumulation in rice plant, and to establish the relation between Cd solubility and DOC level. A Cd-contaminated rice soil was used and incorporated with different rates （0%, 0.5% and 1%） of wheat straw in both experiments. Results showed that the change pattern of Cd in soil solution was very similar to that of DOC level. Wheat straw addition significantly elevated Cd and DOC level in soil solution while NH4NO3-extrated Cd was not affected. There existed a close linear correlation between soluble Cd and DOC level. Enhanced Cd accumulation in rice plant, grown in a Cd contaminated soil, induced by wheat straw incorporation was observed in this study.

Non-Point-Source Nitrogen and Phosphorus Loadings from a Small Watershed in the Three Gorges Reservoir Area

Non-point-source pollution has become a major threat to the water quality of the Three Gorges Reservoir(TGR);however,nutrient loadings from terrestrial sources are unclear due to a lack of in situ monitoring.A representative small watershed in the central part of the TGR area was selected to monitor the loss of nitrogen(N) and phosphorous(P) continuously along with the runoff from 2007 through 2009 to understand the exact sources and loadings.Results show that the non-point-source nitrogen and phosphorus comes mainly from the storm runoff from residential areas,citrus orchards and sloping croplands,which contributes up to 76% of the loadings in this watershed.Thus,a crucial measure for controlling non-point-source pollution is to intercept storm runoff from the three sources.Paddy fields provide a sink for non-point-source N and P by intercepting the runoff and sediment along with their different forms of nitrogen and phosphorus.The N and P removal efficiency by paddy fields from residential areas is within the range of 56% to 98%.Paddy fields are an important land-use option for reducing the non-point-source loading of N and P in the TGR area.

Genotoxic Effects in Mice Exposed to Radon Emissions in Indoor Conditions. Comparison between in utero and Neonatal Exposures

The purpose of this study was to develop a biological model to evaluate the genotoxic effects of natural emissions of Radon-222 and its decay products. To this aim, mice of the Swiss CD1 strain were exposed to Radon for different periods （adult life, early postnatal and in utero exposure） and two simple but accurate mutagenicity tests （Micronucleus test and the Comet assay） were applied to the peripheral blood of mice. The study was carried out in two small towns in Latium region--ltaly, where radon pollution is notoriously present due to the volcanic soils. One experiment was carried out in the cellar of a house in Ciampino （Rome） and two experiments were performed in an old cellar in Vetralla （Viterbo）. The results showed that in all mice groups exposed to natural emissions of radon and its decay products, the micronucleated erythrocytes frequency （ME） was significantly higher than that observed in the mice control. The single cell gel electrophoresis （Comet assay） was performed in lymphocytes of adult mice in the last experiment. The results for this test also show that DNA damage was higher than in the cells of the mice control and the cells of mice exposed for a shorter period of time. To confirm these findings, the single cell gel electrophoresis （Comet assay） was performed in lymphocytes of adult mice in the last experiment. Similarly, this result could be linked to a greater sensitivity of neonatal mice to radon emissions compared with intrauterine mice. Further investigations on the effects of radon and its decay products during the intrauterine life and the first neonatal period should be performed to better clarify its genotoxic activity.

Cadmium accumulation in different pakchoi cultivars and screening for pollution-safe cultivars

The selection and breeding of pollution-safe cultivars (PSCs) is a practicable and cost-effective approach to minimize the influx of heavy metal to the human food chain.In this study,both pot-culture and field experiments were conducted to identify and screen out cadmium pollution-safe cultivars (Cd-PSCs) from 50 pakchoi (Brassica rapa L.ssp.chinensis) cultivars for food safety.When treated with 1.0 or 2.5 mg/kg Cd,most of the pakchoi cultivars (>70%) showed greater or similar shoot biomass when compared with the control.This result indicates that pakchoi has a considerable tolerance to soil Cd stress.Cd concentrations in the shoot varied significantly (P<0.05) between cultivars:in two Cd treatments (1.0 and 2.5 mg/kg),the average values were 0.074 and 0.175 mg/kg fresh weight (FW),respectively.Cd concentrations in the shoots of 14 pakchoi cultivars were lower than 0.05 mg/kg FW.In pot-culture experiments,both enrichment factors (EFs) and translocation factors (TFs) of six pakchoi cultivars were lower than 1.0.The field studies further confirmed that the Hangzhouyoudonger,Aijiaoheiye 333,and Zaoshenghuajing cultivars are Cd-PSCs,and are therefore suitable for growth in low Cd-contaminated soils (≤1.2 mg/kg) without any risk to food safety.

Wheat Growth and Photosynthesis as Affected by Oxytetracycline as a Soil Contaminant

Extensive worldwide use of oxytetracycline （OTC）, a member of the tetracyclines, has resulted in its accumulation in soils, posing a potential risk to food production and safety. A pair of OTC-sensitive （Heyou 1） and OTC-tolerant （Yannong 21） wheat （Tritieum aestivum L.） cultivars was compared hydroponically at 0.01, 0.02, 0.04, and 0.08 mmol L-10TC in terms of wheat growth and photosynthesis. Biomass and shoot length decreased significantly with the addition of OTC, with the decreases in dry biomass and shoot length being 5.61%-13.75% and 3.33%-8.57% larger, respectively, for Heyou 1 than Yannong 21. Photosynthesis of Heyou 1 was suppressed by OTC as indicated by the significant decreases in photosynthetic rate （PN）, transpiration rate （TR）, and stomatal conductance （GS） and the significant increase in intercellular CO2 concentrations （CI）, at all OTC levels. Stomatal limitation （LS） and water use eftlciencies （WUE） of Heyou i also increased significantly, but not at 0.08 mmol L-10TC. However, photosynthesis of Yannong 21 was suppressed by OTC only at high OTC levels from 0.02 to 0.08 mmol L-1 as indicated by the decreases in PN, GS, TR, and LS; at 0.01 mmol L-10TC, PN, CI, GS, and TR significantly increased. It was noted that WUE of Yannong 21 was not affected by OTC addition. The results from this hydroponic test suggested that OTC had a potential risk to crop growth through inhibition of photosynthesis, requiring further confirmation with soil tests.