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Microorganisms play an important role in the biogeochemical cycle of antimony (Sb). However, specific microorganisms have not yet been identified that mediate Sb transport and fate in soil-plant systems. Arbuscular mycorrhizal fungi (AMF) form a mutualistic symbiosis with roots of over 90% of terrestrial plants. In the present study, we investigated the inoculation effects of Funneliformis mosseae , an AM fungus, on Sb accumulation and speciation in Cynodon dactylon (Bermuda grass) using Sb(V) spiked soil at 0, 500, and 1000 mg kg −1 treatment levels. Results indicated plant biomass was significantly increased by the AMF symbiosis. Compared to un-inoculated controls, mycorrhizal colonization significantly increased shoot and root Sb concentrations under all Sb treatment levels. Bioconcentration (BCF) and translocation (TF) factors were elevated by mycorrhizal colonization. Mycorrhizal colonization significantly increased exchangeable Sb concentrations and decreased carbonate-associated Sb in the rhizosphere under all Sb treatment levels. Moreover, Sb(III) percentages relative to total Sb were significantly lower in mycorrhizal plants. These results suggested AMF likely inhibited Sb(V) to Sb(III) reduction processes, and thereby alleviated Sb toxicity in host plants. These findings demonstrated AMF serve an important role in Sb transport and fate in soil–plant systems.

The residues of organochlorine pesticides (OCPs) in surface waters from Meiliang Bay, Gonghu Bay, and Xukou Bay of Lake Taihu, China, were investigated, and their ecological risks were assessed using the risk quotient method and probabilistic risk assessment. Environmental concentrations of OCPs in surface water of these bays were relatively lower compared with other rivers or lakes in China. Calculation of risk quotient associated with taxonomic groups indicates moderate ecological risks from OCPs for crustaceans and insects in these bays, while the ecological risks were low for fish and negligible for phytoplankton. The ecological risk quotients associated with individual OCPs were lower than 0.01 in these bays, suggesting a negligible risk to aquatic organisms. Ecological risk from α-HCH was relatively lower compared with DDTs, endosulfans, and γ-HCH. The combined ecological risks were evaluated using probabilistic risk assessment for only eight OCPs owing to a lack of available toxicity data ...

A total of thirty-three surface water samples were collected from Meiliang Bay, Gonghu Bay and Xukou Bay of Lake Taihu, and analyzed for synthetic musks, including 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[γ]-2-benzopyrane (HHCB), 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN), 1-tert-butyl-3,5-dimethyl-2,5-dinitro-4-acetylbenzene (MK) and 1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene (MX). Ecological risks of these compounds were characterized by hazard quotient (HQ) method due to a lack of sufficient available toxicity data of synthetic musks. HHCB was the main synthetic musk detected in Lake Taihu, followed by AHTN, MK, and MX. The risk assessment results indicate that low ecological risks were posed by HHCB and total synthetic musks, and even lower risks posed by other synthetic musks in the worst case; much lower ecological risks were caused by both individual and total synthetic musks in the general case. The combined ecological risk from total synthetic musks calculation suggests that the combined ecological risk from all four synthetic musks was expected to be slightly higher than for the individual musks due to their joint action. The HQ spatial distribution maps show that several hot-spot areas were mainly around the river inlets to Lake Taihu, indicating that synthetic musks may be transported to Lake Taihu with municipal sewage and industrial wastewater from surrounding areas. However, the ecological risks in hot-spot areas posed by individual and total synthetic musks were still acceptable.

Thirteen sediment core samples (0–10 cm) were taken from the seven lakes in the middle and lower reaches of the Yangtze River to determine the contents and distributions of organic phosphorus (P) fractions in the sediments of the shallow lakes in the area. The organic P fractions in the sediments were in the order of moderately labile organic P (MLOP) > moderately resistant organic P (MROP) > highly resistant organic P (HROP) > labile organic P (LOP), with average proportional ratios of 13.2:2.8:1.3:1.0. LOP, MLOP, and MROP were signiflcantly related to the contents of total organic carbon (TOC), water-soluble P (WSP), algal-available P (AAP), NaHCO 3 -extractable P (Olsen-P), total P (TP), organic P (OP), and inorganic P (IP). However, HROP was signiflcantly related to OP and weakly correlated with TOC, WSP, AAP, Olsen-P, TP or IP. This suggested that organic P, especially LOP and MLOP in sediments, deserved even greater attention than IP in regards to lake eutrophication. In terms of organic P, sediments were more hazardous than soils in lake eutrophication. Although OP concentrations were higher in moderately polluted sediment than those in heavily polluted sediment, LOP and MLOP were higher in the heavily polluted sediment, which indicated that heavily polluted sediment was more hazardous than moderately polluted sediment in lake eutrophication.

A method of ultra-performance liquid chomatography tandam mass spectrometry(UPLC-MS/MS) combined with solid-phase extraction (SPE) has been developed for simultaneous analysis of 18 glucocorticoids in surface water. The analytes were first enriched and purified through a HLB cartridge, and eluted with acetonitrile/ethyl acetate (1:1, V/V), then detected by UPLC-MS/MS. The detection used gradient elution process with methanol and 0. 1% formic acid/water (V/V) as the mobile phase to achieve baseline separations of these 18 analytes. The linear range was 1. 0-1 000 µg.L-1. The method detection limits (MDLs) were 0. 10-1. 0 ng.L-1 except for cortisone acetate and cortisol acetate(10 ng.L-1) with overall mean recoveries of 65% - 108% in surface water. Application of this method for 5 surface waters from Beijing area showed that 8 glucocorticoids were detected with the concentration range of 0. 20-476 ng.L-1. Triamcinolone, triamcinolone acetonide, cortisol acetate and clobetasol propionate were detected for the first time in surface water samples, suggesting that this method is efficient for real sample analysis.

Samples of sediments, interstitial water and overlying water were collected monthly under temperature-controlled conditions to determine the effects of sediment types on the alkaline phosphatase activity (APA) in lake systems. The relationship between the total alkaline phosphatase activity (TAPA) and soluble reactive phosphorus (SRP) concentration also was examined. The study results indicate the variations of TAPA in the overlying water, and the interstitial water in different layers from different sediments was similar over time. They were influenced not only by the phosphate concentrations, but also were correlated with submerged plant and phytoplankton biomass. The direct effects of the sediment types on the APA were not readily obvious. Although the higher APA in sediment was probably responsible for the enzymatic response to the characteristics of sediments, other factors (e.g. growth of submerged plants and phytoplankton) also should be considered. The peak of the maximum velocity of the enzyme reactions (Vmax) at deeper sediment layers suggests another stratum in which the enzymatically mediated phosphorus regeneration was active. This finding contributes to our understanding of phosphorus cycling in lake sediments.

The sediment characteristics, different phosphorus (P) fraction concentrations and the effect of pH on P release were investigated in a shallow eutrophic lake in China. The total phosphorus (TP) concentrations in the sediments ranged greatly from 420 to 3408 mg kg(-1) and inorganic P (IP) was the main P fraction. For the heavily eutrophic sediment, IP mainly consisted of NaOH-P; while for the mesotrophic sediments, IP mainly consisted of HCl-P. The rate of P release decreased as pH increased from 2 to 6. But it increased as pH increased from 8 to 12. It is suggested that high pH promoted the release of NaOH-P, and low pH promoted the release of HCl-P, and there was no P release occurring in the neutral condition.

Adsorption of alkaline phosphatase (APase) on minerals (goethite, montmorillonite) and sediments from Taihu Lake was studied. However, the concentration of alkaline phosphatase in the supernatant cannot be analyzed by the adsorption at 280 nm due to that the UV spectroscopy was changed. Quantitative analysis of alkaline phosphatase in the supernatant by the absorption peak (252-305 nm) integration method of UV spectroscopy was developed. This method determined the concentrations of alkaline phosphatase well. Compared to the results of Bradford, the absorption peak integration method can determine the concentrations of supernatant fast, conveniently, and accurately. This method can also be applied to other protein solution analysis and similar experiments. The drawbacks of traditional single wavelength method (280nm) were overcome to some extent based on the method of absorption peak integration.

Bisphenol A (BPA) has many toxic effects on aquatic organisms, of which the most obvious effect is the estrogenic effect. The data collected in the study were divided into two parts, based on the response of the tested organisms to the estrogenic effects of BPA and their exposed time, and the risk of BPA to Chinese aquatic water was assessed by using quotient method, quotient exponent and probability method, safety threshold value method and joint probability risk assessment, respectively. Similar results were derived from the above four methods. Aquatic organisms were more sensitive to the estrogenic effects of BPA than other toxic effects. The results of risk assessment from safety threshold value method were more accurate and confident than the other three methods. Using the chronic data of BPA's estrogenic effect on tested organisms as the endpoint for risk assessment in safety threshold value method, it was found that in 64.70% of the Chinese freshwaters more than 5% of aquatic organisms were affected by the estrogenic toxicity of BPA, and the maximum allowable concentration of BPA was 15.72 ng x L(-1). Using the acute data of such effects as endpoint in safety threshold value method, in about 20.43% volume of the Chinese freshwaters more than 5% of aquatic organisms were affected by the estrogenic toxicity of BPA, and the maximum allowable concentration was 2.24 x 10(2) ng x L(-1).

Probabilistic approaches, such as Monte Carlo Sampling (MCS) and Latin Hypercube Sampling (LHS), and non-probabilistic approaches, such as interval analysis, fuzzy set theory and variance propagation, were used to characterize uncertainties associated with risk assessment of sigma PAH8 in surface water of Taihu Lake. The results from MCS and LHS were represented by probability distributions of hazard quotients of sigma PAH8 in surface waters of Taihu Lake. The probabilistic distribution of hazard quotient were obtained from the results of MCS and LHS based on probabilistic theory, which indicated that the confidence intervals of hazard quotient at 90% confidence level were in the range of 0.000 18-0.89 and 0.000 17-0.92, with the mean of 0.37 and 0.35, respectively. In addition, the probabilities that the hazard quotients from MCS and LHS exceed the threshold of 1 were 9.71% and 9.68%, respectively. The sensitivity analysis suggested the toxicity data contributed the most to the resulting distribution of quotients. The hazard quotient of sigma PAH8 to aquatic organisms ranged from 0.000 17 to 0.99 using interval analysis. The confidence interval was (0.001 5, 0.016 3) at the 90% confidence level calculated using fuzzy set theory, and the confidence interval was (0.000 16, 0.88) at the 90% confidence level based on the variance propagation. These results indicated that the ecological risk of sigma PAH8 to aquatic organisms were low. Each method has its own set of advantages and limitations, which was based on different theory; therefore, the appropriate method should be selected on a case-by-case to quantify the effects of uncertainties on the ecological risk assessment. Approach based on the probabilistic theory was selected as the most appropriate method to assess the risk of sigma PAH8 in surface water of Taihu Lake, which provided an important scientific foundation of risk management and control for organic pollutants in water.

The USEPA 16 priority pollutant dominated polycyclic aromatic hydrocarbons (PAHs) in the surface river sediments of Sichuan Province and Chongqing City in southwest China were determined using GC-MS. The result showed the content of PAHs in the sediment ranged from 48.2 ng/g to 723.1 ng/g, with an average value of 276.1 ng/g. Among which, the maximum content was found in Shimenzi of Yangtze River, the minimum content was found in Baiqing of Fujiang River. The content order of PAHs in the sediments followed Yangtze River (358.6 ng/g)Minjiang River (322.2 ng/g)Tuojiang River (292.7 ng/g)Qujiang River (260.6 ng/g)Jialing River (240.2 ng/g)Fujiang River (82.4 ng/g). The vertical profiles of c(An)/c(An + Phe), c(FlA)/c(FlA + Pyr) and c(InP)/c (InP + BghiP) suggested the PAHs in this zone were mainly originated from pyrogenic source, the main sources of PAHs were petroleum combustion, biomass combustion, and coal burning. Risk assessment suggested that the PAHs in the sediment of this zone had no significantly biological impairment and low toxicological risk.

In order to reconstruct the chronology of 2,2-his (4-Chlorophenyl)-1,1,1-trichloroethane (DDT) input into the Hongfeng reservoir and assess the pollution issues, the temporal distribution of DDT in sediment core from Hongfeng reservoir was measured using GC/MS method, and the possible sources and potential risk assessment also had been identified. The DDTs (sum of p,p'- and o,p'-DDT, DDE and DDD) in sediment core were ranged from 7.6 to 23.7 ng/g, and roughly, ever decreased from the bottom to the surface sediment. In detail, a sharp decline of DDTs concentration in sediment was found from 1981 to 1983, followed by a tardy decrease trend to the present. The DDTs in sediment were mainly composed of p,p'-DDTs (sum of p,p'-DDT, DDE and DDD). The ratio of p,p'-DDTs to o,p'-DDTs (sum of o,p'-DDT, DDE and DDD) ranged from 5.1 to 8.4, which suggests that the DDTs in sediment were chiefly originated from the technical DDT. Meanwhile, the DDTs in sediments were dominated by the metabolites of DDT (DDD and DDE) and the ratio of DDT/(DDD + DDE) were between 0.31 and 0.84, indicating the DDTs in sediment were mostly stemmed from the historical usage. Besides, the vertical profile of the ratios of DDT/( DDD + DDE) and DDE/DDD indicate that possible usage of technical DDT still occurred in the drainage area of Hongfeng reservoir around 1990, although the usage of technical DDT in agriculture has been banned in 1983. The residue levels of DDE, DDD, DDT, and DDTs in surface sediment from Hongfeng reservoir were all between ERL and ERM, suggesting potential risk could occur, and the contamination of DDT in Hongfeng reservoir deserving more concerns.

The temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was measured in sediment core from Miyun reservoir, and the possible sources and the potential risk assessment also have been identified. The aim of the present work is to understand the temporal trend of PAHs in Miyun reservoir recently. The concentrations of sigma PAH16 in sediment ranged from 618.5 ng/g to 1087.9 ng/g, and roughly, increased continuously from the bottom (16 cm under the surface) to the surface sediment. The PAHs in sediment core were mainly composed of phenanthrene and fluorene. The concentrations of phenanthrene and fluorene in sediment core were 236.1-417.9 ng/g and 91-130.8 ng/g, respectively. Both of them accounted for 47.2%-58.1% of the sigma PAH16 in sediments. Nevertheless, high-rings aromatic hydrocarbons (5-6 rings) were increased steadily in recent years. PAHs compositional profile indicated that the main source of PAHs was originated from the combustion of coal and biomass. However, the vertical profiles of Flu/Flu + Pyr and INP/INP + BghiP ratios suggested that the vehicles emission was increased very recently. Risk assessment suggested that PAHs in sediment from Miyun reservoir was no significant biological impairment, and low toxicological risk of PAHs was found up to now.

The concentration levels of antimony, arsenic and mercury in human hair collected from Xikuangshan antimony mining area and Guiyang City were determined by hydride generation-atomic fluorescence spectrometry after having been digested by nitric acid and perchloric acid. The contents of Sb, As and Hg are 15.9, 4.21, 1.79 microg/g in the samples from Xikuangshan antimony mining area and 0.532, 0.280, 0.338 microg/g in the samples from Guiyang City respectively. The contents of Sb, As and Hg in human hair of Xikuangshan antimony area are much higher than those of Guiyang City. The independent-samples t-test shows that there are no marked differences in the contents of Sb and As between male and female hair samples from both Xikuangshan antimony mining area and Guiyang City (p0.05), while Hg contents in male hair are apparently higher than those in female hair from Guiyang City (por = 0.05). There is positive correlation observed between As and Sb, as well as between As and Hg, while Sb is weakly correlated with Hg (por = 0.01). These results show that the heavy metals (Sb, As and Hg) in antimony mining area may significantly affect human health than in the un-mining areas.

The characteristics of organic matter in different extractions of phosphorus forms in the surface sediments (0-10 cm) from three different regions of north part of Taihu Lake were investigated using the combination of high-performance size-exclusion chromatography (HPSEC), three-dimensional excitation/emission matrix (3DEEM) fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR) and elemental analysis, and the relationship between organic matter and phosphorus was also discussed. The results show that the concentrations of total phosphorus in sediments coincide with the corresponding trophic level of overlying water. The atomic ratios of C/N (8.5-11.9) and C/P (188.5-256.6) indicate that organic matter in these sediments originated mainly from a lacustrine authigenic source, with minor terrestrial contribution. The molecular weight distribution and fluorescence spectroscopy of organic matter varied with different extractions, whereas the differences were not significant between sampling sites. The rank order of the molecular weight of organic matter in three kinds of extractions was: HClNaOHNaHCO3, with M(w) and M(n) ranging from 4 983 to 5 873 and 3 642 to 5 065, 3 628 to 4 198 and 2 334 to 2 616, 3 282 to 3 512 and 2 249 to 2 380, respectively. These properties may suggest the composition of organic phosphorus and its bioavailability differs in different extractions. The fulvic acid-like (E(x)//E(m) = 230-260 nm/360-470 nm of peak A or E(x)/E(m) = 290-320 nm/390-460 nm of peak C) fluorophore was predominant in these extractions, while protein-like (E(x)/E(m) = 275-280 nm/340-360 nm of peak B and E(x)/ E(m) = 225 nm/330-350 nm of peak D) and humic acid-like (E(x)/E(m) = 360-375 nm/460-470 nm of peak E) fluorophores were observed in NaHCO3 and HCl extractions individually. Possibly indicates that the differences in the composition of organic matter and its decomposition in the sediment from Taihu Lake are subjected to resuspension. Moreover, the absorption of sedimentary humic acid from 1059 to 1 082 cm(-1) in the FTIR suggests that orthophosphate occurred in humic matrix.

The combination of ultrafiltration, three-dimensional excitation/emission matrix (3DEEM) fluorescence spectroscopy and high-performance size-exclusion chromatography (HPSEC) was used to characterize the molecular weight distribution properties of different fluorescence materials, further revealing the differences in the sources and components. Dissolved organic matter (DOM) from different lakes fractionated by ultrafiltration with a nominal 1,000 molecular weight cut-off regenerated cellulose membrane, then 3DEEM spectrophotometry and HPSEC were applied to investigate the characteristics of high molecular weight materials in retentate and low molecular weight materials in permeate. The result indicated that the flulvic acid-like (Ex/Em approximately equal to 260 nm/450 nm of peak A and Ex/Em approximately equal to 320 nm/439 nm of peak C) and protein-like (Ex/Em approximately equal to 275 nm/312 nm of peak B and Ex/Em approximately equal to 220 nm/308 nm of peak D) fluorophores in permeate were detected after ultrafiltration which is covered by high absorbing peak of humic-like (Ex/Em approximately equal to 360 nm/462 nm of peak E) fluorescence fluorophores in the original Shennonajia bog water, Hubei province. They permeated the membrane because of their low molecular weight distribution properties. The content of autochthonous protein-like (Ex/Em approximately equal to 280 nm/334 nm of peak B and Ex/Em approximately equal to 225 nm/328 nm of peak D) component was too low to be measured by high-sensitivity fluorescence spectrophotometer in the original water of Lake Hongfeng, Guizhou province. But they can be concentrated attribute to their high molecular weight distribution properties. The 3DEEM fluorescence spectroscopy of retentate exhibited evident protein-like fluorophores. Moreover, there had obviously difference in molecular weight between different sources of fulvic acid-like and protein-like components. It has been shown that the molecular weight distribution of autochthonous protein-like matter in Hongfeng lake is larger than allochthonous protein-like matter in Aha lake, Guizhou province. One was retained by membrane and another was permeated. Therefore, these techniques together will offer direct and convenient qualitative information about DOM in lake waters.

Our previous study demonstrated that FSH-induced immediate Ca(2+) influx in rat Sertoli cells (SCs) is mediated by the Galphah/phospholipase C-delta1 (PLC-delta1) signaling pathway. As to which Ca(2+) channel is responsible for such Ca(2+) influx was not understood. In this study, thapsigargin triggered an in-store calcium release and evoked a 1.5-fold elevation of intracellular Ca(2+) in Ca(2+)-free media, whereas FSH exhibited no effect. The readdition of CaCl(2) (2.5 mm) to FSH-pretreated or thapsigargin-sensitized SCs in Ca(2+)-free media immediately elicited a rapid Ca(2+) influx or a 2-fold increase of second intracellular Ca(2+) elevation, respectively. The addition of Ca(2+) chelator EGTA (0.2 mm) reduced the FSH-induced elevation of intracellular Ca(2+) in SCs incubated with CaCl(2). However, pretreatment with dantrolene (25 microM), which inhibits in-store calcium release, did not affect the FSH-induced elevation of intracellular Ca(2+). NiCl(2) (10 microM), a T-type calcium channel blocker, abolished the FSH-induced SC Ca(2+) influx. Furthermore, mibefradil (10 and 100 microm), another specific blocker for T-type Ca(2+) channels, dose-dependently suppressed the FSH-induced Ca(2+) influx. In contrast, nifedipine (10 and 50 microm) or omega-conotoxin GVIA (100 and 500 nm), blocker of L- or N-type Ca(2+) channels, respectively, did not affect the FSH-induced SC Ca(2+) influx. On the other hand, FSH-induced Ca(2+) influx was significantly reduced by pretreatment of SCs with myristoylated synthetic peptide (0.1 and 1 microm) of PLC-delta1 fragment TIPWNSLKQGYRHVHLL but not affected by 2',5'-dideoxyadenosine (3 and 15 microm), a selective inhibitor of adenylate cyclase. In conclusion, the FSH-induced Galphah/PLC-delta1 pathway-dependent Ca(2+) influx of rat SCs is mediated by T-type Ca(2+) channels and independent of in-store calcium release.

Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) are rarely measured together when studying dissolved organic matter (DOM) in lake water. DOC and DON concentrations were measured for a Karst plateau lake--Hongfeng Lake water for nearly two years. Profile characteristics and seasonal variation of dissolved organic matter were studied, and influencing factors were discussed. The results indicate that DOC concentration ranges from 1.60 mg x L(-1) to 3.08 mg x L(-1), DON ranges from 0.10 mg x L(-1) to 0.37 mg x L(-1) during studying period. DOC and DON concentrations change little from upper layer water to bottom during mixed periods, but show a general tendency for an upward increase during stratification periods. DOC concentration in the surface layer water (0-2 meters or 3 meters) of Hongfeng Lake is greatest from late spring to early summer or in summer, DON concentration is a little higher from late spring to early summer. Comparing the seasonal variation trend of DOC with that of chla and rainfall we draw a conclusion that the bioactivity of algae and DOM input from the watershed directly result in the seasonal variation mode of DOM in surface layer water. The C/N ratio of DOM generally increases with the increase of depth, but this trend changes at HF-S site in summer. At the depth of 12m, DOC and DON concentrations increase with the increase of depth; the C/N ratio of DOM decreases from 18.1 at the depth of 12 m to 14.9 at the depth of 14 m, and decreases continually with the increase of depth. A possible cause is the decomposition of POM, which forms an autochthonous source of DOM.

Three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) was used to investigate the effect of sunlight irradiation on the fluorescence properties of dissolved organic matter (DOM) from Lake Hongfeng and Nanming River waters and a commercial fluka humic acid (FHA). The results show that the DOM samples and FHA fluorescence properties changed under sunlight irradiation. Interestingly, the photodegradation characteristics were different between aquatic DOM and FHA. The fluorescence intensity of the apparent peaks A, B and C of lake and river water DOM decreased with sunlight irradiation. The initial 3DEEM of Fluka HA had only one fluorescence peak at lamda ex / lamda em = 275/500 nm, while two fluorescence peaks occurred at lamda ex / lamda em = 245/450 nm and 310/450 nm, respectively, after sunlight irradiation. lamda ex and lamda maxima of DOM decreased during 7 days of sunlight irradiation. Changes in r(A, C) of DOM and FHA with sunlight irradiation time suggest that fluorescence peaks A and C had different fluorescence loss rates, while peak C fluorophores were more susceptible to sunlight irradiation. FHA appeared to be less susceptible to photodegradation, and its r(A, C) remained almost the same before and after sunlight irradiation.

Three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) was applied to characterize the fluorescence properties of dissolved organic matter (DOM) in lakes, rivers, streams, and ground waters. The results showed that the 3DEEM of DOM in aquatic environments mainly have four fluorescence peaks: peak A and C was referred to as fulvic-like fluorescence, and peak B and D was referred to as protein-like fluorescence. Results of river water DOM typically showed strong fulvic-like fluorescence. Polluted river waters often showed strong protein-like fluorescence. Four peaks were also found in the 3DEEM of lake DOM, which can origin from terrestrial runoff or from sources within the lakes. In Lake Baihua, strong protein-like fluorescence was found owing to the pollution by municipal wastewaters. Groundwater DOM has relatively lower DOC concentrations at 0.56-0.85 mg x L(-1) and is characterized by fulvic-like fluorescence only if it was polluted by municipal wastewaters, and then it has strong protein-like fluorescence. The authors demonstrate that for all DOM samples, fluorescence intensity at peak C and absorption at 254 nm both showed a strong correlation with DOC concentrations (r2 = 0.82 and 0.95, respectively). Also a strong linear correlation between UV-fulvic-like fluorescence and visible fulvic-like fluorescence was found (r2 = 0.96). The fulvic-like fluorescence at peak A and C varied in accordance to each other with the pH of the DOM samples, and the maximum fluorescence occurred at pH 10, while the maximum value of protein-like fluorescence (peak B) occurred at pH around 8.5.

With the development of fluorescence technique, three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) was widely applied to characterize the nature of dissolved organic matter (DOM) in natural waters since the last decade. 3DEEM and fluorescence quenching titration were used to study the interaction between Hg(II) and DOM. The results show that a general decrease in intensity for individual peak A, B and C was found as concentrations of Hg(II) increased. pH is the main parameter that strongly influences the Hg(II)-DOM complexation. The addition of Cl- ion to the Hg(II)-DOM system caused an increase in fluorescence intensity. The results also show that the addition of Ca(II) solution strongly enhanced the fluorescence intensity for humic-like fluorescence, while the protein-like fluorescence only slightly enhanced. On the contrary, no fluorescence enhancement was found in the Hg(II)-DOM system after the addition of Mg(II) ion. A decrease in fluorescence emission intensity was found after the addition of Cu(II) ion to the Hg(II)-DOM solution.

Exogenous agents and endogenous processes, such as reactive oxygen species (ROS) can induce base oxidation and DNA lesions. One of the most severe DNA lesions is the double-strand break (DSB). There are several repair systems to fix the resulting DNA lesions to prevent error copies of genetic information to be carried to daughter cells. Oxidative stress is an important factor to induce DNA damage during normal cellular metabolism. In this study, we wanted to use lung cancer cells, CL1-0 and CL1-5 cells, which have differential invasiveness ability to characterize DNA repair function. Hydrogen peroxide (H2O2) was treated in lung adenocarcinoma cells to induced DNA DSB. By using immunoflurecence microscope, we found that CL1-5 had more gamma-H2AX foci (DNA DSB marker) and ROS accumulation than CL1-0 post both 1 mM and 5 mM H2O2 treatment. Moreover, CL1-0 had a tight G2/M checkpoint and has a longer G2 arrest after H2O2 treatment, but not found in CL1-5. In addition, increasing sub-G1 population (apoptotic cells) was found in H2O2-treated CL1-5 but less in CL1-0. Furthermore, phosphorylated-Akt (S473) was decreased in CL1-5, In contrast, phosphorylated-ATM (S1981) and Chk2 were increased after 5 mM H2O2 treatment for 90 min. In addition, the level of GSH was persistently lower at the steady state and post H2O2 treatment in CL1-5 by LC-MS/MS analysis. Besides, the apoptotic cells were decreased but no differences in CL1-0 while supplement reduced-GSH before H2O2 treatment. We therefore hypothesize that there are different processes on dealing with ROS scavenging post oxidative stress between CL1-0 and CL1-5. Taken together, using hydrogen peroxide for treating two lung cancer cell lines seem to have different DNA repair function to regulate cellular function. In the following experiments, the activities of antioxidant enzymes, superoxide dismutase (SOD), catalase as well as glutathione peroxidase (GPx) post oxidative stress in CL1-0 and CL1-5 will be determined. Moreover, we will examine the level of GSH in different tumor cell lines to investigate whether GSH involved in tumor invasion ability. Citation Format: Feng- Chang Wu, Yu-Fen Lin, Liang-Chuan Lai, Eric Y Chuang, Mong-Hsun Tsai. To study DNA repair function of two closely related human lung adenocarcinoma cell lines, CL1-0 and CL1-5. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2914. doi:10.1158/1538-7445.AM2013-2914 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.