Linear QSAR Regression Models for the Prediction of Bioconcentration Factors of Chloroanilines in Fish by Density Functional Theory

Density functional theory（DFT）-B3LYP level with the 6-311G＊＊（d,p） basis set was used to calculate a set of molecular quantum chemical descriptors of 12 chloroanilines. Quantitative structure-activity relationship（QSAR） models of the bioconcentration factors（BCF） of the anilines in fish were established using some of the following calculated descriptors： EHOMO, ENHOMO, ELUMO, ENLUMO, ΔE1（= ELUMO- EHOMO）, ΔE2（= ENLUMO- ENHOMO）, dipole moment（μ）, molecular volume（V）, vibrational energy of 0 K（Ev）, thermodynamic energy（E）, heat capacity（Cv）, entropy（Sm） and the charge of benzene ring（Qph）. Using the variable selection and leaps-and-bounds regression, the quantum chemical descriptors derived directly from the molecular structures were employed to develop a linear QSAR model between the bioconcentration factors（BCF） and two descriptors（Sm, ENHOMO） of 12 chloroanilines. Statistically, the most significant one is a two-parameter linear equation with the correlation coefficient（R^2） of 0.981 and cross-validated correlation coefficient（Rcv^2） of 0.967. The established QSAR model has good stability and predictability based on the results from Rcv2 of leave-one-out cross-validation, AIC, FIT and tα/2. The quantum chemical analyses were performed from two aspects of frontier molecular orbital and entropy. The results show that two structural describers are crucial to the bioconcentration activity of chloroanilines.

Seasonal bioconcentration of heavy metals in Onchidium struma(Gastropoda:Pulmonata)from Chongming Island,the Yangtze Estuary,China

The seasonal concentration changes of selected heavy metal Cd, Cr, Cu, Fe, Mn, Pb, and Zn in five tissues of marine gastropod Onchidium struma were studied in the Chongming Island, the Yangtze Estuary in April 2007, July 2006, September 2006, and November 2006, respectively. The results demonstrated that the bioconcentration factor of Cu （biomass/water） in all selected tissues was about 104 magnitudes, Fe and Cd were 103, Zn was 102, and Mn, Pb, and Cr were 101. Hepatopancreas was proven to be the dominant storage tissue of Cr, Cu, Mn, and Zn, whereas Fe and Pb were mainly stored in muscle and digenetic gland, and Cd was stored in vitelline gland and albumen gland. Additionally, it was found that Cu, Fe, Mn, and Zn were concentrated significantly by O. struma （whole-body） in summer or autumn, and Cd, Cr, and Pb increased slightly in spring and winter. Furthermore, the bioconcentration of Cr was nearly 2-fold higher and Zn was 1.6-fold higher in the water compared with the Water Quality Standard for Fisheries. With view of excessive amount of Pb, Cd, and Cu according to seafood standard, the consumption of O. struma might have the risk of health hazard.

Bioconcentration of polycyclic aromatic hydrocarbons in roots of three mangrove species in Jiulong River Estuary

The polycyclic aromatic hydrocarbons(PAHs) concentrations were determined in the root of three mangrove species(Kandelia candel, Avicennia marina and Bruguiera gymnorrhiza) and their growing environment(sediment) in mangrove wetlands of Jiulong River Estuary, Fujian, China. The total PAHs(16 parent PAHs) in mangrove sediments ranged from 193.44 to 270.53 ng/g dw, with a mean value of 231.76±31.78 ng/g dw. Compared with other mangrove and coastal marine sediments, the PAHs concentrations of all the sampling areas in this study were at relatively lower level. The total PAHs(13 parent PAHs) values varied from 30.83 to 62.73 ng/g dw in mangrove roots. Benzo[a]pyrene(five-ring), fluoranthene(four-ring) and pyrene(four-ring) dominated in mangrove sediments. Based on ratios of phenathrene/anthracene, fluoranthene/pyrene and fluoranthene/pyrene + fluoranthene, the main possible sources of surface sediment PAHs were identified as grass, wood or coal combustion for mangrove wetlands of Jiulong River Estuary. Naphthalene(two-ring) and phenathrene(three-ring) were the most abundant compounds in mangrove roots. Sediment-to-vegetation bioconcentration factors(BCF SV s) were calculated and their relationships with PAHs' physico-chemical properties were investigated. The average BCF SV s of PAHs for three mangrove species roots were almost all under the level of 1 except for naphthalene. Good linear relationship between BCF SV values for mangrove roots and PAHs water solubility, octanol-water partitioning coefficients was derived in present study. The solubility and the octanol-water partition coefficient were proved to be good predictors for the accumulation of PAHs in mangrove roots, respectively.

Estimation and Prediction of Bioconcentration Factors of Nonionic Organic Chemicals in Fish by Electrotopological State Indices and Structural Parameter

Based on the characteristics of atom types, Hall＇s electrotopological state indices （En） are calculated for 165 nonionic organic compounds. On the basis of the characteristics of substituent and conjugated matrix, a novel molecular structure parameter （G） is defined and calculated for 165 molecules in this paper. En and G show good structural selectivity for organic molecules. G, a satisfactory relationship between bioconcentration factor （BCF） and En, is expressed as： 1gBCF = -0.283 ＋ 1.246G ＋ 0.079E42 ＋ 0.351E9- 0.063E17 （n＇ = 122, R = 0.967, F = 425.636, s = 0.394）, which could provide estimation and prediction for the lgBCF of nonionic organic chemicals. Furthermore, the model is examined to validate overall robustness with Jackknife tests, and the independent variables in model do not exist cross correlation with VIF. All these regression results show that the new parameter G and electrotopological state index have good rationality and efficiency. It is concluded that the En and G will be used widely in quantitative structure-property/activity relationship （QSPR/QSAR） research.

Experimental Study on Diflubenzuron: Degradation in Freshwater and Bioconcentration in Mosquitofish Following Chronic Exposure

Diflubenzuron (DFB, trade name dimilin 25 WP) is a chitin synthesis inhibitor widely used against forest insect pests in Algeria. Prior to implementation of these products as chemical agents for mosquito control, knowledge on their potential effects on non-target organisms and its behaviour in water are needed. Therefore, the present study was focused on DFB and aimed to use an HPLC procedure developed previously in order to obtain information on its degradation in freshwater and its bioconcentration in adult females of the fish Gambusia affinis (Cyprinodondiformes, Poeciliidae), which is one of the best candidates for biological control programs against mosquitoes. The adult females were exposed to dimilin (initial concentration 312 ng a.i./ml) for 28 days and residues analysis determined at different exposure times (0, 7, 14, 21 and 28 days). The concentration of DFB in freshwater decreased with exposure time while the amount of residues detected at the surface of the fish body increased progressively to reach a maximum at day 14 (162.7 ± 14.0 ng/fish) and declined thereafter during the exposure period. In addition, DFB incorporation into body increased with decreasing DFB concentration in water at each exposure time. The following average distribution was noted at the end of experiment (28 days): about 33% of the applied concentration was detected on the surface of fish body and was recovered by simple rinsing, and about 67% was found inside the fish body. A degradation in water and surface of fish occurred starting day 14 during the experimental period. Thus, about 40% of the initial concentration was degraded in freshwater after 28 days. The results are discussed to develop a better understanding of the degradation of dimilin in water and their potential effect on non-target organisms for its application for controlling mosquito.

Selected Heavy Metals in Water and Sediments and Their Bioconcentrations in Plant (<i>Polygonum pulchrum</i>) in Sosiani River, Uasin Gishu County, Kenya

Heavy metals’ availability and accumulation along the food chain pose public health risks. Water, sediment and plant samples were collected from selected sampling sites along Sosiani River, Uasin Gishu County, Kenya. The sediment and plant samples were dried in the oven at 50°C to constant weight and digested in a mixture of acids according to standard procedures. The water samples, sediments and plants digests were analyzed for selected heavy metals using Atomic Absorption Spectrophotometer (model AAS Variant 200). The site near the Moi Teaching and Referral Hospital (MTRH) had the highest total heavy metals concentration in water: Cu (0.18 ± 0.04 ppm);Pb (0.46 ± 0.09 ppm) and Zn (0.70 ± 0.22 ppm) and sediments: Cu (1.62 ± 0.14 ppm);Pb (1.27 ± 0.17 ppm) and Zn (6.73 ± 0.88 ppm) respectively. Fractionation of heavy metals in sediments showed low percentage solubility (Cu 9.3%;Pb 8.5%;Zn 4.2%). Concentration of zinc in studied plants was highest (3.60 ± 0.63 ppm), with a bioconcentration factor of 15.1 based on soluble zinc fraction. This indicates that conditions in the study area show preferential zinc metal uptake in plants and may lead to accumulation in exposed plants posing Zn exposure risks along the food chain. Suggestions are made for monitoring of heavy metals in food crops and aquatic organisms such as fish in the study area.

Bioconcentration kinetics of PCBs in various parts of the lifecycle of the tadpoles Xenopus laevis

Polychlorinated biphenyls （PCBs） in Xenopus laevis have been reported only for a few congeners. Additionally, there is very little information on the ability of Xenopus laevis to bioconcentrate PCBs. To address these issues, the tadpole Xenopus laevis was exposed to Aroclor 1254 mixtures in water at room temperature for 110 d followed by an additional 110 d of nonspiked PCBs in the water for the control group. During the whole process, bioconcentration factors （BCFs） of PCBs ranged from 1180 to 15670. For most PCB congeners, the highest and lowest bioconcentrations of the kinetic curves were found to be remarkably simultaneous, respectively. All 141 PCB congeners under the same experimental conditions had no linear correlation on the lgBCF versus lgKow relationship. The relationship between lgBCFs and lgKow followed a parabolic pattern indicative of selective bioconcentration, suggesting that the kinetic curves of the PCB congeners observed in the lifecycle of the tadpoles may be concentrated due to the amphibian special species and internal metabolism. In contrast, lgBCFs for PCBs were inversely related to lgKow, suggesting that a metabolism of the higher Kow PCB congeners occurred. These results support the author＇s conclusion that the tadpole Xenopus laevis plays major roles in the bioconcentration of PCB congeners, and demonstrated that the exposure kinetic curves of PCB congeners are complex. Besides the amphibian metamorphous development, the lifecycle of the tadpole Xenopus laevis also may be of importance in determining the bioconcentration of PCB congeners.

BIOCONCENTRATION OF TETRACHLOROBENZENE IN MARINE ALGAE

Bioconcention of tetrachlorobenzene(TeCB) in Chlorella marine, Nannochloropsis oculata,Pyramidomonas sp., Platymonas subcordiformis,and Phaeodactylum tricornutum;and toxicity of TeCB to the marinealgae were tested.Values of bioconcentration potential parameters,including uptake rate constant k1,elimination rate constant k2 and bioconcentration factor BCF, were obtaintal not only from the time course of TeCB uptake by the marine algae by using a bioconcentration model,but also from the acute toxicity test data for percent inhibition P (%) ~ exposure concentration of TeCB-time by using a combined bioconcentration and probability model. The results showed good relationship between k1(TOXIC) and k1(UPTAKE),and k2(TOXIC),k2(UPTAKE), and BCFD(TOXIC) and BCFD(UPTAKE). Especially,the values of BCFD(TOXIC) were well consisten with those of BCFD(UPTAKE).

Growth and Antimony Bioconcentration Characteristics of Wild Ramie(Boehmeria nivea)under Sb Stress in Different Valence States

[Objectives] To explore the effects of antimony(Sb) in different valence states on the growth and Sb bioconcentration and transfer of wild ramie(Boehmeria nivea). [Methods] A pot experiment was conducted to study the effects of Sb(Ⅲ) and Sb(Ⅴ) stress on plant height, biomass, leaf SPAD value, Sb contents in various organs, Sb bioconcentration and transfer factors, and other indexes. [Results] Both kinds of Sb treatments showed a trend of "first increasing and then decreasing" in plant height as Sb concentration increased. The plant heights in Sb(Ⅲ) treatments with a concentration lower than 1 000 mg/kg and Sb(Ⅴ) treatments with concentrations lower than 4 000 mg/kg were significantly higher than that of the control check(CK);and the Sb(Ⅲ) treatment of the high concentration(4 000 mg/kg) resulted in a significant decrease in plant height, while the 8 000 mg/kg Sb(Ⅴ) treatment still showed an increase in plant height, indicating that the toxicity of Sb(Ⅴ) to wild ramie was significantly lower than that of Sb(Ⅲ). The Sb(Ⅲ) treatments with a concentration lower than 2 000 mg/kg had little effect on the dry weight of the aboveground part, while the treatment with a higher concentration showed a significant decrease;and the dry weights in various concentrations of Sb(Ⅴ) treatments showed no significant differences, but they were significantly higher than the CK and corresponding concentration of Sb(Ⅲ) treatment. Both types of Sb stress could promote the increase of SPAD value in wild ramie leaves, and the performance was significantly higher than the CK. As the concentration of Sb treatment increased, the Sb content in both the aboveground and underground parts showed a significant increase;and the comparison of Sb content under corresponding concentrations of the two types of Sb treatments showed that in the aboveground part, Sb(Ⅲ) was higher than Sb(Ⅴ), while in the underground part, the opposite was true. The bioconcentration factor(BF) of Sb decreased with the increase of Sb treatment concentration overall, and the value of Sb(Ⅴ) was smaller than that of Sb(Ⅲ), but both kinds of Sb stress were significantly smaller than the CK. The transfer factor(TF) of Sb in wild ramie showed a trend of "increasing first and then decreasing" with the concentration of Sb treatment, and various treatments of Sb(Ⅲ) were higher than the CK, with significant differences, while among various treatments of Sb(Ⅴ), except treatment B3, the reduction of which was not significant, other Sb(Ⅴ) treatments showed significant decreases. Comparing the two types of Sb treatments, the BF and TF values of Sb in wild ramie under Sb(Ⅲ) treatments were higher than those under Sb(Ⅴ) treatments, and the TF reached a significant level, indicating that the Sb transport ability of wild ramie under Sb(Ⅲ) treatments was stronger. [Conclusions] This study provides a theoretical basis for the mining of wild ramie Sb restoration genes and the application of large-scale cultivation in ecological restoration.

Digital mapping of pesticides bioconcentration by integrating remote sensing techniques and plant uptake model

Although pesticides have been widely used worldwide to enhance crop yield and product quality,most pesticides are harmful to the environment and human health.Plants absorb pesticides mainly from air and soil.Therefore,the soil-plant pathway is essential for pesticide absorption.Bioconcentration factor(BCF)has extensively been applied to evaluate potential plant contamination by pesticides from soil.Hence,this study developed a simplified plant transpiration-based plant uptake model(PT-model)to estimate plant pesticides’BCF from soil based on plant transpiration.Remote sensing techniques were employed to generate spatiotemporal continuous plant transpiration via evapotranspiration.Pesticide BCF mapping was achieved by integrating PT-model with Moderate Resolution Imaging Spectroradiometer(MODIS)remotely sensed data.The results were compared with a verified model driven by relative humidity and air temperature(RA-model),which has been confirmed byfindings from previous studies.The estimated BCF was within the boundaries of the RA-model,indicating the simulation’s overall acceptability.In this study,the BCF temporal trend estimated by the proposed method agreed with the RA-model assimilating meteorology datasets,while the spatial distribution was partially inconsistent.Overall,the proposed method generates the spatiotemporal patterns of pesticide BCF with relatively consistent results supported by previous records andfindings.

Variation of Cd concentration in various rice cultivars and derivation of cadmium toxicity thresholds for paddy soil by species-sensitivity distribution

It is imperative to derive an appropriate cadmium (Cd) health risk toxicity threshold for paddy soils to ensure the Cd con-centration of rice grains meet the food safety standard. In this study, 20 rice cultivars from the main rice producing areas in China were selected, and a pot-experiment was conducted to investigate transformation of Cd in paddy soil-rice system with 0 (CK), 0.3 mg kg–1 (T1) and 0.6 mg kg–1 (T2) Cd treatments in greenhouse. The results showed that Cd concentrations of rice grains existed signiifcant difference (P<0.05) in 20 rice cultivars under the same Cd level in soil. The Cd concentrations of rice grains of the CK, T1 and T2 treatments were in the range of 0.143–0.202, 0.128–0.458 and 0.332–0.806 mg kg–1, respectively. Marked differences of the ratios of Cd concentration for soil to rice grain (BCFs) and transfer factors (TFs, root to grain and straw to grain) among the tested cultivars were observed in this study. The bioconcentration factors (BCFgrain) and TFs of the 20 rice cultivars were 0.300–1.112 and 0.342–0.817, respectively. The TFs of Cd from straw to grain ranged from 0.366 to 1.71, with signiifcant differences among these 20 rice cultivars. The bioconcentration factors (BCFgrain) and TFs among the 20 rice cultivars ranged from 0.300–1.112 and 0.342–0.817, respectively. The species-sensitivity distribu-tion (SSD) of Cd sensitivity of the rice species could be iftted wel with Burr-III (R2=0.987) based on the data of BCFs. The toxicity threshold of Cd derived from SSD for the paddy soil was 0.507 mg kg–1 in the present study.

Accumulation and bioavailability of heavy metals in a soil-wheat/maize system with long-term sewage sludge amendments

A long-term field experiment was carried out with a wheat-maize rotation system to investigate the accumulation and bioavailability of heavy metals in a calcareous soil at different rates of sewage sludge amendment. There are significant linear correlations between the contents of Hg, Zn, Cu, Pb, and Cd in soil and sewage sludge amendment rates. By increasing 1 ton of applied sludge per hectare per year in soil, the contents of Hg, Zn, Cu, Pb, and Cd in soil increased by 6.20, 619, 92.9, 49.2, and 0.500 μg kg–1, respectively. For Hg, sewage sludge could be safely applied to the soil for 18 years at an application rate of 7.5 t ha–1 before content exceeded the soil environmental quality standards in China(1 mg kg–1). The safe application period for Zn is 51 years and is even longer for other heavy metals(112 years for Cu, 224 years for Cd, and 902 years for Pb) at an application rate of 7.5 t ha–1 sewage sludge. The contents of Zn and Ni in wheat grains and Zn, Cu, and Cr in maize grains increased linearly with increasing sewage sludge amendment rates. The contents of Zn, Cr, and Ni in wheat straws and Zn, Cu, and As in maize straws were positively correlated with sewage sludge amendment rates, while the content of Cu in wheat straws and Cr in maize straws showed the opposite trend. The bioconcentration factors of the heavy metals in wheat and maize grains were found to be in the order of Zn>Cu>Cd>Hg>Cr=Ni>Pb>As. Furthermore, the bioconcentration factors of heavy metals in wheat were greater than those in maize, indicating that wheat is more sensitive than maize as an indicator plant. These results will be helpful in developing the critical loads for sewage sludge amendment in calcareous soils.

Chlorobenzenes in waterweeds from the Xijiang River (Guangdong section) of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes （CBs） in both water and waterweeds collected from 4 stations in the Xijiang River （Gangdong section） of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs （ZCBs） in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ZCBs in waterweeds ranged from 13.53×10^2μg/g to 38.27×10^2μg/g dry weight （dw）. There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs （DCBs）, whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip （bioconcentration factor） of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was： Fengkai County 〈 Yunan County 〈 Yun＇an County 〈 Gaoyao County according to the ZCBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River .

Assessing availability, phytotoxicity and bioaccumulation of lead to ryegrass and millet based on 0.1 mol/L Ca(NO_3)_2 extraction

This study was conducted to assess availability, phytotoxicity and bioaccumulation of lead （Pb） to ryegrass （Lolium perenne L.） and millet （Echinochloa crusgalli） based on the 0.1 mol/L Ca（NO3）2 extraction. Effect of soil properties on availability, phytotoxicity and bioaccumulation of Pb to the two plants was also evaluated. Five soils with pH values varying from 3.8 to 7.3, organic carbon （OC） contents from 0.7% to 2.4%, and clay contents from 11.6% to 35.6% were selected. Soils were spiked with Pb to achieve a range of concentrations： 250, 500, 1000, 3000 and 5000 mg/kg. Pb availability in the spiked soils was estimated by extracting soil with 0.1 mol/L Ca（NO3）2. The results indicate that plants yield decreased with decreasing soil pH and increased with increasing soil clay and OC content. Negative relationship between available Pb and the relative dry matter growth （RDMG） of the two plants were significantly related. Available Pb used to assess EC20 （20% effective concentration） and EC50 （50% effective concentration） of millet was 119 and 300 mg/kg, respectively. Available Pb used to assess EC20 and EC50 of ryegrass was 63 and 157 mg/kg, respectively. Bioaccumulation, expressed as bioconcentration factors of Pb, was inversely related to soil pH, soil OC and clay content. Strong relationships were found between available lead and uptake by the two plants （P was 0.92 and 0.95 respectively）. In general, 0.1 mol/L Ca（NO3）2 available Pb may be used to assess the availability, phytotoxicity and bioaccumulation of lead to the two plants tested.

Mercury Distribution and Accumulation in Typical Wetland Ecosystems of Sanjiang Plain,Northeast China

Total mercury in soil,water,plant,insects,fishes and bird feathers were determined to study mercury distribution and accumulation in typical wetland ecosystems in the Sanjiang Plain,Northeast China.Results show that total mercury concentrations in soils of Deyeuxia angustifolia wetland and Carex lascarpa wetland are 0.046 mg/kg and 0.063 mg/kg,respectively.Total mercury concentration in water bodies is 0.053 μg/L on average.Of four plants studied,total mercury in moss is the highest with the mean of 0.132 mg/kg.Of 10 terrestrial insect species studied,total mercury in centipede(Scolopendra spp.) is the highest with the mean of 0.515 mg/kg while total mercury in grasshopper(Oxya spp.) bodies is the lowest.Total mercury concentrations in the herbivorous,omnivorous and predatory insects are 10.18 ng/g,16.47 ng/g and 213.35 ng/g on average,respectively.Total mercury concentrations of the adult feather(549.88 ± 63.04 ng/g),nestling feather(55.15 ± 23.53 ng/g),and eggshell(22.05 ± 5.96 ng/g) of the Grey heron(Ardea cinerea) are higher than those of the Great egret(Egretta alba)(adult feather:446.57 ± 90.89 ng/g;nestling feather:32.99 ± 17.15 ng/g;eggshell:21.02 ± 3.17 ng/g) in the wetlands of the Sanjiang Plain.The bioconcentration factors decrease in the order of piscivorous fish muscle > omnivorous fish muscle > herbivorous fish > insect.

Effects of soil properties on accumulation characteristics of copper,manganese, zinc, and cadmium in Chinese turnip

Clarifying the mechanisms of heavy metal(HM)accumulation and translocation from soil-root-leaf is crucial to coping with soil HM pollution.In this study,we analysed copper(Cu),manganese(Mn),zinc(Zn)and cadmium(Cd)accumulation characteristics in Chinese turnips and the effect of soil physicochemical properties on both HM accumulation and translocation.Our results indicate that Chinese turnips absorb and translocate Mn,Zn,and Cd at much higher levels than they do Cu.When we measured bioconcentration factors in Chinese turnips for different HMs in the same soil,we found Chinese turnip capacities for HM accumulation decrease from Zn>Mn>Cd>Cu.In addition,the translocation factor for these HMs decreases from Mn>Cd>Zn>Cu.Correlation analysis indicates that soil p H and various soil components are either negatively or positively correlated with Mn,Zn,and Cd accumulation;also,soil properties are correlated with Mn translocation from root to leaf.These findings may help evaluate HM accumulation and translocation mechanisms as well as artificially regulate HM uptake levels from soils to turnips.

Preliminary assessment of revegetation potential through ryegrass growing on bauxite residue

Bauxite residue(BR),a by-product of the industrial production of alumina,has raised environmental concerns in the last decades,due to the presence of high amounts of alkali and various heavy metal ions.Limited studies on the application of abandoned BR with massive consumption have been reported.In this study,the possibility of the revegetation using ryegrass growing on BR was discussed mainly through the growth indications and transfer of heavy metal ions in BR and plants.In the pot trails,ryegrass was seeded on BR,de-alkali BR,with(DBRO)or without(DBR)organic fertilizer,respectively.The results indicated that the remediation of bauxite residue can be achieved through de-alkali with acid neutralization.Elemental analysis indicated that the elements,except for Fe,Mn and Pb,were stable in plant roots,and ryegrass could hardly absorb Cd.But,some heavy metals such as Cu enriched in plants,which should be noted in revegetation on bauxite residue.

The level and bioaccumulation of Cd, Cu, Cr and Zn in benthopelagic species from the Bering Sea

The Bering Sea is an area of high biological productivity, with large populations of sea-birds, demersal and pelagic fishes, so it seemed desirable to assess the bioaccumulation of trace metals in the marine organisms from this area. However, few data on trace metal concentrations are available for the benthopelagic organisms from the Bering Sea till now. Ten specimens of benthos （including 120 biological samples） were collected in the western Bering Sea in August 2008 during the 3rd Chinese National Arctic Research Expeditions, and the concentration of Cd, Cu, Cr and Zn determined using atomic absorption spectrometry. Zn, Cr and Cd concentrations in muscle tissues of the crab species were much higher than those from fish and cephalopod species, and the highest concentration of Cu was observed in the muscle tissues of Cylichna nucleoli. The results showed a similar hierarchy for Zn, Cr, Cd and Cu concentrations among different tissues as follows： hepatopancreas〉muscle tissue〉gonad. Bioconcentration factors indicated that benthic organisms had high accumulation abilities for Zn and Cu.

Zinc and copper bioaccumulation in fi sh from Laizhou Bay, the Bohai Sea

Abstract Zinc （Zn） and copper （Cu） concentrations were determined in the tissues （muscle, stomach, liver, gills, skin, and gonads） of five commercial fish species （mullet Liza haematocheilus, flathead Platycephalus indicus, mackerel Scomberomorus niphonius, silver pomfret Pampus argenteus, and sea bass Lateolabrax japonicus） from Laizhou Bay in the Bohai Sea. Metal bioaccumulation was highest in the metabolically active tissues of the gonads and liver. Bioconcentration factors for Zn were higher in all tissues （gonads 44.35, stomach 7.73, gills 7.72, liver 5.61, skin 4.88, and muscle 1.63） than the corresponding values for Cu （gonads 3.50, stomach 3.00, gills 1.60, liver 5.43, skin 1.50, and muscle 0.93）. Mackerel tissues accumulated metal to higher concentrations than did other fish species, but bioaccumulation levels were not significantly correlated with the trophic levels of the fish. Zn and Cu concentrations in the tissues were generally negatively correlated with fish length, except for a few tissues of sea bass. Risk assessment based on national and international permissible limits and provisional tolerances for weekly intake of Zn and Cu revealed that the concentrations of these two metals in muscle were relatively low and would not pose hazards to human health.

Mineral Constituents in Common Chanterelles and Soils Collected from a High Mountain and Lowland Sites in Poland

This paper reported the results of the determination of Ag, A1, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr and Zn in Common Chanterelles （Cantharellus cibarius） Fr. and surface soil layer （o-io cm） underneath the fruiting bodies. Mushrooms and soils were collected from a lowland site in the Hel Peninsula （Baltic Sea coast） and a high mountain site in the Tatra Mountains. The trace elements were determined using validated method and inductively coupled plasma - atomic emission spectroscopy （ICP-AES）. Common Chanterelles that emerged at sites poor in mineral nutrients podzols of the Hel Peninsula forests efficiently bioeoncentrated several essential trace elements （K, P, Co, Cu, Mn, Na, Zn）, while the abundance of those elements in carpophores was around half less compared to specimens from Zakopane region and which emerged in soils much richer in minerals. Common Chanterelles collected at two spatially distant background areas in Poland were only weakly contaminated with metals such as Ag, Cd, Hg and Pb. The maximum tolerable Cd and Pb contents of certain cultivated mushrooms are regulated in the European Union by law and these hazardous metals in C. cibarius were far below tolerance limits set.