Uptake and translocation of organophosphates and other emerging contaminants in food and forage crops

Emerging contaminants in wastewater and sewage sludge spread on agricultural soil can be transferred to the human food web directly by uptake into food crops or indirectly following uptake into forage crops. This study determined uptake and translocation of the organophosphates tris(1-chloro-2-propyl) phosphate (TCPP) (log K _ow 2.59), triethyl-chloro-phosphate (TCEP) (log K _ow 1.44), tributyl phosphate (TBP) (log K _ow 4.0), the insect repellent N,N-diethyl toluamide (DEET) (log K _ow 2.18) and the plasticiser N-butyl benzenesulfonamide (NBBS) (log K _ow 2.31) in barley, wheat, oilseed rape, meadow fescue and four cultivars of carrot. All species were grown in pots of agricultural soil, freshly amended contaminants in the range of 0.6–1.0 mg/kg dry weight, in the greenhouse. The bioconcentration factors for root (RCF), leaf (LCF) and seed (SCF) were calculated as plant concentration in root, leaf or seed over measured initial soil concentration, both in dry weight. The chlorinated flame retardants (TCEP and TCPP) displayed the highest bioconcentration factors for leaf and seed but did not show the same pattern for all crop species tested. For TCEP, which has been phased out due to toxicity but is still found in sewage sludge and wastewater, LCF was 3.9 in meadow fescue and 42.3 in carrot. For TCPP, which has replaced TCEP in many products and also occurs in higher residual levels in sewage sludge and wastewater, LCF was high for meadow fescue and carrot (25.9 and 17.5, respectively). For the four cultivars of carrot tested, the RCF range for TCPP and TCEP was 10–20 and 1.7–4.6, respectively. TCPP was detected in all three types of seeds tested (SCF, 0.015–0.110). Despite that DEET and NBBS have log K _ow in same range as TCPP and TCEP, generally lower bioconcentration factors were measured. Based on the high translocation of TCPP and TCEP to leaves, especially TCPP, into meadow fescue (a forage crop for livestock animals), ongoing risk assessments should be conducted to investigate the potential effects of these compounds in the food web.     

Antibiotic uptake by plants from manure-amended soils

Antibiotics are extensively given to livestock to promote growth and reduce diseases. Therefore, animal manure often contains antibiotics. Once manure is applied to agricultural land to improve soil productivity, crops would be exposed to antibiotics which may persist in soils from a few to several hundred days. The objective of this study was to evaluate the uptake of gentamicin and streptomycin by carrot (Daucus carota), lettuce (Lactuca sativa) and radish (Rhaphanus sativus) from manure-amended soil. The treatments were 0, 0.5 and 1 mg of antibiotic kg^?1 of soil. Two pot experiments were carried out in the greenhouse. The first was conducted on the three crops and the second exclusively on radish. In radish, the increase in the concentrations of gentamicin was significant between the 0 and both of 0.5 and 1.0 mg kg^?1 treatments, but not significant between the 0.5 and 1.0 mg kg^?1. The average values were 35.5, 60.0 and 57.4 μg kg^?1 for the 0, 0.5 and 1 mg kg^?1 rates, respectively. However, the increase in streptomycin concentration in radish was not significant between the three treatments, and the average values were, 12.1, 15.2 and 17.4 μg kg^?1 for the 0, 0.5 and 1 mg kg^?1 rates, respectively. In carrot roots and lettuce leaves no significant increase in the concentrations of gentamicin or streptomycin was observed between the treatments. The three crops absorbed relatively higher amounts of gentamicin (small molecule) than streptomycin (large molecule). Generally the levels of antibiotics in plant tissue increased with increasing the antibiotic concentration in the manure (1 mg kg^?1 > 0.5 mg kg^?1).     

The effects of the nitrofuran furaltadone on Ulva lactuca

The use of pharmaceuticals in the food production industry as prophylatic and therapeutic agents is necessary to promote animal health, but may entail significant consequences to natural ecosystems, especially in the cases of overdosing and use of banned pharmaceuticals. The vast effects that antibiotics released into the environment have on non-target organisms are already under the scope of researchers but little attention has been given to primary producers such as macroalgae. The present study assessed furaltadone’s, an antibacterial agent illegally used for veterinary purposes, uptake capacity by Ulva lactuca and its effect in the growth of this cosmopolitan macroalgae. Differences in macroalgal growth were shown when submitted to prophylactic and therapeutic concentrations of furaltadone in the water (16 and 32 μg mL⁻¹, respectively). The therapeutic concentration caused higher growth impairment than the prophylactic treatment did, with 87.5% and 58% reductions respectively. Furthermore, together with data collected from the accumulation assays, with values of internal concentrations as high as 18.84 μg g⁻¹ WW, suggest that the macroalgae U. lactuca should be included in field surveys as a biomonitor for the detection of nitrofurans.     

Effects of the aquatic contaminant human pharmaceuticals and their mixtures on the proliferation and migratory responses of the bioindicator freshwater ciliate Tetrahymena

An increasing attention is paid to the potential harmful effects of aquatic contaminant pharmaceuticals exerted on both biosystems and humans. In the present work the effects of 14 pharmaceuticals including NSAIDs, antibiotics, β-blockers and a frequently used X-ray contrast media on the proliferation and migratory behavior of the freshwater ciliate Tetrahymena pyriformis was investigated. Moreover, the mixture toxicity of four selected pharmaceuticals (diclofenac, ibuprofen, metoprolol and propranolol) was evaluated in binary mixtures using full factorial experimental design. Our results showed that the sensitivity of Tetrahymena to NSAIDs and β-blockers (EC₅₀ ranged from 4.8 mg L⁻¹ to 308.1 mg L⁻¹) was comparable to that of algal or Daphnia bioassays. Based on these elevated EC₅₀ values acute toxic effects of these pharmaceuticals to T. pyriformis are unlikely. Antibiotics and the contrast agent sodium-diatrizoate had no proliferation inhibiting effect. Chemotactic response of Tetrahymena was more sensible than proliferation as significant chemorepellent action was observed in the environmentally realistic concentration range for acetylsalicylic acid, diclofenac, fenoprofen, paracetamol, metoprolol, propranolol, timolol and trimethoprim (Chemotaxis Index ranged from 63% to 88%).Mixture toxicity experiments resulted in a complex, concentration dependent interaction type pattern with antagonism being the predominant interaction type (59%) followed by additivity (37%) and synergism (4%). Hence the concept of concentration addition validated for NSAIDs in other organisms cannot be adopted for this ciliate.In summary authors suggest Tetrahymena as a sensible model of testing aquatic contaminants as well as underline the significance using more specific endpoints to understand the complex mechanisms investigated.     

Growth and photosynthetic responses to copper in wild grapevine

The present study evaluates the tolerance and accumulation potential of Vitis vinifera ssp. sylvestris under moderate and high external Cu levels. A greenhouse experiment was conducted in order to investigate the effects of a range of external Cu concentrations (0–23 mmol L⁻¹) on growth and photosynthetic performance by measuring gas exchange, chlorophyll fluorescence parameters and photosynthetic pigments. We also measured the total copper, nitrogen, phosphorus, sulphur, calcium, magnesium, iron, potassium and sodium concentrations in the plant tissues. All the experimental plants survived even with external Cu concentrations as high as 23 mmol L⁻¹ (1500 mg Cu L⁻¹), although the excess of metal resulted in a biomass reduction of 35%. The effects of Cu on growth were linked to a reduction in net photosynthesis, which may be related to the effect of the high concentration of the metal on photosynthetic electron transport. V. vinifera ssp. sylvestris survived with leaf Cu concentrations as high as 80 mg kg⁻¹ DW and growth parameters were unaffected by leaf tissue concentrations of 35 mg Cu kg⁻¹ DW. The results of our study indicate that plants of V. vinifera ssp. sylvestris from the studied population are more tolerant to Cu than the commercial varieties of grapevine that have been studied in the literature, and could constitute a basis for the genetic improvement of Cu tolerance in grapevine.     

Microbial degradation of pharmaceuticals in estuarine and coastal seawater

Microbial degradation rates were measured for 19 pharmaceuticals in estuarine and coastal surface water samples. Antipyrine, carbamazepine, cotinine, sulfamethoxazole, and trimethoprim were the most refractory (half-lives, t_1/2 = 35 to >100 days), making them excellent candidates for wastewater tracers. Nicotine, acetaminophen, and fluoxetine were labile across all treatments (t_1/2 = 0.68-11 days). Caffeine, diltiazem, and nifedipine were also and relatively labile in all but one of the treatments (t_1/2 = 3.5-13 days). Microbial degradation of caffeine was further confirmed by production ¹⁴CO₂. The fastest decay of non-refractory compounds was always observed in more sewage-affected Jamaica Bay waters. Degradation rates for the majority of these pharmaceuticals are much slower than reported rates for small biomolecules, such as glucose and amino acids. Batch sorption experiments indicate that removal of these soluble pharmaceuticals from the water column to sediments is a relatively insignificant removal process in these receiving waters.     

Determination of veterinary pharmaceuticals in poultry litter and soil by methanol extraction and liquid chromatography-tandem mass spectrometry

Pharmaceuticals are emerging contaminants with potential risks to the environment and human health. A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed for determination of the antimicrobials virginiamycin, monensin, salinomycin, narasin and nicarbazin in poultry litter and soil. This method involves methanol extraction and clean-up of extracts through glass microfibre filters, introduction of the extracts and separation of compounds on a Zorbax Eclipse XDB C8 column, and compound detection in a Quattro Micro Micromass spectrometer. For litter samples, Method Detection Limits ranged from 0.1–0.6 μg Kg^{? 1}, while Limits of Quantitation (LOQs) were 2, 1, 0.4, 1 and 2 μg Kg^{? 1} for virginiamycin, monensin, salinomycin, narasin and nicarbazin, respectively. For soil samples calculated LOQs were 2, 3, 1, 1, and 1 μg Kg^{? 1} for virginiamycin, monensin, salinomycin, narasin and nicarbazin, respectively. Application of the LC-MS-MS method for detection of veterinary pharmaceuticals in litter collected from commercial poultry farms showed that compounds were present at concentrations ranging from 10–11,000 μg Kg^{? 1}.     

Effect of chronic exposure to acetaminophen and lincomycin on Japanese medaka (Oryzias latipes) and freshwater cladocerans Daphnia magna and Moina macrocopa, and potential mechanisms of endocrine disruption

Chronic toxicity of acetaminophen and lincomycin were evaluated using freshwater organisms including two crustaceans (Daphnia magna and Moina macrocopa) and a fish (Oryzias latipes). H295R, a human adrenal cell was also used to understand the effects on steroidogenesis. In 21 d D. magna exposure, survival NOEC was found at 5.72 mg L⁻¹ and no reproduction related effects were noted at this level of exposure to acetaminophen, while 21 d survival or growth effects were not observed even at the highest exposure levels (153 mg L⁻¹) for lincomycin. In the chronic fish toxicity test, significant reduction in juvenile survival was observed at 30 d post-hatch (dph) at 95 mg L⁻¹ of acetaminophen, and 0.42 mg L⁻¹ of lincomycin. After the exposure to both pharmaceuticals, vitellogenin levels tended to increase in male fish at 90 dph. In the eggs which were prenatally exposed to 9.5 mg L⁻¹ of acetaminophen, reduced hatchability was observed. The results of H295R cell assay showed that both pharmaceuticals could alter steroidogenic pathway and increase estrogenicity. Endocrine disruption potentials and their ecological implication may deserve further studies. Our observations suggest however that ecological risks of both pharmaceuticals are negligible at the concentrations currently found in the environment.     

Can arbuscular mycorrhizal fungi improve grain yield, As uptake and tolerance of rice grown under aerobic conditions?

The effects of arbuscular mycorrhizal fungi (AMF) - Glomus intraradices and G. geosporum on arsenic (As) and phosphorus (P) uptake by lowland (Guangyinzhan) and upland rice (Handao 502) were investigated in soil, spiked with and without 60 mg As kg⁻¹. In As-contaminated soil, Guangyinzhan inoculated with G. intraradices or Handao 502 inoculated with G. geosporum enhanced As tolerance, grain P content, grain yield. However, Guangyinzhan inoculated with G. geosporum or Handao 502 inoculated with G. intraradices decreased grain P content, grain yield and the molar ratio of grain P/As content, and increased the As concentration and the ratio of grain/straw As concentration. These results show that rice/AMF combinations had significant (p < 0.05) effects on grain As concentration, grain yield and grain P uptake. The variation in the transfer and uptake of As and P reflected strong functional diversity in AM (arbuscular mycorrhizal) symbioses.     

Pharmaceuticals in settleable particulate material in urban and non-urban waters

Wastewater treatment plants (WWTP) are important sources of settleable particulate material (SPM), heading to sediments with natural suspended solids. To date, there is little information about the fate of pharmaceuticals in sediment systems. In this study, the objective was to determine if pharmaceuticals are detected in SPM at locations near WWTPs or even in rural areas, thus being susceptible for sedimentation.SPM samples were collected from 10 sites in Finland, grouped as reference, rural and wastewater effluent sites. SPM collectors were placed about 35 cm above bottom for about 2 months during summer. After extraction, a set of 17 pharmaceuticals was analyzed.Several pharmaceuticals were detected in SPM accumulated at sites next to WWTPs. The concentration of citalopram was notably high (300-1350 ng g⁻¹ dw). Also bisoprolol and ciprofloxacin were detected at high concentrations (6-325 and 9-390 ng g⁻¹ dw, respectively). In contrast, none of the pharmaceuticals were detected from reference sites and only two were found from a single rural site.There is no previous information about the presence of pharmaceuticals in SPM. The results showed that pharmaceuticals are sorbed to particles in WWTP and nearby, eventually ending up in sediments. These results also indicate that pharmaceuticals are not markedly contaminating sediments of rural areas in Finland.     

Bioconcentration of ibuprofen in fathead minnow (Pimephales promelas) and channel catfish (Ictalurus punctatus)

Pharmaceutical products and their metabolites are being widely detected in aquatic environments and there is a growing interest in assessing potential risks of these substances to fish and other non-target species. Ibuprofen is one of the most commonly used analgesic drugs and no peer-reviewed laboratory studies have evaluated the tissue specific bioconcentration of ibuprofen in fish. In the current study, fathead minnow (Pimephales promelas) were exposed to 250 μg L⁻¹ ibuprofen for 28 d followed by a 14 d depuration phase. In a minimized bioconcentration test design, channel catfish (Ictalurus punctatus) were exposed to 250 μg L⁻¹ for a week and allowed to depurate for 7 d. Tissues were collected during uptake and depuration phases of each test and the corresponding proportional and kinetic bioconcentration factors (BCFs) were estimated. The results indicated that the BCF levels were very low (0.08-1.4) implying the lack of bioconcentration potential for ibuprofen in the two species. The highest accumulation of ibuprofen was observed in the catfish plasma as opposed to individual tissues. The minimized test design yielded similar bioconcentration results as those of the standard test and has potential for its use in screening approaches for pharmaceuticals and other classes of chemicals.     

Assisted phytoremediation of mixed metal(loid)-polluted pyrite waste: effects of foliar and substrate IBA application on fodder radish

Exogenous application of plant-growth promoting substances may potentially improve phytoremediation of metal-polluted substrates by increasing shoot and root growth. In a pot-based study, fodder radish (Raphanus sativus L. var. oleiformis Pers.) was grown in As-Zn-Cu-Co-Pb-contaminated pyrite waste, and treated with indolebutyric acid (IBA) either by foliar spraying (10 mg L⁻¹), or by direct application of IBA to the substrate (0.1 and 1 mg kg⁻¹) in association, or not, with foliar spraying. With the exception of foliar spraying, IBA reduced above-ground biomass, whilst direct application of IBA to the substrate surface reduced root biomass (−59%). Trace element concentrations were generally increased, but removals (mg per plant) greatly reduced with IBA application, together with greater metal leaching from the substrate. It is concluded that, in our case, IBA had a negative effect on plant growth and phytoextraction of trace elements, possibly due to unsuitable root indoleacetic acid concentration following soil IBA application, the direct chelating effect of IBA and the low microbial activity in the pyrite waste affecting its breakdown.     

Uptake of polychlorinated biphenyls and organochlorine pesticides from soil and air into radishes (Raphanus sativus)

Uptake of organochlorine pesticides and polychlorinated biphenyls from soil and air into radishes was measured at a heavily contaminated field site. The highest contaminant concentrations were found for DDT and its metabolites, and for β-hexachlorocyclohexane. Bioconcentration factor (BCF, defined as a ratio between the contaminant concentration in the plant tissue and concentration in soil) was determined for roots, edible bulbs and shoots. Root BCF values were constant and not correlated to log K_OW. A negative correlation between BCF and log K_OW was found for edible bulbs. Shoot BCF values were rather constant and varied between 0.01 and 0.22. Resuspended soil particles may facilitate the transport of chemicals from soil to shoots. Elevated POP concentrations found in shoots of radishes grown in the control plot support the hypothesis that the uptake from air was more significant for shoots than the one from soil. The uptake of POPs from air was within the range of theoretical values predicted from log K_OA.     

The effects of dissolved organic matter and pH on sampling rates for polar organic chemical integrative samplers (POCIS)

The effect of solution pH and levels of dissolved organic matter (DOM) on the sampling rates for model pharmaceuticals and personal care products (PPCPs) and endocrine disrupting substance (EDS) by polar organic chemical integrative samplers (POCIS) was investigated in laboratory experiments. A commercially available POCIS configuration containing neutral Oasis HLB (hydrophilic-lipophilic balance) resin (i.e. pharmaceutical POCIS) and two POCIS configurations prepared in-house containing MAX and MCX anion and cation exchange resins, respectively were tested for uptake of 21 model PPCPs and EDS, including acidic, phenolic, basic and neutral compounds. Laboratory experiments were conducted with dechlorinated tap water over a pH range of 3, 7 and 9. The effects of DOM were studied using natural water from an oligotrophic lake in Ontario, Canada (i.e. Plastic Lake) spiked with different amounts of DOM (the concentration of dissolved organic carbon ranged from 3 to 5 mg L⁻¹ in uptake experiments). In experiments with the commercial (HLB) POCIS, the MCX-POCIS and the MAX-POCIS, the sampling rates generally increased with pH for basic compounds and declined with pH for acidic compounds. However, the sampling rates were relatively constant across the pH range for phenols with high pKa values (i.e. bisphenol A, estrone, estradiol, triclosan) and for the neutral pharmaceutical, carbamazepine. Thus, uptake was greatest when the amount of the neutral species in solution was maximized relative to the ionized species. Although the solution pH affected the uptake of some model ionic compounds, the effect was by less than a factor of 3. There was no significant effect of DOM on sampling rates from Plastic Lake. However, uptake rates in different aqueous matrixes declined in the order of deionized water > Plastic Lake water > dechlorinated tap water, so other parameters must affect uptake into POCIS, although this influence will be minor. MAX-POCIS and MCX-POCIS showed little advantage over the commercial POCIS configuration for monitoring in natural waters.     

Bromination of selected pharmaceuticals in water matrices

The bromination of five selected pharmaceuticals (metoprolol, naproxen, amoxicillin, phenacetin, and hydrochlorothiazide) was studied with these compounds individually dissolved in ultra-pure water. The apparent rate constants for the bromination reaction were determined as a function of the pH, obtaining the sequence amoxicillin > naproxen ? hydrochlorothiazide ≈ phenacetin ≈ metoprolol. A kinetic mechanism specifying the dissociation reactions and the species formed for each compound according to its pK_a value and the pH allowed the intrinsic rate constants to be determined for each elementary reaction. There was fairly good agreement between the experimental and calculated values of the apparent rate constants, confirming the goodness of the proposed reaction mechanism.In a second stage, the bromination of the selected pharmaceuticals simultaneously dissolved in three water matrices (a groundwater, a surface water from a public reservoir, and a secondary effluent from a WWTP) was investigated. The pharmaceutical elimination trend agreed with the previously determined rate constants. The influence of the main operating conditions (pH, initial bromine dose, and characteristics of the water matrix) on the degradation of the pharmaceuticals was established. An elimination concentration profile for each pharmaceutical in the water matrices was proposed based on the use of the previously evaluated apparent rate constants, and the theoretical results agreed satisfactorily with experiment. Finally, chlorination experiments performed in the presence of bromide showed that low bromide concentrations slightly accelerate the oxidation of the selected pharmaceuticals during chlorine disinfection.     

不同来源的海州香薷和野胡萝卜的铜抗性及铜积累差异

以来自矿区(铜绿山和赤马山铜矿)和非矿区(红安、武汉严西湖)的海州香薷和野胡萝卜种群为对象,通过土培实验,研究了2种植物的铜抗性及铜吸收积累差异.结果显示,来自矿区的海州香薷和野胡萝卜种群的铜抗性都明显高于非矿区种群,但2种植物种群的铜吸收积累特征明显不同:海州香薷植物吸收的Cu主要集中在根中,但矿区种群吸收积累的铜量明显低于非矿区种群;而野胡萝卜吸收的Cu主要集中在地上部分(地上部分的Cu富集量是根的1.5倍),但积累的铜量在矿区和非矿区种群间没有明显的差异.因此,来自矿区的海州香薷可能进化为铜避性对策,而野胡萝卜的铜抗性与其吸收积累的总量没有明显的关系,但有很好的向地上运输能力.     

Diagnosis of dissolved organic matter removal by GAC treatment in biologically treated papermill effluents using advanced organic characterisation techniques

Granular activated carbon (GAC) exhaustion rates on pulp and paper effluent from South East Australia were found to be a factor of three higher (3.62 cf. 1.47 kg m⁻³) on Kraft mills compared to mills using Thermomechanical pulping supplemented by Recycled Fibre (TMP/RCF). Biological waste treatment at both mills resulted in a final effluent COD of 240 mg L⁻¹. The dissolved organic carbon (DOC) was only 1.2 times higher in the Kraft effluent (70 vs. 58 mg L⁻¹), however, GAC treatment of Kraft and TMP/RCF effluent was largely different on the DOC persisted after biological treatment. The molecular mass (636 vs. 534 g mol⁻¹) and aromaticity (5.35 vs. 4.67 L mg⁻¹ m⁻¹) of humic substances (HS) were slightly higher in the Kraft effluent. The HS aromaticity was decreased by a factor of 1.0 L mg⁻¹ m⁻¹ in both Kraft and TMP/RCF effluent. The molecular mass of the Kraft effluent increased by 50 g mol⁻¹ while the molecular mass of the TMP/RCF effluent was essentially unchanged after GAC treatment; the DOC removal efficiency of the GAC on Kraft effluent was biased towards the low molecular weight humic compounds. The rapid adsorption of this fraction, coupled with the slightly higher aromaticity of the humic components resulted in early breakthrough on the Kraft effluent. Fluorescence excitation-emission matrix analysis of the each GAC treated effluent indicated that the refractory components were higher molecular weight humics on the Kraft effluent and protein-like compounds on the TMP/RCF effluent. Although the GAC exhaustion rates are too high for an effective DOC removal option for biologically treated pulp and paper mill effluents, the study indicates that advanced organic characterisation techniques can be used to diagnose GAC performance on complex effluents with comparable bulk DOC and COD loads.     

Effect of external iron and arsenic species on chelant-enhanced iron bioavailability and arsenic uptake in rice (Oryza sativa L.)

This study was conducted to investigate the effect of external iron status and arsenic species on chelant-enhanced iron bioavailability and arsenic uptake. Rice seedlings (Oryza sativa L.) were used as model plant, and were grown in artificially contaminated sandy soils irrigated with Murashige and Skoog (MS) culture solution. Arsenate uptake in roots and shoots of rice seedlings were affected significantly (p > 0.05) while dimethylarsinic acid (DMAA) was not by the additional iron and chelating ligand treatments. Regardless of iron concentrations in the soil solution, HIDS increased arsenic uptake for roots more than EDTA and EDDS. Chelating ligands and arsenic species also influenced iron uptake in rice roots. Irrespective of arsenic species, HIDS was found to be more effective in the increase of iron bioavailability and uptake in rice roots compared to other chelants. There was a significant positive correlation (r = 0.78, p < 0.05) between arsenate and iron concentrations in the roots of rice seedlings grown with or without additional iron indicating that arsenate inhibit iron uptake. In contrast, there was no correlation between iron and DMAA uptake in roots. Poor correlation between iron and arsenic in shoots indicated that iron uptake in shoots was neither affected by additional iron nor by arsenic species. Compared to the control, chelating ligands increased iron uptake in shoots of rice seedlings significantly (p < 0.05). Regardless of additional iron and arsenic species, iron uptake in rice shoots did not differed among EDTA, EDDS, and HIDS treatments.     

不同纳米修复剂对污染土壤中胡萝卜吸收、转运Cd的影响

通过盆栽实验研究不同纳米修复剂(羟基磷灰石HAP、赤泥RM、Fe3O4、胡敏酸-Fe3O4)对2种不同污染土壤Cd吸收、转运的影响。结果表明,上述纳米修复剂均可显著增加胡萝卜植株生物量,显著提高植株Cd胁迫的耐受指数;不同土壤施用不同纳米修复剂均显著降低胡萝卜植株Cd的含量,并且随着修复剂施加浓度的增加而显著降低;与对照相比,植株茎叶Cd含量最大降低达78.8%,根中Cd的含量最大降低67.8%;添加不同修复剂能不同程度地降低了土壤中Cd的转运系数和富集系数,这可能与施用不同纳米修复剂促进了土壤中非残留态Cd向残留态Cd的转化有关,总体而言,不同纳米型修复剂对降低Cd的有效性顺序为:RM～HAP>胡敏酸-Fe3O4>Fe3O4。     

Trophic transfer of pyrene metabolites and nonextractable fraction from Oligochaete (Lumbriculus variegatus) to juvenile brown trout (Salmo trutta)

Cell lines of Etroplus suratensis established in our laboratory were evaluated for their potential use as screening tools for the ecotoxicological assessment of tannery effluent. The cytotoxic effect of tannery effluent in three cell lines derived from eye, kidney and gill tissue of E. suratensis was assessed using multiple endpoints such as Neutral Red (NR) assay, Coomassie Blue (CB) protein assay and Alamar Blue (AB) assay. Acute toxicity tests on fish were conducted by exposing E. suratensis for 96 h to tannery effluent under static conditions. The toxic effect of tannery effluent on the survival of fish was found to be concentration and time dependent. The tannery effluent at the concentration of 15% caused 100% mortality at 96 h whereas the lower concentration (0.5%) caused 13.33% mortality. The cytotoxicity of tannery effluent was found to be similar in the three cell lines tested, independent of the toxic endpoints employed. EC₅₀ values, the effective concentration of tannery effluent resulting in 50% inhibition of cytotoxicity parameters after 48 h exposure to tannery effluent were calculated for eye, kidney and gill cell lines using NR uptake, AB and cell protein assays. Statistical analysis revealed good correlation with r² = 0.95-0.99 for all combinations between endpoints employed. Linear correlations between each in vitro EC₅₀ and the in vivo LC₅₀ data, were highly significant p < 0.001 with r² = 0.977, 0.968 and 0.906 for AB₅₀, NR₅₀, and CB₅₀, respectively.