Removal of Chromium from Soils Cultivated with Maize (<Emphasis Type="Italic">Zea Mays</Emphasis>) After the Addition of Natural Minerals as Soil Amendments

The efficiency of natural minerals, i.e. zeolite, bentonite and goethite, regarding the retention of chromium, from maize was examined. Specifically, 1.0 kg of soil, 1.0 g of soil amendment and either 50 mg L^?1 Cr(III) or 1 mg L^?1 Cr(VI) were added in plant pots. Then, seeds of maize were cultivated. Each treatment was repeated three times. The statistical results of the experiments were analyzed by LSD test. Cr(III) addition in soil has shown that zeolite was the only amendment that increased the dry weight. Zeolite and bentonite reduced significantly the total chromium in plants after the addition of 50 mg L^?1 Cr(III). The addition of Cr(VI) in soil has shown that bentonite was the only amendment that increased the dry weight of biomass and the plants’ height. All soil amendments reduced to zero the total chromium concentration measured to plants after the addition of 1 mg L^?1 Cr(VI).     

Toxicity and Genotoxicity of Three Antimicrobials Commonly Used in Veterinary Medicine

The toxicity of chlortetracycline (CTC), oxytetracycline (OTC) and enrofloxacin (ENF) was tested on two green algal species: the international standard Pseudokirchneriella subcapitata and the native Argentine species Ankistrodesmus fusiformis. All three antibiotics inhibited the algal growth. The most sensitive species was P. subcapitata, for which the EC₅₀ for CTC, OTC and ENF were 1.19?±?0.53, 0.92?±?0.30 and 5.18?±?3.80 mg L^?1, respectively. The EC₅₀ for A. fusiformis, were 3.23?±?0.53, 7.15?±?2.69 and 10.6?±?1.28 mg L^?1, respectively. The genotoxicity of these veterinary antibiotics was also assessed using chromosome aberration (CA) and micronuclei (MN) induction in Allium cepa roots. Three concentrations were tested (0.1, 1 and 10 mg L^?1). Only ENF at 1 and 10 mg L^?1 showed any significant MN induction. These data revealed that CTC, OTC and ENF could cause toxicity on green algae, whereas ENF could cause genotoxicity on A. cepa plants.     

Haemocyte Apoptosis of the Tiger Shrimp Penaeus monodon Exposed to Cadmium

This study investigated the effect of ambient Cadmium (Cd) on haemocyte apoptosis of the shrimp, Penaeus monodon. Cellular response was determined in Cd-exposed (0, 0.05, 0.5 and 5 mg L^?1) shrimp. Results showed that 0.05 mg L^?1 Cd²⁺ had no significant effect on the haemocyte parameters during the 48 h exposure. Cadmium at doses of 0.5 and 5 mg L^?1 depressed the total haemocyte count (THC), and increased reactive oxygen species (ROS) production and apoptosis ratio in haemocytes. Esterase activity increased in shrimp exposed to 0.5 mg L^?1 Cd²⁺ for 6 h, and decreased to the initial level later. Depressed esterase activity could be observed in shrimp after 24 and 48 h exposure to 5 mg L^?1 Cd²⁺. These results demonstrated that Cd²⁺ modified esterase activity and induced ROS generation, which led to haemocyte apoptosis and THC reduction. Oxidative stress is one of the induction mechanisms for Cd-caused apoptosis of shrimp haemocytes.     

Acute Toxicity of Nitrite to Various Life Stages of the Amazon River Prawn,Macrobrachium amazonicum,Heller, 1862

This study determined the effects of nitrite on different life stages of the Amazon river prawn Macrobrachium amazonicum. Prawns of each life stage (postlarvae, juveniles and adults) were stocked in 24 experimental units (n?=?10 prawns), under a complete randomized design. Individuals were exposed to nitrite (0, 1, 2, 4, 8 and 16 mg L^?1). The median lethal concentration after 96 h (96 h LC₅₀) was calculated through the Weibull I. The mortality results showed that M. amazonicum is slightly less tolerant to nitrite than other species of Macrobrachium. The 96 h LC₅₀ for postlarvae, juveniles and adults of M. amazonicum were of 1.49, 2.36 and 2.34 mg nitrite/L, respectively. Nitrite intoxication risk quotient suggest moderated risk to low risk to the species. Usually in production systems nitrite values are lower than safe levels suggested in this study (0.1 mg L^?1 to postlarvae and 0.2 mg L^?1 nitrite to juvenile and adults), which makes our results appropriate for the production of this species.     

Biological Effects of Pyrimethinal on Aquatic Worms (Tubifex tubifex) Under Laboratory Conditions

Laboratory studies were conducted to determine the effects of different concentrations of pyrimethinal on protein contents, and some oxidative stress in Tubifex tubifex after an exposure of 2, 4, and 7 days. Residues of the fungicide were followed in water and in the worms. In water, pyrimethinal concentration decreased slowly (maximum ?6.4 % ± 0.8 % after 2 days for 25 mg L^?1). In the worms, it increased after 4 days and decreased thereafter. LC₅₀ values were between 49.2 ± 0.58 and 39.5 ± 0.95 mg L^?1 depending on exposure time. The activity of catalase increased in response to the fungicide after 2 days of exposure to 25 mg L^?1 of pyrimethinal (+90 %). The highest decrease of glutathione-S-transferase activity (?29.7 %) was found after 7 days in the presence of 25 mg L^?1.     

Effects of [C2mim][OAc] (1-Ethyl-3-methyl-imidazolium acetate) on the Growth of Wheat Seedlings Under Cd2+ Stress

The joint effect on the growth of wheat seedlings under Cd²⁺ stress (0, 0.5 mmol L^?1) and [C₂mim][OAc] with a series of concentrations (0, 100, 200, 300, 400, 500 mg L^?1) was investigated. Physiological characteristics including superoxide dismutases, peroxidases, catalase and malondialdehyde were studied in hydroponic and soil cultures. Results indicated that, compared to samples treated under Cd²⁺ stress alone, joint treatment groups showed Cd²⁺ stress was mitigated by ionic liquid at appropriate concentrations (≤400 mg L^?1 in hydroponic treatments and ≤300 mg L^?1 in soil culture treatments). Use of inductively coupled plasma mass spectroscopy showed less Cd²⁺ in organelles in the joint treatment group. This phenomenon could be due to [C₂mim][OAc] forming metal complexes with Cd²⁺, thus reducing the amount of free Cd²⁺ available for absorption by the seedlings.     

Acute Toxicity of Copper,Zinc, and Ammonia to Larvae (Glochidia) of a Native Freshwater Mussel Echyridella menziesii in New Zealand

Adult New Zealand freshwater mussel Echyridella menziesii were collected from three locations in the North Island of New Zealand. In a series of tests that followed standard test guidance, glochidia were exposed to either dissolved copper (Cu), zinc (Zn), or total ammonia nitrogen (TAN) for 6, 24, or 48 h (20 °C, pH 7.8, water hardness 30 mg L^?1 as CaCO₃, dissolved organic carbon [DOC] 2.0–2.9 mg L^?1). Of the three contaminants and tests that met control survival criteria, mussel larvae (glochidia) were most sensitive to Cu exposure (48-h EC₅₀ = 1.7–3.4 μg L^?1, 48-h no observed effect concentrations (NOEC) of 1.3–2.6 μg L^?1). The Zn 48-h EC₅₀ concentrations were 229–337 μg L^?1 and the 48-h NOEC values were 128–240 μg L^?1. Compared with other native New Zealand species, glochidia were also relatively sensitive to TAN exposure (48-h EC₅₀ 12–15 mg TAN L^?1 [pH 7.8], 48-h NOEC 8–10 mg TAN L^?1). Comparison of our data with those of previous studies on North American freshwater mussels indicates that (1) E. menziesii are among those aquatic species most sensitive to acute Cu or TAN exposure; and (2) E. menziesii juveniles would not be adequately protected by current ANZECC water quality guidelines for TAN or Cu. Inclusion of North American juvenile mussel data in a revision of the current ANZECC water-quality guideline (95th percentile) for chronic ammonia exposure results in a decrease from 0.9 mg to 0.2 mg TAN L^?1 (pH 8).     

Toxicity of CuO Nanoparticles to Structure and Metabolic Activity of Allium cepa Root Tips

Roots of Allium cepa were exposed to six CuO NPs suspensions (0, 5, 10, 20, 40, 80 mg L^?1) in this study. Results revealed that with the increase of CuO NPs concentration, the Cu content in roots increased significantly. Compared to control, onion roots treated with CuO NPs (except 5 mg L^?1 suspension) grew slowly after 24 h. The surface of the root cap and meristematic zone were obviously damaged. The apical meristem of roots treated by 10 mg L^?1 and above concentrations stopped division. The nucleus of meristematic cells deformed, and nucleoli number increased. The plasmolysis occurred, and the cell membrane and nuclear membrane fractured. With the increase of CuO NPs concentration, the MDA content increased, and the root activity decreased. When dealt with 80 mg L^?1 CuO NPs for 72 h, onion roots appeared to be corroded.     

Cadmium-Resistance Mechanism in the Bacteria Cupriavidus metallidurans CH34 and Pseudomonas putida mt2

Cupriavidus metallidurans CH34 and Pseudomonas putida mt2 were used as cadmium (Cd)-resistant and -sensitive bacteria, respectively, to study Cd uptake, sorption, intracellular accumulation, metallothionein (MT) induction, and bioremediation potential of both isolates. According to this research work, Cd had a stimulatory effect on the growth of CH34 cells (OD₅₇₈ = 1.43) compared with mt2 cells (OD₅₇₈ = 0.8). Addition of N,N′-dicyclohexylcarbodiimide (DCCD) and 2,4-dinitrophenol (DNP) along with Cd resulted in more cell growth in mt2 (OD₅₇₈ = 0.71) compared with CH34 (OD₅₇₈ = 0.34). DCCD and DNP inhibited this active uptake only in CH34 but not in mt2. Greater Cd interaction with the cell surface was observed in mt2 cells compared with CH34 cells. Intracellular Cd accumulation was interrupted by DCCD and DNP in CH34 (only 1.81 ± 0.04 μg L^?1 at 5 h) but not in mt2 (24.41 ± 0.01 μg L^?1 at 5 h). Intracellular Cd uptake was observed in even killed mt2 cells (7.11 ± 0.05 μg L^?1 at 5 h) compared with CH34 cells (2.50 ± 0.08 μg L^?1 at 5 h). This result showed that the Cd accumulation mechanism in CH34 is ATPase-dependent, whereas in mt2 uptake mechanism is not ATPase-dependent because mt2 ATPase was not inhibited by DCCD and DNP. CH34 removed 93 mg L^?1 of Cd after 8 days from original industrial effluent, which was more than Cd removal by CH34 from distilled water (i.e. 90 mg L^?1 after 8 days). mt2 was able to remove 80 mg L^?1 of Cd after 8 days from original industrial effluent, which was more than Cd removal by mt2 from distilled water (i.e. 77 mg L^?1 after 8 days). Cd did not induce any MT in CH34, but it did so in mt2 (14 kDa), which was thought to be a Cd-resistance mechanism operative in mt2.     

Concentrations of Arsenic and Boron in Water,Sediment and the Tissues of Fish in Emet Stream (Turkey)

In this study, the concentrations of arsenic and boron were determined in the water and the sediment, as well as in the muscle tissues of Squalius cephalus, Alburnoides bipunctatus, Barbus plebejus and Capoeta tinca from Emet Stream. The fish samples were caught in May 2011 and September 2012. The metal concentrations in the water samples were as follows: arsenic was 137.1–1002 µg L^?1, and boron was 2421–14490 µg L^?1. The metal concentrations in the sediment samples were as follows: arsenic was 14.51–3317.1 mg kg^?1, and boron was 14.22–1014.01 mg kg^?1. The mean tissue concentration of arsenic was lower than the TFC and WHO limits. Boron has been identified in fish tissues at concentrations between 0.26 and 2.96 mg kg^?1. The bioaccumulation in the muscle tissues of all fish species caught from Emet Stream did not exceed the limit values.     

Exposure Assessment to Glyphosate of Two Species of Annelids

Adult mortality, biomass, fecundity and viability of cocoons were studied in Eisenia fetida and Octolasion tyrtaeum, in response to glyphosate exposure in soil. Exposure tests were carried out following USEPA procedure, with five concentrations of glyphosate in soil and a control. O. tyrtaeum was more sensitive to the highest concentration of glyphosate (50,000 mg kg^?1), with 100 % mortality by day 7 of exposure, compared with 71 % for E. fetida. Although biomass of O. tyrtaeum was significantly different between the control and 5,000 mg kg^?1 dose at day 14, E. fetida was not affected at that concentration, and only showed a significant weight loss after 7 days of exposure to 50,000 mg kg^?1. Adverse effects upon adult fecundity and cocoon viability were observed at glyphosate concentrations of 5,000 mg kg^?1 and above. Adverse effects were observed at concentrations that greatly exceeded the recommended field application rates of glyphosate.     

A Study on Cadmium Phytoremediation Potential of Water Lettuce, Pistia stratiotes L.

Aquatic macrophytes have tremendous potential for remediation of the heavy metal cadmium. The objective of this study was to investigate Cd phytoremediation ability of water lettuce, Pistia stratiotes L. The study was conducted with 5, 10, 15 and 20 mg L^?1 CdCl₂ in hydroponic system for 21 days and the Cd concentrations in the root and shoot tissues were estimated by atomic absorption spectroscopy. The values obtained were used to evaluate the bioconcentration factor (BCF), translocation factor (TF) and translocation efficiency of this plant. The plant showed high Cd tolerance of up to 20 mg L^?1 but there was a general trend of decline in the root and shoot biomass. The maximum BCF values for root and shoot tissues were 2,294 and 870 respectively, obtained for 5 mg L^?1 Cd, which indicated that the plant was a Cd hyperaccumulator. The TF maxima was found to be 0.6 and as much as 60 % root to shoot translocation efficiency was observed for 15 mg L^?1 Cd which points towards the suitability of water lettuce for removing Cd from surface waters.     

Solubility Constraints on Aquatic Ecotoxicity Testing of Anionic Surfactants

In order to develop models that can predict the environmental behavior and effects of chemicals, reliable experimental data are needed. However, for anionic surfactants the number of ecotoxicity studies is still limited. The present study therefore aimed to determine the aquatic ecotoxicity of three classes of anionic surfactants. To this purpose we subjected daphnids (Daphnia magna) for 48 h to alkyl carboxylates (C_xCO₂^?), alkyl sulfonates (C_xSO₃^?), and alkyl sulfates (C_xSO₄^?) with different carbon chain lengths (x). However, all surfactants with x?>?11 showed less than 50% immobility at water solubility. Hence, EC₅₀ values for only few surfactants could be gathered: C₉CO₂^? (16 mg L^?1), C₁₁CO₂^? (0.8 mg L^?1) and C₁₁SO₄^? (13.5 mg L^?1). Data from these compounds showed an increase in ecotoxicity with a factor 4.5 per addition of a hydrocarbon unit to the alkyl chain, and a factor 20 when replacing the sulfate head group by a carboxylate head group. Unfortunately, we could not test carboxylates with a broader variety of chain lengths because solubility limited the range of chain length that can be tested.     

Degradation Dynamics of Emamectin Benzoate on Cabbage Under Subtropical Conditions of Punjab, India

Emamectin benzoate (Proclaim 5 SG) was applied to cabbage at 8.5 and 17 g a.i. ha^?1, during the head initiation stage. A high performance liquid chromatography (HPLC) analytical method, for the determination of emamectin benzoate in cabbage, was developed. Average recoveries of emamectin benzoate ranged from 92 % to 96 % at different fortification levels (0.05, 0.25 and 0.50 mg kg^?1). The initial deposits, 0.11 and 0.21 mg kg^?1 of emamectin benzoate at 8.5 and 17 g a.i. ha^?1, dissipated below the determination limit of 0.05 mg kg^?1 in 3 and 5 days, respectively.     

Evaluation of Sediment Contamination by Heavy Metals, Organochlorinated Pesticides, and Polycyclic Aromatic Hydrocarbons in the Berre Coastal Lagoon (Southeast France)

During the last decades, the Berre lagoon, located in southeastern France, has been deeply affected by strong contaminant inputs. Surveys of surface sediment contamination have been sparsely performed since 1964 with data often disconnected with regard to time and space. To contribute to filling this gap, this study examined the pollution status of the lagoon during a 2012 sampling. Concentrations of heavy metals (HMs) (cadmium [Cd], chromium [Cr], copper [Cu], lead [Pb], and zinc [Zn]), organochlorine pesticides (OCPs), and polycyclic aromatic hydrocarbons were examined. The available seawater metal fraction was also investigated. Water from the Vaine basin (VB; stations 1 through 6) exhibited the lowest oxygen concentration (mean O₂ % saturation 38.9 %). HM loads were in the order of Zn > Cr > Pb > Cu > Cd with overall concentration ranges of 0.20–1.40 mg kg^?1 for Cd, 17.1–119 mg kg^?1 for Cr, 7.0–60.7 g^?1 for Cu, 12.0–104 mg kg^?1 for Pb, and 56.5–215 mg kg^?1 for Zn. Although HMs accumulated at levels largely exceeding their relative natural background level of 11-fold for Pb and 80-fold for Zn, their mean concentrations decreased largely to below the acceptable legal limits. HM loads were 20 to threefold the relative corresponding value of the threshold effect level benchmark of potential biological risk. Metals were only scantly released by sediments with mean percentage release of 0.99 % for Cd and 40.2 % for Cr with a peak for this latter element of 99 % in the VB sector. In the case of OCPs, sediments appeared to be significantly polluted, especially in the VB area, with a mean lindane concentration of 0.05 mg kg^?1, which is ≤fivefold the legal threshold. Among PAHs, benzo[a]pyrene exceeded the permitted limit of 0.1 mg kg^?1 mainly in the VB sector.     

Persistence Behavior of Imidacloprid and Carbosulfan in Mango (Mangifera indica L.)

Imidacloprid was sprayed on mango cv. Dashehari at 0.3 mL L^?1 of water during pre-bloom stage with 6–8 cm panicle size (first week of March) to control hopper and carbosulfan was sprayed at 2.0 mL L^?1 of water in the trees of mango hybrid (H-1000) during fruit development stage (first week of May) to control leaf webber. Residues of both the insecticides were analysed in peel, pulp and fruit at different stages of fruit development and maturity. The initial residues of imidacloprid, after 30 days of spraying, were 1.21, 0.56 and 1.77 mg kg^?1 in peel, pulp and whole fruit, respectively. The residues persisted in peel for 60 days and in pulp for 50 days and dissipated with a half-life of 38 days. Mature Dashehari fruits at harvest (after 85 days of spraying) were free from imidacloprid residues. Carbosulfan in mango peel dissipated from 5.30 mg kg^?1 (after 1 h of spraying) to 0.05 mg kg^?1 at the time of harvest (after 45 days of spraying). Carbosulfan residue in pulp was very low (0.08 mg kg^?1) after 1 h of spraying, which increased gradually to 0.90 mg kg^?1 after 10 days and finally came down to 0.04 mg kg^?1 after 26 days of spraying. The insecticide residue was not detected in the pulp at the time of harvest. The residues persisted in pulp for 26 days and in peel for 45 days and degraded with a half-life of 7 days. The dissipation of both imidacloprid and carbosulfan followed first order rate kinetics in whole fruit (peel + pulp). Therefore, the safe pre-harvest intervals were suggested to be 55 days for imidacloprid and 46 days for carbosulfan before consumption of mango fruits after spraying of these insecticides.     

Chemical and Microbial Contamination Baseline in the Saguenay–St. Lawrence Marine Park (Eastern Canada): Concentrations and Fluxes From Land-Based Sources

Stretching halfway between the Canadian Great Lakes and the Atlantic Ocean, the Saguenay–St. Lawrence Marine Park is subject to environmental issues being exposed to untreated or uncontrolled point and non-point sources of anthropogenic contamination. This article provides a first estimation of chemical and microbial contamination entering the marine park from the discharges of local municipal effluents and the inputs of tributaries in the summer period. Suspended particulate matter (SPM), nutrients, particulate carbon (PC) and nitrogen, trace metals, and fecal coliform bacteria were determined in surface brackish waters at upstream boundaries, in freshwater of 11 tributaries, and in nine sewage effluents from small communities settled along the marine park. Most tributaries have SPM < 10 mg L^?1 and contributed to a total of ~47 tons day^?1, thus representing a small proportion of daily SPM transported by Saguenay River (200 tons day^?1) and St. Lawrence River (6.3 × 10³ tons day^?1). As expected, untreated sewage effluents showed high fecal contamination (0.2–6.0 × 10⁶ CFU 100 mL^?1), high NO _x levels (4–33 μmol L^?1) and high concentrations of particulate organic carbon (7–62 mg L^?1). However, all tributaries had low coliforms (<230 CFU 100 mL^?1), low PC (0.3–1.1 mg L^?1), and low nutrients (NO _x  < 3.3 μmol L^?1), with the exception of the Moulin-à-Baude River, a small tributary (2.3 × 10⁵ m³ day^?1) clearly contaminated by human activities. Detailed analysis of 14 metals and metalloids in SPM did not show any clear contamination trend between sewage effluents and tributaries, except for Grandes-Bergeronnes River, where most trace metals appeared to be greater than for other rivers. Regarding global inputs, results showed that despite their relatively high pollutants load, inputs from local sewages and small tributaries remained minor contributors compared with upstream inputs, i.e., Saguenay River and St. Lawrence River. However, we illustrate that some local hydrodynamic factors in bays and inlets must be taken into account when evaluating risks associated with sewage discharges.     

Heavy Metal Tolerance in Metal Hyperaccumulator Plant, Salvinia natans

Metal tolerance capacity of Salvinia natans, a metal hyperaccumulator, was evaluated. Plants were exposed to 10, 30 and 50 mg L^?1 of Zn, Cd, Co, Cr, Fe, Cu, Pb, and Ni. Plant biomass, photosynthetic efficiency, quantum yield, photochemical quenching, electron transport rate and elemental (%C, H and N) constitution remained unaffected in Salvinia exposed to 30 mg L^?1 of heavy metals, except for Cu and Zn exposed plants, where significant reductions were noted in some of the measured parameters. However, a significant decline was noted in most of the measured parameters in plants exposed to 50 mg L^?1 of metal concentration. Results suggest that Salvinia has fairly high levels of tolerance to all the metals tested, but the level of tolerance varied from metal to metal.     

Sublethal Toxic Effects of Nonylphenol Ethoxylate and Nonylphenol to Moina macrocopa

The aim of this paper was to examine the sublethal toxic effects of nonylphenol ethoxylate (NP₁₀EO), its primary degradation product nonylphenol (NP), and their mixture on Moina macrocopa. Chronic toxicity tests were carried out by using sublethal chemical concentrations. Results showed that all treatments reduced the survivorship, body length, and reproduction of M. macrocopa with NP being 10 %–20 % more toxic to M. macrocopa than NP₁₀EO. Results also indicated that the toxic effects of NP₁₀EO and NP mixture on M. macrocopa were more severe than that of any single chemical alone. At the highest concentration in this experiment, 0.337 mg L^?1 NP₁₀EO plus 0.0154 mg L^?1 NP treatment caused the survivorship of M. macrocopa to zero, neonates number of reproductions to zero, 45.5 % reduction in the body length, and 88 % reduction in the total neonates number.     

Effects of Oxalic Acid on Arsenic Uptake and the Physiological Responses of <Emphasis Type="Italic">Hydrilla verticillata</Emphasis> Exposed to Different Forms of Arsenic

A hydroponic experiment was conducted to investigate the effects of oxalic acid (OA) on arsenic (As) uptake and the physiological responses of Hydrilla verticillata exposed to 3 mg L^?1 of As in different forms. Plant As(III) uptake was significantly increased by 200–2000 µg L^?1 OA. However, an increase of As(V) uptake was only shown with 1000 µg L^?1 OA, and no significant difference was observed with dimethylarsinate treatment. Peroxidase and catalase activities, and the contents of photosynthetic pigments, soluble sugar and proline, were significantly increased by 1000 µg L^?1 OA during As(III) treatment. Superoxide dismutase and proline were also increased significantly by 1000 µg L^?1 OA when plants were exposed to As(V). In DMA treatment, proline was significantly increased by 500 µg L^?1 OA. Therefore, As-induced oxidative stress is relieved by OA, but it depends on OA concentration and the form of As. Our results may be useful for the phytoremediation of waste water containing As and OA.