Microfauna Community as an Indicator of Effluent Quality and Operational Parameters in an Activated Sludge System for Treating Piggery Wastewater

In order to study the potential use of microfauna as an indicator of effluent quality and operational parameters in an activated sludge system for treating piggery wastewater, an experimental sequencing batch reactor was set up and evaluated by biological and physical–chemical analyses for 12 months. Results show that microfauna (and specifically ciliate protozoa) are a good parameter for assessing effluent quality in terms of both chemical oxygen demand (COD) and ammonia and for assessing the organic and nitrogen load of the system. Specifically, the abundance of ciliates decreases from 20,000 individuals·mL^?1 to ca. 2,500 individuals·mL^?1 and from ca. 10,000 individuals mL^?1 to ca. 200 individuals mL^?1 when effluent concentration is between 550 and 750 mg L^?1 and above 100 mg L^?1 to the COD and ammonia concentrations, respectively. Furthermore, microfauna abundance is reduced from ca. 18,000 individuals mL^?1 (organic load between 0.1 and 0.2 mg COD mg total suspended solids (TSS)^?1 day^?1) to ca. 500 individuals mL^?1 (organic load between 0.3 and 04 mg COD mg TSS^?1 day^?1). Microfauna abundance also decreases as nitrogen loading increases. Nitrogen loading in the range of 5–60 mg NH₄–N g TSS^?1 day^?1 does not have any significant effect on microfauna abundance. However, ammonia loading from 60 to 120 mg NH₄–N g TSS^?1 day^?1 reduces microfauna abundance ca. 6-fold. Ciliate protozoa were the largest microfauna group during the whole period of study, representing ca. 75% of the total microfauna abundance. The largest group in the ciliate community was that of the free-swimming ciliates. This was followed by the group of attached and crawling ciliates. Specifically, the dominant ciliate species during the whole study period were Uronema nigricans, Vorticella microstoma-complex, Epistylis coronata, and Acineria uncinata.     

Cadmium accumulation in eurasian watermilfoil plants

The aquatic vascular plant Eurasian watermilfoil (Myriophyllum spicatum L.) was investigated for its potential to take up Cd from nutrient-rich water in a short-term growth and harvest regime. Eurasian watermilfoil plants were grown in and harvested weekly from 0.10M Hoagland nutrient solutions containing concentrations of Cd from 0.04 to 7.63μg Cd mL^?1. Dry weights of plants significantly decreas4ed when exposed to 7.63μg Cd mL^?1. For both 0.04 and 1.03μg Cd mL^?1 treatment the greatest concentration of Cd in plants occurred during the first two weeks. The greatest Cd concentration of Cd in plants for the 7.63μg Cd ML^?1 treatment occurred during week one and decreased through week 2. Tissue P concentration in control plants increased over time but did not increase significantly over time when plants were exposed to 0.04 and 1.03μg Cd mL^?1 levels. Tissue P concentration decreased over time when plants were exposed to 7.63μg Cd mL^?1. Stem length, root dry weights, and root number significantly increased over time in control plants and in those exposed to the 0.04 and 1.03μg Cd mL^?1 treatments. Plants treated with 7.63μg Cd mL^?1 did not grow. These results suggest that Eurasian watermilfoil would be useful for absorbing Cd from nutrient-rich water when the solution concentration was in the range of 0.04 to 7.63μg Cd mL^?1. However, in solutions having the highest concentration of Cd, the harvest regime would have to sustain plant vigor, avoid tissue Cd loss, and realize maximum uptake of Cd from solution.     

Contamination of bela krajina,Slovenia with polychlorinated biphenyls 1. Levels of some high molecular chlorinated hydrocarbons in the water and fish of the Kupa River in Croatia

It is well documented that synthetic chlorinated hydrocarbon residues are widespread throughout the world ecosystem. Recently serious contamination of the Kupa River in Slovenia resulting from improper disposal of the waste disharged by an electro-capacitor manufacturing plant was observed. The migration of the PCBs from the waste tip into the karst ground water and source water has been established. PCBs have been also introduced into the small Lahinja River a tributary of the Kupa. Consequently, these pollutants have been detected in the Kupa river. An investigation of the levels of chlorinated hydrocarbons in tap water, water and fish samples collected from 1985 to 1988 from the Kupa River in the region of Petrinja and Sisak was performed. This region is about 200 km downstream of the primary contamined area. Concentrations of chlorinated insecticides and polychlorinated biphenyls in tap water ranged from <0.2 to 5.0 ng dm^?3 for PCBs such as Aroclor 1254 and from <0.4 to 10.4 ng dm^?3 for PCBs such as Pyralene 1500. In the Kupa River, water samples were found with PCBs such as Aroclor 1254 from <1.5 to 5.0 and from <2.6 to 104 ng dm^?3 for PCBs such as Pyralene 1500. The level of the investigated chlorinated insecticides were under the sensitivity limits of 0.05 for dieldrin and 0.1 ng dm^?3 for DDTs. Concentrations of chlorinated insecticides and polychlorinated biphenyls in the fish samples were several orders of magnitude higher in comparison with the water samples and ranged from the sensitivity limit for dieldrin (<0.0001) to 0.0034 mg kg^?1; p,p'DDT from 0.0003 to 0.0076 mg kg^?1; p,p'DDE from 0.0004 to 0.1752 mg kg^?1; p,p'DDD from 0.0001 to 0.0201 mg kg^?1 wet weight. Concentrations of PCBs were significantly higher and ranged from 0.015 to 2.742 mg kg^?1 wet weight for Pyralene 1500 and from 0.090 to 1.590 mg kg^?1 for Aroclor 1254 +Aroclor 1260.     

Residues of organochlorine pesticides in fish from the Arabian Gulf

High-resolution electron capture gas chromatography was used to determine residue levels of organochlorine pesticides in 13 commercially important fish species collected from the NW Arabian Gulf. While most of the residues were below the detection limit of 1 μg kg^?1 wet weight, relatively low concentrations of ΣDDT, endrin and dieldrin were detected in the edbile tissue of these fishes. The ΣDDT residue levels ranged from 2 to l 1μg kg^?1 wet weight, endrin ranged from none detected (nd) to 45 μg kg^?1 and dieldrin from nd to 5 μg kg^?1. A definite correlation was established between total organochlorine pesticide residues and lipid content (r = 0.6) for the NW Arabian Gulf fishes. Comparison with fish from Hor-al-Hammar Lake (an area that used to be sprayed with pesticides) has shown that the latter contained significantly higher residue levels. The ΣDDT residue levels ranged from 5 to 45 μg kg^?1 wet weight, endrin from 3 to 83 μg kg^?1 and dieldrin from nd to 4 μg kg^?1 Based upon the observation that the original DDT (p, p′-DDT) was identified in the NW Arabian Gulf fishes, it has been concluded that there was a recent input of DDT to this region. Since DDT application has been banned in Iraq, consequently it was assumed that DDT must originate from a more remote source.     

Short-Term Effects of Arsenate-Induced Toxicity on Growth, Chlorophyll and Carotenoid Contents, and Total Content of Phenolic Compounds of Azolla filiculoides

This study evaluated the toxic effects of arsenic (As) on the growth, total antioxidant activity, total content of phenolic compounds, and content of photosynthetic pigments of Azolla filiculoides. The aquatic fern was propagated and exposed to Yoshida nutrient solution contaminated with sodium arsenate (Na₂HAsO₄??7H₂O) at six concentrations (5, 10, 20, 30, 60, and 120???g?As?mL^?1), including the control without As contamination. Azolla cultures were kept under environmental chamber conditions?26??C, 12?h photoperiod and 80% HR for 96?h. Increased As concentrations (>30???g?mL^?1) significantly diminished growth of A. filiculoides and the total content of chlorophyll and total phenolic compounds, but significantly enhanced of total carotenoid?+?xanthophylls content. The concentrations of 5 and 10???g?As?mL^?1 significantly stimulated the growth of A. filiculoides. This aquatic fern tolerates As concentrations lower than 30???g?mL^?1, and its maximum As accumulation (28???g?g^?1 dry weight) was achieved when exposed to 60???g As mL^?1, but showing clear symptoms of As toxicity.     

Concentrations and Exports of Fecal Indicator Bacteria in Watersheds with Varying Densities of Onsite Wastewater Systems

The research goal was to determine if onsite wastewater system (OWS) density had an influence on the concentrations and watershed exports of Escherichia coli and enterococci in urbanizing watersheds. Eight watersheds with OWS densities ranging from <?0.1 to 1.88 systems ha^?1 plus a watershed served by sewer (Sewer) and a mostly forested, natural watershed (Natural) in the Piedmont of North Carolina served as the study locations. Stream samples were collected approximately monthly during baseflow conditions between January 2015 and December 2016 (n?=?21). Median concentrations of E. coli (2014 most probable number (MPN) 100 mL^?1) and enterococci (168 MPN 100 mL^?1) were elevated in streams draining watersheds with a high density of OWS (>?0.77 system ha^?1) relative to watersheds with a low (<?0.77 system ha^?1) density (E. coli: 204 MPN 100 mL^?1 and enterococci: 88 MPN 100 mL^?1) and control watersheds (Natural: E. coli: 355 MPN 100 mL^?1 and enterococci: 62 MPN 100 mL^?1; Sewer: 177 MPN 100 mL^?1 and 130 MPN 100 mL^?1). Samples collected from watersheds with a high density of OWS had E. coli and enterococci concentrations that exceeded recommended thresholds 88 and 57% of times sampled, respectively. Results show that stream E. coli and enterococci concentrations and exports are influenced by the density of OWS in urbanizing watersheds. Cost share programs to help finance OWS repairs and maintenance are suggested to help improve water quality in watersheds with OWS.     

Effects of a chromated-copper-arsenate wood preservative on the growth of a pentachlorophenol degrading bacterium

A chromated-copper-arsenate (CCA) wood preservative was tested for toxic effects on the growth of a bacterial culture (Flavobactenum sp. ATCC 53874) capable of biodegrading pentachlorophenol, another wood preservation chemical. Both a commercially available CCA preparation and a laboratory-prepared CCA solution were tested. Each had an inhibitory effect on the growth of Flavobacterium at diluted CCA levels as low as 1.0×10^?4 to 1.0×10^?5% wt vol^?1. The commercial formulation was generally more toxic. EC₅₀ values calculated after 96 hr of incubation were 1.2 ×10^?4% wt vol^?1 for the commercial material (containing 0.15/0.097/0.14 μg mL^?1 of Cr/Cu/As, respectively) and 3.8×10^?4% for the laboratory solution (containing 0.51/0.31/0.49 μg mL^?1 of Cr/Cu/As, respectively). CCA toxicity increased during the first 7 to 8 days and then slowly decreased for the balance of the 21 day incubation period. Biodegradation of pentachlorophenol residues in contaminated soil will be negatively affected by the presence of CCA as a co-contaminant.     

Cadmium accumulation and bioavailability in Coontail (Ceratophyllum demersum L.) plants

The aquatic vascular plant (Ceratophyllum demersum L.) was investigated as a potential biological filter for removal of Cd from wastewaters. Plants were grown in and harvested weekly from 0.10 M Hoagland nutrient solutions containing concentrations of Cd from 0.01 to 1.03 μg Cd mL^?1. Tissue Cd was positively correlated to increased concentrations of Cd in solution. Concentration factors (CFs) of Cd in plants after one week were 13.3 for the 0.01 μg Cd mL^?1 treatment; 451.4 for plants treated with 0.04 μg Cd mL^?1, and 506.5 for plants treated with 1.03 μg Cd mL^?1. Plants treated with 0.01 μg Cd mL^?1 sustained tissue Cd concentrations almost 9-fold over those at week 1. However, after 5 weeks tissue Cd concentration in plants exposed to 1.03 μg Cd mL^?1 had decreased 97% compared to the week 1 concentration. Growth measurements of dry weight, stem lengths, and lateral shoot growth were nagatively correlated to increased Cd treatments. Our results suggest that Coontail exposed to very low Cd concentrations (0.01 μg Cd mL^?1) can take up and accumulate Cd. However, plants exposed to Cd at 0.04 μg Cd mL^?1 or above did not accumulate Cd past one week.     

Effects of a Simulated Agricultural Runoff Event on Sediment Toxicity in a Managed Backwater Wetland

We examined the effects of an amended mixture of three pesticides, atrazine (72.7?g), S-metolachlor (54.5?g), and permethrin (both cis and trans isomers; 11.4?g), on 10-day sediment toxicity to Hyalella azteca in a managed natural backwater wetland after a simulated agricultural runoff event. Sediment samples were collected at 10, 40, 100, 300, and 500?m from inflow 13?days prior to amendment and 1, 5, 12, 22, and 36?days post-amendment. Background pesticide concentrations ranged from <1 to 977, <1 to 119, and <1 to 2???g?kg^?1, for atrazine, S-metolachlor, and permethrin, respectively. Average post-amendment atrazine and S-metolachlor were 2,915?C3,927 and 3?C20???g?kg^?1, respectively at 10?C40?m and 538?C872 and <1???g?kg^?1, respectively at 300?C500?m. Average post-amendment permethrin was 65?C200???g?kg^?1 at 10?C40?m and 1?C10???g?kg^?1 at 300?C500?m. H. azteca 10-day survival varied spatially and temporally up to 100?m from inflow. Animal growth, independent of survival, was reduced 40 and 100?m from inflow on day?36, showing continued sediment toxicity of up to 100?m from inflow more than 1?month after amendment. Animal survival and growth were unaffected at 300 and 500?m from inflow throughout the study period. Correlations of pesticide concentrations and H. azteca responses indicated that observed sediment toxicity was primarily from permethrin with potential additional synergistic toxicity from atrazine and methyl parathion. Study results indicate that natural backwater wetlands can be managed to ameliorate pesticide mixture 10-day sediment toxicity to H. azteca within 300?m of inflow and smaller wetlands (??100?m) may require several months of effluent retention to mitigate effects.     

The effects of mercury,copper, and zinc on calcium uptake by larvae of the clam,mulinia lateralis

A sensitive and rapid bioassay system using Ca-45 uptake by larvae of Mulinia lateralis as indicator is described. The values of Ca uptake per larva^?1 versus elapsed time were linear and some of the Ca uptake rates, expressed as pg Ca larva^?1 h^?1, were 148.2 (no added heavy metal), 114.4 (20 µg kg^?1 of added Hg), 89.7 (200 gg kg^?1 of added Zn) and 20.5 (40 µg kg^?1 of added Cu). Linearities were also obtained by plotting log of Ca uptake per larva^?1 against heavy metal concentrations. A new terminology, ^xCa _inf50 ^supt , was proposed which expressed the concentration of heavy metal, x, causing 50% depression of Ca uptake over the exposure time, t. For Cu, Hg, and Zn, the values of ^x Ca _inf50 ^sup72h were 18.5, 26.5 and 176.0 µg kg^?1 respectively, which were comparable to the published values of LC₅₀. The effectiveness of Ca uptake depression on a weight basis was Cu > Hg > Zn, and the same sequence was also observed for larval mortalities.     

Monitoring Estrogen Compounds in Wastewater Recycling Systems

We determined the concentrations and residue patterns of 20 persistent organochlorine pesticides (OCPs), including hexachlorocyclohexanes (HCHs), hexachlorobenzene, dichlorodiphenyltrichloroethanes (DDTs), chlordane-related compounds (CHLs), mirex, dieldrin, endrin, and aldrin, in muscle of rainbow trout from Lake Mashu, Japan. Total concentrations of OCPs varied from 1.0 to 132 ng g^?1 lipid weight. α-HCH was the most prevalent OCP contaminant in the fish muscle. Using the daily fish consumption in Japan (95.2 g), the mean weight of a Japanese adult (50.0 kg), and residual pesticide concentrations, we calculated the estimated daily intakes of γ-HCH, DDTs, CHLs, and dieldrin for humans to be 0.39, 0.48, 0.68, and 0.08 ng kg^?1 day^?1, respectively. Judging from acceptable daily intakes established by the Food and Agriculture Organization of the United Nations and the World Health Organization, we believe that these OCP levels would not adversely affect human health.     

Effects and relative toxicity of heavy metals on Cuscuta reflexa

The effects of four concentrations (0.5, 1, 5 and 10 μg mL^?1) of the heavy metals Hg, As, Pb, Cu, Cd, and Cr on some senescence variables of Cuscuta reflexa Roxb. were studied. All of the treatments, except 0.5 μg mL^?1, decreased Hill reaction activity, chlorophyll and protein contents and dry matter percentage in biomass and increased tissue permeability over control data. The harmful effects of the metals were best visible at 10 μg mL^?1. The general order of sensitivity was As > Cd > Pb > Hg > Cu > Cr (absolute metal concentration). The data suggest that Cuscuta reflexa shows tolerance to the heavy metals tested up to 0.5 μg mL^?1.     

Potential significance of insects in the removal of contaminants from aquatic systems

Larvae of many aquatic insects live on or in sediments and thus come into contact with contaminants which accumulate there. The larvae may bioconcentrate these contaminants in their tissues and when they emerge as adults may transport contaminants out of the aquatic system. A simple model was developed to consider the potential significance of this transport for three levels of insect production (100, 15 and 1 g m^?2 yr^?1) and three bioconcentration factors (10000, 1000 and 100X). The period of time it would take insects to remove 50% of contaminants from a sediment layer 30 cm thick was estimated to range from 1.2 yr for conditions of high production and a bioconcentration factor of 10000 to 12000 years for conditions of low production and a bioconcentration factor of 100. Moderate levels of production, coupled with bioconcentration factors of 10 000 and 1000, would result in removal of 50% of contaminants in 8 and 80 yr. Contaminants bioconcentrated in tissues of adult aquatic insects may enter into terrestrial food webs and could be biomagnified still further as they pass from lower to higher trophic levels. Because this evaluation was based on several assumptions and a selected set of conditions, the significance of insects in a particular situation must be determined on a case-by-case basis.     

Determination of Available Cadmium and Lead in Soil by Flame Atomic Absorption Spectrometry after Cloud Point Extraction

A cloud point extraction (CPE) procedure has been developed for the determination of available cadmium (Cd) and lead (Pb) in soil by flame atomic absorption spectrometry. The proposed method was based on the CPE of a complex from ammonium pyrrolidine dithiocarbamate (APDC) and metal Cd and Pb using emulsifier octyl polyethylene glycol phenol ether (OP) as surfactant. Conditions that would affect the complex formation and separation were researched in detail, including extraction conditions as well as pH, amount of the chelating agent, concentration of the surfactant, equilibration temperature and time, and salt effect. Under the optimized conditions, both of the calibration graphs were linear in range of 0–1.0 μg mL^?1 with detection limits of 0.29 ng mL^?1 for Cd and 2.10 ng mL^?1 for Pb. The relative standard deviation (RSD) for 11 replicate measurements at 0.10 μg mL^?1 of Cd and Pb were 2.18% and 4.04%, respectively. The enhancement factors were 48.8 and 61.6 for Cd and Pb, respectively. The recoveries of Cd and Pb at the spiking level of 0.10 μg g^?1 in soil samples were from 91.7% to 115% and from 91.0% to 115%, respectively. The proposed method has been applied to the determination of available Cd and Pb in soil.     

Evaluation of the pollution by organochlorinated compounds (polychlorobiphenyls and pesticides) and metals (Cd,Cr, Cu and Pb) in the water and in the zebra mussel (Dreissena polymorpha pallas) of the river Seine.

The relationships between some organochlorines and metals in the water and in the zebra mussel of the river Seine have been studied in the Parisian area. The bioconcentration of PCBs by the mussel (Kb = 17 × 10³) was about 10 fold higher than for other organochlorines. The accumulation and the release response of the mussel to alterations of the water organochlorine levels occurred within a period smaller than 7 days. The correlation between the water and the mussel levels is highly significant for γHCH and PCBs (r=0.94, p<0.01 and r=0.87, p<0.05, respectively). The Pb bioconcentration (0.15 × 103) was about 20 fold lower than the Cu and Cr (3.4 and 3.0 × 10³, respectively). The Cu and the Pb levels in the water and in the mussel followed a parallel course. Cu and Pb appear to be taken up and released relatively rapidly within a 7 day period. Comparisons between the different stations along the river Seine showed that the highest pollutant evels in the water were found downstream Paris and were fairly well reflected by the mussel levels. However, when pollution reaches top values, the mussel metabolic activities are affected and thus, the bioconcentration ability too.     

Organochlorine pesticide contents of tributaries into Blanca Bay,Argentina

Thirteen 1-L replicate water samples from streams emptying into Blanca Bay, Argentina, were taken to study the environmental quality of the surface waters. Out of tests for eleven chlorinated pesticides, five were detected in all the sampling places as both dissolved and adsorbed species: alpha-HCH, gamma-HCH (lindane), heptachlor, delta-HCH, and aldrin. The concentrations were in the following ranges: alpha-HCH = 3 to 68 ng L^?1 and 9 to 239 ng g^?1, lindane = 2 to 42 ng L^?1 and 10 to 542 ng g^?1, heptachlor = 5 to 32 ng L^?1 and 9 to 390 ng g^?1, delta-HCH = 1 to 10 ng L^?1 and n.d. to 87 ng g^?1, and aldrin = 1 to 7 ng L^?1 and n.d. to 33 ng g^?1 for filtered water and suspended matter samples, respectively. Heptachlor epoxide, dieldrin, o-p′ DDD, and p-p′ DDT were found to be present in solution at only one sampling site whereas p-p′ DDD and o-p′DDT were not detected. The analyses revealed a non-uniform distribution of these compounds over the studied area. The higher concentrations of organochlorines were detected downstream urban areas.     

Uptake Kinetics of As, Hg, Sb, and Se in the Aquatic Moss Fontinalis antipyretica Hedw

Laboratory experiments were carried out to study the uptake kinetics of selected metals and metalloids in the aquatic moss Fontinalis antipyretica. For this purpose, moss specimens from a clean site were exposed to concentrations of As, Hg, Sb, and Se ranging from 0.1 to 10,000???g?l^?1, for incubation times of between 1 and 22?days, and the tissue concentrations of the metals in the moss specimens were then measured. Uptake kinetics followed different patterns in relation to exposure time, although the most common was Michaelis?CMenten kinetics. On the contrary, the contamination factors followed very similar patterns in relation to the exposure concentrations in all cases, with a good fit to logarithmic equations. The bioconcentration factors tended to decrease as exposure concentration increased. The bioconcentration factors for Hg were extremely high, even at the lowest concentration in water and for the shortest incubation time, which implies that F. antipyretica has a high capacity to magnify Hg levels in water, which is an important characteristic in a good biomonitor. According to the time to reach equilibrium, the minimum exposure time recommended for use in active biomonitoring by means of transplants is very variable, although high levels of the elements, except Sb, were found in the moss tissues within a few days. We do not recommend the use of this moss species to biomonitor low concentrations of Sb in water. The differences in maximum contamination factors and lowest bioconcentration factors suggest that As and Se were the most toxic of the elements under study.     

Single and Combined Effects of Cadmium and Zinc on Carrots: Uptake and Bioaccumulation

ABSTRACT

The present study was conducted to evaluate the effects of different concentrations of cadmium (Cd) and zinc (Zn), singly and in combination, on uptake and bioaccumulation of Cd and Zn in Daucus carota L. (carrot) grown under natural field conditions. Carrot plants were treated with two Cd concentrations (10 and 100 μg mL^?1), two Zn concentrations (100 and 300 μg mL^?1), and two combined concentrations of Cd and Zn (10 + 100 and 100 + 300 μg mL^?1) 15 d after seed germination. Treatments were repeated at 10 d intervals up to 90 d of plant age. A control was also kept without a Cd or Zn treatment. Uptake, total accumulation rate (TAR), bioconcentration factor (BCF), primary transport index (PTI), secondary transport index (STI), and accumulation of Cd and Zn in root, stem, and leaf were quantified. The results show that uptake, TAR, and accumulation of Cd and Zn are concentration-dependent phenomena. Highest accumulation of Cd and Zn was found in the root, followed by the stem and then leaves. The results also showed that bioaccumulation of Cd in root, stem, and leaf was greater at the low metal-application rates of Cd and Zn in combination than at the higher rate. This study further showed that interactions of Zn and Cd are dependent on the concentrations of those metals in the soil.     

Effect of the herbicide fluazifop-butyl on fungal populations and activity in soil

The side effects of fluazifop-butyl on soil fungal populations and oxygen uptake were studied by incubating soil samples with a range of fluazifop-butyl concentrations (0, 0.6, 3 and 6 μg g^?1) over 8 weeks. Cellulose decomposition in soil was also studied in laboratory experiments with the herbicide which was either incorporated in soil or sprayed onto calico squares which were buried in soil. The mycelial dry weight of six fungal species under the effect of the herbicide was also examined. Fluazifop-butyl had no significant effect on total fungal propagule populations at 0.6 μg g^?1. At 3 and 6 μg g^?1, it caused temporary reduction in fungal populations observed after 1 and 2-wk of incubation. The herbicide had no significant effect on OZ uptake. The decay of calico buried in herbicide-treated soil was generally stimulated, while the decomposition of herbicide-treated calico, buried in untreated soil, was temporary delayed. The mycelial dry weight yields of Aspergillus favus (at 2 and 12 μg mL^?1 of fluazifop-butyl) and Cunninghamella echinulata (at 12 μg mL^?1) were significantly increased. At 24 μg mL^?1 the mycelial dry weight of A. flavus and Alternaria alternata was significantly reduced.     

Studies of uptake and toxic effects of NI (II) on Salvinia natans

The uptake of Ni (II) and toxic effects of the metal on some biochemical parameters in Salvinia natans L. were studied. The uptake of Ni (II) by the plants gradually increased with increase in concentration of Ni (II) in the culture medium. Maximum accumulation of Ni (II) was noted within a day and maximum removal (about 90%) was recorded upto 20 Μg mL^?1 of Ni (II). Accumulation of the metal in roots (14.75 Μg mL^?1) is greater than that of shoots (5.25 Μg mL^?1). Ni (II)>10 Μg mL^?1 promoted senescence of Salvinia plants by decreasing chlorophylls, protein, amino acid, Hill activity, dry weight and by inducing necrosis. In the absence of other pollutants, Salvinia plants may be used for removal of Ni (II) from effluents and also as an indicator of Ni pollution.