Effect of untreated sewage effluent irrigation on heavy metal content, microbial population and enzymatic activities of soils in Aligarh.

The study pertains to the impact of domestic and industrial sewage water irrigation on the chemical, biological and enzymatic activities in alluvial soils of Aligarh District. Results showed that soil enzymatic [dehydogenase (DHA), acid and alkaline phosphatase, urease and catalase] activities in the soils increased up to 14 days of incubation and thereafter inhibited significantly. The enzymatic activity were in the order sewage effluent > partial sewage effluent > ground water irrigated soils. Increase in soil enzymatic activities up to 2nd week of incubation was due to decomposition of organic matter. Maximum inhibition of enzymatic activities, after 14 days of incubation were found in sewage effluent irrigated soils and minimum in ground water irrigated soils. Similar trend was also seen for microbial population. Soil enzymatic activities and microbial population were significantly and positively correlated with soil organic matter. Results also indicated that the microbial population and enzymatic activities in sewage irrigated soils decreased continually with irrigation period. The average concentration of total heavy metals in sewage irrigated soils and partial sewage irrigated soils increased and was 3 and 2 times higher for Zn; 4.5 and 1.7 times higher for Cu; 3.8 and 2.4 times higher for Cr; 5.7 and 3.5 times higher for Pb; 3.5 and 2.2 times higher for Cd and 2.7 and 2.0 times higher for Ni respectively than that of ground water irrigated soils. Results also showed that though total heavy metals concentration increased with period of sewage irrigation but the concentration of diethylene triamine pentaacetic acid (DTPA) extractable heavy metals in partial sewage irrigated and sewage irrigated soils remained almost same, which might be due to deposition of heavy metals in crops grown on the soils.

Simultaneous adsorption and desorption of tetracycline and cadmium on alluvial soil of Aligarh (India).

Interaction of Cadmium (Cd) and a widely-used veterinary antibiotic tetracycline (TC), on the basis of their adsorption and desorption on alluvial soil, was studied using the batch experiments. The results indicated that adsorption and desorption isotherms of Cd and TC on the soils were well fitted with the Freundlich equation. There was an apparent sorption-desorption hysteresis of Cd and TC in soil, which will probably pose a threat to soil-environmental quality and human health. The adsorption of Cadmium or tetracycline in the combined form was more than individual. This can be attributed to increasing Cd adsorption via the bridge of TC, or stronger affinity of the TC-Cd complex to soil minerals than Cd or TC. The presence of Cd enhanced the hysteresis effect of TC sorption -desorption (H= 0.886-0.904). Similarly, the hysteresis effect of Cd sorption - desorption in presence of TC was more than Cd alone (H=0.882-0.925). The hystersis effect was more for Cd in presence of TC than forTC in presence of Cd, denoting binding of Cd on soil surface was stronger in presence of TC than Cd alone. It is thus important to consider the interaction between Cd and TC while studying on the fate of Cd and TC in soil environment.

Effect of three carbamate pesticides on population dynamics of soil microorganisms.

The response of soil microflora to increasing concentration (300 and 500 mg kg(-1) of soil) of three carbamate pesticides, viz. Oxamyl (I); S-ethyl-N(methylcarbamoyl) oxythioacetamidate (II) and N-Phenyl-4-ethylcarbamoyl propyl carbamate (III) was determined under fields conditions over a period of 91 days. After 0,7,14,21,28,35,42,49,56,63,70,77,84,91 days of application the number of bacteria, fungi, actinomycetes and protozoa population was estimated in soil. All the studied pesticides at both the rates of application initially (35-49 days after treatment, DAT) significantly decrease the population of fungi and actinomycetes and thereafter an enhancement of population occurs. Whereas bacteria population at lower dose of application initially (35-49 DAT) increased and thereafter decreased while at higher dose of pesticides population of bacteria continuously decreased. The protozoa population at both the studied concentration for all the studied pesticides decreased with time. The increase in bacteria population and decrease in population of fungi and actinomycetes up to 35-49 days may be due to stimulation of the mineralization rate of organic carbon and ability of bacteria to breakdown the pesticide and utilization of carbon source for their activity. The results also denote that activity of all the studied pesticides is almost same.

Effect of soil properties on the persistence of carbamate pesticides.

Persistence of six carbamate pesticides (oxamyl, I; carbaryl, II; phorate, III; phosphomidon, IV; carbofuran, V and methomyl, VI) on ten different soils of Aligarh district was investigated in the laboratory incubated conditions under different moisture levels; temperature; pesticide concentration; acidic, neutral and alkaline pH; FYM (farm yield manure) and nitrogen concentration. The process of degradation followed first order kinetics. The rate of degradation of all the six carbamate pesticides in studied soils was found to increase with rise in temperature, moisture content, amount of FYM or N and decrease with increasing pesticidal concentration. The degradation was more rapid in alkaline medium than neutral or acidic medium. The values of activation energies (Ea) showed that the degradation of pesticides in soils is due to microbial activity and probably enzymatic. The degradation of pesticides was in the order I > VI > V > IV > II > III. The degradation of pesticides in different soils was in the order S1 > S2 > S3 > S4 > S5 > S6 > S7 > S8, > S9 > S10.

Effect of different organic materials on maize at different concentrations of lead.

The present study has been undertaken to know the effect of concentrations of lead (Pb) and different organic materials on the maize yield, concentrations of lead on maize plants and diethylene triamine penta-acetic acid (DTPA) extractable lead (Pb) on the post harvested soils. The results revealed that growth of maize increased by adding lead (Pb) upto 25 mg kg(-1) soil and thereafter the growth decreased. Application of organic matter increased the growth of maize in Pb-contaminated soil. With the increase in Pb concentration in soil, the concentration of Pb in plants also increased, however, application of organic material decreased Pb concentration in maize. The concentration of DTPA extractable lead (Pb) in post harvested soil samples significantly and consistently increased with increase in Pb. The addition of organic manure decreased the DTPA extractable Pb in soil which might be due to complexation/chelation of Pb with organic matter.

Kinetics of interaction of three carbamate pesticides with Indian soils: Aligarh district.

The kinetics of interaction with soil of three carbamate pesticides (I, II, III) used as nematicides and herbicides was studied at four different temperatures from solutions of six soil samples of Aligarh district. The values obtained for rate constants for adsorption and desorption were in good agreement with those obtained from the Lindstrom model, which proved useful in the simultaneous evaluation of adsorption (k1) and desorption (k2) rate constants. The rate constants for pesticides were in the order III > I > II on all the six soil samples. The data for rate constants, activation energies, heats of activation, entropy of activation and thermodynamic parameters indicated a partly physical and partly chemical adsorption of pesticide on the soil surfaces. Adsorption occurred via coordination and/or protonation of the exchangeable cations with the amidic carbonyl group, and hydrogen bonding and dipole association at the crystal edge and basal surfaces. The adsorptivity of the soils may be attributed to the organic matter content and percentage clay content.

A study of disseminated intravascular coagulopathy in hepatic coma complicating acute viral hepatitis.

Thirty cases of viral hepatitis with and without coma and 15 normal healthy age and sex matched controls were studied for disseminated intravascular coagulopathy (DIC). Cases of viral hepatitis with coma showed strong evidence of DIC in the form of increased plasma FDP (240 +/- 190.64 dilution), diminished fibrinogen half life (48.1 +/- 15.3 hours) and increased fractional catabolic rate (46.13 +/- 14.7% per day) with normal Euglobulin clot lysis time and reduced fibrinogen (147.33 +/- 43.5%) and platelet count (1.27 +/- 0.324 lakhs/cm.). The possible role of heparin in the reversal of coagulation abnormalities have been discussed.