The research work reported in this thesis was conducted during 1995 to 1998 in the premises of Soil Fertility Survey and Soil Testing Institute, Rawalpindi. Two types of soil, i.e., silt loam and sandy loam were selected from Hatiar Industrial Estate. For this purpose, initially a survey of soil types of the estate was conducted.
Composite samples of Missa series from the vicinity of Dingi village were collected. This soil is a representative soil of silt loam. Soil samples of Rajar series were collected from the fields located near Tube well stop. The soil is a representative soil of Sandy loam. These composite soil samples were brought to the laboratory and were air dried. After air drying these were filled in pots. Three wheat crops, i.e., 1995-96, 1996-97 and 1997-98 were grown consecutively. After wheat in the same pots, maize was grown in 1998. In the same soils, a separate set was used to grow eucalyptus plants for the three continuous years. The system of layout was completely randomized design with three replications. The crops and plants were raised by using different treatments of effluents of Textile Industry, Chemical Industry and Juncture of the outlets from these industries which were gathered along with city sewage of Rawalpindi nullah Lai from time to time. The effluents were analysed for chemical (pH, EC, Total Soluble Salts, BOD, COD), nutritional (total nitrogen, Ca, Mg, Na and heavy metals (Zn, Cu, Fe, Mn and Pb) contents. Soil samples before sowing of crops I plants were analysed for texture, pH, EC, SAR, O.M., nitrogen, available P, extractable K, Ca, Mg, Zn, Cu, Fe, Mn and Pb. The yield and yield parameters data, i.e., plant height, fresh weight, dry weight and grain yield of crops I plants was also recorded like effluents and soil samples and crops I plants samples were analysed for total nitrogen, available P, extractable K, Ca, Mg, Zn, Cu, Fe, Mn and Pb contents. The results are summarized below.
The chemical analysis of effluents used showed that the pH of effluents from ghee and textile industry was higher than recommended standards of National Environment Quality Standards (NEQS). The total soluble salts of effluents from Ghee industry were again higher than recommended standards of NEQS, those from textile fall inside of the periphery of permitted zone. The Residual Sodium Carbonate (RSC) of the Ghee industry was the highest followed by that of juncture effluents. Although the carbonates were not in higher concentration yet t he amount of bicarbonates present i nail the effluents render them unfit for irrigation purpose. Calcium and Magnesium (Ca + Mg) concentrations of the effluents were also determined. The Biological Oxygen Demand (BOD) of all the effluents is much higher than that permissible under law. Again the Chemical Oxygen Demand (COD) of all the effluents except that from chemical industry was higher than that recommended by the NEQS. The total amount of heavy metals exceeded 2 mg/L in all the industrial effluents which have been established as upper limit by the environmental statues. Keeping only this factor in view, these effluents should not be allowed to consume by living organisms including plants and their media i.e., soil. The original soil analysis showed that the pH of the soils makes them alkaline. The ECe and TSS are in suitable range. Generally both the soils are low in organic matter. However, the organic matter and Nitrogen contents of sandy loam are lower than those in silt loam. Both the soils have enough Potassium while Phosphorus was low and very low in soil No.! and 2 respectively.
The post-harvest analysis showed that the irrigations with the effluents could not alter the soil texture. In some treatments in wheat, maize and eucalyptus raised ECe and TSS of the soils increased. Maximum increase was observed in textile effluent irrigated silt loam soil. In case of wheat, the salt accumulation in soil was the lowest. In case of sandy loam, the pH also increased over that of tap water and prior levels of the soils under all the three crops.
Organic Matter and Nitrogen concentrations were found to be higher in the soils irrigated with the higher concentrations of the effluents. The highest organic matter and Nitrogen accumulation was observed in the soil irrigated with effluents of ghee industry. The Potassium contents of sandy loam soil (soil No.l) were higher than those in the silt loam soil (Soil No.2) after the harvests of plants. The heavy metal contents of sandy loam soil were higher than those in silt loam soil in most of the treatments. When the plants were compared, the accumulation of heavy metals were higher in wheat grown soil than that in maize. Eucalyptus grown soil fell in between these two.
The crop I plant results showed that most deleterious effect on grain yield was shown by the ghee effluents which caused sterility and plant death in wheat of third year. Different treatments depicted different effects on plant height, fresh and dry weight and grain yield. Two soil types were also responsible for these effects. The short-term application of effluent irrigation was a visible increase in the yield parameters over the control. However, the long term application proved to be deleterious. The higher organic matter and trace elements present in the effluents caused the initial increase, however, the cumulative effects of trace elements was retardation of plant machinery in generations to follow especially the enzymes. No visible toxic effects were noted on plants in most of the cases, however, in pure ghee effluents, sterility in wheat and low yield in maize was visible.
Plant analysis for Na, K, Ca and Mg was also carried out for three wheat, three maize and eucalyptus crop. Sodium uptake by the plants decreased in control during the consequent years over the first year crop. Sodium concentrations were higher in roots and shoots during succeeding years than the first year and they were R oot>Shoot>grain in all the treatments. Root, Shoot and grain K accumulation decreased in succeeding years in all the treatments. Ca content of roots of wheat increased during succeeding years over the previous years. Grain fixed least amounts of Ca. The Mg contents of grain were the lowest among the alkali and alkaline earth metals in the plant parts. The pattern of accumulation remained NaK>Mg>Na in most of the experiments. In wheat, the accumulation trend remained as Zn > Mn > Fe > Pb > Cu > Ni whereas in Maize it was Fe > Zn > Mn > Pb > Ni > CU. In eucalyptus, the accumulation was as Mn > Zn > Fe > Pb > Cu > Ni with a few exceptions.