Effect of waste water of the pharmaceutical industries, sugar and flour mill on growth and yield of Pisum sativum L

Industries are the main source of surface and ground water pollution. Whereas, water pollution is a major cause of health hazard to human beings, animals and plants. As such, industrial effluents badly affect growth and development of food crops. In the present study, effect of the wastewater of pharmaceutical industries, sugar and flour mills was evaluated on the growth and yield of pea plant (Pisum sativum L.). Tap water was used as controlled. The field experiments were carried out during the growing season of February, 2017. The results of field experiments showed that there is no significant difference between plant germination, growth, development, plant height, number of branches per plant and seed weight (fresh and dry). Similarly, in lab experiments, no considerable difference was observed between controlled (Tap water) and wastewater treatments. We argue that small scale effluents have no effect on the growth and yield of the pea plants. It has been observed that less than 10 % of the wastewater is treated and the rest of untreated wastewater is discharged into the nearby water bodies throughout Pakistan. Therefore, proper treatment system for industrial effluents is recommended to meet the international standards.


Introduction
Industrial effluents are the major source of surface and ground water contamination. These contaminations may cause numerous diseases [1], among them, shorter life expectancy is the major adverse effect of the industrial effluents [2]. The use of industrial effluents for irrigation has emerged in the recent past because it contains sufficient quantities of NPK (nitrogen, phosphorous and potassium) along with calcium which are important nutrients for development and growth of plants [3]. As such, industrial effluents contain toxic organic and inorganic compounds [4][5][6]. Therefore, it is very necessary to study the effect of industrial wastewater on crops [7]. Industrial wastewater has been used for irrigation of food crops, pea plant (Pisum sativum L.) particularly. Pisum sativum is consumed in variety of ways throughout the globe and their demand is increasing day by day [8,9]. The increasing need of protein rich raw materials for animal feed and human nutrition have led to greater interest in pea as a protein source [10]. Green peas are good source of natural proteins and carbohydrates [11][12][13]. Pisum sativum is an annual plant, with a life cycle of one year. It is a cool season-crop grown in many parts of the world. It can be grow in the temperature range of 13 to 18 °C. The present study was designed to investigate the effect of untreated wastewater of pharmaceutical industries, sugar and flour mills on the growth and development of pea plants (Pisum sativum L.).

Materials and methods
Seeds of Pisum sativum L. were collected from herbarium of Nuclear Institute of Food and Agriculture (NIFA) Tarnab, Peshawar, Khyber Pakhtunkhwa, Pakistan. Wastewater was sampled from three points (i).
Pharmaceutical industrial zone, Hayatabad, Peshawar (ii). Naguman Flour Mill, Peshawar, (iii). Khazana Sugar Mill, Peshawar, Khyber Pakhtunkhwa. The wastewater was collected in clean plastic bottles of 10 L on daily basis. The collected wastewater was used on the same day of collection. The soil was sampled from agricultural land near Peshawar, Khyber Pakhtunkhwa, dried and homogenized by passing through sieve. The soil was stored in clean plastic bags.

Field experiments
The seeds were grown in pots. Soil of 28.50 kg was filled in each pot and five seeds of Pisum sativum were sown in one pot. Four replicates were made for each pot. 500 mL of wastewater was given to each pot daily. Whereas, tap water was used as control.

Laboratory experiments
Lab experiments were conducted using Petri dishes. Two filter papers were placed in a Petri dish and seed of the Pisum sativum was added at room temperature. One milliliter wastewater was added to the nominated Petri dishes on daily basis at around 3:00 pm to 4:00 pm. As such, 1 mL tap water was added to the Petri dishes under controlled experiment every day. The changes were observed on daily basis.

Results and discussion Field experiment
The results of growth rates, heights and seeds are shown in ( Two-way ANOVA Analysis was used for the treatments to compare them with the controlled parameter. The two-way ANOVA compares the mean differences between groups that have been split in two independent variables (called factors). The primary purpose of two-way ANOVA is to understand if there is an interaction between the two independent variables on the dependent variable. Results of statistical analysis are shown in ( Table 2). The results of statistical analysis revealed that there was no effect of Naguman Flour Mill and pharmaceutical industries wastewater treated plants on the flower appearance, plant height, number of branches, number of seeds per pod and weight of seeds. However we observed significant relation of Khazana Sugar Mill wastewater treated plants with the observed variables. The significant results of Khazana Sugar Mill wastewater treated pots showed positive relation with flower appearance, plant height, number of branches, number of seeds per pod and weight of seed. Mahvi et al. [14] showed that the using of wastewater for irrigation increases the growth parameters with the exception of aerial parts than the control. Khouri et al. [15] observed increased yield(from 28 to 51%) in wheat, rice, beans, cotton and potatoes compared with fresh water irrigation along with the application of commercial fertilizers. Khazana Sugar Mills wastewater may contain organic nutrients of the sugarcane, which might responsible for the positive relation of the treatment with the growth parameters. Effluents often contain significant quantity of organic and inorganic nutrients, such as NPK along with many toxic wastes, microorganisms [16] and induces increased antioxidant enzyme activities in plants. High concentration of nutrients in effluents contributes to high crop yields [12].

Lab experiment
The results of laboratory experiments are shown in (Table 3). The laboratory experiments were conducted to observe the initial germination of seeds treated with waste water of pharmaceutical industries, Naguman Flour Mill, Khazana Sugar Mill and tap water.  The results of statistical analysis of two-way-ANOVA are shown (Table 4). The statistical analysis revealed that there was no significance difference between controlled (tap water treated) and un-controlled (wastewater treated) treatments. The twoway-ANOVA analysis showed that wastewater treatments have no relation with the germination percentage, germination initiation, germination termination, plumule and radicle length. Kaushik & Garg [17] carried out a research on germination, detention index, physiological growth parameters and plant stains of two cultivars of Surghum. The textile wastes did not illustrate any restrict effect on seed growth at low concentration. Zille et al. [18] confirmed that the household and industrial polluted water affected the germination and growth of seeds and seedlings of different species slightly.