Phytotoxic effects of two commonly used laundry detergents on germination, growth, and biochemical characteristics of maize (Zea mays L.) seedlings.

Laundry detergents, a mixture of different compounds, are used as washing agents in houses and cleaning agents in institutions and industries. As a result, industrial and domestic wastewater usually contains detergent contamination in variable amount. In many developing countries, untreated municipal and industrial wastewater is used for irrigation of crops. There is a possibility that laundry detergents and their ingredients present in irrigation water may affect plant growth as reported in several plant species. However, studies on the effects of laundry detergents on important cereal crops like maize can rarely be found in literature. Therefore, the present study was conducted to evaluate the effects of two commonly used commercial laundry detergents on germination, root-shoot length, fresh biomass, leaf number, leaf width, cell viability, cell injury, light-harvesting pigments, protein contents, and ion concentration in maize (Zea mays L.) seedlings. The obtained results revealed that both the detergents in the tested concentration range (1-500 mg L-1) did not significantly affect seed germination in maize. Similarly, shoot growth, leaf number, and leaf width were not significantly affected by detergents, while in the case of root, one detergent promoted root growth while the other one inhibited it. Both the detergents caused a slight increase in total soluble proteins, and this effect was significant at the highest tested one or two concentrations of detergents (100 and 500 mg L-1). Chlorophylls a and b and total carotenoids were very sensitive to detergent stress and significantly reduced at detergent concentration above 1 or 10 mg L-1. Both the detergents caused an increased cell leakage and reduced cell viability, and in most cases, this effect was statistically significant at detergent doses above 10 mg L-1. Exposure to detergents caused an increased accumulation of Na+, K+, and Ca2+ in maize seedlings. It can be concluded that detergents present in irrigation water at higher concentrations can adversely affect maize by impairing light-harvesting pigments and cell viability.

Effects of industrial wastewater on growth and biomass production in commonly grown vegetables.

In developing countries like Pakistan, irrigation of crops with industrial and municipal wastewater is a common practice. However, the impact of wastewater irrigation on vegetables growth has rarely been studied. Therefore, the present study was conducted to determine the effect of industrial wastewater on the germination and seedling growth of some commonly grown vegetables in Pakistan. Wastewater samples were collected from two different industries (marble industry and match alam factory) at Hayatabad Industrial Estate (HIE) in Peshawar, Pakistan, and their effect on different growth parameters of four vegetables including Hibiscus esculentus, Lactuca sativa, Cucumis sativus, and Cucumis melo was investigated. The obtained results revealed that wastewater from marble industry did not affect seed germination except a minor inhibition in H. esculentus. Effluents from match alam factory stimulated seed germination in C. melo and C. sativus but had no effect on seed germination in the other two vegetables. Wastewater increased root and shoot length in H. esculentus, L. sativa and C. melo, but decreased it in C. sativus. Similarly, differential effects of wastewater were observed on fresh and dry biomass of seedlings in all vegetables. It can be concluded that wastewater may have different effects on different crops, depending upon the nature of wastewater and sensitivity of a plant species to wastewater.

Microbial contamination of drinking water in Pakistan--a review.

Water pollution with pathogenic microorganisms is one of the serious threats to human health, particularly in developing countries. The main objective of this article is to highlight microbial contamination of drinking water, the major factors responsible for microbial contamination, and the resulting health problems in Pakistan. Furthermore, this study will be helpful for researchers and administrative agencies to initiate relevant studies and develop new policies to protect further deterioration of water supply with pathogenic microbes and ensure clean and safe drinking water to the public in Pakistan. In Pakistan, water at the source, in the distribution network, and at the consumer tap is heavily polluted with coliforms and fecal coliforms all over the country. An overview of more than 7,000 water samples reviewed here reveals that an average of over 71 and 58 % samples in the country was contaminated with total coliforms and fecal coliforms, respectively. Drinking water contamination accounts for 20 to 40 % of all diseases in the country, which causes national income losses of Rs 25-58 billion annually (US$0.25-0.58 billion, approximately 0.6-1.44 % of the country's GDP). Improper disposal of industrial and municipal wastes is the most important factor responsible for water pollution in the country followed by cross-contamination due to old and leaking pipes and lack of water filtration and disinfection facilities. There is an urgent need for emergency steps to stop further deterioration of water quality and improve the existing water quality so as to protect the public from widespread waterborne diseases.