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Stress physiology of palm trees II. The effect of heavy metals and high irradiance on the photosynthesis of palm Trachycarpus fortunei
84-88.Views:245A study was carried out to analyse the individual and combined effects of heavy metal toxicity and high irradiance on the photosynthetic characteristics of young, fully expanded leaves of palm seedling Trachycarpus fortunei under laboratory conditions. Heavy metals were found to inhibit both the light and dark reactions of photosynthesis and the inhibition was more affected in the light than in the dark. Single photoinhibitory conditions caused a 60 % decrease in the electron transport activity after 120 min of light exposure which was completely reversible in the dark. In contrast, the combined effect of high light and heavy metal treatment resulted in a 90 % decrease in the activity, but no reversible recovery in the dark could be detected. This indicated that the simultaneous effect of these two stress factors led to irreversible damages of the photosynthetic machinery and as a consequence caused the general destruction of the plant.
Abbreviations and symbols: Fo: initial chlorophyll fluorescence; Fm: maximum total fluorescence; Fv: variable fluorescence; AFi: intermediate level of fluorescence induction; PSII: photosystem 2.
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Effects of wastewater irrigation on soil physico-chemical properties and vegetables quality: A review
7-16.Views:487This study analyses the use of raw urban wastewater for irrigation and its effects on soil characteristics and heavy metal pollution within crops. There is rampant use of urban waste water by small scale urban vegetable farmers in Zimbabwe. This is posing health hazards to the consumers of urban vegetables and decrease in soil functioning. The significance of this study was to appraise the research study related to the use of urban waste water to answer the research question: What is the impact of waste water on selected soil physico-chemical properties and quantities of heavy metals in vegetables irrigated with waste water? A systematic review of 3100 articles from PubMed, Scopus, Web of Science, and Google Scholar (2010–2024) was performed within PRISMA guidelines. After excluding irrelevant studies, 49 from Nigeria, Bangladesh, Iran, Egypt, India, Pakistan, China, Saudi Arabia, and DRC were selected for analysis. These countries were found to have a lot of literature on urban waste water irrigation. This literature review identified an overview of existing literature on urban waste water irrigation and synthesise findings to provide a comprehensive overview of the topic The results showed (P<0.05) soil properties changed significantly: pH (6.0–7.0 to 4.5–5.5), electrical conductivity (0.2–0.4 to 1.5–2.0 dS/m), organic matter (2–3% to 4–6%), cation exchange capacity (10–15 to 20–25 meq/100g) all aligning with the intended outcomes. The level of nutrients (N, P, K) shifted alongside the source of wastewater. Soil also accumulated heavy metals (Zn, Cd, Pb, Fe, Mn, Cu) while the crops accumulated unsafe levels of Pb (2.5 mg/kg), Cd (1.2 mg/kg), and Cr (3.1 mg/kg) which surpassed WHO/FAO limits. The results highlighted the concern for health and environmental hazards. Treatment of the wastewater, monitoring of the soil, and stricter guidelines are needed for safe agricultural practice.
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Hazardous element content and consumption risk of 9 apricot cultivars
61-65.Views:659The heavy metals pollution is one of the problems that arise due to the increased uses of fertilizers and other chemicals to meet the higher demands of food production for human consumption. In order to assess possible health risk of apricot (Prunus armeniaca L.) consumption, levels of Arsenic, Cadmium, Mercury and Lead were determined in fresh and dried samples of "Jumbo cot", "Tom cot", "Gold strike", "Gold bar", "Bergeron", "Bergarouge", "Sweet cot", "Yellow cot" and "Zebra" apricot cultivars. Wet digestion of samples with concentrate HNO3 – H2O2 digester mixture and inductively coupled plasma–atomic emission spectroscopy was used. Highest content of As, Cd, Hg and Pb among all cultivars, were 0.5, 0.04, 1.5 and 0.5mg/kg of dried apricot samples. Fresh fruit samples also contain 0.2, 0.016, 0.6 and 0.2 mg/kg of Arsenic, Cadmium, Mercury and Lead respectively. Daily intake of metals, hazard quotient and health risk index to reveal health risk possibility of dried and fresh fruits consumption were calculate and compared.
