Effects of substrates containing different concentrations of sewage sludge on physiological parameters and quality of Alibertia edulis (Rubiaceae) seedlings

Toxicity of bisphenol A (BPA) and its analogues BPF and BPS on the free-floating macrophyte Salvinia biloba

Evidence linking the toxicity of bisphenol A (BPA) to environmental and public-health issues has led to restrictions on its use. This compound has been gradually replaced with analogues proposed as a safer alternative, normally bisphenol F (BPF) and bisphenol S (BPS), but these substitutes are structurally almost identical to BPA, suggesting they may pose similar risks. The effects of BPA and these analogues were compared for antioxidant activity, lipid peroxidation, free-radical generation, photosynthetic pigments, and chlorophyll fluorescence in Salvinia biloba Raddi (S. biloba) plants exposed to environmentally relevant and sublethal concentrations (1, 10, 50, 100 and 150 μM). Bisphenol exposure promoted alterations in most of the physiological parameters investigated, with BPS toxicity differing slightly from that of the analogues. Furthermore, S. biloba removed similar levels of BPA and BPF from aqueous solutions with ≈70% removed at the 150 μM concentration, while BPS was less effectively removed, with only 23% removed at 150 μM. These findings show that high concentrations of bisphenols (10≥) are toxic to S. biloba, and even typical environmental levels (≤1 μM) can induce metabolic changes in plants, bringing to light that both BPA and its substitutes BPF and BPS pose risks to aquatic ecosystems.

Germination, cytotoxicity, and mutagenicity in Lactuca sativa L. and Passiflora alata Curtis in response to sewage sludge application

The physical and chemical characteristics of the soil can influence plant growth. When sewage sludge (SS) is applied as a soil fertilizer, the accumulation of non-essential elements contained in it can be toxic for plants. The aim of this study was to understand the effect of SS dosage on the cell cycle of Lactuca sativa L. meristematic cells and on the initial growth of L. sativa and Passiflora alata Curtis. Nine concentrations of SS + distilled water (mg dm-3) corresponding to 0, 20, 40, 60, 80, 120, 160, 320, and 520 t ha-1 were tested in four replicates of 25 seeds. Chemical analysis showed an increase in pH of the sludge from 0 to 80 t ha-1 SS followed by its stabilization thereafter. The highest electrical conductivity was observed at 520 t ha-1 SS. SS negatively affected the germination and initial growth of seedlings from P. alata and L. sativa. Cytogenetic analysis on 6000 L. sativa meristematic cells for each treatment revealed that SS could adversely affect the genetic stability of this species. SS concentrations above 120 t ha-1 adversely affected the germination and early seedling growth of L. sativa and P. alata. At high concentrations (120 t ha-1), SS induced genetic lesions in L. sativa, along with chromosomal and nuclear alterations.

Identification of industrial sewage sludge based on heavy metal profiles: a case study of printing and dyeing industry

The illegal disposal of industrial sewage sludge has caused serious environmental pollution. To develop identification technology of industrial sewage sludge based on the characteristic fingerprints is a promising method that is helpful to clarify the responsibility of illegal enterprises. In this study, heavy metal profiles of sewage sludge from industries (including printing and dyeing industry and other industries) and municipal sewage treatment plant located in eastern China were determined, and their performance of classification was evaluated by principal component analysis (PCA) and linear discrimination analysis (LDA). Results showed that heavy metal composition can be an effective tool for distinguishing sewage sludge between printing and dyeing industry and other industries, with an accuracy rate of 82.9%. Meanwhile, heavy metal speciation may be a promising method for identification of printing and dyeing sludge from municipal sewage sludge, the accuracy rate of which reached 100%. Moreover, antimony (Sb) and zinc (Zn) are two indicators, which can be used to identify sewage sludge between printing and dyeing sub-industries, and the accuracy rate was 90%. We concluded that heavy metal profiles may be a precise and promising tool for identification of printing and dyeing sludge. This study developed a potential method for tracing the source of industrial sewage sludge and establishing the identification database of industrial sewage sludge and provided technical support for the government to supervise the illegal dumping and disposal of industrial sewage sludge.