Spatial and temporal distribution of cyanobacteria in Batticaloa Lagoon

The necessity to understand the relationship between cyanobacterial species abundance and water quality variations in coastal lagoons is crucial to develop strategies to prevent further cyanobacterial proliferation. This paper evaluates the relationship between water quality variations on the distribution of cyanobacteria during a 12-month period in Batticaloa Lagoon (Sri Lanka) using Redundancy analysis and Pearson correlations. Drastic variations in pH, temperature, salinity, dissolved oxygen (DO) and total phosphorus (TP) levels were reported, but not turbidity and NO₃⁻. This brackish waterbody is hypereutrophic (TP levels > 0.1 mg/L). The cyanobacterial community contained 13 genera and 22 species. NO₃⁻, TP and turbidity levels positively influenced cyanobacterial abundance during all seasons indicating that nutrient (largely phosphorus) and sediment entry control is highly crucial along with periodic monitoring of cyanobacterial growth.     

Low doses of chlorpyrifos interfere with spermatogenesis of rats through reduction of sex hormones

Use of pesticides results in indirect effects on human health. We aimed to evaluate implications of toxicological effects of subchronic chlorpyrifos exposure on reproductive function in male rats. A total of 48 adult Wistar male rats were separated into four groups (n = 12). Animals were gavaged with 2.5 mg/kg (T1), 5 mg/kg (T2), or 10 mg/kg (T3) body weight of chlorpyrifos (CPF) or distilled water (control) daily for 30 days. Organ weights, epididymal sperm parameters, DNA integrity, sex hormonal (FHS and LH) levels, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), and creatinine concentrations were determined on day 31. Another two sets of (four groups/set; n = 10) animals were orally treated with the same doses of CPF, control animal groups were treated with distilled water only for 30 days, and fertility indices and blood plasma acetylcholine esterase (AchE) were determined on day 31. Exposure to CPF resulted in a significant (p < 0.05) decrease in weights of testis and epididymis. An increase in liver weight resulted in reduced sperm counts and sperm motility and an increase in sperm abnormalities. Significant reduction in serum testosterone (p < 0.01), luteinizing hormone (p < 0.05), and follicular stimulating hormone (p < 0.05) levels was evident in animals treated with the highest dose. A significant decrease in the number of viable implantation sites and pups was observed in female rats mated with the T3 (p < 0.01) and T2 (p < 0.05) males. The ALT, AST, GGT, and creatinine contents were significantly increased (p < 0.05 and p < 0.01, respectively) on CPF exposure. A significant (p < 0.01) reduction in blood plasma AchE enzyme was observed with the highest dose. Our results demonstrated that prolonged exposure of CPF induces spermatogenesis damage, possibly through interference with sex hormones and AchE enzyme resulting in reduction of fertility. Therefore, awareness programs on handling CPF (pesticides) to enhance safety warrant minimization of its hazards.     

Removing ammonium from water and wastewater using cost-effective adsorbents: A review

Ammonium is an important nutrient in primary production; however, high ammonium loads can cause eutrophication of natural waterways, contributing to undesirable changes in water quality and ecosystem structure. While ammonium pollution comes from diffuse agricultural sources, making control difficult, industrial or municipal point sources such as wastewater treatment plants also contribute significantly to overall ammonium pollution. These latter sources can be targeted more readily to control ammonium release into water systems. To assist policy makers and researchers in understanding the diversity of treatment options and the best option for their circumstance, this paper produces a comprehensive review of existing treatment options for ammonium removal with a particular focus on those technologies which offer the highest rates of removal and cost-effectiveness. Ion exchange and adsorption material methods are simple to apply, cost-effective, environmentally friendly technologies which are quite efficient at removing ammonium from treated water. The review presents a list of adsorbents from the literature, their adsorption capacities and other parameters needed for ammonium removal. Further, the preparation of adsorbents with high ammonium removal capacities and new adsorbents is discussed in the context of their relative cost, removal efficiencies, and limitations. Efficient, cost-effective, and environmental friendly adsorbents for the removal of ammonium on a large scale for commercial or water treatment plants are provided. In addition, future perspectives on removing ammonium using adsorbents are presented.