The use of coagulant and natural soil to control cyanobacterial blooms in a tropical reservoir.

Cyanobacterial blooms have been a growing problem in water bodies and attracted attention from researcher and water companies worldwide. Different treatment methods have been researched and applied either inside water treatment plants or directly into reservoirs. We tested a combination of coagulants, polyaluminium chloride (PAC) and iron(III) chloride (FeCl3), and ballasts, luvisol (LUV) and planosol (PLAN), known as the 'Floc and Sink' technique, to remove positively buoyant cyanobacteria from a tropical reservoir water. Response Surface Methodology (RSM) based on Central Composite Design (CCD) was used to optimize the two reaction variables - coagulant dosage (x1) and ballast dosage (x2) to remove the response variables: chlorophyll-a, turbidity, true color, and organic matter. Results showed that the combination of LUV with PAC effectively reduced the concentration of the response variables, while PLAN was ineffective in removing cyanobacteria when combined to PAC or FeCl3. Furthermore, FeCl3 presented poorer floc formation and lower removal efficiency compared to PAC. This study may contribute to the theoretical and practical knowledge of the algal biomass removal for mitigating eutrophication trough different dosages of coagulants and ballasts.

Understanding the properties of activated carbon and biochar for the adsorption and removal of cyanotoxins: a systematic review.

Cyanotoxins pose a health threat when present in the drinking water supply since conventional water treatment processes are not effective in removing extracellular metabolites hence, advanced treatment techniques are usually applied. Powdered activated carbon (PAC) is an effective adsorbent for removing toxins. However, since a high volume is necessary, alternative adsorbents have been investigated. Biochar, especially from renewable sources, is a potential adsorbent material that could replace PAC for removing toxins. This paper aimed to investigate which PAC properties play key roles in cyanotoxin adsorption by a systematic review addressing the adsorption of toxins such as microcystins-LR (MC-LR), cylindrospermopsin (CYL), and saxitoxins (STXs). As a result, the review showed that some commonly adopted indices (i.e. total surface area) are not relevant to cyanotoxin adsorption, especially if appraised alone. Along with a multi-barrier approach, PAC has to be applied taking into account the complexity of the water system, which includes a better understanding of the characteristics of the adsorbent, the target toxin, and the aqueous medium. The biochar systematic review showed that no studies have yet been designed specifically for the removal of toxins. Since biochar has not yet been applied to water treatment processes, the knowledge gap is even greater than for PAC.

Exantema laterotorácico unilateral con evolución atípica / Unilateral laryngeal eruption with atypical evolution

Una niña lactante presentó un exantema maculo-papular pruriginoso unilateral con evolución uni y contralateral. Aparentemente, el exantema fue desencadenado por una infección viral del tracto respiratorio.Los términos con que se ha descrito esta dermatosis son:exantema latero-torácico unilateral, exantema periflexural asimétricoy más recientemente exantema superpuesto lateralizado de la infancia. Este exantema es deevolución benigna yautolimitada,se presentacomúnmente como un exantema escarlatiniforme o morbiliforme que generalmente se inicia en la axila y después se disemina al tronco y miembro superior homolateral. El tratamiento es sintomático.

A female infant presented with pruritic unilateral macular rash with bilateral evolution. Apparently, the rash was triggered by a viral respiratory tract infection. Unilateral laterothoracicexanthem, asymmetric periflexural exanthema and more recently superimposed lateralized exanthem of childhoodare terms used to define this rash. It has self-limiting evolution. Commonly presented as a scarlatiniform or morbilliformrash that usually begins in the axilla and then spreads to the trunk and homolateralupper limbs. The treatment is symptomatic.