Fate of Benzalkonium Chlorides in Natural Environment and Treatment Processes

Benzalkonium chlorides (BACs) are a type of cationic surfactant and are highly adsorptive to negatively charged surfaces during the wastewater treatment process. They can, therefore, enter the aquatic environment via the suspended organic matter in wastewater effluents, and the terrestrial environment through the application of biosolids as a soil amendment for crop production or by the use of reclaimed wastewater for irrigation. This research investigated the fate of the two most commonly used BACs, benzyl dimethyl dodecyl ammonium chloride (BDDA; C12-alkyl chain) and benzyl dimethyl tetradecyl ammonium chloride (BDTA; C14-alkyl chain), individually and in mixture in various natural and engineered systems. Under laboratory conditions, the following potential fate processes of these BACs were investigated: bacterial biodegradation, adsorption and leaching in various agricultural soils amended with biosolids, and plant uptake. A pure Pseudomonas strain biodegraded BACs, but BDTA was more toxic and inhibited the biodegradation of BDDA. Radiolabelled [U-14C-benzyl] BDDA showed about 85% of the initial concentration mineralized within 300 h. Adsorption studies of BACs to agricultural soils showed, BDTA adsorbed more on soil compared to BDDA. Organic carbon normalized adsorption coefficients (Log Koc, L kg–1) for BACs in the soils were \u3e4, which suggested that BACs tend to retain on the organic fraction of soils. Soil column experiments indicated very low leaching (–1 BACs inhibited plant growth to 50% and BACs were found in the root and shoot tissues of both garden cress (Lepidium sativum) and lettuce (Lactuca sativa). An advanced oxidation process (AOP) based on O3/H2O2 showed that about 1.28 g h–1 O3 and 200 mg L–1 of H2O2 at pH 11 degraded 90% of the initial BACs within 30 min. The AOP treated water was not toxic to two species of algae (Chlorella vulgaris and Chlamydomonas reinhardtii); growth rate was about 0.38 d-1 for treated and control samples compared to 0.01 d-1 for samples contained BACs without AOP. About 25 transformation products were identified in the AOP processes following six different degradation pathways

Improvement of Total Sulphur Measurement Techniques for Management of Reactive Mine Tailings

A sample preparation method for total sulphur measurement in reactive mine tailings was developed by ultrasound assisted digestion (USAD) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) technique. KZK-1, asericite schist, was selected as the certified reference material (CRM) and Musselwhite gold mine tailings were used as tailings sample. Experimental factors (i.e. digestion time, temperature and acid-oxidant combination) were studied in two steps. In the first step, a two-level and three-factor (23) full factorial design of experiment was applied and the total sulphur was measured by USAD and ICP-OES technique. The best result at 95% confidence level (P\u3c 0.05) was identified to be 20 minutes of digestion, 80OC and 1ml HNO3:1ml HCl, which can achieve 100% recovery of total sulphur for the selected CRM. Subsequently, the USAD method was compared with other total sulphur measurement techniques (i.e. hot plate assisted digestion method, X-ray fluorescence and LECO-CNS). The investigated method was verified by X-ray diffraction analysis. In the second step, for further improvement, the role of H2O2 (oxidant) was investigated for USAD and ICP-OES technique. The process was optimized by design of experiment and response surface methodology. The optimum result at 95% confidence level (P\u3c 0.05) was identified as 10 minutes of digestion, 77 OC in combination with 1ml HNO3: 1ml HCl : 1.35ml H2O2 for 100% recovery of total sulphur for the selected CRM. The optimum digestion level was applied to tailings and satisfactory result was observed. A regression model equation was developed and verified by the F (Fisher’s) values as well as P (probability) values. The percentage relative standard deviation (%RSD) revealed the precision of the developed technique

Navigating homocolonialism in LGBTQ2+ rights strategies: sexual and political possibilities beyond the current framing of international queer rights

LGBTQ2+ rights have reached a threshold of international attention and promotion and, concurrently, provoked widespread resistance from many governments, intergovernmental organizations (IGOs) and socially conservative and religious movements, both in the Global North and Global South.[1] This process of contention between homophile proponents and homophobic opponents, results in what we call “homocolonialism”: a political process through which LGBTQ2+ human rights are deployed and then resisted as part of both an actual and perceived neo-colonial dynamic (Dellatolla 2020, Rahman 2014; 2020). This dynamic consists on one side of a globalized but yet modular strategy of promoting LGBTQ2+ rights and, on the other, political homophobia consisting of particular forms of social stigma and legal oppression, led by the state but often in alliance with conservative social movements (Bosia and Weiss 2013) and targeted at the full range of non-heterosexualities. Below, we explain the homocolonial dynamic and then suggest pathways to disrupt its negative effects. To illustrate the potential of these disruptions, we focus on a case study of the 156queer movement in Bangladesh, a South Asian Muslim-majority nation that has retained legal homophobia from the British colonial era. We then conclude with a discussion of the implications of such examples for a different approach to queer human rights beyond a focus on “known” sexual identities and the prioritization of legal rights-based strategies

Improvement in Weighting Assignment Process in Analytic Hierarchy Process by Introducing Suggestion Matrix and Likert Scale

Analytic Hierarchy Process (AHP) has been widely used in varieties of decision making processes among several alternatives, where data on pair-wise comparisons are aggregated and the degree of importance of each alternative is quantified. The process of assigning importance or priorities against the alternatives has inherent limitations, which lead to higher possibility of inconsistency. This paper focuses on two basic limitations of the AHP, first one is its inconsistency generated from huge comparisons in judgment matrix and the second one is the use of ranking weightages given by AHP. To eliminate these limitations, this research paper recommends to calculate relative importance among alternatives from the ratings assigned from Likert scale to form a suggestion matrix with zero percent CR before judgment matrix which gives privilege to decision makers to change relative importance within the range of CR. This process intensifies the effectiveness of AHP by reducing time consumption through optimizing inconsistency

Experiences of intersex individuals in Bangladesh: some reflections

No abstract available