Water quality assessment of streams draining the Akwapim Ridge of Ghana

Surface water samples from seven streams on the Akwapim Ridge were analysed over a period of 1 year for various water quality parameters following standard methods prescribed in APHA, AWWA, WEF and AOAC. The study was carried out in order to assess the suitability of the streams for drinking and other domestic purposes. Additionally, the effect of land use activities was assessed. The study revealed that, generally, most of the physico-chemical parameters of the streams were below the World Health Organization (WHO) limits recommended for drinking water, with the exception of the levels of sulphate and conductivity in three of the streams (Opiafo: 224 mg/1, 908.5 ìS/cm; Kwati: 221.3 mg/1, 920 ìS/cm; and Ademi: 246 mg/1, 1292 ìS/cm), respectively, which were above the WHO requirements. Nevertheless, taking these factors into consideration (except the sulphate and conductivity), the waters may be regarded as excellent and good for drinking and other domestic uses

Advances in research on the use of biochar in soil for remediation: a review

Purpose: Soil contamination mainly from human activities remains a major environmental problem in the contemporary world. Significant work has been undertaken to position biochar as a readily-available material useful for the management of contaminants in various environmental media notably soil. Here, we review the increasing research on the use of biochar in soil for the remediation of some organic and inorganic contaminants.  Materials and methods: Bibliometric analysis was carried out within the past 10 years to determine the increasing trend in research related to biochar in soil for contaminant remediation. Five exemplar contaminants were reviewed in both laboratory and field-based studies. These included two inorganic (i.e., As and Pb) and three organic classes (i.e., sulfamethoxazole, atrazine, and PAHs). The contaminants were selected based on bibliometric data and as representatives of their various contaminant classes. For example, As and Pb are potentially toxic elements (anionic and cationic, respectively), while sulfamethoxazole, atrazine, and PAHs represent antibiotics, herbicides, and hydrocarbons, respectively.  Results and discussion: The interaction between biochar and contaminants in soil is largely driven by biochar precursor material and pyrolysis temperature as well as some characteristics of the contaminants such as octanol-water partition coefficient (KOW) and polarity. The structural and chemical characteristics of biochar in turn determine the major sorption mechanisms and define biochar’s suitability for contaminant sorption. Based on the reviewed literature, a soil treatment plan is suggested to guide the application of biochar in various soil types (paddy soils, brownfield, and mine soils) at different pH levels (4–5.5) and contaminant concentrations ( 50 mg kg−1).  Conclusions: Research on biochar has grown over the years with significant focus on its properties, and how these affect biochar’s ability to immobilize organic and inorganic contaminants in soil. Few of these studies have been field-based. More studies with greater focus on field-based soil remediation are therefore required to fully understand the behavior of biochar under natural circumstances. Other recommendations are made aimed at stimulating future research in areas where significant knowledge gaps exist

Effects of Meaningful Stimuli Contained in Different Numbers of Classes on Equivalence Class Formation

Previous experiments have investigated the function of using pictures or meaningful stimuli on equiv- alence class formation. For example, when attempting to form three 5-member classes (A → B → C → D → E), find- ings have shown that pictures used as C stimuli have increased the probability of producing equivalence class formation relative to when all stimuli in the stimulus set are abstract. The present experiment extends the literature by examining whether the formation of equivalence clas- ses varies as a function of having three (C1, C2, and C3), two (C1 and C2), or one (C1) stimulus as a picture in a set of abstract stimuli. Hence, 60 participants were randomly assigned to 4 different experimental groups: 0-picture group or abstract group (ABS), 1-picture group (1PIC), 2-pictures group (2PIC), and 3-pictures group (3PIC). In addition, we had a reference group with abstract shapes only. The findings from the present experiment showed that 2 of 15 participants in the ABS formed classes. Also, two of 15 participants in the 1PIC formed classes, 8 of 15 participants in the 2PIC formed equivalence clas- ses, and 12 of 15 members in the 3PIC formed classes. The statistical analysis supported the notion that equiva- lence class formation is a function of the number of pic- tures in a potential equivalence class