Ian Clark

Maturity indices in co-composting of chicken manure and sawdust with biochar

Several maturity indices were evaluated for in-vessel co-composting of chicken manure and pine sawdust with three different biochars. All the seven mixtures (piles) contained chicken manure and sawdust. Six of these piles contained biochar; each biochar was added at two rates, 5% and 10% wet weight. The maturity of composts was assessed by C/N, dissolved organic carbon (DOC), seed germination, NO3(-)-N/NH4(+)-N, and the Solvita test. The C/N values of finished composts were from 31.5 to 35.7, which were much higher than the optimum value of 21 for matured compost. Nevertheless, the rest of the parameters indicated that the composts were matured. The C/N values were high because of the high amount of recalcitrant carbon present in the feedstocks: biochar and sawdust. Biochar treated piles showed higher respiration as well as decomposition of DOC indicating higher microbial activity. Use of biochar in composting may reduce NH3 emission and nitrate leaching.

The Role of Bioretention Systems in the Treatment of Stormwater

Abstract Urbanization leads to water catchments becoming more impervious and channelized. These modifications to the natural landscape result in reduced water infiltration into soils and base flow components that cause a greater volume and rate of surface water runoff. In contrast to conventional stormwater management systems, water-sensitive urban design (WSUD) technologies manage rainfall where it falls, through enhancement of infiltration capacity of impervious areas and rerouting runoff across pervious areas. WSUD aims to better incorporate several urban water sources, including stormwater, into the local hydrological cycle so as to (1) reduce demand on potable water, (2) minimize pollutant loading to surface waters, and (3) restore or maintain predevelopment hydrological processes. Bioretention systems are designed to remove both dissolved pollutants and particulate matter from stormwater runoff and reduce the volume and rate of stormwater discharged. Treatment is achieved via a number of chemical, biological and physical processes including sedimentation, filtration, sorption, reduction, vegetative uptake and microbial biomass assimilation. The efficiency of bioretention systems in the treatment of contaminants in stormwater depends on a number of factors including substrate conditions, type of vegetation, climatic conditions and on the volume and rate of stormwater infiltrated and discharged. This chapter discusses the various processes involved in the treatment of stormwater within bioretention systems; in particular, the fate of nutrients such as nitrogen and phosphorus, and metals, and the soil–plant processes involved in their retention. The factors affecting treatment efficiency are also examined.

Speciation and bioavailability of lead in complementary medicines.

Complementary medicines have associated risks which include toxic heavy metal(loid) and pesticide contamination. The objective of this study was to examine the speciation and bioavailability of lead (Pb) in selected complementary medicines. Six herbal and six ayurvedic medicines were analysed for: (i) total heavy metal(loid) contents including arsenic (As), cadmium (Cd), Pb and mercury (Hg); (ii) speciation of Pb using sequential fractionation and extended x-ray absorption fine structure (EXAFS) techniques; and (iii) bioavailability of Pb using a physiologically-based in vitro extraction test (PBET). The daily intake of Pb through the uptake of these medicines was compared with the safety guidelines for Pb. The results indicated that generally ayurvedic medicines contained higher levels of heavy metal(loid)s than herbal medicines with the amount of Pb much higher than the other metal(loid)s. Sequential fractionation indicated that while organic-bound Pb species dominated the herbal medicines, inorganic-bound Pb species dominated the ayurvedic medicines. EXAFS data indicated the presence of various Pb species in ayurvedic medicines. This implies that Pb is derived from plant uptake and inorganic mineral input in herbal and ayurvedic medicines, respectively. Bioavailability of Pb was higher in ayurvedic than herbal medicines, indicating that Pb added as a mineral therapeutic input is more bioavailable than that derived from plant uptake. There was a positive relationship between soluble Pb fraction and bioavailability indicating that solubility is an important factor controlling bioavailability. The daily intake values for Pb as estimated by total and bioavailable metal(loid) contents are likely to exceed the safe threshold level in certain ayurvedic medicines. This research demonstrated that Pb toxicity is likely to result from the regular intake of these medicines which requires further investigation.

Grid Sketching to Aid Teaching Geological Mapping in an Area of Complex Polydeformation

Fieldwork is a vital element in general undergraduate geological education. Our method introduces field mapping at an early stage by using a simple technique of scaled sketching to teach fundamental mapping and geological principles. Using fully exposed shore-platform outcrops of highly metamorphosed and polydeformed Proterozoic gneisses from Corny Point in South Australia, we have designed a simple exercise to get students to progressively transfer information about one-metre-square areas of rock platform, defined by a chalk grid, onto graph paper to quickly produce a geological map. Students are readily motivated and learn critical skills rapidly under close supervision and using detailed instructions. Discussions with instructors and peers on site aid personal and group improvement in mapping techniques commonly perceived as difficult to master. Evaluation of student understanding and progress has shown the method to be effective, economical, and, most importantly, enjoyable.

Groundwater flow and geochemical evolution in the Central Flinders Ranges, South Australia

The chemical characteristics of water in the Oratunga Area, Central Flinders Ranges, South Australia have been used to evaluate and determine the processes controlling water chemistry in addition to the sources of ions. The isotopic analysis results show that the groundwater is mainly meteoric. Based on the rock and water chemistry, ionic ratios, hydrochemical facies and saturation indices, the chemical evolution has been studied. The chemistry of groundwater revealed two types of water. Thus, in high topographic areas, low TDS, bicarbonate and mixed water types are dominated and support a rapid and direct recharge. While in the low topographic areas, high TDS and chloride compositions are the most common attributed to the accumulation of ions and groundwater evolution. Analysis of the ion concentration, head data and saturation indices shows a compositional trend that can be studied as an evolutionary system. The ionic ratios and hydrogeochemical modelling using NETPATH was used to quantify and verify the different hydrochemical processes. The resulting data shows that calcite dissolution/precipitation and cation exchange reactions are the major processes affecting groundwater chemical evolution of the groundwater in the basin. This study has provided a basis for a better understanding of the hydrogeologic setting in areas of a little data.

Development, Implementation and Evaluation of a Standards-Based Earth Systems Education Course for Middle School Teachers

An Earth System Science (ESS) framework was used to integrate Earth, life and physical science topics in the development of a series of courses for in-service and pre-service middle school science teachers in South Carolina. The first of these courses was an integrated, thematic, standards- and inquiry-based course was pilot-tested with a group of practicing middle school science teachers and was found to be effective in terms of increasing knowledge of Earth System Science, influencing teachers to employ inquiry-based instructional strategies in their classrooms more often than before the start of the course, and influencing teachers to be more likely to employ authentic assessment strategies in their classrooms. These outcomes demonstrate that it is possible to employ modern pedagogical practices effectively in an ESS framework. The use of this course model could be implemented widely in both pre- and in-service science courses for Earth Science teachers.

GeologiCAL structure — Multimedia presentation and modelling software

Abstract We have developed Computer Aided Learning (CAL) courseware for use in undergraduate structural geology subjects. The courseware covers the whole structural curriculum, is based on presen-tation and other interactive multimedia software, and is integrated throughout the lectures, laboratory classes, workshops, and even within the fieldwork programme. With the progressive establishment of a digital teaching and learning environment equipped with fully networked personal computers, mass storage devices, computer projec-tion, and computer suites, we have now developed and exclusively use a fully integrated electronic classroom for our structure courses.