The iodinated X-ray contrast media are the most widely administered intravascular pharmaceuticals and are known to persist in the aquatic environment. A rapid method using direct injection liquid chromatography-tandem mass spectrometry (DI-LC-MS/MS) has been developed to measure eight ICM. These include iopamidol, iothalamic acid, diatrizoic acid, iohexol, iomeprol, iopromide, plus both ioxaglic acid and iodipamide, which have not previously reported in the literature. The LC-MS/MS fragmentation patterns obtained for each of the compounds are discussed and the fragments lost for each transition are identified. Matrix effects in post-RO water, MQ water, tap water and secondary effluent have also been investigated. The DI-LC-MS/MS method was validated on both secondary and tertiary treated wastewater, and applied to samples from an advanced activated sludge wastewater treatment plant (WWTP) and a water recycling facility using microfiltration (MF) and reverse osmosis (RO) in Perth, Western Australia. As well as providing information of the efficacy for RO to remove specific ICM, these results also represent the first values of ICM published in the literature for Australia.

A suite of 34 disinfection by-products (DBPs), including 8 halomethanes, 9 haloacetic acids, 6 haloacetonitriles, 6 haloaldehydes, 4 haloketones and the halonitromethane chloropicrin, were monitored in two microfiltration (MF) and reverse osmosis (RO) treatment plants as part of a larger study of chemical removal by MF/RO treatment for water recycling purposes. Both DBP detection frequency and concentration increased during treatment, and this was attributed to a chloramination step used to minimize RO membrane fouling. The degree of DBP formation was particularly related to plant residence time, with DBPs falling into two distinct groups; the first group in which DBP concentration increased with increasing residence time (e.g. chloroform and bromochloroacetaldehyde) and a second group in which increased residence time did not affect the concentration (e.g. dichloroacetic acid and 1,1-dichloropropanone). These results indicate that MF/RO plant design and wastewater quality are both important factors in minimising DBP formation within MF/RO treatment. RO rejection was influenced by several chemical-specific properties, including pKa, log Kow and DBP class. Rejection of haloacetic acids, present as charged molecules, was consistently better than 90% and did not alter with log Kow. For all other DBPs, present as neutral molecules, rejection was much more variable, and decreased with decreasing log Kow, although the effect of MW and log Kow on rejection could not be separated. The DBP formation described in this study lead to variable estimations of DBP removal by RO and thus it is recommended that DBPs are used as indicators of RO removal efficiency with caution, and only after DBP formation within RO treatment has been studied.

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A “plastic” or “chemical” taint, has recently emerged as a problem in drinking water in Perth, Western Australia. The taste occurs intermittently in zones receiving blends of treated groundwaters from several sources, generally only in boiled water. The compound primarily responsible is 2,6-dibromophenol (taste threshold concentration 0.5 ng/L). It was established that the relative ratios of phenol, bromide and chlorine, and pH are important determinants in whether the taste would or would not form and that the primary sources of phenol are plastic appliances, especially kettles and refrigerators (Heitz et al., 2001). However, bromophenol formation varied widely between waters from different sources, even though reaction conditions were ostensibly identical, and it was concluded that another, as yet unknown, factor must influence the reaction rate. This could account for observations that plastic taste only occurred in some groundwaters, but not in others. In the present study the effects of organic and inorganic nitrogen-containing compounds on phenol bromination rates were examined, with the view that this might give some insights into the nature of the unknown factor discussed above. These compounds slowed the rate of bromophenol formation, and results suggested that disinfection using chloramine, rather than chlorine, could prevent plastic taste problems.

For a living cell to stay vital, it must transport molecules and organelles to their designated positions within the cell. Similar to motorized interstate transport systems, cells achieve their transport using motor proteins. One fascinating motor protein, kinesin, hauls its cargo on microtubule tracks at a speed of 2 μm/sec, a process fueled by ATP hydrolysis. The structure of kinesin consists of two heads (motors) each with an ATP binding pocket and a microtubule‐binding domain that spans the length of its motor subunit. The two motors are attached to the neck domain, which consists of a neck linker and a neck coil. As it begins its journey, kinesin docks one motor head at a time to a microtubule unit. ATP binds to the docked head (the leading head) and undergoes hydrolysis, causing a power stroke. Detailed studies showed that this sequence of events leads to a kinesin's hand‐over‐hand moving pattern. Other structural elements in kinesin include a coiled‐coil stalk with hinge regions that allow kinesin to fold on itself, an energy saving process adopted when the protein is idle, a tail domain and a light chain subunit that contain cargo binding sites. Mutated kinesin has been linked to multiple diseases including, Alzheimer's, neurofibromatosis, Huntington's disease and cancer. The Pittsburg High School SMART TEAM used 3D technology to design a model of kinesin's motor and neck domains to better understand their structure‐function link. This knowledge may shed light on how mutations in these regions can lead to diseases linked to kinesin's role in cellular transport.