Ross Sadler

Establishing a public health analytical service based on chemical methods for detecting and quantifying Pacific ciguatoxin in fish samples

A referee analysis method for the detection and quantification of Pacific ciguatoxins in fish flesh has recently been established by the public health analytical laboratory for the State of Queensland, Australia. Fifty-six fish samples were analysed, which included 10 fillets purchased as negative controls. P-CTX-1 was identified in 27 samples, and P-CTX-2 and P-CTX-3 were found in 26 of those samples. The range of P-CTX-1 concentrations was 0.04-11.4 microg/kg fish flesh; coefficient of variation from 90 replicate analyses was 7.4%. A liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) method utilising a rapid methanol extraction and clean-up is reliable and reproducible, with the detection limit at 0.03 microg/kg fish flesh. Some matrix effects are evident, with fish oil content a likely signal suppression factor. Species identification of samples by DNA sequence analysis revealed some evidence of fish substitution or inadvertent misidentification, which may have implications for the management and prevention of ciguatera poisoning. Blinded inspection of case notes from suspect ciguatera poisoning cases showed that reporting of ciguatera-related paraesthesias was highly predictable for the presence of ciguatoxins in analysed fish, with 13 of 14 expected cases having consumed fish that contained P-CTX-1 (p<0.001, Fishers Exact Test).

Occupational and environmental hazard assessments for the isolation, purification and toxicity testing of cyanobacterial toxins

Cyanobacteria can produce groups of structurally and functionally unrelated but highly potent toxins. Cyanotoxins are used in multiple research endeavours, either for direct investigation of their toxicologic properties, or as functional analogues for various biochemical and physiological processes. This paper presents occupational safety guidelines and recommendations for personnel working in field, laboratory or industrial settings to produce and use purified cyanotoxins and toxic cyanobacteria, from bulk harvesting of bloom material, mass culture of laboratory isolates, through routine extraction, isolation and purification. Oral, inhalational, dermal and parenteral routes are all potential occupational exposure pathways during the various stages of cyanotoxin production and application. Investigation of toxicologic or pharmacologic properties using in vivo models may present specific risks if radiolabelled cyanotoxins are employed, and the potential for occupational exposure via the dermal route is heightened with the use of organic solvents as vehicles. Inter- and intra-national transport of living cyanobacteria for research purposes risks establishing feral microalgal populations, so disinfection of culture equipment and destruction of cells by autoclaving, incineration and/or chlorination is recommended in order to prevent viable cyanobacteria from escaping research or production facilities.

First Report of a Toxic Nodularia spumigena (Nostocales/ Cyanobacteria) Bloom in Sub-Tropical Australia. I. Phycological and Public Health Investigations

Cyanobacterial blooms represent one of the most conspicuous and widespread waterborne microbial hazards to human and ecosystem health. Investigation of a cyanobacterial bloom in a shallow brackish water recreational cable ski lake in south-eastern Queensland, Australia revealed the dominance of the toxigenic species Nodularia spumigena. The bloom spanned three months, during which time cell concentrations exceeded human guideline thresholds for recreational risk, and concentrations of the hepatotoxic cyanotoxin nodularin exceeded 200 µg L−1. Cyanotoxin origin and identification was confirmed by amplification of the ndaF-specific PCR product and sequencing of the 16S rRNA gene. From the limited data available leading up to, and throughout the bloom, it was not possible to establish the set of causative factors responsible for its occurrence. However a combination of factors including salinity, hydraulic retention time and nutrient status associated with an extended period of drought are likely to have contributed. This was the first known occurrence of this species in bloom proportions from sub-tropical Australia and as such represents a hitherto uncharacterized risk to human and ecosystem health. It highlights the need for adaptive monitoring regimes to ensure a comprehensive understanding of the potentially toxic cyanobacteria likely to inhabit any given region. Such monitoring needs to recognize that cyanobacteria have a significant capacity for range expansion that has been facilitated by recent changes in global climate.

Bioavailability study of arsenic and mercury in traditional Chinese medicines (TCM) using an animal model after a single dose exposure

Traditional Chinese medicines (TCM) are increasingly being used as alternative medicines in many countries, and this has caused concern because of adverse health effects from toxic metal bioavailability such as mercury (Hg) and arsenic (As). The aim of this study was to investigate the bioavailability of As and Hg from TCM after a single exposure dose using an animal model of female Sprague-Dawley rats. The rats were divided into 6 groups which included four groups treated with sodium arsenite (NaAsO2), arsenic sulfide (As2S3), mercuric chloride (HgCl2), mercuric sulfide (HgS), and two groups treated with TCM containing high Hg or As (Liu Shen Wan: As 7.7-9.1% and Hg 1.4-5.0%; Niuhang Jie du Pian: As 6.2-7.9% and Hg <0.001%). The samples of urine, faeces, kidney and liver were collected for analysis and histological assay. The results indicated that relatively low levels of As and Hg from these TCM were retained in liver and kidney tissues. The levels of As in these tissues after TCM treatment were consistent with the levels from the As sulphide treated group. With the exception of the mercuric chloride treated group, the levels of Hg in urine from other groups were very low, and high levels of As and Hg from TCM were excreted in faeces. The study showed poor bioavailability of As and Hg from TCM as indicated by low relative bioavailability of As (0.60-1.10%) and Hg (<0.001%). Histopathological examination of rat kidney and liver tissues did not show toxic effects from TCM.

Quantifying accessibility and use of improved sanitation: towards a comprehensive indicator of the need for sanitation interventions

To prevent diseases associated with inadequate sanitation and poor hygiene, people needing latrines and behavioural interventions must be identified. We compared two indicators that could be used to identify those people. Indicator 1 of household latrine coverage was a simple Yes/No response to the question “Does your household have a latrine?” Indicator 2 was more comprehensive, combining questions about defecation behaviour with observations of latrine conditions. Using a standardized procedure and questionnaire, trained research assistants collected data from 6,599 residents of 16 rural villages in Indonesia. Indicator 1 identified 30.3% as not having a household latrine, while Indicator 2 identified 56.0% as using unimproved sanitation. Indicator 2 thus identified an additional 1,710 people who were missed by Indicator 1. Those 1,710 people were of lower socioeconomic status (p < 0.001), and a smaller percentage practiced appropriate hand-washing (p < 0.02). These results show how a good indicator of need for sanitation and hygiene interventions can combine evidences of both access and use, from self-reports and objective observation. Such an indicator can inform decisions about sanitation-related interventions and about scaling deworming programmes up or down. Further, a comprehensive and locally relevant indicator allows improved targeting to those most in need of a hygiene-behaviour intervention.

Household Latrines to Control Environmental Contamination and Helminthiasis: An Exploratory Study in Indonesia

In rural Indonesia, soil-transmitted helminth (STH) infections cause health problems and impair social development. We investigated whether those problems could be solved by the use of household latrines (the ‘BALatrine’). Our method was to study two villages, of which only one had household latrines. The dependent variables were environmental contamination (Escherichia coli in well water), STH-related illnesses and symptoms, and absence from work or school due to bowel infections. The village with latrines had less E. coli contamination. STH-related illnesses and symptoms were less prevalent among participants who had a latrine than among those who did not. Absence from work or school due to bowel infection was much less common among participants who had a latrine than among those who did not (6.2% vs 40.3%). In conclusion, the BALatrine could have important public-health and social benefits, and that hypothesis should be tested in a controlled longitudinal study.

An opinion on the distribution and behavior of chemicals in response to climate change, with particular reference to the Asia-Pacific region

There is a general lack of knowledge as regards the effects of climate change on pollutant behavior. This is particularly true of the Asia-Pacific Region (APR). This region has major significance in terms of global pollutant emission and also displays a wide variety of environments. This review presents the authors’ opinions on possible implications of climate change for pollutant behavior in the APR. Although differing responses can be expected across the region, there are clear implications as regards the short- and long-term behavior of pollutants. Effects can be predicted through modeling, but further data are required for model calibration. Nevertheless, it can be predicted that climate change will affect processes including global distillation of persistent organic pollutants, airborne transport of heavy metals, half-life of readily degradable pollutants, and eutrophication in water bodies. Particulates are expected to play a central role in mediating the effects of climate change, and successful predictive models will need to be based on particulate-mediated transport and behavior. Climate change also has the potential to cause an increase in the intensity and frequency of harmful algal blooms in aquatic environments throughout the region, with significant implications for supply of both food and drinking water.

Consistent chemical form of Cd in liver and kidney tissues in rats dosed with a range of Cd treatments: XAS of intact tissues

X-ray absorption spectroscopy of frozen intact tissues shows that in rats exposed to a range of treatments involving cadmium, alone or in combination with other metal ions, the coordination environment of cadmium is consistent in both the liver and kidney. Comparison of the spectra from the rat tissues to biologically relevant model compounds indicates that the vast majority of the cadmium is bound to metallothionein in these tissues.

Soil transport of wood preservatives applied to the base of power poles

In the past, a variety of persistent organic chemicals (principally aldrin, dieldrin and coal tar), were placed in soil surrounding wooden power poles, in an attempt to control wood rotting organisms. With time, the chemicals have migrated both horizontally and vertically from the region of application, resulting in appreciable levels of these contaminants around power pole bases. The migration of the chemicals appears to be controlled by a number of factors including soil moisture status and solubility of the chemical. Dieldrin and the lower molecular weight PAHs show the greatest mobility. A significant conversion of aldrin to dieldrin was apparent in the upper layers of soil. It was found that the vertical and horizontal migration of the contaminants in soil correlated well with molecular descriptors such as water solubility and first order connectivity index.’

Global Distillation in an Era of Climate Change

When a chemical enters the natural environment it undergoes change by several processes. It can be transported by the movement of the sector of the environment it enters, for example ocean currents and atmospheric movements, to a different geographical location. In addition as it is transported it is usually diluted so that its concentration is reduced. Chemical degradation processes take place which result in the production of more polar and water soluble products and leaving residual initial chemical. As all of these processes occur there is a distribution of the chemical between the phases in the environment. These processes have been described in a series of papers and books by Mackay as reported in Mackay et al (2009). The processes shown in Figure 1 illustrate the basic processes involved in the partitioning of a chemical into phases in the environment. All of the processes shown involve two phases and movement backwards and forwards of the chemical and thus can be characterised by a partition coefficient. The partition coefficient is the ratio of the chemical in the two phases at equilibrium and isoften represented by the symbol, K. Thus the air – water partition coefficient is represented by KAW and is better known as the dimensionless Henrys Law constant (Shiu and Mackay, 1986), the fish – water partition coefficient is KB, (Connell, 1990) the sediment – water coefficient is KD (Gobas and Maclean, 2003) and the other partition processes can be represented in a similar way. It is of interest to note that as a result of these partition processes a chemical can occur in very low concentrations in the atmosphere, low concentration in water but relatively high concentrations in fish and other aquatic biota. Most of these partition coefficients can be calculated from partition values arrived at by laboratory measurements. For example the Henrys Law constant and the octanol – water partition coefficient, KOW , can be measured in the laboratory. The KOW can be used to calculate the fish – water partition coefficient, KB value and also the KD value and is extensively used to model chemical partitions in the environment. The octanol – air partition coefficient, KOA, can be calculated or measured in the laboratory and can be used to evaluate the partitioning of a chemical into organisms as a result of concentrations in the atmosphere. The Persistent Organic Pollutants (POPs) are a group of mainly chlorinated hydrocarbon insecticides and dioxins which are often reported to undergo global distillation (Fernandez and Grimalt, 2003). These substances undergo the partition processes illustrated diagrammatically in Figure 1. However if they are discharged to the environment in the warmer zones of the planet a proportion will partition into the atmospheric phase according to the partition coefficient at that temperature. Movement in the atmosphere through winds