National Research Centre for Environmental Toxicology Publications - UQ eSpace

A bloom of Lyngbya majuscula in Shoalwater Bay, Queensland, Australia: An important feeding ground for the green turtle (Chelonia mydas)

2007-08-15T00:00:00Z

Lyngbya majuscula, a toxic cyanobacterium, was observed blooming during June-July (winter) 2002 in Shoalwater Bay, Queensland, Australia, an important feeding area for a large population of green turtles (Chelonia mydas). The bloom was mapped and extensive mats of L majuscula were observed overgrowing seagrass beds along at least 18 km of coast, and covering a surface area of more than I I km(2). Higher than average rainfall preceded the bloom and high water temperatures in the preceding summer may have contributed to the bloom. In bloom samples, lyngbyatoxin A (LA) was found to be present in low concentration (26 mu g kg(-1) (dry weight)), but debromoaplysiatoxin (DAT) was not detected. The diet of 46 green turtles was assessed during the bloom and L. majuscula was found in 51% of the samples, however, overall it contributed only 2% of the animals' diets. L. majuscula contribution to turtle diet was found to increase as the availability of the cyanobacterium increased. The bloom appeared to have no immediate impact on turtle body condition, however, the presence of a greater proportion of damaged seagrass leaves in diet in conjunction with decreases in plasma concentrations of sodium and glucose could suggest that the turtles may have been exposed to a Substandard diet as a result of the bloom. This is the first confirmed report of L. majuscula blooming in winter in Shoalwater Bay, Queensland, Australia and demonstrates that turtles consume the toxic cyanobacterium in the wild, and that they are potentially exposed to tumour promoting compounds produced by this organism. (c) 2005 Elsevier B.V. All rights reserved.

Absence of p53 mutations in mammary gland preneoplastic and adenocarcinomas tissues of rats exposed to activated ptaquiloside

2008-06-06T00:00:00Z

Access to drinking-water and arsenicosis in Bangladesh

2007-10-17T00:00:00Z

The discovery of arsenic contamination in groundwater has challenged efforts to provide safe drinking-water to households in rural Bangladesh. Two nationally-representative surveys in 2000 and 2002 investigated water-usage patterns, water-testing, knowledge of arsenic poisoning, and behavioural responses to arsenic contamination. Knowledge of arsenicosis rose between the two surveys among women from 42% to 64% but awareness of consequences of arsenic remained limited; only 13% knew that it could lead to death. Behavioural responses to arsenic have been limited, probably in part because of the lack of concern but also because households are uncertain of how best to respond and have a strong preference for tubewell water even when wells are known to be contaminated. Further work conducted by the survey team highlighted the difficulties in providing alternative sources of water, with many households switching back to their original sources of water.

Accumulation and toxicity of monophenyl arsenicals in rat endothelial cells

2007-08-15T00:00:00Z

Clark 1 (diphenylarsine chloride) and Clark 2 ( diphenylarsine cyanide) were used as chemical weapon agents (CWA), and the soil contamination by these CWA and their degraded products, diphenyl and phenyl arsenicals, has been one of the most serious environmental issues. In a series of comparisons in toxicity between trivalent and pentavalent arsenicals we investigated differences in the accumulation and toxicity of phenylarsine oxide (PAO(3+)) and phenylarsonic acid (PAA(5+)) in rat heart microvascular endothelial cells. Both the cellular association and toxicity of PAO(3+) were much higher than those of PAA(5+), and LC50 values of PAO(3+) and PAA(5+) were calculated to be 0.295 muM and 1.93 mM, respectively. Buthionine sulfoximine, a glutathione depleter, enhanced the cytotoxicity of both PAO(3+) and PAA(5+). N-Acetyl-L-cysteine (NAC) reduced the cytotoxicity and induction of heme oxygenase-1 (HO-1) mRNA in PAO(3+)-exposed cells, while NAC affected neither the cytotoxicity nor the HO-1 mRNA level in PAA(5+)-exposed cells. The effect of NAC may be due to a strong affinity of PAO(3+) to thiol groups because both NAC and GSH inhibited the cellular accumulation of PAO(3+), but PAA(3+) increased tyrosine phosphorylation levels of cellular proteins. These results indicate that the inhibition of protein phosphatases as well as the high affinity to cellular components may confer PAO(3+) the high toxicity.

A cleaner river: Long term use of semipermeable membrane devices demonstrate that concentrations of selected organochlorines and PAHs in the Brisbane River estuary, Queensland have reduced substantially over the past decade

2011-09-18T00:06:57Z

We first used semipermeable membrane devices as samplers to evaluate concentrations of organochlorines and PAHs in the Brisbane River in 1998. Here we revisit this work and repeat the study a decade later in the same season (summer), also taking account of results from a similar study involving PAHs in the summer of 2001–2002. The accumulation of organochlorines and most PAHs in the samplers in the recent assessment was substantially less than in the 1998 deployment, suggesting that the ambient concentrations of these chemicals have decreased considerably over the last decade. In all cases there was high reproducibility of the mass of chemicals accumulated in the sampler. We used performance reference compounds in the later deployment, and assuming that the kinetics were similar in both deployment periods, we estimate that the concentration of dieldrin, the organochlorine found at highest concentrations, decreased from approximately 3.9 ng/L to about 1.4 ng/L. The decrease of most other analytes of interest including DDE and DDD was greater, potentially indicating that dieldrin is still entering the Brisbane River through run-off from urban areas where it was used widely for treatment of termites until 1995. DDT use in Australia ceased in the mid 1980s.

A commentary on the impacts of metals and metalloids in the environment upon the metabolism of drugs and chemicals

Moore, Michael R. — 2007-08-15T00:00:00Z

The salient feature of metals is that unlike organic compounds they do not degrade in the environment and barely move from one environmental matrix to another. Human interventions take these compounds from their stable and non-bioavailable geological matrix into situations of biological accessibility. Studies in the 1970s and the 1980s of metal bioavailability and impacts of metals and metalloids were driven by the process of abatement of lead in the environment. Humans have clear and identifiable sources of exposure from fuels, food and leaded water pipes to lead. Interventions started at that time have dramatically lowered human lead exposure. Attention has now shifted to other metals, in particular, cadmium, which has seen increasing use. It is generally accepted that food crops grown on cadmium containing soils or soils naturally rich in this metal are the major source of exposure to humans other than exposure from smoking of cigarettes. This mini-review gives a summary and commentary on early studies on effects of lead on haem metabolism that provide us the clue to why investigations of the impacts of other toxic heavy metals and metalloids such as cadmium and arsenic on different human cytochrome P450 forms have become of great interest at the current time. (C) 2003 Elsevier Ireland Ltd. All rights reserved.

A comparative evaluation of the phytotoxicity of Thames estuary and Brisbane river surface waters

Bengtson Nash, S. M. og Mueller, J. F. — 2009-01-12T00:00:00Z

A Comparison of Potential Soil Movement Characteristics of Various Bifenthrin Formulations on Sandy Loam Soil Report 5 - December 2005

Hasthorpe, A. og Noller, B. N. — 2007-08-14T00:00:00Z

A controlled feeding trial to evaluate the potential for arsenic accumulation in beef cattle

Bruce, S. L. og Noller, B. N. og Ng, J. C. — 2007-08-24T00:00:00Z

A critical review of the effects of gold cyanide-bearing tailings solutions on wildlife

2008-04-28T11:33:29Z

Wildlife deaths associated with cyanide-bearing mine waste solutions have plagued the gold mining industries for many years, yet there is little published data showing the relationship between wildlife mortality and cyanide toxicity. A gap of knowledge exists in monitoring, understanding the causal relationships and managing risks to wildlife from cyanide-bearing waste solutions and tailings. There is a need for the gold industry to address this issue and to meet the International Cyanide Management Code (ICMC) guidelines. The perceived extent of the issue varies, with one study finding the issue inadequately monitored and wildlife deaths grossly underestimated. In Nevada, USA during 1990 and 1991, 9512 carcasses were reported of over 100 species, although there was underestimation due to reporting being voluntary. Of these, birds comprised 80–91% of vertebrate carcasses reported annually. At Northparkes, Australia in 1995, it was initially estimated that 100 bird carcasses were present by mine staff following a tailings incident; when a thorough count was conducted, 1583 bird carcasses were recorded. Eventually, 2700 bird deaths were documented over a four-month period. It is identified that avian deaths are usually undetected and significantly underestimated, leading to a perception that a risk does not exist. Few guidelines and information are available to manage the risks of cyanide to wildlife, although detoxification, habitat modification and denying wildlife access have been used effectively. Hazing techniques have proven ineffective. Apparently no literature exists that documents accurate wildlife monitoring protocols on potentially toxic cyanide-bearing mine waste solutions or any understanding on the analysis of any derived dataset. This places the onus on mining operations to document that no risk to wildlife exists. Cyanide-bearing tailings storage facilities are environmental control structures to contain tailings, a standard practice in the mining industry. Cyanide concentrations below 50 mg/L weak-acid-dissociable (WAD) are deemed safe to wildlife but are considered an interim benchmark for discharge into tailings storage facilities (TSFs). Cyanide is a fast acting poison, and its toxicity is related to the types of cyanide complexes that are present. Cyanide in biota binds to iron, copper and sulfur-containing enzymes and proteins required for oxygen transportation to cells. The accurate determination of cyanide concentrations in the field is difficult to achieve due to sampling techniques and analytical error associated with loss and interferences following collection. The main WAD cyanide complexes in gold mine tailings are stable in the TSF environment but can release cyanide ions under varying environmental conditions including ingestion and absorption by wildlife. Therefore distinction between free, WAD and total cyanide forms in tailings water for regulatory purposes is justified. From an environmental perspective, there is a distinction between ore bodies on the basis of their copper content. For example, wildlife deaths are more likely to occur at mines possessing copper–gold ores due to the formation of copper–cyanide complexes which is toxic to birds and bats. The formation of copper–cyanide complex occurs preferentially to gold cyanide complex indicating the relative importance of economic vs. environmental considerations in the tailings water. Management of cyanide to a perceived threshold has inherent risks since cyanide has a steep toxicity response curve; is difficult to accurately measure in the field; and is likely to vary due to variable copper content of ore bodies and ore blending. Consequently, wildlife interaction needs to be limited to further reduce the risks. A gap in knowledge exists to design or manage cyanide-bearing mine waste solutions to render such facilities unattractive to at-risk wildlife species. This gap may be overcome by understanding the wildlife behaviour and habitat usage of cyanide-bearing solutions.

A critique of PCA's system to control aflatoxin.

Noller, B. N. — 2007-08-23T00:00:00Z

Activation of aflatoxin B1 by mouse CYP2A enzymes and cytotoxicity in recombinant yeast cells

2009-11-30T00:00:00Z

Activation of misonidazole by rat liver microsomes and purified NADPH-cytochrome c reductase

2009-11-30T15:06:44Z

Activation of thiourea bound through sulfur to pentaammineruthenium(III): Structure and reactivity

2009-11-10T08:45:52Z

Acute cadmium chloride administration induces hepatic and renal CYP2A5 mRNA, protein and activity in the mouse: involvement of transcription factor NRF2

2007-08-15T00:00:00Z

Modulation of the cytochrome P450 (CYP) monooxygenase system by cadmium was investigated in male, adult DBA/2J mice treated with a single dose (16 mumol/kg body weight, i.p.) of cadmium chloride (CdCl2). Total CYP content of liver and kidney microsomes decreased maximally (56% and 85%, respectively) 24 and 18 h, respectively, after CdCl2 treatment. Progressive increases of hepatic coumarin 7-hydroxylase (COH) activity; indicative of CYP2A5 activity, relative to the total CYP content were seen at 8 h (2-fold), 12 h (3-fold), 18 h (12-fold), and 24 h (15-fold). Similar changes were seen in the kidney. Liver and kidney CYP2A5 mRNA levels increased maximally 12 and 4 h after treatment and decreased to almost half 6 h later. In contrast, kidney and liver CYP2A5 protein levels increased maximally at 18 and 24 h. The CYP2A5 mRNA levels in the kidney and liver increased after Cd treatment in Nrf2 +/+ but not in Nrf2 -/- mouse. This study demonstrates that hepatic and kidney CYP2A5 is upregulated by cadmium with a somewhat faster response in the kidney than the liver. The strong upregulation of the CYP2A5 both at mRNA and enzyme activity levels, with a simultaneous decrease in the total CYP concentration suggest an unusual mode of regulation of CYP2A5 in response to cadmium exposure, amongst the CYP enzymes. The observed decrease in the mRNA but not in protein levels after maximal induction may suggest involvement of post-trancriptional mechanisms in the regulation. Upregulation of CYP2A5 by cadmium in the Nrf2 +/+ mice but not in the Nrf2 -/- mice indicates a role for this transcription factor in the regulation. (C) 2003 Elsevier Ireland Ltd. All rights reserved.

Acute cadmium chloride administration induces hepatic and renal cytochrome P450 2A5 in the mouse

2007-08-15T04:49:50Z

Modulation of the cytochrome P450 (CYP) monooxygenase system by cadmium was investigated in male, adult DBA/2J mice treated with a single dose (16 Amol/kg body weight, i.p.) of cadmium chloride (CdCl2) at various time points. The total CYP content of kidney microsomes started to decrease 4 hours earlier than in the liver (P < 0.05), with maximal decreases at 24 hours of 56% and 85% in the liver and kidney, respectively. In contrast, both hepatic and renal coumarin 7-hydroxylase (COH) activity (indicative of CYP2A5 activity) relative to total CYP content started to progressively increase at 8 hours, with renal activity 61 times higher than the hepatic activity. Maximum increases were observed, 15-fold in the liver and 64-fold in the kidney after 24 hours. Liver and kidney CYP2A5 mRNA levels increased maximally 12 and 4 hours after treatment, respectively and decreased to almost half 6 hours later. In contrast, kidney and liver CYP2A5 protein levels increased maximally at 18 and 24 hours. This study demonstrates that hepatic and renal CYP2A5 is upregulated by cadmium with a faster response in the kidney than in the liver. This observation is concordant with the fact that kidney is the target organ for cadmium toxicity. The observed increase in the mRNA but not in protein levels after maximal induction suggests involvement of post-transcriptional mechanisms in the regulation of CYP2A5 expression by cadmium.

Acute CdCl2 administration induces hepatic and renal cytochrome P450 2a5 in the mouse; involvement of transcription factor Nrf2

2010-07-22T00:00:00Z

Acute Effects of Recreational Exposure to Freshwater Cyanobacteria - a Prospective Epidemiology Study

2007-08-23T00:00:00Z

Acute intermittent porphyria: alternative splicing of hydroxymethylbilane synthase mRNA excludes exons 3 and 12

2007-08-13T00:00:00Z

The hydroxymethylbilane synthase (HMBS) mRNAs from 44 control individuals and 30 patients suffering from acute intermittent porphyria (AIP), were screened for length differences by reverse transcriptase polymerase chain reaction (RT-PCR) and any abnormalities were characterized by direct sequencing. Examination of the mRNAs extracted from the peripheral blood lymphocytes of the samples revealed varying degrees of alternative splicing, involving the removal of exons 3 and 12. Approximately 10-50% of the mRNA molecules were affected, despite the absence of genomic splice site mutations or any major deviance from consensus splice sequence values. The preliminary data obtained from this study suggest that this event is a normal occurrence in peripheral blood lymphocytes, and may not be associated with the molecular pathology responsible for AIP. (C) 1998 Academic Press Limited.

Acute intermittent porphyria: the in vitro expression of mutant hydroxymethylbilane synthase

2007-08-13T00:00:00Z

Acute intermittent porphyria (AIP) is an inborn error of haem biosynthesis caused by a variety of mutations in the gene coding for hydroxymethylbilane synthase (HMB-S). The entire coding sequence of this gene, from each of three South African AIP patients, was therefore screened for mutations using chemical cleavage mismatch (CCM) analysis and any changes detected characterized by DNA sequencing. Three single base changes were identified; a G(77) to A in exon 3, a C-346 to T in exon 8 and a G(518) to A in exon 10. These missense mutations, previously reported to be present in other populations, are known to be responsible for the structurally deleterious amino acid replacements R26H, R116W and R173Q, respectively. The in vitro expression of the enzymes containing these mutations and the subsequent measurement of their specific activities revealed a reduction to approximately 4% of normal activity. (C) 1997 Academic Press Limited.

Acute oral toxicity of pectlnotoxin-2 Seco acid and 7 epi-pectl-notoxin-2 Seco acid in mice

2007-08-24T00:00:00Z

Acute phase response in horses: changes in plasma cation concentrations after localised tissue injury

2011-02-09T10:50:04Z

An acute phase reaction was elicited in four horses to which Freund's adjuvant was administered intramuscularly. The localised inflammation was accompanied by changes in the plasma concentrations of copper, iron and zinc. The plasma copper concentration, the plasma ceruloplasmin copper concentration and the ceruloplasmin oxidase activity in the plasma steadily increased to a maximum 24 days after the administration of the adjuvant. At this time, the plasma copper concentration was 2.2 micrograms/ml, a 90 per cent increase over the baseline concentration. The ratio of the concentration of plasma ceruloplasmin copper to plasma copper remained constant, indicating that the non-ceruloplasmin bound copper component of the plasma is also an acute phase reactant in the horse. The plasma zinc and iron concentrations decreased to 59 per cent and 30 per cent of their respective baseline concentrations and the severity of the inflammation appeared to influence the plasma concentrations of each metal. Weak correlations between the plasma fibrinogen concentration and the plasma copper and zinc concentrations of 25 horses with plasma fibrinogen concentrations of 5 g/litre or greater indicated that a single measurement of plasma copper concentration is not useful in the diagnosis of non-specific inflammatory disorders of the horse. However, the results suggest that the plasma copper concentrations in serial samples may be used to monitor the resolution of inflammatory disorders in the horse.

Acute Porphyria - A Toxicogenetic Disease

Moore, M. og Hift, R.J. — 2007-08-24T00:00:00Z

Acute toxicity of (chloro-)catechols and (chloro-)catechol-copper combinations in Escherichia coli corresponds to their membrane toxicity in vitro

2009-11-17T00:00:00Z

Acute toxicity of organic chemicals to Gammarus pulex correlates with sensitivity of Daphnia magna across most modes of action

2012-01-22T00:21:44Z

Acute toxicity of triorganotin compounds: Different specific effects on the energy metabolism and role of pH

2009-11-17T00:00:00Z

Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera

2012-05-21T22:06:51Z

Additive toxicity of herbicide mixtures and comparative sensitivity of tropical benthic microalgae

2010-12-19T00:07:14Z

A decision -making process to manage the impact of mine waste on aminal species following site rehabilitation to ensure ecosystem sustainability

Noller, B N og Bruce, S. L. og Ng, J C — 2007-08-23T00:00:00Z

A decision-making process to manage the impact of mine waste on animal species following site rehabilitation to ensure ecosystem sustainabililty

Noller, B. N. og Bruce, S. L. og Ng, J. C. — 2007-08-23T00:00:00Z

A decision-making tool to minimise environmental and public health risk of pesticide application

2007-08-23T00:00:00Z

A desktop human health risk assessment of Arsenic and Lead in soil at woodcutters mine site

2009-04-08T00:00:00Z

A desktop Human Health Risk Assessment of Arsenic and Lead in Soil at Woodcutters Mine Site

Bruce, S. L. og Ng, J. C. og Noller, B. N. — 2007-08-14T00:00:00Z

A Desktop Risk Assessment of Natural Arsenic Occurrence at Enoggera Barracks - a Defence Housing Authority Site

Ng, J. C. og Moore, M. — 2007-08-14T00:00:00Z

Advantages of toxicokinetic and toxicodynamic modelling in aquatic ecotoxicology and risk assessment

Ashauer, Roman og Escher, Beate I. — 2010-12-05T00:08:26Z

Toxicokinetic-toxicodynamic (TK-TD) models simulate the processes that lead to toxicity at the level of organisms over time. These dynamic simulation models quantify toxicity, but more importantly they also provide a conceptual framework to better understand the causes for variability in different species' sensitivity to the same compound as well as causes for different toxicity of different compounds to the same species. Thus TK-TD models bring advantages for very diverse ecotoxicological questions as they can address two major challenges: the large number of species that are potentially affected and the large number of chemicals of concern. The first important benefit of TK-TD models is the role that they can play to formalize established knowledge about toxicity of compounds, sensitivity of organisms, organism recovery times and carry-over toxicity. The second important aspect of TK-TD models is their ability to simulate temporal aspects of toxicity which makes them excellent extrapolation tools for risk assessment of fluctuating or pulsed exposures to pollutants. We provide a general introduction to the concept of TK-TD modelling for environmental scientists and discuss opportunities as well as current limitations. © 2010 The Royal Society of Chemistry.

Adverse Health Effects of Chronic Exposure to Low-Level Cadmium in Foodstuffs and Cigarette Smoke

Satarug, Soisungwan og Moore, Michael R. — 2007-08-15T00:00:00Z

Cadmium is a cumulative nephrotoxicant that is absorbed into the body from dietary sources and cigarette smoking. The levels of Cd in organs such as liver and kidney cortex increase with age because of the lack of an active biochemical process for its elimination coupled with renal reabsorption. Recent research has provided evidence linking Cd-related kidney dysfunction and decreases in bone mineral density in nonoccupationally exposed populations who showed no signs of nutritional deficiency. This challenges the previous view that the concurrent kidney and bone damage seen in Japanese itai-itai disease patients was the result of Cd toxicity in combination with nutritional deficiencies, notably, of zinc and calcium. Further, such Cd-linked bone and kidney toxicities were observed in people whose dietary Cd intakes were well within the provisional tolerable weekly intake (PTWI) set by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives of 1 mug/kg body weight/day or 70 mug/day. This evidence points to the much-needed revision of the current PTWI for Cd. Also, evidence for the carcinogenic risk of chronic Cd exposure is accumulating and Cd effects on reproductive outcomes have begun to emerge.

A field comparison of ethylene vinyl acetate and low-density polyethylene thin films for equilibrium phase passive air sampling of polycyclic aromatic hydrocarbons

2008-05-02T00:00:00Z

Ethylene vinyl acetate (EVA) and low-density polyethylene (LDPE) were compared as thin film polymer passive air samplers for polycyclic aromatic hydrocarbons (PAHs). These samplers were co-deployed for periods of up to 27 days at an urban field site in Brisbane. Despite demonstrated air side resistance to mass transfer, sampling rate ratios indicate rapid accumulation kinetics for EVA compared with LDPE. Confirming theoretically predicted values, sampler-air partition coefficients were greater for EVA as compared with LDPE. The relatively high capacity of EVA films may be an advantage in terms of sensitivity, when film thickness and hence amounts accumulated at equilibrium, are low. Predictions of times to effective equilibrium were made for a nominal film thickness of 1 μm. These predictions indicate that both types of films would be effective equilibrium phase samplers for predominantly vapour phase PAHs with log octanol-air partition coefficients values of 8.7 (pyrene). Despite comparatively rapid linear stage kinetics for EVA, the predicted times to effective equilibrium for PAHs are less for LDPE. This arises due to the relative magnitude of their respective KSA values. The predicted times to equilibrium (25 °C) for pyrene for example are approximately 94 and 34 days for EVA and LDPE, respectively.

A field study conducted at Kidston Gold Mine, to evaluate the impact of arsenic and zinc from mine tailing to grazing cattle

2007-08-14T00:00:00Z

The grazing trial at Kidston Gold Mine, North Queensland, was aimed specifically to assess the uptake of metals from the tailing and the potential for unacceptable contamination of saleable meat. Further aims included estimating metal dose rates and identifying potential exposure pathways including plant uptake of heavy metals, mine tailings adhered to plants and direct ingestion of mine tailing. It was found that of the 11 metals analysed (As, Zn, Co, Cd, Cr, Sn, Pb, Sb, Hg, Se and Ni) in the animal's liver, muscle and blood during the 8-month trial period, only accumulation of arsenic and zinc occurred. A risk assessment including these two metals was conducted to determine the potential for chronic metal toxicity and long-term contamination, using the estimates of metal dose rate. It was concluded that no toxicity or long-term contamination in cattle was likely at this site. Management procedures were therefore not required at this site; however, the results highlight percent ground cover and standing dry matter (DM) as important factors in decreasing metal exposure from direct ingestion of tailings and dust adhered to plants. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

A field study to evaluate the impact of arsenic and lead from mine tailings to grazing cattle

2009-04-08T00:00:00Z

A field study to evaluate the impact of arsenic and lead from mine tailings to grazing cattle

Bruce, S. L. og Noller, B. N. og Ng, J. C. — 2009-04-08T00:00:00Z

A follow-up study to evaluate health outcome in a Chinese population 16 years after the mitigation of arsenic

Ng, Jack — 2009-04-08T00:00:00Z

A global health problem caused by arsenic from natural sources

2007-08-15T00:00:00Z

Arsenic is a carcinogen to both humans and animals. Arsenicals have been associated with cancers of the skin, lung, and bladder. Clinical manifestations of chronic arsenic poisoning include non-cancer end point of hyper- and hypo-pigmentation, keratosis, hypertension, cardiovascular diseases and diabetes. Epidemiological evidence indicates that arsenic concentration exceeding 50 mug l(-1) in the drinking water is not public health protective. The current WHO recommended guideline value for arsenic in drinking water is 10 mug l(-1), whereas many developing countries are still having a value of 50 mug 1(-1). It has been estimated that tens of millions of people are. at risk exposing to excessive levels of arsenic from both contaminated water and arsenic-bearing coal from natural sources. The global health implication and possible intervention strategies were also discussed in this review article. (C) 2003 Elsevier Ltd. All rights reserved.

A global perspective on cadmium pollution and toxicity in non-occupationally exposed population

2008-01-25T00:00:00Z

Cadmium is a non-essential element that has high rates of soil to plant transference compared with other nonessential elements, and certain plant species accumulate large amounts of cadmium from low cadmium content soils. In this paper, levels of cadmium found in major food groups are highlighted together with cadmium levels found in liver and kidney samples from non-occupationally exposed populations. Data on human kidney cadmium levels identified recently, including the study in our own laboratory, are compared with older studies. Human-tissue cadmium contents showed large variations among individuals, but sources of the variation remain unknown. Exposure levels of 30-50 mug per day have been estimated for adults and these levels have been linked to increased risk of bone fracture, cancer, kidney dysfunction and hypertension. Increased mortality was found among individuals showing signs of cadmium renal toxicity compared with those without such signs, suggesting that renal toxicity may be an early warning of complications, sub-clinical or clinical morbidity. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Agronomic treatments enhance growth and arsenic uptake by Chinese brake fern (Pteris vittata L.)

2013-03-01T12:53:11Z

A human health risk assessment of exposure to the cyanobacterial toxin, cylindrospermopsin in drinking water

Shaw, G. R. — 2008-06-06T00:00:00Z

Algal Analysis: Organisms and Toxins

Shaw, Glendon R. og Smith, Maree L. — 2008-06-06T00:00:00Z

Alleviation of lead poisoning in the brain with aqueous leaf extract of the Thunbergia laurifolia (Linn.)

Tangpong, Jitbanjong og Satarug, Soisungwan — 2010-09-19T00:00:00Z

We used seven groups of 8-week-old male ICR mice, with 6 mice in each group, to test if aqueous leaf extract of the Thai medicinal plant Thunbergia laurifolia Linn. (TL) protects against lead poisoning. We found that co-treatment with aqueous TL leaf extract did not affect levels of lead in blood and brain of mice given lead in drinking water at 1 g/L for 8 weeks. However, co-treatment with aqueous TL leaf extract at 100 mg/kg or 200 mg/kg body weight was found to alleviate adverse effects of lead on learning deficit and memory loss, evaluated with water maze swimming test. Further, increased activity of the cell-death marker enzyme caspase-3 was observed in the brain of mice treated with lead, thereby suggesting that the memory loss could be caused by lead-induced loss of neurons in the brain. Co-treatment with aqueous TL leaf extract at 100 mg/kg or 200 mg/kg body weight was found to restore the levels of caspase-3 activity and maintain total anti-oxidant capacity and anti-oxidant enzymes in the brain. TL leaf extract thus reduced neuronal cell death and memory loss caused by lead uptake in mice, and the anti-oxidant activities of the TL leaf extract might account for these effects.

Altered developmental timing in early life stages of Antarctic krill (Euphausia superba) exposed to p,p '-DDE

2012-01-01T13:48:35Z

Alternative water management for controlling simetryn and thiobencarb runoff from paddy fields

2011-03-09T13:50:10Z

Ambient atmospheric levels of PBDEs across urban and rural centres in Australia determined using polyurethane foam (PUF) passive air sampling

2009-03-14T00:00:00Z