Camelford water poisoning accident: serial neuropsychological assessments and further observations on bone aluminium

Reducing monitoring costs in industrially contaminated rivers: cluster and regression analysis approach

Monitoring contamination in river water is an expensive procedure, particularly for developing countries where pollution is a significant problem. This study was conducted to provide a pollution monitoring strategy that reduces the cost of laboratory analysis. The new monitoring strategy was designed as a result of cluster and regression analysis on field data collected from an industrially influenced river. Pollution sources in the study site were coal mining, metallurgy, chemical industry, and metropolitan sewage. This river resembles those in other areas of the world, including developing countries where environmental monitoring is financially constrained. Data were collected on variability of contaminant concentrations during four seasons at the same points on tributaries of the river. The variables described in the study are pH, electrical conductivity, inorganic ions, trace elements, and selected organic pollutants. These variables were divided into groups using cluster analysis. These groups were then tested using regression models to identify how the behavior of one variable changes in relation to another. It was found that up to 86.8% of variability of one parameter could be determined by another in the dataset. We adopted 60, 65, and 70% determination levels () for accepting a regression model. As a result, monitoring could be reduced by 15 (60% level) and 10 variables (65 and 70%) out of 43, which comprises 35 and 23% of the monitored variable total. Cost reduction would be most effective if trace elements or organic pollutants were excluded from monitoring because these are the constituents most expensive to analyze.

Spatiotemporal evaluation of water quality incidents in Japan between 1996 and 2007

We present a spatiotemporal evaluation of water quality incidents in Japan considering incident numbers, incident causes, pollutant categories, and pollution effects. Water pollution incidents in first-class river systems almost tripled to about 1487 in the 12 years from 1996 to 2007. In addition, oil makes up the largest proportion of pollutants nationwide (76.61%) and the major source of pollution for each region in Japan. Moreover, every category shows a growth trend, especially since 2005. The main cause of incidents was "Unknown" (43%), followed by "Poor working practice" (24%), and then by "Accident" (10%) and "Other" (10%). In Hokuriku, however, the main cause of incidents was "Poor working practice" (36%), which is greater than "Unknown" (30%). Finally, waterworks (approximately 60%) was the largest of four kinds of water supply infrastructure affected by pollution incidents, followed by simplified waterworks. The population affected by offensive odors and tastes peaked in 1990 and has been decreasing. Overall, the results show the characteristics of incidents from 1996 to 2007, with significant implications for adaptation measures, strategies and policies to reduce water quality incidents.

Effects of acute exposure to aluminum on cognition in humans

There is epidemiological evidence suggesting an association between aluminum in drinking water and Alzheimer's disease (AD), and between aluminum in dialysate and dialysis dementia. The exact role of aluminum in the pathogenesis of these and other dementias is not clear. This study examined the acute effects of aluminum on cognitive function in patients with AD and related dementias and in age-matched and younger volunteers with normal cognitive function. Whether individuals with AD and/or the APOE epsilon4 genotype had enhanced gastrointestinal absorption of aluminum was tested, and whether individuals with elevated blood aluminum concentrations exhibited acute cognitive effects was determined. Subjects were randomized to receive a single dose of aluminum orally (Amphojel plus citrate) for 3 d followed by a 3-wk washout, and then 3 d of matched placebo administration, or vice versa. Serum aluminum levels were measured and the daily dose of Amphojel was adjusted to a target aluminum level between 50 and 150 microg/L. Neuropsychological tests were administered at baseline and 90 min after the third dose of Amphojel or placebo. There was a large interindividual variation in aluminum serum levels in all study groups after the same initial dose of Amphojel. There were no significant differences in neuropsychological test scores after aluminum ingestion in normal volunteers or in patients with cognitive impairment. There was no association between APOE epsilon4 genotype and aluminum absorption. The results did not support the hypothesis that aluminum ingested at these doses produces acute effects on cognition or adverse effects, nor did they reveal that AD patients are more vulnerable to such outcomes. Further inquiry is required to explore any possible association between aluminum and cognition, but controlled trials may be limited by safety concerns.

A tap water turbidity crisis in Tel Aviv, Israel, due to technical failure: toxicological and risk management issues

Herein, we report on the actual events linked to an ammonia spillage into the main waterline of the Tel-Aviv metropolitan area and its surrounding municipalities. Based upon a large magnitude increase of unknown origin in the turbidity and ammonia levels of the main drinking water supply, area residents were warned of possible serious contamination and advised to refrain from drinking tap water until further notice. Turbidity was later linked only to CaCO3, which was precipitated from the water due to the rise in pH caused by the excessive ammonia levels. The source of the ammonia (a malfunction of the measurement buoy in the ammonia tank) was not identified until several days after the warning was issued. The toxicological implications of the turbidity and ammonia elevations are considered and reconciled with the management strategies that followed. Of consequence to the management of this crisis was the approach of Ministry of Health officials to regard the ammonia, from the onset, as an indicator of several possible sources of origin rather than as a contaminant. Decision-making policies were hampered by ineffective communication between the national water supplier and government health officials. An outcome of this crisis was a heightened awareness of the potential of a water crisis occurring during peace time and not only in association with terrorist activities, to which Israeli citizens are highly sensitized. Finally, the present paper may serve to guide municipal environmental and health officials more appropriately in the event of similar drinking water crises in Israel or elsewhere.

Disturbance of cerebral function in people exposed to drinking water contaminated with aluminium sulphate: retrospective study of the Camelford water incident

OBJECTIVE

To establish whether people exposed to drinking water contaminated with 20 tonnes of aluminium sulphate in the Camelford area of Cornwall in the south west of England in July 1988 had suffered organic brain damage as opposed to psychological trauma only.

DESIGN

Retrospective study of affected people.

PARTICIPANTS

55 affected people and 15 siblings nearest in age to one of the group but who had not been exposed to the contaminated water were studied.

MAIN OUTCOME MEASURES

Various clinical and psychological tests to determine medical condition and anxiety levels in affected people. Assessment of premorbid IQ (pFSIQ) with the national adult reading test, a computerised battery of psychomotor testing, and measurement of the difference in latencies between the flash and pattern visual evoked potentials in all participants.

RESULTS

The mean (SE) pFSIQ was above average at 114.4 (1.1). The most sensitive of the psychomotor tests for organic brain disease was the symbol digit coding (SDC) test (normal score 100, abnormal <85). PARTICIPANTS performed less well on this test (54.5 (6.0)) than expected from their pFSIQ (P<0.0001) and a little less poorly on the averaged less discriminating tests within the battery (86.1 (2.5), P<0.0001). In a comparison with the 15 sibling pairs (affected people's age 41.0 (3.3) years v sibling age of 42.7 (3.1) years (P=0.36) the exposed people had similar pFSIQ (114.7 (2.1)) to their siblings (116.3 (2.1), (P=0.59) but performed badly on the symbol digit coding test (51.8 (16.6)) v (87.5 (4.9) for siblings, P=0.03). The flash-pattern differences in exposed people were greater than in 42 unrelated control subjects of similar age (27.33 (1.64) ms v 18. 57 (1.47) ms, P=0.0002). The 15 unexposed siblings had significantly better flash-pattern differences than their affected siblings (13.4 (2.4) ms v 29.6 (2.9) ms, P=0.0002). No effect of anxiety could be shown on these measurements from the analysis of the anxiety scores of exposed people.

CONCLUSION

People who were exposed to the contaminated water at Camelford suffered considerable damage to cerebral function, which was not related to anxiety. Follow up studies would be required to determine the longer term prognosis for affected individuals.

Aluminium-induced biphasic effect

Increased bioavailability of aluminium has raised concerns about the toxic effect of aluminium. The cholinotoxic effect of aluminium is already well established. The biological response of an organism following exposure to a chemical may be biphasic. Although aluminium-induced biphasic change has been reported in diverse organ systems, the biphasic effect on cholinergic system has received less attention. In vitro and in vivo studies have demonstrated an aluminium-induced biphasic effect on the marker enzyme of cholinergic system, acetylcholinesterase. The biphasic effect of aluminium on the acetylcholinesterase enzyme activity may be due to the direct neurotoxic effect of the metal and the level of aluminium accumulated. Among various hypotheses, peroxidation-induced changes in the structure of membrane following aluminium accumulation seems to explain the biphasic effect of aluminium on acetylcholinesterase activity.

Neuropsychological and stress evaluation of a residential mercury exposure

Residents of a former factory building converted to apartments were exposed to mercury over a 2-year period. The neurobehavioral and emotional health effects of this exposure and subsequent evacuation are presented. Urine mercury levels were measured before (urine1) and 3-10 weeks after evacuation (urine2) of the building, when neurobehavioral and psychological measures were also completed. Performance on neurobehavioral and psychologic measures were compared between subjects above and below the median for urine1 (>=19 microg/g creatinine) and were correlated with urine1 mercury levels. The high urine mercury group made more errors on a test of fine motor function and 84% of the residents reported clinically significant elevations in somatic and psychologic symptoms. Although subclinical tremor from mercury exposure may have affected subtle hand-eye coordination, other tests of motor function were not affected. Therefore, the observation of reduced hand-eye coordination may be due to chance. Significant levels of psychosocial stress were more closely associated with the evacuation necessitated by mercury exposure rather than a direct effect of mercury exposure.

Aluminum exposure and metabolism

Aluminum (Al) is a nonessential, toxic metal to which humans are frequently exposed. Oral exposure to aluminum occurs through ingestion of aluminum-containing pharmaceuticals and to a lesser extent foods and water. Parenteral exposure to aluminum can occur via contaminated total parenteral nutrition (TPN), intravenous (i.v.) solutions, or contaminated dialysates. Inhalation exposure may be important in some occupational settings. The gut is the most effective organ in preventing tissue aluminum accumulation after oral exposure. Typically gastrointestinal absorption of aluminum from diets is < 1%. Although the mechanisms of aluminum absorption have not been elucidated, both passive and active transcellular processes and paracellular transport are believed to occur. Aluminum and calcium may share some absorptive pathways. Aluminum absorption is also affected by the speciation of aluminum and a variety of other substances, including citrate, in the gut milieu. Not all absorbed or parenterally delivered aluminum is excreted in urine. Low glomerular filtration of aluminum reflects that most aluminum in plasma is nonfiltrable because of complexation to proteins, predominantly transferrin. The importance of biliary secretion of aluminum is debatable and the mechanism(s) is poorly understood and appears to be saturable by fairly low oral doses of aluminum.

Modifiers of non-specific symptoms in occupational and environmental syndromes

Many occupational and environmental health hazards present as an increased reporting of non-specific symptoms such as headache, backache, eye and respiratory irritation, tiredness, memory problems, and poor concentration. The pattern and number of such symptoms is surprisingly constant from hazard to hazard suggesting that common psychological and social factors, not directly related to the exposure may be involved. A recent workshop (see acknowledgements) was held to review the pattern of symptoms in varying hazardous situations and the psychological mechanisms behind the genesis and maintenance of symptoms. The involvement of both direct physicochemical and psychological mechanisms in symptom generation and reporting in any situation was discussed and is reported here. A model that identifies the issues that need to be considered in any epidemiological study based on the incidence or prevalence of non-specific symptoms is proposed.

Psychological testing on schoolchildren before and after pollution of drinking water in North Cornwall

The tap water supply in Camelford, North Cornwall and environs was contaminated by aluminium and other metals in 1988. Richmond tests were routinely given before and after the pollution and here scores are compared between 39 children from schools in the contaminated area and 64 children from Cornish schools outside the polluted area. The study was retrospective and it was not possible to determine whether or how much polluted water individuals had consumed. No differences were found between groups either before or after the pollution accident nor was there any evidence for any sub-group of the polluted group which had been affected. The limits of conclusions which can be drawn from data available are discussed.

Is aluminium an etiologic contributor to alcoholic amnesia and dementia?

Neurotoxicity from excess brain exposure to aluminium (Al) is well-documented, from both clinical observations and animal experiments, to impair learning, memory and cognition. The etiology of the cognitive impairment in chronic abusers of ethanol--alcoholic amnesia or dementia--is not known, but it is likely to be multifactorial. We hypothesize that a slowly-progressive accumulation of Al in the brain, so as to reach functionally-toxic levels, may be one such factor. This could occur because of an increased permeability of intestinal mucosa to entry of Al, arising from sustained exposure of the gastrointestinal tract to alcoholic beverages, plus a trend for more frequent ingestion of antacids based on Al salts for treating gastritis or ulcers caused by such exposure. If this be true, use of Al-containing medications, as well as all avoidable exposures to Al, should be contra-indicated for chronic heavy drinkers.