Assessment of well water quality in Tsunami affected regions of south-west coast of Kerala, India.

The quality of well waters, based on 23 parameters of water, at 12 stations of south-west coast of Kerala, India, was assessed during monsoon, 2009 and summer, 2010, to determine their suitability for drinking and other domestic purposes. The stations selected were grouped into four regions viz. least, slightly, moderately and severely affected ones based on the severity of 2004 Asian Tsunami at each station. The depths of wells showed variations depending on the seasons and on their distance from the seacoast. The average water temperatures during monsoon and summer seasons were 28.5oC and 30.2oC respectively. The pH of well waters were below 6.5 in least and slightly affected regions and above this value in moderately and severely affected regions. In all the four regions, the well water parameters of electrical conductivity, hardness, fluoride, free chlorine, copper, zinc, calcium and nickel were below, and phosphorus, lead, iron cadmium and manganese were above the standard permissible levels set for them in drinking water. The values of salinity, sodium and potassium in the well waters of moderately and severely affected regions, and the values of nitrate-nitrogen, nitrate and magnesium in the well waters of severely affected regions were above the permissible limits set for them in drinking water. Water quality index calculated on the basis of drinking water standards revealed that the well waters of least and slightly affected regions were moderately polluted in both monsoon and summer seasons and the same of moderately affected region were excessively polluted during monsoon and severely polluted during summer seasons, whereas the well waters of severely affected regions were severely polluted in both seasons. Suitable recommendations were made to improve the quality of well waters of least and slightly affected regions.

Risk assessment of the amnesic shellfish poison, domoic acid, on animals and humans.

Risk assessment of the amnesic shellfish poison, domoic acid, a potent neurotoxin, is evaluated based on its current knowledge and its harmful effects, and is presented under four headings, viz., (1) hazard identification, (2) dose response assessment, (3) exposure assessment and (4) risk characterization. Domoic acid binds the glutamate receptor site of the central nervous system (CNS) of humans and causes depolarization of neurons and an increase in cellular calcium. In nature, domoic acid is produced by the algae, Pseudonitzschia spp. and they enter into the body of shellfish through their consumption. This toxin is reported to cause gastroenteritis, renal insufficiency, confusion and memory loss in humans, since it affects the hippocampus of the brain. In rats, intraperitonial and oral administration of domoic acid result in scratching, tremor and convulsions, and in monkeys, the toxic symptoms like mastication, salivation, projectile vomiting, weakness, teeth grinding and lethargy are apparent. The no-observed-adverse-effect-level (NOAEL) in animals reveals that pure toxin is more effective than those isolated from shellfish. Based on LD50 values, it is found that intraperitonial administration of this toxin in animals is 31 fold more effective than oral administration. Low levels of domoic acid (0.20 – 0.75 ppm) show no toxic symptoms in non-human primates, but clinical effects are apparent in them and in humans, at a concentration of 1.0 ppm. The tolerable daily intake (TDI) of domoic acid for humans is calculated as 0.075 ppm, whereas for razor clams and crabs, the TDI are 19.4 and 31.5 ppm respectively. The hazard quotient (HQ) is found to be 2. Being an irreversible neurotoxin, domoic acid has severe public health implications. Death occurs in those above 68 years old. In order to ensure adequate protection to public health, the concentration of domoic acid in shellfish and shellfish parts at point of sale shall not exceed the current permissible limit of 20 μg g-1 tissue. While processing shellfish, it may be advisable to pay attention to factors such as environmental conditions, inter-organ variability in concentrations of domoic acid and cross contaminations.

Groundwater quality of north-east Libya.

The quality of groundwater was assessed to their suitability for drinking at six places of north-east Libya viz. El-Marj, Albayda, Shahat, Susa, Ras al-Hilal and Derna, during November, 2003 to March, 2004, by determining their physicochemical parameters (17 parameters) and water quality index (15 parameters). The temperatures of water samples averaged 15.1 degree C, pH values were alkaline and dissolved oxygen values were in safe ranges. Electrical conductivity, total dissolved solids and hardness of water at all places except Susa were within the standard limits. Alkalinity of well water at all six places exceeded, and chlorine and chloride (except Susa) were within the desirable limits set for them. Fluoride and nitrate contaminations of well water were not observed, and only very low values of phosphorus, manganese, chromium, iron and zinc were recorded. Copper in well water was generally high, and at Susa and Ras al-Hilal, it exceeded the desirable limit. Parametric ratios showed that all parameters studied except those of pH, dissolved oxygen, alkalinity and total chlorine originated from sources different from that of hardness. Water quality index (WQI) revealed that well water of Albayda and Shahat were good for drinking and were only slightly polluted, whereas those of El-Marj, Ras al-Hilal and Derna were moderately polluted. However, the well water of Susa was excessively polluted and was unsuitable for drinking. Suitable suggestions were made to improve the quality of groundwater of N.E. Libya.

Body mass and cuticular transpiration of the pulmonate slug Milax rusticus treated with spinach homogenate filtrate.

The effects of four concentrations (25, 50, 75, 100%) of spinach homogenate filtrate over a period of 96 hours on the body mass and transpiration rates of the pulmonate slug Milax rusticus, a crop pest found in Benghazi, Libya, are reported. A decrease in body mass and transpiration rate in filtrate treated slug over time was evident and the differences in these factors between control and treated slug were significant (p < 0.01). Tendencies for regaining lost weight and increase in transpiration were observed in the filtrate treated slugs during their seven days of recovery period in normal conditions. Application of spinach homogenate filtrate as a possible contact slugicide of M. rusticus is suggested.

Earthworm resources of Benghazi, Libya.

This study presents the first survey of earthworm species (Oligochaeta) from Benghazi, a Mediterranean coastal city in Libya. A total of three peregrine species were recorded: Allolobophora caliginosa trapezoides, Allolobophora rosea (Family: Lumbricidae), Microscolex dubius (Family: Microscolecidae). Their distribution and density in six habitats (vegetable garden, flower garden, green house, farmland, grassland, plain barren landscape) are discussed in relation to some of the physico-chemical parameters and composition of the soil.

Toxicity of Nerium oleander leaf extract in mice.

Non-lethal dose of 70% ethanol extract of the Nerium oleander dry leaves (1000 mg/kg body weight) was subcutaneously injected into male and female mice once a week for 9 weeks (total 10 doses). One day after the last injection, final body weight gain (relative percentage to the initial body weight) had a tendency, in both males and females, towards depression suggesting a metabolic insult at other sites than those involved in myocardial function. Multiple exposure of the mice to the specified dose failed to express a significant influence on blood parameters (WBC, RBC, Hb, HCT, PLT) as well as myocardium. On the other hand, a lethal dose (4000 mg/kg body weight) was capable of inducing progressive changes in myocardial electrical activity ending up in cardiac arrest. The electrocardiogram abnormalities could be brought about by the expected Na+, K(+)-ATPase inhibition by the cardiac glycosides (cardenolides) content of the lethal dose.