Biomarkers in fish as a measure of the state of marine environment of Kuwait

The health of a marine ecosystem can effectively be monitored by studying the levels of biomarkers in a representative species. A change in background level of a biomarker indicates exposure to a specific type of pollutants. It also identifies bioavailability and the organism response to the causative agent among the compounds present in the surrounding water body. Yellowfin seabream (Acanthopagrus latus), a local variety of fish, was examined for parent PAHs in the liver, its metabolites in bile by the GC-MS method as exposure biomarkers and cytochrome P4501A1 by assay of ethoxyresorufin-o-deethylase (EROD) in the liver as an effect biomarker. A comparison was made between fish collected in 2015 with the fish collected in 2005-2006 and stored at - 80 °C in the fish bank. The objective was to examine the extent of changes in the environmental quality of the Kuwait marine area and the status of fish health concerning oil-related pollutants since Arabian Gulf is surrounded by oil-producing countries. Interestingly, insignificant differences between the liver PAH content and EROD activity were observed in fish over the sampling periods. The fish efficiently metabolized PAHs and excreted hydroxy-metabolites in bile. The study suggested that environmental quality of the Kuwait marine area was not deteriorated to any serious extent in the last decade and biomarkers can be used effectively in assessing the thrust of sub-optimal levels of various contaminants present in the marine area on the resident biota.

Seasonal effect on biomarkers of exposure to petroleum hydrocarbons in fish from Kuwait's marine area

The aquatic biota of the Arabian Gulf deals with exposure to chronic oil pollution, several constituents of which cause induction of Cytochrome P450 1A that serves as a biomarker of AhR ligand exposure. In this study, fluorescent aromatic compounds (FACs) in bile and 7-ethoxyresorufin-o-deethylase (EROD) catalytic activity were determined as a measure of exposure biomarkers in two fish species, yellow fin seabream (Acanthopagrus latus) and tonguesole (Cynoglossus arel) captured from Kuwait Bay and outside the Bay area. FACs in fish bile determined by using fixed-wavelength fluorescence (FF) showed high fluorescence ratios between FF290/335 and FF380/430 indicating predominant exposure to low molecular weight, naphthalene-rich petroleum products (375±91.0 pg ml(-1)). Exposures to benzo(a)pyrene-type high-molecular weight polycyclic aromatic hydrocarbons (PAHs) originating from burnt fuel were also present in appreciable concentration in the bile. The ratio of petrogenic to pyrogenic hydrocarbon was twofold higher in winter compared to summer months in both species. Seasonal effect on EROD was significant in tonguesole in Auha site (P<0.05); whereas seabream resisted seasonal change. Tonguesole is considered to be a suitable bioindicator of oil pollution in Kuwait Bay area.

Metallothionein, oxidative stress and trace metals in gills and liver of demersal and pelagic fish species from Kuwaits' marine area

Two fish species yellowfin seabream (Acanthopagrus latus) and tonguesole (Cynoglossus arel) were collected from two locations in Kuwait's territorial waters in non-reproductive periods and used as bio-indicator organism for the assessment of metals in the marine environment. Species variation in fish was observed; seabream contained high metal content and metallothionein in liver and gill tissues compared to tonguesole, especially from Kuwait Bay area. Oxidative injury was registered in the gills of both species, but in tonguesole liver was also involved. Consequently, antioxidant enzyme catalase was elevated in tonguesole enabling bottom dwelling fish to combat oxidative assault. The study provided information about the current status of metals in marine sediment and levels of metals accumulated in representative species along with oxidative damage in exposed tissues and the range of biomarker protein metallothionein and enzymes of antioxidant defence mechanism enhancing our understanding about the biological response to the existing marine environment in Kuwait.

Mycotoxins in poultry feed in Kuwait

A survey was conducted at a poultry feed production unit in Kuwait for mycotoxin contamination in the samples of yellow maize, soybean meal, wheat bran used as raw material and the poultry feed prepared for broiler starter, broiler finisher, and layer mash. Individual aflatoxins were determined by high-pressure liquid chromatography after immunoaffinity column purification. Repeated analysis revealed average aflatoxin concentration in maize at 0.27 ppb (range 0 to 1.69 ppb), soybean meal at 0.20 ppb (range 0 to 1.27 ppb), wheat bran at 0.15 ppb (range 0 to 1.07 ppb), prepared poultry feed for broiler starter at 0.48 ppb (range 0 to 3.26 ppb), broiler finisher at 0.39 ppb (range 0 to 1.05 ppb), and layer mash at 0.21 ppb (range 0 to 1.30 ppb). Other mycotoxins (ochratoxin, fumonisin, deoxynivalenol (DON), and zearalenone), were detected by quantitative enzyme-linked immunosorbent assay. The average levels of ochratoxin A ranged from 4.6 to 9.6 ppb, fumonisin from 1.4 to 3.2 ppm, DON from 0.17 to 0.29 ppm, and zearalenone from 46.4 to 67.6 ppb in various commodities and prepared feed samples. The study revealed the coexistence of determined mycotoxins, although their concentrations in general were found to be lower than the permissible levels, wherever defined, for the poultry feed.

Distribution of petroleum hydrocarbon in sediment from coastal area receiving industrial effluents in Kuwait

Sediment samples from the coastal area facing Shuaiba industrial area (15 x 1.5 km(2)) were examined for contamination with petroleum hydrocarbons. Aliphatic hydrocarbons in sediment extracts were characterized largely by unresolved complex mixture from nC(22)-nC(33). The sediment samples from the upstream area facing Mina Al-Ahmadi refinery to Shuaiba Harbor were heavily polluted with polycyclic aromatic hydrocarbons (PAHs) possibly due to the higher depth in the area created for a navigational channel to the harbor. PAHs at these locations exceeded the probable effect levels with reference to sediment quality guidelines.

Chemical contamination and toxicity of sediment from a coastal area receiving industrial effluents in Kuwait

The Shuaiba coastal area (12.5 x 1.5 km) was examined for contamination with total organic carbon, volatile organic matter, total petroleum hydrocarbons, polycyclic aromatic hydrocarbons, cadmium, chromium, copper, lead, nickel, vanadium, and zinc in sediment; their desorption by aqueous elution; and toxicity to aquatic biota. The pollutants were mainly accumulated in the upstream area facing Mina Al-Ahmadi refinery to Shuaiba harbour. Solid-phase Microtox assays showed severe toxicity, and the LC(50) was negatively correlated with most of the chemical parameters, suggesting that toxicity was the function of collective effects of the pollutants present in sediment. Sea water elutriation showed poor desorption of pollutants from sediment, and the elutriates were not found toxic to Microtox and brine shrimp larvae. Whole sediment suspension in sea water reduced the survival of fingerlings in fish bioassays. Action from Shuaiba Area Authority is required to reduce pollutant accumulation in identified depositional area on the Shuaiba coast by facilitating unrestricted water flow in the area and restricting pollutant discharge at source.

In vitro selection of endosulfan-tolerant strains of Brassica compestris (cv. Brown Sarson)

Endosulfan tolerant lines of mustard (Brassica campestris cv. Brown Sarson) have been developed through tissue culture methods. Cotyledonary expiants excised from eight day old in vitro grown seedlings were used for inducing callus. Fast growing friable callus was then transferred to MS medium containing (0.1-2.0 ugl(-1)) endosulfan for selection. Five alternating exposures with and without endosulfan containing medium yielded an endosulfan tolerant cell line (ETL). The plants regenerated from ETL were found to tolerate three fold higher concentrations of endosulfan. Callus induced from randomly selected endosulfan tolerant regenerated plants were also tolerant to 3.0 ugl endosulfan, thereby, suggesting that tolerance has been acquired at the gene level.Biochemical investigation revealed higher levels of total free sugar, free amino acids, protein and activity of peroxidase in the tolerant cell line.

Effect of intratracheally administered lindane on aldrin and benzo(a)pyrene contents in lungs of rats

Pretreatment with lindane resulted in inhibition of benzo(a)pyrene hydroxylase activity in the lungs of rats. The enzyme activity tended to return to normal 5 days after the administration of lindane. Studies with benzo(a)pyrene and aldrin indicated reduced elimination of these compounds from the lungs of lindane-treated animals, suggesting that lindane may alter the clearance of certain substances or compounds from lungs. The delayed clearance of these compounds from lungs may be an indirect effect of lindane related to inhibition of certain metabolizing enzymes.

Effects of endosulfan and its metabolites on rat liver mitochondrial respiration and enzyme activities in vitro

Endosulfan (E) is an organochloric insecticide, which is quickly metabolized and eliminated from the body system. Toxic effects of E and its metabolites have been reported. The influence of E and its metabolites, viz. endosulfan sulfate (ES), endosulfan diol (ED) and endosulfan lactone (EL), has been examined on rat liver mitochondria in vitro. Endosulfan stimulated state-4 respiration at lower concentrations and inhibited it at higher ones, whereas state-3 respiration was inhibited at all the concentrations used, i.e. 5-100 micrograms/ml. A maximal 25-fold activation of latent Mg2+-ATPase was achieved at a concentration that caused maximal stimulation of state-4 respiration. Activities of the respiratory chain-linked enzymes were inhibited at levels which corresponded to the concentrations of endosulfan used in vitro. Both the respiratory control ratio (RCR) and the ADP:O ratio fell sharply at endosulfan concentrations above 10 micrograms/ml. ES and ED exerted similar effects on mitochondrial oxidation of beta-hydroxybutyrate, but at more than double the concentration of the parent compound, while EL proved least effective. The effects of the latter compound on mitochondrial enzyme activities were negligible. Our results suggest that endosulfan possesses dual properties, that of an uncoupler of oxidative phosphorylation and of an inhibitor of the electron transport chain, and that the in vivo cytotoxic/insecticidal effects of endosulfan and its metabolites might, therefore, be the consequence of impaired mitochondrial bioenergetics.

Dissolution of silicic acid from amosite and quartz dusts under physiological conditions

The dissolution of silica from amosite dust in human serum and in Ringer buffer at 37 degrees C was found to be significantly higher than that from quartz. The significance of this finding in relation to their fibrogenic effects has been discussed.