The feeding habits of several fish species in a water reservoir of the Ria Formosa, Portugal, that has similar ecological characteristics to the outside tidal channels, were studied and compared with food availability. The gilthead seabream (Sparus aurata), the most abundant fish species, mainly selected gastropods and bivalves, although occasionally fish and small crustaceans such as tanaids, ostracods, and cumaceans were also selected. Polychaetes, although abundant in the environment, were not particularly selected by any of the fish species studied. The diets of all the species studied were characterized by a large variety of prey, allowing them to survive in environments of low diversity and poor stability, such as coastal lagoons. These fish are largely benthic feeders, essentially eating the epimacroinvertebrates and endomacroinvertebrates and, occasionally, fish. Diplodus vulgaris and Diplodus annularis preferentially selected gastropods and small crustaceans. Spondyliosoma cantharus generally preyed on crustaceans, including the highly mobile epifauna, the mysids, and decapods. Halobatrachus didactylus and Anguilla anguilla, had very diversified diets that included fish. Mullus barbatus were found to have selected all groups of crustaceans and also bivalves. Wrasses, gobies, and Diplodus sargus, all small-sized fish, singled out small crustaceans, gastropods, and bivalves. The Sparids were the least specialized predators, with broader niches than the other species. They preferentially selected molluscs, which were abundant in the environment. A large overlap of diets was observed and competition may be important when fish biomass is high.

Steam injection heating systems for food and agricultural products are subject to condensation-induced water hammer (CWH), which may cause significant damage to equipment and pose a threat to operators. A method is suggested for process design and operation of a steam injection heater that reduces occurrence of CWH. The method is based on a correlation between the thermodynamic ratio of the product and the Peclet number. A laboratory steam injection heater was instrumented to determine the relationship between CWH, the thermodynamic ratio, and the Peclet number. The thermodynamic ratio for water and various concentrations (55 to 67.5 brix) of sucrose solution was recorded under process conditions at the onset of CWH during steam injection heating. Good correlation was observed between the Peclet number and threshold thermodynamic ratio. A linear equation was found (with r 2 = 0.79) that gives the predicted minimum thermodynamic ratio for system operation without CWH.

To evaluate the base line levels of potentially toxic and essential trace metals namely, Cd, Ph, Cr, Mn, Ni, Cu and Zn in water, locally grown vegetables, cereals and vegetable ghee-oil samples of a highly industrial city Gujranwala have been measured after wet digestion by employing AAS technique. Sampling was made from selected sites in and around the city over a period of three months. The concentration of Mn, Ni, Zn, Cu and Pb was found significantly higher in vegetables ranging from 3-63, 2-81, 5-92, 7- 70 and 6-60 ppm respectively. Nickel and Cu concentration was found higher in cereals whereas, Cd was found at ppb level in all variety of samples studied. Tap water, vegetable ghee-oil have recorded lower concentration of these metals. Vegetables collected from urban area have shown elevated level of contamination than those of taken from canal irrigated farms. The overall level of trace metals with few exceptions of vegetable samples was found within the permissible limits fixed by WHO. The analytical method was checked by applying on SRM of wheat and spinach. The results were found in agreement with the certified values within experimental error. The major polluting sources of the city such as automobile, man made activities, soil and road dust, metallic corrosion and industrial activities have been indicated. The environmental impacts of pollutants on water and food quality of an industrial and non-industrial city are briefly discussed in the light of their adverse effects on human health.