Search results for "water pollution"

A survey of recent results in passive sampling of water and air by semipermeable membrane devices

1995

Abstract A survey is presented of some recent results for passive sampling of water and air for trace organic contaminants using lipid-filled semipermeable membrane devices (SPMDs). Results of water sampling for trace organochlorine compounds using simultaneously exposed SPMDs and the most universally applied biomonitor (bivalves) are discussed. In general, the total amounts of accumulated analytes available for analysis in bivalves and SPMDs were comparable. However, SPMD controls typically had negligible levels of contamination, which was not always the case for transplanted bivalves, even after prolonged depuration prior to exposure. In surveys of the spatial trends of organochlorines at…

An environmental study by factor analysis of surface seawaters in the Gulf of Valencia (Western Mediterranean)

1999

Abstract A study is made on the quality of coastal waters in the Gulf of Valencia (Spain) in terms of contamination markers including microbiological agents, toxic heavy metals and nutrients that adversely affect the environment. Relationships are also established between these factors and other physical and chemical parameters. A multivariate analysis is conducted where a total of 14 parameters are established for 919 water samples corresponding to 52 sampling points along the coast of the province of Valencia – specifically, total and fecal coliforms, fecal streptococci, Ni(II), Zn(II), Pb(II), Cd(II), Cu(II) and Cr(VI) concentrations, nitrates, phosphates, dissolved oxygen and finally pH…

Levels of heavy metals in some marine organisms from the western Mediterranean area (Spain)

1994

Inorganic polyphosphates in the developing freshwater spongeEphydatia muelleri: Effect of stress by polluted waters

1996

Relatively high amounts of inorganic polyphosphates (approximately 55 μg of polyphosphate/g of wet weight) were found in the freshwater sponge Ephydatia muelleri, particularly in the gemmules (260 μg/g). Here we report that the polyphosphate content of this sponge changes during development and in response to adverse environmental conditions. Germination and hatching of gemmules of E. muelleri is accompanied by a strong decrease (by 94% at day 2) in polyphosphate level and a rise in exopolyphosphatase activity. On the other hand, induction of gemmulogenesis by theophylline results in an increase (by 61%) in polyphosphate content of sponge tissue. An increase in polyphosphate content and a d…

Effect of substituted phenols on transaminase activity in the fish,Leuciscus idus melanotus L.

1986

Model ecosystem for environmental transport of xenobiotics

1982

A compartmentalized aquatic-terrestrial flow-through model ecosystem was constructed for studying the transport of agricultural chemicals from the soil to the aquatic environment in soil drainage. Factors were investigated on the fate of reference toxicant,14C-DDT, in the subsystems of the model. The behavior of DDT corresponds to its behavior in natural soil/water systems. The soil, acting as a reservoir, retained most of the DDT. The transportation of DDT to the aquatic compartment was negligible, with low availability to the aquatic biota. Because of the dynamic nature of the model, variation was evident between and within model units.

Effect of wastewater management on phosphorus content and sedimentary fractionation in Mediterranean saline lakes

2019

The La Mancha Húmeda Biosphere Reserve is the largest wetland district in the Iberian Peninsula, containing many temporary saline lakes undergoing different anthropogenic pressures. Eleven of these lakes were selected to assess phosphorus (P) burial, fractionation and mobilization in their sediments. Wastewater inputs, wherever they occurred, favored accumulation of all P sedimentary fractions, which took place mainly via precipitation with divalent cations (i.e. calcium or magnesium) and as buried organic matter, both representing relatively occluded P forms, although they can also be involved in P release. P immobilization would be partially restrained in the volcanic lakes of the region,…

Microwave-assisted extraction of OCPs, PCBs and PAHs concentrated by semi-permeable membrane devices (SPMDs)

2005

Abstract Microwave-assisted extraction (MAE) has been evaluated as an alternative to dialysis for extraction of some water-borne hydrophobic contaminants sampled by semi-permeable membrane devices (SPMDs). Seven organochlorine pesticides (OCPs), 11 polychlorinated biphenyls (PCBs) and 13 polycyclic aromatic hydrocarbons (PAHs) were accumulated in SPMDs at nanogram levels and extracted with three 3-min irradiation cycles with 33 mL of a solvent mixture hexane–water (10:1,v/v) in each cycle. The developed MAE method gave for all analytes investigated statistically comparable extraction yields with those found by dialysis carried out with a total volume of 250 mL hexane for 48 h at room temper…

Direct Solid Phase Microextraction for the Determination of BTEX in Water and Wastewater

1996

Determination of heavy metal complexes with humic substances by HPLC/ICP-MS coupling using on-line isotope dilution technique

1997

An isotope dilution mass spectrometric (IDMS) method has been developed for the simultaneous determination of the complexes of 11 heavy metals (Ag, Cd, Cu, Mo, Ni, Pb, Tl, U, W, Zn and Zr) with humic substances (HS) by coupling HPLC with ICP-MS and applying the on-line isotope dilution technique. The HPLC separation was carried out with size exclusion chromatography. This HPLC/ICP-IDMS method was applied to samples from a brown water, ground water, sewage and seepage water as well as for a sample containing isolated fulvic acids. The total contents of heavy metals and of their complexes were analyzed in these samples with detection limits in the range of 5–110 ng/L. The analysis of heavy me…