Organic compounds temporal trends at some invertebrate species from the Balearics, Western Mediterranean

Concentrations of persistent organic pollutants (POPs) such as hexachlorobenzene (HCB), dichlore diphenyl trichloretane (DDT), polychlorinated biphenyls (PCBs), and gamma-hexachlorocyclohexane (gamma-HCH or lindane) were determined in tissue of marine benthic invertebrates such as Mytilus galloprovincialis, Chamelea gallina, Venus verrucosa, Lithophaga lithophaga and Paracentrotus lividus. Species were selected due to their habitat, trophic level, feeding behaviour and their consumption. Invertebrate species were systematically sampled from December 1996 to December 2005 from several sites along the Balearic Islands. The highest concentrations of PCBs (785ng/g lipid) were found in M. galloprovincialis while the lowest concentrations were found in the sea-urchin P. lividus (193ng/g lipid). Among the 7 PCB quantified congeners the higher values are mainly obtained for CB138 and CB153. All bivalves presented higher PCBs contents than the sea-urchin P. lividus are possibly linked with the bioaccumulation process of POPs throughout the food web and to differential detoxifying mechanisms. The concentration of SigmaDDT exceeds that of HCB and gamma-HCH at all species and sampling stations. DDT concentrations ranged from 0.4ng/g ww at the bivalve C. gallina in 2002, to values of 15.8ng/g ww at the bivalve L. lithophaga in 1998. The values obtained for the organic compounds (HCH, HCB, PCBs, DDT) depend upon the place and year of sampling and are compared to values found by other authors for the mussel M. galloprovincialis in other Mediterranean areas. gamma-HCH and HCB were found in lower concentrations than the other POPs.     

Quantitation of metallothionein and cadmium in metallothionein in mink livers by anion-exchange HPLC-GFAAS method

Metallothionein (MT) has a great capacity of binding heavy metals showing an interesting connection with metal toxicology, as a biochemical marker for environmental metal pollution. Anino-exchange high per formance liquid chromatography (HPLC) was used to isolate and quantitate MT in livers of minks which were contaminated with heavy metals. MT isoforms (MT-I and MT-II) were eluted at approximately 11.3 and 14.3 min respectively from a DEAE-5 PW anion-exchange column with a Tris-HCl buffer (0.01 -0.25 mol/L, pH 8.6) and detected by UV absorbance at 254 nm. The cadmium concentrations in mink liver MT elutkms were determined by graphite furnace atomic absorption spectrometry (GFAAS) . Obvious increase in liver MT-I concentration rather than liver MT-II was found when the minks were contaminated by feeding contaminated fish captured from the heavy metal-polluted river. The cadmium concentration in mink liver MT-I also increased to some extent as the contaminated level increased.     

Photochemical reaction of particle-bound 1-nitropyrene under simulated atmospheric condition

Photoreaction of particle-bound 1-nitropyrehe (1-NP) under simulated atmospheric condition has been studied. When 1-NP coated on the surface of silica gel was suspended in a stream of nitrogen, oxygen or air, respectively, and exposed to intensive light of xenon lamp, photochemical reaction took place. The result of kinetic study showed it to be of the second order. The photoreaction products were identified by off-line HPLC/MS as 1,6-pyrenequinone, 1,8-pyrenequinone, trinitro-hydroxypyrene, dinitrohydroxypyrene, 6,6'- dipyrenenone, etc. The mutagenicity of photochemical reaction products is higher in oxygen and air, and lower in nitrogen than that of the precursor 1-NP, as detected by the Ames Bioassay.     

Analysis of Los Angeles Photochemical Smog Data: A Statistical Overview

A research project has been under way to investigate air pollution problems in Los Angeles County with the help of the data supplied by the Los Angeles County Air Pollution Control District. These data consist of measurements of primary pollutants such as nitric oxide, hydrocarbons, carbon monoxide, sulfur dioxide and particu-lates, and secondary pollutants such as ozone and nitrogen dioxide, recorded hourly at a number of different stations in Los Angeles County over the past seventeen years. This present discussion deals in a preliminary way with a particular aspect of this analysis, namely, the occurrence of photochemical smog in Los Angeles. The paper is divided into two main sections. The first is intended to provide a brief survey of the problem of photochemical smog in Los Angeles as presently understood in relation to the available field data and also in relation to chamber experiments which have been run in various laboratories. The second part of the paper discusses a class of intervention problems that arise in studying the data. It is noted that parallel problems occur in the study of other ecological material and elsewhere. Statistical methods for dealing with this class of problems are illustrated with some of the Los Angeles data.     

A Statistical Analysis of the Los Angeles Ambient Carbon Monoxide Data 1955–1972

This paper presents a statistical analysis of some aspects of the ambient carbon monoxide data from 1955 to 1972 recorded at seven appropriately distributed locations in the Los Angeles Basin. Using modern time series methods and graphical techniques, an overall trend analysis of the movement of CO is given. Of special interest is a detailed study of the effect on the observed concentration level of CO due to (i) a change in the method of calibration of the measuring instrument In April 1968 and (ii) various control measures introduced since 1966. Also presented is an analysis of the seasonal variation of CO and the diurnal variation in weekdays and weekends. A major purpose of this study is to assess the influence of meteorological variables on the concentration level of the pollutant. Appropriate mathematical models are developed which relate CO to inversion base height, maximum mixing height, wind speed and direction, and traffic pattern. In addition, an analysis of the meteorological conditions during the days in which hourly concentration level of CO exceeded the Federal Air Quality Standard is given.     

Determination of total arsenic by photo-decomposition of organoarsenic compounds and hydride generation electrothermal atomic absorption spectrometry

A method was developed for the determination of total arsenic concentration in less than ng/ml level by decomposition of organoarsenicals using photo -oxidation combined with in situ trapping of arsenic hydride on a palladium coated graphite tube with subsequent atomization and detection by AAS. The organoarsenicals include monomethylarsenic, dimethylarsenic, arsenobetaine, arsenocholine, o -aminobenzenarsenate and p -aminobenzenarsenate. The method is simple and sensitive. Detection limit was obtained from different arsenic compounds over the range from 0. 058 to 0.063 ng/ml as As (based on three times of the standard deviation of 10 blank measurements) and the relative standard deviations for ten replicate measurements were from 2.0 to 3.8%. The calibration curves of arsenic compounds including inorganic and organic arsenicals were linear over the range from 0.1 to 3.0 ng/ml as As. The recommended method has been applied to the determination of total arsenic in tap and lake water samples at ng/ml leve     

Some Empirical Models for the Los Angeles Photochemical Smog Data

This paper presents (i) an empirico-mechanistic model which describes the dependence of CO, NO, NO₂, and O₃ on total hydrocarbons, traffic, wind speed, inversion base height, and solar radiation as well as the photochemical reactions associated with these pollutants; (ii) a detailed study of weather conditions when the instantaneous daily maximum O₃ exceeds the L.A. County alert level of 50 pphm; and (iii) regression models for the prediction of daily maximum O₃ values.     

Statutory Local Nature Reserves in the United Kingdom

Local authorities in Great Britain have had the powers to acquire, declare and manage statutory Local Nature Reserves since 1949; these powers were extended to Northern Ireland in 1985. As of March 1997, there are some 564 Local Nature Reserves in England, three in Northern Ireland, 24 in Scotland and 38 in Wales. Local Nature Reserves are important for biodiversity and nature conservation at a local level and can have a special role for local schools. The overall situation in respect of Local Nature Reserves has been recently reviewed by the Urban Forum of the UK Man and the Biosphere Committee. This review will add impetus and purpose to the wide variety of programmesand projects involving Local Nature Reserves. It will add emphasis to their potential not only for nature conservation and environmental education but also for community development.     

Study of aerosol composition in some clean areas of China

On Peak Namjagbarwa (Tibet Plateau), Lushan Mountain (Province Jiangxi), Flower Mountain and Shangdianzi (Beijing, near Great Wall) aerosol samples have been collected by cascade samplers. For comparison aerosol samples from Beijing City, Pacific Ocean and South Pole also have been collected. Samples were analyzed with PIXE or XFA instruments. Factor analysis and enrichment factor calculation were performed to process the data.