Abstract Approximately 8 million tons of sewage sludge were disposed of annually at the 106-Mile Deepwater Municipal Sludge Dump Site (106-Mile Site) between 1987 and 1990. Beginning in 1988 and continuing to the present, the focus of monitoring at the 106-Mile Site moved towards improved understanding of the fate of the sludge. A survey conducted in October 1989 was designed to (1) detect the presence of any sludge particles that settle rapidly following disposal, (2) determine if sludge could be detected in the surface waters at locations away from the immediate disposal site, and (3) determine if water quality was degraded, by assessing whether the Environmental Protection Agency's marine water quality criteria were being exceeded. The survey showed that the sludge does have a rapidly settling component composed of organic floc. mineral grains, and other heavy, gritlike particles, all of which are relatively large. These particles may settle at rates of between 8 and 180 m h?1 and may reach the sea floor within 1 to 13 days following disposal. Even though a rapidly settling component is present in the sludge, a significant fraction of the sludge was detectable in the form of intact sludge plumes in the upper 35 m of the water column at least 15 km from the Site. in addition, unique tracers of sludge such as xylem tracheids and Clostridium perfringens plus elevated total suspended solids and trace metals concentrations, were found at locations up to 40 km from the Site. the presence of these tracers correspond with in situ transmissometry data suggesting that a fraction of the sludge was remaining in the near-surface waters above the seasonal pycnocline. Concentrations of metals were below EPA chronic marine water quality criteria, which indicates that the water quality downstream of the Site was not impaired. the detection of sludge downstream of the 106-Mile Site is consistent with the southwestward movement of the surface water mass during the survey, as recorded by satellite-tracked surface drifters and current vectors derived from a current meter moored at 100-m depth immediately west of the Site. Near-surface transport was generally towards the southwest at a speed of approximately 22 cm s?1?. 相似文献
This article investigates available environmental data from measurements of the everywhere present contaminants polychlorinated dibenzo‐p‐dioxins and dibenzofurans (PCDD/F) in dated trends in sediment, soil and herbage from locales in Europe and North America. The PCDD/F data are examined in relation to potential major PCDD/F sources based on volume: wood and coal, example of natural combustion; pentachlorophenol (PnCP), example of chlorinated aro‐matics; and polyvinyl chloride (PVC) pyrolysis, example of chlorinated aliphatic. Collected PCDD/F data of congener sums and 2, 3, 7, 8‐substituted congener (PCDD/F profiles) have been investigated with multivariate methods: principal component analysis (PCA) and partial least squares projection to latent structures model (PLS). The results show that PCDD/F data from 12 locales can be separated in one to three independent profiles. Normally one profile is related to the PCDD/F found in PnCP and another to combustion. A subtype of the ‘PnCP’ and ‘combustion’ profiles indicates PCDD/F contributions from PVC‐related combustions. The environmental profiles exhibit some differences from the suggested sources. The relatively unprotected PCDD/F related to PnCP is suggested to have passed photolytic and/or thermal dechlorinations. Lower‐chlorinated congeners in environmental profiles related to combustion appear to have been influenced by environmental distribution processes. PCDD/F data before industrial production of chlorinated organics have only limited similarity to PCDD/F in technical PnCP profiles; an average 4.6% of the PCDD/F is related to PnCP. This suggests that PnCP similarity in recent deposition profiles cannot be a result of environmental transformation. The average proportion of PnCP‐related PCDD/F profile in recent depositions is 35% with North America high (average 57%) and Europe low (average 24%). 相似文献
The boll weevil, Anthonomus grandis Boheman was introduced from Mexico into the United States about 1892. More than three‐fourths of all insect losses to cotton in this country have been attributed to this insect, and it is generally agreed that cotton cannot be profitably grown in areas where it occurs without adequate control measures. This review summarizes the chemically oriented research conducted on this plant‐insect complex during the past seventy years with emphasis on the program conducted since 1962 at the Boll Weevil Research Laboratory. Of plant‐insect relationships, host plant resistance, feeding stimulants, plant attractants, and plant constituents are discussed. Insect‐insect relationships treated include insecticides, chemosterilants and hormones, sex attractants, and insect constituents. The development of an integrated program for the attempted eradication of this insect is also discussed. 相似文献
The liver is the major site of metabolism of foreign chemicals, but contribution from intestinal biotransformation can influence the overall disposition of chemicals. The intestinal drug‐metabolizing enzymes are located in the endoplasmic reticulum and they possess biochemical properties similar to those of the hepatic system. In general, the rate of in vitro metabolism of drug substrates in intestines is lower than in the liver. There seem to be differences in regulation and induction of hepatic and intestinal drug‐metabolizing enzymes. The in vitro intestinal metabolism of foreign chemicals is affected by several factors including the nutritional status of the animal. Dietary components such as vitamins, lipids and vegetables can modify the activities of intestinal drug‐metabolizing enzymes. Phenobarbital or 3‐methyl‐cholanthrene (3‐MC) pre‐treatment induces the hepatic metabolism of a wide variety of drug substrates in a number of species, while the stimulation of intestinal enzymes is both substrate and species specific. Rabbit intestinal drug‐metabolizing enzymes seem to be resistant to induction by foreign chemicals. 相似文献
Hydrophobicity and bioaccumulation potential of linear and cyclic polydimethylsiloxane (PDMS) oligomers were estimated by reversed‐phase liquid chromatography and feeding experiments with guppies (Poecilia reticulata). PDMS concentrations in fish were determined by capillary column gas chromatography and gas chromatography‐mass spectrometry. In contrast to polychlorinated biphenyls (PCBs), only very small amounts of PDMS were retained by the fish after six weeks feeding. 相似文献
The role of the peregrine falcon (Falco peregrinus) as a bioindicator for the accumulation of organohalogen compounds and other persistent organic pollutants has been established in field studies. Biometric indices for damage caused by pollutants such as the shell thickness and the shell index were determined and the egg contents were analyzed for various pollutants by gas chromatography/mass spectrometry. A wide range of chemically activated luciferase expression (CALUX®) bioassays were performed on subsamples of the eggs.
The following organohalogen compounds were found in the eggs of 2009: dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethane, heptachlor epoxide, hexachlorobenzene, dieldrin, hexachlorocyclohexane, polychlorobiphenyls and polychlorodibenzodioxins and polychlorodibenzofurans, polybromodiphenyl ethers, hexabromocyclododecane, tetrabromobisphenyl A, perfluoro compounds, and mercury. The DDT metabolite, dichlorodiphenyldichloroethene (DDE) (11,800 ng/g dry matter), was found to be the most highly concentrated egg contaminant followed by 2,2′,4,4′,5,5′-hexachlorobiphenyl (3800 ng/g). After a past general drop in pollution level, most egg contaminants presently plateau at levels that may still exceed limit values in foods of animal origin (DDE) or even toxicological thresholds (polychlorobiphenyls + polychlorodibenzodioxins, polybromodiphenyl ethers, perfluorooctanesulfonate, methylmercury).
Accumulation of DDE could be shown in peregrine falcon eggs from the uplands of Southwest Germany with elevations up to 1500 m, presumably due to its global distribution and its cold condensation in higher altitudes. In contrast, the concentration of polychlorobiphenyls in falcon eggs decreases with elevation, indicating that these pollutants originate mainly from conurbations and local industrial sites.
Significant negative correlations were found between both shell index and thickness and the concentration of Hg. A deleterious effect is also evident from a no-observed-adverse-effect level of 120 ng MeHg per gram egg determined by other authors in chronic feeding studies with ibises, which resulted in decreased egg productivity and male homosexual nesting and courtship behavior. The average Hg concentration in the peregrine falcon eggs from 2009 is almost four times higher than this level. MeHg accounted for 82.5% of the Hg present in the eggs of 2009 and 2010.
The cell test DR CALUX® for screening of dioxin-like activities can be used to detect not only the 29 regulated dioxin-like substances but also many other persistent organic pollutants with dioxin-like potencies, such as mixed halogenated dioxins/biphenyls. In our case, the results of bioanalytical screening methods showed no additional effect of other compounds with dioxin-like activity.
Ninety-three out of 177 analytes sought could be detected in the eggs. Chlorinated paraffins, organotin compounds, some pesticides that are still in use, and phthalic esters with the exception of traces of diethylhexyl phthalate could be excluded. All pollutants found in the eggs belong to substance classes banned by the Stockholm and Minamata Conventions. 相似文献