摘要:

AbstractAgricultural use of pesticides has remained high for economic reasons. Because aquatic species may bioaccumulate pesticides more readily than terrestrial organisms, there has been much concern about pesticides in agricultural runoff. Despite this concern, there presently is little relevant information for use in making accurate predictions of the impact of specific pesticide amounts in agricultural runoff on water quality at some point downstream. There is a compelling need for fundamental research on the physical, chemical, biological and hydrological processes that regulate pesticide behavior not only in agricultural and aquatic habitats, but also during transit between the two. Further, data are needed concerning pesticide toxicity potential as a function of the aquatic physical and chemical regime, and concerning population recovery dynamics as a function of pesticide concentration and species stress.

ISSN:0730-7268    

DOI:10.1002/etc.5620010402

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe acute toxicity of marine‐grade creosote, expressed as the 96‐h LC50, is 0.018 mg/L for mysids (Mysidopsis bahiaMolenock), 0.24 mg/L for pink shrimp (Penaeus duorarumBurken‐road) and 0.72 mg/L for sheepshead minnows (Cyprinodon variegatus, Lacépède). The 96‐h EC50(shell deposition) for Eastern oysters (Crassostrea virginicaGmelin) is 0.71 mg/L. Mysid bioassays and chemical analyses estimate the half‐life (≤ 1 week) for marine‐grade creos

ISSN:0730-7268    

DOI:10.1002/etc.5620010403

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractWater solubility, hydrolysis and photolysis rate constants, and sorption‐desorption partition coefficients were determined for lindane in three different natural water‐sediment systems, as well as in a Milli‐Q water and montmorillonite clay system. The aqueous solubility of lindane in surface waters at 25 ± 1°C ranged from 7.9 to 8.4 mg/L. In Milli‐Q water, lindane solubility was 9.2 mg/L. At α = 0.05, no significant difference was found between the values in different natural waters; however, the Milli‐Q water solubility did differ statistically. Lindane hydrolysis was found to be catalyzed by hydroxide and hydrogen ions. Neutral hydrolysis was relatively unimportant. Hydrolysis data followed first‐order kinetics withkhvalues of 74 × 10−4h−1at pH 9 and 7.4 × 10−1h−1at pH 5. Experimental hydrolysis half‐life (t1/2) in natural waters of pH 9.3 was comparable to the calculated value (92 h). Other natural water systems of pH 7.3 and 7.8 had t1/2values greater than calculated values. Adjusted mid‐winter photolysis half‐life of lindane in Milli‐Q water was 1.56 × 103h. Photolysis rate enhancement was noted in natural water of pH 9.3, possibly due to the alkaline hydrolysis side reaction. Photolysis rate retardation was noted in natural water of pH 7.3 and 7.8. Sorption‐desorption coefficient in Milli‐Q water‐montmorillonite clay was 1,259. Sorption coefficients for the natural systems ranged from 56 to 2,238. Results of the sorption‐desorption experiments indicate that the wide diversity of the characteristics of the natural water sediment systems considerably affect

ISSN:0730-7268    

DOI:10.1002/etc.5620010404

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractQuantitative ultrastructural studies were conducted on liver tissue from beach mice,Peromyscus polionotus, exposed to the toxin 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) in a field environment. Hepatic tissue from 30 animals was examined for changes in smooth endoplasmic reticulum, rough endoplasmic reticulum and mitochondria. Fifteen animals were collected from a unique military test site in northwest Florida, where they had been continuously exposed to soil levels of<10 to 710 parts per trillion (ppt) TCDD. The remaining animals were from a control field not exposed to TCDD. All tissue was examined both histopathologically and by an ultrastructural stereological technique.The mean levels of TCDD in composite liver samples from exposed mice collected in the field varied from 960 ppt for females to 1,300 ppt for males. The levels of TCDD in the livers of the beach mice collected from the field substantiated the bioaccumulation of TCDD. Although the levels of TCDD in the livers were greater than those found in the soil, TCDD was not detected in the portion of the food chain consisting of seeds.No significant histopathological or ultrastructural changes were found in hepatic parenchymal cells after long‐term, low‐level exposure to TCDD in the field. The levels of TCDD encountered in this study, though much lower than those normally found in most laboratory experiments, are far greater than the estimated concentrations in the environment, or in animal tissues after normal application of the herbicid

ISSN:0730-7268    

DOI:10.1002/etc.5620010405

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe accumulation of organic residues in fish is the result of competing rates of uptake and elimination, which can be modeled by pharmacokinetic techniques. Although first‐order kinetics are usually assumed, they are rarely verified. Models with biphasic, second‐order or Michaelis‐Menten kinetics may prove to be better choices, depending on exposure level and mode of elimination. The well‐known correlation between bioconcentration factor and partition coefficient (P) derives from separate correlations for the uptake and elimination rate constants with P. While such correlations appear to be linear in the range of log P = 2–5 for organics that are not metabolized, they sometimes fail at higher values of log P. A drug transport model is proposed to account for the “non‐ideal” bioconcentration of a variety of organics in fish. According to this model, uptake is a nonlinear function of partition coefficient, water solubility and membra

ISSN:0730-7268    

DOI:10.1002/etc.5620010406

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe most recent U.S. EPA water quality criteria indicate that chronic exposures to pulses of the LC50concentration of a metal will cause no damage to freshwater animals as long as the average daily concentration does not exceed the chronic, no‐observable‐effect concentration. We have tested this concept by exposingDaphnia pulexto such pulses of copper and cadmium. The exposures to cadmium for periods of up to 70d, caused no adverse effects. However, 70‐d exposures to daily pulses of copper resulted in significant reductions in survival, growth and reproduction. Although the two‐number criterion has not been tested for other chemicals, it is probable that the success of this approach in protecting freshwater animals from chronic exposures to chemicals will be as variable among other chemicals as we have shown it to be between copper and

ISSN:0730-7268    

DOI:10.1002/etc.5620010407

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractBrain cholinesterase (ChE) activity has been used extensively to monitor exposure to organophosphorus (OP) and carbamate (CB) insecticides in wild birds. A series of factorial experiments was conducted to assess the extent to which noncontaminant‐related environmental conditions might affect brain ChE activity and thereby confound the diagnosis of OP and CB intoxication. Underfeeding (restricting intake to 50% of control for 21 d or fasting for 1–3 d) or exposure to elevated temperature (36 ± 1°C for 1 d) caused only slightreductions (10–17%)in brain AChE activity in adult male Japanese quail (Coturnix coturnix japonica). This degree of “reduction” in brain AChE activity is considerably less than the 50% “inhibition” criterion employed in the diagnosis of insecticide‐induced mortality, but nevertheless approaches the 20% “inhibition” level used as a conservative estimate of sublethal exposure to a known in

ISSN:0730-7268    

DOI:10.1002/etc.5620010408

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractDipropylene glycol dibenzoate (Benzoflex® 9–88) (C20H22O5) is a primary plasticizer. It has a low order of toxicity, is biodegradable and is rapidly eliminated by mammals. The effect of Benzoflex 9–88 on microbial functions was mixed (cellulose degradation, urea degradation and sulfate reduction). Its octanol‐water partition coefficient is 455 ± 15. It was not mutagenic in the Ames test and theSaccharomy

ISSN:0730-7268    

DOI:10.1002/etc.5620010409

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe relationship of the acute LC50of chemicals to their chronic toxicity for aquatic animals can be expressed as the acute chronic ratio (ACR). Based on ACR data accumulated from the literature, the size ranges of ACRs for various chemicals were determined for different species. The relationship and significance of the size of the ACR for various species, LC50values, bioconcentration factors, classes of chemicals and their uses and mode of toxic action are given. Eighty‐six percent of the LC50acute toxicity data were less than two orders of magnitude different from the chronic toxicity no‐effect concentration for the same chemicals and species. Among the industrial organic chemicals (i.e., excluding pesticides and metals) the average ACR for four species of organisms was 12. Ninety‐three percent of these ACR values were 25 or below. Industrial organic chemicals have a higher percentage of ACR values below 25 do than pesticides and heavy metals. These data offer a statistical basis for the prediction of chronic toxicity from acute tox

ISSN:0730-7268    

DOI:10.1002/etc.5620010410

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

ISSN:0730-7268    

DOI:10.1002/etc.5620010401

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY