摘要:

AbstractThe effects of dissolved organic carbon (DOC) in the form of Aldrich humic acid on the accumulation and acute toxicities of three synthetic pyrethroids — fenvalerate, deltamethrin, and cyhalothrin—toDaphnia magnain laboratory experiments were investigated. Concentrations of DOC as low as 2.6 mg/L, 3.2 mg/L, and 3.1 mg/L for deltamethrin, fenvalerate, and cyhalothrin, respectively, resulted in a significant decrease in bioaccumulation. Acute toxicities of all three pyrethroids were found to decrease as DOC concentrations increased; e.g., at a DOC concentration of 15.5 mg/L, the acute toxicity of fenvalerate was reduced by a factor of 17. The percentages of deltamethrin and fenvalerate bound to DOC increased as DOC concentrations increased after 2‐h and 24‐h contact times. At low concentrations of DOC (e.g., 1.7 mg/L), as much as 40% of fenvalerate and 20% of deltamethrin were found sorbed to the dissolved material. After 24‐h contact times, 76.4 and 80.8% of fenvalerate and deltamethrin, respectively, were bound to DOC. Reverse‐phase partition coefficients (Krp) for both fenvalerate and deltamethrin were found to vary with DOC concentrations and were in the range 1.0 to 4.8 × 105L/kg for fenvalerate and 0.9 to 5.6 × 105L/kg for

ISSN:0730-7268    

DOI:10.1002/etc.5620100111

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractAerial drift from pesticide spray applications can result in contamination of nontarget environments such as aquatic systems. In this study, the off‐target deposit of aerially applied endosulfan was collected on flat plate samplers and in containers of water placed at various distances downwind of the treated area. The water contaminated by that deposit was subsequently used to conduct 24‐h lethal bioassays in a nearby temporary laboratory, using threespine stickleback (Gasterosteus aculeatus), water boatmen (Sigara alternata), caddisfly larvae (Limnephilus spp.), bivalve molluscs (Pisidium spp.), bloodworms (Chironomiidae spp.), and water fleas (Daphnia magna). Three different spray events were sampled, all of which occurred at times when meteorological conditions were within regulatory constraints. Chemical analysis of deposit collectors and exposed water indicated that deposit decreased in an exponential manner with distance downwind and ranged from 82 mg/m3and 1.7 mg/L for plates and waters within the target site to 0.051 mg/m3and 0.004 mg/L for plates and waters at 200 m downwind. After 24‐h exposure to spray‐drift contaminated water, no mortalities that could be attributed to the pesticide were observed for bivalve molluscs, bloodworms, or water fleas, even within the treated area. Water boatmen, caddisfly larvae, and threespine stickleback, on the other hand, suffered levels of mortality that varied directly with distance downwind from the treated area. The distances at which 50% mortality was measured in water boatmen and caddisfly larvae tests were 50 m and 10 m, respectively. Threespine stickleback were the most sensitive species tested, having a mortality of up to 90% at a distance of 200 m downwind. These results demonstrate the extreme risk to aquatic organisms from drift deposit of aerially applied endosulfan and indicate the need for similar assessments of other popular pes

ISSN:0730-7268    

DOI:10.1002/etc.5620100112

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe respiratory‐cardiovascular responses of spinally transected rainbow trout to acutely lethal concentrations of chlorpyrifos, cypermethrin, fenvalerate, endosulfan, endrin, and strychnine were examined. Common to all six toxicants, the most striking change in respiratory‐cardiovascular parameters was an increased cough frequency. Ventilation frequency and volume dropped in strychnine‐exposed trout, but both remained near predose levels (frequency) or elevated (volume) in the pyrethroid‐ and cyclodiene‐exposed trout. In chlorpyrifos‐intoxicated trout, ventilation frequency decreased while volume increased. Oxygen consumption remained near predose levels in the chlorpyrifos‐, pyrethroid‐, and strychnine‐exposed trout, but increased dramatically in the cyclodiene‐exposed trout. Arterial oxygen, carbon dioxide, and pH declined in all the toxicant groups. In the pyrethroid‐ and strychnine‐exposed trout, hematocrit and hemoglobin levels tended to increase or remain constant during intoxication. Conversely, in the chlorpyrifos‐ and cyclodiene‐exposed trout, values for these parameters decreased. The responses for these pesticides (N= 23 fish) were combined with five fish acute toxicity syndromes (FATS) (N= 52 fish) previously described (non‐polar narcosis syndrome, polar narcosis syndrome, acetylcholinesterase inhibitor syndrome, respiratory uncoupler syndrome, and respiratory irritant syndrome) and assessed using discriminant function analyses. The final analysis resulted in 93% correc

ISSN:0730-7268    

DOI:10.1002/etc.5620100113

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

ISSN:0730-7268    

DOI:10.1002/etc.5620100114

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY