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1.
In May 1972, 0.309 ppm methoxychlor black fly larvicide was applied in a single test on the North Saskatchewan River. Eight to nine days later residues of 0.05-0.10 ppm methoxychlor occurred in sand 21-22 km downstream from the point of injection. Methoxychlor was not detected in water, insect larvae, shellfish, or muscle tissues of three fish species on the same sampling date. Perhaps because of relatively high oil content in goldeye fish, methoxychlor residues in muscle tissues were 1.0-1.5 ppm in 8 percent of those sampled, 0.21-0.99 in 21 percent, and 0.02-0.20 in 37 percent. In 34 percent of the goldeye fish no residues were detected. Goldeye and other fish collected before or 17 weeks after this injection did not contain detectable levels of methoxychlor. River water in two samples of the injected slug of water collected 6.5 km downstream from the point of injection contained 0.14 and 0.16 ppm methoxychlor. The suspended solids filtered from these sample contained 40 and 47 percent of this methoxychlor (437 and 892 ppm, respectively). Thus methoxychlor may act selectively against filter-feeding species, especially black fly larvae. 相似文献
2.
As part of the National Pesticide Monitoring Program, the U.S. Fish and Wildlife Service analyzed organochlorine contaminant residues in fish samples collected from about 100 stations each year from 1970 to 1974. During this period, mean residues of DDT and its metabolites declined nationally but remained widespread, and high concentrations continued to be present in areas where DDT use was extensive. Results of interlaboratory crosscheck analyses supported these conclusions, despite interpretation problems posed by intercompound analytical interferences in 1970 and 1971. Temporal trends in PCB residues were less obvious. Highest PCB residues were found in the industrialized areas of the Northwest and Midwest, and traces were present at most stations. Dieldrin and endrin residues remained essentially unchanged during this period; dieldrin residues were widespread and were highest in Hawaii and in areas of the Midwest where aldrin was used extensively. Toxaphene occurrence increased; it was formerly found only in fish from streams draining cotton-farming regions, but residues were detected in 1974 samples from other areas. According to the recommendation of the National Academy of Sciences' Water Quality Criteria, organochlorine residues in freshwater fish may have represented a hazard to piscivorous fish and wildlife at 71 percent of the stations sampled in 1970 and 66 percent in 1974. 相似文献
3.
Various components of the aquatic ecosystem of Tuttle Creek Reservoir on the Big Blue River in northeastern Kansas were examined for organochlorine insecticide residues in 1970-71. Components examined were water, sediments, periphyton, zooplankton, insects, and whole-body samples of 10 common fish species. Only dieldrin and sigmaDDT residues were detected. Dieldrin was found in part of the nonfish samples at levels ranging up to 0.01 ppm and in 97 percent of the fish samples with a high level of 0.17 ppm. SigmaDDT residues were also detected in part of the nonfish samples at levels ranging up to 0.42 ppm, and in 98 percent of the fish samples at levels as high as 0.57 ppm. Authors' findings are roughly similar to those of other surveys of Kansas fishes. All levels are relatively low compared with those reported in surveys from other parts of the Nation. 相似文献
4.
Pesticides and heavy metals were monitored in fish collected from 11 estuaries representing all the Atlantic drainage basins in Georgia and South Carolina. Part of the U.S. Environmental Protection Agency National Estuarine Monitoring Program, the semianual survey of young-of-the-year fishes, was conducted from 1972 to 1974. Data are intended to provide an initial base line for residue levels in the fish studied in these waters. Dieldrin was found in 2 percent of the samples, DDT and metabolites were in 33 percent, polychlorinated biphenyls were in 4 percent, and mercury was in 47 percent. Noticeably absent were any measurable residues of toxaphene even though there is a toxaphene manufacturing plant in Brunswick, Ga. 相似文献
5.
本研究探讨了温室和田间试验条件下西兰花植株残体还田对棉花黄萎病的防治效果以及西兰花残体对棉花生长的安全性,以期为深入研究西兰花植株残体对棉花黄萎病的生态防治机制提供依据。将粉碎的西兰花植株残体与培养基质分别按1%、3%、5%、7%和14%处理混匀,在（28±2）℃条件下分别腐解7和30 d后种植棉花,测定其对棉花出苗率、株高的影响以及对黄萎病的防治效果。研究结果表明,当腐解时间为7 d,西兰花残体处理比例为1%和3%时,棉花出苗率与不添加西兰花残体的空白对照处理不存在显著差异,但对株高具有显著促生长作用,增幅分别为19.46%、42.41%和36.96%;西兰花残体添加比例为5%、7%和14%时,对出苗具有不同程度的抑制作用。当腐解时间为30 d时,上述各比例西兰花残体处理后的棉花出苗率和株高与空白对照之间差异不显著。西兰花残体处理显著降低了棉花黄萎病的发病率和病情指数,其21 d后的防治效果达到72.55%。田间试验表明,西兰花残体在棉花全生育期内对黄萎病的防治效果为43.06%。综合分析表明,西兰花残体的施入,促进了棉花生长,降低了黄萎病的发病率和病情指数,且在发病初期的防治效果优于后期。研究结果为深入研究西兰花残体防治棉花黄萎病的生态机制提供理论依据和技术指导,最终为棉花黄萎病的绿色防控和化学农药的减量提供了新途径和思路。 相似文献
6.
甲拌磷在棉花及土壤中的残留动态研究 总被引：5，自引：0，他引：5
本文采用气相色谱法测定了甲拌磷在棉花叶片、棉籽和土壤中的消解动态及最终残留量.结果表明甲拌磷在土壤中的半衰期为8.3～10.8d,在棉花中的半衰期为6.6～7.3d,甲拌磷在碱性土壤中的降解速度比在酸性土壤中快.最终残留测定结果说明,甲拌磷在棉籽中未检出. 相似文献
7.
This report summarizes 1524 analyses of juvenile fish collected semiannually in 144 estuaries nationwide from July 1972 through June 1976. Pooled samples of 25 whole fish were screened for 20 common pesticides and polychlorinated biphenyls (PCBs). The three most common residues, DDT, PCBs, and dieldrin, were found in 39, 22, and 5 percent of the samples, respectively. Data indicate that estuarine pollution levels continue to decline. 相似文献
8.
R Frank M Holdrinet H E Braun D P Dodge G E Sprangler 《Pesticides monitoring journal》1978,12(2):60-68
Five species of fish from Lake Superior and 12 species from Lake Huron were analyzed for organochlorine pesticides and polychlorinated biphenyls (PCBs) between 1968 and 1975. Mean residues of sigma DDT peaked at 1.72 ppm and 7.60 ppm in lake trout (Salvelinus namaycush) from Lakes Superior and Huron, respectively. By 1975, the mean level of sigma DDT had decreased in lake trout and was highest in bloaters (Coregonus hoi) from both lakes: 1.06 ppm and 1.87 ppm, respectively. Dieldrin levels in fish from Lake Superior changed little over the same period. However, in 1969-70, dieldrin levels in fish from Lake Huron exceeded the 0.3 ppm tolerance level set by Health and Welfare Canada or the Food and Drug Administration, U.S. Department of Health, Education, and Welfare in 5 percent of lake whitefish (Coregonus clupeaformis) and 10 percent of bloaters. By 1975, 50 percent of bloaters caught in Georgian Bay and North Channel had dieldrin levels above 0.3 ppm. PCB residues declined in lake trout and lake whitefish caught in Lake Superior between 1971 and 1975, but increased slightly in bloaters and white sucker (Catostomus commersoni). Mean PCB residues in bloaters caught in Lake Huron in 1969-71 and 1975-76, and splake (Salvelinus fontinalis and S. namaycush) and cisco (Coregonus artedii) caught in 1975 exceeded the 2 ppm tolerance level. 相似文献
9.
由大丽轮枝菌引起的棉花黄萎病是一种难以防治的土传病害,西兰花残体还对其有一定的防治作用,防效为62.82%。为解析西兰花残体对棉花黄萎病的防治机制,本研究通过土壤杆菌转化的方法构建了大丽轮枝菌的绿色荧光标记菌株,采用共聚焦显微镜观察标记菌株在添加西兰花残体营养基质中和空白对照营养基质种植的棉花体内的侵染和扩展情况。结果表明构建的标记菌株gfp-wx-1与野生菌株wx-1的生物学特性无显著性差异。同时发现大丽轮枝菌在添加西兰花残体营养基质中棉花体内扩展较慢,具体表现为:在空白营养基质种植的棉花体内,大丽轮枝菌在接种第2 d时就可侵染根尖表层及根内部,第3 d到达茎部维管束,第5 d叶片可观察到少量病原菌,第7 d第一片子叶呈现大量病原菌,后期迅速扩展,叶片出现黄萎病斑;而在营养基质中添加西兰花残体种植的棉花体内,大丽轮枝菌在接种第2 d时就可侵染根尖表层,第3 d侵染根尖内部,第5 d侵染茎部维管束,直到第7 d第一片子叶才出现少量病原菌,后期扩展慢,叶片病斑较少。本研究通过荧光定量PCR方法检测了大丽轮枝菌在两个处理棉花根部定殖情况,结果表明西兰花残体能够显著降低大丽轮枝菌在棉花根部定殖的量。该研究初步明确了西兰花残体对棉花黄萎病的防治机制,为棉花黄萎病的绿色防治提供了一条新的途径。 相似文献
10.
由大丽轮枝菌引起的棉花黄萎病是一种难以防治的土传病害,西兰花残体还对其有一定的防治作用,防效为62.82%。为解析西兰花残体对棉花黄萎病的防治机制,本研究通过土壤杆菌转化的方法构建了大丽轮枝菌的绿色荧光标记菌株,采用共聚焦显微镜观察标记菌株在添加西兰花残体营养基质中和空白对照营养基质种植的棉花体内的侵染和扩展情况。结果表明构建的标记菌株gfp-wx-1与野生菌株wx-1的生物学特性无显著性差异。同时发现大丽轮枝菌在添加西兰花残体营养基质中棉花体内扩展较慢,具体表现为:在空白营养基质种植的棉花体内,大丽轮枝菌在接种第2 d时就可侵染根尖表层及根内部,第3 d到达茎部维管束,第5 d叶片可观察到少量病原菌,第7 d第一片子叶呈现大量病原菌,后期迅速扩展,叶片出现黄萎病斑;而在营养基质中添加西兰花残体种植的棉花体内,大丽轮枝菌在接种第2 d时就可侵染根尖表层,第3 d侵染根尖内部,第5 d侵染茎部维管束,直到第7 d第一片子叶才出现少量病原菌,后期扩展慢,叶片病斑较少。本研究通过荧光定量PCR方法检测了大丽轮枝菌在两个处理棉花根部定殖情况,结果表明西兰花残体能够显著降低大丽轮枝菌在棉花根部定殖的量。该研究初步明确了西兰花残体对棉花黄萎病的防治机制,为棉花黄萎病的绿色防治提供了一条新的途径。 相似文献
11.
棉铃疫菌的越冬存活 总被引：9，自引：0，他引：9
用MTT活体染色法,对棉铃疫苗(Phytophthora boehmeriae Sawada)的存活越冬进行了研究,结果表明:孢子囊和卵孢子均可在棉田土中的病残体(烂钤壳,棉籽)上存活。其中孢子囊可存活3~4个月,且其存活率可高达58.0%,认为孢子囊在棉铃疫病的再侵染过程中起重要作用。但孢子囊在1月份温度达零度时就全部死亡,不能越冬。而卵孢子在历经1990年至1991年冬季零度以下76天(其中最低温度达-2.8℃)后仍可以存活,在存活300天以后其存活率达48.8%,证明卵孢子是毫无疑问的越冬菌态。生物测定,越冬后卵孢子形态观察,卵孢子萌动变化与温度的关系表明,越冬存活的卵孢子可以成为棉铃疫病的初侵染来源。 相似文献
12.
The residual effect of a dried methanolic extract of neem (Azadirachta indica A. Juss) seed kernels was investigated with larvae of the Egyptian cotton leafworm,Spodoptera littoralis (Boisd.), in field trials. Fodder beet was sprayed with 1% emulsions of the extract. The treated leaves were collected from the field 1, 3, 5 and 9 days after spraying and offered to the larvae for 48 h. Survival and mean weight of the larvae were recorded 2, 4, 6, 9 and 11 days from the start of exposure to the residues, and rate of pupation was calculated. The extract had a strong antifeedant effect and an intense insect growth-regulating (IGR) effect in field-treated leaves, especially with the 1- and 3-day-old residues. A positive correlation was found between the age of the residues and the mean percent of live larvae, larval weight and pupation rate of the larvae. 相似文献
13.
涕灭威在棉籽和土壤中的残留研究 总被引：2，自引：0，他引：2
采用气相色谱火焰光度检测器测定了涕灭威及其有毒代谢物在棉籽和土壤中的残留,并对文献报道的方法作了改进。该方法的回收率为85—105％。在棉籽和土壤中的最小检测量分别为0.006ppm和0.004ppm。两年内在8个地区进行涕灭威在棉花上的田间和小区试验结果表明,涕灭威主要滞留在0—10cm的土壤中,最高检出量为0.039ppm,而残留量与施药量呈正相关;在施药量大于1.2kg/ha时,棉籽中有涕灭威检出,平均检出量为0.023ppm,最高检出量为0.035ppm。 相似文献
14.
Replicated field plot trials were carried out to evaluate the role of fish as biocontrol agents of insect pests of rice in the Philippines. Evidence from suction sampling, examination of fish gut contents, and rice plant damage assessment strongly suggest that Common Carp Cyprinus carpio (L.) and Nile Tilapia Oreochromis niloticus (L.) do significantly reduce the densities of stemboring moths and chironomid midges, while the abundance levels of other arthropods are not significantly affected. This impact by fish often was more important in the wet season when heavy rains and wind likely caused the arthropods to become dislodged from the plant and fall onto the water. Predation by fish was particularly evident during the first 45 days of the crop during the wet season when adult chironomid midge abundance was high. The fish gut content analysis revealed that all insect guilds are represented in the diet of both of the fish species regardless of whether the life-cycle of the arthropod prey is aquatic, semi-terrestrial, or terrestrial. Thus, fish in rice fields are part of the assemblage of natural enemies of rice pests. While fish alone cannot completely suppress rice pest populations below the economic threshold, their significant contribution should not be overlooked. 相似文献
15.
Twenty-six composite samples of fish were collected during 1978 from United States watersheds near the Great Lakes and analyzed for polychlorinated biphenyls (PCBs) and related organic chemicals. PCB mixtures resembling Aroclor 1254 were found in all samples, and mixtures resembling Aroclor 1242 (or 1016) were found in 77 percent of the samples. Total PCB concentrations in the whole-fish composite samples ranged from 0.13 to 14.6 ppm; 65 percent of the samples contained more than 2 ppm PCBs. DDT and its metabolites were found in all samples. sigma DDT concentration was 1.66 ppm, and 81 percent of the samples contained less than 1.0 ppm sigma DDT. Chlordane ranged from less than 0.001 to 2.57 ppm in 38 percent of the samples. Hexachlorobenzene was found in 65 percent of the samples, ranging from less than 0.005 to 0.447 ppm. Other chemicals identified by gas chromatography/mass spectrometry included petroleum hydrocarbons and chlorobenzenes, chlorostyrenes, chlorophenols, and chlorinated aliphatic compounds. Fish from the Ashtabula River (Ohio), Rock River (Ohio), and Wabash River (Indiana) contained extremely complex residues of chlorinated and other organic chemicals. 相似文献
16.
Indoxacarb is a new oxadiazine insecticide that has shown outstanding field insecticidal activity. The toxicity of a 145 g litre-1 indoxacarb SC formulation (Steward) was studied on the tarnished plant bug Lygus lineolaris and the big-eyed bug Geocoris punctipes. Both insect species responded very similarly to indoxacarb in topical, tarsal contact and plant feeding toxicity studies. The topical LD50 of the formulation was c 35 ng AI per insect for both species. Prolonged tarsal contact with dry indoxacarb residues did not result in mortality for either insect species. However, both species were susceptible to feeding through dried residues of indoxacarb after spraying on young cotton plants. Feeding on water-washed plants resulted in lower mortality than that observed with unwashed plants, and toxicity declined even more dramatically after a, detergent rinse, indicating that much of the indoxacarb probably resides on the cotton leaf surface or in the waxy cuticle. These results were corroborated by HPLC-mass spectrometry measurements of indoxacarb residues on the plants. Greater mortality for both species was observed in a higher relative humidity environment. Higher levels of accumulated indoxacarb and its active metabolite were detected in dead G punctipes than in L lineolaris after feeding on sprayed, unwashed plants. When female G punctipes ate indoxacarb-treated Heliothis zea eggs, there was significant toxicity. However, only c 15% of the females consumed indoxacarb-treated eggs, and the rest of the females showed a significant diminution of feeding in response to the insecticide. Cotton field studies have shown that indoxacarb treatments at labelled rates lead to a dramatic decline in L lineolaris, with negligible declines in beneficial populations. A major route of intoxication of L lineolaris in indoxacarb-treated cotton fields thus appears to be via oral, and not cuticular, uptake of residues from treated cotton plants. The mechanisms for selectivity/safety for G punctipes are currently under investigation and may be a combination of differential feeding behavior and diminution of feeding by females exposed to indoxacarb-treated eggs. 相似文献
17.
建立了超高效液相色谱-亲水色谱柱测定吡蚜酮在棉花和土壤中残留量的分析方法。样本在弱碱条件下采用分散固相萃取(QuEChERS)法进行前处理。结果表明:吡蚜酮在棉叶和棉籽中添加水平为0.05~0.50 mg/kg时,其平均回收率分别为76.9%~91.1%和76.4%~93.7%,相对标准偏差(RSD)为7.2%~8.2%和6.2%~9.8%;在土壤中添加水平为0.02~0.5 mg/kg时,平均回收率为83.8%~94.6%,RSD为5.3%~8.0%。在山东和河南两地按推荐剂量(有效成分30 g/hm2)和1.5倍推荐剂量(有效成分45 g/hm2)施用10%吡蚜酮·高效氯氟氰菊酯悬浮剂后4 d,吡蚜酮在土壤和棉叶中的残留量分别低于0.02和0.05 mg/kg;至收获时,其在土壤和棉籽中的最终残留量低于0.02和0.05 mg/kg。 相似文献
18.
Mercury, arsenic, and cadmium in fish, water, and sediment of American Falls Reservoir, Idaho, 1974.
Mercury and cadmium were found in fish, water, and sediment of American Falls Reservoir (AFR), Idaho. Mercury and cadmium levels in some fish exceeded human health standards set by the Food and Drug Administration, U.S. Department of Health, Education and Welfare, and the World Health Organization. Analyses performed on the flesh of rainbow trout showed mercury residues of up to 1.20 mg/kg, which were higher than residues previously reported in trout collected in 1970 and 1971 from AFR. Cadmium residue levels were as high as 0.80 mg/kg. Although arsenic was found in reservoir sediment at levels of 1.36-2.40 mg/kg, it was not detected in fish. 相似文献
19.
通过对新和县1999、2002两年冬季铲除田埂杂草带棉田棉花卷叶率变化情况的观测,研究铲除田埂杂草对棉砾的防治效果。结果表明:苗期、蕾期防治效果可以达到70%～90%,棉花卷叶率下降3.35～16.83倍(P<0.05)。棉蚜越冬和早春迁飞与田埂上的杂草有关可能是这项技术有效的原因。 相似文献
20.
彩色棉抗旱特性研究 总被引：2，自引：0，他引：2
在中等肥力条件下,通过不同的灌水量和灌水次数,以熟性相当的白色棉中熟品种作对照,考查两个彩色棉品种的抗旱性能。结果表明:灌水量不影响白色棉纤维的色泽度,但对彩色棉的色泽度有一定的影响,随着灌水量的减少,彩色棉纤维色泽度降低;灌水量对彩色棉和白色棉的纤维比强度、马克隆值都不产生明显的影响,但对纤维长度影响较大,尤其是少水处理(B2)的影响最大,其中少水处理(B2)和高水处理(CK)相比,A1、A2、A3三品种纤维长度分别减小0.8 mm、1.1 mm和0.9 mm;随着灌水量和灌水次数的减少,各品种生育期均相应提早,但对彩色棉生育进程的影响较小,其中少水处理(B2)与高水处理(B5)相比,两个彩色棉品种生育期分别较对照减少17d和16 d,而A3白色棉对比品种较对照减少20 d;随着灌水量和灌水次数的减少,各品种蕾铃脱落率增高,产量下降,但彩色棉两品种均较白色棉品种蕾铃脱落率低4.1%~7.0%,产量降幅小1.0%~10.9%,表现出较强的抗旱性能。 相似文献