Pesticides monitoring journal最新文献

An overview of available literature indicates that dieldrin residues are still found routinely in soil, air, water, and food, despite the 1974 U.S. Environmental Protection Agency ban on the use of aldrin and dieldrin. Dieldrin residue levels in environmental substrates, which are indicative of aldrin or dieldrin use, have decreased significantly since the mid-1960s, the peak usage years. However, human tissue studies do not show a corresponding decline in dieldrin residue levels. Thirteen studies, conducted between 1963 and 1976, show that average dieldrin levels in human adipose tissue and human milk fat remain between 0.160 ppm and 0.220 ppm. Other studies suggest that an equilibrium exists in the distribution of dieldrin among various tissues in humans, including blood, fat, brain, and liver. This relationship indicates that the concentration of dieldrin in any tissue may be used as an index of total body burden. Thus it appears that the concentration of dieldrin in the human body has reached a constant level at which the amount ingested and absorbed equals the amount metabolized and excreted. The mechanism of the stable concentrations is unknown, as are the possible health effects of chronic, low-level exposure to dieldrin.

During the 1978 irrigation season, 14 ground water samples were collected in the Central Platte region of Nebraska, an area known to have high nitrate-nitrogen (NO3--N) levels, and analyzed for the presence of 13 pesticide residues. Atrazine levels ranged from 0.06 microgram/liter to 3.12 microgram/liter and were correlated to NO3--N concentrations with a coefficient of r = +0.55. Nitrate-nitrogen concentrations were measured as indicators of deep percolation from irrigated lands and ranged from 17.1 mg/liter to 34.3 mg/liter. Alachlor levels ranged from less than 0.01 microgram/liter to 0.71 microgram/liter. The amounts of 2,4-D were indeterminate because of experimental problems. Levels of the herbicides silvex and EPTC were below the limits of detectability. Levels of the organochlorine insecticides endrin, gamma-BHC (lindane), dieldrin, DDT and its primary metabolite DDE, heptachlor and its primary derivative heptachlor epoxide, and methoxychlor were all below the detectable limits of 0.005-0.010 microgram/liter.

Organochlorine residues were analyzed in blubber, brain, or muscle tissues of 69 individuals representing 10 species of small cetaceans. Collections were made from November 1968 through June 1976 at localities in the Eastern Tropical Pacific and along the coasts of California, Hawaii, Japan, and Uruguay, Relations of residue concentrations between tissues are described for DDE and PCBs in two dolphin species. sigma DDT and PCB residues in blubber of most of the 19 individuals of the five southern California species sampled exceed concentrations that are associated with reproductive impairment in pinnipeds, although the nature of such associations is not well defined. The sigma DDT residue of 2,695 ppm in blubber of one California coastal Tursiops truncatus is one of the highest concentrations reported in tissues of members of any population of wild mammals. Except for one rough-toothed dolphin (Steno bredanensis) from Maui, Hawaii, all individuals from all localities surveyed were contaminated with organochlorine compounds. Seventeen different organochlorines were detected; greatest diversity occurred near Japan and California. This is the first report of several of these compounds in tissues of any species of marine mammals. The o,p'-isomers and metabolites of DDT were detected unusually frequently. Ratios of p,p'-DDT to p,p'-DDE in blubber of cetaceans from waters off countries where use of this pesticide has been relatively recent and ongoing were at least an order of magnitude higher than in cetaceans from United States waters.

Organochlorine and heavy metal residues were determined in 103 shorebirds of seven species collected at Corpus Christi, Texas, during the winter of 1976-77 to evaluate their potential effects on population survival, DDE and polychlorinated biphenyls (PCBs) were detected in most samples. Chlordane isomers, dieldrin, toxaphene, and heptachlor epoxide also occurred, but less frequently. In general, organochlorine residues were low in skinned carcasses. Geometric means on a wet weight basis ranged from 0.25 ppm to 4.76 ppm for DDE and from 0.67 ppm to 6.64 ppm for PCBs; residues of the other compounds averaged less than 1 ppm in all instances. Mercury, lead, arsenic and vanadium occurred in all shorebird livers, and selenium and cadmium were detected in all kidneys. Residues of these metals, except selenium, were low in most tissue samples. Selenium averages varied from 1.77 ppm to 5.62 ppm (wet weight) in kidneys; residues in this range may be sufficient to inhibit reproduction or to induce other forms of toxicity, especially at the higher levels.

Ninety-nine soil samples from the rice-growing states of Arkansas, California, Louisiana, Mississippi, and Texas were collected, primarily to monitor the herbicide propanil. No residual concentrations of propanil were detected in any of these samples, but TCAB, a propanil transformation product, was detected in six samples at concentrations ranging from 0.01 ppm to 0.05 ppm. Organochlorine and organphosphorus pesticide determinations were also performed. The compounds dieldrin, aldrin, and DDT and its metabolites were found more frequently; endrin and chlordane were found less frequently. The organophosphorus pesticides diazinon and parathion were detected occasionally.

Organochlorine residues were determined in human milk samples from an agricultural area of Slavonia, Yugoslavia. Concentrations of pentachlorobenzene, hexachlorobenzene, alpha-, beta-, gamma-isomers of benzene hexachloride, heptachlor, aldrin, DDE, TDE, and DDT were determined by gas chromatography (GC). Confirmation was carried out by computerized GC-mass spectrometry. The most abundant contaminant was p,p'-DDE (range, 42.0-418.5 microgram/kg (ppb)).

Fifty-two female American shad (Alosa sapidissima) were collected during the spring of 1977 at two sites on the lower Hudson River, 27 miles and 75 miles from the river mouth. The fish were extracted with hexane, and the extracts were analyzed by electron-capture gas chromatography (EC-GC) and by GC/mass spectrometry (MS), PCBs were quantitated by EC-GC, and the concentrations were compared by fish length and by site. Fish collected from the downstream site contained a mean PCB concentration of 2.0 +/- 1.0 microgram/g, wet weight; fish from the upstream site contained a mean PCB concentration of 6.1 +/- 2.6 microgram/g, wet weight. Aliquots of the hexane extracts were fractionated before analysis by GC/MS. The presence of PCBs was confirmed, and DDE and the alkane series from C22 through C26 were detected. American shad are saltwater fish that only enter fresh water to spawn. Because they do not feed in fresh water before spawning, they may be used as an indicator of water contamination.

Eggs from nine clutches of loggerhead turtles (Caretta caretta) and two clutches of green turtles (Chelonia mydas) were collected as they were laid on Merritt Island, Florida. Eggs were incubated, frozen, and analyzed for organochlorines. Levels of DDE and PCB, the major contaminants, averaged less than 0.08 ppm in loggerhead eggs and were even lower in green turtle eggs. These concentrations are far below levels thought to be potentially harmful. Loggerhead eggs were frozen after 43-52 days incubation; both DDE and PCB declined significantly during this interval. Authors estimate that DDE averaged about 0.2 ppm in loggerhead eggs when they were laid. DDE levels in eggs of both turtle species were less than levels in eggs of crocodiles (Crocodylus acutus) from Everglades National Park and in eggs of 13 species of aquatic birds nesting on Merritt Island. The remarkably low residues in the turtle eggs probably indicate that, when not nesting, the turtles live and feed in areas remote from Florida.

Soil, corn plants, and foliage from areas surrounding two electrical salvage companies involved in reconditioning old transformers had unusually high levels of polychlorinated biphenyls (PCBs). Levels decreased as distance from the factories increased. PCBs were dispersed into the air through incineration of waste oils; water and soil contamination was caused by runoff from the factories. PCBs found in the contaminated areas closely resembled Aroclor 1260 as did the PCBs in the waste oil, whereas PCBs in other areas were more similar to Aroclor 1254. PCBs on surface soils taken from an unplowed pasture near the factories also resembled Aroclor 1260, whereas samples taken from depths of 2-4 inches showed degradation of some PCB isomers. PCB concentrations in corn cobs and kernels were < 0.05 ppm, whereas leaves contained PCB levels of up to 2.2 ppm. PCB levels in earthworms and small rodents collected near the factories were considerably higher than levels in the same types of animals collected from other areas.

Residues of acephate and its toxic metabolite methamidophos, attributable to the State-Federal program for eradication of the citrus blackfly (CBF) [Aleurocanthus woglumi Ashby] on citrus foliage, were assessed in urban areas in Pompano Beach, Florida. Eighteen dooryard citrus trees were sampled on two line transects, each ca 1.6 km long, along two city streets. The trees were sampled twice monthly for five months, beginning before chemical treatments were applied, continuing through the acephate treatment period, and ending when residues decreased below the limits of detection. Acephate and methamidophos residues, as high as 302.5 ppm and 15.8 ppm, respectively, were detected on leaves within one day after the first of a series of three treatments. Significant conversion of acephate to methamidophose was observed. Of the 143 samples collected, 114 contained measurable residues of both compounds; methamidophos accounted for an average of 19 percent of the total residues. Both compounds degraded rapidly, however, and residues averaged below 1 ppm approximately four weeks after the third treatment in the series. Average foliar half-lives for acephate and methamidophos were 8.93 days (SD = 2.52) and 8.40 days (SD = 2.55), respectively.