Determination of a tolerable daily intake of DDT for consumers of DDT contaminated fish from the lower Yakima River, Washington

DDT, DDE, and DDD have been detected at elevated concentrations in sediments and fish of the Yakima River, its tributaries and drainages. An assessment was conducted to evaluate the public health significance of eating fish from the river. This was accomplished by establishing a daily intake level of DDT for the population of greatest concern, and comparing this level to a tolerable daily intake. The most sensitive and highly exposed group was determined to be breastfeeding infants. Infant daily intakes of DDT, based on estimated mother's DDT-breast milk levels, were compared to a recommended tolerable daily intake. Results indicate that mothers who frequently consume Yakima River bottom-feeding fish could have breast milk DDT concentrations sufficiently high to expose their infants to levels above the tolerable daily intake.

Arctic indigenous women consume greater than acceptable levels of organochlorines

Exposure to polychlorinated biphenyls and organochlorine pesticides through traditional food resources was examined for Arctic Indigenous women living in two cultural and environmental areas of the Canadian Arctic--one community representing Baffin Island Inuit in eastern Arctic and two communities representing Sahtú Dene/Métis in western Arctic. Polychlorinated biphenyls, toxaphene, chlorobenzenes, hexachlorocyclohexanes, dichlorodiphenyltrichloroethane, chlordane-related compounds and dieldrin were determined in local food resources as normally prepared and eaten. Quantified dietary recalls taken seasonally reflected normal consumption patterns of these food resources by women in three age groups: 20-40 y, 41-60 y and > or = 61 y. There was wide variation of intake of all organochlorine contaminants in both areas and among age groups for the Sahtú. Fifty percent of the intake recalls collected from the Baffin Inuit exceeded the acceptable daily intake for chlordane-related compounds and toxaphene, and a substantial percentage of the intake records for dieldrin and polychlorinated biphenyls exceeded the acceptable or tolerable daily intake levels. Primary contributing foods to organochlorine contaminants intake for the Baffin Inuit were meat and blubber of ringed seal, blubber of walrus and mattak and blubber of narwal. Important foods contributing organochlorine contaminant to the Sahtú Dene/Métis were caribou, whitefish, inconnu, trout and duck. The superior nutritional benefits and potential health risks of traditional food items are reviewed, as are implications for monitoring organochlorine contaminant contents of food, clinical symptoms and food use.

Sediment core versus grab samples: evaluation of contamination and toxicity at a DDT-contaminated site

Four sites from a stream system near Huntsville, Alabama, contaminated with DDT and its metabolites, were sampled using a coring device. Grab samples were also collected at these and five other sites. Analytical and toxicological evaluations were made on both sets of samples. Core samples provided vertical delineation of toxicity and contamination in sediments, and documented periods of sedimentation with clean material, which appears to be isolating the contaminated sediments from benthic communities. Grab samples yielded less information about the sites. Relationships between DDT concentration and sediment toxicity to Chironomus tentans were similar regardless of the sampling method. Substantial increases in toxicity occurred in most samples when concentrations exceeded 3000 micrograms of DDT residue/g organic carbon.

Effects of perinatal polychlorinated biphenyls and dichlorodiphenyl dichloroethene on later development

OBJECTIVE

Determining whether early developmental effects of perinatal exposure to polychlorinated biphenyls (PCBs) or dichlorodiphenyl dichloroethene (DDE) persist.

DESIGN

Cohort followed from birth; ages now 5 1/2 to 10 1/2 years.

SETTING

General community.

PARTICIPANTS

Volunteer sample of 859 children, of whom 712 had been examined with the McCarthy Scales of Children's Abilities at 3, 4, or 5 years; 506 sent report cards.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Neither transplacental nor breast-feeding exposure to PCBs or DDE affected McCarthy scores at 3, 4, or 5 years. There was no statistically significant relationship between poorer grades and PCB or DDE exposure by either route.

CONCLUSIONS

The deficits seen in these children on the Bayley Scales of Infant Development through 2 years of age are no longer apparent.

Factors affecting levels of DDT and metabolites in human breast milk from Kwazulu

Concentrations of p,p'-DDT, p,p'-DDE, and p,p'-DDD have been determined in breast milk of mothers residing in two different areas of KwaZulu. Annual intradomiciliary application of DDT was used for the interruption of malaria transmission in one area, while the other served as the control. Milk from mothers living in DDT-treated dwellings had significantly higher mean levels of DDT and metabolites (mean sigma DDT 15.83 mg kg-1 in milk fat) than those from the control area (0.69 mg kg-1). The highest recorded sigma DDT value was 59.3 mg kg-1 (milk fat). Primiparous mothers from the malarious area had significantly more sigma DDT and metabolites (sigma DDT 24.82 mg kg-1) than multiparous mothers from the same area (mean 12.21 mg kg-1). Parity was the best predictor of DDT in breast milk of the exposed group. The percentage DDT and the sigma DDT increased significantly with an increase in parity. The same, but not significant, trend was also found for the control group. It was hypothesized that the increase in percentage DDT that occurred with higher parities was due to the uptake of DDT and elimination via milk. This process was faster than the uptake and endogenous formation of DDE. Designing predictive models using multiple regression was not very successful. The recorded levels do not represent an appreciable health risk to the mothers. From the literature it was deduced that at the recorded levels, a well-founded risk to the infants, particularly the firstborns, exists in sprayed areas.

Levels of DDT and metabolites in breast milk from Kwa-Zulu mothers after DDT application for malaria control

Concentrations of DDT, DDE and DDD were determined in the breast milk of Kwa-Zulu mothers residing in two different areas--with and without annual intra-domiciliary applications of DDT for the interruption of malaria transmission (exposed and control groups, respectively). While no significant change in levels with time was found in the control group, both DDT and DDE in breast milk of the exposed group increased after DDT application and this continued for three more months, after which it did not decrease appreciably. Percentage DDT increased from 42.57% (sigma DDT = 12.21 mg/kg milk fat) before spraying to 50.87% (sigma DDT = 13.79 mg/kg milk fat) following DDT application. At 6 and 9 months after the application it was 45.85% (sigma DDT = 19.49 mg/kg milk fat) and 43.27% (sigma DDT = 18.34 mg/kg milk fat), respectively. These results suggest a risk to the health of the infants in the exposed group.

Characterization of new bacterial transformation products of 1,1,1-trichloro-2,2-bis-(4-chlorophenyl) ethane (DDT) by gas chromatography/mass spectrometry

The microbial transformation of DDT, DDD and DDE was studied in Gram-negative strain B-206 and a number of phenolic metabolites were identified as the trimethylsilyl derivatives in the bacterial extracts by gas chromatography/mass spectrometry. The major metabolites of DDT were DDD, DDE, DDMU, 1,1,1-trichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4'-chlorophenyl) ethane, 1,1,1-trichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4'-hydroxyphenyl) ethane, and 1,1,1-trichloro-2,2-bis-(2-hydroxy-4-chlorophenyl) ethane. Conversely, DDD was mainly degraded into DDE, 1,1-dichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4'-chlorophenyl) ethane and 1,1-dichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4'-hydroxyphenyl) ethane. Finally, DDE was transformed into DDMU, 1,1-dichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4'-chlorophenyl) ethylene, 1,1-dichloro-2-(2-hydroxy-4-chlorophenyl)-2-(4'hydroxyphenyl) ethylene and 1-chloro-2-(2-hydroxy-4-chlorophenyl)-2-(4'-chlorophenyl) ethylene. The phenolic metabolites exhibited [M - TMSCl]+., [M - HCl - TMSCl]+. and/or [M - HCl - TMSCl - Me]+ fragment ions which reflect the presence of an ortho hydroxyl group in these molecules. Other mass spectral features used to determine their structure are presented and a metabolic scheme accounting for their formation is proposed.

One-step extraction and cleanup procedure for determination of p,p'-DDT, p,p'-DDD, and p,p'-DDE in fish

A simplified method that combines extraction, partitioning, and cleanup in a single step for measuring p,p'-DDT and its metabolites in fish is described. Minced fish samples are emulsified with disodium hydrogen orthophosphate and trisodium citrate, ground with sodium sulfate, and eluted from a chromatographic column prepacked with alumina and silicic acid. The fats and fatty acids are solubilized and easily extracted from the tissues and retained by the column, while p,p'-DDT and its metabolites are quantitatively eluted with 40 mL n-hexane. The eluate is directly applied to a gas chromatographic column. Average recoveries of p,p'-DDT and its metabolites added to fish in vitro are 81%. The average coefficient of variation for recoveries of p,p'-DDT and its metabolites is less than 6.5% and the detection limit is 0.001 micrograms/g for p,p'-DDE, thus making this method very suitable for residue analysis.

[The enzymatic degradation of DDT. 5. Direct transformation of DDD (dichlorodiphenyldichloroethane) into an aldehyde]

The chemical-preparative preparation of the aldehyde (DDHO) is possible by using of saponification. Its enzymatic formation in the organism of warm-blooded animals has not been described up to now. The identification of the aldehyde after application of DDD to rats was successful, inspite of the inhibition of the HCl-cleaving consecutive reactions, whereby the enzymatic formation of the aldehyde was indicated. A possible reaction mechanism is presented.

[The contamination of human milk with chlororganic pesticides (author's transl)]

A survey on the situation concerning the residues on pesticides in human milk in West Germany is given, based on own investigations. Nearly the whole pattern of chlororganic pesticides - DDT with its metabolites DDE and DDD, hexachlorobenzene (HCB), the different isomeres (alpha-, beta-, gamma-) of benzenehexachloride (BHC) as well as dieldrin and heptachloroepoxid - together with polychlorinated biphenyls (PCB) coming from the environment - were found in all samples of human milk, though in different concentrations. PCB, HCB and beta-BHC had been discovered in human milk only about ten years ago. The residues have decreased in the past years. The concentrations are still so high that the amounts consumed by the suckling exceed the ADI values for the contaminants in question. But in the opinion of the experts the advantages connected with the alimentation with human milk weigh more than the eventual risk by the contamination.

WHO collaborative breast feeding study. I. Organochlorine contaminants in individual samples of Swedish human milk, 1978--1979

Individual samples of human milk collected in Uppsala at 3 months post-partum (18 samples) or 6 months post-partum (23 samples) were analysed for chlorinated insecticides and polychlorinated biphenyls (PCBs) by gas chromatography. The mean levels of the organochlorine compounds in the 3- and 6-month groups were similar. The mean content of DDE, the major metabolite of DDT, in all the samples was 54 micrograms/kg fresh weight (1.3 mg/kg on a fat basis) with a range of 8.4--220 micrograms/kg (0.49--3.0 mg/kg fat). The results confirm that the decline since 1967 in the levels of DDT and its metabolites in Swedish human milk reported by other authors is continuing. The levels of dieldrin and beta-hexachlorocyclohexane found are lower than those reported earlier in Sweden, whereas the levels of hexachlorobenzene are about the same. On the other hand, the levels of PCBs (mean 64 micrograms/kg, range 15--150 micrograms/kg, fresh weight, equivalent to 1.6 mg/kg, range 0.84--2.9 mg/kg, on a fat basis) are higher than those reported earlier in Swedish human milk. Although the calculated intake of the DDT complex (DDT + DDE + DDD) by some of the suckling infants exceeds the acceptable daily intake proposed by a FAO/WHO expert group, it does not constitute a reason for recommending any restrictions on breast feeding--for nutritional, immunological and other reasons it should be encouraged.

Influence of a local source of DDT pollution on statewide DDT residues in waterfowl wings, northern Alabama, 1978-79

Heavy DDT contamination resulting from a former DDT manufacturing plant in northern Alabama has influenced statewide averages of DDT, DDE, and TDE residues in duck wings tested in the National Pesticide Monitoring Program. In states where contaminant levels in duck wings are high, residue analyses of wings categorized by finer geographic subdivision may be useful in defining the areas of heaviest contamination.

Use of selected freshwater bivalves for monitoring organochlorine pesticide residues in major Mississippi stream systems, 1972-73

Seven species of freshwater Pelecypoda, Amblema costata, Corbicula manilensis, Elliptio crassidens, lampsilis anadontoides, Lampsilis claibornensis, Megalonaias gigantea, and Plectomerus dombeyanus, were collected and monitored for pesticide content during 1972 and 1973. Thirteen collection sites, representing five major river basins in the state of Mississippi, were sampled and compared. During the 24-month study, 26 water samples and 58 claim samples from the five river basins were analyzed. Individual samples weighed from 8 g to 20 g and consisted of 1-30 clams, depending on size. Residues of toxaphene and methyl parathion were found only in 1973 water samples. The study shows that freshwater clams are effective monitors of pesticide content. The tendency of clams to concentrate pesticides and their corresponding ability to eliminate them varies with species. Significant reductions in DDT and a corresponding buildup of p,p'-TDE were noted in 1973, following the limitations on the use of DDT and large-scale flooding throughout the state.

DDT residues in samples of human milk, and in mothers' and cord blood serum, in a continental town in Croatia (Yugoslavia)

Concentrations of p,p'-DDE, p,p'-DDD, and p,p'-DDT were determined in 34 samples of human milk obtained 3-5 days after delivery and in 37 samples obtained at later times of lactation (up to 55 weeks). All samples contained p,p'-DDE, but only several contained p,p'-DDD and p,p'-DDT. The concentrations of p,p'-DDE were 31 microgram/l in the beginning of lactation and 53 microgram/l at later time intervals. The concentration ranges in both groups overlap almost completely and the difference in the mean values is not significant. Serum samples from 35 mothers and cord blood were also analyzed. All samples contained p,p'-DDE, the concentrations being 18 microgram/l and 6.8 microgram/l in the mothers' and cord blood serum, respectively. Serum samples of 24 non-pregnant women contained the same amount of p,p'-DDE (20 microgram/l) as mothers' sera. All samples were collected in a continental town of Croatia (Yugoslavia) between 1977 and 1979. The concentrations of DDT residues were determined by gas chromatography, and two methods for extraction from milk were used and compared.