DDE Ratios Research Articles

Legacy and new chlorinated persistent organic pollutants in the rivers of south India: Occurrences, sources, variations before and after the outbreak of the COVID-19 pandemic

During pre-pandemic time, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in the surface water of Periyar River (PR) and Bharathappuzha River (BR) in Ernakulam and Malappuram districts of Kerala, respectively and Adyar River (AR) and Cooum River (CR) in Chennai district of Tamil Nadu. After the outbreak of COVID-19 pandemic, variation in OCPs and PCBs were evaluated for AR and CR. Dominance of β-HCH and γ-HCH in south Indian rivers indicate historical use of technical HCH and ongoing use of Lindane, respectively. In > 90 % sites, p,p′-DDT/ p,p′-DDE ratio was < 1, indicating past DDT usage. However during the outbreak of the COVID-19 pandemic, elevated p,p′-DDT in AR and CR reflects localized use of DDT possibly for vector control. Similarly, during the first wave of pandemic, over a 100-fold increase in PCB−52 in these rivers of Chennai mostly via surface run-off and atmospheric deposition can be reasoned with open burning of dumped waste including added waste plastic in the solid waste stream. On contrary, a significant (p < 0.05) decline of dioxin-like PCBs level, suggests lesser combustion related activities by the formal and informal industrial sectors after the lockdown phase in Tamil Nadu. Eco-toxicological risk assessment indicated a higher risk for edible fish in PR due to endosulfan.

Pilot study on the concentrations of organochlorine compounds and potentially toxic elements in pregnant women and local food items from the Finnish Lapland

In the Arctic, main sources of persistent organic pollutants and potentially toxic elements are industry and agriculture in the lower latitudes. However, there are also local sources of pollution. Our study was focused on possible pollution in the Finnish Lapland, transferred from the Pechenganikel industrial complex located in the borders of Russia, Finland and Norway.Local food items and blood samples of pregnant women from the Inari municipality were collected and organochlorine compounds (OCs) and metal(oid)s analyzed. Most of the examined food samples showed detectable levels of these compounds. The mean concentrations of DDTs and polychlorobiphenyls (PCBs) were higher in fish (0.18–0.32 ng/g and 0.34–0.64 ng/g, respectively), than in the other food groups (0.027–0.047 ng/g and 0.11–0.20 ng/g, respectively).PCBs were found at the highest concentrations in blood samples of the pregnant women, and congeners 153 and 118 were dominant. The mean concentration of PCB153, 0.29 μg/kg serum lipid, was lower than those described in many other studies. Concerning DDTs, the 4,4′-DDT/4,4′-DDE ratio, 0.092, in the blood samples was lower than that observed in the food items, 0.25–0.71, reflecting old uses of the DDT pesticide. None of the observed levels of selected potentially toxic elements in blood samples and in food items exceeded the known safe limits.Higher concentrations of PCB52 and γ-HCH were observed in the serum of pregnant women who consumed greater amounts of meat, and berries and mushrooms, respectively. The OC concentrations from the pregnant women currently studied were lower than those observed fourteen years ago with pregnant women from the same municipality. Compounds whose occurrence is likely related to a long-distance transport showed clear decreases, e.g., 63% for PCBs, and for those from pesticides, decreases were 93% and 97% for 4,4′-DDE and β-HCH, respectively. No obvious influence from the Pechenganikel complex is observed from the results.

Organohalogenated pollutants in raw and UHT cow's milk from Turkey: a risk assessment of dietary intake.

In this study, health risk of human exposure to organohalogenated pollutants (OHPs) through milk consumption was determined. Conventionally produced, unprocessed cow's milk samples taken from Konya District, in Turkey, and 15 different brand ultra-high-temperature (UHT) processed cow's milk samples taken from supermarkets of Turkey were analyzed for organochlorine pesticides (OCPs, α-, β-, γ-, and δ-HCHs, p,p'-DDE, p,p'-DDD, and p,p'-DDT, heptachlor, heptachlor epoxide, endosulfan I, endosulfan II, endosulfan sulfate, endrin, endrin aldehyde, endrin ketone, aldrin + dieldrin, methoxychlor), polychlorinated biphenyls (PCBs, PCB 28, 52, 101, 153, 138, and 180), and polybrominated diphenyl ethers (PBDEs, PBDE 47, 99, 100, 153, and 154 congeners). Estimated daily intake (EDI) values calculated for both adults and children consuming raw or UHT milk were determined to exceed maximum residue limits (MRLs) set for γ-HCH, ∑Heptachlor, and endrin. EDI values also exceeded admissible daily intake (ADI) values given for ∑HCH, ∑Heptachlor, ∑Endrin aldrin + dieldrin, and ∑PCBs. p,p'-DDT/p,p'-DDE ratio was 1 or higher for 66% of the milk samples, which is an indication of sustaining illegal use of DDT. A health risk is determined for dietary intake of OHPs via consumption of milk.

Occurrence and air–soil exchange of organochlorine pesticides and polychlorinated biphenyls at a CAWNET background site in central China: Implications for influencing factors and fate

Ambient air and soil samples were collected between March 2012 and March 2013 at Jinsha, a regional background site in central China, to measure the concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The average concentrations of total OCPs and total PCBs were 191 ± 107 and 39.4 ± 27.1 pg/m3 in air (gaseous and particulate phase) and 0.585 ± 0.437 and 0.083 ± 0.039 ng/g in soil, respectively. The higher concentrations of p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT) and p,p′-DDT/p,p′-DDE ratios in the soil indicated recent p,p′-DDT input to the soil. A strong positive temperature dependence and average fugacity fraction value > 0.5 were observed for p,p′-DDT, suggesting that volatilization of residual DDT in the soil was the main influencing factor on atmospheric p,p′-DDT. Highly average fugacity fractions (>0.7) of trans-chlordane (TC) and cis-chlordane (CC) and high TC/CC ratios both in the soil and atmosphere suggested fresh inputs. Higher gaseous concentrations of hexachlorobenzene (HCB) were observed in winter and negative temperature dependence was directly attributed to the surrounding ongoing source (e.g. fuel consuming activities), especially in winter. Overall, most targeted OCPs and PCBs were influenced by long-range transport, and fugacity fraction values indicated highly volatile compounds (e.g. α-hexachlorocyclohexane (α-HCH) and lower chlorinated PCBs) were volatilized and low volatility compounds (e.g. p,p′-DDE and higher chlorinated PCBs) were deposited at the air–soil interface. Knowing the source and sink of OCPs and PCBs can help to control their pollution in this area and provide a reference for other studies.

Organochlorine pesticides and polychlorinated biphenyls in human adipose tissue from northern Tunisia: Current extent of contamination and contributions of socio-demographic characteristics and dietary habits

The aims of the present study were to investigate the current exposure levels of persistent organochlorine compounds (OCs) in adipose tissues intraoperatively collected from 40 patients over 20 years undergoing non-cancer-related surgery residing in Northern region of Tunisia (Bizerte), which constitutes an exemplary case, and examined association between levels of contamination and both socio-demographic characteristics and dietary habits. Concentration of hexachlorobenzene (HCB), hexachlorocyclohexane isomers (α-HCH, β-HCH, γ-HCH and δ-HCH), dichlorodiphenyltrichloroethane isomers (p,p′-DDT and o,p′-DDT) and metabolites (p,p′-DDE, o,p′-DDE, p,p′-DDD and o,p′-DDD) and 12 polychlorinated biphenyls (PCBs) congeners were measured using capillary gas chromatography with electron capture detector. Overall, residue levels of OCs followed the decreasing order of DDTs > PCBs > HCB > HCHs. DDTs levels ranged from 74.49 to 1834.76ngg−1 lipid and contributing to more than 90% to the sum of organochlorine pesticides (OCPs). p,p′-DDE was the most abundant in all samples and the p,p′-DDT/p,p′-DDE ratio (range between 1.85% and 58.45%) suggesting recent and ongoing exposure to banned commercial DDT products. PCB concentrations varied from 29.27 to 322.58ngg−1 lipid and PCB-180, PCB-153 and PCB-138 were the dominant congeners accounting for 70% of total PCBs. We did not find significant correlations between OC exposure levels and sex, parity, habitat areas and smoking habits. In females, the adipose tissue concentrations of DDTs, HCB and PCB-118 were positively correlated with age. There was statistically significant relationship between body mass index (BMI) changes and the adipose tissue levels of HCB and HCHs. No association was found between OCPs levels and dietary factors. However, our study suggests that fish consumption may be an important contributor of PCBs adipose tissue content of PCBs in Tunisian people. The presented work is highly significant, being the first study pointing out the chronic exposure to OCs in Bizerte.

Levels and profiles of organohalogenated contaminants in human blood from Egypt

Concentrations of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and some organochlorine pesticides (OCPs) were determined in serum of Egyptian colorectal cancer patients (n = 35) and compared to a healthy control group (n = 32). p,p′-DDE (the major metabolite of DDT) was the most frequently detected contaminant with the highest concentration (median = 131 ng/g lw) in all studied serum samples. BDE-209 was the least frequently detected contaminant with a median concentration <0.3 ng/g lw. The contamination profile in patients and controls was almost identical with p,p′-DDE showing the highest median contribution (77%) and oxychlordane the lowest (1%). The low p,p′-DDT/p,p′-DDE ratio (3.7%) in serum implies bioaccumulation and past exposure to DDT (c.f. recent and ongoing intake). Statistical analysis revealed no significant differences (P > 0.05) between the levels of target contaminants in serum of patients and the control group. Gender, age and body mass index (BMI) were investigated as potential factors influencing serum contaminant levels. ΣDDT, hexachlorobenzene and pentachlorophenol concentrations showed significant positive associations with age and/or BMI of the participants. Comparison with other countries revealed concentrations of PBDEs and PCBs in Egyptian serum among the lowest reported worldwide.

Modeling the dynamics of DDT in a remote tropical floodplain: indications of post-ban use?

Significant knowledge gaps exist regarding the fate and transport of persistent organic pollutants like dichlorodiphenyltrichloroethane (DDT) in tropical environments. In Brazil, indoor residual spraying with DDT to combat malaria and leishmaniasis began in the 1950s and was banned in 1998. Nonetheless, high concentrations of DDT and its metabolites were recently detected in human breast milk in the community of Lake Puruzinho in the Brazilian Amazon. In this work, we couple analysis of soils and sediments from 2005 to 2014 at Puruzinho with a novel dynamic floodplain model to investigate the movement and distribution of DDT and its transformation products (dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD)) and implications for human exposure. The model results are in good agreement with the accumulation pattern observed in the measurements, in which DDT, DDE, and DDD (collectively, DDX) accumulate primarily in upland soils and sediments. However, a significant increase was observed in DDX concentrations in soil samples from 2005 to 2014, coupled with a decrease of DDT/DDE ratios, which do not agree with model results assuming a post-ban regime. These observations strongly suggest recent use. We used the model to investigate possible re-emissions after the ban through two scenarios: one assuming DDT use for IRS and the other assuming use against termites and leishmaniasis. Median DDX concentrations and p,p'-DDT/p,p'-DDE ratios from both of these scenarios agreed with measurements in soils, suggesting that the soil parameterization in our model was appropriate. Measured DDX concentrations in sediments were between the two re-emission scenarios. Therefore, both soil and sediment comparisons suggest re-emissions indeed occurred between 2005 and 2014, but additional measurements would be needed to better understand the actual re-emission patterns. Monte Carlo analysis revealed model predictions for sediments were very sensitive to highly uncertain parameters associated with DDT degradation and partitioning. With this model as a tool for understanding inter-media cycling, additional research to refine these parameters would improve our understanding of DDX fate and transport in tropical sediments.

Organochlorine pesticides and PCBs in Southern Right Whales (Eubalaena australis) breeding at Península Valdés, Argentina

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were assessed in blubber from 35 dead Southern Right Whales (SRW — Eubalaena australis) stranded at Península Valdés, Argentina. The life cycle includes a feeding period in high productivity areas of the South West Atlantic and a reproductive period in coastal template waters of Argentina. Organochlorine pesticides showed higher concentrations (22.6±13.8ng·g−1ww) than PCBs (7.5±10ng·g−1ww). Among pesticides, HCHs, DDTs, endosulfans, dieldrin, chlordans, heptachlor epoxide, and trans-nonachlor were detected. p,p′-DDE and p,p′-DDT were present in 69% and 26% of samples, respectively. p,p′-DDT/p,p′-DDE ratio showed low values (<0.33) as a result of aged DDT inputs. However, the occurrence of only p,p′-DDT in some samples suggests a recent pesticide input. α-HCH/γ-HCH ratio (<DL-0.37) indicated no recent contribution of technical HCH mixture and/or current use of lindane. Dieldrin was present in 77% of the samples and endosulfan was detected in all samples with predominance of α- (75%) over β-endosulfan (19%) and scarce contribution of endosulfan sulphate (7%), suggesting a recent input of this insecticide to the environment in the SRW foraging area. A predominance of pentachlorobiphenyls was observed. In 21 samples at least one PCB indicator was found and PCB #118, highly toxic, contributed in 5% to total PCBs. Although all these organochlorine compounds are forbidden they were bioaccumulated in the blubber of SRW with a predominance of endosulfans, the more recently used pesticide. The absence of data on chemical pollutants in stranded dead whales is highlighted as a priority for research. This is the first study on levels, compositional patterns, and organochlorine sources in SRW. Moreover, more research including milk, and other tissues/organs is recommended considered that in the studied specimens, mostly calves, pollutants are likely transferred from the mother during pregnancy and nursing.

Vertical distributions of organochlorine pesticides and polychlorinated biphenyls in an agricultural soil core from the Guanzhong Basin, China.

The concentrations and distributions of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), and polychlorinated biphenyls (PCBs) in an agricultural soil core in the Guanzhong Basin, China were determined. Overall, p,p'-DDT and p,p'-DDE were dominant contaminants and accounted for approximately 48.4 and 23.3% of the total detected DDTs. Low chlorinated PCBs (PCB 28 and PCB 52) were generally detected at higher concentrations and more frequently than high chlorinated PCBs. The peak values of ∑DDT (12.92 ng/g), ∑HCH (2.25 ng/g), and ∑PCB (3.44 ng/g) occurred in the 10-15, 15-20, and 5-10 cm sections, respectively. The negative correlation between the organochlorine pesticide (OCP) concentrations and the soil depths and the relatively high p,p'-DDT/p,p'-DDE ratios in the surface soils indicated that these chemicals were recently used illegally, despite their official ban in 1983. The increase in the ratio of α-/γ-HCH with increasing soil depth indicated that the use of lindane decreased relative to the use of technical HCHs in recent years.

PCBs, p,p’-DDE and birth outcomes in 11 European birth cohorts: dose-response relationship and effect modifiers

Background: Low-level exposure to polychlorinated biphenyls (PCB) is inversely associated with fetal growth, but the dose-response relationship and effect modifiers of such association are not well established. This study is an extension of an earlier European meta-analysis. Aims: To explore the dose-response relationship between PCB-153 and p-p’-DDE and selected pregnancy outcomes, and to evaluate if no-effect threshold and susceptible subgroups exist. Methods: We used a pooled dataset of 8702 mother-child pairs enrolled in 14 study populations from 11 European birth cohorts. General additive models were used to evaluate the shape of the relationship between organochlorine compounds and pregnancy outcomes and analysis of interactions were performed. Results: We observed an inverse linear dose-response relationship between prenatal exposure to PCB-153 at levels below 1200 ng/L and birth weight (?=-200 g/µg PCB-153, 95%CI: -338, -62). No threshold or no-effect levels at very low PCB-153 concentrations were identified. The greatest reductions on birth weight were found in girls and in children born from smoking and non-Caucasian mothers. We also found a small but statistically significant alteration in gender ratio for PCB-153 (OR: 1.019; 95%CI: 1.001, 1.038) and p,p’-DDE exposure (OR: 0.992; 95%CI: 0.999, 0.996), corresponding to an increase and a decrease in the proportion of girls, respectively. Conclusions: This study suggests that the association between low-level exposure to PCB-153 and birth weight follows an inverse linear relationship. Our study also suggests that gender, maternal smoking, and ethnicity are effect modifiers of such association. Whether weak associations between PCB-153/p,p’-DDE and gender ratio reflects biological mechanisms remains to be established.

Population characteristics of young African women influencing prenatal exposure to DDT (Manhiça, Mozambique)

The concentrations of dichlorodiphenyltrichloroethane (DDT) compounds in cord blood of 214 children born between 2003 and 2006 in Manhiça (Mozambique) have been determined. In this time interval, corresponding to the period before DDT reintroduction for indoor residual spraying, the observed values averaged 0.8 and 0.4 ng/ml for 4,4'-dichlorodiphenyldichloroethylene (4,4'-DDE) and 4,4'-DDT, respectively, and were similar to those found in western countries. However, the 4,4'-DDT/4,4'-DDE ratio was high indicating that the inputs of these compounds arriving to children in utero originated from recent uses of the insecticide. The strongest factor affecting DDT concentration was parity. A well-defined decreasing concentration trend was observed for the cord blood concentrations in the period of study. The trend was also observed for multiparae and primiparae mothers independently. Children from multiparae women showed much lower concentrations than primiparae women. Children from mothers with secondary school level exhibited lower concentrations of these pesticides than mothers with lower degree of education.

Concentrations of DDTs and Enantiomeric Fractions of Chiral DDTs in Agricultural Soils from Zhejiang Province, China, and Correlations with Total Organic Carbon and pH

Dichlorodiphenyltrichloroethanes (DDTs) are persistent organic pollutants that were widely used in China, especially eastern China, as insecticides. This work investigated the concentration, dissipation, and volatilization of DDTs and enantiomeric fractions (EFs) of o,p'-DDD and o,p'-DDT in agricultural soils collected in 2006 from 58 sites in Zhejiang province. Correlations between DDT residues and soil properties were assessed to determine the effect of soil properties on the environmental attenuation of DDTs. High concentrations and detection frequencies were found for DDTs in agricultural soils in the region even though large-scale use of DDTs was banned over 20 years ago. The amount of DDTs was about 485 tons in the upper 20 cm of the soil column of cropland in the province in 2010, with a dissipation half-life of ~9 years. The mass flux of DDTs was 43 ng m(-2) h(-1), which corresponds to emissions of 7.6 tons with an emission factor of 1.6% in 2006. The low p,p'-DDT/p,p'-DDE ratios and high o,p'-DDT/p,p'-DDT ratios suggest that there were no recent inputs of DDTs but fresh application of dicofol, which contains DDT (o,p'-DDT in particular) impurities. The significant positive correlation between concentrations of DDTs and total organic carbon content (TOC) indicates the distribution of DDTs fit a typical "secondary distribution" pattern. DEVrac of o,p'-DDD, which is defined as the absolute value of EFs subtracted from 0.5, was significantly related with most of the physicochemical and microbial soil properties. The most significant correlation is that between DEVrac of o,p'-DDD and soil pH (p < 0.001), indicating that the soil pH plays a key role in enantioselective residues of DDTs.

Levels and seasonal variations of organochlorine pesticides in urban and rural background air of southern Ghana

Urban, suburban and rural background air samples were collected in southern Ghana in 2008 employing polyurethane foam disc passive air samplers (PAS). PAS were analysed for organochlorine pesticides (OCPs), namely hexachlorocyclohexanes (α-, β-, γ- and δ-hexachlorocyclohexane), dichlorodiphenyltrichloroethane including metabolites (o,p'- and p,p'-DDT, DDE and DDD), hexachlorobenzene, pentachlorobenzene, aldrin, dieldrin, endrins (endrin, endrin aldehyde and endrin ketone), isodrin, heptachlors (heptachlor, heptachlor epoxide A and heptachlor epoxide B), chlordanes (α-, β-chlordane, oxychlordane and trans-nonachlor), endosulfans (α- and β-endosulfan and endosulfan sulphate), methoxychlor and mirex using a gas chromatograph coupled to a mass spectrometer. The levels of OCPs ranged for the individual pesticides from below limit of quantification to 750 pg m(-3) (for α-endosulfan), and current agricultural application seemed to be the main primary source of most abundant pesticides. Re-volatilization of previously used pesticides from contaminated soils could not be ruled out either as potential secondary source of contamination, especially in warm and dry seasons and periods of intensive agricultural activities. Higher atmospheric concentrations were observed in November and December during the dry season compared to lower concentrations observed in June, July and August when the country experiences heavy rains. The highest seasonal variation was observed for currently used pesticides as α-endosulfan. A p,p'-DDT/p,p'-DDE ratio suggested recent inputs of fresh technical DDT.

Levels of Organochlorine Pesticide Residues in Blood Plasma of Various Species of Birds from India

Concentrations of organochlorine pesticides (OCPs) were measured in blood plasma of 13 species of birds collected from Ahmedabad, India. Among the various OCPs determined, HCHs and its isomers had higher contribution to the total OCPs. Concentration of summation operatorHCHs varied from 11.4 ng/mL in White ibis Threskiornis melanocephalus to 286 ng/mL in Sarus Crane Grus antigone, while summation operatorDDT ranged between 19 ng/mL in Black Ibis Pseudibis papillosa and 147 ng/mL in Painted Stork Mycteria leucocephala. p,p'-DDE was accounted for more than 50% of total DDT in many of the samples analysed. However, a p,p'-DDT to p,p'-DDE ratio higher than one obtained for many species of birds indicates the recent use of DDT in this study region. The concentrations of cyclodiene insecticides, heptachlor epoxide, dieldrin and total endosulfan ranged from 15.8 to 296.2 ng/mL, below detectable level to 15 and 41.1-153.2 ng/mL, respectively. The pattern of total OCP load generally occurred in the following order: granivores < insectivores < omnivores < piscivores < carnivores. Although, the organochlorine residues detected in blood plasma of birds are not indicative of toxicity, the presence of residues in birds over the years (2005-2007) indicates continued exposure to organochlorine compounds. However, continuous monitoring is recommended to facilitate the early identification of risks to the survival of a species.

Organochlorine pesticides and polybrominated diphenyl ethers in irrigated soils of Beijing, China: Levels, inventory and fate

Limited information on the levels, inventory and fate of Organochlorine pesticides (OCPs) and Polybrominated diphenyl ethers (PBDEs) in the soils irrigated by sewage or wastewater is available. In this study, variation in concentrations, profiles and fate of OCPs and PBDEs were investigated using soil samples collected from a region irrigated by sewage, mixed water and clean water in the east of Beijing, China. No significant variation was observed among groups, except for penta-BDEs. The measured ΣOCPs and ΣPBDEs residues ranged from 6.4 to 171.2 ng g −1 (dw) and 501.9 to 3310.7 pg g −1 (dw), respectively. ΣDDTs and BDE-209 were the most abundant congeners accounting for about 76% of ΣOCPs and 93% of ΣPBDEs. Concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane (DDTs) and its major degradation products, and hexachlorobenzene (HCB) ranged from 1.2 to 11.4 ng g −1 (dw), 4.0 to 155.6 ng g −1 (dw) and 0.3 to 3.4 ng g −1 (dw), respectively. The major DDT degradation products were p, p′-DDT and p, p′-DDE. The major hexachlorocyclohexane (HCH) isomer in irrigated soils is β-HCH, reflecting its higher affinity to solids and resistance to degradation than other isomers. Both α-HCH/β-HCH and p, p′-DDT/ p, p′-DDE ratios were log-normally distributed and negatively correlated to log(ΣHCHs) and log(ΣDDTs), respectively, suggesting no significant recent application of OCPs. Individual BDE congeners, ΣPBDEs and ΣOCPs were significantly correlated with total organic carbon (TOC). Moreover, a good correlationship between ΣPBDEs and black carbon (BC) was obtained but not between ΣOCPs and BC. Sewage irrigation did not have obvious effect on their contaminant levels and inventory of OCPs and PBDEs.

Interspecific differences in concentrations and congener profiles of chlorinated and brominated organic pollutants in three insectivorous bird species

We investigated the accumulation of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) in eggs of three insectivorous bird species, the great tit ( Parus major), the Northern lapwing ( Vanellus vanellus) and the Mediterranean gull ( Larus melanocephalus), near the harbour of Antwerp (Belgium). Our results show that lapwing eggs had the highest median concentrations of PCBs (4358 ng/g lw) and PBDEs (109 ng/g lw). Mediterranean gulls feed during breeding on ground-dwelling invertebrates on agricultural fields, which is reflected in higher OCP concentrations in eggs (1235 ng/g lw). Apart from differences in accumulation, also interspecific differences in contaminant profiles were investigated. Significant differences among species were found in the profile of PCBs, PBDEs and OCPs. These differences could be attributed to differences in diet, behaviour and metabolic capacity. Interestingly, the OCP profile in lapwing eggs deviated extremely from the two other species. In both great tit and Mediterranean gull eggs p, p′-DDE was by far the most important compound, whereas in lapwing eggs hexachlorobenzene, oxychlordane, trans-nonachlor and even p, p′-DDT were relatively more abundant than p, p′-DDE. The high p, p′-DDT/ p, p′-DDE ratio has previously been described in lapwings, which suggests that low p, p′-DDE accumulation in eggs might be inherent for this species.

Organochlorine Pesticides Contaminated Surface Soil As Reemission Source in the Haihe Plain, China

A large amount of organochlorine pesticides (OCPs) including hexachlorocyclohexane isomers (alpha-HCH, beta-HCH, gamma-HCH, and 6-HCH,sigmaHCH asthe total) and dichlorodiphenyltrichloroethane and metabolites (p,p'-DDT, p,p'-DDE, and p,p'-DDD, sigmaDDT as the total) have been applied over the Haihe Plain (an area of 300 000 km2) in Northern China. Even though the agricultural application of these OCPs was terminated more than a decade ago, their residues remain in the environment and continue to represent significant public health concern. In this study, more than 300 surface soil samples were collected from the Haihe Plain for measurement of these OCPs. The measured sigmaHCH and sigmaDDT residues were 3.9 +/- 26 and 64 +/- 260 ng/g as arithmetic means and standard deviations with median values of 0.38 and 6.5 ng/g, respectively. Although the levels were approximately 1 order of magnitude lower than those recorded in 1980s, it was estimated that there were 430 +/- 110 tons of sigmaHCH and 6100 +/- 760 tons of sigmaDDT in the surface soil of the area, respectively. The soils with high levels of OCP residuals were mostly distributed on the fringes of major cities, due to intensive farming and discharge from pesticide producers in the cities. The residuals of sigmaHCHs and sigmaDDTs were significantly correlated to soil organic matter content. Both alpha-HCH/beta-HCH and p,p'-DDT/p,p'-DDE ratios were log-normally distributed and negatively correlated to log(sigmaHCH) and log(sigmaDDT), respectively. Thus these ratios and correlations preclude certainty in distinguishing fresh application from historical usage. According to the total residuals and the distributions of alpha-HCH/beta-HCH and p,p'-DDT/p,p'-DDE ratios, it appears that significant recent input of either the OCPs is very unlikely. The calculated fugacities in soil and air provided quantitative evidence indicating a net and seasonally varied transport of sigmaHCH (0.31 ton/year) and sigmaDDT (1.9 ton/year) from soil to atmosphere in the study area. Such a surface-to-air transport suggested that after the ban, the surface soil had gradually converted from a major sink to an important emission source of OCPs and the reemission will continue for many years to come.

DDT levels in human milk in Hong Kong, 2001–02

High levels of p, p′-DDT were detected in Hong Kong breast milk sampled in 1976 and 1985. Monitoring DDT levels in human breast milk in this region is important to identify trends in exposure. As part of the 2002–03 WHO/EURO coordinated exposure study, the concentrations of DDT and its metabolites were determined in 10 pooled milk samples classified by geographic origin and dietary history, comprising milk samples from 238 primiparous mothers giving birth in Hong Kong. Analysis was performed by Gas Chromatography (GC) with electron capture detector and confirmed by GC/Mass Spectrometry. The sum-DDT concentration (range: 0.92–2.05 mg/kg fat) was age-dependent and indicated a decreasing trend since the 1970s. Mothers who recently came from mainland China had higher p, p′-DDT to p, p′-DDE ratios, suggesting a more recent exposure compared to women mainly residing in Hong Kong. The average Hong Kong sum-DDT level (1.50 mg/kg fat) was among the highest of the contemporary levels (range: 0.12–1.97 mg/kg fat; median: 0.40 mg/kg fat) in the 16 countries/regions participating in the 2002–03 WHO/EURO exposure study. This is probably due to the previous extensive DDT exposure and continuing use of DDT in agriculture in mainland China. Despite the apparent decrease of DDT body load over 30 years, the environmental health hazard from DDT contamination in the Pearl River Delta region remains a concern. Measures to eradicate illegal use of DDT in mainland China and regular food monitoring programs are needed in the region. Despite the presence of DDT and other persistent organic pollutants in human breast milk, breastfeeding should continue to be strongly supported for its life-long benefits to infants.

ＰＯＰｓ関連物質の加熱挙動に関する研究

In Japan, large quantities of pesticides are stockpiled in many locations. The Japanese government aspires that these pesticides should be regulated by treating them as per the regulations of the Stockholm Convention which came into effect from the year 2004, controlling twelve persistent organic pollutants (POPs). Therefore, it has become mandatory to develop technologies that can effectively destroy these stockpiled pesticides safely and effectively. Having this in mind, in this study, the removal and elimination efficiency of DDTs, aldrin and BHC (HCHs) was investigated heating mixed samples of these pesticides in a tubular furnace coupled with a secondary combustion chamber, in presence of air or nitrogen. We observed no difference in the volatilization temperatures of these pesticides when the samples were heat-treated either under nitrogen or air. When the sample was heated to 600°C under a nitrogen atmosphere, an increase in the ratio of DDE in total DDTs was observed. About 90% of the aldrin was destroyed. BHC was volatilized almost completely at this temperature but did not disintegrate at all. A high removal rate was observed for all the chemicals when the flue gas from the tubular furnace was heated to 1,100°C in the secondary combustion chamber. However, the volatilization rate of BHC (HCHs) decreased when the oxygen concentration in the secondary combustion chamber was lowered. This study proves the effectiveness of a system designed to vaporize pesticides through heating in a furnace at high temperature followed by combustion of the flue gas.

Residues of DDT and other selected organochlorine pesticides in soils from Saskatchewan, Canada (1999)

A study of samples from a broad range of soils across the province of Saskatchewan, Canada, in 1999 has shown evidence that residues of organochlorine pesticides, and in particular DDT [1,1,1-trichloro-2,2- bis(4-chlorophenyl)ethane] and related compounds, are present even after several decades since the last application. In particular, residue levels of total DDT {DDTt = DDT + DDD [1,1-dichloro-2,2- bis(p-chlorophenyl)ethane] + DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene]} in Prince Albert National Park approach some of the highest levels measured to date at non-agricultural locations with concentrations of 119 to 150 ng g-1. Ratios of DDT:DDD:DDE were relatively consistent even from sites separated by several hundred kilometers and seem to be independent of soil properties and sample moisture levels over the region of study. These DDT:DDD:DDE ratios ranged from 9:1:4 for the Prince Albert Park site to 5:1:2 for Agriculture and Agri-Food Canada (AAFC) Research Centres and privately owned agricultural land. Data collected from AAFC Research Centres showed somewhat elevated levels of lindane [γ-1,2,3,4,5,6-hexachlorocyclohexane] (maximum 14 ng g-1), dieldrin [(1R,4S,4aS,5R,6R,7S,8S,8aR)-1,2,3,4,10,10-hexachloro-=6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro- endo-1,4,-exo-5,8-dimethanonaphthalene] (maximum 27 ng g-1) and chlordane [1,2,4,5,6,7,8,8-octachloro-2,3,3a,4,7,7a-hexahydro-4,7-methanoindene] (maximum 10 ng g-1), while samples collected from sites designated as “background” locations demonstrated a minimal effect from long-range atmospheric transport of organochlorines. Key words: Organochlorine residues, soil, Canada, decomposition products, pesticides