deposition record of organochlorine pesticides in a sedimentary core

Downloaded By: [Zhejiang University] At: 08:11 20 November 2009

J. ENVIRON. SCI. HEALTH, A36(10), 1873–1890 (2001)

DEPOSITION RECORD OF ORGANOCHLORINE PESTICIDES IN A SEDIMENTARY CORE IN MACAO ESTUARY, PEARL RIVER, CHINA Yuehui Kang,1,2,* Guoying Sheng,2 Jiamo Fu,2 and Zijian Wang1 1

State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P.R. China 2 State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, P.R. China

ABSTRACT This paper present the concentration profiles of the organochlorine pesticides in a sediment core from Macao Estuary, Pearl River, China. Concentrations of organochlorine pesticides were determined by GC/ ECD and GC/MSD, and the core was dated by 210Pb method in a content-activity model. The results show that the concentrations of HCHs and DDTs in the core ranged from 0.48–26.3 and 1.92–39.1 mg/kg, respectively. Concentration of DDTs in the research area was above the Effects Range-Low value (ERL) for Marine and Estuarine sediments. The vertical distributing of organochlorine pesticides in the core was influenced by the water flux of Pearl River and the pollutants are mainly attributed to the runoff of local agricultural soils. Key Words: Organochlorine pesticides; Concentration; Sedimentary core; Macao Estuary, Pearl River

*Corresponding author. E-mail: [email protected] 1873 Copyright

#

2001 by Marcel Dekker, Inc.

www.dekker.com

ORDER

REPRINTS

1874

KANG ET AL.


INTRODUCTION Organochlorine pollutants, such as dichloro-diphenyl-trichloroethane (DDT) and hexachlorocyclohexane (HCH), have been known for their long persistence in the environment. Their large-scale application of these chemicals in agriculture and in medicine has resulted in an elevated concentration in aquatic systems. From 1953 to 1983, the total amounts of HCH and DDT used in China estimated were 4.9 109 and 0.4 109 kg, respectively (1). The total amount of HCH used in China during this period was almost three times as high as that used in other countries of the world. Furthermore, the total amount of DDT used in China accounted for about 20 percent of the total use in the world (1). The application of organochlorine pesticides (DDT and HCH) was banned in 1983 in China. Unlike in the developing countries, less work has been done on their concentrations in the Chinese environment. Pearl River is the major river in southern part of China and flows into South China Sea. The delta of the river includes geographically Hong Kong and Macao and acts as a main reservoir of organic contaminants from mainland sources. In the last two decades, the areas in the surroundings of the Pearl River delta have developed rapidly and is considered as one of the most prosperous economic zones in China. The rapid increase in population, development of industries and large-scale land exploitation have resulted in a large-scale contamination of pollutants. While there is limited data on concentration levels of the pollutants in surface sediment (2), well preserved, laminated sediment from core could usually be used to reconstruct the pollution history of organic compounds (3–7). Systematic study has been conducted on the distribution, transportation and evolution of the priority organic contaminants in the Pearl River Delta from 1996 to 1999. This work presents the results of concentration profiles and deposition records of organochlorine pesticides in a sedimentary core from Macao Estuary, Pearl River. The vertical variation of organochlorine pesticides concentrations in the core and their origins are also described.

MATERIALS AND METHODS Sampling and Dating A core of 73 cm in length (ZJ-9 in the series) was collected in Macao Estuary, located at N22 120 1000 and E113 320 0200 . The sampling location is shown in Figure 1. The depth of water column at the location was 3 m. A stainless steel static gravity corer (I.D. 8 cm) was employed to ensure the undisturbance of the stratal-graphic profile and the sediment-water interface. The core was sectioned into 2-cm interval in situ and the sectioned sediment

ORDER

REPRINTS


ORGANOCHLORINE PESTICIDES IN SEDIMENTARY CORE

Figure 1.

1875

Sampling location of a sedimentary core in Macao Estaury, Pearl River.

samples were immediately packed into clean aluminum jars and stored at 40 C before manipulation. To obtain the chronological date, sediment sub-samples were subjected to the analysis for 210Pb isotope. The sedimentary core was dated by use of the content-activity model (CAM) of the 210Pb-dating method (8). The results showed that the deposition of the core lasted for 40 years and the averaged deposition rate for the core was 1.87 cm/a. The averaged deposition flux was calculated to be about 1.52 g/cm2/a.

Extraction and Clean-up of Samples Sediment samples were freeze-dried and ground. A 20 g aliquot dry sample was spiked with known amounts of surrogate standard before

ORDER

REPRINTS


1876

KANG ET AL.

extraction. The sediment samples were Soxhlet extracted with 200 ml mixtures of dichloromethane and acetone (1 : 1, v/v) for 72 h. Two grams of active copper-sheet was added to the bottom of flask to remove element sulfur. The extract was concentrated by a gentle stream of nitrogen (GR grade) and then re-dissolved in hexane. The samples were passed through a silica gel column (60–80 mesh, activated at 180 2 C for 12 h before use) and then a glass-column (10 mm I.D) filled with 6 cm of alumina (100–200 mesh, activated at 250 2 C for 12 h) and 12 cm of silica gel. The column was eluted with 15 ml hexane and 70 ml mixture of dichloromethane and hexane (30 : 70, v/v), respectively to obtain 2 fractions, i.e., the aliphatic and aromatic fraction. The aromatic fraction, containing organochlorine pesticides and PAHs, was concentrated to a final volume of 0.2 ml using a gentle stream of nitrogen. After addition of the internal standards, 1 ml of the purified extract was injected into a GC/ECD in splitless mode to analyze the concentrations of pesticides. In our study, 2,4,5,6-tetrachloro-m-xylene (TMX) and decachlorobiphenyl (PCB209) were used as an internal standard and 4,40 -dichlorobiphenyl (PCB15) was used as surrogate.

Conditioning the Instruments Organochlorine pesticides were analyzed by a gas chromatograph (HP5890 Series II) equipped with a 63Ni electron capture detector (GC/ECD) and a HP-5 fused silica capillary column (50 m 0.32 mm i.d., film thickness of 0.17 mm). The analysis was also performed on a gas chromatography/mass spectroscopy (GC/MS) to confirm the identification. The temperature of the injector was kept at 250 C and the temperature of the detector was kept at 280 C. The temperature of the column oven was programmed from 100 C to 290 C at an increasing rate of 4 C/min, with a final hold for 10 min. Nitrogen gas of extra purity was used as a carrier gas. The flow rate was 2.5 ml/min and the pressure was kept at 120 kPa. One microlitre of the purified extract was injected into GC/ECD or GC/ MS (HP-5890-II GC and HP-5972 MS) in splitless mode. Quantitative determination was carried out using internal standard method based on a 6-points calibration in GC/ECD. Qualitative analysis was confirmed by using GC/MS at the same chromatographic conditions with Selected Ion Monitoring mode (SIM).

Quality Control Procedures The procedures were supervised by a quality assurance and quality control (QA/QC) process modified in the laboratory (9). The QA/QC

ORDER

REPRINTS



1877

performance includes blanks, spiking blanks, matrix, matrix duplicate, sample and sample duplicates. Organic solvents employed in the experiment, such as hexane (C6H12), dichloromethane (CH2Cl2), acetone (CH3COCH3), methanol (CH3OH), were of analytical grade and distilled by all-glass systems before use. Standard mixture of organochlorine pesticides (US-1128) contained 17 organochlorine pesticides including -HCH, -HCH, -HCH (Lindane), -HCH, heptachlor, aldrin, heptachlor epoxide, endosulfan I, dieldrin, p, p0 -DDE, endrin, endosulfan II, p, p0 -DDD, endrin aldehyde, endosulfan sulfate, p, p0 -DDT, endrin ketone and methoxychlor. The standard mixture was purchased from Ultra Scientific Co., USA and their chromatography separation is shown in Figure 2. For quality control of gas chromatographic conditions, a checkout procedure was performed before sample analysis. In the procedure, a standard mixture with DDT content of 15% was used and the calibration was carried out when the percentage of DDT in standard mixture was deviated significantly from 15%. The mixture of p, p0 -DDT and o, p0 -DDT was also purchased from Ultra Scientific Co. The single o, p0 -DDT (GSBG-23008-92) was purchased from China National References Research Center in Beijing. By using standards, the detection limit ranged from 0.11–0.35 mg/kg (dry weight) and the recovery (PCB15) ranged from 97–99.4 percent. We estimated that the recovery for the target compounds should be in the range of 61–102 percent (9). Concentrations of HCHs and other organochlorine pesticides in the sediment samples were calculated and corrected by surrogate (PCB 15). The recoveries for added surrogate in these core samples were

Figure 2. Gas chromatography of the reference standard material of organochlorine pesticide mixture. 1. 2,4,5,6-tetrachloro-m-xylene (I.S.). 2. -HCH. 3. -HCH. 4. -HCH (Lindane). 5. 4,40 -dichlorobiphenyl (PCB15) (S.S.). 6. -HCH. 7. Heptachlor. 8. Aldrin. 9. Heptachlor epoxide. 10. Endosulfan I. 11. Dieldrin. 12. p, p0 -DDE. 13. Endrin. 14. Endosulfan II. 15. o, p0 -DDT. 16. p, p0 -DDD. 17. Endrin aldehyde. 18. Endosulfan sulfate. 19. p, p0 -DDT. 20. Endrin Ketone. 21. Methoxychlor. 22. decachlorobiphenyl (PCB209) (I.S.).

ORDER

REPRINTS

1878

KANG ET AL.

found in the range of 85–104 percent, which 40 mg of PCB15 were spiked to the sediment samples before Soxhlet extraction to compensate for losses involved in the sample extraction and work-up, to further improve the analytical quality.

RESULTS AND DISCUSSION


Concentrations of Organochlorine Pesticides in Sedimentary Core The concentrations of organochlorine pesticides in the sedimentary core are shown in Table 1 and Table 2. On freeze-dried weight basis, the total concentration of organochlorine pesticides ranged between 7.25–86.35 mg/kg. The average concentration was 27.45 mg/kg. The amounts of HCHs (including -, -, -, -isomers) and DDTs (DDT and its main metabolites o, p0 DDD, p ,p0 -DDD, o, p0 -DDE and p, p0 -DDE) were 0.48–26.28 and 1.92– 39.13 mg/kg, respectively. Their averages were 3.88 and 10.53 mg/kg, respectively. In 1980, a geochemical survey had been conducted in Pearl River Mouth, in which the concentrations of HCHs were 4.2–90 mg/kg with an average of 37 mg/kg and those of DDTs were 0.3–72.3 mg/kg with an average of 6.2 mg/kg in surfacial sediment, respectively (10). In comparison, the concentrations of organochlorine pesticides in surface sediment have been decreased in the recent years. Compounds such as aldrin, endrin and methoxychlor were also detected in trace amounts. Compounds such as o, p0 -DDT and endrin aldehyde were found to have very low concentrations in the core samples. The concentration of HCHs in the core varied with the depth (Table 1). Two peaks appeared at the depth intervals of 24–26 cm represented the deposition time of 1983–1985 and 50–72 cm, respectively (Figure 3a). Among the 4 isomers of HCHs, the increase of HCHs was mainly caused by increase of -, -HCH isomers. The commercial pesticides typically contained 60–70 percents of -HCH, 5–12 percents of -HCH, 10–12 percents of -HCH, 6–10 percents of -HCH, as well as 3–4 percents of "-HCH isomer. Among them, -HCH (Lindane) was the most active and degradable component. Therefore, the ratio of to -HCH isomer can be used to track global transport of HCHs (11). The ratio of to -HCH in sediment core varied from 0.1 to 3.1 and implied the chemical conversions occurred in the sediment, because the ratio of to - in the technical-grade HCHs varies between 4–7. Evidence shows that -BHC isomer can be transformed into other isomer especially as - and -HCH in sediment through biodegradation (12). In environment, most likely dominating BHC isomers in sediment of Pearl River Delta were - and -HCH. Ayas (13) concluded that DDT, aldrin and heptachlor have been found in higher quantities than their converted products. In the studied

Deposition Date (y.m.)

199609–199703 199404–199508 199301–199404 199111–199301 199010–199111 198906–199010 198802–198906 198701–198802 198601–198701 198501–198601 19831–1985011 198211–198311 198109–198211 198008–198109 197908–198008 197807–197908 197706–197807 197605–197706 197504–197706 197401–197504 197302–197401 197202–197302 197101–197202 197001–197101 196901–197001

Depth (cm)

0–2 4–7 7–9 9–11 11–13 13–16 16–18 18–20 20–22 22–24 24–26 26–28 28–30 30–32 32–34 34–36 36–38 38–40 40–42 42–44 44–46 46–48 48–50 50–52 52–54

Table 1.

0.59 0.39 0.86 1.17 0.82 0.85 0.75 0.61 0.93 0.32 0.24 0.44 0.40 0.20 0.54 0.48 0.48 0.57 0.78 0.57 0.36 0.50 0.42 0.73 0.93

0.43 0.39 1.14 1.29 0.88 1.19 0.85 0.61 1.52 0.16 0.56 0.42 0.28 0.16 0.48 0.42 0.39 0.59 0.98 0.25 0.28 0.16 0.27 1.57 1.16

0 0.22 0.65 0.41 0.01 0.44 0.26 0.13 0.17 0 5.24 0.28 0.24 0.06 0.43 0.29 0.16 0.29 0 0.21 0.13 0.24 0 6.06 9.43

0 0.08 0.26 0.18 0.15 0.25 0.22 0.14 0.34 0.06 0.09 0.18 0.12 0.06 0.25 0.17 0.18 0.25 0.33 0.17 0.14 0.09 0.03 0.23 0.25

-

HCHs (ng/g)

1.02 1.08 2.92 3.06 1.85 2.73 2.08 1.50 2.97 0.53 6.13 1.31 1.05 0.48 1.70 1.36 1.21 1.70 2.10 1.21 0.90 1.00 0.73 8.59 11.76

4.83 2.33 1.96 0.82 3.75 1.35 0.78 0.66 0.34 0.46 0.58 1.29 0.47 0.60 0.65 0.69 0.71 0.87 0.59 0.91 1.04 0.71 0.96 1.30 0.83

Aldrin (ng/g) 1.50 0.90 0.84 0.93 1.90 0.70 0.57 0.68 0.73 0.53 0.28 0.43 0.73 0.50 1.03 1.24 1.41 0.85 0.68 1.56 1.12 1.39 1.20 1.69 1.88

Endrin (ng/g) 13.77 6.26 9.77 12.67 15.60 14.51 3.52 10.59 11.61 9.09 0 0 2.83 1.64 0 0 5.17 0 0 4.15 14.10 0 4.64 6.99 7.95

Endosulfan Sulfate (ng/g) 2.06 1.54 2.91 3.23 3.13 4.06 2.98 3.31 2.90 1.85 0.92 0.76 2.92 1.17 2.23 3.25 4.23 2.90 6.36 3.72 2.20 3..41 4.92 4.95 2.93

Endrin Ketone (ng/g) 5.28 1.14 2.35 2.27 2.30 3.60 2.71 10.01 0.32 0.45 3.11 9.56 1.71 1.37 4.05 1.57 7.21 22.09 1.76 5.22 1.47 2.48 6.53 3.62 3.92

36.09 10.3 20.33 16.56 20.34 18.60 12.21 18.24 13.81 7.25 17.21 20.0 13.07 8.08 18.58 19.42 27.28 37.97 26.56 24.81 15.81 13.22 22.14 33.61 32.83

Total* (ng/g)

ORGANOCHLORINE PESTICIDES IN SEDIMENTARY CORE (continued )

Methoxychlor (ng/g)

Concentrations of HCHs, Aldrin, Endrins, and Methoxychlor in Dated Core from Macao Estuary


ORDER REPRINTS

1879

196712–196901 196609–196712 196508–196609 196408–196508 196307–196408 196206–196307 196106–196206 196005–196106 195901–196005 195806–195901

54–56 56–58 58–60 60–62 62–64 64–66 66–68 68–70 70–72 73

0.69 0.75 0.64 1.63 1.20 0.97 1.29 0.96 1.15 0.68

0.21 1.38 1.36 6.82 0.55 0.66 1.42 2.47 1.67 9.93

0 4.8 0 0 0 7.33 0 4.41 3.89 15.6

0.15 0.20 0.34 0.56 0.09 0.17 0.40 0.37 0.12 0

-

HCHs (ng/g)

1.05 7.12 2.34 9.02 1.85 9.11 3.11 8.21 6.82 26.28

0.88 0.89 0.24 1.17 1.04 1.02 3.73 0.81 0.21 1.84

Aldrin (ng/g) 1.43 1.78 0.50 1.13 1.82 0.67 2.64 3.28 0.54 3.41

Endrin (ng/g)

Continued

6.03 6.24 0 0 5.84 3.71 7.23 16.57 0 0

Endosulfan Sulfate (ng/g)

*The value is the sum of all organochlorinated pesticides in the sediment (mg/kg, dry weight).

Deposition Date (y.m.)

Depth (cm)

Table 1.

5.35 3.40 3.13 7.07 4.97 3.51 2.29 2.16 3.22 0

Endrin Ketone (ng/g)


5.54 4.89 4.27 14.28 33.17 8.08 22.50 4.05 5.33 12.0

Methoxychlor (ng/g)

30.32 29.66 24.67 86.35 61.44 34.55 54.36 38.4 26.77 69.64

Total* (ng/g) ORDER REPRINTS

1880 KANG ET AL.

o, p0 -DDE

1.94 0.06 0.09 0.15 0.80 0.43 0.58 0.27 0.01 0.33 0.54 0.26 0.32 0.38 1.65 1.39 2.11 1.70 1.59 1.58 2.48 0.04 1.15 1.80 1.74

Depth (cm)

0–2 4–7 7–9 9–11 11–13 13–16 16–18 18–20 20–22 22–24 24–26 26–28 28–30 30–32 32–34 34–36 36–38 38–40 40–42 42–44 44–46 46–48 48–50 50–52 52–54

1.00 0.49 0.95 0.80 0.10 0.90 0.73 0.85 1.04 0.61 0.53 0.54 0.52 0.35 0.56 0.82 1.08 0.78 1.84 0.90 1.01 0.68 1.05 1.08 1.25

p,p0 -DDE 1.95 0.80 0.69 1.93 2.68 1.97 0.38 0.26 1.26 0.00 1.30 1.12 1.42 0.51 2.18 2.62 1.60 1.84 2.84 2.47 1.16 2.04 2.36 1.78 4.20

o, p0 -DDD 6.79 1.11 1.92 1.66 1.79 1.62 1.39 0.00 2.80 1.30 1.56 1.08 1.36 1.11 1.68 2.33 3.04 2.09 3.66 2.79 2.59 1.27 1.80 2.86 3.09

p, p0 -DDD 9.55 0.74 5.72 1.56 0.51 1.07 0.00 0.59 1.42 1.19 2.07 3.37 2.57 1.62 2.60 3.54 4.34 2.70 4.98 4.09 1.69 0.00 1.42 3.20 0.00

p, p0 -DDT 21.23 3.2 9.36 6.10 5.87 5.99 3.08 1.97 6.53 3.43 6.00 6.38 6.18 3.96 8.67 10.69 12.17 9.11 14.91 11.83 8.93 4.04 7.79 10.71 10.28

0.14 0.17 0.11 0.16 0.15 0.22 0.42 0.57 0.16 0.27 0.18 0.12 0.14 0.18 0.26 0.21 0.26 0.27 0.23 0.21 0.39 0.18 0.28 0.27 0.29

DDE/ DDTs 0.41 0.60 0.28 0.59 0.76 0.60 0.58 0.13 0.62 0.38 0.48 0.35 0.45 0.41 0.44 0.46 0.38 0.43 0.44 0.44 0.42 0.82 0.53 0.43 0.71

DDD/ DDTs 0.45 0.23 0.61 0.25 0.09 0.18 0.00 0.30 0.22 0.35 0.35 0.53 0.41 0.41 0.30 0.33 0.36 0.30 0.33 0.35 0.19 0.00 0.18 0.30 0

DDT/ DDTs 0.25 0.05 0.09 0.08 0.07 0.11 0.11 0.09 0.09 0.08 0.09 0.07 0.07 0.06 0.18 0.18 0.27 0.21 0.29 0.21 0.29 0.06 0.18 0.24 0.25

DDE/ DDT

Concentrations of DDT and Its Metabolites in Dated Core from Macao Estuary

DDT (ng/g dry wight)

Table 2.


0.827 0.733 0.898 0.866 0.922 0.745 0.730 0.851 0.802 0.851 0.788 0.726 0.703 0.782 0.738 0.786 0.721 0.755 0.715 0.769 0.744 0.851 0.842 0.849 0.979

Density (g/cm3)

ORGANOCHLORINE PESTICIDES IN SEDIMENTARY CORE (continued)

78.34 22.69 50.55 47.35 61.96 46.13 21.47 45.87 38.11 25.99 25.36 27.16 20.90 14.21 25.64 28.54 43.74 53.61 40.48 41.64 41.62 21.20 42.18 64.45 74.70

Flux* (ng/cm2.y)

ORDER REPRINTS

1881

1.08 3.20 2.77 14.1 3.85 1.83 2.27 1.07 2.34 2.73

54–56 56–58 58–60 60–62 62–64 64–66 66–68 68–70 70–72 73

0.96 1.28 1.11 2.99 1.32 0.97 1.67 1.74 1.17 2.04

p,p0 -DDE 2.50 1.32 2.68 9.51 3.28 2.53 5.15 5.60 2.19 0.42

o, p0 -DDD 2.37 2.96 4.29 8.93 5.72 4.18 4.32 4.95 3.83 7.99

p, p0 -DDD

DDT (ng/g dry wight)

8.54 1.75 2.21 3.61 3.85 2.65 5.21 2.41 0.76 2.00

p, p0 -DDT 15.45 10.50 13.05 39.13 18.03 12.16 18.61 17.64 10.30 15.19

Continued

*Fluxes (ng/cm2.y) ¼ density (g/cm3) deposition rate (cm/y) concentration (ng/g).

o, p0 -DDE

Depth (cm)

Table 2.

0.13 0.43 0.30 0.44 0.29 0.23 0.21 0.16 0.34 0.31

DDE/ DDTs 0.32 0.41 0.53 0.47 0.50 0.55 0.51 0.60 0.58 0.55

DDD/ DDTs 0.55 0.17 0.17 0.09 0.21 0.22 0.28 0.24 0.07 0.13

DDT/ DDTs


0.17 0.37 0.32 1.42 0.43 0.23 0.33 0.20 0.29 0.40

DDE/ DDT

0.996 0.834 0.818 0.915 0.954 0.911 0.404 0.833 1.011 0.64

Density (g/cm3)

67.71 56.00 37.74 147.75 120.02 65.17 46.53 85.63 50.61 78.66

Flux* (ng/cm2.y) ORDER REPRINTS

1882 KANG ET AL.

ORDER

REPRINTS

1883

core, heptachlor and its’ converted products was not detected, but the concentration and occurrence of methyoxychlor and endosulfan sulfate are in high values. The observed concentrations of DDTs in sediment core are shown in Table 2. Concentration variation of DDTs in sediment profile was more obvious than other compounds (Figure 3b). Concentrations of DDT and its derivatives, except for o, p0 -DDT, were higher than HCHs. A significant increase of concentration of DDTs occurred at the top and at depth of 60 cm, whose depositional time corresponded to 1964–1965. When normalized to sediment organic carbon (OC) (Figure 3c), highest concentration of DDTs was observed at top of the core. Higher concentration of DDTs in recent

HCHs

(a) 2000 1995 1990 Time, year

1985 1980 1975 1970 1965 1960 1955 0

20

40 60 Concentration,ng/g

80

100

Figure 3a. Veritical distributions of organochlorine pesticides (HCHs) with the time in a sedimentary core in Macao Estuary.

DDTs

(b) 2000 1995 1990 Time, year



1985 1980 1975 1970 1965 1960 1955 0

20

40

60

80

100

Concentration, ng/g

Figure 3b. Veritical distributions of organochlorine pesticides (DDTs) with the time in a sedimentary core in Macao Estuary.

ORDER

REPRINTS

1884

KANG ET AL. OCs Concentration,ug/(kg,TOC)

(c) 0

10

20

2000 1995 1990 Time,year

1985 1980 1975 1970 Downloaded By: [Zhejiang University] At: 08:11 20 November 2009

1965 1960 1955

Figure 3c. Veritical distributions of organochlorine pesticides (HCHs þ DDTs based on TOC) with the time in a sedimentary core in Macao Estuary.

sediment was an indication of new pollution sources in the area. One possible source could be from the discharges of Zhuhai Special Economic Zone, which was established recently. Since DDT residues are extremely persistent in the environment and their degradation depended strongly on the environmental conditions (4, 7, 14–16), the origins of DDTs in the sediment core could be traced based on the relative concentration of DDT and its derivatives. For example, DDT was reductively dechlorinated primarily to DDD under anaerobic environment and dehydrochlorinated to DDE under aerobic conditions (17). Therefore, DDD should be the dominant form in anaerobic conditions, such as in the sediment of Teltowkanal canal (18). Otherwise under aerobic conditions such as in contaminant soils, long-term weathering could result in higher concentrations of DDE and the ratio of DDE/DDT was usually more than unit. In the sediment core, the ratios of DDT to DDTs were mostly lower than 0.50 and the ratios of DDD/DDE during all intervals were more than unit. Concentrations of DDE were relatively constant, while concentrations of DDD showed much fluctuation in the core profile. Table 3 gives a comparison of ratio of DDT composition of sediment and it could be noted that ratio of DDE/DDT was lower than the reported ones, but closed to that in Xiamen bay (5). The dominated DDD residues in the core sediment clearly indicate that DDT was converted under almost anarobic conditons. Therefore, it was speculated that the organochlorine pesticides in the core were originated mainly from aged and the weathering agricultural soils (Table 2). Variations of the total concentration of HCHs and DDTs in the core profile could be explained based on water flux of Pearl River system. In Pearl

Xiamen Bay Reservoir Lake Michigan Lake Orta Corn Belt San Joaquin River Pearl River Delta Macao Estuary

Location

Table 3.

Core sediment Core sediment Surface sediment Core sediment Soil Bed sediment Surface sediment Core sediment

Sample Type DDE/DDTs DDT/DDTs DDE/DDTs DDE/DDT DDT/DDE DDE/DDT DDD+DDE/DDT DDE/DDTs

Reported Ratios 0.04–0.36 0.47–0.78 0.61–0.71 0.53–5.32 0.5–2 (>5) 2.3–8.8 0.9–3.6 0.04–0.37

Concentration (ng/g)

[5] Chen, et al., 1996 [4] Metre, et al., 1997 [22] Choi and Chen, 1976 [23] Guzzella, 1997 [24] Aiger, et al., 1998 [25] Pereira, et al, 1996 Our laboratory (not published) This study

References

The Literature Reported Ratios Between DDT and Its Metabolites in Comparison with the Present Work


ORDER REPRINTS

ORGANOCHLORINE PESTICIDES IN SEDIMENTARY CORE 1885

ORDER

REPRINTS

1886

KANG ET AL.


Rive estuary, the particle loading was contributed by three rivers, i.e., the Zhu River, the North River and the West River (Figure 1). The loading via Macao Estuary accounted for 87% of sand and 64.5–80.0% of suspending matters in Pearl River. The hydrological data showed that there were a total of 5 flood years and 5 drought years in the last 50 years (19). As shown in Figure 5, there was a good agreement between water fluxes (Figure 4) and

Figure 4.

Changes of water fluxes of Pearl River with the time.

deposition fluxes 2000 1995 1990 Time, year

1985 1980 1975 1970 1965 1960 1955 0

Figure 5.

50

100 Flux, ng/cm2.y

150

200

Fluxes of organochlorine pesticides in sediment core in Macao Estuary.

1 2 2 3 na* 0.02

Effect-range-low (ERL) (ng/g Dry Weight) 7 20 15 350 na* 45

Effect-range-median (ERM) (ng/g Dry Weight) 0.51–9.55 (2.72) 0.26–18.44 (5.11) 0.55–17.1 (2.82) 3.08–21.23 (10.53) 0.24–4.83 (1.02) 0.28–3.41 (0.75)

Concentration Range (Mean)** (ng/g Dry Weight)

9.55 8.74 2.94 21.23 4.83 1.50

Surface Sediment of the Core (0–2 cm) (ng/g Dry Weight)

Comparison of Concentrations of Chlorinated Pesticides in Core from Macao Estuary to the Sediment Quality Guidelines (20)

Note: Grades: < ERL, rare; ERL-ERM, occasionally; > ERM, frequently. *Not available; **Values in brackets is mean.

DDT DDD DDE DDTs Aldrin Endrin

Chemical

Table 4.


ORDER REPRINTS

ORGANOCHLORINE PESTICIDES IN SEDIMENTARY CORE 1887

ORDER

REPRINTS

1888

KANG ET AL.


concentrations of HCHs þ DDTs in the sediment. Larger water fluxes corresponded to higher loading of pesticides. Therefore, it could be expected that the input of suspended matters from Pearl River should be the major cause to the concentration variation of pesticides in the core sample. While the fluxes of organochlorinate pesticides in the core varied with time (Figure 5), the maximal concentrations appeared during 1965.

Risk Assessment for Organochlorine Pesticides in the Core Sediment Long et al. (20) proposed guidelines based on the data from 89 reports that contain chemical data and simultaneous measures of biological effects. They separated concentrations into those that are ‘‘rarely’’, ‘‘occasionally’’ and ‘‘frequently’’ associated with biological effects. The critical concentrations defining these categories are the 10th and 50th percentiles of concentrations associated with effects. These percentiles are designated the ERL (Effects Range Low) and ERM (Effects Range Median), respectively. Concentrations of the organochlorine pesticides in the core from Macao Estuary could be assessed based the guidelines (Table 4). It could be noted that the concentrations of DDT, DDD, DDE and DDTs were all above the effectrange-low (ERL) values and part of them were higher than the effect-rangemedian (ERM) values. It was speculated that there were potential adverse biological effects of organic contaminants in sediments (23).

CONCLUSION Concentrations of organochlorine pesticides in sediment core from Macao Estuary are reported. The sediment core records of the pollution history of organochlorine pesticides in the area were reconstructed. It was found that the concentrations variations of pesticides in sediment core profile varied with water fluxes of the Pearl River system and the major source of pollution was from the surface runoff in nearby area. The concentrations of DDT, DDD, DDE and DDTs were all above the effect-range-low (ERL) values.

ACKNOWLEDGMENTS This research was funded by the National Scientific Foundation of China (4972026) and part of the work was supported by Research Center for Eco-environmental Sciences (RCEES-KIP-9901).

ORDER

REPRINTS


1889


REFERENCES 1. Hua, X.M.; Shan, Z.J. The production and application of pesticides and factor analysis of their pollution in environment in China. Adv. Environ. Sci., 1996, 4(2), 33–45. (in Chinese). 2. Cai, F.L.; Lin, Z.F.; Chen, Y.; Yang, J.D. The study on the behavior character of BHC and DDT in the tropical marine environment. Marine Environmental Science, 1997, 16(2), 9–14. (in Chinese) 3. Latimer, J.S.; Quinn, J.G. Historical trends and current inputs of hrdrophobilic organic compounds in an urban eatuary: the sediment record. Environ. Sci. Technol., 1996, 30(2), 623–633. 4. Meter, P.C.V.; Callender, E.; Fuller, C. Historical trends in organochlorine compounds in river basin identified using sediment cores from reserviors. Environ. Sci. Technol., 1997, 31, 2339–2344. 5. Chen, W.Q.; Zhang, L.P.; Xu, L.; Wang, X.H.; Hong, H.S. Vertical distribution characteristics of chlorinated pesticides and polychlorinated biphenyls in sediments of Xiamen Bay. Marine Science, 1996, 2, 56–60. (in Chinese) 6. Chen, J.F.; Ye, X.R.; Zhou, H.Y.; Xia, X.M.; Zheng, S.L. Preliminary study on the marine organic pollution history in Changjiang Estuary-Hangzhou BayBHC and DDT stratigraphical records. China Environmental Science, 1999, 19(3), 206–210. (in Chinese) 7. Donald, D.B.; Syrginnis, J.; Crosley, R.W. Delayed deposition of organochlorine pesticides at a Temperate Glacier. Environ. Sci. Technol., 1999, 33(11), 1794–1798. 8. Lin, R.F.; Min, Y.S.; Wei, K.Q.; Zhang, G.; Yu, F.J.; Yu, Y.L. 210Pb-Dating of sediment cores from the Pearl River Mouth and its environmental geochemistry implication. Geochima, 1998, 27(5), 401–411. (in Chinese). 9. Lin, Z.; Mai, B.X.; Zhang, G.; Sheng, G.Y.; Min, Y.S.; Fu, J.M. Quality assurance/quality control in quantitative analysis of polycyclic aromatic hydrocarbons and organochlorine pesticides in sediments. Environmental Chemistry, 1999, 18(2), 115–121. (in Chinese). 10. Liao, Q. Investigation of the residue of pesticides (BHC, DDT) in sea water, sediments and organisms along the East coast of Guangdong. Marine Environmental Science, 1986, 5(2), 8–14. (in Chinese). 11. Willett, K.L.; Ulrich, E.M.; Hites, R.A. Differential Toxicity and Environmental fates of Hexachlorocyclohexane isomer. Environ. Sci. Technol., 1998, 32(15), 2197–2207. 12. Walker, K.; Vallero, D.A.; Lewis, R.G. Factors influencing the distribution of Lindane and other hexachlorocyclehexanes in the environment. Environ. Sci. Technol., 1999, 33(24), 4373–4378. 13. Ayas Zafer; Barlas Nurhayat; Kolankaya Durdane. Determination of organochlorine pesticide residues in various environments and organisms in Goksu Delta, Turkey. Aquatic Toxicology, 1997, 39, 171–181. 14. Munn, M.D.; Gruber, S.J. The relationship between land use and organochlorine compounds in streambed sediments and fish in the central Columbia Plateau, Washington and Idaho, USA. Environmental Toxicology and Chemistry, 1997, 16(9), 1877–1887.

ORDER


1890

REPRINTS

KANG ET AL.

15. Sarkar, A.; Nagarajan, R.; Chaphadkar, S.; Pal, S.; Sigbal, S.Y.S. Contamination of organochlorine pesticides in sediments from Arabian Sea along west coast of India. Wat. Res., 1997, 31(2), 195–200. 16. Bergquist, P.A.; Stradberg, B.; Ekelund, R.; Rappe, C.; Granmo, A. Temporal monitoring of organochlorine compounds in seawater by semipermeable memberanes following episode in Western Europe, Environ. Sci. Technol., 1998, 32(24), 3887–3892. 17. Hitch, R.K.; Day, H.P. Unusual persistence of DDT in some Western USA soils. Bull. Environ. Contam. Toxicol., 1992, 48, 255–264. 18. Heberer, T.; Dunnbier, U. DDT metabolite Bis(chlorophenyl)acetic acid: the neglected environmental contaminant. Environ. Sci. Technol., 1999, 33(14), 2346–2351. 19. Chen, T.G.; Yang, Q.S. The influence of water fluxes of Peal River to the sealevel in Estuary Area in the last 40 years. Research and Development of South China Sea, 1998, 3/4, 12–18. (in Chinese). 20. Long, E.R.; Macdonald, D.D.; Smith, S.L. Incidence of adverse biological effects with ranges of chemicals concentrations in marine and esruarine sediments. Environmental Management, 1995, 19(1), 81–97. 21. Kennlcutt, M.C.; Wade, T.L.; Persley, B.J.; Requejo, A.G.; Brooks, J.M.; Denoux, G.J. Sediment contaminants in Casco Bay, Maine: Inventories, sources and potential for biological impacts. Environ. Sci. Technol., 1994, 28(1), 1–15. 22. Choi, W.N.; Chen, K.Y. Association of chlorinated hydrocarbons with fine particles and humic substances in nearshore surficial sediments. Environ. Sci. Technol., 1976, 10, 782. 23. Guzzella, L. PCBs and organochlorine pesticides in Lake Orta (Northern Italy) sediments. Water, air and soil pollution, 1997, 99, 245–254. 24. Aigner, E.J.; Leone, A.D.; Falconer, R.L. Concentrations and enantimeric ratios of organochlorine pesticides in soil from the U.S. Corn Belt. Environ. Sci. Technol., 1998, 32, 1162–1168. 25. Pereira, W.E.; Domagalski, J.L.; Hostettler, F.D. Occurrence and accumlation of pesticides and organic contaminants in river sediment, water and calm tissues from the San Joaquin River and tributaries, California. Environmental Toxicology and Chemistry, 1996, 15, 172–180. Received May 1, 2001

Request Permission or Order Reprints Instantly! Interested in copying and sharing this article? In most cases, U.S. Copyright Law requires that you get permission from the article’s rightsholder before using copyrighted content.


All information and materials found in this article, including but not limited to text, trademarks, patents, logos, graphics and images (the "Materials"), are the copyrighted works and other forms of intellectual property of Marcel Dekker, Inc., or its licensors. All rights not expressly granted are reserved. Get permission to lawfully reproduce and distribute the Materials or order reprints quickly and painlessly. Simply click on the "Request Permission/Reprints Here" link below and follow the instructions. Visit the U.S. Copyright Office for information on Fair Use limitations of U.S. copyright law. Please refer to The Association of American Publishers’ (AAP) website for guidelines on Fair Use in the Classroom. The Materials are for your personal use only and cannot be reformatted, reposted, resold or distributed by electronic means or otherwise without permission from Marcel Dekker, Inc. Marcel Dekker, Inc. grants you the limited right to display the Materials only on your personal computer or personal wireless device, and to copy and download single copies of such Materials provided that any copyright, trademark or other notice appearing on such Materials is also retained by, displayed, copied or downloaded as part of the Materials and is not removed or obscured, and provided you do not edit, modify, alter or enhance the Materials. Please refer to our Website User Agreement for more details.

Order now! Reprints of this article can also be ordered at http://www.dekker.com/servlet/product/DOI/101081ESE100107435