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HEALTH CONSULTATION

CALCASIEU PARISH (CALCASIEU ESTUARY)
LAKE CHARLES, CALCASIEU PARISH, LOUISIANA


BACKGROUND AND STATEMENT OF ISSUES

The U. S. Environmental Protection Agency-Region VI (EPA) asked the Agency for Toxic Substances and Disease Registry (ATSDR) to evaluate environmental contamination data and blood biomonitoring data from Calcasieu Parish, Louisiana.

The Calcasieu Estuary area is an industrialized area where several petrochemical and agrochemical plants manufacture and process diverse products such as petroleum, sodium hydroxide, chlorine, teflon, butadiene, synthetic rubber, vinyl chloride, trichloroethylene, and perchloroethylene. Within Calcasieu Parish, 153 releases of oil and hazardous materials were reported to the National Response Center from October 1996 to September 1997. The EPA is investigating the impact of such releases on the ecology and human health in the Calcasieu Estuary area.

A resident of Calcasieu Parish provided ATSDR with analytical data for 12 blood samples, 9 sediment samples, and 1 composite clam sample. Ergo Forschungsgesellschaft mbH in Hamburg, Germany analyzed the samples for chlorinated dibenzodioxins (CDDs), chlorinated dibenzofurans (CDFs), and co-planar polychlorinated biphenyls (IUPAC congeners 77, 126, and 169). This group of chemicals is often referred to by the generic term, "dioxin," since these chemicals exert a toxic action similar to the most toxic chemical in the group, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

In order to assess the health impact of a mixture of dioxin-like compounds, risk assessors often convert the toxicity of individual congeners to TCDD equivalents (TEQs) using Toxicity Equivalent Factors (TEFs) [1]. The toxicity of the mixture is then assumed to be the sum of the individual components. The concentrations of TCDD and TEQs in the blood samples from Calcasieu Parish are presented below in Table 1.

According to the citizen who provided the laboratory data to ATSDR, one of the blood samples ("Calcasien background") was a pooled blood sample obtained from 100 patients at St. Patrick's Hospital in Lake Charles. The other 11 blood samples were from individuals who were selected because: (1) they had a disease that has been associated with dioxin (e.g., non-Hodgkin's lymphoma, endometriosis) or (2) they were at risk for increased exposure (e.g., high fish and shellfish consumption, living near an incinerator, or working in a chemical factory).

The blood and sediment samples were also analyzed for nine selected PCB congeners. Five of these congeners were apparently selected because they are marker constituents of commercial PCB products (e.g., Aroclor 1016, 1254, 1260). The other three congeners (IUPAC 105, 118, and 156) are mono-ortho-substituted PCBs that have some dioxin like activity. The concentrations of these PCBs were reported as mg/kg in blood, so they can not be combined with the other dioxin congeners, which were reported as pg/g blood lipid. However, the TEQ total would not be significantly affected if the mono-ortho-substituted PCBs were not included, because their concentrations were low, and they have low TEF values.

 

Table 1.

Blood serum concentrations of TCDD and dioxin-like compounds (pg/g lipid)
Sample TCDDa TEQsb TEQs+PCBsc
1 (pooled) 10.4 45.9 53.2
2

6.2

34.3

44.2

3

7.0

45.2

52.7

4

15.3

94.1

103.7

5

6.8

38.7

43.4

6

3.4

20.1

24.5

7

2.6

11.2

16.5

8

3.2

14.9

19.3

9

3.8

18.1

21.6

10

8.3

62.2

79.2

11

2.1

14.1

19.5

12

1.5

7.4

9.8

Reference
Range

3.2-10.1d

28-41e

36-58e

a - 2,3,7,8-tetrachlorodibenzo-p-dioxin
b - TCDD + other CDDs and CDFs
c - TCDD + other CDDs and CDFs + co-planar PCBs
d - range of means from selected reference studies [2]
e - average background range in the general population [3]

Values in bold type exceed the reference range.

 

Table 2.

Dioxin Concentrations in Blood Serum (pg/g lipid) from resident with the highest dioxin TEQs+PCBs
Chemical Resident Reference 1
2,3,7,8-Tetrachlorodibenzo-p-dioxin 15.3 3.2-10.1
1,2,3,7,8-Pentachlorodibenzo-p-dioxin

54 6.6-32
1,2,3,4,7,8-Hexachlorodibenzo-p-dioxin

100 6.3-13
1,2,3,6,7,8-Hexachlorodibenzo-p-dioxin 142.8 45-85
1,2,3,7,8,9-Hexachlorodibenzo-p-dioxin 28.9 7.1-21.9
1,2,3,4,6,7,8-Heptachlordibenzo-p-dioxin 313.7 80.3-230
Octachlorodibenzodioxin 1899.8 560-1000
2,3,7,8-Tetrachlorodibenzofuran 1.7 1.1-9
1,2,3,7,8-Pentachlorodibenzofuran <2.1 ND
2,3,4,7,8-Pentachlorodibenzofuran 21.8 5-27
1,2,3,4,7,8-Hexachlorodibenzofuran 38.7 4.5-11
1,2,3,6,7,8-Hexachlorodibenzofuran 29.0 4.5-8.5
1,2,3,7,8,9-Hexachlorodibenzofuran ND ND
2,3,4,6,7,8-Hexachlorodibenzofuran 12 ND
1,2,3,4,6,7,8-Heptachlorodibenzofuran 56.8 8.7-22.8
1,2,3,4,7,8,9-Heptachlorodibenzofuran <1.4 ND
Octachlorodibenzofuran <5 ND
3,3',4,4'-Tetrachlorobiphenyl <20 11.7
3,4,4',5-Tetrachlorobiphenyl ND 10.5
3,3',4,4',5-Pentachlorobiphenyl 87.7 135
3,3',4,4',5,5'-Hexachlorobiphenyl 80.1 69

ND - not detected
Reference 1 - range of means (pg/g lipid) from selected reference studies [2]
Values in bold type exceed the reference range.

 

 Sediment

Sediment samples from nine locations contained dioxin TEQ concentrations ranging from 0.0023 to 2.958 parts per billion (ppb) dry weight. Only one sediment sample exceeded 1 ppb; this sample was collected at the north edge of Bayou d'Inde.

Biota

A composite clam sample was collected just outside the swimming buoy line at the southeast end of North Beach on Lake Charles. The dioxin TEQs in this sample were reported as 51.6 parts per trillion (ppt) "fat based." According to the U.S. Department of Agriculture, clams contain 0.456 percent fat [4]; therefore, on a wet weight basis, the clams contained 0.24 ppt dioxin TEQs.


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