Recent measures to further reduce dioxin impact on man and the environment in the Federal Republic of Germany

Chemosphere,Vol. 29, Nos. 9--11, pp. 2439-2454, 1994

Pergamon

Elsevier Science Ltd Printed in Great Britain 0045-6535/94 $7.00+0.00

0045-6535(94)00292-4

RECENT MEASURES TO FURTHER REDUCE DIOXlN IMPACT ON MAN AND THE ENVIRONMENT IN THE FEDERAL REPUBLIC OF GERMANY

Schulz, D. Federal Environmental Agency, P.O. Box 330022, D-14191 Berlin, Germany Keywords:

PCDD/PCDF,

regulations,

limit values,

measures,

chemicals,

milk,

Germany

ABSTRACT During last year's Dioxin symposium at Tampere/Finnland a report was given on the legislative actions of the German Federal Goverment to reduce dioxin release into the environment (1). Since then, further progress has been made, especially to regulate chemicals and to establish orientation values for PCDD/F in cow's

milk. An

international dioxin symposium and hearing was held in Berlin in November 1992, which focussed on the scientific base for legislative and other governmental action to minimize dioxin burden on man and the environment. Measurements from different media including breast milk indicate a decrease in dioxin release into the environment during the last several years in Germany.

INTRODUCTION After an international dioxin symposium and hearing in Karlsruhe/Germany in 1990 (2,3,4,5) the following preliminary concept for tolerable daily intake values has been developed for Germany: - value of precaution 1 pg TEQ/kg body weight (b.w.): human health implications can be excluded with high probability. - range of risk 1 - 10 pg TEQ/kg b.w.: no health implications assumed, but no sufficient safety margin based on principles of preventive health protection. Measures are necessary to minimize dioxin release into the environment.

2439

2440 - value of intervention 10 pg TEQ/kg b.w.: if daily dioxin intake exceeds this value for longer periods, immediate actions are necessary.

M E A S U R E S TO REDUCE DIOXIN I M P A C T TAKEN IN 1 9 9 2 / 9 3 Ordinance on Dioxins The

Ordinance

on

Dioxins

(Dioxin-Verordnung)

prohibits

placing

substances,

preparations and articles on the market, if the following limit values are exeeded (sum of concentration, not TEQ): 1 ppb for 2,3,7,8-TCDD and 1,2,3,7,8-PeCDD and 2,3,7,8-TCDF and 2,3,4,7,8PeCDF. 5 ppb for 12 2,3,7,8-substituted congeners (tetra- to hexa-congeners, "dirty dozen"). - 100 ppb for all 17 congeners substituted in 2,3,7,8-position. limit values for PBDD/PBDF: 1 ppb for 2,3,7,8-TBDD and 1,2,3,7,8-PeBDD and 2,3,7,8-TBDF and 2,3,4,7,8PeBDF. 5 ppb for the 4 congeners above and 1,2,3,4,7,8-HxBDD, 1,2,3,7,8,9-HxBDD, 1,2,3,6,7,8-HXBDD and 1,2,3,7,8-PeBDF. For intermediate substances (i.e. substances which are bound to be interconverted by a chemical process) the prohibitions do not apply. Instead a notification requirement has been newly included into this ordinace if the mentioned dioxin concentrations are exceeded. Within the notification processs persons trading with intermediates exceeding the limit values are obliged to indicate to the competent authorities: - the trade name of the intermediate - the concentrations of the 17 PCDD/PCDF as well as the 8 PBDD/PBDF-congeners

2441

- the total amount of intermediates sold. The person obliged to submit a notification shall in addition announce in the first notification the name and adress of the domestic company to which the intermediate substances are sold and, upon request of the competent authority, include into following notifications an appropriately updated list. The Ordinance on Dioxins does not apply for certain products w h i c h are already regulated by other laws such as - tobacco products, cosmetics (regulated by Foodstuffs and Commodities Act - Lebensmittels- und Bedarfsgegenstiinde-Gesetz) or drugs (regulated by the Law governing the Manufacture and Prescription of Drugs - Arzneimittelgesetz) - pesticides (regulated by the Plant Protection Act - Pflanzenschutzgesetz) substances and preparations used for the extraction of non-ferrous metals in installations subject to licensing according to the Federal Immission Control Act (Bundesimmissionsschutzgesetz). - marketing for a duly disposal of wastes. A three year transition period (during which the current limit values of the Ordinance on Dangerous Substances - Gefahrstoffverordnung - must be met) was set for - anthrachinoid pigments - dyestuffs and pigments which are produced with chloranil 1 as intermediate

-

substances, preparations and products which do not exceed the following limits: -

3 ppb for the sum of 4 tetra- and penta-congeners 2

- 20 ppb for the "dirty dozen" Furthermore chloranil ist regarded as an intermediate for three years, if it is used as a catalyst in the production of dyes and pigments.

1 chloranil

= 2,3,5,6-Tetrachloro-l,4-benzoquinone

2 2,3,7,8-TCDD,

2,3,7,8-TCDF,

1,2,3,7,8-PeCDD

and 2 , 3 , 4 , 7 , 8 - P e C D F .

2442 Two major product groups which were supposed to contain considerable amounts of dioxin impurities due to the manufacturing process are dioxazine and phthalocyanine pigments used as textile dyes. During the preparation of the Ordinance on Dioxins it was highly controversial discussed whether these products could meet the new strict limit values. Analyses of commercial chloranils produced in the USA had shown high contents of hepta- and octachlorodioxins and - furans (6). Laboratory experiments (7) had placed the production of chlorophenols and derivates on the highest priority amongst a vast range of industrial processes for probable dioxin formation. Further investigations had shown possibilities to avoid dioxin formation by process-oriented measures (8). According to the Chemicals Act (ChemG. §§ 6 and 16) the chemical industry must provide data on dioxin contents of new substances within the German Limited Announcement. Such data are basically confidential, so no details can be given here. A rough classification of data provided by major national and international companies before

July

1993

on

PCDD/PCDF-impurities of dioxazine and phthalocyanine

pigments in relation to limit values of the Ordinance on Dioxins showed the results presented in Table 1.

dioxazines

phthalocyanines

(including chloranil) n=15 below

n=15 above limit

Z4

15

0

(limit 1 ppb)

range 0.05 - 0.8

~-12

11

(limit 5 ppb)

range < 1 . 2 - < 22

4

Z17

3

(limit 100 ppb)

range 3.7 - 3 700

12

below 15

above limit 0

range 0.08-0.8 15

0

range 0.3 - 2.4 14

1

range < 4-140

Table 1. Dioxin impurities in dyes in relation to limit values of the Ordinance on Dioxins.

2443 As the table shows the new limit values set by the Ordinance on Dioxins can be met. For chloranil e.g. the production process was recently changed. Until 1990 chloranil was produced by chlorination and oxidation of phenol by a 2-step process with 2,4,6-trichlorophenol as an intermediate. This process has been abandoned in Germany. Modern processes start with hydroquinone, giving a much "cleaner" product. 3

Orientation values for P C D D / P C D F in milk

In 1991 the Joint Working Group of the Federation and the L~nder (federal states) on Dioxins recommended several reference values for dioxins in soils depending on their use (1,9). It was recommended that at soil contents between 5 and 40 ng TEQ/kg the possibility of increased dioxin transfer (e.g. into cows milk or eggs) should be analyzed. Especially milk from grazing cattle is regarded as a suitable indicator for extensive soil contamination and possible dioxin impact on the food chain. Food and foodstuff have been analyzed for PCDD/PCDF since 1986. Altogether about 900 analyses have been performed, the majority on milk and dairy products. Yet there are some problems in summarizing and assessing these data: - little data has been collected during investigations on the general background of

PCDD/PCDF in food and foodstuff. Most data were gained in order to explain observed high dioxin levels or to clarify cases of alleged dioxin contamination of food (i.e. the values are not representative and probably too high). sampling and clean-up procedures have changed during the last seven years, statistical evaluation varied and n.d. values for single congeners were sometimes neglected, sometimes included as half or full detection limit when reporting for TEQ. To provide comparable data in the future a subgroup "measuring programmes" of the Joint Working Group elaborated suggestions for harmonized methods and published the suggestions within its final report (10).

3 f o o t n o t e : all r e g u l a t i o n s of the f o r m e r l y p l a n n e d o r d i n a n c e o n d i o x i n s h a v e m e a n w h i l e b e e n set i n t o f o r c e n o t in a n o w n o r d i n a n c e , b u t w i t h i n the f i r s t a m e n d m e n t of the O r d i n a n c e o n t h e B a n of C h e m i c a l s (21) .

2444

In spite of the problems described, the data on PCDD/PCDF in milk and dairy products in the Federal Republic of Germany can be summarized (not meeting scientific standards, but providing valuable information for environmental politics) as follows (Table 2; from Ref. 11): Table 2: PCDD/PCDF content of milk and dairy products in the FRG (in pg TEQ/g fat).

PCDD/PCDF in pg TEQ/g fat (I-TEQ) n

rain

max

~ilk collected on single farms

178

0,31

3,81

1,09

milk collected in tanks

34

0,14

1,68

0,76

415

0,14

3,81

0,95

dairy products

mean

Maximum tolerable values (H6chstwerte) for the contamination of food and foodstuff can be derived in a theoretical manner from the above mentioned TDIvalues of precaution (1 pg TEQ/kg b.w.) resp. intervention (10 pg TEQ/kg b.w.) and daily consumed amounts of food and their dioxin contents. Based on data on dioxin concentration in food and daily food consumption maximum values can be calculated as shown in Table 3.

Table 3: Calculated maximum values for PCDD/PCDF in milkfat. male adult

female adult

(36 - 50 a)

(36 - 50 a)

body weight

70 kg

58 kg

daily milkfat consume

31,2 g

32,5 g

% of total daily dioxin uptake

36 %

42 %

8.1 pg TEQ/g

7,5 pg TEQ/g

0,8 pg TEQ/g

0,8 pg TEQ/g

taken up via milkfat maximum value for dioxins in milkfat, -

based on intervention level (TDI = lOpg TEQ/kg b.w.)

-

based onlevel of precaution (TDI = 1 pg TEQ/kg b.w.)

b.w. x TDI x percent of total uptake Calculation: max. value 100 x milkfat consumed

2445 From the data shown in Table 2 on the existing dioxin contents of milk it is obvious, that a limit value of about 8 pg TEQ/g milkfat would only cut off cases of extreme contamination. The highest value measured in milk collected on single farms in Germany was 5.9 pg TEQ/g fat. Thus a limit value of about 8 pg TEQ/g fat would probably have no consequences at all and would not improve the consumer's situation. The 37th Conference of Ministers for the Environment in Germany in November 1991 appointed the Joint Working Group of the Federation and the Liinder (federal states) on Dioxins to elaborate orientation and limit values based on the principle of precaution. Therefore a TDI-value of 1 pg TEQ/kg b.w. (value of precaution) is to be taken as basis for orientation values and the current contamination of food and foodstuff hat to be reduced by approx. 50 %. Thus the target value for milk and dairy products would be about 0,8 pg TEQ/g fat. From the data presented above (Table 2) it is obvious that more than 50 % of milk and dairy products in Germany currently exceed this value, A similar situation for other relevant food can be expected under similar prerequisites. Which consequences for environmental politics can be drawn out of this situation? The Joint Working Group of the Federation and the l~inder on Dioxins came to the conclusion that

-

an immediate implementation of the value of precaution (1 pg TEQ/kg b.w.) into maximum amounts (H6chstmengen) for food would lead to non assessable consequences in respect to the food supply of the population as well as to economic difficulties

-

-

the values should be regarded as target values to be achieved to reach this target all dioxin releases into the environment are to be minimized, as this is the only promising way to reduce food contamination and human body burden - the establishment of a limit value for dioxins in food (according to § 9 Abs. 4 Foodstuff and Commodities Act -Lebensmittel- und Bedarfsgegenst~ndegesetz) based on the value of intervention (10 pg TEQ/kg b.w.) only would cut off peak contaminations and is therefore not a suitable way to reduce daily human uptake of dioxins to less than 1 pg TEQ/kg b.w.

2446 In the end the group came to the graded concept of action shown in Table 4. This concept still has to be approved by the conference of ministers for the environment.

PCDD/PCDF-contamination

recommended action

pg TEQ/g milk fat < 0.9

target value to be met. Only to be achieved by long-term reduction of PCDD/PCDF release into the environment im

investigate sources and start measures

> 3.0

to minimize release. If no short term measures to reduce emissions are possible, it is recommended to the farm to change pattern of land use. Recommendation not to distribute milk and dairy products directly to the consumer. > 5.0 Table

milk and dairy products no longer marketable. 4:

proposed

orientation

values

for

PCDD/PCDF

in

milk

fat

and

recommended actions in the FRG (11).

International dioxin symposium and hearing of the Federal Health Office and the Federal Environmental Agency in Berlin, Nov. 1992. Under the auspices of the Federal Minister for the Environment, Nature Conservation and Nuclear Safety and the L~nder (federal states) Berlin and Brandenburg an international dioxin symposium and hearing was held in Berlin in November 1992. The purpose of the event was to provide a better scientific base for further legislative and other governmental activities to minimize dioxin burden on man and the environment in the Federal Republic of Germany. The Federal Health Office (FHO) and the Federal Environmental Agency (FEA) had prepared a catalogue of questions for the hearing and had asked internationally known experts for written statements on selected questions.

2447

The proceedings of the symposium were published by The Toxicology Forum (12). The publications of the written expert statements as well as the verbatim protocol of the hearing are currently prepared by the FEA (13) and the FHO (14). A first report on conclusions from the symposium and hearing was prepared by both authorities and was published by the FHO (1 5). An English version is being prepared by the FEA (16). Some of the basic conclusions in the field of environmental protection are: whereas in the past the chemical industry (including pulp and paper) was generally

-

considered

to

contaminated information

be

the

main

source

and

cause

for

todays

abandoned

sites in Germany it can be assumed due to the

that the new,

particularly atmospheric

inputs of

available

PCDD/F are

nowadays mainly caused by thermal processes. According to deposition data annual dioxin deposition in former West Germany can be estimated to 1 - 2 kg TEQ. - the magnitude of secondary sources (i.e. former emissions which now circulate in the biosphere) is still very difficult to estimate. They are not included in the estimation above. - sediment analyses show that the highest 2,3,7,8-TCDD-contents can be ascribed to the deposit areas of the late sixties. The current level decreased to values of the forties. A

working

group

of

the

Immission

Protection

Committee

of

the

L~nder

(L~nderausschul~ f~3r Immissionsschutz) prepared a report on dioxin emissions from plants other than MWls (e.g. metal recycling plants, steel mills etc.) to examine whether a limit value of 0.1 ng TEQ/m 3 in exhaust gases (as valid for MWls in Germany) can be met by other plants (17). The working group collected emission data and elaborated recommendations for further measures to minimize dioxin emissions. The results can be summarized as follows: - most currently available emission data are given as concentrations (pg/m 3 etc.). To assess the importance of single source groups mass flows would be necessary. In most cases data are lacking for such an estimation. emissions from power stations and furnaces for the use of fuel oil or gas are considerably less than 0,1 ng TEQ/m 3. The same is to be expected for the use of coal in furnaces.

2448 - furnaces for the combustion of wood have to be regarded in relation to fuel, firing process, exhaust gas processing and purification techniques. If untreated wood is burnt in modern furnaces with good burn out ratios, good exhaust gas processing and effective dust elimination (e.g. with fabric filters or electrofilters) an emission value of 0.1 ng TEQ/m 3 can be met in the exhaust gas. On the other hand, if wood coated with halogenorganic materials (e.g. PVC), treated with chlorine based compounds or PCP, lindane, etc. is burnt elevated dioxin emissions up to 10 ng TEQ/m 3 can be measured. To minimize emissions various primary and secondary measures are suitable, which cannot be specified here.

DECREASE OF ENVIRONMENTAL POLLUTION BY PCDD/PCDF IN GERMANY DURING RECENT YEARS Data on AOX-content of the Rhine water, dioxin concentrations in sediment cores, dioxin immission concentrations in Hessen and dioxin concentration in breast milk of women from Northrhine Westphalia indicate a decrease of dioxin release into the environment in Germany as a result of the described above measures. For example, AOX (adsorbable organic halogen) has been monitored in the Rhine River water near Koblenz since 1986 to get information on the total organic chlorine content in surface waters (the Rhine at this location already contains about 80 % of its total AOX burden) The data are shown in Figure 1 (from 19).

11

T

_

m

m

1°~--11

total burden

r-7 industrial burden

m

"0 8-

t-

7"

"0

6"

.Q

5"

!

X O < OI

~ 1986

,

i

1987

1988

i

1989

•

1990

IS~)1

Fig. 1. Decrease of chloroorganic compounds in the Rhine River.

2449

According to our present knowledge the decrease in AOX burden is mainly due to technical measures in the pulp and paper industry (conversion from chlorine bleaching to oxygen bleaching).Thus it can also be assumed that the PCDD/PCDF burden of the Rhine River has been reduced parallel to AOX. A decrease of dioxin burdens of surface waters is also shown by sediment core analyses performed

in The

Netherlands

(from

Ref.

13).

Data

presented

by

BEURSKENS during the Berlin Symposium in 1992 on PCDD/PCDF content in Lake Ketelmeer sediments (one of the sedimentation areas of the Rhine River in the Netherlands with

no major

point sources nearby)

revealed that the

highest

concentrations of the lower chlorinated dioxins were found in layers that were deposited in the 1960's and 1970's. 2,3,7,8-TCDD reached concentrations up to 400 ng TEQ/kg in the late 1960's (Fig 2a,b). Overall dioxin sedimentation in the 1990's corresponds to the level between 1 940 and 1950.

Concentration (in ng/kg)

Concentration (in ng]kg) 5o0 2.3,7,8-TC00

1400o

OCOD o 12000

100(]0

8OOO

,

',

•

•

6O0O

•

,

4OOO

ot

•

0.,,"" 0 0 1#

/

; #

20OO

0

, ,,,e,,'-~. ~ ~

~

0

¢,.'".\ o o~" o',

t t

#

0

t

o

,

1930 ~SMO 1950 1960 1970 lSeO 1 ~ 0

- ~"~'~

. . . . . .

U%RJ

Year of deposition

Year of deposition 0 : secrzmentcoresatnlPle,takenin 1990 • : s~imen~top I~jer sample,takenin 1972

Fig. 2a. Dioxin concentration of Rhine River sediments in The Netherlands.

o~

2450

Concentration (in ng/kg)

Concentration (in ng/kg) ~0(x)

35o

2.3,7,8-TCOF

OCDF

•

3OOOO

3oo

250OO

2so

O G

2O00O

2oo

0 0

O

15o

9'

! 1oo

0~30

a

sS

I

10000

'°~ O

e

a

•

&

i

0

Ooe..

15000

o*\

!

1940 1950 1960

.

T 1970

•

I

•

; tb

\

s

lgeO 1990 2000

Year of deposition

Year of deposition o : sKlime~ core sample, laken in 1~ 0

• : sedimemtop layersample,tak~ b 1972

Fig. 2b. Furane Concentration of Rhine River sediments in The Netherlands. PCDD/PCDF ambient air levels and depositions have been monitored in Hessen since 1989. Data were already presented and discussed by LIEBL et al. (14). Altogether a considerable reduction in dioxin immissions and depositions occured during the last 4 years, mainly due to identification of sources and measures to reduce emissions. Data on dioxins in breast milk in Northrhine Westphalia (based on investigations by FORST et al., from Ref. 13) and Lower Saxony (based on investigations by ENDE et al., from Ref. 13) also seem to indicate a trend towards lower values. In 1992 Northrhine Westphalia published a report based on 526 datasets (20). In international TEQ a decrease from ca. 34 pg TEQ/g fat in 1989 to 23 pg TEQ/g fat in 1991 was observed (Fig. 3).

2451

! i~'

~.~3" i. i

~3~'"

:~.

~" --.~;

': ." .-~,~.-'~=

1987

•, ~ .~.

.

.

.

~

-. ;. •

~..-.

m"

~ 2 - " " " "~.-"~

1988

.......... .~

~ ~.~=~

N=+ ,, ~.:"~

1989

,. . . . . . . . . . . . . . . . . . . . . . . . . .:.-~. :

~:

°.

.

.

"...

~. ~

N ":, -"

~:

:e...

.. ~ :

"~.~. -. " ~ :

|+

"..'..~.: •

..: .';~!:"+.~÷33~9

1990 ::'re,i," :+:'p.::+'.=-:"~:'~ + . : ' ~ . ~ ; . p . ; ' }

1991

•

+ + - m -

:

.

:

-

t+:::':-.'='::::*:-.':~-..~...~.,<:':p~

-

•

m:'- :.~.:~.

"~

+ :

+ :++m.. ~:~

0

"~=' "::+-3

10

+~-=+:+++:~:+:::::+++:+:+:+:+:.,

+:"

..~m 23 .

20

30

pg I-TEQ/g fat

Fig. 3. PCDD/PCDF (I-TEQ) in breast milk in Northrhine Westfalia. For single congeners data f r o m L o w e r Saxony s h o w a decrease especially for the higher chlorinated dioxins (Fig.4; from Ref. 13).

Due to t h e small n u m b e r of samples available and the short period during w h i c h t h e y have been collected the trend of c o n t a m i n a t i o n cannot yet be soundly assessed on this basis. A decrease has been indicated but has still to be confirmed w i t h i n the n e x t years. The Federal Minister for the Environment, Nature Conservation and Nuclear Safety has d e t e r m i n e d to introduce the necessary environmental p r o t e c t i o n m e a s u r e s in order to i m p r o v e preventive health protection and to finally reach a daily h u m a n intake of PCDD/PCDF of less than 1 pg TEQ/kg body w e i g h t . Currently one of the main p r o b l e m s is the PCP issue. PCP w a s banned in Germany by ordinance in 1989. This ordinance (Ordinance on the Ban on Pentachlorophenol - PCP-Verbotsv e r o r d n u n g ) w a s notified by the EEC-Commission based on article lOOa EEC-Treaty, which

a l l o w s single state regulations for i m p o r t a n t needs of e.g. e n v i r o n m e n t a l

p r o t e c t i o n . The decision of the EEC-Commission to notify the German Ordinance on the

Ban

of

PCP

is

currently

being

sued

by

France

at

the

European

2452 Supreme Court in Luxemburg. According to the French position the German ban on PCP contradicts economic liberalisation within the EEC (article 3o - 34 EEC-Treaty) and is an arbitrary discrimination and hidden impediment to free trade (article 36

O"J

i• 1I

1~

OCO0" l n

1tll

1Ill

1I

I

|

year Fig. 4. Dioxin congeners in breast milk in Lower Saxony (pg TEQ/g fat). EEC-Treaty). Germany holds the position based on article 100a EEC-Treaty according to which single state regulations are possible if they are justified by needs of

occupationat health or environmental protection. Analyses of PCP and PCP products as well as balance sheet calculations by HAGENMAIER (4) in 1990 have shown that PCP still is a major source for dioxin release into the environment. Thus, if the ban on PCP has to be abrogated the measures described here to minimize further dioxin release into the environment (which cost a lot of money) would suffer a severe drawback.

2453

REFERENCES 1 Schulz D. PCDD/PCDF - German policy and measures to protect man and the environment. Chemosphere, Vol. 27, Nos. 1-3, pp 501-507, 1993. 2 The Toxicology Forum. Health Effects and Safety Assessment of Dioxins and Furans. Washington D.C., 1990. 3 UBA (FEA). Dioxinsymposium Karlsruhe Januar 1990. Volume 1: Sachstandsbericht; Texte 49/91. Published by the Federal Environmental Agency, Berlin 1991. 4 UBA (FEA). Dixonsymposium Karlsruhe Januar 1990. Volume 2: Wortprotokoll der AnhSrung; Texte 50/91. Published by the Federal Environmental Agency, Berlin, 1991. 5 UBA (FEA). Dioxin symposium Karlsruhe, January 1990: situation report. FEATEXTS 9/93. Published by the Federal Environmental Agency, Berlin 1993. 6 BUA (Beratergremium fSr umweltrelevante Altstoffe). Chloranil. BUA-Stoffbericht 85, Februar 1992. Weinheim. 7 Hutzinger O and A Heindl. Systematische Untersuchung von Prozessen der organischen Chlorchemie auf die Bildung dioxinhaltiger RL~ckstiinde (systematic investigation of processes of organic chlorine chemistry for the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans). UFOPLAN Vorhaben 87103 03 518. 8 Hutzinger O, J. Towara, R.Fuchs and B.Hiller. Vermeidung di0xinhaltiger ROckst~nde bei der industriellen Herstellung und Anwendung chlororganischer Produkte (avoidance of dioxin-containing residues in industrial production and application of chloroorganic products). BMFT-Vorhaben 14 505 308. 9 BMU. Bericht der Bund/L~nder-Arbeitsgruppe DIOXINE - Rechtsnormen, Richtwerte, Handlungsempfehlungen, Mel~programme, Mel~werte und Forschungsprogramme. Published by the Federal Ministry for Environment, Nature Conservation and Nuclear Safety, Bonn 1992. 10 UBA. Dioxinbelastung der Umwelt in der Bundesrepublik Deutschland - Mel~programme, Mel~werte, Mel~methoden. Abschlul~bericht der UAG I "Mel'&programme" der Bund/L~nder-Arbeitsgruppe "Dioxine". Texte 21/92. Published by the Federal Environmental Agency, Berlin, 1992. 11 BMU. Zweiter Bericht der Bund/L~nder-Arbeitsgruppe DIOXlNE. Published by the Federal Minister for Environment, Nature Conservation and Nuclear Safety, Bonn 1993. 12 The Toxicology Forum. Current Views on the Impact of Dioxins and Furans on Human Health and the Environment. Washington D.C.1993., 13 UBA (FEA). Dioxin - Symposium "Current Views of Dioxins and Furans on Human Health and the Environment." TEXTE 30/93. Published by the Federal Environmental Agency, Berlin 1993. 14 LiebI,K., M. BL~chen, W. Ott and W. Fricke. Polychlorinated dibenzo(p)dioxins and dibenzofurans in ambient air; concentration and deposition measurements in Hessen, Germany. Organohalogen Compounds 12:85 (1993).

2454

15 BGA (FHO). 2. Anh6rung des Bundesgesundheitsamtes und Umweltbundesamtes zur gesundheitlichen Beurteilung von Dioxinen und Furanen. MvP Hefte 3/1993. 16 Dioxine und Furane - ihr Einflul~ auf Umwelt und Gesundheit. Bundesgesundheitsblatt, 36. Jahrgang,Sonderheft Mai 1993. 17 UBA (FEA).Dioxin Symposium Berlin November 1992, preliminary evaluation: Current Views on the Impact of Dioxins and Furans on Human Health and the Environment. TEXTE 27/93. Published by the Federal Environmental Agency, Berlin 1993. 18 Erarbeitung yon Anforderungen zur Emissionsbegrenzung von Dioxinen und Furahen (elaborating demands to reduce dioxin emissions). Bericht der Arbeitsgruppe des Unterausschusses Luft/Technik des L~nderausschusses for Immissionsschutz; April 1993. To be published. 19 RSckgang von chlororganischen Verbindungen im Rhein (Decrease of chlororganic compounds in the Rhine River). BMU-Umwelt 1/1993, p.30. 20 Ministerium f~ir Umwelt, Raumordnung und Landwirtschaft des Landes NordrheinWestfalen. Ergebnisse der landesweiten Untersuchung von Frauenmilch auf Dioxine und Furane zeigen Reckgang (Results of the state wide investigation of breast milk on dioxins and furans shows decrease). Press release, 1992. 21 Erste Verordnung zur ~.nderung der Chemikalienverbotsverordnung. To be published in Bundesgesetzblatt (BGBI.), July 1994.