Risk Assessment at Hazardous Waste Sites - American Chemical

7 Monitoring to Support Risk Assessments at Hazardous Waste Sites

Downloaded by UNIV OF ROCHESTER on January 19, 2018 | http://pubs.acs.org Publication Date: October 20, 1982 | doi: 10.1021/bk-1982-0204.ch007

GLENN E. SCHWEITZER U.S. Environmental Protection Agency, Environmental Monitoring Systems Laboratory, Las Vegas, NV 89114 The classical approaches to m u l t i m e d i a monitoring a t h a z a r d o u s w a s t e sites a r e briefly reviewed, with examples from r e c e n t site investigations. The types of monitoring d a t a t h a t a r e most useful i n risk a s s e s s m e n t s a r e d i s c u s s e d in t e r m s o f feasibility, costs, and t i m e for acquisition. Required emphases f o r assessing e n v i r o n m e n t a l h o t s p o t s and for d e t e r m i n i n g long-term habitability of a larger area are described. Special attention is directed to g e o p h y s i c a l t e c h n i q u e s , biological monitoring, and t h e triple s t a g e q u a d r u p o l e mass s p e c t r o m e t e r .

I n r e c e n t y e a r s e n v i r o n m e n t a l m o n i t o r i n g a c t i v i t i e s have been u n d e r t a k e n a t h u n d r e d s o f h a z a r d o u s w a s t e s i t e s t h r o u g h o u t t h e c o u n t r y . W h i l e some o f t h e s e e f f o r t s d a t e back a decade o r more, most o f t h e m o n i t o r i n g h a s been i n i t i a t e d d u r i n g t h e p a s t s e v e r a l years i n a n t i c i p a t i o n of o r i n response t o Governmental r e g u l a t o r y a c t i o n s a t t h e n a t i o n a l , s t a t e , and l o c a l l e v e l s . O f t e n t h e m o n i t o r i n g h a s b e e n t a r g e t e d o n one, two, o r a s m a l l number o f c h e m i c a l s . I n o t h e r c a s e s t h e 129 p r i o r i t y p o l l u t a n t s have been t h e s u b j e c t o f i n v e s t i g a t i o n s . I n a few c a s e s a v a r i e t y o f a n a l y t i c a l methods have been u s e d i n e f f o r t s t o i d e n t i f y and measure s t i l l l a r g e r numbers o f p o s s i b l e e n v i r o n mental containments. As i n d i c a t e d i n F i g u r e 1, a l l e n v i r o n m e n t a l m e d i a where p o l l u t a n t s c o u l d l o d g e h a v e been o f i n t e r e s t , i n c l u d i n g a i r , s u r f a c e w a t e r a n d s e d i m e n t , s o i l , a n d g r o u n d w a t e r . The e n v i r o n m e n t a l pathways o f g r e a t e s t c o n c e r n o b v i o u s l y v a r y f r o m s i t e t o site. F i g u r e 2 summarizes t h e media o f p r i n c i p a l i n t e r e s t a t n i n e " t y p i c a l " s i t e s s e l e c t e d f r o m a n EPA s u r v e y o f 160 s i t e s . I n a d d i t i o n , man-made p a t h w a y s f o r p o l l u t a n t s h a v e t a k e n o n new s i g n i f i c a n c e — sewage a n d d r i n k i n g w a t e r s y s t e m s , i r r i g a t i o n a n d d r a i n a g e systems, and c u t and f i l l a c t i v i t i e s . E v e n measurements

0097-6156/82/0204-0073$06.00/0 © 1982 American Chemical Society

Long and Schweitzer; Risk Assessment at Hazardous Waste Sites ACS Symposium Series; American Chemical Society: Washington, DC, 1982.


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Direct Human Exposure: Via Dermal Contact & Inhalation

Gaseous & Airborne Particles

Figure 1.

Exposure pathways.

Indirect Human Exposure: Deposition on Crops & Ingestion-Bioaccumulation in Grazing Animals

Human Exposure: Recreation Contact & Water Supply

Deposition

Recharge to Stream



Figure 2. Case studies of typical inactive sites. (Reproduced from Réf. 1.)


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of i n d o o r a i r q u a l i t y and basement sump c o n t a m i n a t i o n have been l i n k e d t o waste s i t e problems. Remote m o n i t o r i n g t e c h n i q u e s have been u s e d t o complement conventional environmental monitoring a c t i v i t i e s . The u s e o f c u r r e n t and a r c h i v a l a e r i a l p h o t o g r a p h y and m u l t i s p e c t r a l o v e r head i m a g e r y t o u n c o v e r and d e l i n e a t e w a s t e s i t e p r o b l e m s h a s e x p a n d e d c o n s i d e r a b l y . A l s o , g r o u n d p e n e t r a t i n g remote s e n s i n g t e c h n o l o g i e s a r e being used t o d e l i n e a t e the s u b s u r f a c e d i s t r i b u t i o n o f w a s t e m a t e r i a l s and t o h e l p t a r g e t m o n i t o r i n g a c t i v i ties. I n a d d i t i o n , t h e s e g e o p h y s i c a l t e c h n o l o g i e s have been shown t o o f f e r p r o m i s e f o r d e t e c t i n g u n d e r g r o u n d movement o f p o l l u t i o n plumes. B i o l o g i c a l m o n i t o r i n g h a s o c c a s i o n a l l y been c o n d u c t e d a t hazardous waste s i t e s t o c l a r i f y p o s s i b l e food c h a i n problems. Food c r o p s , l i v e s t o c k , and l o c a l f i s h i n p a r t i c u l a r have been o f concern. I n a d d i t i o n , w i l d a n i m a l s and i n d i g e n o u s v e g e t a t i o n have been s a m p l e d t o f i n d i n d i c a t i o n s o f l o c a l c o n t a m i n a t i o n problems. I n s h o r t , t h e l a r g e number of m u l t i - c h e m i c a l , m u l t i - m e d i a e n v i r o n m e n t a l measurements a s s o c i a t e d w i t h h a z a r d o u s w a s t e i n v e s t i g a t i o n s d u r i n g t h e p a s t few y e a r s a r e u n p r e c e d e n t e d i n s c o p e and c o m p l e x i t y . The s m a l l community o f s p e c i a l i s t s i n t h e measurements f i e l d i s b e i n g pushed t o t h e l i m i t t o r e d u c e t h e t i m e and c o s t i n v o l v e d i n s u c h measurements and t o i m p r o v e t h e r e p r e s e n t a t i v e n e s s o f t h e d a t a t h a t a r e c o l l e c t e d and t h e a c c u r a c y of t h e d a t a t h a t a r e r e p o r t e d . R e l a t i n g M o n i t o r i n g Data t o R i s k s M o n i t o r i n g a c t i v i t i e s h a v e u s u a l l y been c a r r i e d o u t t o h e l p c l a r i f y the r i s k s , i f any, a s s o c i a t e d w i t h s p e c i f i c s i t e s . While e v e r y d a t a p o i n t t h a t c o u l d be o b t a i n e d may be o f some i n t e r e s t , the c h a l l e n g e i s t o maximize t h e u s e f u l n e s s f o r r i s k assessment of m o n i t o r i n g d a t a t h a t a r e c o l l e c t e d and a n a l y z e d w i t h i n c o s t and t i m e c o n s t r a i n t s . U n f o r t u n a t e l y , h e a l t h assessment s p e c i a l i s t s h a v e p r o v i d e d l i t t l e g u i d a n c e t o d a t e as t o t h e t y p e o f m o n i t o r i n g i n f o r m a t i o n t h a t w o u l d be most u s e f u l t o them i n determining r i s k s to i n d i v i d u a l s or to larger populations. One a p p r o a c h t o r e l a t i n g m o n i t o r i n g a t a h a z a r d o u s w a s t e s i t e t o r i s k assessment i s s i m p l y t o determine whether e x i s t i n g a i r o r water q u a l i t y standards a r e b e i n g exceeded i n the v i c i n i t y of t h e s i t e a n d w h e t h e r s u c h e x c e s s e s a r e due t o t h e p r e s e n c e o f the s i t e . W i t h r e g a r d t o g r o u n d w a t e r , Maximum C o n t a m i n a n t L e v e l s (MCLs) e s t a b l i s h e d f o r d r i n k i n g w a t e r h a v e been s u g g e s t e d a s surrogate standards. A p r i n c i p a l drawback i n t h i s approach i s t h a t s t a n d a r d s a n d MCLs e x i s t f o r o n l y a f e w c h e m i c a l s . Another o b v i o u s d e f i c i e n c y i s t h a t when a s t a n d a r d h a s been e x c e e d e d , i t may be t o o l a t e f o r e f f e c t i v e r e m e d i a l a c t i o n . A s e c o n d t y p e o f a p p r o a c h i s t o compare c o n t a m i n a t i o n l e v e l s i n t h e media o f i n t e r e s t n e a r t h e s i t e w i t h p o l l u t i o n l e v e l s i n



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Monitoring to Support Assessments

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t h e same m e d i a i n c o n t r o l a r e a s . Of s p e c i a l i n t e r e s t w o u l d be a c o n t r o l a r e a n e a r t h e w a s t e s i t e — b u t i n s u l a t e d by g e o g r a p h i c f e a t u r e s from the d i r e c t i n f l u e n c e of the s i t e . T h i s area would be i m p a c t e d b y a l l o f t h e i n d u s t r i a l e m i s s i o n s and e f f l u e n t s t h a t p e r m e a t e t h e r e g i o n as w e l l as o t h e r common s o u r c e s o f c o n t a m i n a t i o n such as a g r i c u l t u r a l c h e m i c a l s . Thus, i n comparing t h e contamination near the s i t e w i t h the contamination i n the c o n t r o l a r e a , i t s h o u l d be p o s s i b l e t o a t t r i b u t e a n y h i g h e r l e v e l s o f contaminants found near t h e s i t e t o the i n f l u e n c e of the s i t e i t s e l f and n o t t o t h e b a c k g r o u n d c h a r a c t e r i s t i c s o f t h e r e g i o n . A s e c o n d t y p e o f c o n t r o l c o u l d be p r o v i d e d by n a t i o n a l b a s e l i n e data. Such d a t a i n d i c a t i n g t h e l e v e l s o f a m b i e n t o r b a c k g r o u n d c o n t a m i n a t i o n u s u a l l y e n c o u n t e r e d i n d i f f e r e n t t y p e s o f demographic s e t t i n g s could help c l a r i f y the s i g n i f i c a n c e of e n v i r o n m e n t a l measurements n e a r a h a z a r d o u s w a s t e s i t e . The c l a s s i c a l a p p r o a c h o f e s t i m a t i n g m u l t i m e d i a e x p o s u r e s t o i n d i v i d u a l c h e m i c a l s and t h e n e s t i m a t i n g t h e r e l a t e d r i s k s t o s e n s i t i v e p o p u l a t i o n s through a combination of modeling, m o n i t o r i n g , a n d t o x i c o l o g i c a l e v a l u a t i o n does n o t a p p e a r v e r y p r o m i s i n g . U s u a l l y t h e r e a r e t o o many c h e m i c a l s and c h e m i c a l m i x t u r e s i n v o l v e d , t o o many u n c e r t a i n t i e s i n e s t i m a t i n g c h e m i c a l f a t e and t r a n s p o r t and h e n c e t h e r i s k s t o f u t u r e g e n e r a t i o n s , and t o o many unknown c o n c e r n i n g f u t u r e s i t e c o n t a m i n a n t f a i l u r e s t o g i v e much credence t o such approaches. S t i l l , i n cases i n v o l v i n g h i g h l y t o x i c c h e m i c a l s such as d i o x i n c o n t a m i n a t i o n , d e t a i l e d a n a l y s i s of t h e p r e s e n c e a n d l i k e l y e n v i r o n m e n t a l b e h a v i o r o f s u c h i n d i v i d u a l c h e m i c a l s may be i m p o r t a n t , and m o n i t o r i n g c a p a b i l i t i e s t o d e t e c t and measure t h e p r e s e n c e o f s u c h c h e m i c a l s a t l o w c o n c e n t r a t i o n s w i l l be c r i t i c a l . F i n a l l y , s e v e r a l r a n k i n g s y s t e m s h a v e been d e v e l o p e d f o r p r i o r i t i z i n g t h e r e l a t i v e h a z a r d s a t a l a r g e number o f s i t e s . T h i s a p p r o a c h u s u a l l y i n v o l v e s a w e i g h t i n g of t h e amount a n d c o m p o s i t i o n of hazardous m a t e r i a l a t each s i t e , the contaminant c h a r a c t e r i s t i c s of t h e s i t e , t h e p o t e n t i a l m i g r a t i o n p a t h w a y s , and t h e p r o x i m i t y o f e n v i r o n m e n t a l o r human p o p u l a t i o n s . Variat i o n s o f t h i s a p p r o a c h h a v e a l r e a d y been a p p l i e d many t i m e s , e i t h e r i n a q u a s i - r i g o r o u s f a s h i o n o r i n a more g e n e r a l manner, as s t a t e and l o c a l a u t h o r i t i e s a r e f a c e d w i t h d e c i d i n g where t o concentrate l i m i t e d resources. The

G e n e r a l A p p r o a c h t o S a m p l i n g and A n a l y s i s

Monitoring a c t i v i t i e s involve several interrelated steps: — D e c i d i n g where and how t o t a k e r e p r e s e n t a t i v e s a m p l e s o f t h e m e d i a o f i n t e r e s t and how t o h a n d l e t h e s a m p l e s en r o u t e t o the a n a l y t i c a l l a b o r a t o r i e s . — S e l e c t i n g a n a l y t i c a l methods t o i n v e s t i g a t e t h e p r e s e n c e o r a b s e n c e o f e i t h e r a f i n i t e o r open ended l i s t o f c h e m i c a l s .



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— C h o o s i n g a p r o c e d u r e and f o r m a t f o r a g g r e g a t i n g and p r e s e n t i n g t h e r e s u l t s of t h e a n a l y s i s and f o r s e t t i n g f o r t h t h e d e g r e e of c o n f i d e n c e i n t h e d a t a . — D e t e r m i n i n g how t o i n t e r p r e t t h e m o n i t o r i n g d a t a as t o p r e s e n c e , q u a n t i t y , t r a n s f o r m a t i o n , and m i g r a t i o n o f t h e c h e m i c a l s of i n t e r e s t . We a r e r a p i d l y a c q u i r i n g e x p e r i e n c e i n a l l of t h e s e a r e a s . Over t h e y e a r s many manuals h a v e been p r e p a r e d by a number o f g r o u p s on s a m p l i n g and a n a l y t i c a l methods. S a m p l i n g d e s i g n i s u s u a l l y s i t e - s p e c i f i c , and s o m e t i m e s c h e m i c a l - s p e c i f i c , and c a s e s t u d i e s o f d i f f e r e n t a p p r o a c h e s t h a t have been u s e d i n t h e p a s t are p a r t i c u l a r l y i n s t r u c t i v e i n p r o v i d i n g f u t u r e guidance i n t h i s a r e a . However, w i t h r e g a r d t o t h e p r e s e n t a t i o n and i n t e r p r e t a t i o n of d a t a , we h a v e o n l y begun t o d e v e l o p u s e f u l a p p r o a c h e s f o r r e l a t i n g m o n i t o r i n g d a t a t o r i s k s — t h e t h r u s t of t h i s symposium. A few of t h e l e s s o n s we have l e a r n e d t o d a t e i n c a r r y i n g o u t m o n i t o r i n g programs a r e as f o l l o w s : 1. A t t h e o u t s e t t h e o b j e c t i v e s of t h e m o n i t o r i n g p r o g r a m s h o u l d be c l e a r l y d e f i n e d . M o n i t o r i n g programs can be h e l p f u l b o t h i n i d e n t i f y i n g h o t s p o t s o f n e a r t e r m c o n c e r n and i n a s s e s s i n g t h e l o n g e r t e r m h a b i t a b i l i t y o f t h e a r e a . E a c h of t h e s e o b j e c t i v e s may r e q u i r e a d i f f e r e n t p r o g r a m o r i e n t a t i o n , h o w e v e r , as shown i n F i g u r e 3. U s u a l l y b o t h o b j e c t i v e s w i l l be i m p o r t a n t i n v a r y i n g d e g r e e s , and t h e p r o g r a m e m p h a s i s s h o u l d be a d j u s t e d accordingly. P r i o r to i n i t i a t i n g the m o n i t o r i n g program, the u s e r s of t h e m o n i t o r i n g d a t a s h o u l d be s a t i s f i e d t h a t t h e d a t a w i l l be c o l l e c t e d , a n a l y z e d , and p r e s e n t e d i n a manner w h i c h i s r e s p o n s i v e to t h e i r needs. 2. S e v e r a l f a c t o r s are important i n s e l e c t i n g the i n d i v i d u a l c h e m i c a l s of s p e c i a l i n t e r e s t . For example, c e r t a i n c h e m i c a l s may have been d e p o s i t e d a t t h e s i t e i n v e r y l a r g e q u a n t i t i e s , and t h e r e f o r e t h e y a r e of p r i n c i p a l c o n c e r n s i m p l y b e c a u s e o f t h e i r v o l u m e . S e c o n d l y , one o r more of t h e c h e m i c a l s known t o be p r e s e n t a t t h e s i t e may be so t o x i c t h a t t h e p o t e n t i a l t h r e a t e v e n a t low v o l u m e s i s o b v i o u s l y a m a j o r c o n c e r n (e.g., d i o x i n ) . C e r t a i n " i n d i c a t o r " c h e m i c a l s commonly f o u n d a t w a s t e s i t e s may behave i n t h e e n v i r o n m e n t i n a manner c h a r a c t e r i s t i c of many o t h e r c h e m i c a l s as w e l l ( e . g . g r o u p s o f p e s t i c i d e s ) , and d e t e r m i n i n g t h e e n v i r o n m e n t a l d i s t r i b u t i o n of s u c h " i n d i c a t o r " c h e m i c a l s c o u l d be i n d i c a t i v e o f b r o a d e r c o n t a m i n a t i o n p r o b l e m s . A n a l y s i s of l e a c h a t e f r o m t h e edge o f t h e s i t e o r p r e l i m i n a r y m o n i t o r i n g c l o s e t o the s i t e might i d e n t i f y c h e m i c a l s t h a t are e s c a p i n g from the s i t e . F i n a l l y , sampling f o r a group of c h e m i c a l s w h i c h a r e u s u a l l y a n a l y z e d as a p a c k a g e s u c h as t h e 129 p r i o r i t y p o l l u t a n t s m i g h t r e s u l t i n c o n s i d e r a b l e s a v i n g s p e r c h e m i c a l i n a n a l y t i c a l c o s t s . A l l of t h e s e f a c t o r s s h o u l d h a v e a b e a r i n g on t h e s e l e c t i o n of t h e c h e m i c a l s f o r i n t e n s i v e i n v e s tigation. 3. S t a t i s t i c a l a s p e c t s a r e an i m p o r t a n t f a c t o r i n t h e d e s i g n of a m o n i t o r i n g p r o g r a m t h a t i s t o p r o v i d e r e p r e s e n t a t i v e


Long and Schweitzer; Risk Assessment at Hazardous Waste Sites ACS Symposium Series; American Chemical Society: Washington, DC, 1982. Many chemicals including degradation products All levels including trace levels Past, current, and future leakages Also, soil, sediment, biota, surface water, sewers, groundwater Entire population Document highest and median concentration levels in individual media and compare such levels with control areas General multimedia sampling of broad areas with bias toward natural and man-made pathways from the site. Concurrent monitoring in nearby control areas. Monitor along entire environmental pathway.

High toxicity chemicals suspected to be in area "High" levels Past and current leakages at site Air, drinking water, food Susceptible individuals near hot spots Determine highest intergrated exposure levels for specific groups of individuals Limited multimedia sampling of broad areas and intensive single media monitoring of suspected hot spots near populations. Emphasize monitoring at interface of receptor.

Chemicals of concern

Levels of concern

Likely sources

Pathways of primary concern

Populations of concern

Assessment emphasis

Monitoring approach

Assessing exposures near uncontrolled sites.

Determine long term habitability of area

Identify near term exposure problems

Objective

Figure 3.

Assessing Chemical Saturation

Assessing Hot Spots



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data. A s t a t i s t i c i a n on t h e p l a n n i n g team c a n h e l p i n s u r e t h a t adequate c o n s i d e r a t i o n i s g i v e n t o these aspects both i n d e s i g n i n g t h e p r o g r a m and i n f o r m a t t i n g and i n t e r p r e t i n g d a t a . A photo i n t e r p r e t e r c a n a l s o be a n i m p o r t a n t member o f t h e p l a n n i n g team, b o t h i n s e l e c t i n g m o n i t o r i n g s i t e s and i n d e s i g n i n g t h e a p p r o a c h for relating concentration levels to population a c t i v i t i e s . 4. B e f o r e any s a m p l e s a r e t a k e n , a c o m p l e t e s a m p l i n g p l a n s h o u l d be d e v e l o p e d w i t h b u i l t - i n c h e c k p o i n t s f o r a d j u s t i n g t h e p l a n as sampling r e s u l t s a r e o b t a i n e d . D e v i a t i o n s from the p l a n s h o u l d be r e s i s t e d o t h e r t h a n t o a d j u s t t h e p l a n i n r e s p o n s e t o unexpected data r e s u l t s . As a r u l e o f thumb, on t h e o r d e r o f f i f t e e n p e r c e n t o f t h e s a m p l i n g m i g h t be f o r s c r e e n i n g t o h e l p c l a r i f y h y p o t h e s e s a s t o p o s s i b l e g r a d i e n t s and h o t s p o t s a r o u n d the s i t e s , s e v e n t y p e r c e n t d i r e c t e d t o i n v e s t i g a t i n g t h e h y p o t h e s e s , and f i f t e e n p e r c e n t r e s e r v e d f o r s u p p l e m e n t a r y s a m p l i n g o f n e g l e c t e d a r e a s t h a t come t o l i g h t l a t e i n t h e p r o g r a m . The s a m p l i n g scheme s h o u l d i n c l u d e p r o v i s i o n s t o confirm o r r e j e c t p r e v i o u s l y reported f i n d i n g s of a c o n t r o v e r s i a l nature. Access t o p r e f e r r e d sampling s i t e s i s not always possible. The s a m p l i n g p l a n s h o u l d be s u f f i c i e n t l y f l e x i b l e t o compensate f o r s u c h p r o b l e m s . 5. A q u a l i t y a s s u r a n c e program i n v o l v i n g s u r r o g a t e r e c o v e r i e s , i n t e r and i n t r a l a b o r a t o r y d u p l i c a t e s , and f i e l d and laboratory blanks i s e s s e n t i a l . E a c h d a t a p o i n t s h o u l d be i n d i v i d u a l l y v a l i d a t e d a s a c c e p t a b l e d a t a , and p r e c i s i o n and a c c u r a c y d a t a s h o u l d be d e v e l o p e d f o r e a c h d a t a s e t . The q u a l i t y a s s u r a n c e p r o g r a m may a c c o u n t f o r 10 t o 20 p e r c e n t o f t h e m o n i t o r i n g c o s t s . S p e c i a l e f f o r t s a r e needed t o m i n i m i z e h o l d i n g t i m e s between s a m p l i n g and a n a l y s i s . However, e x t e n d e d h o l d i n g t i m e s beyond t h e u s u a l t a r g e t o f two weeks may be u n a v o i d a b l e . I n t h a t event a p p r o p r i a t e storage procedures a r e p a r t i c u l a r l y important t o prevent e x c e s s i v e decay o f t h e samples. A l s o , c o n t a m i n a n t s a s s o c i a t e d w i t h t h e s a m p l i n g and a n a l y t i c a l t e c h n i q u e s a r e o f t e n d i f f i c u l t t o a v o i d , and d a t a s u s p e c t e d o f s u c h c o n t a m i n a t i o n s h o u l d be c o n s i d e r d f o r d i s c a r d i n g . Of p a r t i c u l a r c o n c e r n , f o r e x a m p l e , a r e benzene and t o l u e n e c o n t a m i n a t i o n when u s i n g T e n a x t r a p s , m e t h y l e n e c h l o r i d e and phthalates that a r e present i n l a b o r a t o r i e s , isophorone which can be a d e r i v a t i v e o f t h e l a b o r a t o r y s o l v e n t a c e t o n e , and t h e h i g h pH i n g r o u n d w a t e r a s s o c i a t e d w i t h g r o u t i n g o f s a m p l i n g w e l l s w h i c h may r e s u l t i n a r t i f a c t s b e i n g o b s e r v e d . 6. D a t a f o r m a t t i n g and p r e s e n t a t i o n c a n h a v e a s i g n i f i c a n t i m p a c t on t h e i n t e r p r e t a t i o n o f t h e d a t a . P l o t t i n g each data p o i n t on a map i s p r o b a b l y t h e s a f e s t way t o i n s u r e a t o t a l l y o b j e c t i v e p r e s e n t a t i o n o f f i n d i n g s . M o n i t o r i n g d a t a may n o t provide a d e f i n i t e p o r t r a y a l of p o l l u t a n t gradients or p o l l u t i o n p a t t e r n s b u t may o n l y be s u g g e s t i v e o f g e n e r a l p o l l u t a n t distribution. I n t e r p r e t a t i o n s o f t h e d a t a may be c o n t r o v e r s i a l , and e f f o r t s s h o u l d be made t o i s o l a t e c r i t i c i s m s o f t h e i n t e r p r e tations.


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These and o t h e r l e s s o n s l e a r n e d s e t an i m p o r t a n t f r a m e w o r k f o r our r e s e a r c h e f f o r t s t o improve m o n i t o r i n g c a p a b i l i t i e s . D i s c u s s e d b e l o w a r e t h r e e a r e a s of c u r r e n t r e s e a r c h i n t e r e s t .


Geophysical

Techniques

The i n c r e a s i n g i m p o r t a n c e of g e o p h y s i c a l i n v e s t i g a t i o n s has been r e p e a t e d l y documented i n r e c e n t months. The most commonly u s e d t e c h n i q u e s have been s e i s m i c r e f r a c t i o n , g r o u n d p e n e t r a t i n g r a d a r , e l e c t r i c a l c o n d u c t i v i t y , and magnetometer s u r v e y s . Figure 4 p r e s e n t s a c o m p a r i s o n of an a n a l y s i s of d a t a f r o m 16 g r o u n d w a t e r s a m p l i n g w e l l s w i t h an a n a l y s i s of e l e c t r o m a g n e t i c d a t a i n d e t e r m i n i n g plume f l o w . F i g u r e 5 u n d e r s c o r e s how c o n d u c t i v i t y d a t a m i g h t h a v e been u s e d t o i m p r o v e t h e l o c a t i o n of s a m p l i n g wells. F i n a l l y , F i g u r e 6 r e f l e c t s t h e p o t e n t i a l c o n t r i b u t i o n s of geophysical i n v e s t i g a t i o n s to help plan remedial a c t i o n s . E f f o r t s have a l s o been i n i t i a t e d t o i n s t r u m e n t new s i t e s w i t h e l e c t r o d e systems f o r d e t e c t i n g l e a c h a t e leakage through the l i n e r s of t h e s i t e s . One a p p r o a c h i s t o s u r r o u n d t h e s i t e w i t h r e s i s t i v i t y s o u n d i n g s t a t i o n s u s i n g t h e e a r t h as t h e c o n d u c t i n g medium. A n o t h e r a p p r o a c h has been t o embed a w i r e g r i d j u s t below the s i t e . I n e i t h e r c a s e , changes i n r e s i s t i v i t y m e a s u r e ments w o u l d s i g n a l a p o s s i b l e l e a c h a t e plume m i g r a t i n g downward from the s i t e . W h i l e t h i s t e c h n i q u e seems v e r y a p p e a l i n g , c o n s i d e r a b l e proof t e s t i n g i s i n order g i v e n the n e c e s s i t y f o r s y s tems t h a t w i l l m i n i m i z e f a l s e a l a r m s and w i l l o p e r a t e r e l i a b l y f o r many d e c a d e s . Another promising approach c a l l s f o r combining l a s e r - i n d u c e d f l u o r e s c e n c e t o i n d i c a t e p o l l u t a n t c o n t a m i n a t i o n of an aqueous body, and i n t h i s c a s e g r o u n d w a t e r , w i t h f i b e r o p t i c t e c h n i q u e s f o r e n t e r i n g the e a r t h through v e r y s m a l l diameter w e l l s ( l e s s t h a n one i n c h ) . This approach i s p a r t i c u l a r l y a t t r a c t i v e i n a t t e m p t i n g t o measure T o t a l O r g a n i c C a r b o n (TOC) a s a s u r r o g a t e f o r t h e p o l l u t i o n plume. I n d e e d , a p r i n c i p a l r e s e a r c h d i r e c t i o n i s d e m o n s t r a t i n g t h e f e a s i b i l i t y of TOC measurements w h i l e s e a r c h i n g f o r a d d i t i o n a l p o l l u t i o n s i g n a t u r e s t h a t c o u l d be d e t e c t e d by l a s e r f l u o r e s c e n c e . I f t h e method p r o v e s o p e r a t i o n a l l y f e a s i b l e , reductions i n w e l l diameters should r e s u l t i n considerable cost savings. Improved A n a l y t i c a l Methods As more p o t e n t i a l l y h a r m f u l c h e m i c a l s a r e d i s c o v e r e d , c o n c e r n f o r t h e l o n g - t e r m i m p a c t of low c o n c e n t r a t i o n s of l a r g e numbers of h a z a r d o u s e l e m e n t s and compounds i n c r e a s e s . The need f o r i m p r o v e d methods f o r a n a l y z i n g e n v i r o n m e n t a l s a m p l e s t o i d e n t i f y and measure v e r y s m a l l amounts of a w i d e v a r i e t y of c h e m i c a l s becomes c r i t i c a l . A number of a d v a n c e d methods f o r a n a l y z i n g e n v i r o n m e n t a l s a m p l e s a r e u n d e r i n v e s t i g a t i o n by r e s e a r c h e r s i n many



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Values in Millimhos/Meter

Figure 4. Monitor well measurements and electromagnetic measurements at same site. Top: potentiometric contours showing plume flow. Bottom: conductivity contours showing plumeflow.(Reproduced from Ref. 2.)



SCHWEITZER


Figure 5. Conductivity data showing buried hazardous materials. Key: · , wells drilled before conductivity data were available. (Reproduced from Ref. 2.)

Alternative

Informational Needs

Removal of Buried Drums and Chemicals

Drum Condition, Number, and Contents Trench Location and Geometry

Encapsulation of Source

Drum Contents Imperviousness of Underlying Strata Level of Subsurface Contamination Trench Location and Geometry

Collection and Treatment of Leachate

Areal Extent of Contamination Type of Contamination Concentration of Contaminants Imperviousness of Underlying Strata Aquifier Characteristics

No Action

Drum Contents and Condition Level of Subsurface Contamination Type of Contamination

Figure 6.

Informational needs for implementation of abatement activities. (Reproduced from Réf. 1.)


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laboratories. Of p a r t i c u l a r r e l e v a n c e t o t h e p r o b l e m s of hazardous wastes are the a p p l i c a t i o n of fused s i l i c a c a p i l l a r y columns i n GC/MS s y s t e m s , F o u r i e r t r a n s f o r m i n f r a r e d s p e c t r o s c o p y , and n o n - e x t r a c t i v e m u l t i - e l e m e n t a l a n a l y s i s . P r e s e n t MS t e c h n i q u e s f o r a n a l y s i s of o r g a n i c compounds i n c o m p l e x s a m p l e s r e q u i r e s e p a r a t i o n of t h e sample components p r i o r t o MS a n a l y s i s . The s e p a r a t i o n i s u s u a l l y a c c o m p l i s h e d by e x t r a c t i n g the samples, s e p a r a t i n g the e x t r a c t s i n t o s e v e r a l f r a c t i o n s ( c l e a n u p ) , and a n a l y z i n g t h e f r a c t i o n s by GC/MS. These s t e p s , e s p e c i a l l y t h e s a m p l e p r e p a r a t i o n and c l e a n u p , a r e t i m e c o n s u m i n g and e x p e n s i v e . The use of tandem mass s p e c t r o m e t e r s can e l i m i n a t e t h e sample p r e p a r a t i o n s t e p s and p r o v i d e i m p r o v e d c a p a b i l i t i e s f o r MS analysis. One s y s t e m , t h e t r i p l e q u a d r u p o l e mass s p e c t r o m e t e r , u s e s a c o m b i n a t i o n of t h r e e q u a d r u p o l e s , o r mass a n a l y z e r s , t o i o n i z e , s e p a r a t e , and a n a l y z e sample components w i t h minimum s a m p l e p r e p a r a t i o n as shown i n F i g u r e s 7 and 8. The sample components a r e i o n i z e d and s e p a r a t e d a c c o r d i n g t o t h e i r massto-charge r a t i o i n the f i r s t quadrupole. This step corresponds t o t h e GC s t e p i n GC/MS. I n t h e s e c o n d q u a d r u p o l e t h e s e i o n s c o l l i d e w i t h an i n e r t gas and f r a g m e n t ( c h e m i c a l i o n i z a t i o n ) . In t h e t h i r d q u a d r u p o l e t h e f r a g m e n t s a r e i d e n t i f i e d (mass analyzer). T r i p l e q u a d r u p o l e mass s p e c t r o m e t r y can p r o v i d e r a p i d s c r e e n i n g of c o m p l e x m i x t u r e s f o r s p e c i f i c compounds and can be u s e d t o a n a l y z e f o r compounds t h a t c a n n o t r o u t i n e l y be a n a l y z e d by GC/MS. I n a d d i t i o n , s t r u c t u r a l i n f o r m a t i o n can be o b t a i n e d f o r c e r t a i n t y p e s of compounds s i n c e i n c o l l i s i o n - i n d u c e d d i s s o c i a t i o n s t h e f r a g m e n t s a r e l i k e l y t o show t h e s t r u c t u a l d i f f e r e n c e s of t h e p a r e n t compounds. Complex m i x t u r e s h a v e been a n a l y z e d by t h i s t e c h n i q u e by i n t r o d u c i n g t h e sample d i r e c t l y i n t o t h e h e a t e d s a m p l e p o r t of t h e i n s t r u m e n t w i t h l i t t l e o r no sample p r e t r e a t m e n t . T r i p l e q u a d r u p o l e mass s p e c t r o m e t r y p r o m i s e s t o be a u s e f u l , c o s t - e f f e c t i v e , and p r a c t i c a l advanced technique f o r e n v i r o n m e n t a l a n a l y s i s , p a r t i c u l a r l y when a p p l i e d t o h a z a r d o u s w a s t e p r o b l e m s . M o n i t o r i n g i n Animals

and

Plants

As i n d i c a t e d i n F i g u r e 9, many a p p r o a c h e s t o m o n i t o r i n g a n i m a l s p e c i e s at hazardous waste s i t e s have been suggested. A l s o , v e g e t a t i o n m o n i t o r i n g i s commonly p r o p o s e d . V e r y few o f t h e s u g g e s t e d a p p r o a c h e s , h o w e v e r , a r e beyond t h e e a r l y r e s e a r c h s t a g e t o t h e p o i n t where t h e y c o u l d be d e p l o y e d t o p r o v i d e r e l i a b l e data concerning f i e l d contamination. The t y p e s of b i o l o g i c a l methods t h a t need t o be c a r e f u l l y e v a l u a t e d a n d , i f a p p r o p r i a t e , s t a n d a r d i z e d f o r f i e l d use i n c l u d e (1) l a b o r a t o r y s c r e e n i n g t e s t s t o a s s e s s the r e l a t i v e h a z a r d of c h e m i c a l m i x t u r e s , ( 2 ) f i e l d s u r v e y methods t o d e t e c t changes i n b i o l o g i c a l p o p u l a t i o n s , and ( 3 ) m o n i t o r i n g t e c h n i q u e s t o d e t e c t




SCHWEITZER



Ionize All Components of Mixture

®

(Mi)

Ionizer Focusing Lenses

Figure 8.

Select a Molecular Ion of Interest, M |

Qi

Quadrupole Mass Filter 2

3

Separate the Fragment Ions A* . . . A* According to Mass

Quadrupole Mass Filter

Triple-stage quadrupole mass spectrometer schematic.

Decompose M | by Collision With Neutral Gas Molecules ( · ) , Transmit All Ions Formed (A|. A+,.. . . Ap) to Mass Filter, Q

Q

Collision Cell


Output to Graphic Display

Detector

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t h e p r e s e n c e of s p e c i f i c compounds i n b i o l o g i c a l m a t e r i a l s . The t h r e e a p p r o a c h e s h a v e s e v e r a l f e a t u r e s i n common. These m e t h o d s , when a p p l i e d w i t h i n a p p r o p r i a t e e x p e r i m e n t a l d e s i g n s , may i n d i c a t e -the s o u r c e of p o l l u t a n t s and p o t e n t i a l l y can i n d i c a t e p o l l u t a n t d i s t r i b u t i o n i n the a i r , water, s o i l , or sediment a t study l o c a t i o n s . E q u a l l y i m p o r t a n t , t h e y can i d e n t i f y t h e e x t e n t of p r o b l e m s , t h e y can p r o v i d e i n f o r m a t i o n u s e f u l f o r h a z a r d e v a l u a t i o n s , and t h e y can f r e q u e n t l y h e l p i d e n t i f y s p e c i f i c p o l l u t a n t s , o r c o m b i n a t i o n s of p o l l u t a n t s , t h a t a r e causing problems. S c r e e n i n g T e s t s . S c r e e n i n g t e s t s can be u s e d d u r i n g i n i t i a l i n v e s t i g a t i o n s a t w a s t e s i t e s t o p r o v i d e a r a p i d a s s e s s m e n t of p o t e n t i a l h a z a r d s t o ( 1 ) f i e l d and l a b o r a t o r y p e r s o n n e l i n v e s t i g a t i n g t h e s i t e , ( 2 ) p e r s o n s i n t h e i m m e d i a t e v i c i n i t y of t h e s i t e , and ( 3 ) t h e n e a r b y e n v i r o n m e n t . Exposures of the s c r e e n i n g s y s t e m s a r e c o n d u c t e d u n d e r c o n t r o l l e d c o n d i t i o n s , u s u a l l y by b r i n g i n g s a m p l e s i n t o t h e l a b o r a t o r y o r by p l a c i n g t e s t o r g a n i s m s a t the s i t e . E x a m p l e s of s c r e e n i n g t e s t s t o c l a r i f y r e l a t i v e p e r s o n n e l h a z a r d s m i g h t i n c l u d e t h e d e t e c t i o n o f mutagens i n body f l u i d s of l a b o r a t o r y a n i m a l s e x p o s e d t o w a s t e s i t e m a t e r i a l and v a r i o u s immunotoxicity responses i n l a b o r a t o r y animals. The d e v e l o p m e n t of b i o l o g i c a l s c r e e n i n g t e s t s has r e c e i v e d much a t t e n t i o n o v e r t h e p a s t few y e a r s , and s e v e r a l t e s t s ( e . g . , t h e Ames t e s t ) h a v e become w i d e l y u s e d by many l a b o r a t o r i e s . Surveys of Environmental Impacts. F i e l d s u r v e y methods f o c u s on a s s e s s i n g changes i n t h e c o n d i t i o n o f e n t i r e p o p u l a t i o n s and e c o l o g i c a l community f u n c t i o n s ( e . g . , p e s t s p e c i e s p r o l i f e r a t i o n , s p e c i e s d i v e r s i t y , l i t t e r d e c o m p o s i t i o n r a t e , changes i n t h e r a t e of p r i m a r y p r o d u c t i o n ) . These methods u n d e r c e r t a i n c i r c u m s t a n c e s may r e l a t e e f f e c t s t o s p e c i f i c p o l l u t a n t s o u r c e s , b u t most f r e q u e n t l y t h e y a r e u s e d t o i n d i c a t e t h a t a p r o b l e m does exist. A c u r r e n t a p p l i c a t i o n o f s u r v e y methods b e i n g d e v e l o p e d e m p h a s i z e s i d e n t i f i c a t i o n of i n d i g e n o u s s p e c i e s t o s e r v e as s u r r o g a t e s f o r a p o r t i o n of t h e e c o s y s t e m . Monitoring f o r Bioaccumulation or B i o e f f e c t s . Biological methods can be u s e d s i m p l y t o i n d i c a t e t h e p r e s e n c e of a p o l l u t a n t at a study l o c a t i o n . C h e m i c a l a n a l y s i s can i d e n t i f y t h e t y p e o f p o l l u t a n t p r e s e n t i n b i o l o g i c a l s p e c i e s as shown i n F i g u r e 10. However, u n l e s s t h e r e i s an e x t e n s i v e d a t a b a s e c o n c e r n i n g u p t a k e r a t e s , s u c h an a p p r o a c h w i l l n o t r e v e a l p o l l u t a n t c o n c e n t r a t i o n s i n the a r e a . B i o l o g i c a l e f f e c t s such as enzyme i n h i b i t i o n can a l s o be u s e d i n some c a s e s t o i n d i c a t e t h e t y p e s of c h e m i c a l s i n t h e a r e a ( e . g . , i n h i b i t i o n o f r e d b l o o d c e l l a c e t y l c h o l i n e s t e r a s e f o l l o w i n g an a n i m a l ' s c o n t a c t w i t h o r g a n o p h o s p h o r u s c h e m i c a l s ) . The d e t e c t i o n of m e t a b o l i c p r o d u c t s i n body f l u i d s m i g h t a l s o be u s e d t o i n v e s t i g a t e t h e b i o l o g i c a l


Long and Schweitzer; Risk Assessment at Hazardous Waste Sites ACS Symposium Series; American Chemical Society: Washington, DC, 1982. XXX XXX

XX XX XX

Lead

Mercury

Nickel

Selenium

Tin

Figure 10.

xx—Moderate.

XXX

X

X

XXX

XXX

X

X

XX

X

X

XXX

X

XXX

XXX

xxx—High to very high.

XX

XXX

XXX

XXX

XXX

XXX

XXX

XXX

X

X

XX

X

Mosses, lichens, and algae

Bioaccumulation and bioconcentration of trace elements.

x—Low or limited.

X

XXX

XXX

XXX

Copper

Vanadium

X

XXX

X

XXX

XXX

Cobalt

XXX

XXX

XX

XXX

XXX

XX

X

Chromium

X

Boron

XXX

X

X

Higher plants

XXX

X

Mollusks, Crustacea, and lower animals

Cadmium

X

XX

X

Beryllium

Arsenic

Antimony

Mammals, birds, and fish


90

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u p t a k e of some compounds ( e . g . , t h e p r e s e n c e of c h l o r i n a t e d p h e n o l s i n u r i n e f o l l o w i n g u p t a k e of c h l o r i n a t e d h y d r o c a r b o n s ) .


P r o v i d i n g More M e a n i n g f u l M o n i t o r i n g D a t a f o r H e a l t h A s s e s s m e n t s Even w i t h r a p i d a d v a n c e s i n t h e s t a t e - o f - t h e - a r t of m o n i t o r i n g t e c h n o l o g i e s many of t h e p r o b l e m s of e f f e c t i v e l y m e s h i n g m o n i t o r i n g d a t a w i t h d a t a on h e a l t h e f f e c t s w i l l c o n t i n u e t o persist. U n d o u b t e d l y , t h e p a s t a p p r o a c h e s of c o l o c a t i n g m o n i t o r i n g and h e a l t h s t u d i e s w i l l c o n t i n u e . These a p p r o a c h e s r e l y on m o n i t o r i n g a c t i v i t i e s t o c l a r i f y e x p o s u r e s t o s p e c i f i c c h e m i c a l s and on h e a l t h s t u d i e s e i t h e r t o a s s e s s t h e a c c u m u l a t i o n o f t h e s e c h e m i c a l s i n human p o p u l a t i o n s o r t o c l a r i f y t h e h e a l t h e f f e c t s w h i c h c o u l d be r e a s o n a b l y a t t r i b u t e d t o c h e m i c a l e x p o sures. Good e x a m p l e s of t h e s e two a p p r o a c h e s a r e the e f f o r t s i n t h e U n i t e d S t a t e s and a b r o a d t o ( a ) r e l a t e b l o o d l e v e l s o f cadmium and l e a d b o t h t o e x p o s u r e s and t o e f f e c t s and ( b ) r e l a t e c e r t a i n t y p e s of e x p o s u r e s t o o r g a n i c c h e m i c a l s t o i n c r e a s e d i n c i d e n c e of c a n c e r . O b v i o u s l y , u n c e r t a i n t i e s abound i n s u c h e f f o r t s p a r t i c u l a r l y with regard to characterizing population a c t i v i t y p a t t e r n s o v e r an e x t e n d e d p e r i o d of t i m e as t h e b a s i s for exposure e s t i m a t e s . T u r n i n g more d i r e c t l y t o the i s s u e s s u r r o u n d i n g h a z a r d o u s w a s t e s i t e s , t h e s c i e n t i f i c community has an u n u s u a l o p p o r t u n i t y t o d e v e l o p and a p p l y i m p r o v e d a p p r o a c h e s f o r c o u p l i n g e n v i r o n m e n t a l c h e m i s t r y and t h e h e a l t h s c i e n c e s . W h i l e a n s w e r s may be needed t o d a y , t h e same t y p e s of a n s w e r s w i l l be needed f o r many d e c a d e s . T h u s , we s h o u l d t h i n k i n terms of l o n g - r a n g e r e s e a r c h p r o g r a m s t h a t w i l l p r o v i d e a v a r i e t y of i n t e r i m a n s w e r s — p r o g r a m s t h a t can r e l a t e measurements i n s o i l , w a t e r , a i r , and t h e f o o d c h a i n i n m e a n i n g f u l ways t o n e a r - t e r m and l o n g - t e r m e f f e c t s i n people. F o r e x a m p l e , how can m o n i t o r i n g h e l p us p r e d i c t w i t h some c o n f i d e n c e t h e r a t e s a t w h i c h c h e m i c a l s u n d e r a v a r i e t y of c o n d i t i o n s w i l l migrate toward people? Can a g g r e g a t i o n s o f d a t a on c l a s s e s of c h e m i c a l s d e t e c t e d a t t r a c e l e v e l s p r o v i d e a meaningful basis f o r i n v e s t i g a t i n g p o s s i b l e e f f e c t s ? Can p r a c t i c a l m o n i t o r i n g s y s t e m s be d e v e l o p e d w h i c h p r o v i d e e x p o s u r e d a t a on i n d i v i d u a l s as i s o f t e n done u s i n g f i l m badges and thermoluminescent d o s i m e t e r s i n the r a d i a t i o n f i e l d ? Finally, can measurements of v e r y l o w l e v e l s of c h e m i c a l s o r of t h e e a r l y s t a g e s of b i o c h e m i c a l r e a c t i o n s i n p e o p l e o r a n i m a l s s e r v e as e a r l y w a r n i n g i n d i c a t o r s of a d v e r s e h e a l t h e f f e c t s t h a t c o u l d r e s u l t from f u r t h e r exposures?


7.

SCHWEITZER


91


Literature Cited 1.

"Remedial A c t i o n s at Hazardous Waste S i t e s : Survey and Case S t u d i e s , " United States Environmental P r o t e c t i o n Agency 430/9-81-05.

2.

" N a t i o n a l Conference on Management of U n c o n t r o l l e d Waste Sites," United States Environmental P r o t e c t i o n Agency/ Hazardous Waste M a t e r i a l C o n t r o l Research Institute, October 28, 1981, pp. 86, 87.

RECEIVED

June 16,

1982.


Risk Assessment at Hazardous Waste Sites - American Chemical

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