! . M i i - t l i l i n g , R. . m < l u . K . u i s o M . "Accelerated M n x - i . i l i / . i iPentachlorophenol in Soil upon lnociil.ilion \ \ n l i Mn-nlniili-riiiiii ili/nni/i/itnolicum PC1M and Sphingomonas chlorophenolica KA.'." . I / ' / ' / I iii'inmMicrobiol. 1996, 62: 4361-66.

3. Mannisto, M. and M. Tiirola. "Diversity o fd i lo rop l i rno l ik-^r.ulmi', l > , i . li'rldisolated from contaminated boreal groundwater." Arch. Mnrutnol \<>'>>)171: 189-197.

4. Leontievsky, A. A. and N. M. Myasoedova. "Adaptat ion o l ' i l i e \ v l i n r mibasidiomycete Panus tigrinus for transformation of high c o i H c n i r . i l i c n i ' , < i lchlorophenols." Apfl. Microbiol. Biotecbnol. 2002, 59: 599-604.

5. Reddy, G. and M. Gold. "Purification and Characterization o f C i l i n . n lConjugate Reductase: A Component of the Tetrachlorohydroi] n.Reductive Dehalogenase System from Phctnerochaete chrysosforium." / I n / /Biocbem. Biopbys. 2001, 391: 271-77.

6. Apajalahti, J. and M. Salkinoja-Salonen. "Dechlorination and /nunHydroxylation of Polychlorinated Phenols by Khodococcus chloropbciiolii u< "]. Bacterial. 1987, 169: 675-81.

7. Apajalahti, J. and M. Salkinoja-Salonen. "Complete Dechlorination . . ITetrachlrohydroquinone by Cell Extracts of Pentachlorophenol I n i l i u i , IRhodococcus chlorophenolicus." /. Bacterial. 1987, 169: 5125-30.

READING RESPONSES1. As Arianne Folkema notes in her introduction, students find themselves in

an odd position when they write summaries of research: these are usuallywritten by an expert in a field of research, not a novice. Compare the firstthree paragraphs of Folkema's review with Alexander's. List the similaritiesand the differences that you find. For each difference, consider if it might bea result of Folkema's status as a novice researcher.

2. In her review, Folkema typically includes more information about theresearch she's summarizing than Alexander does. What additional informa-tion does Folkema include? Who might value this information? Why isit/isn't it worth including?

3. If you were a professor of chemistry, would you require students to includea review of literature in their research reports? Provide a set of reasons tosupport your answer.

PUBLIC WRITING IN CHEMISTRY

Introduction

The publication of Rachel Carson's Silent Spring is often credited with launching the environmental movement. Carson, after earning a master's degree inzoology, wrote radio scripts for the U.S. Bureau of Fisheries, later becoming anaquatic biologist and then chief editor of publications for the bureau. She turnedto full-time independent writing, and, after four years of research for the book,

| l l l | i | i > , l i c ( l Sili-iil S/ir/ini in I ' X ) J . C h e n i i i . i l * < > n i | > . i m < • . I n c i l to p u \ r i i l i t s, . i M i . i n . i n , .mil Carson w.is t h r e a t e n e d w i i h l a w s u i t s . i i u l .mused < > l hnnt ' ,

i . i n . i l , .111 " l iys le rk- . i l woman," and .1 c o m m u n i s t . I t became, nonl i l l i r l i H I in ternat ional bestseller.

/ S/iriiyi begins w i t h a (hree-page chapter e n t i t l e d "A I ' . i b l e lot• M . I U " The chapter ' s opening sentence, "There once was a town in t h enl \ I I I C I H , i where all l ife seemed to l ive in harmony with its surroundings"n n l i - i s i n t o a story of an idyllic town that is beset by un imaginab le bio

.1 horrors—birds and bees disappear, vegetation withers and dies. Carson

. i , l . s t h e chapter by tel l ing us that no town had suffered all the bl ight t l i . i ti . H i d upon her fictional town but that "every one of these disasters has

I - h . ippened somewhere." The final paragraph of the chapter reads, "WhatIn .idv silenced the voices of spring in countless towns in America? This book

in i n . n i p t to explain."I 1 1 . opening chapter tells us that Carson is offering a natural history—a his

• i n.n nre assaulted by humans. It is very important to recognize that historyi I i n . I nl summary, here enlivened in skin and bone and bark and root. Through

. 1 I ' .mi ion Carson's "review" of the environmental record enriches our senseIM usefulness of summary.

I I n i c arc obvious differences between this piece and a scientific review. I t isu l i - i l i n thorough research, but the references sit quietly offstage so as not to

I I. n i he text with footnotes," as Carson explains. It is passionate and personalI i iii ' .nage such as "fantastic," "menace," and "endless problems").

\ . i t h e kinship to a scientific review is evident. The first sixteen chapters ol I In -• I r . i uss the evidence that pesticide use is damaging nature. The last chapter,

I I n < ) iher Road," answers the "what next?" question. In it she discusses the ben. In nl biological control over pests, identifying several particular methods, each

I 1 n 11 has now been the subject of scientific research. In other words, Silenty / / / / / ; lollows the form and purpose of a review essay, and it brought about thei.. I . I .h.iping results that review writers hope for.

Realms of the Soil

Rachel Carson

( h , i | i i i i 5, Silent Spring, 1962, , . The problem that concerns us here is one that has received little con

i . l i i n : What happens to these incredibly numerous and vitally necessaryl i i l u b i i a n t s of the soil [worms, microbes, and all life forms that inhabit thelull | when poisonous chemicals are carried down into their world, ei ther( H I i n d u c e d directly as soil "sterilants" or borne on the rain that has pickedH|i .1 l e tha l contamination as it filters through the leaf canopy of foresti n . I m i l i a r d and cropland? Is it reasonable to suppose that we can apply a

broad-spectrum i n s ec t i c i de to k i l l the |MI ITO\ \ ing l a r v a l stages of ,i uopdestroying insect, f o r example , w i t h o u t also k i l l i n g t h e "good" i n s e c t s \ \ l n > - .function may be the essential one of breaking down organic m a l l e i ' ? Or can \Muse a nonspecific fungicide without also killing the fungi lh . i t i n h a b i t i l i e iof many trees in a beneficial association that aids the tree in e x t r a c t i n g n i i i nents from the soil?

The plain truth is that this critically important subject of the ecology ol i h >soil has been largely neglected even by scientists and almost completely i g m m .1by control men. Chemical control of insects seems to have proceeded on i l nassumption that the soil could and would sustain any amount of insul t via i l uintroduction of poisons without striking back. The very nature of the world i > lthe soil has been largely ignored.

From the few studies that have been made, a picture of the impact of 'pcsi icides on the soil is slowly emerging. It is not surprising that the studies arc m i lalways in agreement, for soil types vary so enormously that what causes damagein one may be innocuous in another. Light sandy soils suffer far more heavily i h . u ihumus types. Combinations of chemicals seem to do more harm than separateapplications. Despite the varying results, enough solid evidence of harm is aci umulating to cause apprehension on the part of many scientists.

Under some conditions, the chemical conversions and transformations i l i . nie at the very heart of the living world are affected. Nitrification, which make*ionospheric nitrogen available to plants, is an example. The herbicide 2,4 I):auses a temporary interruption of nitrification. In recent experiments in Florid.i,indane, heptachlor, and BHC (benzene hexachloride) reduced nitrification a l i e iDnly two weeks in soil; BHC and DDT had significantly detrimental effects a ye.nifter treatment. In other experiments BHC, aldrin, lindane, heptachlor, and DO I)ill prevented nitrogen-fixing bacteria from forming the necessary root nodules oneguminous plants. A curious but beneficial relation between fungi and the rootsif higher plants is seriously disrupted.

Sometimes the problem is one of upsetting that delicate balance of popul.iions by which nature accomplishes far-reaching aims. Explosive increases in somednds of soil organisms have occurred when others have been reduced by insecn:ides, disturbing the relation of predator to prey. Such changes could easily a l t e rhe metabolic activity of the soil and affect its productivity. They could also meanhat potentially harmful organisms, formerly held in check, could escape from thenlatural controls and rise to pest status.

One of the most important things to remember about insecticides in soil is their3iig persistence, measured not in months but in years. Aldrin has been recoveredfter four years, both as traces and more abundantly as converted to dieldrin.inough toxaphene remains in sandy soil ten years after its application to lull termites.Senzene hexachloride persists at least eleven years; heptachlor or a more toxiilerived chemical, at least nine. Chlordane has been recovered twelve years after i t spplication, in the amount of 15 per cent of the original quantity.

Seemingly moderate applications of insecticides over a period of years may build:p fantastic quantities in soil. Since the chlorinated hydrocarbons are persistent and

l.i mi)'., i - .uh appl icat ion is nicicly .idded lo the <|i i .mli lv i em.lining limn [he

M The old legend lh.il "a pound ol' DDT lo the .u re is harmless"i.. 'i I n iir. 1 1 spraying is repealed. I'oialo soils have been found lo contain up lo

muds ol DDT per acre, corn soils up to 19. A cranberry bog under study eoni | i pounds lo the acre. Soils from apple orchards seem to reach the peak olmi i i, \vi ih DDT accumulating at a rate that almost keeps pace with ils rale

mi il .ipplkaiion. Kveii in a single season, with orchards sprayed four or moreI >D I usidues may build up to peaks of 30 to 50 pounds to the acre; under

',. up In 1 I 3 pounds.UK provides a classic case of the virtually permanent poisoning of the

lili"iir.h arsenic as a spray on growing tobacco has been largely replacedn i l i e i i c organic insecticides since the mid-'40s, the arsenic content of

Hi i ninth- from American-grown tobacco increased more than 300 per centn i he years 1932 and 1952. Later studies have revealed increases of as

l i i < > ( ) ( ) per cent. Dr. Henry S. Satterlee, an authority on arsenic toxicoli i hat although organic insecticides have been largely substituted for

m i I n lobacco plants continue to pick up the old poison, for the soils of. . p lan ta t ions are now thoroughly impregnated with residues of a heavy

. . I . H i v e l y insoluble poison, arsenate of lead. This will continue to releasen. i n soluble form. The soil of a large proportion of the land planted to

... IMS been subjected to "cumulative and well-nigh permanent poison, d ing to Dr. Satterlee. Tobacco grown in the eastern Mediterranean

UK \\ here arsenical insecticides are not used has shown no such increase in• 'iiient.ire therefore confronted with a second problem. We must not only be

I with what is happening to the soil; we must wonder to what extenti . i . l . . . .ire absorbed from contaminated soils and introduced into plant

Much depends on the type of soil, the crop, and the nature and concenin i > l I he insecticides. Soil high in organic matter releases smaller quantities oln . ih.m others. Carrots absorb more insecticide than any other crop studied;

. I n n i i ca l used happens to be lindane, carrots actually accumulate highern i i . i i i o n s than are present in the soil. In the future it may become necessary

n >l \v .e soils for insecticides before planting certain food crops. Otherwise eveni \ . d crops may take up enough insecticide merely from the soil to render. n i l i i for market.

I Ins very sort of contamination has created endless problems for at leastI 1 id ing manufacturer of baby foods who has been unwilling to buy any

vegetables on which toxic insecticides have been used. The chemicalmsed him the most trouble was benzene hexachloride (BHC), which is

• .1 • n up by the roots and tubers of plants, advertising its presence by a musty. m l odor. Sweet potatoes grown on California fields where BHC had been

I i \ \ o years earlier contained residues and had to be rejected. In one year,I n . h the firm had contracted in South Carolina for its total requirements

i eel potatoes, so large a proportion of the acreage was found to bei i i i i n . i i e d that the company was forced to buy in the open market at a

considerable f i n a n c i a l loss. Over l l i e years a v a r i e t y o f f r u i t s a n d \ r j ' . c t . i l > l <grown in various states, have had to lie re jected. The most s t u b b o r n p iob l . n ,were concerned with peanuts. In the southern states p e a n u t s are u s u a l l v r , i < i u nin rotation with cotton, on which BHC is extensively used. P e a n u t s i ' , n> \ \ n l . i i . iin this soil, pick up considerable amounts of the insecticide. A c t u a l l y , < > n l \ itrace is enough to incorporate the telltale musty odor and taste. The c h c m u . i lpenetrates the nuts and cannot be removed. Processing, far from rcmovim-, t i nmustiness, sometimes accentuates it. The only course open to a m a n n f a c idetermined to exclude BHC residues is to reject all produce treated w i t h i l nchemical or grown on soils contaminated with it.

Sometimes the menace is to the crop itself—a menace that remains as lour, ithe insecticide contamination is in the soil. Some insecticides affect sensitive p l . m isuch as beans, wheat, barley, or rye, retarding root development or dcpressiti]growth of seedlings. The experience of the hop growers in Washington and Idahois an example. During the spring of 1955 many of these growers undcrlool >large-scale program to control the strawberry root weevil, whose larvae h . n lbecome abundant on the roots of the hops. On the advice of agricultural expert*and insecticide manufacturers, they chose heptachlor as the control agent. W i t h i na year after the heptachlor was applied, the vines in the treated yards were w i l i m rand dying. In the untreated fields there was no trouble; the damage stopped at t i nborder between treated and untreated fields. The hills were replanted at gre.ilexpense, but in another year the new roots, too, were found to be dead. Four ye.irnlater the soil still contained heptachlor, and scientists were unable to predict h i mlong it would remain poisonous, or to recommend any procedure for correct in^the condition. The federal Department of Agriculture, which as late as M a n h1959 found itself in the anomalous position of declaring heptachlor to be acceptable for use on hops in the form of a soil treatment, belatedly withdrew its regiatration for such use. Meanwhile, the hop growers sought what redress they coulilin the courts.

As applications of pesticides continue and the virtually indestructible residuescontinue to build up in the soil, it is almost certain that we are heading for trouble. This was the consensus of a group of specialists who met at SyracuseUniversity in 1960 to discuss the ecology of the soil. These men summed up i h >hazards of using "such potent and little understood tools" as chemicals andradiation: "A few false moves on the part of man may result in destruction of soilproductivity and the arthropods may well take over."

READING RESPONSES1. Carson opens her chapter with three questions. Interestingly, each question

serves a distinct function in her essay. Re-read each question and analyze

t i l l ' ( h.lplci I)C'M Il l i i ' K III IIIhow ih.it question relates to the t < >D| (MI 1 1 question.When < arson discusses particular topics, she describes first old ways ofthinking and then new research. Choose one paragraph that contains bothi ild ,md new information. Analyze the purpose of old information in thisp.ti.Hjrdph. What "work" does it do?i iirson's chapter summarizes previous scientific research just as Alexander'si loos. But Carson is writing to a general audience, not other experts in theIli'ld. Compare Alexander's style with Carson's. What stylistic strategies doesi iirson use to make her essay more readable?

M< H< I , WKITING IN CHEMISTRY

< M ! I K l i o n

i i i h i • l i n i ' . s in this chapter have focused on issues related to soil contaminated byi > iK t h a t humans have purposely, or in some cases, accidentally applied.

" a led soil and water are significant contributors to the exposure ofin in toxic substances, but natural and man-made disasters also result inin • \piisure to toxins. This reading reviews scientific data regarding the types

i i c , and the consequences of that exposure, caused by the attack on theR H'li I 1 1 ade Center. The essay is written by a large team of scientists from seven

MIS. The intended audience is toxicologists and other scientists who study' H i \posure to toxins, and, to a lesser extent, physicians who are interested in' m m mal exposure to toxins.

I l n review essay documents the types and amounts of toxins that werei i l n no the atmosphere as a result of the disaster and the observed health

| i n nces of human exposure to those toxins. Most of the information regard-1 1 n ivpes and amounts of toxins produced during the disaster has been' • . I 1 1 1 mi this abridged version because it is highly technical and difficult for a

I " n to follow. We include, however, studies of the health consequences off | | u iKi iK ' to those toxins.

I In review follows a logical argument: (1) the types and amounts of tox-i I'i'li ased as a result of the disaster; (2) the health consequences observed;I) till1 consequent need to continue monitoring the health of those exposed

H t i n t o x i n s . In other words, its structure is typical of a review essay, movingi nmmary of what has been learned to a projection of what yet needs to

I n i i h l u - d .