Document wrby901Dv5OL7awYrzkGZe11J

LONDON "Times", Dec. 17, 1970 I 3 Science Report Pollution: Sewage killing marine life The way in which scveal tons of is earned bv boat to the estuary , the industrial chemicals polychlor- and dumped in deep water six mated biphenyls, or PC)Is arc he- . miles south of Crarroch Head. Isle mg dumped each year in coastal of Bute. waters round Britain is outlined in It appears that it ,,is in this pec - a report from the Fresnwater . Fisheries I-aboratory. Pitlochry. Scotland. It provides the posih e explana tion of how this subslan' e has been able to accumulate c fishore in sufficient quantities to h rm marine life. ccss that quantities of biphcnvls ar being dispersed in the sea. Prelim inary estimates suggest that about a ton of PCBs is being dumped in the Clyde estuary this way. Similar disposal operations for Manchester and London indicate that similar quantities are being ' Anxiety about the spread of I PCBs has grown over tie past two years with the detection of harni ful leVels in sea birds, seals and ; other marine life. These chemicals ; have been a contributory cause of !lhe death of large populations of ;'somc wildlife species. i PCBs arc produced lor a wide [variety of industrial processes. The [mod likely cause of tlieir spread ; 'seemed to be 'he discharge of fac-' j tory effluent into rivers and thence down to estuaries. But it has been j difficult to reconcile this seemingly ' 'straightforward event with the find- , ling of biphenyl substances in ccr- ; ;tam cases of wildlife death. 'j | The investigation at Pitlochry t : started from an analysis of marine ; i fish and molluscs in Scottish waters I I that showed the highest residues i j of PCBs ro be in samples, taken j ! from the Firth of Clyde. ! j Attempts were made to trace | the source of pollution by exam- I ' ining the vanous waters discharged j into the riser at intervals along the j CK-dc to the centre of Glasgow. \ No detectable amounts wcie j found; nor were any appresiabie ! levels shown in an examination of j the cl fluent from the trunk sewers i carrying the bulk of treated waste I discharged from many hundreds of . factories. | In the roport Mr. .V V. Holden j - describes how the investigation then i turned to studying the sewago [ sludge from treatment works which j dumped in the northern Irish Sea ana the Thames estuary. . Mr. Koldcn suggests Wut some PCBs may be entering the sea d.rectly in areas where- waste is discharged offshore w.thoul treat ment, and the disposal of sludge on land could lead to PCB residues entering the terrestrial ecosystem by transfer through food chains. By Pearce Wright, Science Corres pondent. Nature. VoL 22*. Dec. 19. ' DSW 282627 STLCOPCB4063956