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the Health Department on the other (see paragraph 33), and the evidence showed that the Harbour Board and the Health Department propose taking whatever action is found necessary to ensure that these standards will be complied with and that they will be altered if they are found to be too low or unsatisfactory in any other way. (18) A good deal of attention was devoted to this subject at the hearing, and in particular there was considerable criticism of the adequacy of the float tests which have been carried out by the Harbour Board to determine the nature of the movement of the waters in the vicinity of. Brown's Island under the influence of tides, winds, and currents. We are satisfied that the tests support the opinion that there is no reasonable possibility of any effluent which is discharged from the outfall proposed to be constructed reaching any beach within a period of four hours, and that within that period the purification of the effluent to the prescribed standards will have been completed. It should be pointed out, however, that even if it should prove from the periodical tests which must be made to ensure compliance with the standards of purity that the effluent is not being purified sufficiently rapidly by dilution, the Board will be under the obligation of providing more complete secondary treatment in order to reduce the impurity factor. It is apparent, we think, that much of the criticism of the float tests has arisen from a want of appreciation of the effects of the sun and the movement of water as purification agents. (19) The bacteriological standards which are included in the standards of purity pay full regard, in our opinion, to the need for considering the reduction of the bacterial content of the effluent in addition to taking into account the amount of dilution obtained and the availability of dissolved oxygen in the diluting waters. There is considerable divergence in the standards which have been prescribed in the United States and other countries and it is difficult to determine what standards should be adopted. However, those prescribed for the Brown's Island area are as strict as the most conservative of the United States standards for actual bathing waters, and we consider, therefore, that there can be no doubt that they will be entirely satisfactory for samples taken from water which will be further diluted and purified before it reaches the bathing beaches. (20) We consider, also, that there is no justification for the fears that were expressed that the Harbour Board and the Health Department may fail to insist on compliance with the prescribed standards of purity. (21) While the Harbour Board and the Health Department have been the authorities actually -concerned with the prevention of harbour pollution at Auckland, the Marine Department also has certain statutory obligations in connection with the matter, and we were informed by Mr. D. F. Hobbs, the Department's Senior Fishery Officer, who gave evidence before us on behalf of the Department, that in recent years it has taken an active interest in the subject of the reduction of pollution in harbours and in inland waters and other waters. We were also informed by Mr. Hobbs that an inter-departmental Pollution Committee, of which he is a member as the representative of the Marine Department, has recently, among other activities, conducted a fact-finding survey on the state of pollution of inland and coastal waters. The final report of this Committee was made available to us, and one of its recommendations is that a national pollution authority should be created by statute which would act as an advisory body on pollution questions. The Marine Department suggested that the inter-departmental Committee (or the statutory authority if the recommendation is given effect) should be given power to review any standards of purity that may be prescribed for the Auckland harbours. We have given careful consideration to this suggestion, which it was urged would have the advantage of placing the responsibility on an authority which would be unlikely to be affected by local pressure and which would have the benefit of the technical resources of all Government Departments. We consider, however, that there is much to be said for leaving the primary responsibility with the Auckland Harbour

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