fish are to be avoided. This was pointedly brought out during the winter of 1924-25 when a series of typhoid outbreaks was traced to contaminated oysters which had been shipped from one packer to several large cities in the United States (Lumsden et al. 1925). Following this, basic control patterns were drawn up between the shellfish industry, the State health departments, and the United States Public Health Service. The Bureau of Chemistry of the United States Department of Agriculture (now the Food and Drug Administration of the Federal Security Agency) and the Bureau of Fisheries of the United States Department of Commerce (now the Fish and Wildlife Service of the United States Department of the Interior) were involved in this early planning.

Under this arrangement, the Public Health Service develops recommended standards and manuals of operating practice (Anonymous 1946) which are applied by the shellfish industry under the supervision of the State shellfish-control agencies. The Public Health Service evaluates these control procedures of the State agencies on a continuing basis. When satisfied that proper controls are exerted by the States, the Public Health Service publishes routine lists of shellfish shippers who are certified by the individual State shellfish-control authority, usually the State department of health. These lists are distributed widely throughout the United States to health officials and others who may be concerned with the problem of market quality of raw shellfish. In practice, a shellfish shipper finds it necessary to be properly certified in order to be able to market his products in most parts of the United States.

As in the case of most of the shellfish-producing States, the States bordering on the Gulf of Mexico divide the controls over shellfish operation between two State agencies. The purely sanitary aspects of the control program, including surveillance over the sanitary quality of shellfishgrowing beds and operation of packing houses, rest with the individual State health department. Actual control of shellfish-growing areas which are closed to commercial fishing, on the other hand, is handled by some other State agency. In the case of Florida, the State Board of Conservation bears this responsibility, while in Alabama the State Conservation Department is involved.

The Mississippi Seafood Commission patrols growing areas closed because of pollution in that State. In Louisiana, the Division of Oysters and Water Bottoms of the Department of Wildlife and Fisheries assists the State Department of Health in patrolling the closed areas. The Texas Game and Fish Commission cooperates with the Texas State Department of Health on patrol work in that State.

In the following pages areas closed to commercial harvesting of shellfish are described specifically on the basis of information resulting from sanitary and bacteriological surveys conducted by the several State departments of health. In most instances the results of such surveys are contained in reports cited in an annotated bibliography (Anonymous 1952).

SUMMARY OF WATER POLLUTION DATA

The summary set forth below is based entirely upon readily available information from various sources, and no investigations have been made. specifically for the purpose of this report. The data therefore are admittedly incomplete. This is particularly true of industries and pollution caused by their wastes. Gaps in the data are nonetheless significant and point the direction of necessary future work.

Because of tremendous quantities of available dilution water, it is unlikely that pollutional wastes originating in the coastal area have appreciable effects upon either water or resources in the open waters of the Gulf. Reports of such effects have not been forthcoming, and no intensive investigations appear to have been made. On the basis of information now available, however, there are at least 369 separate sources of pollution that may have localized effects upon coastal waters of the Gulf or the lower reaches of tributary streams. One hundred ninety-seven of these are municipalities, sewer districts and institutions that utilize tributary watercourses, sloughs, lagoons, estuaries, and bays to dispose of their wastes. The sewer systems concerned serve a total of about 3 million persons. Industrial wastes of unknown character and quantity are also discharged to these sewer systems. Sewage from 35 municipalities with a total of 755,000 sewered inhabitants reaches surface waters without treatment of any kind. Numerical data on treatment loads or plant efficiencies are not

available for the 162 municipalities that provide treatment so that the actual total discharge for all municipalities is not known.

Because summary data on industrial wastes are not available for Texas and are less complete than municipal data for other Gulf States the extent of the industrial waste pollution problem is not fully shown. On the basis of present knowledge, 173 industrial plants of various kinds discharge treated or untreated waste directly to surface waters. These plants include production of pulp and paper, sugar, petroleum and its products, processed food, chemicals, and metals. Their wastes are of many different kinds. One hundred fifteen plants produce organic wastes, but the quantity can be estimated with confidence for only five, which discharge a total of 76,000 population equivalent.3 Inorganic wastes are produced by 67 plants, and the type of wastes from five plants is not known. A number of plants have process wastes with appreciable quantities of both organic and inorganic components. Considerable additional information is needed before an estimate of the total quantity of waste from all sources can be made.

Although 82 percent of the municipalities along the Gulf coast that have sewer systems also have sewage treatment facilities, at least 25 percent of

Sewered population equivalent of industrial waste is based on 0.167 pounds of 5-day, 20° C. biochemical oxygen demand per capita per day in municipal sewage.

the total sewered population is not served by such facilities. In addition, recent phenomenal population growth and obsolescence of equipment have made 60 of the 162 existing sewage treatment facilities physically inadequate to satisfactorily treat the waste they receive.

Definite information on provision of pollution prevention measures or practices by industries is available for only about one-third of the plants. Less than one-third of these have treatment facilities of which two have insufficient capacity and three have unsatisfactory operation.

An increase of approximately 14 percent in the number of municipal treatment facilities will be necessary to help bring about an adequate pollution abatement program for the receiving waters. These new facilities, which are 22 in number, would serve about 130,000 people. In addition, 37 percent of the existing facilities need either to be replaced by new plants or enlarged and remodeled to handle existing loads in an adequate manner. These plants now serve about 272,000

persons.

DAMAGES TO RESOURCES CAUSED BY

POLLUTION

Coastal waters of the Gulf are subjected to pollution directly by discharges from waterfront cities and industries and indirectly through polluted river systems. With this the case, the effects of pollution are not spread uniformly along the coast; they are restricted to localized areas where population and industries are concentrated, where rapid waste dilution is limited by physiographic features, and where exploitable resources occur. It is obvious from this that the susceptible resources include the fin fishes, shrimp, crabs, and oysters that depend upon estuarine existence for at least a part of their life; and near centers of population-the sport fishing and boating waters, bathing beaches and recreational areas, and waterfront property that depreciates as pollution increases.

Available data on sources and kinds of pollution imply notable potentialities for causing damages to resources in restricted areas. In spite of this, observed effects upon the resources have not been of sufficient magnitude to stimulate the required studies aimed at actually evaluating the extent of damage. Surveys and closure of shellfish produc

ing areas because of bacterial contamination give only a fair suggestion of one source of economic loss. Lack of sufficient data makes it impossible to evaluate the full damages from pollution along the Gulf coast.

For purposes of this report the Gulf Coast from Key West to the Rio Grande has been divided into 23 separate drainage areas. Localized pollution damages of some kind or other occur in most of these areas. Almost one-half of them, representing waters of each of the Gulf States, have shellfish areas that are closed to commercial fishing because of pollution. A number of otherwise popular bathing beaches located in at least seven different areas have been made unfit for use. Outright destruction of fish and impairment of sport fishing waters have occurred locally at many points along the coast. Nuisance conditions, losses in property values, effects of sediment deposition, and other more subtle changes that accompany pollution contribute to the total damages.

These impairments of water quality and deleterious effects upon specific resources of the Gulf represent both tangible and intangible values.

See figs. 73 and 74, pp. 562 and 563.

of pollution in the designated categories occurring in the shaded area of the State Industrial data not available for the State of Texas.

FIGURE 73.-Sources of pollution and existing treatment facilities.