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Toxics are poisonous compounds that have been identified as being harmful to human health and the environment. Discharges of toxic water pollutants into the surface waters of the state are a mounting public concern. Some toxics are soluble in water and pose a threat to human health if the water is used for drinking or swimming. Other toxics are not soluble in water, but may become attached to sediment and be consumed by aquatic life forms, thereby entering into the food chain. This process, known as bioaccumulation, puts humans at risk if the toxics become concentrated in higher life forms like fish.
Not until 1988 did limits on toxics became a major part of the water quality standards. Even now, though, if a facility discharges a substance classified as toxic under water quality standards set in 1991, that substance may not have been incorporated into the facility's original discharge permit. Thus, until the permit comes up for renewal, toxics that violate state standards may be released into state waters.(34) In addition, state water quality standards address only 61 specific toxic compounds out of thousands of potential compounds. Thus, many chemicals could be directly discharged into Texas' surface waters without any discharge permit limits.
Finally, some industries route their toxic discharges through publicly-owned treatment works (POTWs), which are often not designed to remove toxic chemicals and metals. While cities that discharge more than one million gallons a day are required to pretreat any wastewater that comes from industries, smaller cities are not. Most cities, large or small, require that the industrial facilities that release toxics through publicly-owned treatment works pretreat their wastewater to limit toxins. In addition, under federal law, 21 categories of industries must pretreat their waste to "best available technology" before discharging waste to a public wastewater treatment plant.(35) However, neither industrial nor municipal pretreatment programs are universally applied or enforced.(36)
One of the best sources of information for the amount of toxics entering Texas waters is the Toxics Release Inventory (TRI). Under the federal Superfund Authorization and Renewal Act, manufacturing companies with 10 or more employees that use or manufacture more than 25,000 pounds per year of any of more than 320 toxic chemicals or chemical compounds must file an annual report with the state. This report documents their releases of toxics to the air, water, and land and details any transfers of toxics to hazardous waste facilities and publicly-owned wastewater treatment plants.(37)
Though the Toxics Release Inventory is a useful tool, it gives only a partial picture of toxic releases into the environment. The program requires only manufacturing facilities to report, leaving out other industries which produce toxics and publicly-owned facilities like utilities. Also, there are more than 320 toxic compounds, and the Toxics ReleaseInventory does not track their releases.(38)
Texas manufacturers reported releases of 16.4 million pounds of toxic chemicals directly into surface water in 1992. However, about 80 percent of the 1992 total was due to an accidental spill of sulfuric and phosphoric acid by one company in Pasadena, Texas.(39) Even discounting the spill, more than 70 percent of toxic water releases occurred in Harris and Jefferson counties, where petrochemical and refining industries are concentrated, and ten companies were responsible for 72 percent of these direct discharges to surface water. Largely because of the spill, Texas ranked second in the country in releases of toxics to surface water in 1992.(40) In 1993, Texas facilities only released 2.3 million pounds of toxics into Texas streams and rivers.(41)
In 1992, more than 32 million pounds of toxic chemicals were transferred to public sewage plants, causing Texas to rank second among the states in the amount of toxics released through sewage plants.(42) Almost 60 percent of these chemicals were produced by three companies in Pasadena, in the Houston/Bay Port region. Harris County was the site of about 80 percent of all toxics transferred to public sewers in 1992. In 1993, toxics transferred to public sewers declined to 22.5 million pounds.(43)
|TOP 10 FACILITIES RANKED BY TOTAL WATER RELEASES IN 1993 AND BY CORRESPONDING WATER RELEASES IN 1992|
|TOTAL RELEASES IN LBS|
|1||Dow Chemical Company||Freeport||Brazoria||277,332||457,265|
|2||Exxon Baytown Refinery||Baytown||Harris||251,704||293,220|
|3||Amoco Oil Company||Texas City||Galveston||227,374||296,030|
|4||Mobil Mining and Minerals Company||Pasadena||Harris||140,000||13,970,810|
|5||Star Enterprises||Port Arthur||Jefferson||121,739||342,391|
|7||Neches River Treatment Corp.||Beaumont||Jefferson||71,657||78,972|
|8||Gulf Chemical and Metallurgical||Freeport||Brazoria||68,365||56,712|
|10||Exxon Chemical Americas||Baytown||Harris||61,753||61,978|
Note: More than 13 million pounds of Mobil Mining and Minerals Company's toxic water releases in 1992 were due to an accidental spill of sulfuric and phosphoric acids.
|TOP 10 FACILITIES RANKED BY TOTAL TRANSFERS TO PUBLICLY OWNED TREATMENT WORKS IN 1993 AND CORRESPONDING TRANSFERS IN 1992|
|TOTAL TRANSFERS IN LBS|
|1||Simpson Pasadena Paper Company||Pasadena||Harris||8,811,930||9,897,000|
|2||Arco Chemical Company||Pasadena||Harris||2,230,000||3,830,710|
|3||Air Products, Inc.||Pasadena||Harris||1,883,770||5,091,600|
|4||Rohm & Haas Bayport||La Porte||Harris||1,137,734||1,199,402|
|6||Union Carbide Corp.||Texas City||Galveston||860,079||796,608|
|8||Dixie Chemical Company||Pasadena||Harris||591,200||586,750|
|9||Akzo Chemicals, Inc.||Pasadena||Harris||570,249||384,530|
|10||Crown Central Petroleum||Pasadena||Harris||499,655||567,182|
Source: Toxics Release Inventory Program, Office of Pollution Prevention and Recycling, Texas Natural Resource Conservation Commission
Facilities that discharge wastewater directly into surface waters are required to submit to the state monthly effluent reports which show whether or not they meet their permit limits. In 1993, 766 industrial facilities and 1,873 municipalities were required to submit monthly effluent reports.(44) In addition to these effluent reports, large municipalities and industries whose permits contain numerical limits on toxics are required to perform total toxicity testing, or biomonitoring, to determine whether their effluent is adversely affecting aquatic life. If biomonitoring reports - and two retests - show the effluent to be lethal to certain species, municipalities and industries must perform what's known as a TRE, or Toxicity Reduction Evaluation, to identify which toxics are affecting the species and adopt a plan to reduce the toxicity of their effluent. For example, there are currently 36 municipalities and 33 industrial facilities which have been required by the Texas Natural Resource Conservation Commission to reduce the toxicity of their effluent because of its lethality to species.(45)
Where self-reports or inspections show violations, the Texas Natural Resource Conservation Commission may begin enforcement action against a permittee. A municipal or industrial discharger must be non-compliant for four months for enforcement actions to be automatically undertaken. Besides these self-reporting requirements, permittees are subject to compliance inspections by the Texas Natural Resource Conservation Commission's 65 wastewater inspectors.(46) These inspectors conduct annual inspections on a selected number of facilities. Due to cuts in funding for inspections, the number of facilities inspected has decreased, even as the number of violations or deficiencies, as determined by inspections and review of self-reporting data, has increased.(47)
Between 1990 and 1993, the Texas Natural Resource Conservation Commission issued 253 enforcement orders with penalties for municipal and industrial wastewater discharge and water quality violations. These orders increased from 45 in 1990 to 75 in 1993.(48)
NUMBER OF ANNUAL COMPLIANCE INSPECTION |
AND PERMIT COMPLIANCE OF WASTEWATER PLANTS IN TEXAS
|INSPECTIONS||ACTIVE PERMITS||% INSPECTED|
|NO. WITH VDF||% NON-COMPLIANT||% COMPLIANT|
Active Permits: Permitted Wastewater Treatment Plants in Active Operation.
VDF: Violations/substantial deficiencies.
Source: Texas Natural Resource Conservation Commission, State of Texas Water Quality Inventory, 12th Edition (Austin: TNRCC, 1995), 256.
While the treatment and discharge of most wastewater in Texas is managed through the permit system, some effluent is discharged into surface waters without treatment. In 1995, the state identified some 340,000 Texans living in unincorporated communities or colonias along the U.S.-Mexican border who had inadequate wastewater treatment facilities.(49) These Texans use improperly operated septic tanks, outhouses, privies or no treatment at all before discharging their wastewater into surface water or into the ground. This practice affects the quality of both groundwater and surface water.
The Rio Grande, the river which forms part of the border between Texas and Mexico, serves as both the major source of drinking water and the principle recipient of wastewater for the region. Water quality for many segments of the Rio Grande has been severely degraded over the years, in part because of the discharging of untreated or partially treated wastewater by Mexican cities. Together, the Mexican border cities of Ciudad Juarez, Ojinaga, Ciudad Acuntilde;a, Piedras Negras, Nuevo Laredo, Reynosa and Matamoros discharge an estimated 175 million gallons of wastewater into the Rio Grande and Gulf of Mexico per day. About 112 million gallons per day is untreated. The remaining 63 million gallons receive only primary treatment, which means that solids and sludge have been removed but no chlorination or other chemical or biological treatment of the wastewater has occurred.(52) In 1993 the U.S. and Mexican governments began construction of a joint wastewater treatment facility for Nuevo Laredo that should be completed in 1995. Similar international wastewater treatment plants are being planned for other border cities.
Source: Texas Extension Educational Service, Texas A & M University System, Basic Wastewater Operations (College Station: Texas Engineering Extention Service, 1994), 3-5.
|HOW IS WASTEWATER PROCESSED?|
|Wastewater can undergo several levels of treatment, each of which makes the water progressively cleaner. The first level, called primary treatment, removes solids, usually by mechanical means. During secondary treatment water is aerated and microorganisms are used to remove remaining small particles. The water is then chlorinated. Tertiary treatment removes nitrates and phosphates before chlorination.
Under federal law, publicly-owned treament works (POTWs) are required to treat wastewater to secondary treatment levels or better. In Texas, about 67 percent of domestic wastewater now receives advanced (tertiary) treatment before discharge. In 1972, that figure was less than 15 percent.(50)
Due to the high construction and operating costs of conventional systems, however, many smaller communities have begun looking into so-called innovative and alternative wastewater treatment plants.(51) Alternative collection systems often use smaller diameter pipes that follow the topography of the land to reduce excavation costs and take advantage of gravity flows. Innovative treatment systems may also utilize natural processes to reduce effluent contaminants to acceptable levels. These processes include using the wastewater to irrigate land, which uses the soil's biological activity to treat it. Or the system may rely on specially constructed wetlands, which physically filter the water and break down contaminants through biological and microbial activity.
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