Chapter 6 – State of the Bay, Third Edition

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CHAPTER 6 – STATE OF THE BAY, THIRD EDITION

Water and Sediment Quality

Written & Revised by Lisa A. Gonzalez

The wondrous nature of water, that it is at once the “universal solvent” and the global transport system for molecules and masses of debris alike, also makes it particularly vulnerable to debilitating, sometimes lethal, contamination. —Sylvia A. Earle in Sea Change: A Message of the Oceans (1995)

Introduction Water pollution in the Houston-Galveston region first became a public concern in the early 1900s with the recognition that sewage contributed pathogenic bacteria to area waterways. In the 1920s, oil pollution in the Houston Ship Channel prompted local and state officials to voice concerns about industrial contamination (Melosi et al. 2007). In 1967, federal investigators identified the Houston Ship Channel as “the worst example of water pollution … observed in Texas” (Melosi and Pratt 2007). This prompted the Texas Water Quality Board (now the Texas Commission on Environmental Quality, TCEQ) to initiate corrective measures to improve the water quality of the Houston Ship Channel and Galveston Bay even prior to the passage of the Clean Water Act in 1972. The portion of the Houston Ship Channel above Morgan's Point (near La Porte) was later listed among the 10 most polluted water bodies in the United States by the U.S. Environmental Protection Agency (EPA). Stringent discharge goals were established in 1971 for industrial and municipal point

sources along Buffalo Bayou and the Houston Ship Channel. All industries discharging to the Houston Ship Channel were required to upgrade their wastewater treatment facilities. Municipal waste treatment facilities discharging to the State of the Bay 2009 Bay the of State

– tributaries of Galveston Bay were enhanced and expanded. Ten years later, the EPA recognized that several Texas waterways

CHAPTER 1 were getting cleaner and singled out the

State of the Bay Houston Ship Channel as "the most notable

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6 improvement, a truly remarkable feat" Figure 6.1. The Houston Ship Channel as seen from the (EPA 1980). top of the San Jacinto Monument. Image courtesy Lisa Gonzalez. CHAPTER

For the most part Galveston Bay has been able to maintain good water quality because it is shallow, well-mixed, and well-aerated. The vast majority of water quality problems are concentrated in the western, urban tributaries of the bay where municipal and industrial development is most pronounced. This chapter deals with the historical trends and the present status of water and sediment quality in the bay. Contributions from point and nonpoint sources are discussed. Biological monitoring of contaminants is included since some chemicals can only be detected after they accumulate in organisms living in the Figure 6.2. Galveston Bay segmentation scheme. Modified from (Jones and Neuse 1992; Ward et al. 1992). water or sediment. Indicators of water and sediment quality along with time-series trend graphs will be used to characterize the large-scale spatial and temporal patterns of water and sediment quality parameters in the Galveston Bay system. The indicators were initially developed by the Galveston Bay Indicators Project (Lester et al. 2005) and were updated in 2009 by the Galveston Bay Status and Trends Project. Temporal trends were statistically analyzed using linear regression analyses on data grouped spatially by tributary or subbay. 2

Trends are classified as significant if the coefficient of determination (R ) is greater than 0.25 and for each State of the Bay

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year at least 10 samples were collected. Positive and negative trends of parameters indicative of the health 6 of the bay are highlighted in this report. Parameters that exhibit no trend are largely omitted.

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The indicators and trend graphs presented in this chapter utilize quality assured, long-term monitoring data collected and managed by various state agencies including the TCEQ, Texas Department of State Health Services (TDSHS), and the Texas Parks and Wildlife Department

(TPWD). When available, data are combined from Figure 6.3. Bolivar Roads is the entrance to the Houston Ship Channel multiple agencies (e.g., and Galveston Bay and is a major inlet to the bay from the Gulf of data describing water Mexico. Image ©2011 Jarrett Woodrow. temperature is collected by the TCEQ and TPWD). For most water quality parameters, the data record extends back at least 35 years. Data analyses end with the 2009 data year. Spatial variation throughout the Galveston Bay system is addressed by aggregating the data into subregions of the bay (e.g., subbays and tributaries). This is done using a hydrographic segmentation scheme originally developed by Jones and Neuse (1992) and Ward and Armstrong (1992) and later modified by the Galveston Bay Status and Trends Project (Lester et al. 2003) (see Figure 6.2).

Water Quality

Temperature

In the context of water quality, water temperature often determines the rates of many chemical reactions and physical processes. For example, the degradation of organic pollutants occurs faster at higher temperatures, if all other reaction conditions are constant. The solubility of oxygen in water decreases as temperature increases. Additionally, the survival of aquatic organisms is affected by temperature. The incidence of pathogens and parasites such as Vibrio vulnificus (Oliver 2005) and Dermo (Perkinsus marinus) State of the Bay 2009 Bay the of State

– (see Chapter 7) are dependent on water temperatures; their populations increase as water temperatures rise. Shallow depths, and mixing by wind, produce water temperatures that are homogeneous with little vertical CHAPTER 1 stratification. The principal source of variation in temperature is seasonal change, as shown in Figure 6.4. As State of the Bay one would expect, average water temperature is highest in the summer months (June, July, and August) at –

6 nearly 30˚Celsius, and lowest in the winter months (December, January, and February) at approximately 14˚C. CHAPTER

Figure 6.4. Average seasonal surface water temperature (≤ 1meter); Galveston Bay 1970–2009; all stations. Diamonds and values represent the average (mean). Error bars represent standard error from the mean. Light blue bars depict the number of samples. Data sources: (TPWD 2008; TCEQ 2009; HGAC 2010).

The TPWD has documented a rising trend in winter water temperatures in all of the Texas bays south of Galveston Bay (Tolan et al. 2009). Similar trends in the water temperatures of Galveston Bay have not yet been observed. As seen in Figure 6.5, there is no trend in surface (≤ 1 meter in depth) or bottom (> 1 meter in depth) water temperatures from 1970–2009. In the graph, bars represent the number of samples collected each year. The trend line represents the trend in annual average temperature for all samples collected in that year. Trends are significant if R2 is greater than 0.25. Water temperatures in localized areas of the bay can be altered by human actions. Effluents with elevated temperatures are discharged from many industrial facilities that use pass-through cooling water. Elevated water temperatures at discharge sites has been shown to change the composition of the ecosystem in the vicinity of the discharge (Jones et al. 1996), but the effect is localized. State of the Bay

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Figure 6.5. Average annual surface water temperature (all depths); Galveston Bay 1970–2009, all stations. Bars represent the number of samples collected each year. The trend line represents the trend in annual average temperature for all samples collected in that year. Trends are significant if R2 is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010; TPWD 2010)().

pH is a measure of the concentration of hydrogen (H+) ions and describes the acidity or alkalinity of a substance. A substance with a pH of 7 is considered neutral; pH < 7 is acidic and pH > 7 is alkaline. pH is measured on a negative logarithmic scale, meaning a pH of 6 is 10 times more acidic than a pH of 7, and 100 times more acidic than a pH of 8. In water, various dissolved compounds, including salts and gases, can State of the Bay 2009 Bay the of State

– affect pH. pH determines, in part, the reactivity of water with various pollutants and therefore the toxicity of those pollutants. Seawater has a higher pH than freshwater due to the concentration of bicarbonate ions in CHAPTER 1 seawater. Therefore, pollutants will react differently in seawater as compared to freshwater. It is also State of the Bay

– interesting to note that photosynthetic organisms can affect pH during respiration; carbon dioxide expelled

6 during hours of darkness can lower pH at night and in the early morning.

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The pH of water is critical to the survival of most aquatic plants and animals. Many aquatic species have trouble surviving if the pH levels drop below 5.0 (too acidic) or rise above 9.0 (too alkaline). For example, acidic precipitation in the upper freshwater reaches of an estuary can diminish the survival rate of eggs deposited by spawning fish (EPA 2006). Although pH generally exhibits low variability in coastal environments due to the high buffering capacity of seawater, human activities can cause significant, short-term fluctuations in pH or long-term acidification of a freshwater body. For instance, algal blooms initiated by an overload of nutrients cause pH to fluctuate dramatically over a period of several hours, greatly stressing local organisms. pH data collected by the TCEQ in the Lower Galveston Bay watershed from 1973 through 2009 were analyzed (39,044 records). pH is not collected by the TPWD Coastal Fisheries Division and was therefore not available. Samples collected at all depths and times were analyzed. An analysis of all samples from tributaries collected at all depths yielded no annual average trend in pH. However, plotting all samples collected from subbays at all depths revealed a declining trend (R2 > 0.25; Figure 6.6). A review of pH in specific water bodies found declining trends in the following subbays and tributaries of Galveston Bay: East Bay, Trinity Bay, West Bay, Chocolate Bay–Bayou, and Dickinson Bay– Bayou. Surface samples collected over the entire watershed yielded no overall trend for Galveston Bay. However, declining trends in surface pH were seen individually for Chocolate Bay–Bayou and Dickinson Bay–Bayou. Declining trends in surface pH were also seen for subbays of Galveston Bay, specifically for East Bay, Trinity Bay, Upper and Lower Galveston Bay, and West Bay. The average pH of Galveston Bay and its tributaries is approximately 7.8. The reason for the declines in pH mentioned above is unknown at this time. Results of a Spearman rank correlation analyses by the Galveston Bay Status and Trends Project yielded no correlation of pH with salinity or water temperature. There appears, however, to be a slight negative relationship between pH and ammonia (r = -.23; p < 0.05) and a slight positive relationship with the concentration of chlorophyll a (r = .22; p < 0.05).

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Figure 6.6. Average annual pH in the subbays of Galveston Bay 1973–2009, all depths. Bars represent the number of samples collected each year. The trend line represents the trend in annual average pH for all

samples collected in that year. Trends are significant if R2 is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010)

Dissolved Oxygen

Dissolved oxygen is one of the most important factors controlling the well-being of estuarine species. Of all State of the Bay 2009 Bay the of State

the parameters that characterize an estuary, the level of oxygen in the water is one of the best indicators of – the estuary’s health (EPA 2006). Few species (such as some single-celled organisms such as blue-green algae and bacteria) can live without oxygen (Begon et al. 2006).

CHAPTER 1 Important factors controlling dissolved oxygen include water temperature, salinity, wind, water

State of the Bay turbulence, atmospheric pressure, the presence of oxygen-demanding compounds and organisms in the

– water, and photosynthesis. The relationship between water temperature and dissolved oxygen is inverse, 6 meaning that as temperature rises, dissolved-oxygen levels fall. The most significant factors influencing dissolved oxygen concentrations in water are turbulence and photosynthesis. Dissolved oxygen is intro-

CHAPTER duced into the water column principally through simple mechanical agitation by wind. In shallow systems

such as Galveston Bay, with small tidal amplitudes (less than 0.4 m), wind-induced mixing is critically important in controlling dissolved-oxygen levels. Plants (such as algae) and photosynthetic bacteria introduce oxygen into the water column as a by-product of photosynthesis. Oxygen availability to aquatic organisms is complicated by the fact that its solubility in water is generally low (EPA 2006). According to the EPA (2006), most aquatic organisms optimally grow and reproduce when dissolved-oxygen levels exceed 5 milligrams per liter (mg/L). When dissolved-oxygen levels drop to 3–5 mg/L, living organisms often become stressed. If levels fall below 3 mg/L, a condition known as hypoxia will occur, causing most mobile species to move elsewhere and resulting in the death of many immobile species. Some species have adapted to low oxygen conditions (for example, by gulping air at the water surface) and continue to exist in hypoxic conditions. Another condition known as anoxia, occurs when the water becomes totally depleted of oxygen (below 0.5 mg/L) resulting in the death of any organism that requires oxygen for survival. Conversely, too much dissolved oxygen is not always beneficial. Supersaturation (dissolved-oxygen levels above 10 mg/L) is often a sign of eutrophication, or over- enrichment, of a water body. Supersaturation can also occur in areas of great turbulence, such as spillways. Algal blooms typically occur in high-nutrient waters. As the algae die, bacterial decomposers consume oxygen, reducing dissolved oxygen to levels too low to support many fish and other aquatic animals (Figure 6.7). Low dissolved oxygen is a common cause of fish kills in the Galveston Bay system. As the fish die, their remains become more

food for the bacteria, expanding State of the Bay

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the low-oxygen area and killing a Figure 6.7. Physical, chemical, and biological processes that 6 larger population of aquatic affect dissolved oxygen concentrations in estuaries (EPA 2006). organisms. CHAPTER

Low dissolved-oxygen levels in the Lower Galveston Bay watershed can result from pollution, poor mixing and flushing, and periodic storms. Low dissolved-oxygen concentrations were a common symptom of high levels of pollution in the Houston Ship Channel prior to discharge permits. The Ship Channel and other portions of the bay exhibited impaired water quality and depressed dissolved-oxygen levels that decreased the abundance of aquatic life. Residential community canals commonly exhibit hypoxic conditions (especially in summer months) due to the lack of circulation in the canals. These canals are hot spots for fish kills (Thronson et al. 2008). In 2008, Hurricane Ike resulted in approximately 200 fish kills in the tidal streams and rivers along the upper Texas Gulf Coast due to the sudden influx of high organic loads from land inundated by the storm surge (FEMA 2008). It is not simple to analyze the record of dissolved oxygen collected from the bay and its tributaries. Concentrations of oxygen vary over a daily cycle as a result of complex interaction of the factors that produce and consume dissolved oxygen in surface waters. The photosynthetic organisms in water are dependent on light for the energy to drive photosynthesis. Thus, during daylight of suitable intensity these organisms release oxygen to the water and raise the dissolved-oxygen concentration, sometimes above chemical-saturation levels. At night, photosynthetic organisms require oxygen for respiration and remove it from the water. To account for the differences in dissolved oxygen at various times of the day, the analysis presented here considers only those samples collected between 5 and 10 a.m. Limiting the time of collection allows resulting trends to be attributed to factors other than the effects of time of day, amount of sunlight, or resulting water temperature. Data on dissolved oxygen were obtained from the TCEQ Surface Water Quality Monitoring Program, other programs of the TCEQ such as the Texas Clean Rivers Program which is administered locally by the Houston-Galveston Area Council (HGAC) and the TPWD Coastal Fisheries Division. Dissolved-oxygen concentrations in Galveston Bay have been sampled since 1969; however, the trends below span 1979– 2009. Data collected between 1969 and 1978 were omitted from the trend analysis because fewer than 10 samples per year were collected from some subbays and tributaries.

An analysis of all samples (from tributaries and subbays) collected at all depths yielded no annual average trend in dissolved oxygen. There was also no overall trend for tributaries. However, a review of all samples collected from subbays at all depths revealed a declining trend (R2 = 0.66; Figure 6.8). A review of dissolved oxygen in specific water bodies at all depths found declining trends in all 5 subbays of Galveston Bay (see the declining trend for Trinity Bay in Figure 6.9), as well as Chocolate and Dickinson Bayous. State of the Bay 2009 Bay the of State While the declining trends in dissolved oxygen may be cause for concern, on average dissolved-oxygen – levels appear healthy and remain well above 5 mg/L.

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Figure 6.8. Average annual dissolved oxygen in the subbays of Galveston Bay 1976–2009; all depths; samples collected between 5 and 10 a.m. Bars represent the number of samples collected each year. The trend line represents the trend in annual average dissolved oxygen for all samples collected in that year. Trends are significant if R2 is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010; TPWD 2010) State of the Bay

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Figure 6.9. Average annual dissolved oxygen in Trinity Bay 1976–2009; all depths; samples collected between 5

and 10 a.m. Bars represent the number of samples collected each year. The trend line represents the trend in annual average dissolved oxygen for all samples collected in that year. Trends are significant if R2 is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010; TPWD 2010)

Salinity State of the Bay 2009 Bay the of State

– Salinity is a measure of the amount of salts dissolved in water. Galveston Bay exhibits a salinity gradient along its length, as freshwater entering the estuary from tributaries (rivers and bayous) mixes with seawater moving in from the Gulf of Mexico. Salinity, along with water temperature, is the primary factor in

CHAPTER 1 determining stratification (i.e., the formation of layers that act as barriers to water mixing). When fresh and State of the Bay saltwater meet, the two do not readily mix. Just as warm water is less dense than cold water, freshwater is –

6 less dense than saltwater and will lie on top of the wedge of seawater pushing in from the ocean. Storms, tides, and wind, however, can thoroughly mix the water and eliminate the layering caused by salinity and temperature differences. CHAPTER

Salinity levels influence the community composition of plants and animals that live in different areas of the estuary. As an example, West Bay typically has higher salinities than Trinity Bay and one would therefore expect to see different species assemblages in the 2 subbays. Salinity affects the extent to which parasites and diseases infect aquatic organisms such as commercially important Eastern oysters (Crassostrea virginica). It is for these reasons that freshwater inflow to bays and estuaries is such a large issue in coastal areas. Salinity has been monitored in the Galveston Bay system by the TCEQ since 1973. However, the bulk of the data were collected since the late 1980s. Therefore, trends span 1987–2009. Salinity is reported in practical salinity units (psu). Salinity data collected by the TPWD Coastal Fisheries Division were quality- assured and combined with the TCEQ data to increase spatial and temporal coverage.

Figure 6.10. Average annual salinity in the tributaries of Galveston Bay 1987–2009; all depths. Bars represent the number of samples collected each year. The trend line represents the trend in annual average salinity for all State of the Bay 2 –

samples collected in that year. Trends are significant if R is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010; TPWD 2010)(). 6

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When data from all Galveston Bay stations were analyzed, no temporal trends were found. Additionally, there were no trends in salinity in the subbays of Galveston Bay. However, a declining trend in salinity (R2 = 0.36) was seen in the tributaries of Galveston Bay at all depths (Figure 6.10). When looking at specific tributaries, declining trends were found for Dickinson Bayou–Bay (R2 = 0.32; 1987–2009; samples from all depths), Buffalo Bayou (R2 = 0.57; 1988–2009; all depths), Clear Creek–Clear Lake (R2 = 0.40; 1987– 2009; all depths) and the San Jacinto River (R2 = 0.53; 1988–2009; all depths).

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– Figure 6.11. Average annual salinity in the San Jacinto River, 1988–2009; all depths. Bars represent the number of samples collected each year. The trend line represents the trend in annual average salinity for all samples collected in that year. Trends are significant if R2 is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010; TPWD 2010) CHAPTER 1 While the salinity declines in the bay’s tributaries are of interest, particularly with regards to the larger State of the Bay

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issue of the quantity of freshwater inflows reaching the bay, it must be noted that salinity is greatly 6 influenced by the amount and timing of rainfall relative to the time of sampling. The quantity and timing of precipitation can potentially bias salinity measurements in these water bodies. However, the fluctuations CHAPTER

around the trend lines shown in Figure 6.10 and Figure 6.11 track reasonably well the total freshwater inflows modeled by the Texas Water Development Board (TWDB) through 2005 (TWDB 2010).

Nutrients

Nutrients such as nitrogen and phosphorus are chemical elements or compounds essential for plant and animal survival and growth. Nutrients are used by both plants and animals in numerous metabolic processes including protein synthesis and energy transfer. Nutrients enter the estuary from a variety of sources, including tributary inflow, terrestrial runoff, and benthic and atmospheric deposition originating from industrial, point source, and nonpoint sources. Nutrients also enter bay waters from the sediments where bacteria mineralize nutrients from organic material (Zimmerman et al. 1994; Warnken et al. 2000). Byun et al. (2008) estimated atmospheric loading of nitrogen to the Galveston Bay system to be 11 percent of total nitrogen loadings. Total nitrogen loading from atmospheric sources was estimated to be approximately 4,330 tons of nitrogen per year. High amounts of nutrients have been associated with over-fertilization of agricultural land and suburban yards.

Figure 6.12. Sources of nutrients to an estuary. Data source: (EPA 2006).

A nutrient necessary for growth and survival of an organism, but in limited supply relative to the concentration of other nutrients, is known as a limiting nutrient. In estuarine systems (including Galveston State of the Bay

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Bay), nitrogen is generally considered to be the limiting nutrient (Nixon 1981; Day et al. 1989; Zimmerman and Benner 1994). By this definition, increases in nitrogen concentrations (relative to 6 phosphorus) result in greater primary productivity. However, ratios of nitrogen to phosphorus in an estuary

may vary across space and time, given the relative contributions of riverine inflows and oceanic inputs. It is CHAPTER

possible that in estuarine ecosystems such as Galveston Bay, under some conditions, phosphorus is a limiting nutrient (Murrell et al. 2007) or phosphorus and nitrogen may co-limit primary productivity (Juhl et al. 2008). Water quality parameters monitored by state and local agencies to determine nutrient concentrations in surface waters include total phosphorus, ammonia-nitrogen, and nitrate-nitrogen, among others. Analyses by the Galveston Bay Status and Trends Project in 2009–10 compared concentrations of nutrients and chlorophyll a (an algal pigment used as an indicator of phytoplankton abundance and primary productivity) in Galveston Bay surface waters to screening levels established by the TCEQ. Major subbays and tributaries of the bay were rated based on the percentage of samples exceeding TCEQ (2008a) screening limits (Table 6.1) in a given area in a given decade. The methodology was developed in the Galveston Bay Indicators Report (Lester and Gonzalez 2005).

Table 6.1. Selected state water quality criteria used in development of nutrient indicator. Data source: (TCEQ 2008a)

Nutrient Tidal Stream Estuarine Parameter Screening Level Screening Level Dissolved oxygen 2.0 mg/L 2.0 mg/L Total phosphorus 0.66 mg/L 0.21 mg/L Orthophosphate 0.46 mg/L 0.19 mg/L Chlorophyll a 21.0 µg/L 11.6 µg/L Ammonia 0.46 mg/L 0.10 mg/L Nitrate-nitrite 1.10 mg/L 0.17 mg/L

As seen in Figure 6.13, many areas of the bay (15 out of 19 subbays and tributaries) have experienced an improvement in overall nutrient and chlorophyll a concentrations since the 1970s. In the 1970s, 9 out of 19 subbays and tributaries displayed poor water quality with regard to high nutrient concentrations while only State of the Bay 2009 Bay the of State 3 areas rated good or very good. In contrast, data collected between 2000 and 2009 show that no subbays – or tributaries rated poor, while more than half (13 out of 19) are now identified as having good or very good nutrient water quality. This vast improvement in nutrient and chlorophyll a concentrations is largely due to the success of wastewater-permit regulations implemented under the Clean Water Act. CHAPTER 1 State of the Bay

As of 2010, three of the 5 subbays (Christmas Bay, West Bay, and East Bay) are rated good overall. Upper –

6 and Lower Galveston Bay and Trinity Bay continue to be rated as moderate in terms of nutrient and chlorophyll a concentrations.

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Of the 14 tributaries assessed in 2010, 7 rate very good in terms of nutrient and chlorophyll a concentrations. Three bayous (Trinity River, Clear Creek, and Cedar Bayou) rate good for nutrient concentrations. Armand Bayou, Buffalo Bayou, and the Houston Ship Channel rate moderate. No subbays or tributaries rate poor for excessively high nutrients and chlorophyll a.

Figure 6.13. Indicator showing the percentage of nutrient (ammonia, nitrate-nitrite, total phosphorus, orthophosphate) and chlorophyll a or pheophytin a samples exceeding TCEQ (2008a) screening levels, 1970s versus 2000s. Fifteen out of 19 subbays and tributaries have experienced an improvement in overall nutrient and chlorophyll a concentrations since the 1970s. Data sources: (HGAC 2010; TCEQ 2010).

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Total Phosphorus

Phosphorus is an important nutrient, required for synthesis of genetic material. However, it causes eutrophication of freshwater when found in excessive amounts. Phosphorus exists in surface water as organic phosphate, orthophosphate (inorganic, dissolved phosphorus), total phosphorus (dissolved and particulate), and polyphosphate (from detergents) (EPA 2006). Figure 6.14 depicts the movement and cycling of phosphorus compounds in an estuary. Phosphorus enters an estuary naturally through the decomposition of organic materials and anthropogenically through water- treatment plants, untreated sewage discharge, and runoff from animal feedlots, soils, agricultural fields and lawns. High phosphorus loads are often delivered during periods of high runoff from storms or irrigation activities (EPA 2006).

Figure 6.14. The phosphorus cycle in an estuary (EPA 2006).

State of the Bay 2009 Bay the of State

Total phosphorous samples recorded from Galveston Bay range from less than 0.01 mg/L to greater than – 40 mg/L (collected from the Houston Ship Channel in the 1970s). The trend in annual averages of total phosphorus sampled from the bay and its tributaries from 1973 through 2009 is one of decline (Figure 6.15). While overall declines in total phosphorus concentrations occurred in both subbays (R2 = .31) and

CHAPTER 1 tributaries (R2 = .69), the decline is most pronounced in the tributaries to Galveston Bay. As seen in Figure

State of the Bay 2 6.16, the most dramatic decline occurred in the Houston Ship Channel (R = .76). –

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Figure 6.15. The declining trend of total phosphorus in the Galveston Bay estuary, all stations and depths, 1973– 2009. Bars represent the number of samples collected each year. The trend line represents the trend in annual average total phosphorus for all samples collected in that year. Trends are significant if R2 is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010).

Figure 6.16. The declining trend of total phosphorus in the Houston Ship Channel, all stations and depths, 1973– 2009. Bars represent the number of samples collected each year. The trend line represents the trend in annual average total phosphorus for all samples collected in that year. Trends are significant if R2 is greater than 0.25.

Data source: (HGAC State of the Bay

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2010; TCEQ 2010). 6

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Nitrogen

Although nitrogen makes up 78 percent of the earth’s atmosphere, it is inaccessible to most terrestrial and aquatic organisms. Some types of bacteria and blue-green algae, however, can fix nitrogen gas, making it available to other organisms (Begon et al. 2006; EPA 2006). In the Galveston Bay estuary, nitrogen cycles through the system in a variety of chemical forms (e.g., ammonium, ammonia, nitrite, and nitrate—see Figure 6.17). As with phosphorus, nitrogen can enter the estuary through numerous sources (see Figure 6.12). The quantity and form of nitrogen in the water are closely related to dissolved-oxygen levels. When nitrification (i.e., the conversion of ammonium ions to nitrate) is inhibited by low dissolved oxygen, ammonia or nitrite forms of nitrogen may accumulate (EPA 2006). Ammonia is toxic at high concentrations and contributes to elevated (alkaline) pH. High ammonia concentrations are also observed in waters that are hypoxic or anoxic for significant periods of the year. Nitrate is a nutrient that can be readily used by plants, and is important for the production of phytoplankton (a major base of the food web) in Galveston Bay. Nitrate is also typically the greatest nutrient component of commercial fertilizers.

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– Figure 6.17. The nitrogen cycle in an estuary (EPA 2006).

There is no trend in nitrate-nitrite concentrations in Galveston Bay or any of its subbays or tributaries for the period of record, 1973 to 2009. In contrast, the general trend of ammonia concentrations in Galveston CHAPTER 1 Bay and its tributaries is one of decline (Figure 6.18). There is no overall trend in ammonia samples State of the Bay

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collected from the subbays of Galveston Bay. However, there is a significant decline in ammonia 6 concentration in the bay’s tributaries (R2 = 0.74) (Figure 6.19). Significant declines in ammonia (R2 > 0.25) are seen specifically in Buffalo Bayou, the Houston Ship Channel, and Clear Creek–Clear Lake. One

CHAPTER subbay, Upper and Lower Galveston Bay, exhibits a declining ammonia trend as well.

Declines in ammonia are largely due to the success of water quality permitting in controlling point source discharges. The remaining sources of nitrogen to the estuary are primarily nonpoint sources—diffuse and difficult to control. Nonpoint sources include yards, roadways, air deposition, and agriculture. As discussed previously, water quality management has succeeded in reducing nutrients in much of the Galveston Bay system, but each nutrient has a different historical pattern with some water quality improvements occurring earlier than others. Over the last 30 years, ammonia concentrations were the first to decline and were succeeded by total phosphorus, and then nitrate-nitrite concentrations. This succession in water quality improvement can be traced to the implementation of point source water quality permitting regulations and the remaining difficulty in controlling nonpoint sources of nutrients.

Figure 6.18. The declining trend of ammonia in the Galveston Bay estuary, all stations and depths, 1973–2009. Bars represent the number of samples collected each year. The trend line represents the trend in annual average ammonia for all samples collected in that year. Trends are significant if State of the Bay 2 –

R is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010). 6 CHAPTER

Figure 6.19. The declining trend of ammonia in tributaries of the Galveston Bay, all stations and depths, 1973–2009. Bars represent the number of samples collected each year. The trend line represents the trend in annual average ammonia for all samples collected in that year. Trends are significant if R2 is greater than 0.25. Data sources (HGAC 2010; TCEQ 2010).

Chlorophyll a

Chlorophyll a is a measure of the concentration of the principal photosynthetic pigment in green plants. As such, this parameter is a surrogate indicator of the amount of phytoplankton (single-celled algae) that are present in the water. Phytoplankton are primary producers at the base of the Galveston Bay food web. State of the Bay 2009 Bay the of State

– Through photosynthesis, phytoplankton convert solar energy, carbon dioxide, and water into sugars that can be used by herbivorous animals such as zooplankton, oysters, and some fish; these primary consumers support higher levels of the bay food web (see Chapters 2 and 8).

CHAPTER 1 Chlorophyll a concentrations occasionally reach very high levels in the waters of the bayous and the bay, State of the Bay

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particularly in the spring and summer months. Just as plants in a yard or garden grow more rapidly after 6 fertilizers are applied, when a sufficient amount of nutrients are present in the water, algal blooms can occur. The subsequent die-off and decomposition of a large amount of algae in the water can lead to a

CHAPTER hypoxic (low oxygen) conditions and fish kills. The combination of nutrients, high chlorophyll

concentrations, high water temperatures, and low dissolved oxygen that is frequently observed in Galveston Bay tributaries is thought to be primarily responsible for large fish kills (typically of Gulf menhaden) in the summer months. Data collected by the TCEQ between 1973 and 2009 indicate a slightly declining trend in chlorophyll a concentrations of Galveston Bay (R2 = 0.26; Figure 6.20). This trend is only seen when data from all sampling stations are analyzed. There are no trends, either individual or collective, in chlorophyll a in the subbays or the tributaries to Galveston Bay. Note that, due to water quality sampling and testing procedures of the past, chlorophyll a is analyzed along with pheophytin a, one of its breakdown products. This combination serves as a more accurate indicator of phytoplankton concentrations. As seen in Figure 6.20, after the sharp decline in chlorophyll a concentrations in the 1980s and 1990s, peaks in average chlorophyll a concentrations were seen in the last decade, specifically in 2003, 2005, and 2008. From 2000 to 2009, the greatest number of exceedences of TCEQ screening levels for chlorophyll a and pheophytin a occurred in Upper and Lower Galveston Bay (29 percent of samples), Buffalo Bayou (28 percent of samples), Armand Bayou (23 percent of samples), and the Houston Ship Channel (20 percent of samples). Buffalo Bayou and the Houston Ship Channel have heavily urbanized watersheds that flow directly into Upper Galveston Bay. Armand Bayou is a tributary located in the Clear Creek watershed in southeastern Harris County. This tributary to Upper Galveston Bay is known for frequent and sometimes persistent algal blooms in the warm summer months. High chlorophyll concentrations are also often observed in Dickinson Bayou (Quigg et al. 2009). The low dissolved-oxygen concentrations measured in the water column after an algal bloom are thought to be a primary causal factor in the fish kills observed in that bayou. State of the Bay

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Figure 6.20. The declining trend of chlorophyll a and pheophytin a in the Galveston Bay estuary, all stations and depths, 1973–2009. Bars represent the number of samples collected each year. The trend line represents the trend in annual average chlorophyll a and pheophytin a for all samples 2

collected in that year. Trends are significant if R is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010).

Pathogens

Pathogens in surface waters of the Lower Galveston Bay watershed are one of the most pressing water State of the Bay 2009 Bay the of State

quality issues in the region. Although there has been some improvements since the 1970s (Figure 6.21), a – number of urban and suburban tributaries continue to have elevated bacterial concentrations. High concentrations of pathogenic bacteria and viruses in surface waters of Galveston Bay and its tributaries can adversely affect human health through various activities—including consumption of raw shellfish and

CHAPTER 1 ingestion of water during contact recreation. These topics are discussed in Chapter 9. The discussion below State of the Bay focuses primarily on monitoring bacterial pathogens and spatial and temporal trends. –

6 Because it is difficult to test waters for the presence of viruses or other actual pathogens, three indicators of bacterial pathogens—fecal coliform bacteria, E. coli in freshwater, and Enterococci in saltwater—are used in CHAPTER

water quality monitoring. The presence of these bacterial indicators suggests that potentially dangerous pathogens could be present in local surface waters. Water quality sampling in surface waters of Galveston Bay and its tributaries is conducted by the TCEQ and the TDSHS Bacteriological Monitoring Program. Many of the TCEQ sampling stations used to assess bacteria concentrations are located in urbanized tributaries of the bay. Stations monitored by the TDSHS tend to be located in the open bay near oyster harvest areas. High bacterial concentrations are typically associated with slow-flowing bayous in summer months when storm waters carry high bacterial loads from soils and bacterial survival in sediments is favored by high temperatures and high nutrient levels. As a result, water samples taken from open bay waters show substantially lower bacteria concentrations than do the tributaries. However, recent studies suggest that estuarine sediments are capable of maintaining high levels of persistent indicator bacteria that can be resuspended in the water column (Hartel et al. 2007; Fries et al. 2008). Bacterial and viral survival increases with attachment to sediment particles. Thus, there is uncertainty in the relationship between nonpoint source loadings of bacteria in storm water and measured concentrations in the water of the Galveston Bay system. Analyses by the Galveston Bay Status and Trends Project during 2009–10 compared concentrations of fecal coliform indicator bacteria in Galveston Bay surface waters to screening levels established by the TCEQ (2008a) (Table 6.2). Major subbays and tributaries of the bay were rated based on the percentage of samples exceeding TCEQ screening limits in a given area and given decade. The methodology was initially developed by the Galveston Bay Indicators Project (Lester and Gonzalez 2005).

Table 6.2. Selected state water quality criteria used in development of the pathogen indicator. Data source: (TCEQ 2008a). Pathogen Freshwater Saltwater Parameter Screening Level Screening Level Fecal coliform 400 colonies/100 mL 400 colonies/100 mL E. coli 394 MPN*/100 mL Not applicable Enterococci Not applicable 89 MPN/100 mL

* Most probable number

As seen in Figure 6.21, of the 19 major subbays and tributaries assessed, 9 rate as good in terms of indicator bacteria concentrations. This includes all 5 subbays and 4 tributaries located on the west and east sides of the bay. Five Galveston Bay tributaries currently rate poor for bacterial contamination: Buffalo Bayou, Clear Creek, Armand Bayou, Dickinson Bayou–Bay, and Cedar Bayou. Of the 5 tributaries, Buffalo Bayou has the poorest water quality in terms of bacterial indicators. In the 1970s, 99 percent of samples from Buffalo Bayou exceeded TCEQ screening levels and in the most recent decade, 83 percent of bacteria State of the Bay

– samples from Buffalo Bayou exceeded TCEQ screening levels. Five bay tributaries currently rate moderate 6 for pathogen contamination. They are Bastrop Bayou, Chocolate Bayou–Bay, Oyster Bayou, the Houston Ship Channel (with 23 percent of samples exceeding water quality screening levels) and the San Jacinto

River. CHAPTER 24

Figure 6.21 compares the percentage of samples exceeding TCEQ bacteria screening levels in the 1970s to the most recent decade (2000–09). Of the 19 subbays and tributaries assessed, a majority (13) have remained the same. Four tributaries have improved (Bastrop Bayou, Galveston Channel, the Houston Ship Channel, and the Trinity River). Most notable, the Houston Ship Channel has shown a gradual improvement over the last 30 years, with 57 percent of samples exceeding screening levels in the 1970s, 48 percent in the 1980s, 37 percent in the 1990s, and 23 percent in the most recent decade. Two tributaries have degraded in terms of bacterial concentrations since the 1970s: Chocolate Bayou (good to moderate) and Dickinson Bayou (moderate to poor). The vast majority of bacterial water quality problems occur in the tributaries flowing into Upper and Lower Galveston Bay (Figure 6.21). The watersheds of these tributaries are heavily urbanized and often have aging sewerage (e.g. Buffalo Bayou) or are situated in rapidly urbanizing watersheds (e.g. Dickinson, Clear Creek and Armand bayous).

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– CHAPTER 1

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6 Figure 6.21. Indicator describing the percentage of pathogen (fecal coliform bacteria, E. coli, and Enterococci) samples exceeding TCEQ screening levels, 1970s versus 2000s. Data sources: (HGAC 2010; TCEQ 2010; TDSHS 2010).

CHAPTER

The presence of elevated bacteria levels in many of the bay’s western, urban tributaries prompted the designation of 7 projects related to bacteria total maximum daily loads (TMDLs) in the Houston- Galveston area. TMDLs often require additional monitoring and modeling efforts to determine the sources of pollutants and amount of pollutant loadings to the water body of interest. TMDL projects bring together agency personnel, area stakeholders, and water quality experts to formulate an implementation plan (I- Plan) that will lower loadings and remedy high levels of bacteria in the waterway of interest. Because of the large geographic extent of the bacterial water quality problems in the Houston- Figure 6.22. Map of impaired surface waters of the Lower Galveston Bay watershed. Data source: (TCEQ 2008b). Galveston region, a group of diverse stakeholders was convened by the Houston-Galveston Area Council. The Bacteria Implementation Group is responsible for receiving input, establishing workgroups, facilitating communications, developing recommendations, and overseeing the development of an I-Plan for 4 area TMDLs (HGAC 2009). Figure 6.22 depicts the water bodies of the Lower Galveston Bay watershed that are listed as impaired on State of the Bay

the Texas 303(d) List (TCEQ 2008b). Nearly 96 percent of the stream miles in Harris County are listed as –

impaired, along with approximately 69 percent of the stream miles in Galveston County (Gonzalez et al. 6 2008).

CHAPTER 26

As mentioned previously, although bacterial contamination of area waterways is recognized by many as the greatest water quality concern in the Lower Galveston Bay watershed at present, a review of historical data collected by the TCEQ and the TDSHS since 1973 shows overall improvements in the bacterial concentrations of tributaries to Galveston Bay (Figure 6.23). Data collected in the subbays show no trend through time, but do exhibit considerably lower bacterial concentrations when compared to the tributaries (note the y-axes of Figure 6.23 and Figure 6.24).

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– Figure 6.23. Annual average fecal coliform in the tributaries of Galveston Bay, all stations and depths, 1973–2009. Bars represent the number of samples collected each year. The trend line represents the trend in annual average fecal coliform for all samples collected in that year. Trends are significant if R2 is greater than 0.25. Data sources: (HGAC 2010; TCEQ 2010; TDSHS 2010). CHAPTER 1 State of the Bay

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6 CHAPTER

Figure 6.24. Annual average fecal coliform and Enterococci in the subbays of Galveston Bay, all stations and depths, 1973–2009. Values of fecal coliform and Enterococci are averaged together. Bars represent the number of samples collected each year. The trend line represents the trend in annual average fecal coliform and Enterococci for all samples collected in that year. Trends are significant if R2 is greater than 0.25. Data sources: (TCEQ 2009; HGAC 2010; TCEQ 2010; TDSHS 2010). State of the Bay

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6 CHAPTER

Bacteria in the Bayous By Lisa A. Gonzalez

Houston is often called the “Bayou City” because it has developed around a network of these placid water bodies (Figure 6.25). Bayous are old channels carved by rivers that then migrated elsewhere. The Trinity, San Jacinto and Brazos Rivers have all left these features on the landscape of the Lower Galveston Bay watershed. When the rivers moved, some bayous were left without a permanent source of water apart from the bay (through tidal influences). Others were fed by springs that later stopped flowing as groundwater sources diminished. Today most of Houston’s bayous are fed by rainfall, runoff, and discharges from wastewater-treatment plants. They exhibit very low flow rates between rain events and are tidally influenced over much of their length. Because of these characteristics, bayous do not exhibit the same water quality characteristics as flowing, non-tidal streams. It is believed that Houston’s bayous were used historically for swimming and fishing, and they are treated accordingly in water quality assessments. However, it is difficult to find documentation of continuing use of all bayous for contact recreation and fishing. Questions have been raised about the appropriateness of watershed plans that would limit the loading of pollutants to attain a use that is no longer relevant and may not be attainable. Would cleaner water encourage swimming in the concrete lined sections of Bray’s Bayou? Is this a desired goal? Use-attainability studies (EPA 2008), which evaluate applicability of historical waterway uses, are currently in progress for a number of urban bayous. Information on use of urban bayous for contact recreation or fishing should be sent to the TCEQ or the Houston-Galveston Area Council. The greatest challenge to the attainment of water quality standards and historical uses for urban bayous in the Lower Galveston Bay watershed is the concentration of bacteria. In the early 1970s the concentrations measured in Galveston Bay’s tributaries were very high (see Figure 6.23 and Figure 6.24). Over the years, the concentration of fecal coliform bacteria, an indicator of pollution by human and animal waste, has declined dramatically. However, this indicator still often exceeds the criteria used to determine whether a water body is safe for contact recreation (Petersen et al. 2006). High bacterial concentrations can lead to a water body being listed as impaired for historical uses. There are 3 issues associated with the decision to declare a bayou impaired: First, is the bacterial indicator appropriate to determine risk to humans? Second, is the criterion level set at a value appropriate for bayous? Third, is contact recreation an appropriate use for this water body today? The fecal-coliform test, traditionally used as an indicator, commonly gives false positives and has been replaced by the TCEQ with E. coli testing in fresh water. Despite increased accuracy of the indicator in estimating human-derived contamination, E. coli are not necessarily derived from human waste. Mammals and birds host bacteria that are detected by E. coli testing. The Houston area has substantial populations of State of the Bay dogs, cats, birds and wildlife. –

6 Fast moving streams with high water quality lose their bacterial loads through death of the cells plus deposition and consumption by the benthic community. Coastal waters may contain high concentrations of

CHAPTER coliform bacteria, despite an absence of obvious sources, because their sediments act as a sink and source

(Stewart et al. 2008). It may be characteristic of bayous to maintain a higher level of bacteria than a low nutrient, fast moving stream. A similar distinction has been recognized by creation of a special category of tidal streams for dissolved oxygen standards. The dissolved-oxygen criterion for tidal coastal streams is 1 milligram per liter lower for aquatic-life use than the criterion for inland streams (TCEQ 2008a). However, Tolan (2008) found that, for Texas coastal streams, water quality values indicating impairment based on the established standards did not correlate with impaired diversity or abundance of aquatic life. Further modification of water quality standards may be necessary for these unique coastal water bodies. During the early part of Houston’s history, people engaged in more outdoor activities and had fewer constructed amenities, such as swimming pools. Trends in the built environment and human activity patterns suggest that there is a much lower probability that swimming will take place in bayous today. The actual frequency of contact recreation in bayous should be confirmed. There are many environmental challenges facing the agencies that manage the Galveston Bay watershed. They should be permitted to prioritize problems according to the actual risk to people associated with the issue. If contact recreation is not a current or likely future use, then effort could be directed to higher-priority problems. Bayous are a distinctive aquatic resource for the Galveston Bay watershed, but they must be treated appropriately in the context of water quality and ecosystem services. State of the Bay

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Houston is blessed with an extensive network of bayous. The rich fertile banks are ideal habitats for native plants and wildlife. Migrating birds find the trees along the bayous ideal for resting on their journeys north and south. A few natural bayous remain relatively unspoiled by flood control projects, and these are indeed precious recreational assets that must be preserved. They shout loudly at us by comparison to channelized projects: “What have you done!” These natural bayous are wonderful places to paddle in canoes and kayaks, hike along the banks or just watch the water flow by. On the bayou, trees overhang the water giving shade in the summer. Evaporation cools the air, and gentle breezes cool the body. I used to believe we needed to drive 2 hours or more to find nature. What a discovery it is to find nature right here in our own backyard. As awe-inspiring as they are, our natural bayous are not perfect. For the last 100 years or so, the bayous have collected our sanitary sewage and stormwater run off and carried it off downstream and out of mind. Unfortunately, most of us still think of bayous in this way. To deal with the growing problems of a big city, we turned to our engineers for help. One result is that our urban infrastructure is one of the most efficient in the world; but, the problem with engineering is that it only deals with the given criteria. Habitat, if included at all, is low on the list. A result of past engineering is that most of our bayou habitat is irreparably destroyed, and the few remnants are severely stressed. Then there are bacteria, naturally occurring organisms essential to our ecology. Bacteria are everywhere and generally not a problem. E. coli are specific to human and animal waste. When found in abnormally high levels, it indicates a breakdown in treatment systems and the potential for serious health risks. The City of Houston has done a commendable job over the last 20 years or so, cleaning up sanitary treatment plants. Now, the water coming out of these plants is clear and relatively bacteria free. So why are all of our bayous still impaired? Unfortunately, nobody knows for certain. There are several theories, but little consensus.

Even though the City of Houston is doing a good job treating sanitary sewage, new studies have shown some bacteria living in colonies can survive chlorination. Also, suspended solids in treated effluent can provide food for bacteria already in the stream. Smaller cities and neighborhood treatment plants are not tested as frequently. Problems may go undetected for days before they are corrected. Many residential septic systems are still in use and they are rarely tested. We need to address all of these problems to restore our bayous.

State of the Bay 2009 Bay the of State Once, all our bayous ran crystal clear. I believe they can again, but first we need to change the way we look

– at them. We need to recognize the peace and serenity they offer. We need to value the natural beauty of the wooded habitat along their banks. Then we need to undo much of the damage and restore our bayous to a natural appearance. Houston can never go back to primitive conditions, but we can use nature as a model to

CHAPTER 1 guide future development. State of the Bay

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6 —Bruce Heiberg, AIA, Signal Creek Architects, LL CHAPTER

Sediment Quality

Metals

Under normal conditions, the concentrations of mercury, lead, cadmium, and arsenic in the water is low and often cannot be detected by standard instrumental methods. Thus, metals dissolved in water are not monitored frequently. The most frequently used sampling protocol for metals involves their detection in sediments. Metals may also be found in fish tissue; the results of those monitoring efforts are discussed in Chapter 9. In the 1970s and 1980s, the majority of metals in sediment samples were collected from the tributaries to Galveston Bay, especially the Houston Ship Channel and Clear Creek. That changed in the 1990s as stations in the subbays of Galveston Bay were increasingly monitored. The number of monitoring samples for selected metals (arsenic, cadmium, chromium, copper, lead, mercury, nickel, silver, and zinc) in sediment is now greater in subbays (1,655 samples since 2000) than in the tributaries (1,523 samples since 2000). The increase in subbay sampling reduces the uncertainty associated with drawing conclusions about metal pollution in the bay. We can now state with more certainty that metal pollution is of decreasing concern in Galveston Bay. Analyses by the Galveston Bay Status and Trends Project during 2009–10 compared concentrations of metals in sediment to screening levels established by the TCEQ Ecological Assessment Program (TCEQ 2008a). The TCEQ screening levels replace NOAA probable effect levels (PELs) used in prior Status and Trends assessments. Major subbays and tributaries of the bay were rated based on the percentage of samples exceeding TCEQ screening levels for marine waters in a given subbay or tributary in a given decade. The methodology was initially developed by the Galveston Bay Indicators Project (Lester and Gonzalez 2005). As seen in Figure 6.26, the 5 subbays of Galveston Bay generally rate good or very good in terms of sediment concentrations of metals in the 1970s and very good in the decade since 2000. Warnken et al. (2009) reported that less than 20 percent of the pollutant trace metal load in waters of the Trinity River enters Galveston Bay. The remainder is lost to the sediments of 23 artificial lakes along the river’s course. The most problematic area in terms of the greatest number of metals exceedences in the Lower Galveston Bay watershed has historically been the Houston Ship Channel and even that area has shown improvement. Since 1970, 141 metals exceedences (85 percent of all metals exceedences reported in the subbays and tributaries of Galveston Bay) have been documented in the Houston Ship Channel. In the 1970s the Houston Ship Channel rated moderate (Figure 6.26) with high silver and zinc concentrations. There were also some issues of contamination of sediments by lead and mercury. In the years since 2000, the picture has improved, with the number of cadmium, lead, silver, and zinc exceedences decreasing. Concentrations of State of the Bay mercury (Figure 6.26) remain high in the upper Houston Ship Channel, particularly at locations such as –

Patrick Bayou in Deer Park, which has been listed on the National Priority List as a Superfund site since 6 2002. This is illustrative of the effect pollution hot spots can have on the assessment of conditions in the

bay. CHAPTER

Figure 6.26. Indicator describing 9 metals in sediments of Galveston Bay and the Houston Ship Channel, 1970s and the decade since 2000. Data sources: (HGAC 2010; TCEQ 2010).

Chlorinated Organic Compounds

Contamination of water, sediment, and tissue with chlorinated organic compounds can come from many sources. As discussed previously in this chapter, contamination of surface waters and sediments may come from point sources (identifiable sources at specific locations such as wastewater outfalls) or nonpoint sources (multiple sources located across a relatively large area such as urban runoff). Whereas nonpoint sources are often associated with bacterial contamination and excess nutrient runoff, point sources are typically associated with chlorinated organic compounds such as polychlorinated biphenyls (PCBs) and dioxins. Given that Galveston Bay has had large industrial complexes such as those along the Houston Ship Channel and in Texas City operating along its shore for more than 50 years; it should come as no surprise that some areas of the Lower Galveston Bay watershed have problems with contamination of chlorinated organic compounds. This type of contamination is often associated with high intensity land use (Figure 6.27). High intensity development is defined as having impervious surfaces account for 80 to 100 percent of

the total cover and is representative of large industrial and commercial complexes. State of the Bay

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6 As with metals, samples of chlorinated organic compounds are typically collected in the sediments rather than directly from the water column. In the case of these compounds, even better information may be obtained by analyzing concentrations in tissue of living organisms. Concentrations of chlorinated organic

CHAPTER compounds in fish tissue are discussed in Chapter 9.

Figure 6.27. The geographic distribution of high-intensity land use in 2005. Shaded in maroon are highly developed areas where people reside or work in high numbers. Impervious surfaces account for 80 to 100 percent of the total cover. This type of development is representative of large industrial and commercial complexes. Data source: (NOAA 2006). State of the Bay

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6 CHAPTER

PCBs are considered legacy pollutants. They were historically used in electrical equipment as an insulating medium in transformers. Even though their manufacture in the U.S. was banned more than 30 years ago, their use was not. In fact, some transformers still contain these compounds. For many years, PCBs have been found in sediments and in tissues of fish and shellfish in the Houston Ship Channel, and, more in the tissues of catfish and spotted sea trout in other areas of Galveston Bay. Contamination of fish and shellfish by PCBs and other chlorinated organic compounds, such as dioxins, has lead to a series of seafood consumption advisories issued by the TDSHS (Chapter 9). Unlike PCBs, dioxins are not considered legacy pollutants. Dioxins are by-products of chlorination processes, waste incineration, and paper-mill operations. Monitoring by the University of Houston conducted between 2000 and 2004 found dioxins (heptachlorodibenzo-p-dioxin or HPCDDs) in sediments of Buffalo Bayou, Cedar Bayou, the Houston Ship Channel, the San Jacinto River, and Upper and Lower Galveston Bay(TCEQ 2010) (Figure 6.28).Of those areas, the highest concentrations were found in the Houston Ship Channel.

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6 Figure 6.28. Concentrations of dioxin (total heptachlorodibenzo-p-dioxin) in the sediments of tributaries to Upper Galveston Bay, 2000–04. Data source: University of Houston (TCEQ 2010). CHAPTER

Monitoring data has identified one source of dioxin contamination as a site on the San Jacinto River just north of Interstate-10. The San Jacinto River Waste Pits were used as a disposal site for wastes from paper mill activities for more than 30 years (EPA 2009). Subsidence over the years submerged the waste pits, which now lie under the river. The site is listed on the National Priority List of Superfund sites. While the identification of this site may largely explain the dioxin contamination of Upper Galveston Bay, questions regarding the source of PCB contamination have not been answered. Industrial organic compounds are primarily sampled in sediments of the Houston Ship Channel where much of the bay’s industrial activity takes place. An indicator comparing sediment samples of these compounds to TCEQ (2008a) screening levels was initially developed by the Galveston Bay Indicators Project (Lester and Gonzalez 2005). As seen in the indicator (Figure 6.29), most areas of Galveston Bay, with the exception of the Houston Ship Channel, do not appear to have large problems with toxic organics in sediment. However, samples collected from the Houston Ship Channel show elevated concentrations of PCBs and semivolatile organics, including polycyclic aromatic hydrocarbons (PAHs). Some PAHs are manufactured, but most are created through the incomplete combustion of organic compounds. Two samples of lindane and chlordane collected in the year 2000 in West Bay exceeded the TCEQ screening levels.

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Figure 6.29. Indicator describing industrial organics in sediments of Galveston Bay and the Houston Ship Channel, 1970s and the years since 2000.Data sources: (HGAC 2010; TCEQ 2010). CHAPTER

Oil Spills One source of contaminants on which data is collected is spillage of petroleum products into bay waters by shipping vessels and industrial facilities. Petroleum is highly toxic to some estuarine organisms, particularly the larval stages. When spilled in water the lightest components evaporate and become air pollution. Heavier components may float and combine into tar balls. The heaviest components sink to the sediment, where they may damage benthic organisms, such as oysters. Petroleum compounds from a spill can be degraded by microbes present in the environment, but may remain at harmful levels for many years before complete degradation. The Texas General Land Office (TGLO) Oil Spill Prevention and Response Program has gathered data describing oil spills in the segments of the Galveston Bay system since 1998. Table 6.3 illustrates this data with summaries of the number and quantity of spills in Galveston Bay through 2009. The trend of decreasing spill number may be explained in part by improvements in detecting and describing spills. The volume of spills can be highly variable. The high spill volume in 2000 was due in large part to a facility spill of 70,000 gallons of heavy fuel oils in the Houston Ship Channel. The year 2001 saw 2 vessel spills totaling 80,000 gallons; one occurred in the Houston Ship Channel, the other in Galveston Bay. Oil spill data for 2008 are incomplete due to difficulties associated with collecting data after the landfall of Hurricane Ike in September. Of the 100 oil spills reported to the TGLO in the 30 days after Ike made landfall, information describing volume was available for 11 spills. Additionally, information describing the type of product spilled was largely absent. TGLO personnel were unable to gather data due to storm- related issues, including safety of agency personnel in the days after the storm and reallocation of personnel to hurricane-response activities in the weeks after the storm. According to the Federal Emergency management Agency (FEMA 2008), Hurricane Ike resulted in more than 200 pollution reports, including more than 180 sites in the Houston- Galveston area. It is likely that many Ike-related spills went unreported, given that numerous homes, stores, and office buildings

State of the Bay

were inundated by the storm –

6 surge. Figure 6.30. Oil sheens were evident in the bay in the days after Hurricane Ike. This aerial photograph was taken along the Bolivar Peninsula. Data source: NOAA.

CHAPTER

Table 6.3. Number and volume of oil spills reported annually by the TGLO in the Lower Galveston Bay Watershed, 1998–2009. Data are reported in table (top) and graph (bottom) form. Trends on the graph 2 are significant if R is greater than 0.25.Data source: (TGLO 2010).

Reported Volume Spilled (Gallons) Number of Reported Spills

1998 18,125 284 1999 33,021 387 2000 103,174 390 2001 123,828 397 2002 13,279 338 2003 10,381 315 2004 48,770 266 2005 20,678 246 2006 5,726 267 2007 6,915 306 2008 4,911 321 2009 27,279 229 Total 416,087 3,746 State of the Bay

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CHAPTER

Biological Monitoring of Contaminants The release of contaminants into water and sediment may be episodic, but it is persistent in the tissues of organisms living in or ingesting the water or sediment. Studies of the concentration of contaminants in the tissues of finfish and shellfish have been conducted to assess the potential for health effects from consumption of seafood (see Chapter 9) or the level of ecological effects from the pollution. The difficulty of measuring the concentration of contaminants in the water can be overcome if there is a method for concentrating them and collecting them over time. Nature has provided a collection and concentration device in the form of sessile benthic filter-feeding organisms. The most common in Galveston Bay is the oyster. Although it is not evenly distributed over the bay bottom, it is sufficiently common to use the concentration of pollutants in the tissue of oysters as an indicator of the prevalence of pollutant concentrations of concern.

Metals

Several studies of the concentration of metals in the tissue of Galveston Bay oysters have been published. Jiann and Presley (1997) reported on the concentrations of 7 metals in oysters collected from 15 sites during 1992–93. They concluded that problems from metal pollution in Galveston Bay were not serious when compared to other estuarine systems, such as Chesapeake Bay and Hong Kong Harbor. Arsenic averaged 4.92 parts per million dry weight in Galveston Bay collections, while the average for all Gulf of Mexico samples was 9.69 ppm (Morse et al. 1993; Jiann and Presley 1997). Most of the other metals studied had similar average concentrations in Galveston Bay and across the Gulf of Mexico.

Tissue samples (n = 613) collected from Galveston Bay finfish, blue crab and oysters by the TCEQ, DSHS, and the NOAA Mussel Watch Program were analyzed by the Galveston Bay Status and Trends Project (Gonzalez and Lester 2008) and compared to the TCEQ screening level for mercury in fish tissue from tidal waters (TCEQ 2008a). The majority of samples were below the screening level value of 0.525 mg/kg. The 2 highest concentrations of mercury found were 0.853 mg/kg, taken from a white bass in the Houston Ship Channel in 2004, and 0.65 mg/kg, sampled from a sheepshead in West Bay in 1999 (Figure 6.31).

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6 CHAPTER

Figure 6.31. Mercury in the tissues of fish, crabs, and oyster in Galveston Bay, 1974–2004.

Organics

Of all organic contaminants sampled in the tissues of Galveston Bay finfish, blue crab, and oysters by the TCEQ, DSHS, and the NOAA Mussel Watch Program, PCBs are the most problematic. Tissue data were analyzed and compared to the TCEQ screening level for PCBs in fish tissue from tidal waters (TCEQ 2008a). Prior to 1998, the majority of samples were below the screening level value of 0.0891 mg/kg. However, with advent of improved analytical techniques, elevated levels of PCBs were detected (Figure 6.32). This is also evidenced by the seafood consumption advisories issued by the DSHS in recent years (see Chapter 9).

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Figure 6.32. PCBs in the tissues of fish, crabs, and oyster in Galveston Bay, 1975–2005.

Summary The geographical areas of Galveston Bay with contamination problems are in regions of intense human activity, including urban, suburban, and industrial areas. The water and sediment quality of the bay is generally good, and there is a general trend of improvement. In many cases, substantial improvements are evident over the period from the 1970s to present. Water quality parameters of concern are fecal coliform bacteria, pH, and dissolved oxygen. The declining trend in concentrations of chlorophyll a noted in the last edition of this volume appears to have leveled out in recent years. Fecal-coliform concentrations in Galveston Bay tributaries are of concern. They have shown a decline in measured concentration but, unlike many of the water quality measures, they continue to exceed water quality criteria. Recent data suggest declines in pH and dissolved oxygen concentrations in State of the Bay

– some areas of the bay. The reasons for the declines are unknown at this time. 6

CHAPTER

Oil spills in Galveston Bay have declined in number since 1998. However, large spills such as those that occurred in 2000, 2001, and presumably 2008 (i.e., Hurricane Ike) can happen. Sediment quality is improving overall. Cadmium, chromium, copper, and lead concentrations have declined in sediments of the Upper Houston Ship Channel. Some metals, such as mercury, still exhibit spikes in concentration in this area in some years. Sampling of sediment contamination is temporally and spatially sparse, making careful assessment of progress difficult. Monitoring of water and sediment contamination by assaying the concentration in tissues of organisms shows elevated concentrations of PCBs and some spikes in mercury concentrations.

Literature Cited Begon, M., C. R. Townsend, and J. L. Harper. 2006. Ecology: from indivduals to ecosystems, fourth edition. Malden, Massachusetts Blackwell Publishing. Byun, D. S., X. Li, S. Kim, H. Kim, and I. Oh. 2008. Analysis of atmospheric deposition of nitrogen and sulfur in the Houston-Galveston airshed affecting water quality. Houston, Texas: Texas Commission on Environmental Quality, Galveston Bay Estuary Program. Day, J. W., C.A.S. Hall, G. P. Kemp, and A. Yanez-Arancibia. 1989. Estuarine Ecology. New York, New York: John Wiley and Sons. Earle, S. A. 1995. Sea change: a message of the oceans. New York, New York: Random House Publishing Group. EPA. 1980. A water quality success story, Lower Houston Ship Channel and Galveston Bay. Washington D.C.: United States Environmental Protection Agency. EPA. 2006. Volunteer estuary monitoring manual, a methods manual, second edition, EPA-842-B-06-003 Washington, D.C. : United States Environmental Protection Agency. EPA. Basic information: introduction to UAAs 2008. Available from http://www.epa.gov/waterscience/standards/uses/uaa/info.htm. EPA. NPL site narrative for the San Jacinto River waste pits 2009 [cited 30 June 2009. Available from http://www.epa.gov/superfund/sites/npl/nar1773.htm. FEMA. 2008. Hurricane Ike preliminary recovery assessment: Hurricane Ike impact report. Fries, J. S., G. W. Characklis, and R. T. Noble. 2008. "Sediment-water exchange of Vibrio sp and fecal indicator bacteria: Implications for persistence and transport in the Neuse River Estuary, North Carolina, USA." Water Research no. 42 (4-5):941-950. State of the Bay

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Gonzalez, L. A. , and L. J. Lester. 2008. Galveston Bay Status and Trends Final Report. Houston, TX: 6 Texas Commission on Environmental Quality, Galveston Bay Estuary Program. CHAPTER

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