TRENDS IN SELECTED WATER QUALITY PARAMETERS
FOR THE HOUSTON SHIP CHANNEL
TECHNICAL SECTION
WATER QUALITY MANAGEMENT BRANCH
U.S. EPA REGION 6
1445 ROSS AVENUE
DALLAS, TX 75202-2733
ENVIRONMENTAL ANALYSIS SECTION
SURVEILLANCE BRANCH
U.S. EPA REGION 6
1445 ROSS AVENUE
DALLAS, TX 75202-2733
^1. PROl^
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 6
1445 ROSS AVENUE, SUITE 1200
DALLAS, TX 75202-2733
October 13, 1992
MEMORANDUM
SUBJECT:
FROM:
Water Quality Management Branch (6W-Q)
Houston Ship Channel Water Quality Trends Report
TO:
Addressees
Attached for your information and use is a report (and appendices) entitled "Trends in
Selected Water Quality Parameters for the Houston Ship Channel." The report was prepared
by Water Quality Management and Surveillance Branch staff at the request of the Regional
Administrator. A brief summary report is also available upon request.
The report documents decreasing concentrations in numerous conventional and toxic
pollutants including TOC, TSS, fecal coliforms, ammonia, phosphates, and total arsenic and
copper. Increases in DO and decreases in BOD, Kjeldahl nitrogen and total cadmium,
mercury, nickel and zinc were most evident in upstream portions of the Ship Channel. The
report also cites a recent Texas Water Commission study documenting the utilization of this
waterbody by a fairly diverse aquatic community. However, it is important to note several
pollutants are still a concern, particularly nitrates and dissolved heavy metals (nickel,
mercury, arsenic, copper and lead).
This report should aid in evaluating water quality management needs for the Ship Channel
and Galveston Bay.
If you have any questions or know of other individuals who may want copies of the report,
please contact Philip Crocker at (214) 655-6644.
Attachment
Addressees:
J. Ferguson, 6W-P
J. Stiebing, 6E
R. Bo wen, 6W-QS
S. Parrish, 6W-QT
G. Horvath, 6W-QM
on Recycled Papi
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TRENDS IN SELECTED WATER QUALITY PARAMETERS FOR
THE HOUSTON SHIP CHANNEL
Philip A. Crocker*, Paul C. Koska**, Barbara J. Schrodt*
and Diane Evans*
September 1992
* Water Quality Management Branch, U.S. Environmental Protection
Agency, Dallas, Texas
** Surveillance Branch, U.S. Environmental Protection Agency,
Dallas, Texas
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EXECUTIVE SUMMARY
While many believe water quality in the Houston Ship Channel is
improving, water quality trends have not been adequately verified
and documented. An investigation was made utilizing ambient
monitoring data to make inferences on water quality trends for
selected parameters. Twenty-one water quality parameters were
assessed including conventional parameters (DO, TSS, fecal
coliforms, BOD and TOC), nutrients (ammonia, nitrate, nitrite,
Kjeldahl nitrogen, orthophosphate and total phosphorus), and heavy
metals (arsenic, cadmium, chromium, copper, lead, mercury, nickel,
selenium, silver and zinc). In addition, heavy metals and PCBs in
sediment are mentioned, although data are more limited for these
parameters. Concentrations over the last 10-20 years were plotted,
and assessed over time using statistical correlation (Pearson,
Spearman and Kendall tau-b correlations). The primary database
used was the Texas Water Commission state monitoring network (SMN)
data. The five Ship Channel stations assessed are located at
Morgans Point at the mouth, proceeding upstream to Channel Marker
120, San Jacinto Monument, at the Greens Bayou confluence, and the
turning basin (the upstream extent of the Ship Channel).
Trends differed by parameter and by station. Most encouraging
were the apparent declining trends at all or the majority of the
five stations for TOC, TSS, fecal coliform bacteria, ammonia,
orthophosphate, total phosphate, total arsenic, and total copper.
The data sets analyzed included remarked data (e.g., "<" or ">").
Therefore, to some degree apparent trends may have been influenced
by lowering of detection levels over time rather than actual
reductions in concentration. Apparent increasing trends were found
for nitrate and nitrite. Apparent declining trends were found at
one or two of the stations located furthest upstream, with no
significant changes at downstream stations for total cadmium, total
mercury, total nickel, and total zinc. Trends for total silver
varied considerably by station. Possible increasing trends were
found for total selenium at two of the five stations. A bimodal
pattern was evident for DO, BOD, and Kjeldahl nitrogen, showing
improving trends at upstream stations and worsening at downstream
sites. No significant changes were apparent for total chromium.
An evaluation of dissolved metals data for the Ship Channel during
1988-91 pointed to several of the metals as being a concern. The
dissolved metals of concern include: arsenic, which exceeded EPA
criteria 24% of the time; copper, which exceeded state water
quality standards 17% of the time; lead, which exceeded state
standards 10% of the time; mercury, which exceeded state standards
30% of the time; and nickel, which exceeded state standards 31% of
the time.
Limited data for heavy metals in bottom sediment suggest a
declining trend for arsenic, cadmium, lead and zinc at the turning
basin. Arsenic at Morgans Point also appears to be declining. In
contrast, possible increasing trends were found for copper and zinc
at Greens Bayou, and lead at the monument and Morgans Point.
A recent investigation by the Texas Water Commission documented a
diverse, viable fish community utilizing segments 1006 and 1007.
These findings probably reflect improvements in water quality
conditions, particularly with regard to dissolved oxygen.
ii
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OVERALL SUMMARY OF WATER QUALITY TRENDS BY PARAMETER
Improving
Total Organic Carbon
Total Suspended Solids
Fecal Coliform Bacteria
Ammonia
Organophosphate
Total Phosphate
Total Arsenic
Total Copper v
Total Cadmium*
Total Mercury*
Total Nickel*
Total Zinc*
Arsenic in Bottom Sediment
Cadmium in Bottom Sediment*
Differs bv Location
Dissolved Oxygen*
Biological Oxygen Demand*
Kjeldahl Nitrogen*
Total Lead
Total Silver
Copper in Bottom Sediment
Lead in Bottom Sediment
Zinc in Bottom Sediment
No Change
Total Chromium
PCBs in Bottom Sediment
Worsening
Nitrate
Nitrite
Selenium
* Improving at upstream station(s) only
iii
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WATER QUALITY TRENDS FOR HOUSTON SHIP CHANNEL
PARAMETER/LOCATION TRENDS*
DISSOLVED OXYGEN
Turning Basin t
Greens Bayou Confluence t
San Jacinto Monument t
Channel Marker 120
Morgans Point I
TOTAL SUSPENDED SOLIDS
Turning Basin -l
Greens Bayou Confluence <1
San Jacinto Monument I
Channel Marker 120 I
Morgans Point -
FECAL COLIFORMS
Turning Basin i
Greens Bayou Confluence I
San Jacinto Monument -4
Channel Marker 120 ~l
Morgans Point -
BOD 5-DAY
Turning Basin ;
Greens Bayou Confluence
San Jacinto Monument
Channel Marker 120 ~t
Morgans Point t
TOTAL ORGANIC CARBON
Turning Basin i
Greens Bayou Confluence I
San Jacinto Monument l
Channel Marker 120 l
Morgans Point I
AMMONIA-NITROGEN
Turning Basin ;
Greens Bayou Confluence I
San Jacinto Monument I
Channel Marker 120 4
Morgans Point l
NITRATE
Turning Basin t
Greens Bayou Confluence t
San Jacinto Monument t
Channel Marker 120 t
Morgans Point t
*t = Apparent Increasing Trend
I = Apparent Decreasing Trend
~t/~i = Possible Increasing/Decreasing Trend
- = No Apparent Trend
iv
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NITRITE
Turning Basin ~t
Greens Bayou Confluence t
San Jacinto Monument ~t
Channel Marker 120 ~t
Morgans Point
TOTAL KJELDAHL NITROGEN
Turning Basin 4
Greens Bayou Confluence 4
San Jacinto Monument 4
Channel Marker 120 -
Morgans Point t
ORTHOPHOSPHATE
Turning Basin 4
Greens Bayou Confluence 4
San Jacinto Monument 4
Channel Marker 120 4
Morgans Point ~4
TOTAL PHOSPHOROUS
Turning Basin 4
Greens Bayou Confluence 4
San Jacinto Monument 4
Channel Marker 120 4
Morgans Point 4
TOTAL ARSENIC
Turning Basin 4
Greens Bayou Confluence 4
San Jacinto Monument ~4
Channel Marker 120 4
Morgans Point ~4
TOTAL CADMIUM
Turning Basin -4
Greens Bayou Confluence ~4
San Jacinto Monument 4
Channel Marker 120
Morgans Point
TOTAL CHROMIUM
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Channel Marker 120
Morgans Point
TOTAL COPPER
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Channel Marker 120
Morgans Point
v
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TOTAL LEAD
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Channel Marker 120
Morgans Point
TOTAL MERCURY
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Channel Marker 120
Morgans Point
TOTAL NICKEL
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Channel Marker 120
. Morgans Point
TOTAL SELENIUM
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Channel Marker 120
Morgans Point
TOTAL SILVER
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Channel Marker 120
Morgans Point
TOTAL ZINC
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Channel Marker 120
Morgans Point
ARSENIC IN BOTTOM SEDIMENT
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Morgans Point
CADMIUM IN BOTTOM SEDIMENT
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Morgans Point
vi
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COPPER IN BOTTOM SEDIMENT
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Morgans Point
LEAD IN BOTTOM SEDIMENT
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Morgans Point
ZINC IN BOTTOM SEDIMENT
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Morgans Point
PCBs IN BOTTOM SEDIMENT
Turning Basin
Greens Bayou Confluence
San Jacinto Monument
Morgans Point
vii
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TABLE OF CONTENTS
Section Page
EXECUTIVE SUMMARY i
ACKNOWLEDGEMENTS xi
INTRODUCTION 1
Background 1
Purpose 1
METHODS AND MATERIALS 1
RESULTS AND DISCUSSION 3
Dissolved Oxygen 3
Total Suspended Solids 4
Fecal Coliforms 4
Biochemical Oxygen Demand 4
Total Organic Carbon 4
Ammonia-Nitrogen. 5
Nitrate 5
Nitrite 5
Total Kjeldahl Nitrogen 5
Orthophosphate 6
Total Phosphate 6
Arsenic 6
Cadmium 6
Chromium 6
Copper 7
Lead 7
Mercury 7
Nickel 8
Selenium 8
Silver 8
Zinc 9
Heavy Metals in Bottom Sediment 9
PCBs in Bottom Sediment 9
Ambient Toxicity 9
Fish Community 10
LITERATURE CITED 11
TABLES . 12
Table 1 - State Monitoring Network Stations 13
Table 2 - Long-term Mean, Standard Deviation,
Maximum Values and Relationship with Time 14
Table 3 - Concentrations of Dissolved Heavy Metals 21
FIGURES 23
Figure 1 - Location of Sampling Stations.. 24
Figure 2 - Discharge Flow, Ammonia and BOD Loading
for the Houston Ship Channel Over Time 25
Long-term Average and Trend;
Figure 3 - Dissolved Oxygen.. 26
Figure 4 - Total Suspended Solids 26
Figure 5 - Fecal Coliforms 26
viii
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TABLE OF CONTENTS
Continued
Section Page
FIGURES
Figure 6 - Biochemical Oxygen Demand 27
Figure 7 - Total Organic Carbon 27
Figure 8 - Ammonia-Nitrogen 27
Figure 9 - Nitrate 28
Figure 10 - Nitrite 28
Figure 11 - Total Kjeldahl Nitrogen.... 28
Figure 12 - Orthophosphate 29
Figure 13 - Total Phosphorus 29
Figure 14 - Total Arsenic 29
Figure 15 - Total Cadmium 30
Figure 16 - Total Chromium 30
Figure 17 - Total Copper 30
Figure 18 - Total Lead 31
Figure 19 - Total Mercury 31
Figure 20 - Total Nickel 31
Figure 21 - Total Selenium 32
Figure 22 - Total Silver 32
Figure 23 - Total Zinc 32
Figure 24 - Arsenic in Bottom Sediment 33
Figure 25 - Cadmium in Bottom Sediment 33
Figure 26 - Copper in Bottom Sediment 33
Figure 27 - Lead in Bottom Sediment 34
Figure 28 - Zinc in Bottom Sediment 34
Figure 29 - PCBs in Bottom Sediment 34
Figure 30 - Concentrations of Ammonia and Nitrate 35
APPENDICES
Appendix A - Example of STORET/SAS Program A-l
Appendix B - Statistical Summaries B-l
Dissolved Oxygen, Total Suspended Solids,
And Biochemical Oxygen Demand. B-2
Fecal Coliforms and Nutrients B-14
Heavy Metals in Water Column B-34
Heavy Metals and PCBs in sediment B-56
Appendix C - Plots of Concentrations Over Time C-l
Dissolved Oxygen C-2
Total Suspended Solids C-5
Fecal Coliforms C-8
BOD - 5 Day C-ll
Total Organic Carbon C-14
Ammonia-Nitrogen C-17
Nitrate C-20
Nitrite C-2 3
Total Kjeldahl Nitrogen C-26
ix
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TABLE OF CONTENTS
Continued
Section Page
APPENDIX C - Plots of Concentrations Over Time:
Orthophosphate C-2 9
Total Phosphorus C-32
Total Arsenic C-35
Total Cadmium C-38
Total Chromium. C-41
Total Copper C-44
Total Lead C-47
Total Mercury C-50
Total Nickel C-53
Total Selenium C-56
Total Silver C-59
Total Zinc C-62
Arsenic in Bottom Sediment C-65
Cadmium in Bottom Sediment C-68
Copper in Bottom Sediment C-71
Lead in Bottom Sediment C-74
Zinc in Bottom Sediment C-77
PCBs in Bottom Sediment C-80
x
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ACKNOWLEDGEMENTS
Valuable comments and suggestions on the appropriateness of the
statistical analyses were provided by Dr. James Robinson,
University of Texas at Arlington. Technical comments on the draft
report submitted by Dr. Neal Armstrong, University of Texas at
Austin, Mr. Kenneth Teague, U.S. Environmental Protection Agency-
Region 6 and Mr. George Guillen, Texas Water Commission-Houston
were much appreciated. Mr. Richard Seiler, Texas Water Commission-
Houston provided data on dissolved metals. Mr. Kelly Moseman,
Computer Science Corp., Dallas (U. S. EPA GIS Center), provided
assistance in developing the map of the Houston Ship Channel. We
also appreciate the assistance of Ms. Patti Willis, U.S.
Environmental Protection Agency, Region 6, who typed portions of
this report.
xi
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INTRODUCTION
Background
The Houston Ship Channel (HSC) is located in Harris County within
the San Jacinto River Basin on the southeast Texas coast. The
inland portion of the HSC, made up of State Water Quality segments
1005, 1006 and 1007 (TWC 1991) , extends a distance of 25 miles
between the mouth at Morgans Point to the turning basin. Water
quality in the HSC is influenced by a variety of point and nonpoint
sources. The Port of Houston serves as the second leading shipping
terminal in the U.S. Long-term impacts result from the nearly
constant ship traffic as well as episodic discharges and spills.
Periodic dredging is conducted to accommodate heavy ship and barge
traffic. The HSC is heavily impacted by point sources from both
municipal and industrial facilities. Approximately 400 facilities
discharge to the HSC and its tidal tributaries (TDWR 1984). Oil
and steel petrochemical industries along the HSC make it one of the
most highly industrialized waterbodies in the world. Fifty-five
percent of the U.S. production of polypropylene and 34% of the
polyethylene originates from industries located on the HSC. The
point source influence has resulted in an effluent dominated,
tidally mediated flow regime.
The system is also impacted by urban runoff from the cities of
Houston, Pasadena, Deer Park and others located on the HSC and its
tributaries. Other potentially important nonpoint pollutant
pathways include groundwater and atmospheric deposition. Numerous
tidal bayous heavily influence water quality conditions in the HSC.
A recent study (Crocker et al. 1991) found that ambient toxicity
using the mysid shrimp short-term chronic protocol was more
frequent in tidal bayous than in the HSC main stem. Nonetheless
these recent investigations have revealed fewer than expected water
quality criteria (TWC 1991; U.S. EPA 1991) exceedances and the
presence of a fairly diverse aquatic community compared to
conditions 10-20 years ago. These presumed improvements to water
quality, while encouraging, have not been adequately verified and
documented.
Purpose
The purpose of this report is to evaluate and document water
quality trends for the HSC during the last 10-20 years. This
evaluation does not serve to assess the universe of data and
information available, nor does it attempt to take into account
every possible parameter and sampling location. Rather, it should
be considered a preliminary evaluation in that only selected water
quality parameters were considered at five locations on the HSC.
The classes of parameters investigated include nutrients,
conventional parameters and heavy metals. Based on previous
studies (Crocker et al. 1991), these parameters were considered to
be the most important in terms of defining overall water quality.
METHODS AND MATERIALS
One of the most extensive databases available for assessing trends
in the HSC is the Texas Water Commission's State Monitoring Network
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(SMN). These data were accessed through STORET, the U.S. EPA's
national database. The five stations included in this study are
listed in Table 1. The water quality parameters evaluated include:
(1) conventional parameters - dissolved oxygen (DO), total
suspended solids (TSS), fecal coliforms, biochemical oxygen demand
(BOD) and total organic carbon (TOC); (2) nutrients - ammonia,
nitrate, nitrite, total Kjeldahl nitrogen, orthophosphate, and
total phosphorus; and (3) heavy metals (total) - arsenic, cadmium,
chromium, copper, lead, mercury, nickel, selenium, silver and zinc.
To a lesser degree heavy metals and PCBs in bottom sediments are
discussed. The period of record varied by parameter, with some
nutrients and conventional parameters extending up to 20 years.
Water quality data were retrieved from STORET using the PGM=RET
program, and trends were assessed using the SAS "CORR" procedure
(SAS 1990) . An example of this program is presented in Appendix A.
This procedure allows one to correlate concentrations of given
parameters with other parameters, or with time. Correlations
between time and the concentration of parameters of interest served
as the basis for making inferences regarding trends. Three
separate statistical tests were performed to measure the
association between time and parameter concentration: (1) Pearson
Product Moment Correlation - a parametric test assuming a normal
distribution, considered to be the most powerful of the three
procedures; (2) Spearman's Ranked Order Correlation - a
nonparametric measure that is calculated as the correlation of the
ranks of the variables; and (3) Kendall's tau-b - a nonparametric
measure calculated from the number of concordant and discordant
pairs of observations and uses a correlation for tied pairs (i.e.,
pairs of observations that have equal values of x or equal values
of y). All data, including remarked data (e.g., designated as
"less than" or "greater than") were included in the analysis. The
null hypothesis for these tests was that there is zero correlation
between time and parameter concentration (i.e., Ho:Rho=0).
It was considered important to utilize multiple statistical
analyses which would serve to collectively assess trends.
Singularly these analyses may not be fully representative. For
example, the assumption of normality may not hold, thus
compromising the representativeness of the Pearson Correlation.
Representativeness is maximized by utilizing three separate tests.
Agreement by all three tests would indicate a high degree of
confidence in the interpretation of trends. Pearson, Spearman, and
Kendall statistics are summarized in the report, and actual
probability values are presented in Appendix B. An additional
statistic, Hoeffding's Measure of Dependence, may be used to assess
the degree of dependence (including non-linear dependence) which is
not possible using the correlations above. Discussion of dependence
is beyond the scope of this report, although since some might be
interested, the statistics were included in Appendix B.
Trends for each specific statistical test were considered to be
significantly increasing or declining at a probability level
greater than or equal to 95% (i.e., P>0.95). Trends over time were
considered possibly significant if the probability was greater than
or equal to 90% but less than 95% (i.e., 0.90
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summarizing overall trends, if greater than 95% probability was
found using all three statistical tests, the parameter was assumed
to be significantly increasing or declining. If one or more
statistical test demonstrated a probability of greater than 90% the
parameter was considered to be possibly increasing or decreasing.
Lack of significance at the 90% level using all three tests
indicated no changes in concentration over time.
Several other items were developed to aid in assessing status and
trends. Concentrations over time were plotted for all parameters
of interest using the STORET program PGM=Plot. These plots are
least squares regressions incorporating all data (including
remarked data). These were considered valuable to provide visual
appreciation of trends. Plots for water and sediment parameters
are presented in Appendix C. The PGM=Plot program also furnished
the slope of the least squares regression line. These slope values
are presented in Table 2. Dissolved metals data for the period
1988-1991 were compiled and values were compared with the Texas
Water Quality Standards (TWC 1991) and/or the EPA water quality
criteria (U.S. EPA 1991). A least squares regression plot was
developed for cumulative discharge flow and loading rates for BOD
and ammonia over time for HSC facilities to compare with trends in
water quality. These data are compiled in tabular form by the TWC
and provided to EPA on a quarterly basis. Finally, available data
from the literature was reviewed to provide some information on the
nature of the aquatic community and the incidence and degree of
ambient toxicity.
RESULTS AND DISCUSSION
The results are presented in Table 2, are summarized graphically in
figures 3 through 30, and are briefly discussed by parameter below.
In considering these data it should be recognized that trends are
not necessarily absolute. The validity of trends hinges on the
amount of data and the assumption that statistical tests are
adequate to demonstrate patterns in the data. It is important to
realize that detection levels for most of the parameters assessed
have declined during the last 10-20 years. To some degree it is
possible that trends may be influenced by lowering of detection
levels.
Dissolved Oxvaen
Maintenance of adequate DO levels is important for protecting and
maintaining aesthetic qualities of a water body as well as a
healthy, diverse aquatic community. The trends analysis took into
account DO data collected at surface, bottom as well as other
depths. As would be expected, mean concentrations were lowest at
the turning basin (1.57 mg/1) and increase progressively moving
downstream to Morgans Point (7.09 mg/1). Significant increasing
trends in DO concentrations were apparent at the Turning Basin,
Greens Bayou and San Jacinto Monument. Surprisingly, the trend for
DO further downstream at Channel Marker 120 and Morgans Point is
decreasing. The reason for this is not known, although it is
possible that point source BOD loading in segment 1005 may also be
increasing. Another possible reason is that there may be a
decrease in higher DO concentrations resulting from supersaturation
caused by phytoplankton blooms.
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Total Suspended Solids
High TSS and turbidity levels interfere with recreational use and
aesthetic enjoyment of the water. In addition, the aquatic
community may be affected behaviorally (e.g., feeding, migration)
and physiologically (e.g., gill clogging; larval development).
Average concentrations were highest at the turning basin and
Morgans Point. Downward trends were evident at all stations except
for Morgans Point. The strongest downward trend was at the turning
basin where TSS is decreasing approximately 4 mg/l/yr. These
trends are consistent with the findings of Ward and Armstrong
(1991).
Fecal Coliforms
Fecal coliform bacteria levels reflect the degree of fecal
contamination, and serve as an indicator of microbial pathogens.
The state of Texas (TWC 1991) requires the 30-day geometric mean
not to exceed 200 colonies/100 ml, and 2000/100 ml where waters are
designated as having primary contact and non-primary contact uses,
respectively. Segment 1005 is designated as primary contact,
whereas segments 1006 and 1007 are both designated noncontact
waters. As with DO, fecal coliforms were highest at the turning
basin and improve seaward. Strong downward trends are evident at
the turning basin and Greens Bayou. Possible downward trends were
found further downstream, with no appreciable change at Morgans
Point. Under Section 304(1)(1)(A)(ii) of the Clean Water Act all
three segments of the HSC were identified as not achieving fecal
coliform water quality standards (U.S. EPA 1990).
Biochemical Oxygen Demand
The BOD test is often used as an indicator of the efficiency of
sewage treatment, measuring carbonaceous oxygen demanding
substances. It assumes that no toxic or inhibitory materials will
affect microbial activity. Average BOD was most elevated at the
turning basin, followed by Morgans Point. Downward trends were
found at the turning basin, suggesting improved control of BOD by
upstream municipal facilities. There were no significant trends at
Greens Bayou and San Jacinto Monument. BOD appears to be on the
rise at the lower stations. The downward DO trend at Morgans Point
seems to reflect the upward BOD trend. However, overall, BOD
loading to the HSC during the last eight years (1984-91) appears to
be decreasing steadily (Fig. 2.b). Loading is greatest during
winter months.
Total Organic Carbon
TOC is the combination of dissolved and suspended organic material
and serves as a measure of organic enrichment, which is often
related to BOD. There was a good database for TOC at all five
stations during the last 10-20 years. It is interesting to note
that significant downward trends were found, and the rate of
reduction was quite similar at each station.
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5
Ammonia-Nitrogen
Ammonia is an odorless, colorless, gaseous alkaline compound of
nitrogen and hydrogen which is highly soluble in water and is pH,
temperature and salinity dependent. Ammonia-nitrogen consists of
the unionized ammonia (NH3) (the more toxic form) and ammonium
(NH4+) . Ammonia is a concern with regard to toxicity to aquatic
life; causing algal blooms; and, through microbial oxidation, may
deplete DO concentrations. Ammonia and ammonium are the preferred
forms of inorganic nitrogen for most phytoplankton. As expected,
average concentrations are greatest at the turning basin and
decrease progressively as one moves downstream. As with TOC,
significant declines in NH4 are occurring at each station. These
findings appear to reflect the dramatic reductions in loading
resulting from increased sewage treatment efficiency demonstrated
during 1984-91 (Fig. 2.c).
Nitrate
The nitrate ion is formed through microbial oxidation of ammonia-
nitrogen. The most significant sources are sewage treatment plant
effluent and inorganic fertilizers. It is an important causative
agent in the eutrophication process. As with ammonia-nitrogen,
average concentrations were greatest in the turning basin and
decreased downstream, although differences by station were much
less extreme. Of great interest was the finding of significant
increasing trends at every station with the rate of increase
proportional to the average concentrations (i.e., highest at
turning basin, lowest at Morgans Point). The results suggest that
municipal treatment plants are increasing efficiency with regard to
discharges of ammonia-nitrogen, but the form of nitrogen is
shifting to the more oxidized form, nitrate. Reverse trends for
these two nutrients are occurring in the HSC (Fig. 31). The
conversion of ammonia to nitrate may be beneficial in terms of
reducing the risk of ammonia toxicity. However the phytoplankton
community is capable of shifting from ammonia to other nitrogen
sources, including nitrate. Therefore, nitrification requirements
do little or nothing to control nutrient enrichment effects.
Nitrite
Nitrite is an intermediary ion formed in the oxidation of ammonia-
nitrogen to nitrate. Although it is more toxic to aquatic life
than ammonia, nitrite concentrations in water bodies rarely reach
these levels of concern. Average concentrations were lowest at the
turning basin and Morgans Point, and about the same at the other
three stations. In general levels appear to be increasing although
this was most significant at the Greens Bayou location. The weaker
increases observed for nitrite may be due to effective oxidation to
nitrate in treatment plants or in the waterbody.
Total Kieldahl Nitrogen
The total Kjeldahl nitrogen analysis converts nitrogen components
of biological origin, such as amino acids, proteins, peptides and
other nitrogen compounds to ammonia. It is considered a measure of
total biologically available nitrogen. As with other nitrogen
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6
compounds, average concentrations were highest in the turning basin
and decreased downstream. A bimodal trend was found with
significant decreases over time at the three upstream stations, no
apparent trend at channel marker 120, and an upward trend at
Morgans Point. Increases may be due to point source inputs to
segment 1005.
Orthophosphate
Orthophosphate is one,of the major nutrients necessary for plant
nutrition. In excess of critical concentrations orthophosphate can
stimulate plant growth and cause eutrophication. Data on
orthophosphate was not available after 1985. Average
concentrations were highest at the turning basin and Greens Bayou
and decreased at downstream stations. Downward trends were
apparent at all stations, although were not highly significant at
Morgans Point.
Total Phosphorus
Total phosphorus is a measure of orthophosphate in addition to
other less biologically available inorganic and organically-bound
phosphorus compounds. It should be noted that total phosphorus and
orthophosphorus data are not directly comparable since the state
reports concentrations as mg/1 P and mg/1 P04, respectively.
Again, the averages were highest upstream at the turning basin,
decreasing downstream. Significant decreasing trends were found
for all sites.
Arsenic
Arsenic is a metalloid which is used for a variety of industrial
processes, including manufacture of glass, cloth and electrical
components. Arsenicals have also been used in formulation of
herbicides. Average concentrations of total arsenic by station
were quite similar. Downward trends were found at all stations
although trends were weakest at San Jacinto Monument and Morgans
Point. Table 3 indicates dissolved arsenic exceeds EPA human
health water quality criteria (at the 10"5 risk level) approximately
24% of the time. The greatest number of exceedances were found at
the HSC below Greens Bayou, indicating that the source of
contamination may be one or more discharges to Greens Bayou.
Cadmium
Cadmium is a biologically nonessential metal often associated with
mining waste, smelters, electroplating, pigment works, textile and
chemical industries. Overall, average concentrations by station
were quite similar, and concentrations appear to be on the decline,
although the trend was most significant at San Jacinto Monument.
Dissolved cadmium has not been detected by TWC and EPA (Table 3).
Chromium
Chromium salts are used extensively in metal finishing,
electroplating, cleaning agents and as mordants in the textile
industry. They are also used in cooling waters, in the leather
-------
7
tanning industry, in catalytic manufacture, in pigments and primer
paints, fungicides and wood preservatives. Mean total chromium
concentrations were greatest at the Greens Bayou station, with
levels at the other four stations being similar. There were no
significant trends evident. In most cases, dissolved chromium has
been below detection or at relatively low levels. Comparison of
state water quality standards with these data is not possible since
the standards are for either Cr+3 or Cr*6, rather than dissolved
combined chromium.
Copper
Copper occurs naturally and is an essential trace element for
plants and is also required in animal metabolism. However, even
very low concentrations of copper is toxic to marine life (chronic
water quality standard is 4.37 ug/1) . Copper is used in the
manufacture of metal alloys, electrical products, pesticides,
algicides, fungicides, paints and wood preservatives. The total
copper average was highest at the turning basin, with values at the
other four stations being comparable. Significant
declining trends were found for each station. Dissolved copper is
a concern in that about 17% of the samples analyzed exceeded the
state chronic aquatic life water quality standard of 4.37 ug/1.
The actual percentage of exceedances may be greater since
relatively high detection levels (10 or 20 ug/1) were used in most
cases.
Lead
Sources of lead include precipitation, lead dust fallout, erosion
and leaching of soil, runoff of streets and other surfaces. It
also originates from industrial processes including manufacture of
electrochemical batteries and the production of lead and lead
alloys. Average total lead concentrations were greatest at the
turning basin and Morgans Point. An apparent decreasing trend was
found at the turning basin, with possible decreasing trends at the
turning basin and possible increases at Morgans Point. Exceedances
of the state human health water quality standards for dissolved
lead were found in approximately 10% of the samples collected.
Mercury
Mercury is a highly biaccumulative and toxic liquid metal which
tends to adsorb to sediment particles and settle on the bottom
sediment. Mining, agriculture and waste discharges contribute to
natural levels. Average total mercury levels were fairly
consistent between stations (approximately 0.4 ug/1). This
historical average is well above the existing state water quality
standard for protection of human health (0.025 ug/1 total mercury).
Although negative slopes of concentrations over time were found at
four of the five stations, only at the turning basin was the
decline significant. Dissolved mercury, which has been monitored
in the HSC since 1988 or 1989 appears to be a significant water
quality problem in this system. Thirty percent of the dissolved
mercury values exceeded the water quality standard. There are no
obvious indications that these data are invalid (Ernest Heyer,
Texas Water Commission-Austin, personal communication). The data
-------
indicate the importance for addressing point source controls for
mercury. Further study of mercury levels in the HSC is
recommended.
Nickel
Natural sources of nickel in surface waters include weathering of
rocks, inflow of particulate matter, and precipitation.
Anthropogenic sources include burning of coal and other fossil
fuels, and discharges from industries including electroplating and
smelting. Average nickel concentrations were considerably higher
at the turning basin when compared with other stations.
Significant declines were found only at the turning basin (-10.232
ug/l/yr). However, except for the turning basin, total nickel data
was limited. Thirty-one percent of the dissolved nickel data
collected during 1988-91 exceeded the state aquatic life water
quality standard of 13.2 ug/1 (Table 3). Segment 1005 (San Jacinto
River/HSC) was listed under Section 304(1) (1) (B) of the Clean Water
Act based on exceedances of the state water quality standards for
nickel (U.S. EPA 1990). The State is presently in the process of
developing a nickel total maximum daily load (TMDL) for the HSC.
Selenium
Selenium is an essential trace element required for animal
metabolism, although it is toxic in excessive amounts. It occurs
naturally, particularly in association with sulfide ores of heavy
metals, and is used in photocopying, the manufacture of glass,
electronic devices, pigments, dyes and insecticides. Unlike data
for most of the other pollutants investigated, average
concentrations for selenium are lowest at the turning basin and
increase progressively downstream, with the highest value being at
Morgans Point. TWC monitoring data for total selenium was limited,
therefore it is difficult to draw conclusions concerning trends.
At first glance, levels at all stations appear to be increasing,
although possible increasing trends were found only at the monument
and channel marker 120. Dissolved selenium does not appear to be
a concern since all samples collected during 1988-91 yielded
concentrations below detection.
Silver
Silver is a physiologically nonessential element. Primary
anthropogenic sources of silver in surface waters include
industrial and smelting wastes, wastes in jewelry manufacture and
electrical supply, and in production and disposal of photographic
materials. Average concentrations for total silver were almost
exactly the same (about 12 ug/1) at all five stations. The picture
concerning trends in total silver in the HSC varies considerably by
station. A possible decreasing trend was found at the turning
basin, while possible increasing trends were present for stations
at Greens Bayou, the monument, and Morgans Point. Except for one
occasion, at the Greens Bayou station, dissolved silver was not
detected during 1988-91. Assessing silver is complicated by the
relatively high detection levels used (>10 ug/1), and because the
state standard applies to free ion, which is not normally analyzed.
-------
9
Zinc
Zinc is introduced to surface waters through natural processes, by
industrial sources such as galvanizing, photoengraving, and
manufacture of alloys, zinc oxide and other chemical products.
Average concentration of zinc at the turning basin (236 ug/1) was
two to three times greater than levels at other stations. The
turning basin also showed the most significant decline over time
(-16 ug/l/yr). Possible declining trends were found at the next
downstream station, Greens Bayou. Dissolved zinc concentrations
were fairly comparable by station although levels varied
considerably by date. In only one case (at Morgans Point) was the
state aquatic life water quality standard of 89 ug/1 exceeded.
Heavy Metals in Bottom Sediment
Monitoring of heavy metals in bottom sediments has been relatively
limited, therefore we believe data are insufficient to develop
definitive conclusions concerning trends. Also, it is difficult to
assess chemical concentrations in terms of toxic effect since EPA
does not yet have sediment quality criteria for metals. However,
some general findings can be discussed. For all four stations with
data the concentrations had the following pattern: zinc > lead >
copper > arsenic > cadmium. In all cases average concentrations
for metals were highest at the turning basin and decreased
progressively downstream. Significant decreasing trends were found
for arsenic at the turning basin and Morgans Point, and possibly at
the monument. Cadmium, lead and zinc increases were also
apparently significant at the turning basin. Possible declines for
copper and zinc at Greens Bayou, and lead at the monument and
Morgans Point were also found.
PCBs in Bottom Sediments
As with the metals, PCBs in bottom sediments are greatest (1040
ug/kg) at the turning basin, decreasing dramatically downstream.
There are not enough data to conclusively establish trends,
although available data did not show significant changes in
concentration were taking place.
Ambient Toxicity
Ambient toxicity testing serves to measure the cumulative
toxicological effect of all pollutants present in the water column.
Historical data for ambient toxicity is lacking. Crocker et al.
(1991) recently collected data for ambient toxicity for 12 stations
in the HSC system. Several toxicity testing organisms were used,
including sea urchin, algal, mysid shrimp, inland silverside, and
sheepshead minnow chronic protocols. The algal and mysid shrimp
tests served as the most sensitive indicators of ambient toxicity.
While the results were somewhat encouraging in that toxicity was
less prevalent than expected, there were some areas of particular
concern. Toxicity to the mysid was more frequently observed in the
tributaries (Greens and Sims Bayous) than the HSC itself. Algal
toxicity was also found in these bayous (however, these stations
were tested only once). Algal toxicity was most prevalent in
industrialized portions of the HSC at Greens Bayou, San Jacinto
-------
monument, and about one mile downstream of the monument.
Fish Community
The fish community serves as an overall indicator of ecological
health of the system. Seiler et al. (1991) has documented the
status of the fish community in HSC segments 1006 and 1007.
Sampling in the late 1950s found the portion of the HSC above the
tidal San Jacinto River to be virtually devoid of aquatic life. By
the mid-1970s diversity and utilization of segment 1006 (San
Jacinto River to Greens Bayou) by nekton had improved, with segment
1007 (Greens Bayou to turning basin) remaining depauperate. The
Seiler et al. (1991) study documented further improvement and
diversification of the fish community during 1988-89. The total
number of taxa collected were 76 for segment 1006 and 59 for 1007,
with 84 species collected overall. There was extensive use of the
upper portions of the HSC as habitat for juvenile fishes and
invertebrates. Segment 1006 maintains a diverse, viable fish
population throughout the year. During winter months richness and
abundance in segment 1007 equals or exceeds that of 1006. During
periods of low dissolved oxygen, segment 1007 continued to sustain
a viable shoreline assemblage of organisms. The study confirms a
trend of improvement in abundance and diversity over time which is
most likely reflective of water quality conditions resulting from
more stringent regulatory control of point sources discharges.
Another recent study by the Texas Water Commission presented in
Crocker et al. (1991) found that the number of taxa in segments
1005 and 1006 were comparable in January 1989, although
fluctuations in diversity and evenness were observed. Overall,
available data strongly indicate that all three HSC segments are
supporting an aquatic life use.
-------
LITERATURE CITED
Crocker, P.A., G.J. Guillen, R.D. Seiler, E. Petrocelli, M.
Redmond, W. Lane, T.A. Hoilister, D.W. Neleigh, and G. Morrison.
1991. Water quality, ambient toxicity and biological
investigations in the Houston Ship Channel and tidal San Jacinto
River. Technical Section, Water Quality Management Branch, U.S.
Environmental Protection Agency, Dallas, Texas October 1991.
SAS. 1990. SAS Procedures Guide, Version 6, Third Edition. SAS
Institute, Inc., Cary, NC. 705pp.
TDWR. 1984. Wasteload evaluations for the Houston Ship Channel in
the San Jacinto River Basin. Texas Department of Water Resources,
Austin, Texas. WLE-1. July 1984.
TWC. 1991. Texas Water Quality Standards. Texas Water Commission,
Austin, Texas. July 1991.
U.S. EPA. 1990. EPA Region 6 Section 304(1) final listing
decisions, June 2, 1990. U.S. Environmental Protection Agency,
Region 6, Dallas, Texas.
U.S. EPA. 1991. Toxic Substance Spreadsheet. October 29, 1991.
U.S. Environmental Protection Agency, Region 4, Atlanta, Georgia.
Ward, G.H. and N.E. Armstrong. 1991. Ambient Water and sediment
quality of Galveston Bay: Present status and trends (Draft).
Center for Research in Water Resources, University of Texas at
Austin. December 1991.
Seiler, R., G. Guillen and A.M. Landry. 1990. Utilization of the
Upper Houston Ship Channel by fish and macroinvertebrates with
respect to water quality trends. In: Proceedings of the Galveston
Bay Characterization Workshop, February 21-23, 1991, Houston,
Texas. Galveston Bay National Estuary Program. February 1991.
GBNEP P-6. Pp. 39-45.
-------
TABLES
-------
TABLE 1. STATE MONITORING NETWORK STATION LOCATIONS.
RIVER MILE
UPSTREAM
STATION NUMBER FROM MOUTH LOCATION LATITUDE LONGITUDE
10070800
24.8
HSC at Turning Basin
29°
45'
00"
95"
17'
20"
10060200
15.8
HSC at Greens Bayou
29°
44'
50"
95°
10'
04"
10060100
10.0
HSC at San Jacinto
Monument
29°
45'
15"
95°
05'
30"
10050200
7.1
HSC at Channel Marker
120
29°
44 '
30"
95°
03'
36"
10050100
0.4
HSC at Morgans Point
29°
40'
40"
94
58'
45"
-------
Table 2. Long-term Mean, Standard Deviation, Maximum Values, and Relationship with Time.
PARAMETER/
SLOPE
PERIOD
OF
TREND*
MAX.
STATION
(UNITS/YEAR)
N
RECORD
MEAN
SD
VALUE
PEARSON
SPEARMAN
KENDALL
Dissolved Oxvaen fma/1)
10070800
+0.103
1081
1970-91
1.57
2.08
10.4
t
t
t
10060200
+0.392
531
1982-91
3.25
2.22
9.6
t
t
t
10060100
+0.321
462
1971-91
4.51
2.29
10.6
t
t
t
10050200
-0.093
391
1983-91
6.38
1.87
11.9
4
-
-
10050100
-0.149
420
1982-91
7.09
1.78
11.6
4
I
Total Suspended
Solids (ma/H
10070800
-4.117
330
1970-91
41.64
58.42
500
4
4
4
10060200
-1.924
222
1976-91
24.99
32.01
326
4
4
4
10060100
-0.892
213
1976-91
29.88
27.74
181
4
4
4
10050200
-1.637
206
1976-91
37.49
48.36
504
4
4
4
10050100
+0.127
233
1976-91
40.01
38.85
255
Fecal Coliforms
(Colonies/lOOml)
10070800
-3,852
179
1973-91
27,116
65,299
450,000
4
4
4
10060200
-973
144
1976-91
7,723
20,112
145,000
4
4
4
10060100
-134
124
1976-91
2,255
5,843
43,000
-
4
4
10050200
-63
129
1976-91
558
1,137
12,000
4
~4
~ 4
10050100
-19
142
1976-91
229
698
4,000
-
BOD - 5 Dav fmcr/H
10070800
-0.220
315
1970-89
6.59
8.48
113.0
4
i
4
10060200
-0.039
191
1976-89
2.85
1.53
11.0
-
-
10060100
+0.014
179
1970-89
2.89
1.20
7.0
-
-
-
10050200
+0.056
174
1976-89
3.29
2.26
21.0
-
t
t
10050100
+0.227
202
1976-89
3.47
2.77
28.0
t
t
t
* Statistical trend depicted as follows: t= Apparent Increasing Trend; 4 = Apparent Decreasing Trend;
~t or -4 = Possible Increasing/Decreasing Trend; and -= No Apparent Trend.
-------
Table 2, Continued
PERIOD
PARAMETER/
SLOPE
OF
STATION
(UNITS/YEAR)
N
RECORD
MEAN
Total Orcranic
Carbon fmcr/1)
10070800
-0.331
283
1973-91
14.43
10060200
-0.392
195
1976-91
12.39
10060100
-0.383
183
1974-91
11.65
10050200
-0.319
175
1976-91
11.30
10050100
-0.390
207
1976-91
9.43
Ammonia-Nitrogen (mq/1)
10070800
10060200
10060100
10050200
10050100
-0.311
-0.156
-0.084
-0.042
-0.011
Nitrate fmcr/H
10070800
10060200
10060100
10050200
10050100
+0.148
+0.108
+0.063
+0.044
+0.029
Nitrite fma/1}
10070800
10060200
10060100
10050200
10050100
+0.007
+0.015
+0.004
+0.003
-0.001
324
1970-91
2.91
218
1976-91
1.72
203
1976-91
0.95
198
1976-91
0.56
227
1976-91
0.23
323
1972-91
0.65
219
1976-91
0.63
204
1976-91
0.53
198
1976-91
0.42
226
1976-91
0.29
144
1976-91
0.12
188
1977-91
0.25
172
1977-91
0.27
163
1977-91
0.23
130
1977-91
0.10
SD
TREND*
MAX.
VALUE PEARSON SPEARMAN KENDALL
14.23
5.54
5.87
6.54
6.01
230.0
32.0
49.0
62.0
51.0
3.24
1.41
0.77
0.50
0.24
39.00
9.10
4.05
3.15
1.61
1.11
0.75
0.55
0.42
0.68
7.43
5.51
5.69
4.32
9.92
t
t
t
t
t
0.21
0.29
0.28
0.24
0.11
2.15
1.92
1.51
1.31
0.48
-------
Table 2, Continued
PERIOD
PARAMETER/ SLOPE OF
STATION (UNITS/YEAR) N RECORD MEAN
Total Kieldahl Nitrogen fma/1)
10070800
-0.236
198
1976-91
3.93
10060200
-0.104
148
1977-89
3.09
10060100
-0.053
133
1977-91
2.31
10050200
+0.008
131
1977-89
1.87
10050100
+0.055
171
1977-91
1.52
Orthophosphate (ma/1)
10070800
-0.137
254
1973-85
4.71
10060200
-0.370
158
1976-85
5.04
10060100
-0.136
141
1976-85
3.31
10050200
-0.087
143
1976-85
2.37
10050100
-0.035
159
1976-85
1.46
Total Phosphorus
fmcr/1)
10070800
-0.039
323
1972-91
1.88
10060200
-0.070
217
1976-91
1.71
10060100
-0.039
202
1976-91
1.14
10050200
-0.028
195
1976-91
0.88
10050100
-0.013
225
1976-91
0.54
Total Arsenic (ua/1)
10070800
-3.192
67
1973-90
22.08
10060200
-2.293
46
1976-90
22.56
10060100
-1.251
48
1976-88
20.03
10050200
-1.837
45
1973-88
20.49
10050100
-0.348
46
1976-89
18.13
SD
TREND*
MAX.
VALUE PEARSON SPEARMAN KENDALL
3.87
1.14
0.94
0.80
0.75
50.20
6.30
5.44
5.20
6.40
2.10
3.22
1.51
1.07
0.63
11.35
20.96
8.75
5.23
3.98
1.02
0.93
0.51
0.40
0.22
11.60
7.10
3.10
2.45
1.63
34.87
18.89
17.99
22.32
13.24
189.0
95.0
90.0
140.0
55.6
ON
-------
Table 2, Continued
PARAMETER/
STATION
SLOPE
(UNITS/YEAR) N
PERIOD
OF
RECORD
MEAN
SD
MAX.
VALUE
TREND*
PEARSON SPEARMAN KENDALL
Total Cadmium (ua/1)
10070800
-0.342
91
1973-90
10.45
5.33
30.0
4
-4
-4
10060200
-0.388
46
1976-90
11.39
7.04
40.0
4
4
10060100
-0.451
48
1976-88
11.29
4.99
30.0
4
4
4
10050200
-0.248
45
1974-88
12.69
7.92
46.0
-
-
-
10050100
-0.500
46
1976-89
14.63
9.47
43.0
Total Chromium fua/1)
10070800
-0.437
85
1973-90
23.99
20.85
150.0
_
10060200
-4.410
39
1976-90
39.87
94.63
610.0
-
-
-
10060100
+0.157
41
1976-88
24.63
15.17
80.0
-
-
-
10050200
+0.424
38
1973-88
24.89
12.44
50.0
-
-
10050100
+0.239
40
1976-89
26.98
12.86
54.0
Total CoDuer fucr/1)
10070800
-15.423
91
1973-90
176.07
173.25
660.0
4
4
4
10060200
-11.192
46
1976-90
82.28
115.18
500.0
4
4
4
10060100
-10.105
48
1976-88
82.80
114.73
550.0
4
4
4
10050200
-11.613
45
1973-88
79.76
102.87
570.0
4
4
4
10050100
-13.500
46
1976-88
91.74
149.20
950.0
4
4
4
Total Lead
fuq/1)
10070800
-3.299
90
1973-90
55.92
46.31
262.0
4
4
4
10060200
-0.010
45
1976-90
39.29
29.00
150.0
-
-
-
10060100
+1.764
47
1976-88
46.51
33.44
170.0
-
t
t
10050200
-0.309
44
1973-88
45.95
40.76
200.0
-
-
-
10050100
-0.190
45
1976-89
57.99
45.35
220.0
~ t **
-
~~Increasing trend contradicts slope, and is apparently an artifact.
-------
Table 2, Continued
PARAMETER/
STATION
SLOPE
(UNITS/YEAR) N
PERIOD
OF
RECORD
MEAN
Total Mercurv
(ucr/1)
10070800
-0.042
91
1973-90
0.46
10060200
-0.020
46
1977-90
0.42
10060100
-0.005
48
1976-88
0.32
10050200
-0.083
45
1973-88
0.63
10050100
+0.011
45
1976-89
0.35
Total Nickel
rucr/11
10070800
-10.232
49
1973-90
118.90
10060200
+2.025
11
1983-90
17.55
10060100
-0.025
11
1983-88
14.18
10050200
-7.192
9
1973-88
21.56
10050100
+0.975
10
1983-89
21.70
Total Selenium (ucr/11
10070800
+0.312
14
1973-90
6.21
10060200
+2.777
11
1983-90
17.07
10060100
+7.609
11
1983-88
19.71
10050200
+13.620
8
1983-88
24.11
10050100
+6.567
10
1983-89
30.95
Total Silver
(uq/1).
10070800
-0.448
68
1973-90
11.04
10060200
+2.872
11
1983-90
13.09
10060100
+3.638
11
1983-88
12.45
10050200
-0.134
9
1973-88
13.22
10050100
+1.110
23
1980-89
12.39
SD
TREND*
MAX.
VALUE PEARSON SPEARMAN KENDALL
0.52 3.64 I I I
0.81 5.60 - - -
0.27 1.43 -
1.80 12.00 - - -
0.50 3.49 -
90.57 490.0 ill
16.46 55.0 - - -
5.55 25.0
33.72 110.0 I
13.42 50.0 - - -
6.29 20.0 - - -
21.38 70.4 - - -
20.07 59.9 -t t t
28.32 70.0 -t t t
34.41 103.2 - - -
8.67 50.0 4. - ~l
10.60 30.0 t
10.29 30.0 t t
12.16 30.0 - - -
7.49 30.0 t t ~t
-------
Table 2, Continued
PERIOD
PARAMETER/ SLOPE OF
STATION
(UNITS/YEAR)
N
RECORD
MEAN
Total Zinc
(ucr/1)
10070800
-16.002
72
1973-90
236.46
10060200
- 6.416
14
1976-90
79.29
10060100
- 1.928
14
1976-88
96.50
10050200
- 1.250
12
1974-88
107.25
10050100
- 1.507
27
1976-89
86.67
Arsenic in
Bottom Sediment
(mcr/kcf)
10070800
- 0.717
13
1977-90
6.96
10060200
- 0.382
8
1977-87
6.91
10060100
- 0.428
8
1977-90
6.54
10050100
- 0.502
10
1977-90
5.21
Cadmium in
Bottom Sediment
(ma/kcn
10070800
- 0.354
18
1974-90
5.23
10060200
- 0.014
8
1977-87
1.93
10060100
- 0.065
8
1977-90
2.43
10050100
- 0.117
10
1977-90
1.59
Cot>Der in Bottom Sediment (mcr/ka)
10070800
- 2.642
18
1974-90
54.29
10060200
+ 1.934
8
1977-87
34.39
10060100
+ 0.943
8
1977-90
17.40
10050100
- 0.028
10
1977-90
11.92
Lead in Bottom Sediment fmcr/kal
10070800
-10.518
18
1974-90
177.76
10060200
- 4.454
8
1977-87
57.01
10060100
+ 5.928
8
1977-90
56.76
10050100
+ 2.232
10
1977-90
28.75
TREND*
MAX.
SD VALUE PEARSON SPEARMAN KENDALL
275.60 1320.0 4. I *
61.03 225.0 -I * I
63.89 230.0 - - -
79.11 250.0 - - -
80.72 360.0 - - -
4.50 16.00 ill
2.79 11.90 - - -
5.09 17.90 - l -I
2.81 9.14 ill
2.88 11.00
1.22 4.77
2.16 7.00
1.36 4.00
36.55 193.20 -I
12.47 60.00 -t
8.98 33.00 - - -
4.29 20.00 - - -
86.98 350.00 I
39.90 97.80
35.21 115.00 t
15.55 54.00 t
-------
Table 2, Continued
PERIOD TREND*
PARAMETER/
STATION
SLOPE
(UNITS/YEAR) N
OF
RECORD
MEAN
SD
MAX.
VALUE
PEARSON
SPEARMAN
KENDALL
Zinc in Bottom
Sediment
fmcr/kcrt
10070800
-41.448
18
1974-90
540.92
336.97
16.56
I
10060200
+ 8.415
8
1977-87
182.88
52.91
270.00
t
t
10060100
+ 0.414
8
1977-90
89.19
58.83
190.00
-
-
10050100
+ 0.988
10
1977-90
63.89
25.44
110.00
-
PCBs in Bottom
Sediment
fucr/ka)
10070800
-70.810
11
1974-90
1039.51
2079.43
6430
_
10060200
+31.940
5
1978-87
413.24
428.72
1020
-
-
-
10060100
- 6.301
13
1978-90
90.79
163.76
580
-
-
10050100
- 0.894
8
1978-90
16.11
7.21
20
to
O
-------
TABLE 3.
CONCENTRATIONS OF DISSOLVED HEAVY METALS IN THE HOUSTON SHIP CHANNEL.
AMBIENT CONCENTRATION OF DISSOLVED HEAVY METAL (DG/L)
DATE ARSENIC CADMIUM CHROMIUM COPPER LEAD MERCURY NICKEL SELENIUM SEVER ZINC
10070800 - HOUSTON SHIP CHANNEL AT TURNING BASIN
5/16/89
2 a
<1
10
<10
<2
<0.4
15 b
<2
<16
30
8/8/89
<5
<1
<9
13 b
3
0.5 C
<11
<5
<16
30
11/20/89
<5
1
<9
15 b
<3
0.4 C
<11
<5
<16
2/22/90
<5
<1
<18
<10
<3
<0.2
40 b
<5
<32
70
5/24/90
<5
<1
<9
<10
<3
0.2 C
<11
<5
<16
<6
8/13/90
6 a
<1
<9
<10
<3
<0.2
<11
<5
<16
15
11/6/90
<5
<4
<9
<4
4 c
0.3 C
<11
<3
<16
30
5/8/91
<5
<1
<9
<4
<3
<0.2
15 b
<5
<16
35
8/13/91
<5
<2
<9
27 b
<3
<0.2
<11
<5
<16
30
10/28/91
8 a
<1
<9
<4
<3
<0.2
<11
<5
<16
40
10060200 -
HOUSTON
SHIP CHANNEL AT GRE
ENS BAYOU
8/1/88*
<18.4
<5
11
<20
<30
<0.2
29 b
<48
<10
1/12/89*
<46
<5
<10
<20
<30
<20
<48
<10
8/8/89
<5
<1
<9
<10
<3
0.5 C
<11
<5
<16
35
10/24/89
<10
<1
<20
<4
<5
<0.4
<20
<8
12 d
<20
11/20/89
<5
<1
<9
<10
4 C
<0.2
20 b
<5
<16
2/20/90*
<18
<5
<10
<20
<30
<0.2
<10
<19
<10
32
2/22/90
<5
<1
<18
<10
<3
0.4 C
20 b
<5
<32
80
5/24/90
6 a
<1
<9
<10
<3
0.3 C
<11
<5
<16
10
5/20/90*
8.9 a
<5
<10
<20
<5
<0.2
7.6
<20
<10
<30
7/30/90*
5.3 a
<5
<10
<20
<5
<0.2
<6
<4.8
<10
<40
8/13/90
6 a
<16
<9
<10
<3
0.3 C
<11
<5
<16
45
11/6/90
<5
<10
<9
<4
<3
<0.2
<11
<5
<16
20
8/13/91
<20
<1
<9
31 b
<3
0.5 C
<11
<20
<16
20
10/28/91
<20
<1
<18
19 b
<3
<0.2
<22
<20
<32
<12
10060100 -
HOUSTON SHIP CHANNEL AT SAN
JACINTO
MONUMENT
8/1/88*
<18.4
<5
<10
<20
<30
<0.2
33 b
<48
<10
1/12/89*
<46
<5
<10
<20
123 b,c
<20
<48
<10
11/20/89
<5
<1
<9
<10
<3
<0.2
25 b
<5
<16
15
2/20/90*
<18
<5
<10
<20
<30
<0.2
<10
<19
<10
30
2/22/90
<5
<1
<18
<10
<3
20 b
<5 v
<32
70
5/39/90*
6.5 a
<5
<10
<20
<5
<0.2
<6
<20
<10
<30
7/31/90*
5.2 a
<5
<10
<20
<5
<0.2
<6
<4.8
<10
<40
5/13/91
<5
<1
10
6 b
<3
<0.2
<11
<5
<16
105
8/13/91
<20
<1
<9
5b
<3
<0.2
20 b
<20
<16
25
a Exceeds EPA Hunan health water quality criteria,
b Exceeds state chronic aquatic life water quality standards,
c Exceeds state human health water quality standards,
d Exceedance of state chronic standard, assuming netal is present as free ion.
* Data from EPA/TWC Houston Ship Channel Study.
-------
TABLE 3, Continued
CONCENTRATIONS OF DISSOLVED HEAVY METALS IN THE HOUSTON SHIP CHANNEL.
AMBIENT CONCENTRATION OF DISSOLVED HEAVY METAL (UG/L)
DATE
ARSENIC
CADMIUM CHROMIUM
COPPER LEAD
MERCURY
NICKEL
SELENII
1 SILVER
ZINC
10050200 -
HOUSTON
SHIP CHANNEL AT CHANNEL MARKER 120
11/6/90
0.04 C
<11
10050100 -
HOUSTON
SHIP CHANNEL AT MOR
GANS POINT
5/16/89
<10
<1 10
<10 64 b,C
<0.5
20 b
<10
<16
45
11/20/89
<5
<1 <9
<10 <3
<0.2
<11
<5
<16
10
2/22/90
<5
<1 <18
<10 <3
<0.2
15 b
<5
<32
60
5/24/90
<5
<2 <9
<10 <3
<0.2
<11
<5
<16
<6
8/13/90
11 a
<1 <9
<10 <3
4.7 b,C
<11
<5
<16
18
11/12/90
<5
<10 10
<10 <3
0.3 C
<11
<5
<16
15
5/13/91
<5
<1 80
4 <3
<0.2
65 b
<5
<16
20
8/13/91
<1
<4 <3
<0.8
10/28/91
10
<1 <9
<4 <3
<0.2
<11
<20
<16
10
a Exceeds EPA human health Hater quality criteria,
b Exceeds state chronic aquatic life vater quality standards,
c Exceeds state hunan health vater quality standards,
d Exceedance of state chronic standard, assuming metal is present as free ion.
* Data from EPA/TWC Houston Ship Channel Study.
-------
23
FIGURES
-------
Loop 610
Interstate 1u
10 0 7 0 8 0 0
uf/a Io
A ait 0 14
SH-225
Loop biu
mm.
Ca.lv t(on
Bay
Environmental Protection Agency
Region 6 GIS Center
wmmm
* '¦ ¦]:/, . -mm
HOUSTON
FIG. 1
Location of Sampling Stations
-------
FIG. 2. DISCHARGE FLOW (a), CARBONACEOUS BIOLOGICAL OXYGEN
DEMAND-5 (b), AMMONIA LOADING (c), AND ULTIMATE OXYGEN
DEMAND (d) FOR THE HOUSTON SHIP CHANNEL OVER TIME.
a. Flow vs. Time
Flow (MOD)
700
600
600
600
200
100
Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul
Time (month/year)
c. Ammonia Loading vs. Time
Ammonia (Iba/day) (Thouaanda)
20
Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul
184 I as I 88
Jul
66
Time (month/year)
b. CBOD-5 vs. Time
C80P-6 Oba/day) (Thouaanda)
60
40
80
20
10
Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul
Time (month/year)
d. UOD vs. Time
UOD Oba/day) (Thouaanda)
160
140
120
100
60
60
40
20
Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul
164 I 66 I 66 I 67 i 66 I 60 I 60 I 61 I
Tims (month/year)
-------
r 7 8
r tq. o
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U)
£ b
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LJ
£ 4
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CD
£ 2
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28 n
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CO ' pn .
21 CO
C£ O
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O
8
u_ «1
CJ \
£ 1 4h
-4
LONG TERM
AVE.
TREND,
TURNIM5 GREENS SPIN JACINTO CrtiNNEl MCRwINS MB + UNITS/YR
BASIN BAYOU rtOHUNENT MARKER 120 POINT
-------
Fig. 6
f.
-l -J .
ILL
iiii
~ 15 -\
fl9- 7 " 1 ¦
llli
E-i -J _L_ 1 , , , ,
PLg. 8
! 1
21
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TURNING ORE
BASIN BA
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¦ LONG TERM
¦¦ Five.
¦1 TREND,
ENS SflN JACINTO CrtiNNEL MORGANS + UN ITS/YR
OU HOMjnENT MARKER 120 POINT -
-------
Fig. 9
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c 0.5-
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LONG TERM
AVE.
cc
11 -1 C,
P TREND,
TURNING ijfiEENS SAN JACINTO CHmNNEL rtORQrtNS HH + UNITS/YR
BBS IN BfllOU M0MJMENT MARKER 120 POINT
-------
5.5
ftg. 12
g>
£
4.5-
3.5
LJ
t
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Q_
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^ 15
Cl. 1
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FLg. 13 _
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£
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~I
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a
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FLg. 14
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\ 18
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14-
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§ 10"
CO o _
C£ °
-------
15-,
F L g. 15 14-
13-
- 12-
cn it -
3 10-
§ 8-
£ 7-
° r
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_i 4"
a: 3-
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f-1 1 -
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21
° 15-
CC '
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Fig. 17 160-
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CXL 100-
LJ
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Q_
8 60 H
5: 40H
O 20 H
£i
0-
-20-
LONG TERM
fiVG.
¦TREND,
+ UNITS/YR
BMSiN BH1UU HONURCNT MRR^ER 130 POINT -
-------
65-i
Pig. 18
55-
^45-
o 35
cc
CxJ
_J 25-
£ 15-
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-5
0-7
Peg. 19
~ 0.6
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^ °-4
cn
B 0-3'
cc
£ 0.2
£ o.i
o
1-1 0.0
-o.i
120-1
Fig. 20 108-
~ 96-
\
cn 84 -
- 72-
lj 60-
" 48 H
1l
z 36
cn 24 H
E-
° 12
0-
-12
LONG TERM
RVB.
TREND,
7URNIMG liREENS SPIN JFCINTO ChrtJNEL MORGANS ¦¦ + UNITS/YR
BASIN BAJ0U HONUIIEKT MARKER 120 POINT -
-------
35
fig. 21
_J 30-
N
cn
3 25
21
B, 20
sr
LJ
_J 15
LJ
in
_j 10-
CE
E>
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Fig. 22 JJ"1
_ 12 H
\ 11
CO 10-
J? 9
Cd M
uj 7-
3 6-
£ 5-
_J 4'
- L
O 2 H
-1
240-
Pig. 23 22Q'
_ 200
-> 180 -
160
- 140
o 120-
2
100
N
80-
cn 60-
f-i
o 40-
f<
20-
0-
-20-
A
LONG TERM
RVB.
TREND,
TURNING GREENS SAN JACINTO CHfWNEL MORiSrtNS ¦¦ + UNTTS/YR
BASIN BAJ0U MONUMENT MARKER 120 POINT - m
-------
ftg. 24 !z
LJ c j
2= b -
lj 5-
co
° j?
f-lJC
CD m
4 -
£
- 2-
1 -
lj n
CO u
cc:
^ -1
Fig. 25 £
LJ
^ 5
ii
~
u >1
co 4
3
O ^
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l H
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cr
° -1
65
Fig. 26 | 55
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co 13
O CO 35
f js:
H> \
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CD e 25
o
o
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15
cc
^ _ I ¦ H ¦ H ¦¦ LONG TERM
flVG.
TREND,
TURNING SREENS SflN JfiCINTC CHfNNEl MORGANS H + UNITS/YR
BPS IN BfiYOU MONUMENT MARKER 120 POINT -
-------
Fig. 27
20U -
150 -
125 -
Ftg. 28
550
f & 250 -
llOO-i
rig. 29
-100
TURNING GREENS SftN JflCINTO CHflNNEL MORGANS
BASIN BfilOU MONUMENT MARKER 120 POINT
LONG TERM
flVG.
TREND,
i UNIT5/YR
-------
30. Concentrations of Aimonia and Nitrate Over Time:
Houston Ship Channel at the Turning Basin.
i
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------- |