4.0       THE ENVIRONMENTAL SETTING

4.1              Water Quality

Kingston Harbour and Hunts Bay are known to receive low quality run-off from gullies as well as poorly treated sewage and industrial waste. In addition the harbour is affected by oil spills associated with operations of the Petrojam refinery and shipping in general [1]. These factors are likely to contribute to the quality of sediment to be dredged.

In the case of marine disposal, as spoil descends through the water column some pollutants (e.g. hydrogen sulphide) may be leached, leading to increased ambient concentrations. In dispersive waters these increases are usually rapidly diluted. In small estuaries and sheltered coastal waters however, such leaching may adversely affect organisms in the water column. It appears to be rare however for pelagic organisms to bioacumulate metals and organic chemicals released from contaminated dredged material although detecting such impacts and attributing them to a particular waste type is difficult [2].  

4.1.1    Discussion of Significance of Indicator Parameters

Total Suspended Solids (TSS): Solids settle under quiescent conditions and can directly smother reefs and coastal vegetation, while excess nutrients (especially nitrates and phosphates) promote the growth of algae which can eventually have the same smothering effect. The Draft National Policy for the Conservation of Coral Reefs (3) which mirrors international standards for coral reef protection, contains the following proposed criteria:

                        1.         Nitrogen (< .1 mg/l NO3) 

                        2.         Phosphorous (< .01 mg/l o-PO₄)

                        3.         Suspended Solids (< 10mg/l)

The ambient marine water quality standard proposed by the NRCA for phosphate is 0.001 - 0.055mg/l, while the range proposed for nitrate is 0.001 - 0.081mg/l.  Recent work out of UWI has indicated an annual average nitrate level in Hunts Bay (near the causeway) of 0.5mg/l at the surface and 0.2mg/l at the bottom of the water column. Average phosphate level over the same period was determined to be 0.04mg/l at the same site (4). In the vicinity of the channel, a nitrate level of 0.1mg/l and phosphate < 0.05mg/l has been indicated from recent work (1).

Lead (Pb), Chromium (Cr), copper (Cu), and cadmium (Cd) are present in trace quantities in the environment, but due to pollution sources, may be expected to become concentrated in the sediments of harbours. Locally, the use of leaded gasoline for decades, in addition to little control over potential sources such as the final disposal of industrial waste may contribute to the build up of lead in sediment which reaches the coast via numerous paved and unpaved gullies.

A previous study (5) indicated levels for these parameters in Kingston Harbour as follows:

                        Pb        -           1 -  6.0 Fg/L (ppb)    

                        Cr        -           0.6 – 13.0 Fg/L          

                        Cu        -           0.1 -  5.0 Fg/L           

                        Cd       -           0 -  4.0 Fg/L

There are no local ambient standards for these trace metals, but effluent standards have recently been established (6). These may provide a point of reference for the evaluation of sediment quality.  Table 2 gives USEPA criteria maximum concentrations (CMC), and criterion continuous concentrations (CCC) for the selected trace metals in water (7) as well as NRCA’s interim effluent standards. In addition, reference is made to recently developed USEPA criteria for classification of hazardous waste based on the level of a number of contaminants, among them, lead, chromium, and cadmium. (Table 3).    

Table 2:          USEPA Water Quality Criteria (Saltwater) & NRCA Interim Effluent Standards For Selected Trace Metals

The potential impact of lead on human health has been well documented and is summarised in the USEPA Fact Sheet (8). These however relate mainly to long term exposure to levels above the USEPA action level (> 0.015 mg/L in more than 10 percent of tap water samples). Lead does not appear to bioconcentrate significantly in fish but does in some shellfish such as mussels. Evidence suggests (8) that lead uptake in fish is localised in the mucous on the epidermis, the dermis, and scales so that the availability in edible portions does not pose a human health danger.

Most of the chromium in soil can attach strongly and does not dissolve easily in water (9). Although most of the chromium in water binds to dirt and other materials and settles to the bottom, a small amount may dissolve in the water.

Soil generally contains between 2 and 250 ppm copper, while the average concentration of copper in lakes and rivers is 4 ppb. Lakes and reservoirs recently treated with copper compounds to control algae or receive cooling water from a power plant may have high concentrations of dissolved copper. Once in natural water, much of this copper soon attaches to particles or converts to forms that cannot easily enter the body [10].

Cadmium is usually found as a mineral combined with other elements such as oxygen (cadmium oxide), chlorine (cadmium chloride), or sulphur (cadmium sulphate, cadmium sulphide). These compounds may dissolve in water but do not evaporate or disappear from the environment. All soils and rocks, including coal and mineral fertilisers, have some cadmium in them. The level of cadmium in most drinking water supplies is less than 1 ppb.

Table 3: Maximum Concentration of Contaminants For the Toxicity Characteristic

¹ Hazardous waste number.

² Chemical Abstracts Service number.

³ Quantitation limit is greater than the calculated regulatory level. The quantitation limit therefore becomes the regulatory level.

⁴ If o-, m-, and p-Cresol concentrations cannot be differentiated, the total cresol (D026) concentration is used. The regulatory level of total cresol is 200 mg/l.

[55 FR 11862, Mar. 29, 1990, as amended at 55 FR 22684, June 1, 1990; 55 FR 26987, June 29,

1990; 58 FR 46049, Aug. 31, 1993]

Subpart D-Lists of Hazardous Wastes

Source: Environmental Protection Agency - Federal Register: July 1, 1996, Part 5. 40 Cfr Part 257, Et Al. Criteria For Classification Of Solid Waste Disposal Facilities And Practices; Identification And Listing Of Hazardous Waste.

Cadmium has many uses in industry and consumer products such as batteries, pigments, metal coatings, and plastics, and is also found in fertilisers.

Cadmium in soil can enter water or be absorbed by plants. Fish, plants, and animals take up cadmium from the environment. Cadmium is found at hazardous waste sites at average concentrations of about 4 ppb in soil and 5 ppb in water. The human body keeps most cadmium in a form that is not harmful, but too much cadmium can overload the kidneys' storage system and cause health problems (e.g. kidney damage, and fragile bones) (11).

Chemical oxygen demand (COD) is a measure of the total amount of oxidisable material in a sample. By using a strong oxidising material, non-biodegradable and recalcitrant (slowly degrading compounds) which are not detected in the BOD test are included in COD determination. The NRCA stream loading effluent standard for COD is 100mg/l.

Biological oxygen demand (BOD) is one of the most important indices in the assessment of biodegradable organic water pollutants. Dredged sediment can be a significant source of BOD depending on the quantity of biodegradable material present. The NRCA stream loading effluent standard for BOD is <30mg/l and proposed draft ambient standard for this parameter is <1.7mg/l. Recent work by TEMN [1] has determined BOD levels of 0mg/l to 2mg/l in Kingston Harbour in an area covering the Petrojam loading facility in the east to Gordon Cay in the west. 

The level of dissolved oxygen (DO) in water dictates to a great extent the purpose for which it may be used, and in general gives an idea of the quality of the water (12). Waters in which all the oxygen has been used up appear dark in colour and have a foul odour. By exerting a BOD, dredged material can theoretically result in reduction of DO in overlying waters.  

In aerobic organisms oxygen insufficiency results in reduction in cellular energy and a subsequent loss of ion balance in cellular and circulatory fluids. If oxygen insufficiency persists, death will ultimately occur, although some aerobic animals also possess anaerobic metabolic pathways, which can delay lethality for short time periods (minutes to days). Anaerobiosis is well developed in some benthic animals, such as bivalve molluscs and polychaetes, but not in other groups, like fish and crustaceans (13). There is no evidence that any free-living animal inhabiting coastal or estuarine waters can live without oxygen indefinitely. The USEPA’s minimum concentration for saltwater dissolved oxygen criteria (14) (CMC), to ensure juvenile and adult survival is 2.3mg/l. The criterion continuous concentration (CCC) to ensure maximum growth effects is 4.8mg/l.

Hydrogen sulphide (H₂S) is a poisonous gas and a by-product of anaerobic (without-oxygen) decomposition of organic material. Un-ionised H₂S is the sulfide form considered the most toxic to aquatic fauna [15]. The USEPA saltwater criteria continuous concentration (CCC) for H₂S is 2.0l mg/l (7).

Organically enriched substrates such as those likely to be encountered in the harbour are essential to the energetics of benthic communities. However, harmful conditions may also arise as toxic metabolic byproducts (e.g., hydrogen sulfide) accumulate to excessive levels from decomposition of excess organic material. Literature review indicates effects on survival in 12 species of marine invertebrates (including a clam and two species of amphipods) at concentrations of 48 to > 50,098 mg/L. Effects on survival of two species of marine fishes also were reported at 17,892 - 23,856 mg/L (16).

Given the many sources of storm water run-off to Kingston Harbour, it was considered possible for the dredged sediment to contain significant amounts of the more persistent pesticides such as the organochlorines. It was also considered possible that deeper sediment could have residual levels of persistent pesticides no longer in use such as known carcinogens DDT and chlordane.

Some coliform bacteria occur naturally in soil while faecal coliform is an indicator of the presence of faecal mammalian waste. Given the discharge of raw sewage to the harbour, it was considered likely that faecal coliform would be detected in the water column.

4.1.2    Results and Observations

Water quality data collected at sites to be dredged are presented in Table 4. The results of sediment, and leachate/pore water analyses are presented in Table 5. Trace metals were determined at the parts per billion level in water samples, and at the parts per million level in sediment, leachate, and pore water. Sediment and ‘pore water’ samples collected in the channel and Hunts Bay had a strong odour of ‘rotten egg’ (hydrogen sulphide gas).

4.1.2.1 Water Chemistry Results

Trace metals

Copper and cadmium were absent from all water samples. However lead and chromium were determined to be present at much higher concentrations than detected through previous work in the harbour. 

Table 4:  Water Quality Data - Port Authority- Kingston Transhipment Port Expansion EIA

All measurements in mg/L unless otherwise stated

Table 5:  Sediment/Pore water/ Leachate Quality Data – Port Authority Kingston Transhipment Port Expansion EIA

The distribution of lead in the water column at stations established for this study is presented in Figure 4. Concentration of lead at all stations was determined to be in the range 26 ppb to 3142 ppb. The highest values were determined for the sample collected at Station 4 - Gordon Cay Bottom (3142 ppb), and Station 3 - the channel near Fort Augusta (2134 ppb). The lowest concentration of lead (26 ppb) was determined for the surface sample taken at Station 2 - the channel near Port Royal. Background level at Station 1 – 300m contour south of the Palisadoes strip near the gypsum loading pier (Figure 1) was also significant in surface and sub-surface samples (376 ppb and 236 ppb respectively). 

Distribution of total chromium is represented in Figure 5. Chromium concentration for all stations monitored was in the range 166ppb to 2262 ppb, the highest value being recorded for the sub-surface sample taken at Station 4B - the turning basin (near Gordon Cay).

Dissolved Oxygen

Dissolved oxygen (DO) levels at the stations monitored are illustrated in Figure 6. DO was determined to be in the range 4.6mg/l to 8.8mg/l at all stations monitored. The highest level was determined at the surface for Station 4 - near Gordon Cay. Sub-surface waters at this site also had the lowest DO concentration.

Temperature

Figure 7 is a histogram of temperature measurements. Temperature was determined to be in the range 25^oC to 28^oC with temperature in the deep sample being 0.5^o C to 1.0^oC below that at the surface. The exceptions were Stations 2 - the channel near Port Royal, and Station 5 - Hunts Bay near the causeway. At Station 2 subsurface temperature was 28^oC while at the surface it was 26^oC. At Station 5 sub-surface temperature was 27.5^oC while at the surface it was 27^oC.   

Nutrients

Nitrate (NO₃) distribution at the sampling sites is shown in Figure 8. With the exception of the sample collected from surface water at the Hunts Bay site (Station 5T) nitrate was determined to be 0.1mg/l. At Station 5T NO₃ was determined to be 0.4mg/l.

Phosphate (PO₄) distribution is shown in Figure 9. Phosphate level was determined to be .05mg/l or less at most stations. The exception was Station 5 - Hunts Bay where PO₄ was determined to be 0.1mg/l in samples taken from the surface and bottom of the water column.   

Suspended Solids/Turbidity

Suspended solids and turbidity were low at all sites monitored (Figures 10, and 11). Suspended solids were determined to be in the range 0 - 7mg/l, while turbidity was 0 - 8NTU.

Coliform

No Faecal coliform bacteria were detected in any of the samples. Low levels of total coliform were indicated in samples from Station 4 - Gordon Cay and, Station 5 - Hunts Bay. Samples from these sites were determined to have total coliform of 1MPN and 7MPN respectively.

Biological Oxygen Demand (BOD)

BOD concentrations at the sampling sites are shown in Figure 12. BOD was determined to be in the range 18mg/l to 27mg/l at all sites monitored. The highest value was detected for Stations 4 (Gordon Cay), and 5 (Hunts Bay), in the sub-surface samples. The other values in that range were detected for Station 1 (TOP) - south of Palisadoes (26.4mg/l) and Station 5 (Top) - Hunts Bay (26.2mg/l).

Chemical Oxygen Demand (COD)

COD measurements ranged widely (23 - 818mg/l).  The interference of chloride with the analytical method for the determination of this parameter limits its use as an indicator.

4.1.2.2             Sediment Chemistry Results

The results of sediment analysis and corresponding leachate analyses are presented in Table 5. Concentrations in sediment were determined on a dry weight basis, and water content for each sample was determined. With one exception, cadmium and copper were absent from all sediment samples. The exception was the sample taken at Station 5 - Hunts Bay that had no cadmium but was determined to have a copper concentration of 13.57ppm. Biological oxygen demand (BOD),

chemical oxygen demand (COD), and sulphide concentrations were significant in all samples. All samples exhibited a strong ‘rotten egg’ (hydrogen sulphide) odour.

Trace metals

Lead in sediment was determined to be in the range 44ppm - 97ppm. The lowest value was determined at Station 3 - Ship Channel near Fort Augusta. The highest value was determined in sediment from the Hunts Bay site (Station 5), while at Station 4 (near Gordon Cay) lead in sediment was 74.63ppm. Lead in leachate was determined to be in the range 60ppm - 68ppm. The lowest value was determined at Station 4 - near Gordon Cay, while the highest value was found at Station 5 - Hunts Bay.  At Station 3, lead in leachate was determined to be 62 ppm, and at Station 4 was determined to be 60ppm.

Lead in pore water was determined to be 0.175ppm at Station 4 (Gordon Cay), and 1.4ppm at Station 5 (Hunts Bay).

Chromium in sediment was determined to be 5ppm and 96ppm at Stations 3, and 5 respectively, while at Station 4 it was 6ppm. Chromium in leachate from Station 3 was 37ppm, at Station 4 it was 96ppm, and for Station 5 it was 6ppm. Pore water from Station 4 was determined to have a chromium concentration of 0.2ppm, while at Station 5 it was 0.4ppm.

Sulphide

Sulphide was determined to be 600ppm at Station 3 - channel near Ft. Augusta, 570ppm at Station 4 - Gordon Cay, and 700ppm at Station 5 - Hunts Bay. Pore water at Station 4 was determined to have a sulphide content of 99ppm, while at Station 5 sulphide in pore water was 88ppm.

Biological Oxygen Demand (BOD)

BOD of wet sediment from Station 3 was determined to be 1230mg/l, at Station 4 it was 1040mg/l, and at Station 5 it was 1140mg/l.   Leachate produced an equal or higher BOD than the respective sediment. At Station 3 leachate had a BOD of 1230mg/l, at Station 4 it was 1410mg/l, and at Station 5 leachate BOD was 1620mg/l.

Organics

Gas chromatography mass spectrometry (GCMS) analysis did not indicate the presence of any pesticide residues in the sediment samples examined. However the presence of at least two hydrocarbons were indicated. These were 17-Pentatriacontine, (found at Station 3), Benzene 1-pentylheptyl, and Benzene 1-butylheptyl. The latter two were detected at Station 5.

4.2       Ecology 

4.2.1    The Hunts Bay Habitat

The Hunts Bay area connects to the north-western portion of the harbour and consists of a shallow basin approximately 10 Km ² in area with an average depth of 2.5m. The sediments generally consist of soft mud and the overlying waters experience regular and considerable changes in salinity, nutrient and contaminant levels due to inputs from the various rivers and drainage gullies that enter into it.   Sources of these nutrients (nitrates and phosphates) and pollutants include fertilisers and insecticides used in agricultural activities upstream of the bay. The movement of layers of water with different salinities is modified by the restriction to outflow of water from the bay caused by the presence of a solid-fill Causeway with a narrow opening across the mouth of the bay. This counter clockwise circulation pattern within the bay (documented by UWI and Government of Jamaica researchers) appears to facilitate the retention and resultant stagnation of water masses in the general vicinity of the north eastern corner of the bay. This retention is reinforced during dry weather conditions and relaxes somewhat during the rainy season. The increased volume of water flowing into the bay during this time was reported to facilitate some limited flushing of this area of the bay and conditions improve for a short while before dry weather imposes itself on the cyclic hydrodynamics of the bay again. Most of the fishing activities are therefore concentrated in the middle and western portions of Hunts Bay. The results of a recent study (Webber, 1993) indicate that Hunts Bay may be even more impacted and degraded than other waters to be found in Kingston Harbour.

Studies on marine shrimps in Kingston Harbour by Chin (1994) indicated that at least two species lived for most of their life cycle in Hunts Bay and other western harbour muddy-bottomed areas. Further, Chin reported that shrimp regularly provided income for fishers operating from the Causeway  bridge ("Helsinki") area.

Submerged  transects 1, 2 & 3 (Figure 3) in Hunts Bay, had a thick layer of dense, anoxic mud. At a depth of 1.5m the visibility in the water column was 0.1 m. The substrate appeared to be abiotic and no fish or crustaceans were seen in the water column above or crawling on the mud bottom. This lack of faunal movement on or above the sediment could have been due in part to the high turbidity levels observed during the field visits.

Terrestrial transect No. 4 (Figure 3) demonstrated an impacted site that contained sparse grasses, shrubby vegetation as well as Seaside Mahoe and Mimosa trees on its landward margins towards the main road. This vegetation mixed with an associes of mature Black and White mangrove trees as one moved towards the perimeter of Hunts Bay. The shoreline was dried and no evidence of Red Mangroves was noted which would have been indicative of a healthier environment seeking to expand its boundaries into variably saline waters of the bay.

4.2.2    Hunts Bay Avifauna

At least sixteen (16) species of seabirds and colonial water birds were found in the mangroves and open waters of Kingston Harbour.  The harbour was an important nesting area for two species of regional conservation concern, namely the Brown Pelican and the Magnificent Frigate Bird.  Both species nested colonially in the mangrove trees around the harbour.  Both species were also common in the Hunts Bay area where they congregated around the area of activity associated with the small fishing communities taking offal and other “handouts” opportunistically.  The breeding status of these species in this section of the harbour was not known at the time of this study. They appeared to nest in the mangrove trees on the western side of the bay. No nesting or roosting activity was noted in the stand of mangroves on the eastern side of the bay that would be affected by reclamation activities.

Besides the nesting species, the area was an important roosting and feeding area for three (3) other species of regional conservation concern as is presented in the table (see Appendix 2).  The harbour area was also an important over-wintering site for Laughing Gulls (Larus atricilla), a species known to be uncommon in the wider Caribbean during the winter.   Laughing Gulls nested on the Port Royal cays where the number of nesting pairs were reportedly small.

Apart from the previously mentioned species, all of which are seabirds, the mangroves of the western Hunts Bay area were also populated by several other species - primarily herons and egrets some of which nested in the mangroves in the vicinity. 

 A list of the species of Rail, Ibis, Herons and Egrets observed within this area in the recent times is given below:

Green Backed Heron**

Little Blue Heron **

Cattle Egret **

Snowy Egret **

Great Egret

Great Blue Heron

Yellow-crowned Night Heron**

Black-crowned Night Heron**

Tricolored Heron

White Ibis**

Clapper Rail**

NB: species marked by asterisks (**) breed in the area.

All the above species were considered to be relatively common in suitable habitat, with the exception of the White Ibis, which was rare.   The White Ibis is known to nest on the Palisados side of Kingston Harbour in the mangroves.   Great Blue Herons are winter visitors to the area during which time they are relatively rare.

4.2.3    The Kingston Harbour Habitat

This natural embayment receives approximately 114 million litres (30 million gallons) of raw or partially treated sewage per day. It has also been subjected to repeated episodes of major dredging activity at various locations within its confines. Beginning in 1956, dredging activities were part of the construction techniques used in the conversion of a Royal Navy airbase to a commercial facility known as the Norman Manley International Airport. In 1969, dredging activities were also a part of the construction of the Causeway used to create a direct road link between the city of Kingston and the adjacent communities including Hellshire, Portmore and Braeton.  The establishment of Gordon Cay and the Rockfort Power Plant facilities, improving the port facilities at the Cement Company in the early and mid-nineties also required periods of extensive dredging activity in Kingston Harbour.  Repeated maintenance dredging of the ship channel in the vicinity of Two Sisters, Burial Ground and Greenwich Buoys and at Berths 8 & 9 has been carried out during the last ten to fifteen years.

Initial studies by Wade et al in the mid-seventies documented the degraded state of the benthos in both the inner and the outer harbour as a result of its function as a receiving body for numerous storm water, industrial waste and municipal sewage out-falls over the years. More recent studies by investigators from the University of the West Indies, as well as Government contractors hired to assess the status of the harbour, have confirmed these initial findings.  Anecdotal reports have been received over the years of significant mortality affecting the population of mussels that apparently once thrived on the mud floor of the harbour. An extensive area, ranging from Gunboat Beach in the east across Asprey Shallows and the Five Foot channel to the Two Sisters Buoy and north as far as the Pickering light, experienced mass mortalities of the mussel population. These episodes of mortality were reported to have been directly related to at least the first three to four of the earlier periods of dredging. Spoil was discharged within the confines of the harbour and large expanses of muddy water that wafted back and forth with the slow moving currents were reportedly observed by the fishermen in and around their commonly used fishing grounds.  More recent dredging exercises that involved the disposal at sites outside the harbour, but still relatively close to the coastline, were reported to have affected the normal migration routes of fishes such as the red snapper for a period of two years. Nets used by the fishermen at depths of 16-20 fathoms were also negatively impacted by the mud and they reportedly had to go further out to sea or move further east along the coastline to maintain catch levels.

Marine transects 5 & 6 (Gordon Cay) and 7 & 8 (Ships Channel) (Figure 3) were also indicative of low diversity, highly stressed environments. Visibility was only slightly better at 0.3m - 0.5m, and no fauna were observed in the water column or on the substrate at any of these stations. Substrate composition was thick mud with a few small holes indicating the presence of burrowing polychaetes. These stations were noted to be subject to repeated disturbance from construction and maintenance dredging activities as well as prop wash from manoeuvring ships.

4.2.4    Kingston Harbour Fishery

While the ecological linkages between magroves, seagrasses and related fishes in Kingston harbour were first described by Goodbody (1969), the role of Kingston Harbour mangroves as nurseries for fishable resources (fishes, spiny lobster, shrimps and conch) has been investigated only to a very limited extent (Tolan & Aiken, unpublished). What was found in nursery research was that there were at least 15 species of fishes repetitively associated with the Port Royal mangroves and the adjacent seagrass beds over the study period (1990-1992). Fishes were dominated by the silverside (Atherinidae), dusky anchovies (Engraulidae), sea bream (Archosargus rhomboidalis, family Sparidae, maccabacks (Gerreidae), porcupine fishes (Diodontidae), parrotfishes (Scaridae) and wrasses (Labridae). Most of these fish were not true coral reef fishes,